Linux-Architecture-Reference/DeviceTree/ch_devtree_pa.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
  Copyright (c) 2016 OpenPOWER Foundation
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  
-->
<chapter xmlns="http://docbook.org/ns/docbook"
         xmlns:xl="http://www.w3.org/1999/xlink" 
         version="5.0" 
         xml:id="dbdoclet.50569374_59715" 
         xml:lang="en">
  <title>Processor Architecture Binding</title>
  
  <section>
    <title>Data Formats and Representations</title>
    
    <para>The cell size shall be 32 bits. Number ranges for 
    <emphasis>n</emphasis>, 
    <emphasis>u</emphasis>, and other cell-sized items are consistent with
    32-bit, two's-complement number representation.</para>
    <para>The required alignment for items accessed with 
    <emphasis>a-addr</emphasis> addresses shall be four-byte aligned (i.e., a
    multiple of 4).</para>
    <para>Each operation involving a 
    <emphasis>qaddr</emphasis> address shall be performed with a single 32-bit
    access to the addressed location; similarly, each 
    <emphasis>waddr</emphasis> access shall be performed with a single 16-bit
    access. This implies four-byte alignment for 
    <emphasis>qaddrs</emphasis> and two-byte alignment for 
    <emphasis>waddrs</emphasis>.</para>
    
  </section>
  
  <section>
    <title>Memory Management</title>
    
    <section>
      <title>PA Address Translation Model</title>
      
      <para>This section describes the model that is used for co-existence of
      OF and client programs (i.e., OSs) with respect to address
      translation.</para>
      <para>The following overview of translation is provided so that the
      issues relevant to OF for the PA can be discussed. Details that are not
      relevant to OF issues (e.g., protection) are not described in detail; 
      <xref linkend="dbdoclet.50569387_99718" />, particularly Book III, should
      be consulted for the details. For the scope of this section, terms will
      be used as defined in 
      <xref linkend="dbdoclet.50569387_99718" />.</para>
      
      <section>
        <title>Translation requirements</title>
        
        <para>The default access mode of storage for load and stores (i.e., with
        translation disabled -- referred to as 
        <emphasis>Real-Mode</emphasis>) within the PA assumes that caches are
        enabled (in copy-back mode). In order to perform access to I/O device
        registers, the access mode must be set to Cache-Inhibited, Guarded by
        establishing a translation with this mode and enabling translation. Thus,
        even though most of a client program and/or OF can run with translation
        disabled, it must be enabled when performing I/O.</para>
        
      </section>
      
      <section xml:id="dbdoclet.50569374_41703">
        <title>Segmented Address Translation</title>
        
        <para>
        <emphasis role="bold">Note:</emphasis> The use of the term Virtual Address in this
        section refers to the PA definition, while the rest of the document uses
        the IEEE 1275 definition of virtual address.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> The following description of PA address
        translation is only one of several translation modes available and is
        given for reference only. See 
        <xref linkend="dbdoclet.50569387_99718" />for complete details.</para>
        <para>An Effective Address (EA) of a PA processor is 64(32) bits wide.
        Each EA is translated into an 80(52)-bit Virtual Address (VA) by
        prepending a 52(24)-bit Virtual Segment Id (VSID) to the 28 LSbs of the
        effective address. On 32-bit implementations, the VSID is obtained by
        indexing into a set of 16 Segment Registers (SRs) using the 4 MSbs of the
        EA. On 64-bit implementations, the VSID is looked up in a Segment Table
        using the 36 MSbs of the EA. Finally, the virtual address is translated
        into a Real Address (RA). This is done by mapping the Virtual Page-Number
        (VPN) (bits 0-67(39) of the VA) into a Real Page Number (RPN) and
        concatenating this RPN with the byte offset (12 LSbs of the VA). The
        mapping of VPN to RPN involves a hashing algorithm within a Hashed Page
        Table (HTAB) to locate a Page Table Entry (PTE) that matches the VPN and
        using that entry&#8217;s RPN component. If a valid entry is not found, a
        Data Storage Interrupt (DSI) or Instruction Storage Interrupt (ISI) is
        signalled, depending upon the source of the access.</para>
        <para>This process is not performed for every translation! Processors
        will typically have a Translation Look-aside Buffer (TLB) that caches the
        most recent translations, thus exploiting the natural spatial locality of
        programs to reduce the overhead of address translation. 64-bit
        implementations may also implement a Segment Lookaside Buffer (SLB) for
        the same reasons. On most PA processors, the TLB updates are performed in
        hardware. However, the architecture allows an implementation to use a
        software-assisted mechanism to perform the TLB updates. Such schemes must
        not affect the architected state of the processor unless the translation
        fails; i.e., the HTAB does not contain a valid PTE for the VA and a
        DSI/ISI is signalled.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> One unusual feature of this translation
        mechanism is that valid translations might not be found in the HTAB; the
        HTAB might be too small to contain all of the currently valid
        translations. This introduces a level of complexity in the use of address
        translation by OF, as discussed below.</para>
        
      </section>
      
      <section>
        <title>Block Address Translation</title>
        
        <para>To further reduce the translation overhead for contiguous regions
        of virtual and real address spaces (e.g., a frame buffer, or all of real
        memory), the Block Address Translation (BAT) mechanism is also supported
        by the PA. The Block Address Translation involves the use of BAT entries
        that contain a Block Effective Page Index (BEPI), a Block Length (BL)
        specifier and a Block Real Page Number (BRPN); the architecture defines 4
        BAT entries for data (DBAT entries) and 4 BAT entries for instruction
        (IBAT entries)<footnote xml:id="pgfId-550376">
          <para>The 601 has a single set of BAT entries that are shared by both
          instruction and data accesses.</para>
        </footnote>. BAT areas are restricted to a finite set of allowable
        lengths, all of which are powers of 2. The smallest BAT area defined is
        128 KB (217 bytes). The largest BAT area defined is 256 MB (228 bytes).
        The starting address of a BAT area in both EA space and RA space must be
        a multiple of the area's length.</para>
        <para>Block Address Translation is done my matching a number of upper
        bits of the EA (specified by the BL value) against each of the BAT
        entries. If a match is found, the corresponding BRPN bits replace the
        matched bits in the EA to produce the RA.</para>
        <para>Block Address Translation takes precedence over Segmented Address
        Translation; i.e., if a mapping for a storage location is present in both
        a BAT entry and a Page Table Entry or HTAB, the Block Address Translation
        will be used.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> Block Address Translation is a deprecated
        translation mode of the PA. This description is retained here for
        historical reference. See 
        <xref linkend="dbdoclet.50569387_99718" />for details on all supported
        addressing mechanisms.</para>
        
      </section>
    </section>
    
    <section>
      <title>Open Firmware&#8217;s use of memory</title>
      
      <para>OF shall use the memory resources within the space indicated by the
      
      <emphasis>real-base, real-size, virt-base</emphasis> and
      <emphasis>virt-size</emphasis> Configuration Variables defined for the PA.
      As described in the applicable platform binding, a mechanism is defined
      to enable OF to determine if its current configuration is consistent with
      the requirements of the client.</para>
      <para>If the client program has specific requirements for physical memory
      or address space usage, it may establish requirements for OF's physical
      and/or virtual address space usage by means of its program header. When
      OF loads the client program, it inspects the program header, and if its
      current usage of physical memory or virtual address space conflicts with
      that specified in the program header, OF shall set the 
      <emphasis>real-base</emphasis>, 
      <emphasis>real-size</emphasis>, 
      <emphasis>virt-base</emphasis>, and 
      <emphasis>virt-size</emphasis> to the configuration variables as specified
      in the header and restart itself. 
      <emphasis>Real-base</emphasis>, 
      <emphasis>real-size</emphasis>, 
      <emphasis>virt-base</emphasis>, and 
      <emphasis>virt-size</emphasis> may be specified as -1, in which case the
      firmware is permitted to choose appropriate values for the variables
      specified as -1.</para>
      <para>If the values of the 
      <emphasis>real-size</emphasis> and/or 
      <emphasis>virt-size</emphasis> configuration variables do not provide
      sufficient memory and/or virtual address space for the firmware's own
      use, then the firmware shall not attempt to load a client program and the
      condition should be reported to the user. The possibility of not being
      able to comply with limitations on firmware's size should be tested as
      the firmware is coming up in order to handle the possibility that a user
      established an unworkable limitation on the size. Clients can minimize
      this exposure by setting size to -1 and allowing OF to choose the
      size.</para>
      <para>A PA OF binding shall support two different addressing models,
      depending upon the setting of the 
      <emphasis role="bold"><literal>real-mode?</literal></emphasis> Configuration Variable. This variable
      indicates the OF addressing mode that a client program expects; 
      <emphasis role="bold"><literal>false</literal></emphasis> (0) indicates Virtual-Mode, 
      <emphasis role="bold"><literal>true</literal></emphasis> (-1) indicates Real-Mode; the default value of 
      <emphasis role="bold"><literal>real-mode?</literal></emphasis> is implementation dependent.</para>
      <para>The management of 
      <emphasis role="bold"><literal>real-mode?</literal></emphasis> is analogous to 
      <emphasis role="bold"><literal>little-endian?</literal></emphasis>. OF determines its addressing mode
      using the value of 
      <emphasis role="bold"><literal>real-mode?</literal></emphasis>. If the current state of 
      <emphasis role="bold"><literal>real-mode?</literal></emphasis> (and hence, the current state of OF) is
      incorrect, it shall set 
      <emphasis role="bold"><literal>real-mode?</literal></emphasis> appropriately and reset itself, possibly
      by executing 
      <emphasis>reset-all</emphasis>.</para>
      <para>Memory that cannot be allocated for general purpose use, for
      example physical memory on LoPAR systems used for interrupt vectors and
      implementation specific areas, shall not appear in the &#8220;
      <emphasis>available</emphasis> &#8221; property of the 
      <emphasis>memory</emphasis> node. A Client Program that needs to use such
      memory for its architected purpose must not claim that area prior to
      use.</para>
      <para>In the following two sections, some of conventions in Real-Mode and
      Virtual-Mode address translations are described. Remaining sections
      describe the assumptions that OF makes about the state and control of the
      system in regard to OF&#8217;s use of system resources for three OF
      interfaces (e.g. Device, User and Client interfaces).</para>
      
      <section xml:id="dbdoclet.50569374_25139">
        <title>Real-Mode</title>
        
        <para>In Real-Mode (when 
        <emphasis role="bold"><literal>real-mode?</literal></emphasis> is 
        <emphasis role="bold"><literal>true</literal></emphasis>), the use of address translations by OF and its
        client are independent. Either they do not use translation, or their
        translations are private; they do not share any translations. All
        interfaces between the two must pass the real address of the data. Any
        data structure shared by OF and its client that refers to 
        <emphasis>virt</emphasis> addresses in 
        <xref linkend="dbdoclet.50569387_45524" />, or this binding, must be real
        addresses.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> In particular, that the address of the Client
        interface handler, that is passed to the client, has to be a real
        address.</para>
        <para>The Configuration Variables 
        <emphasis>real-base</emphasis> and 
        <emphasis>real-size</emphasis> should indicate the physical memory base
        and size in which OF must locate itself. In Real-Mode, the Configuration
        Variables 
        <emphasis>virt-base</emphasis> and
        <emphasis>virt-size</emphasis> do not have meaning and should be set to
        -1.</para>
        
      </section>
      
      <section>
        <title>Virtual-Mode</title>
        
        <para>When 
        <emphasis role="bold"><literal>real-mode?</literal></emphasis> is 
        <emphasis role="bold"><literal>false</literal></emphasis>, OF shall configure itself to run in 
        <emphasis>Virtual-Mode</emphasis>. In Virtual-Mode, OF and its client
        will share a single virtual address space. This binding provides
        interfaces to allow OF and its client to ensure that this single virtual
        address model can be maintained.</para>
        <para>The Configuration Variables 
        <emphasis>virt-base</emphasis> and
        <emphasis>virt-size</emphasis> should indicate the virtual address space
        base address and size that OF should use. The Configuration Variables 
        <emphasis>real-base</emphasis> and 
        <emphasis>real-size</emphasis> should indicate the physical memory base
        and size in which OF must locate itself.</para>
        
      </section>
      
      <section>
        <title>Device Interface (Real-Mode)</title>
        
        <para>While OF is performing system initialization and probing functions,
        it establishes and maintains its own translations. In particular, it
        maintains its own Page Tables (and/or BAT entries) and handles any
        DSI/ISI interrupts itself.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> In Real-Mode, all translations will be 
        <emphasis>virt=real</emphasis>; the primary reason for translation is to
        allow appropriate I/O accesses.</para>
        
      </section>
      
      <section>
        <title>Device Interface (Virtual-Mode)</title>
        
        <para>OF will establish its own translation environment, handling DSI/ISI
        interrupts as in the Real-Mode case. However, this environment will, in
        general, contain translations in which virtual addresses do not equal
        real addresses. The virtual address space used by OF must be compatible
        with its client.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> Since these virtual addresses will be used by
        the Client and/or User Interfaces (e.g., for pointers to its code,
        device-tree, etc.), their translations must be preserved until the client
        OS decides that it no longer requires the services of OF.</para>
      </section>
      
      <section>
        <title>Client Interface (Real-Mode)</title>
        
        <para>In Real-Mode, addresses of client data are real.; the client must
        ensure that all data areas referred to across the Client Interface are
        valid real addresses. This may require moving data to meet any
        requirements for contiguous storage areas (e.g., for 
        <emphasis role="bold"><literal>read/write</literal></emphasis> calls). Translation shall be disabled
        before the client interface call is made.</para>
        <para>OF will typically have to maintain its translations in order to
        perform I/O. Since the client may be running with translation enabled
        (except for the Client interface call), OF shall save the state of all
        relevant translation resources (e.g., SDR1, BATs) and restore them before
        returning to the client. Likewise, it 
        <emphasis>may</emphasis> take over interrupts for its own use (e.g., for
        doing &#8220;lazy&#8221; allocation of BATs); it shall preserve the state
        of any interrupt vectors for its client.</para>
        <para>Since the state of the address translation system is not
        predictable to any interrupts, the client shall ensure that interrupts
        are disabled before calling the Client Interface handler and call the
        handler from only one CPU at a time. The client shall also ensure that
        other processors do not generate translation exceptions for the duration
        of the call.</para>
        <para>Client programs are not required to assume responsibility for
        physical memory management. The client program must use the OF claim
        client interface service to allocate physical memory while physical
        memory is managed by OF. Physical memory shall remain managed by OF until
        the client program defines the real-mode physical memory management
        assist callbacks. Physical memory must be managed by the client program
        once the client program defines the real-mode physical memory management
        assist callbacks. OF shall use the client program's real-mode physical
        memory management assist callbacks to allocate physical memory after the
        client program has assumed physical memory management.</para>
        <para>In Real-Mode, 
        <emphasis role="bold"><literal>claim</literal></emphasis> methods shall not allocate more pages than are
        necessary to satisfy the request.</para>
        
      </section>
      
      <section xml:id="dbdoclet.50569374_96317">
        <title>Client Interface (Virtual-Mode)</title>
        
        <para>Client interface calls are essentially &#8220;subroutine&#8221;
        calls to OF. Hence, the client interface executes in the environment of
        its client, including any translations that the OS has established. E.g.,
        addresses passed in to the client interface are assumed to be valid
        virtual addresses within the scope of the OS. Any DSI/ISI interrupts are
        either invalid addresses or caused by HTAB &#8220;spills&#8221;. In
        either case, the OS has the responsibility for the handling of such
        exceptions.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> Addresses that the OF internal use will be
        those that were established by the Device interface (or, by subsequent
        actions of the Client or User interface). Thus, the client must preserve
        these OF translations if it takes over the virtual memory management
        function.</para>
        <para>In addition to using existing translations, the Client Interface
        might require the establishment of new translations (e.g., due to 
        <emphasis role="bold"><literal>map-in</literal></emphasis> calls during 
        <emphasis role="bold"><literal>open</literal></emphasis> time), or the removal of old translations (e.g.,
        during 
        <emphasis role="bold"><literal>map-out</literal></emphasis> calls during 
        <emphasis role="bold"><literal>close</literal></emphasis> time). Since this requires altering the
        Client&#8217;s translation resources (e.g., Page Tables), possibly
        handling spill conditions, OF cannot know how to perform these
        updates.</para>
        <para>Hence, there shall be 
        <emphasis role="bold"><literal>callback</literal></emphasis> services provided by the client for use by
        OF for such actions; see 
        <xref linkend="dbdoclet.50569374_11616" />.</para>
        <para>In order to let clients (i.e., target OSs) know where OF lives in
        the address space, the following rules shall be followed by an OF
        implementation for the PA and by client programs.</para>
        <para>OF:</para>
  
        <itemizedlist>		      
          <listitem>
            <para>OF shall maintain its &#8220;translations&#8221;
            &#8220;mmu&#8221;-node property (see 
            <xref linkend="dbdoclet.50569374_34579" />)</para>
          </listitem>
          
          <listitem>
            <para>OF&#8217;s 
            <emphasis role="bold"><literal>claim</literal></emphasis> methods shall not allocate more pages 
            than are necessary to satisfy the request.</para>
          </listitem>
          
          <listitem>
            <para>When a client executes 
            <emphasis role="bold"><literal>set-callback</literal></emphasis>, OF shall attempt to invoke the
            &#8220;translate&#8221; callback. If the translate callback is
            implemented, OF shall cease use of address translation hardware, instead
            using the client callbacks for changes to address translation.</para>
          </listitem>
        </itemizedlist>		      
  
        <para>The 
        <emphasis role="bold"><literal>exit</literal></emphasis> service must continue to work after a 
        <emphasis role="bold"><literal>set-callback</literal></emphasis> that takes over address translation.
        This implies that OF takes responsibility for address translation
        hardware upon 
        <emphasis role="bold"><literal>exit</literal></emphasis> and must maintain internal information about
        translations that it requests of the client.</para>
        <para>Client Programs:</para>
        
        <itemizedlist>		      
          <listitem>
            <para>Client programs that take control of the management of address
            translation hardware and expect to be able to subsequently invoke OF
            client services must provide callbacks to assist OF in address
            translation (see 
            <xref linkend="dbdoclet.50569374_11616" />).</para>
          </listitem>
          
          <listitem>
            <para>A client program shall not directly manipulate any address
            translation hardware before it either a) ceases to invoke OF client
            services or b) issues a 
            <emphasis role="bold"><literal>set-callback</literal></emphasis> to install the &#8220;translate&#8221;
            callback.</para>
          </listitem>
        </itemizedlist>		      
        
        <para>
        <emphasis role="bold">Note:</emphasis> The intended sequence is that a client program
        will first issue a set-callback and then take control of address
        translation hardware. Address translation hardware includes BAT entries,
        page table, segment registers, Machine State Register and the interrupt
        vectors relating to translation faults.</para>
        
      </section>
      
      <section>
        <title>User Interface (Real-Mode)</title>
        
        <para>In Real-Mode, OF regains total control of the system. As with the
        Client interface in Real-Mode, it should save the state of the
        translation resources (including interrupt vectors) upon entry and should
        restore them upon exit.</para>
        
      </section>
      
      <section>
        <title>User Interface (Virtual-Mode)</title>
        
        <para>When the User interface is invoked, OF is responsible for managing
        the machine. Therefore, it will take over control of any relevant
        interrupt vectors for its own handling. In particular, it will take over
        DSI/ISI handling in order to report errors to the user for bad addresses,
        protection violations, etc. However, as described above, one source of
        DSI/ISI may simply be HTAB spills. As with the case of 
        <emphasis role="bold"><literal>map-in</literal></emphasis> and 
        <emphasis role="bold"><literal>map-out</literal></emphasis> calls, the User interface cannot know how to
        handle such spill conditions, itself, or even if this is, in fact, a
        spill versus a bad address.</para>
        <para>Hence, this binding defines 
        <emphasis role="bold"><literal>callback</literal></emphasis> services that the client provides for use by
        OF; see 
        <xref linkend="dbdoclet.50569374_11616" />.</para>
        
      </section>

    </section>
    
  </section>
  
  <section>
    <title>Properties</title>
    <para>This section describes the standard properties of a PA OF
    implementation.</para>
    
    <section xml:id="dbdoclet.50569374_58081">
      <title>CPU properties</title>
      <para />
      
      <section xml:id="dbdoclet.50569374_37877">
        <title>The Device Tree</title>
        
        <para>OF requires that the multiple instances of any device that appears
        more than once in the device tree must be distinguishable by means of
        their 
        <emphasis role="bold"><literal>&#8220;reg&#8221;</literal></emphasis> properties. The 
        <emphasis role="bold"><literal>&#8220;reg&#8221;</literal></emphasis> property must express the address
        of each node relative to its parent bus. Furthermore, the core
        specification says that the root node of the device tree usually
        represents the main physical bus of the system. Thus, if processors are
        not directly addressable on the main physical bus, as is expected to be
        the case on many/most PA-based systems, the CPU nodes on such systems may
        not be children of the root node but must instead be children of a
        pseudo-device node. In this case, the name of the pseudo-device node,
        which will usually be a child of the root node, shall be
        &#8220;cpus&#8221;.</para>
        <para>The &#8220;cpus&#8221; node shall have one child node of
        device_type &#8220;cpu&#8221; for each processor.</para>
        
      </section>
      
      <section xml:id="dbdoclet.50569374_18332">
        <title>Physical Address Formats and Representations for CPU
        Nodes</title>
        
        <para />
        
        <section>
          <title>Numerical Representation</title>
          <para>The numerical representation of a processor&#8217;s
          &#8220;address&#8221; in a LoPAR system shall consist of one cell,
          encoded as follows (Bit# 0 refers to the least significant bit)
          <emphasis role="bold">:</emphasis></para>
    
          <table frame="all" pgwide="1">
            <title>Numerical Representation of a Processor&#8217;s
            &#8220;address&#8221;</title>
            <?dbhtml table-width="75%" ?>
            <?dbfo table-width="75%" ?>
            <tgroup cols="5">
              <colspec colname="c1" colwidth="20*" align="center" />
              <colspec colname="c2" colwidth="20*" align="center" />
              <colspec colname="c3" colwidth="20*" align="center" />
              <colspec colname="c4" colwidth="20*" align="center" />
              <colspec colname="c5" colwidth="20*" align="center" />
              <thead>
                <row>
                  <entry valign="middle">
                    <para>
                      <emphasis role="bold">Bit#</emphasis>
                    </para>
                  </entry>
                  <entry>
                    <para>
                      <emphasis role="bold">33222222<?linebreak?>10987654</emphasis>
                    </para>
                  </entry>
                  <entry>
                    <para>
                      <emphasis role="bold">22221111<?linebreak?>32109876</emphasis>
                    </para>
                  </entry>
                  <entry>
                    <para>
                      <emphasis role="bold">11111100<?linebreak?>54321098</emphasis>
                    </para>
                  </entry>
                  <entry>
                    <para>
                      <emphasis role="bold">00000000<?linebreak?>76543210</emphasis>
                    </para>
                  </entry>
                </row>
              </thead>
              <tbody>
                <row>
                  <entry>
                    <para>phys.lo cell:</para>
                  </entry>
                  <entry>
                    <para>00000000</para>
                  </entry>
                  <entry>
                    <para>00000000</para>
                  </entry>
                  <entry>
                    <para>00000000</para>
                  </entry>
                  <entry>
                    <para>pppppppp</para>
                  </entry>
                </row>
              </tbody>
            </tgroup>
          </table>
          <para>where: 
          <emphasis>pppppppp</emphasis> is an 8-bit integer representing the
          interprocessor interrupt identifier used by the platform.</para>
          
        </section>
        
        <section>
          <title>Text Representation</title>
          
          <para>The text representation of a processor&#8217;s
          &#8220;address&#8221; shall be an ASCII hexadecimal number in the range 
          <emphasis>0...FF</emphasis>.</para>
          <para>Conversion of the hexadecimal number from text representation to
          numeric representation shall be case insensitive, and leading zeros shall
          be permitted but not required.</para>
          <para>Conversion from numeric representation to text representation shall
          use the lower case forms of the hexadecimal digits in the range 
          <emphasis>a..f</emphasis>, suppressing leading zeros.</para>
          
        </section>
        
        <section>
          <title>Unit Address Representation</title>
          
          <para>A processor&#8217;s &#8220;unit-number&#8221; (i.e. the first
          component of its 
          <emphasis role="bold"><literal>&#8220;reg&#8221;</literal></emphasis> value) is the interprocessor
          interrupt destination identifier used by the platform. For a
          uni-processor platform, the &#8220;unit-number&#8221; shall be
          zero.</para>
          
        </section>
      
      </section>
      
      <section xml:id="dbdoclet.50569374_25612">
        <title>CPUS Node Properties</title>
        
        <para>The following properties shall be created within the
        &#8220;cpus&#8221; node.</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;#address-cells&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis> to define the number of cells required
                to represent the physical addresses for the &#8220;
                <emphasis>cpu</emphasis> &#8221; nodes (i.e., the children of the &#8220;
                <emphasis>cpus</emphasis> &#8221; node).</para>
                <para><emphasis>prop-encoded-array</emphasis>: Integer constant 1, encoded as
                with <emphasis role="bold"><literal>encode-int</literal></emphasis>.</para>
                <para>The value of 
                <emphasis role="bold"><literal>&#8220;#address-cells&#8221;</literal></emphasis> for the
                &#8220;cpus&#8221; node shall be 
                <emphasis>1</emphasis>.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;#size-cells&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard 
                <emphasis>property name</emphasis> to define the number of cells necessary
                to represent the length of a physical address range.</para>
                <para><emphasis>prop-encoded-array</emphasis>: Integer constant 0, encoded as
                with <emphasis role="bold"><literal>encode-int</literal></emphasis>.</para>
                <para>The value of &#8220;
                <emphasis role="bold"><literal>#size-cells</literal></emphasis> &#8221; for the &#8220;cpus&#8221;
                pseudo-device node is 0 because the processors that are represented by
                the cpu nodes do not consume any physical address space.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>
        
      </section>
      
      <section xml:id="dbdoclet.50569374_89868">
        <title>CPU Node Properties</title>
        
        <para>For each CPU in the system, a cpu-node shall be defined as a child
        of 
        <emphasis role="bold"><literal>&#8220;cpus&#8221;</literal></emphasis>. The following properties apply to
        each of these nodes. The 
        <emphasis>cpus</emphasis> node shall not have &#8220;
        <emphasis>reg</emphasis> &#8221; or &#8220;
        <emphasis>ranges</emphasis> &#8221; properties. In general, properties in
        a cpu-node that affect the software interface (for example properties
        that convey the presence of instructions, presence of registers, or
        location of resources) to the processor are preserved by the device tree
        once presented upon boot. For a list of properties that may change before
        a reboot, see 
        <xref linkend="LoPAR.RTAS" />.</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;name&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>. The value of this property 
                shall be of the form: &#8220;PowerPC,&lt;name&gt;&#8221;, where &lt;name&gt; 
                is the name of the processor chip which may be displayed to the user.
                &lt;name&gt; 
                <emphasis>shall not</emphasis> contain underscores.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;device_type&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>. The value of this 
                property for CPU nodes shall be 
                <emphasis role="bold"><literal>&#8220;cpu&#8221;</literal></emphasis>.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;reg&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>proper name</emphasis> to define a cpu node&#8217;s
                unit-address.</para>
                <para><emphasis>prop-encoded-array</emphasis>: an integer encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>.</para>
                <para>For a cpu node, the first and only value of the 
                <emphasis role="bold"><literal>&#8220;reg&#8221;</literal></emphasis> property shall be the number of the
                per-processor interrupt line assigned to the processor represented by the
                node. For a uni-processor platform, the value of the 
                <emphasis role="bold"><literal>&#8220;reg&#8221;</literal></emphasis> property shall be zero.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;status&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>. The value of the is 
                property shall be one of the following string values:</para>
                
                <itemizedlist>		      
                  <listitem>
                    <para><emphasis role="bold"><literal>&#8220;okay&#8221;</literal></emphasis> 
                    for a good processor.</para>
                  </listitem>
                  
                  <listitem>
                    <para><emphasis role="bold"><literal>&#8220;fail&#8221;</literal></emphasis> 
                    for a processor that fails during power-on testing.</para>
                  </listitem>
                  
                  <listitem>
                    <para><emphasis role="bold"><literal>&#8220;fail-offline&#8221;</literal></emphasis> 
                    for a processor that has been automatically deconfigured because of previous 
                    failures.</para>
                  </listitem>
                  
                  <listitem>
                    <para><emphasis role="bold"><literal>&#8220;disabled&#8221;</literal></emphasis> 
                    for a processor that has been manually deconfigured.</para>
                  </listitem>
                </itemizedlist>		      
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;cpu-version&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Represents the processor type.</para>
                <para><emphasis>prop-encoded-value</emphasis>: The value, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                shall be either the value obtained by
                reading the Processor Version Register of the processor described by this
                node, or the logical processor version as given in 
                <xref linkend="dbdoclet.50569374_97612" />. The first byte of the logical
                processor version value shall be 0x0F. The values of the &#8220;Logical
                Processor Version&#8221; column of 
                <xref linkend="dbdoclet.50569374_97612" />indicate that the processor
                provides the base support described by that version of the architecture.
                The presence and value of all optional and implementation dependent
                features and facilities are described by their corresponding
                properties.</para>
          
                <table frame="all" pgwide="1" xml:id="dbdoclet.50569374_97612">
                  <title>Logical Processor Version Values</title>
                  <?dbhtml table-width="50%" ?>
                  <?dbfo table-width="50%" ?>
                  <tgroup cols="2">
                    <colspec colname="c1" colwidth="50*" align="center" />
                    <colspec colname="c2" colwidth="50*" align="center" />
                    <thead>
                      <row>
                        <entry>
                          <para>
                            <emphasis role="bold">Logical Processor Version</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Property Value</emphasis>
                          </para>
                        </entry>
                      </row>
                    </thead>
                    <tbody>
                      <row>
                        <entry>
                          <para>2.04</para>
                        </entry>
                        <entry>
                          <para>0x0F000001</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2.05</para>
                        </entry>
                        <entry>
                          <para>0x0F000002</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2.06</para>
                        </entry>
                        <entry>
                          <para>0x0F000003</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2.06 plus:</para>
                          <para>URG field in DSCR (Bits 55-57)</para>
                        </entry>
                        <entry>
                          <para>0x0F100003</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2.07</para>
                        </entry>
                        <entry>
                          <para>0x0F000004</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2.08</para>
                        </entry>
                        <entry>
                          <para>0x0F000005</para>
                        </entry>
                      </row>
                    </tbody>
                  </tgroup>
                </table>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;clock-frequency&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the internal processor speed (in hertz) of this node.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,extended-clock-frequency&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Property that represents the internal
                processor speed in hertz of this node. This property allows the encoding
                of multi-giga-hertz quantities.</para>
                <para><emphasis>prop-encoded-array</emphasis>: Consisting of the low order 32
                bits of two cells (freq-hi, freq-lo) each encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, such that 
                their combined value is (the low order 32 bits of freq-hi || the low order 
                32 bits of freq-lo).</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;timebase-frequency&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                that represents the rate (in hertz) at
                which the PA TimeBase and Decrementer registers are updated.</para>
                <para><emphasis role="bold">Note:</emphasis> The 601 PowerPC 
                processor does not have a timebase frequency,
                therefore on a 601 PowerPC processor the value reported in this property
                shall be 1 billion (1 x 109) which represents the logical rate of the
                real time clock.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,extended-timebase-frequency&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Property that represents the rate in
                hertz at which the PA TimeBase and Decrementer registers are updated.
                This property allows the encoding of multi-giga-hertz quantities.</para>
                <para><emphasis>prop-encoded-array</emphasis>: Consisting of the low order 32
                bits of two cells (freq-hi, freq-lo) each encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, such that their combined 
                value is (the low order 32 bits of freq-hi || the low order 32 bits of freq-lo).</para>
                <para><emphasis role="bold">Note:</emphasis> The 
                <emphasis role="bold"><literal>&#8220;ibm,extended-timebase-frequency&#8221;</literal></emphasis> 
                property will be deprecated from the architecture due to the emergence of the 
                <emphasis role="bold"><literal>&#8220;ibm,nominal-tbf&#8221;</literal></emphasis> property and the lack
                of a need for a two cell version of the 
                <emphasis role="bold"><literal>&#8220;timebase-frequency&#8221;</literal></emphasis> property.
                Implementations should not provide the 
                <emphasis role="bold"><literal>&#8220;ibm,extended-timebase-frequency&#8221;</literal></emphasis> property.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,nominal-tbf&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Property, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                that represents the design nominal
                timebase frequency (in hertz).</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,tbu40-offset&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: that provides the value that, when
                added (ignoring overflow) to the processor TimeBase, yields a value
                consistent with other platform partitions that utilize their respective
                values of the property. If the property is missing, the default value is
                zero.</para>
                <para><emphasis>prop-encoded-array</emphasis>: An eight byte, big endian,
                unsigned, binary value.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;64-bit&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node is a 64-bit implementation of the PA. The absence of
                this property indicates that the microprocessor defined by this CPU node
                is a 32 bit implementation of the PA</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;64-bit-virtual-address&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node supports the 64-bit virtual address subset of the 80-bit
                virtual address as defined by the PA. The absence of this property
                indicates that the PA processor defined by this CPU node supports the
                full 80-bit virtual address defined by the PA. This property is only
                valid for 64-bit implementations.</para>
                <para><emphasis role="bold">Note:</emphasis> The 
                <emphasis role="bold"><literal>&#8220;64-bit-virtual-address&#8221;</literal></emphasis> 
                will be
                deprecated from the architecture. Implementations should not provide this
                property.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;603-translation&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node uses the PowerPC 603 processor defined mechanism to
                update its Translation Lookaside Buffers (TLBs). The absence of this
                property indicates that the PA processor defined by this CPU node does
                not use the PowerPC 603 processor defined mechanism to update its
                TLBs.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;603-power-management&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node implements the PowerPC 603 processor defined power
                management states. The absence of this property indicates that the PA
                processor defined by this CPU node does not support the PowerPC 603
                processor defined power management states.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;bus-frequency&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                that represents the speed (in hertz) of
                this processor&#8217;s bus.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,extended-bus-frequency&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Property that represents the rate in
                hertz of this processor&#8217;s bus. This property allows the encoding of
                multi-giga-hertz quantities.</para>
                <para><emphasis>prop-encoded-array</emphasis>: Consisting of the low order 32
                bits of two cells (freq-hi, freq-lo) each encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                such that their combined value is (the
                low order 32 bits of freq-hi || the low order 32 bits of freq-lo).</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;32-64-bridge&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node implements the &#8220;Bridge Facilities and Instructions
                for 64-bit Implementations&#8221; as described in an appendix of Book III
                of 
                <xref linkend="dbdoclet.50569387_99718" />. The absence of this property
                indicates that the PA processor defined by this CPU node does not support
                these facilities and instructions.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;external-control&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node implements the External Control Facility as described in
                the &#8220;Optional Facilities and Instructions&#8221; appendix of Book
                II of 
                <xref linkend="dbdoclet.50569387_99718" />. The absence of his property
                indicates that the PA processor defined by this CPU node does not support
                the External Control Facility.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;general-purpose&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node implements the floating point instructions 
                <emphasis>fsqrt</emphasis>, 
                <emphasis>fsqrts</emphasis> and 
                <emphasis>stfiwx</emphasis>. The absence of this property indicates that
                the PA processor defined by this CPU node does not support the floating
                point instructions 
                <emphasis>fsqrt</emphasis>, 
                <emphasis>fsqrts</emphasis> and 
                <emphasis>stfiwx</emphasis>.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;reservation-granule-size&#8221;</literal></emphasis></term>
              <listitem>
                 <para>Standard property, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                that represents the reservation granule
                size (i.e., the minimum size of lock variables) supported by this
                processor, in bytes.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;graphics&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node implements floating point instructions 
                <emphasis>fres, frsqrte,</emphasis> and
                <emphasis>fsel</emphasis>. The absence of this property indicates that
                the PA processor defined by this CPU node does not support the floating
                point instructions 
                <emphasis>fres, frsqrte,</emphasis> and
                <emphasis>fsel.</emphasis></para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;performance-monitor&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates that the processor described
                by this node implements a performance monitor.</para>
                <para><emphasis>prop-encoded-array</emphasis>: Consists of a pair of values,
                each encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>. 
                The first value of the pair shall be 0
                indicating that the performance monitor functionality is implementation
                specific. The second value of the pair represents the documentation
                describing the performance monitor functionality implemented by the
                processor described by this node. The documentation represented by the
                second value is specified in 
                <xref linkend="dbdoclet.50569374_84889" />.</para>
          
                <table frame="all" pgwide="1" xml:id="dbdoclet.50569374_84889">
                  <title>Documentation for Implementation Specific Performance
                  Monitors</title>
                  <?dbhtml table-width="50%" ?>
                  <?dbfo table-width="50%" ?>
                  <tgroup cols="2">
                    <colspec colname="c1" colwidth="50*" align="center" />
                    <colspec colname="c2" colwidth="50*" align="center" />
                    <thead>
                      <row>
                        <entry>
                          <para>
                            <emphasis role="bold">Second Value</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Documentation</emphasis>
                          </para>
                        </entry>
                      </row>
                    </thead>
                    <tbody>
                      <row>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis>Power 5+ Performance Monitor Programmer&#8217;s
                            Guide</emphasis>
                          </para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis>Power 7 Performance Monitor Programmer&#8217;s
                            Guide</emphasis>
                          </para>
                        </entry>
                      </row>
                    </tbody>
                  </tgroup>
                </table>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,vmx&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis> that indicates that the processor
                supports the POWER VMX architecture.</para>
                <para><emphasis>prop-encoded-array</emphasis>: an integer encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                that represents the level of the VMX
                architecture supported. The first level supported is the value 1. The
                value of 1 represents the level of support described by the 
                <emphasis>A Vector/SIMD Multimedia eXtension to the PowerPC Architecture,
                Specification Revision 1.2.3, 7/18/97</emphasis> specification. The value
                of 2 represents the level of support provided by the VSX option of 
                <xref linkend="dbdoclet.50569387_99718" />level 2.06.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,segment-page-sizes&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: that indicates the segment base page
                sizes and related encodings supported by the processor.</para>
                <para><emphasis>prop-encoded-array</emphasis>: one or more
                segment-page-size-descriptor(s).</para>
                <para><emphasis>segment-page-size-descriptor</emphasis>: a
                segment-page-size-header followed by a pte-lp-descriptor.</para>
                <para><emphasis>segment-page-size-header</emphasis>: Consists of three cells
                (X,Y,Z) encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>. 
                The first cell represents the base page
                size of the segment (the page size which determines the hash value used
                to locate the segment's page table entries) as 2
                <emphasis>X</emphasis>. The second cell contains the SLB encoding that,
                ORed with the RS register value for use by a slbmte instruction, selects
                this segment's base page size. Note, the low order bits of the cell Y are
                aligned with the low order bits of RS and the RS's L and LP bits are zero
                prior to the logical OR operation. The third cell contains the number of
                pte-lp-encodings in the pte-lp-descriptor.</para>
                <para><emphasis>pte-lp-descriptor</emphasis>: Consists of Z (from the
                segment-page-size-header) pte-lp-encoding(s), one for each of the page
                sizes supported for this base segment page size.</para>
                <para><emphasis>pte-lp-encoding</emphasis>: Each pte-lp-encoding consists of
                two cells (P,Q) encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>. 
                The first cell represents the page size
                of the encoding as 2
                <emphasis>P</emphasis> (thus implying the number of low order RPN bits
                that are available to page size encoding). The second cell, left shifted
                12 bit positions, is the encoding to be entered into the available low
                order RPN bits to represent this page size for this segment base page
                size.</para>
                <para><emphasis role="bold">Note:</emphasis> A 
                <emphasis>segment-page-size-descriptor</emphasis> applies to a segment
                only if the size of the segment is greater than or equal to all of the
                page sizes within the 
                <emphasis>pte-lp-encoding</emphasis> (s) contained within the 
                <emphasis>segment-page-size-descriptor</emphasis>.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,processor-page-sizes&#8221;</literal></emphasis></term>
              <listitem>
                <para>property name: Relates the number and sizes of the virtual memory
                page sizes supported by the processor describe by this node.</para>
                <para><emphasis>prop-encoded-array</emphasis>: One to N cells in ascending
                value order, each encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, each cell represents the size of a
                supported virtual memory page where the value of the cell is the power of
                2 of the cell size. i.e. a 4 K page size is represented by the value 12
                (4 K= 2
                <superscript>12</superscript>) etc.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,processor-segment-sizes&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Relates the number and sizes of the
                virtual memory segment sizes supported by the processor described by this
                node.</para>
                <para><emphasis>prop-encoded-array</emphasis>: One to N cells in ascending
                value order of the segment selector (SLBE B field), each encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, each positive value cell represents the
                size of a supported virtual memory segment where the value of the cell is
                the power of 2 of the segment size. That is, a 256Meg segment size is
                represented by the value 28 (256Meg = 2
                <superscript>28</superscript>) etc. (negative valued cells represent
                unsupported encodings).</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,processor-storage-keys&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis> indicating the number of virtual
                storage keys supported by the processor described by this node.</para>
                <para><emphasis>prop-encoded-array</emphasis>: Consists of two cells encoded as
                with <emphasis role="bold"><literal>encode-int</literal></emphasis>. 
                The first cell represents the number of
                virtual storage keys supported for data accesses while the second cell
                represents the number of virtual storage keys supported for instruction
                accesses. The cell value of zero indicates that no storage keys are
                supported for the access type.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,processor-vadd-size&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis> indicating the number of virtual
                address bits that are supported by the processor described by this
                node.</para>
                <para><emphasis>prop-encode-array</emphasis>: An integer, encoded as with 
                <emphasis>encode-int,</emphasis> that represents the number of supported
                virtual address bits.</para>
                <para><emphasis role="bold">Note:</emphasis> A processor 
                described by this node implements
                the least significant 
                <emphasis role="bold"><literal>&#8220;ibm,processor-vadd-size&#8221;</literal></emphasis> 
                bits of the architected virtual address.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,vrma-page-sizes&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property-name</emphasis>: Maps the VRMASD field values
                implemented by the processor described by this node to their page
                sizes.</para>
                <para><emphasis>prop-encoded-array</emphasis>: Array of one or more 
                <emphasis>VRMA page-size-descriptor</emphasis> (s) starting with the value
                selected by the firmware when booting the partition, followed by the
                other values supported by the platform.</para>
                <para><emphasis>VRMA page-size-descriptor</emphasis>: A pair of cells encoded
                as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>; The first cell is the log base 2 of the
                page size. The second cell contains, in its low order bits, the VRMASD
                field value to achieve that supported size. The high order bits of the
                second cell are zero.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,estimate-precision&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Relates PA estimate instruction
                mnemonics to precisions supported by the processor described by this
                node.</para>
                <para><emphasis>prop-encoded-array</emphasis>: One or more 
                <emphasis>instruction-precision descriptor</emphasis> (s).</para>
                <para>
                <emphasis>instruction-precision descriptor</emphasis>: An 
                <emphasis>instruction descriptor</emphasis> followed by a 
                <emphasis>precision descriptor</emphasis>. An 
                <emphasis>instruction-precision</emphasis> descriptor relates one estimate
                instruction mnemonic to the precision supported by the processor
                described by this node for that estimate instruction mnemonic.</para>
                <para><emphasis>instruction descriptor</emphasis>: Consists of one PA
                instruction mnemonic encoded as with 
                <emphasis role="bold"><literal>encode-string</literal></emphasis>.</para>
                <para><emphasis>precision descriptor</emphasis>: Consists of an integer, encoded
                as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                specifying the number of bits of
                precision the processor described by this node supports for an
                instruction mnemonic.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,dfp&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates that the processor described
                by this node supports the Decimal Floating Point (DFP)
                architecture.</para>
                <para><emphasis>prop-encoded-value</emphasis>: an integer, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                that represents the level of DFP support
                of the CPU described by this node. The absolute value of the integer
                represents the level of the DFP architecture supported. The sign of the
                integer indicates how the architecture level is supported. A positive
                integer indicates native support while a negative integer indicates
                emulation assisted support. The absolute values supported are as
                follows:</para>
                <para>1: Represents the level of support defined by Version 2.05 of the 
                <xref linkend="dbdoclet.50569387_99718" />.</para>
                <para>2: Represents the level of support defined by Version 2.06 of the 
                <xref linkend="dbdoclet.50569387_99718" />.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,purr&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates that the processor
                described by this node implements a Processor Utilization of Resources
                Register (PURR).</para>
                <para><emphasis>prop-encoded-value</emphasis>: an integer, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                that represents the level of PURR
                architecture supported. The first level supported is the value 1 and is
                defined by Section 6.5 &#8220;Processor Utilization of Resources
                Register&#8221; of Book III of version 2.02 of the PA.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,spurr&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates that the processor
                described by this node implements a Scaled Processor Utilization of
                Resources Register (SPURR).</para>
                <para><emphasis>prop-encoded-value</emphasis>: an integer, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, 
                that represents the level of SPURR
                architecture supported. The value of 1 represents the level of support
                defined by Version 2.05 of the 
                <xref linkend="dbdoclet.50569387_99718" />.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,pa-features&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates level of support of several
                extended features of the Processor Architecture.</para>
                <para><emphasis>prop-encoded-array</emphasis>: One or more 
                <emphasis>attribute-descriptor</emphasis> (s).</para>
                <para><emphasis>attribute-descriptor</emphasis>: Consists of an 
                <emphasis>attribute-header</emphasis> immediately followed by an 
                <emphasis>attribute-specifier.</emphasis></para>
                <para><emphasis>attribute-header</emphasis>: Consists of two bytes. The first
                byte is an unsigned integer representing a value from 1 to 254. The first
                byte specifies the number of bytes implemented by the platform of the 
                <emphasis>attribute-specifier</emphasis>. The second byte is an unsigned
                integer specifying the 
                <emphasis>attribute-specifier-type</emphasis>.</para>
                <para><emphasis>attribute-specifier</emphasis>: The 
                <emphasis>attribute-specifier</emphasis> is defined by the 
                <emphasis>attribute-specifier-type</emphasis> of the 
                <emphasis>attribute-header.</emphasis> The 
                <emphasis>attribute-specifier</emphasis> for the 
                <emphasis>attribute-specifier-type</emphasis> value of 0 is defined by 
                <xref linkend="dbdoclet.50569374_18997" />.</para>
          
                <table frame="all" pgwide="1" xml:id="dbdoclet.50569374_18997">
                  <title>Definition for 
                  <emphasis>attribute-specifier</emphasis>
                  <emphasis>attribute-specifier-type</emphasis> value 0</title>
                  <tgroup cols="4">
                    <colspec colname="c1" colwidth="20*" align="center" />
                    <colspec colname="c2" colwidth="10*" align="center" />
                    <colspec colname="c3" colwidth="20*" align="center" />
                    <colspec colname="c4" colwidth="50*" align="center" />
                    <thead>
                      <row>
                        <entry>
                          <para>
                            <emphasis role="bold">Byte Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Bit Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Attribute Name</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Description</emphasis>
                          </para>
                        </entry>
                      </row>
                    </thead>
                    <tbody>
                      <row>
                        <entry morerows="7">
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>Memory Management Unit (MMU)</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates MMU support; else not
                          supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>Floating Point Unit (FPU)</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates FPU support; else not
                          supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2</para>
                        </entry>
                        <entry>
                          <para>Segment Lookaside Buffer (SLB).</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates SLB support; else not
                          supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>3</para>
                        </entry>
                        <entry>
                          <para>RUN field</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates support for the RUN field of the
                          Control Register (CTRL, SPR #152); else not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>4</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>5</para>
                        </entry>
                        <entry>
                          <para>Data Address Breakpoint Register (DABR)</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates DABR support; else not
                          supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>6</para>
                        </entry>
                        <entry>
                          <para>No Execute (N) bit in Page Table Entries.</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates No Execute (N) bit in Page Table
                          Entry support; else not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>7</para>
                        </entry>
                        <entry>
                          <para>Write Through Required (W) bit</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates setting the W bit to 1 (write
                          through always) is supported; else attempting to set the W bit
                          to 1 has no effect</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="7">
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>Memory Coherence Required (M) bit</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that setting the M bit to 0
                          (main storage not always coherent) is supported; else
                          attempting to set the M bit to 0 has no effect.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>Data Storage Interrupt Status Register (DSISR) set on an
                          alignment interrupt.</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the DSISR is set on an
                          alignment interrupt as described by version 2.01 of PA; else
                          the DSISR is not set on alignment interrupt as described by
                          version 2.01 of PA.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2</para>
                        </entry>
                        <entry>
                          <para>I=1 (cache inhibited) Large Pages</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates support for I=1 (cache
                          inhibited) large pages; else not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>3</para>
                        </entry>
                        <entry>
                          <para>Round to Integer (from floating point) group of
                          instructions.</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates support for the 
                          <emphasis>frin, friz, frip,</emphasis> and 
                          <emphasis>frim</emphasis> instructions; else these instructions
                          are not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>4</para>
                        </entry>
                        <entry>
                          <para>Data Address Breakpoint Register Extension (DABRX)</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates support for the DABRX
                          architecture as defined by version 2.02 of PA; else not
                          supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>5</para>
                        </entry>
                        <entry>
                          <para>User Accessible SPRG3</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates support for accessing SPRG3 in
                          Problem State; else SPRG3 is not accessible in Problem
                          State.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>6</para>
                        </entry>
                        <entry>
                          <para>Reading an invalid SLB entry returns zeros.</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that reading an invalid SLB
                          entry always returns zeros; else non-zero values may be
                          returned.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>7</para>
                        </entry>
                        <entry>
                          <para>Support for &#8220;110&#8221; value of the Page
                          Protection (PP) bits.</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates support for &#8220;110&#8221;
                          value of the Page Protection (PP) bits as described by version
                          2.04 of PA; else &#8220;110&#8221; is not supported.as
                          described by 2.04 of PA.</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="7">
                          <para>2</para>
                        </entry>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>Virtualized Partition Memory (VPM)</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates support for Virtualized
                          Partition Memory (VPM) as described by version 2.04 of PA; else
                          not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>2.05 Data Stream Support</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that data streams as described
                          by version 2.05 of PA are supported; else not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>3</para>
                        </entry>
                        <entry>
                          <para>Data Address Register (DAR) set on an alignment
                          interrupt.</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the DAR is set on an
                          alignment interrupt as described by version 2.01 of PA; else
                          the DAR is not set on alignment interrupt as described by
                          version 2.01 of PA.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>4</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>5</para>
                        </entry>
                        <entry>
                          <para>Program Priority Register (PPR)</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the PPR is implemented as
                          described by version 2.03 of PA; else the PPR is not
                          implemented as described by version 2.03 of PA.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>6</para>
                        </entry>
                        <entry>
                          <para>2.02 Data Stream Support</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that data streams as described
                          by version 2.02 of PA are supported; else not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>7</para>
                        </entry>
                        <entry>
                          <para>2.06 Data Stream Support</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that data streams as described
                          by version 2.06 of PA are supported; else the 2.06 version data
                          streams are not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="2">
                          <para>3</para>
                        </entry>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>LSD in DSCR(Bit 58)</para>
                        </entry>
                        <entry>
                          <para>The value of 1indicates that &#8220;Load Stream
                          Disable&#8221; bit of the Data Stream Control Register is
                          implemented</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>URG in DSCR (Bits 55::57)</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the &#8220;Depth Attainment
                          Urgency&#8221; field of the Data Stream Control Register is
                          implemented.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="2">
                          <para>4</para>
                        </entry>
                        <entry nameend="c3" namest="c2">
                          <para>Storage Order Options</para>
                        </entry>
                        <entry>
                          <para>Byte bits define the availability of specific
                          options</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>2.06 Strong Storage Order</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that Strong Storage Order as
                          defined by version 2.06 of PA is supported; else not.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-7</para>
                        </entry>
                        <entry>
                          <para>Reserved for future storage order options</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="4">
                          <para>5</para>
                        </entry>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>Little Endian</para>
                        </entry>
                        <entry>
                          <para>The value of 1indicates support for Little Endian as
                          described by version 2.03 of PA; else not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>Come From Address Register (CFAR)</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the CFAR is implemented as
                          described by version 2.05 of PA; else the CFAR is not
                          implemented as described by version 2.05 of PA.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2</para>
                        </entry>
                        <entry>
                          <para>Elemental Barriers</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that elemental barriers are
                          supported; else elemental barriers are not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>3</para>
                        </entry>
                        <entry>
                          <para>2.07 load/store quadword</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the load/store quadword
                          category as described by version 2.07 of POWER ISA is
                          supported; else the 2.07 version load/store quadword category
                          is not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>4-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="2">
                          <para>6-7</para>
                        </entry>
                        <entry nameend="c4" namest="c2">
                          <para>Data Streaming Specifications</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>2.07 Data Streaming Support</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that data streams as described
                          by version 2.07 of POWER ISA are supported; else the 2.07
                          version data streams are not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>8-15</para>
                        </entry>
                        <entry>
                          <para>0-7</para>
                        </entry>
                        <entry>
                          <para>Reserved Co-Processor Option</para>
                        </entry>
                        <entry>
                          <para>Individual non-zero bits indicate available coprocessor
                          types per their architected ACOP bit locations. (the value
                          0x0000000000000000 indicates that moving to/from the ACOP SPR
                          or the ICSWX instruction should not be attempted)</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="2">
                          <para>16-17</para>
                        </entry>
                        <entry nameend="c4" namest="c2">
                          <para>Level of Vector Category Support</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>2.07 Vector Support</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the vector category as
                          described by version 2.07 of POWER ISA is supported; else the
                          2.07 version vector category is not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="2">
                          <para>18-19</para>
                        </entry>
                        <entry nameend="c4" namest="c2">
                          <para>Level of Vector Scalar Category Support</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>2.07 Vector Scalar Support</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the vector scalar category
                          as described by version 2.07 of POWER ISA is supported; else
                          the 2.07 version vector scalar category is not
                          supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="2">
                          <para>20-21</para>
                        </entry>
                        <entry nameend="c4" namest="c2">
                          <para>Level of Vector.XOR Category Support</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>2.07 Vector.XOR Support</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the vector.xor category as
                          described by version 2.07 of POWER ISA is supported; else the
                          2.07 version vector.xor category is not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry morerows="2">
                          <para>22-23</para>
                        </entry>
                        <entry nameend="c4" namest="c2">
                          <para>Level of Transactional Memory Category Support</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>2.07 Transactional Memory Support</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the Transactional Memory
                          Category as described by version 2.07 of POWER ISA is
                          supported; else the 2.07 version Transactional Memory Category
                          is not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>24-255</para>
                        </entry>
                        <entry>
                          <para>0-7</para>
                        </entry>
                        <entry>
                          <para>Undefined</para>
                        </entry>
                        <entry>
                          <para>Readers 
                          <emphasis>shall</emphasis> ignore undefined bytes if
                          present.</para>
                        </entry>
                      </row>
                    </tbody>
                  </tgroup>
                </table>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,pi-features&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates level of support of
                processor implementation specific options not described by the Processor
                Architecture.</para>
                <para><emphasis>prop-encoded-array</emphasis>: One or more 
                <emphasis>pi-attribute-descriptor</emphasis> (s).</para>
                <para><emphasis>pi-attribute-descriptor</emphasis>: Consists of a 
                <emphasis>pi-attribute-header</emphasis> immediately followed by a 
                <emphasis>pi-attribute-specifier.</emphasis></para>
                <para><emphasis>pi-attribute-header</emphasis>: Consists of two bytes. The first
                byte is an unsigned integer representing a value from 1 to 254. The first
                byte specifies the number of bytes implemented by the platform of the 
                <emphasis>pi-attribute-specifier</emphasis>. The second byte is an
                unsigned integer specifying the 
                <emphasis>pi-attribute-specifier-type</emphasis>.</para>
                <para><emphasis>pi-attribute-specifier</emphasis>: The 
                <emphasis>pi-attribute-specifier</emphasis> is defined by the 
                <emphasis>pi-attribute-specifier-type</emphasis> of the 
                <emphasis>pi-attribute-header.</emphasis> The 
                <emphasis>pi-attribute-specifier</emphasis> for the 
                <emphasis>pi-attribute-specifier-type</emphasis> value of 0 is defined by 
                <xref linkend="dbdoclet.50569374_22443" />.</para>
          
                <table frame="all" pgwide="1" xml:id="dbdoclet.50569374_22443">
                  <title>Definition for 
                  <emphasis>&#8216;</emphasis>
                  <emphasis>pi-attribute-specifier-type</emphasis> value 0</title>
                  <tgroup cols="4">
                    <colspec colname="c1" colwidth="20*" align="center" />
                    <colspec colname="c2" colwidth="10*" align="center" />
                    <colspec colname="c3" colwidth="20*" align="center" />
                    <colspec colname="c4" colwidth="50*" align="center" />
                    <thead>
                      <row>
                        <entry>
                          <para>
                            <emphasis role="bold">Byte Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Bit Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Attribute Name</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Description</emphasis>
                          </para>
                        </entry>
                      </row>
                    </thead>
                    <tbody>
                      <row>
                        <entry morerows="3">
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>P4 Data Address Register (DAR) setting on alignment
                          interrupt.</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the DAR is set on an
                          alignment interrupt as described by version 2.01 of PA except
                          for the case where the interrupt is caused by an unsupported
                          access to cache inhibited space. In this case, the DAR will be
                          set to the effective address of the first access into the cache
                          inhibited space. The value of 0 indicates that the processor
                          does not adhere to this behavior.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2</para>
                        </entry>
                        <entry>
                          <para>Ordered Thread Activation/Deactivation</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the 
                          <emphasis role="bold"><literal>&#8220;ibm,ppc-interrupt-server-#s&#8221;</literal></emphasis> property
                          conveys the order that threads need to be activated and
                          deactivated in to achieve optimal performance; else no need to
                          activate and deactivate threads in order.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>3-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-255</para>
                        </entry>
                        <entry>
                          <para>0-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                    </tbody>
                  </tgroup>
                </table>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,negotiated-pa-features&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates level 
                of support negotiated via the 
                <emphasis role="bold"><literal>ibm,client-architecture-support</literal></emphasis> 
                method (See 
                <xref linkend="dbdoclet.50569368_91814" />) of several extended features
                of the Processor Architecture.</para>
                <para><emphasis>prop-encoded-array</emphasis>: One or more 
                <emphasis>negotiated-pa-attribute-descriptor</emphasis> (s).</para>
                <para><emphasis>negotiated-pa-attribute-descriptor</emphasis>: Consists of a 
                <emphasis>negotiated-pa-attribute-header</emphasis> immediately followed
                by a 
                <emphasis>negotiated-pa-attribute-specifier.</emphasis></para>
                <para><emphasis>negotiated-pa-attribute-header</emphasis>: Consists of two
                bytes. The first byte is an unsigned integer representing a value from 1
                to 254. The first byte specifies the number of bytes implemented by the
                platform of the 
                <emphasis>negotiated-pa-attribute-specifier</emphasis>. The second byte
                is an unsigned integer specifying the 
                <emphasis>negotiated-pa-attribute-specifier-type</emphasis>.</para>
                <para><emphasis>negotiated-pa-attribute-specifier</emphasis>: The 
                <emphasis>negotiated-pa-attribute-specifier</emphasis> is defined by the 
                <emphasis>negotiated-pa-attribute-specifier-type</emphasis> of the 
                <emphasis>negotiated-pa-attribute-header.</emphasis> The 
                <emphasis>negotiated-pa-attribute-specifier</emphasis> for the 
                <emphasis>negotiated-pa-attribute-specifier-type</emphasis> value of 0 is
                defined by 
                <xref linkend="dbdoclet.50569374_79508" />.</para>
          
                <table frame="all" pgwide="1" xml:id="dbdoclet.50569374_79508">
                  <title>Definition for 
                  <emphasis>negotiated-pa-attribute-specifier</emphasis>
                  <emphasis>negotiated-pa-attribute-specifier-type</emphasis> value
                  0</title>
                  <tgroup cols="4">
                    <colspec colname="c1" colwidth="20*" align="center" />
                    <colspec colname="c2" colwidth="10*" align="center" />
                    <colspec colname="c3" colwidth="20*" align="center" />
                    <colspec colname="c4" colwidth="50*" align="center" />
                    <thead>
                      <row>
                        <entry>
                          <para>
                            <emphasis role="bold">Byte Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Bit Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Attribute Name</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Description</emphasis>
                          </para>
                        </entry>
                      </row>
                    </thead>
                    <tbody>
                      <row>
                        <entry morerows="1">
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>TC Set</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the TC bit is implemented
                          as described by version 2.05 of PA and set to a value of 1;
                          else the TC bit is not implemented as described by version 2.05
                          of PA or not set to a value of 1.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-255</para>
                        </entry>
                        <entry>
                          <para>0-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                    </tbody>
                  </tgroup>
                </table>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,raw-pi-features&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates level of support of
                processor implementation specific options not described by the Processor
                Architecture and not supported on partitions that contain the 
                <emphasis role="bold"><literal>&#8220;ibm,migratable-partition&#8221;</literal></emphasis> property.</para>
                <para><emphasis>prop-encoded-array</emphasis>: One or more 
                <emphasis>raw-pi-attribute-descriptor</emphasis> (s).</para>
                <para><emphasis>raw-pi-attribute-descriptor</emphasis>: Consists of a 
                <emphasis>raw-pi-attribute-header</emphasis> immediately followed by a 
                <emphasis>raw-pi-attribute-specifier.</emphasis></para>
                <para><emphasis>raw-pi-attribute-header</emphasis>: Consists of two bytes. The
                first byte is an unsigned integer representing a value from 1 to 254. The
                first byte specifies the number of bytes implemented by the platform of
                the 
                <emphasis>raw-pi-attribute-specifier</emphasis>. The second byte is an
                unsigned integer specifying the 
                <emphasis>raw-pi-attribute-specifier-type</emphasis>.</para>
                <para><emphasis>raw-pi-attribute-specifier</emphasis>: The 
                <emphasis>raw-pi-attribute-specifier</emphasis> is defined by the 
                <emphasis>raw-pi-attribute-specifier-type</emphasis> of the 
                <emphasis>raw-pi-attribute-header.</emphasis> The 
                <emphasis>raw-pi-attribute-specifier</emphasis> for the 
                <emphasis>raw-pi-attribute-specifier-type</emphasis> value of 0 is defined
                by 
                <xref linkend="dbdoclet.50569374_66103" />.</para>
          
                <table frame="all" pgwide="1" xml:id="dbdoclet.50569374_66103">
                  <title>Definition for 
                  <emphasis>raw-pi-attribute-specifier</emphasis>
                  <emphasis>raw-pi-attribute-specifier-type</emphasis> value 0</title>
                  <tgroup cols="4">
                    <colspec colname="c1" colwidth="20*" align="center" />
                    <colspec colname="c2" colwidth="10*" align="center" />
                    <colspec colname="c3" colwidth="20*" align="center" />
                    <colspec colname="c4" colwidth="50*" align="center" />
                    <thead>
                      <row>
                        <entry>
                          <para>
                            <emphasis role="bold">Byte Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Bit Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Attribute Name</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Description</emphasis>
                          </para>
                        </entry>
                      </row>
                    </thead>
                    <tbody>
                      <row>
                        <entry morerows="1">
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>FPR GPR Move Instructions</para>
                        </entry>
                        <entry>
                          <para>The value of 1 indicates that the PA processor defined by
                          this CPU node implements the 
                          <emphasis>mftgpr</emphasis> and 
                          <emphasis>mffgpr</emphasis> instructions as described by IBM 
                          <emphasis>POWER6&#174; CEC Book IV Implementation
                          Features</emphasis>; else not supported.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1-255</para>
                        </entry>
                        <entry>
                          <para>0-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                    </tbody>
                  </tgroup>
                </table>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;ibm,pa-optimizations&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>: Indicates the level of support of
                performance variabilities described by the Processor Architecture.</para>
                <para><emphasis>prop-encoded-array</emphasis>: One or more 
                <emphasis>pa-optimization-attribute-descriptor</emphasis> (s).</para>
                <para><emphasis>pa-optimization-attribute-descriptor</emphasis>: Consists of a 
                <emphasis>pa-optimization-attribute-header</emphasis> immediately followed
                by a 
                <emphasis>pa-optimization-attribute-specifier.</emphasis></para>
                <para><emphasis>pa-optimization-attribute-header</emphasis>: Consists of two
                bytes. The first byte is an unsigned integer representing a value from 1
                to 254. The first byte specifies the number of bytes implemented by the
                platform of the 
                <emphasis>pa-optimization-attribute-specifier</emphasis>. The second byte
                is an unsigned integer specifying the 
                <emphasis>pa-optimization-attribute-specifier-type</emphasis>.</para>
                <para><emphasis>pa-optimization-attribute-specifier</emphasis>: The 
                <emphasis>pa-optimization-attribute-specifier</emphasis> is defined by the
                <emphasis>pa-optimization-attribute-specifier-type</emphasis> of the 
                <emphasis>pa-optimization-attribute-header.</emphasis> The 
                <emphasis>pa-optimization-attribute-specifier</emphasis> for the 
                <emphasis>pa-optimization-attribute-specifier-type</emphasis> value of 0
                is defined by 
                <xref linkend="dbdoclet.50569374_95694" />.</para>
          
                <table frame="all" pgwide="1" xml:id="dbdoclet.50569374_95694">
                  <title>Definition for 
                  <emphasis>pa-optimization-attribute-specifier</emphasis>
                  <emphasis>pa-optimization-attribute-specifier-type</emphasis> value
                  0</title>
                  <tgroup cols="4">
                    <colspec colname="c1" colwidth="20*" align="center" />
                    <colspec colname="c2" colwidth="10*" align="center" />
                    <colspec colname="c3" colwidth="20*" align="center" />
                    <colspec colname="c4" colwidth="50*" align="center" />
                    <thead>
                      <row>
                        <entry>
                          <para>
                            <emphasis role="bold">Byte Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Bit Number</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Attribute Name</emphasis>
                          </para>
                        </entry>
                        <entry>
                          <para>
                            <emphasis role="bold">Description</emphasis>
                          </para>
                        </entry>
                      </row>
                    </thead>
                    <tbody>
                      <row>
                        <entry>
                          <para>0</para>
                        </entry>
                        <entry>
                          <para>0-7</para>
                        </entry>
                        <entry>
                          <para>Stream IDs</para>
                        </entry>
                        <entry>
                          <para>The value is an unsigned quantity indicating the number
                          of data stream IDs supported. The value of this byte 
                          <emphasis>shall</emphasis> be zero for processors that do not
                          support data streams.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>1</para>
                        </entry>
                        <entry>
                          <para>0-7</para>
                        </entry>
                        <entry>
                          <para>Default Prefetch Depth</para>
                        </entry>
                        <entry>
                          <para>The value in the Default Prefetch Depth (DPFD) field of
                          the Logical Partitioning Control Register (LPCR) as described
                          by version 2.05 of PA. Unimplemented high order bits 
                          <emphasis>shall</emphasis> be zero. This byte is valid only if
                          the &#8220;2.05 Data Stream Support&#8221; bit of 
                          <emphasis role="bold"><literal>&#8220;ibm,pa-features&#8221;</literal></emphasis> is set to
                          one; else this byte is undefined.</para>
                        </entry>
                      </row>
                      <row>
                        <entry>
                          <para>2-255</para>
                        </entry>
                        <entry>
                          <para>0-7</para>
                        </entry>
                        <entry>
                          <para>Reserved</para>
                        </entry>
                        <entry>
                          <para>Reserved bits within defined bytes 
                          <emphasis>shall</emphasis> be zero.</para>
                        </entry>
                      </row>
                    </tbody>
                  </tgroup>
                </table>
              </listitem>
  			  </varlistentry>
        </variablelist>
        
      </section>
      
      <section xml:id="dbdoclet.50569374_58783">
        <title>TLB properties</title>
        
        <para>Since the PA defines the MMU as being part of the processor, the
        properties defined by Section 3.6.5 of 
        <xref linkend="dbdoclet.50569387_45524" />and the following MMU-related
        properties shall be presented under &#8220;cpu&#8221; nodes.</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;tlb-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the total number of TLB entries.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;tlb-sets&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the number of associativity sets of the TLB. A value of 1 indicates that the TLB is
                fully-associative.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;tlb-split&#8221;</literal></emphasis></term>
              <listitem>
                <para>This property, if present, shall indicate that the TLB has a split
                organization. The absence of this property shall indicate that the TLB
                has a unified organization.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;d-tlb-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the total number of d-TLB entries.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;d-tlb-sets&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the number of associativity sets of the d-TLB. A value of 1 indicates that the 
                d-TLB is fully-associative.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;i-tlb-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that 
                represents the total number of i-TLB entries.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;i-tlb-sets&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the number of associativity sets of the i-TLB. A value of 1 indicates that the 
                i-TLB is fully-associative.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;tlbia&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>prop-encoded-array</emphasis>: &lt;none&gt;</para>
                <para>This property, if present, indicates that the PA processor defined
                by this CPU node implements the<emphasis>tlbia</emphasis> instruction. The absence 
                of this property indicates that the PA processor defined by this CPU node does 
                not support the <emphasis>tlbia</emphasis> instruction.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>
        
      </section>
      
      <section>
        <title>Internal (L1) cache properties</title>
        
        <para>The PA defines a Harvard-style cache architecture; however, unified
        caches are an implementation option. All of the PA cache instructions act
        upon a cache &#8220;block&#8221;. The coherence block size, if different
        from the cache block size, is reported via the 
        <emphasis role="bold"><literal>&#8220;i-cache-line-size&#8221;</literal></emphasis> and 
        <emphasis role="bold"><literal>&#8220;d-cache-line-size&#8221;</literal></emphasis> properties. The
        internal (also referred to as &#8220;L1&#8221;) caches of PA processors
        are represented in the OF device tree by the following properties
        contained under 
        <emphasis role="bold"><literal>&#8220;cpu&#8221;</literal></emphasis> nodes.</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;cache-unified&#8221;</literal></emphasis></term>
              <listitem>
                <para>This property, if present, indicates that the internal cache has a
                physically unified organization. Absence of this property indicates that
                the internal caches are implemented as separate instruction and data
                caches. Unless otherwise noted, separate instruction and data caches
                require the architected instruction sequence for instruction modification
                so that data cache stores appear in the instruction cache.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;i-cache-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the total size (in bytes) of the internal instruction cache.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;i-cache-sets&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                number of associativity sets of the internal instruction cache. A value of 1 
                signifies that the instruction cache is fully associative.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;i-cache-block-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the internal instruction cache's block size, in bytes.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;d-cache-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the total size (in bytes) of the internal data cache.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;d-cache-sets&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                number of associativity sets of the internal data cache. A value of 1 signifies 
                that the data cache is fully associative.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;d-cache-block-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the internal (L1) data cache's block size, in bytes.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;l2-cache&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the next level of cache in the memory hierarchy.</para>
                <para>Absence of this property indicates that no further levels of cache
                are present. If present, its value is the 
                <emphasis>phandle</emphasis> of the device node that represents the next
                level of cache.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;i-cache-line-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the internal instruction cache's coherency block size (line size), in bytes, 
                if different than its cache block size.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;d-cache-line-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents 
                the internal data cache's coherency block size (line size), in bytes, if different 
                than its cache block size.</para>
                <para><emphasis role="bold">Note:</emphasis> If this is a unified cache, the 
                corresponding i- and d- sizes must be equal.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>
        
      </section>
      
      <section xml:id="dbdoclet.50569374_34579">
        <title>Memory Management Unit properties</title>
        
        <para>To aid a client in &#8220;taking over&#8221; the translation
        mechanism and still interact with OF (via the client interface), the
        client needs to know what translations have been established by OF. The
        following standard property shall exist within the package to which the
        &#8220;mmu&#8221; property of the /chosen package refers.</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;translations&#8221;</literal></emphasis></term>
              <listitem>
                <para>This property, consisting of sets of translations, defines the
                currently active translations that have been established by OF (e.g.,
                using map). Each set has the following format:</para>
                <programlisting><![CDATA[(virt size phys mode)]]></programlisting>                
                <para>Each value is encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>

        
      </section>
      
      <section>
        <title>SLB properties</title>
        
        <para>Since the PA defines the MMU as being part of the processor, the
        properties defined by Section 3.6.5 of 
        <xref linkend="dbdoclet.50569387_45524" />and the following MMU-related
        properties as appropriate to the specific processor implementation shall
        be presented under &#8220;cpu&#8221; nodes.</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;slb-size&#8221;</literal></emphasis></term>
              <listitem>
                <para>Standard <emphasis>property name</emphasis>, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, that 
                represents the total number of SLB entries.</para>
                <para><emphasis role="bold">Note:</emphasis>
                <xref linkend="dbdoclet.50569387_99718" />requires that the SLB be
                fully-associative, and appear to be a unified organization. Therefore,
                properties to report SLB sets, split, and sizes and sets of i and d SLBs
                are not defined.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>
        
      </section>

    </section>
    
    <section>
      <title>Ancillary (L2,L3...) cache node properties</title>
      <para>Some systems might include secondary (L2) or tertiary (L3), etc.
      cache(s). As with the L1 caches, they can be implemented as either
      Harvard-style or unified. Unlike the L1 properties, that are contained
      within the 
      <emphasis role="bold"><literal>&#8220;cpu&#8221;</literal></emphasis> nodes, the properties of ancillary
      caches are contained within other device tree nodes.</para>
      <para>The following properties define the characteristics of such
      ancillary caches. These properties shall be contained within a child node
      of one of the CPU nodes or, for platforms that support dynamic
      reconfiguration of cpus, the CPUS node; this is to allow path-name access
      to the node. These properties shall always be contained within a child
      node of the CPUS node. All 
      <emphasis role="bold"><literal>&#8220;cpu&#8221;</literal></emphasis> nodes that share the same ancillary
      cache (including the cpu node under which the ancillary cache node is
      contained) shall contain an 
      <emphasis role="bold"><literal>&#8220;l2-cache&#8221;</literal></emphasis> property whose value is the 
      <emphasis>phandle</emphasis> of that ancillary cache node.</para>
      <para>
      <emphasis role="bold">Note:</emphasis> The 
      <emphasis role="bold"><literal>&#8220;l2-cache&#8221;</literal></emphasis> property shall be used in one
      level of the cache hierarchy to represent the next level. The device node
      for a subsequent level shall appear as a child of one of the caches in
      the hierarchy to allow path-name traversal. The preceding sentence does
      not apply to platforms that support dynamic reconfiguration of cpus or
      platforms designed after 07/2005.</para>

      <variablelist>
        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;device_type&#8221;</literal></emphasis></term>
            <listitem>
              <para>Standard <emphasis>property name</emphasis>; the device_type of ancillary cache
              nodes shall be 
              <emphasis role="bold"><literal>&#8220;cache&#8221;</literal></emphasis>.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;cache-unified&#8221;</literal></emphasis></term>
            <listitem>
              <para>This property, if present, indicates that the cache at this node
              has a physically unified organization. Absence of this property indicates
              that the caches at this node are implemented as separate instruction and
              data caches. Unless otherwise noted, separate instruction and data caches
              require the architected instruction sequence for instruction modification
              so that data cache stores appear in the instruction cache.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;i-cache-size&#8221;</literal></emphasis></term>
            <listitem>
              <para>Standard <emphasis>property name</emphasis>, encoded as with 
              <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents the total size (in
              bytes) of the instruction cache at this node.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;i-cache-sets&#8221;</literal></emphasis></term>
            <listitem>
              <para>Standard <emphasis>property name</emphasis>, encoded as with 
              <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents number of associativity
              sets of the instruction cache at this node. A value of 1 signifies that
              the instruction cache is fully associative.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;d-cache-size&#8221;</literal></emphasis></term>
            <listitem>
              <para>Standard <emphasis>property name</emphasis>, encoded as with 
              <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents the total size (in
              bytes) of the data cache at this node.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;d-cache-sets&#8221;</literal></emphasis></term>
            <listitem>
              <para>Standard <emphasis>property name</emphasis>, encoded as with 
              <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents number of associativity
              sets of the instruction cache at this node. A value of 1 signifies that
              the instruction cache is fully associative.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;l2-cache&#8221;</literal></emphasis></term>
            <listitem>
              <para>Standard <emphasis>property name</emphasis>, encoded as with 
              <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents the next level of cache
              in the memory hierarchy.</para>
              <para>Absence of this property indicates that no further levels of cache
              are present. If present, its value is the 
              <emphasis>phandle</emphasis> of the device node that represents the cache
              at the next level.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;i-cache-line-size&#8221;</literal></emphasis></term>
            <listitem>
              <para>Standard <emphasis>property name</emphasis>, encoded as with 
              <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents the internal instruction
              cache's line size, in bytes, if different than its block size.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>&#8220;d-cache-line-size&#8221;</literal></emphasis></term>
            <listitem>
              <para>Standard <emphasis>property name</emphasis>, encoded as with 
              <emphasis role="bold"><literal>encode-int</literal></emphasis>, that represents the internal data
              cache's line size, in bytes, if different than its block size.</para>
              <para>
              <emphasis role="bold">Note:</emphasis> If this is a unified cache, the corresponding
              i- and d- sizes must be equal.</para>
            </listitem>
			  </varlistentry>
      </variablelist>
      
    </section>
    
  </section>
  
  <section xml:id="dbdoclet.50569374_77797">
    <title>Methods</title>
    
    <para>This section describes the additional standard methods required of a
    PA OF implementation.</para>
    
    <section>
      <title>MMU related methods</title>
      
      <para>The MMU methods defined by section 3.6.5. of 
      <xref linkend="dbdoclet.50569387_45524" />shall be implemented by CPU
      nodes. The value of the 
      <emphasis role="bold"><literal>mode</literal></emphasis> parameter for the relevant methods (e.g., 
      <emphasis role="bold"><literal>map</literal></emphasis>) shall be the value that is contained within
      PTEs that control Write-through, Cache-Inhibit, Memory-coherent, Guarded
      and the 2 protection bits; thus, its format is: 
      <emphasis role="bold"><literal>WIMGxPP</literal></emphasis>, where x is a reserved bit that shall be 0.
      In order for I/O accesses to be properly performed in a LoPAR system,
      address ranges that are mapped by 
      <emphasis role="bold"><literal>map-in</literal></emphasis> shall be marked as Cache-Inhibited,
      Guarded.</para>
      <para>The default mode (i.e., the mode specified when the value of the 
      <emphasis role="bold"><literal>mode</literal></emphasis> argument is -1) for the 
      <emphasis role="bold"><literal>map-in</literal></emphasis> and 
      <emphasis>modify</emphasis> MMU methods of CPU nodes is defined as
      follows:</para>
      <para>If the beginning of the physical address range affected by the
      operation refers to system memory, the values for 
      <emphasis role="bold"><literal>WIMGxPP</literal></emphasis> shall be W=0, I=0, M=0, G=1, PP=10.</para>
      <para>If the beginning of the physical address range affected by the
      operation refers to an I/O address, the values for WIMGxPP shall be W=1,
      I=1, M=0, G=1, PP=10.</para>
      
    </section>
    
  </section>
  
  <section>
    <title>Client Interface Requirements</title>
    
    <para>A PA OF implementation shall implement a client interface (as defined
    in chapter 6 of 
    <xref linkend="dbdoclet.50569387_45524" />) according to the specifications
    contained within this section.</para>
    
    <section>
      <title>Calling Conventions</title>
      <para>To invoke a client interface service, a 
      <emphasis>client program</emphasis> constructs a client interface 
      <emphasis>argument array</emphasis> as specified in the core OF document,
      places its address in 
      <emphasis role="bold"><literal>r3</literal></emphasis> and transfers to the 
      <emphasis>client interface handler</emphasis>, with the return address in
      <emphasis role="bold"><literal>lr</literal></emphasis>. (A typical way of accomplishing this is to copy
      the 
      <emphasis>client interface handler</emphasis>'s address into 
      <emphasis role="bold"><literal>ctr</literal></emphasis> and executing a 
      <emphasis role="bold"><literal>bctrl</literal></emphasis>.)</para>
      <para>The term &#8220;preserved&#8221; below shall mean that the register
      has the same value when returning as it did when the call was
      made.</para>

      <table frame="all" pgwide="1">
        <title>Register usage conventions</title>
        <tgroup cols="6">
          <colspec colname="c1" colwidth="16*" align="center" />
          <colspec colname="c2" colwidth="16*" />
          <colspec colname="c3" colwidth="16*" />
          <colspec colname="c4" colwidth="16*" />
          <colspec colname="c5" colwidth="16*" />
          <colspec colname="c6" colwidth="16*" align="center" />
          <thead>
            <row>
              <entry>
                <para>
                  <emphasis role="bold">Register(s)</emphasis>
                </para>
              </entry>
              <entry nameend="c3" namest="c2" align="center">
                <para>
                  <emphasis role="bold">Value -- real-mode</emphasis>
                </para>
              </entry>
              <entry nameend="c5" namest="c4" align="center">
                <para>
                  <emphasis role="bold">Value -- virt-mode</emphasis>
                </para>
              </entry>
              <entry>
                <para>
                  <emphasis role="bold">Notes</emphasis>
                </para>
              </entry>
            </row>
          </thead>
          <tbody>
            <row>
              <entry>
                <para>&#160;</para>
              </entry>
              <entry>
                <para>If either the FWNMI, or LPAR option is implemented</para>
              </entry>
              <entry>
                <para>If neither the FWNMI or LPAR option is implemented</para>
              </entry>
              <entry>
                <para>If either the FWNMI, or LPAR option is implemented</para>
              </entry>
              <entry>
                <para>If neither the FWNMI or LPAR option is implemented</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>msr</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>client interface shall not modify</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>cr</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>1</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>r1-r2</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>r3</para>
              </entry>
              <entry>
                <para>argument array address on client interface entry</para>
              </entry>
              <entry>
                <para>argument array address on client interface entry</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>2</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>&#160;</para>
              </entry>
              <entry>
                <para>result value (true or false) on client interface
                return</para>
              </entry>
              <entry>
                <para>result value (true or false) on client interface
                return</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>2</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>r13-r31</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>sprg0, sprg1, and sprg3</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall not modify</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>fpscr</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>f0-f31</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>lr,</para>
                <para>ctr,</para>
                <para>xer</para>
              </entry>
              <entry>
                <para>undefined</para>
              </entry>
              <entry>
                <para>undefined</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>sr0-sr15</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>client interface shall not modify</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>vr0-vr31</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real mode</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>dec</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall not modify</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real mode</para>
              </entry>
              <entry>
                <para>&#160;</para>
              </entry>
            </row>
            <row>
              <entry>
                <para>Other SPRs</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>client interface shall preserve</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>same as real-mode</para>
              </entry>
              <entry>
                <para>3</para>
              </entry>
            </row>
          </tbody>
        </tgroup>
      </table>
      <para><emphasis role="bold">Notes:</emphasis></para>
      
      <orderedlist>		      
        <listitem>
          <para>Only the non-volatile fields (
          <emphasis>cr2-cr4</emphasis>) need to be preserved.</para>
        </listitem>

        <listitem>
          <para>As defined by section 6.3.1. of 
          <xref linkend="dbdoclet.50569387_45524" />.</para>
        </listitem>

        <listitem>
          <para>Other special purpose registers</para>
        </listitem>
      </orderedlist>		      
          
      <para>The 
      <emphasis>client interface handler</emphasis> shall perform the service
      specified by the contents of the argument array that begins at the
      address in 
      <emphasis role="bold"><literal>r3</literal></emphasis>, place the return value (indicating success or
      failure of the attempt to invoke the client interface service) back into 
      <emphasis role="bold"><literal>r3</literal></emphasis>, and return to the 
      <emphasis>client program</emphasis>. This is typically done by a Branch
      to Link Register (
      <emphasis role="bold"><literal>blr</literal></emphasis>).</para>
      <para>The 
      <emphasis>client interface handler</emphasis> shall preserve the contents
      of the Stack Pointer (r1), TOC Pointer (r2), Condition Register (
      <emphasis role="bold"><literal>cr</literal></emphasis>) all non-volatile registers (r13-r31) and all
      special purpose registers except lr, ctr and xer.</para>
      <para>The preservation of r2 allows TOC-based client programs to function
      correctly. OF shall
      <emphasis>not</emphasis> depend upon whether its client is TOC-based or
      not. If the client interface handler, itself, is TOC-based, it must
      provide for the appropriate initialization of its 
      <emphasis role="bold"><literal>r2</literal></emphasis>.</para>
      
    </section>
    
  </section>
  
  <section>
    <title>Client Program Requirements</title>
    
    <section>
      <title>Load Address</title>
      
      <para>The client&#8217;s load address is specified by the value of the 
      <emphasis role="bold"><literal>load-base</literal></emphasis> Configuration Variable. The value of 
      <emphasis role="bold"><literal>load-base</literal></emphasis> defines the default load address for 
      <emphasis>client programs</emphasis> when using the 
      <emphasis role="bold"><literal>load</literal></emphasis> method. 
      <emphasis role="bold"><literal>Load-base</literal></emphasis> shall be a real address in real mode or a
      virtual address in virtual mode. Note that this address represents the
      area into which the client program file will be read by 
      <emphasis role="bold"><literal>load</literal></emphasis>; it does not correspond to the addresses at
      which the program will be executed. All of physical memory from 
      <emphasis role="bold"><literal>load-base</literal></emphasis> to either the start of OF physical memory
      or the end of physical memory, whichever comes first, shall be available
      for loading the client program.</para>
      
    </section>
    
    <section>
      <title>Initial Program State</title>
      <para>This section defines the &#8220;initial program state&#8221;, the
      execution environment that exists when the first machine instruction of a
      
      <emphasis>client program</emphasis> of the format specified above begins
      execution. Many aspects of the &#8220;initial program state&#8221; are
      established by 
      <emphasis role="bold"><literal>init-program</literal></emphasis>, which sets the 
      <emphasis>saved program state</emphasis> so that subsequent execution of 
      <emphasis role="bold"><literal>go</literal></emphasis> will begin execution of the 
      <emphasis>client program</emphasis> with the specified environment.</para>
      
      <section>
        <title>Initial Register Values</title>
        <para>Upon entry to the client program, the following registers shall
        contain the following values:</para>
  
        <table frame="all" pgwide="1" xml:id="dbdoclet.50569374_45461">
          <title>Initial Register Values</title>
          <?dbhtml table-width="80%" ?>
          <?dbfo table-width="80%" ?>
          <tgroup cols="3">
            <colspec colname="c1" colwidth="30*" align="center" />
            <colspec colname="c2" colwidth="60*" />
            <colspec colname="c3" colwidth="10*" align="center" />
            <thead>
              <row>
                <entry>
                  <para>
                    <emphasis role="bold">Register(s)</emphasis>
                  </para>
                </entry>
                <entry align="center">
                  <para>
                    <emphasis role="bold">Value</emphasis>
                  </para>
                </entry>
                <entry>
                  <para>
                    <emphasis role="bold">Notes</emphasis>
                  </para>
                </entry>
              </row>
            </thead>
            <tbody>
              <row>
                <entry>
                  <para>msr</para>
                </entry>
                <entry>
                  <para>EE = 0, interrupts disabled</para>
                </entry>
                <entry>
                  <para>1</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>&#160;</para>
                </entry>
                <entry>
                  <para>PR = 0, supervisor state</para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>&#160;</para>
                </entry>
                <entry>
                  <para>FP = 1, floating point enabled</para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>&#160;</para>
                </entry>
                <entry>
                  <para>ME = 1, machine checks enabled</para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>&#160;</para>
                </entry>
                <entry>
                  <para>FE0, FE1 = 0, floating point exceptions disabled</para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>&#160;</para>
                </entry>
                <entry>
                  <para>IP, see 
                  <xref linkend="dbdoclet.50569374_27751" /></para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>&#160;</para>
                </entry>
                <entry>
                  <para>IR,DR, see 
                  <xref linkend="dbdoclet.50569374_25139" /></para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>&#160;</para>
                </entry>
                <entry>
                  <para>SF=0, 32-bit mode</para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>&#160;</para>
                </entry>
                <entry>
                  <para>ILE,LE, little endian support</para>
                </entry>
                <entry>
                  <para>2</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>r1</para>
                </entry>
                <entry>
                  <para>See 
                  <xref linkend="dbdoclet.50569374_27292" /></para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>r2</para>
                </entry>
                <entry>
                  <para>0</para>
                </entry>
                <entry>
                  <para>3</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>r3</para>
                </entry>
                <entry>
                  <para>reserved for platform binding</para>
                </entry>
                <entry>
                  <para>4</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>r4</para>
                </entry>
                <entry>
                  <para>reserved for platform binding</para>
                </entry>
                <entry>
                  <para>4</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>r5</para>
                </entry>
                <entry>
                  <para>See 
                  <xref linkend="dbdoclet.50569374_31886" /></para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>r6, r7</para>
                </entry>
                <entry>
                  <para>See 
                  <xref linkend="dbdoclet.50569374_13831" /></para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
              <row>
                <entry>
                  <para>Other user mode registers</para>
                </entry>
                <entry>
                  <para>0</para>
                </entry>
                <entry>
                  <para>&#160;</para>
                </entry>
              </row>
            </tbody>
          </tgroup>
        </table>
        <para>
          <emphasis role="bold">Notes:</emphasis>
        </para>
  
        <orderedlist>		      
          <listitem>
            <para>OF will typically require the use of external interrupts for its
            
            <emphasis>user interface</emphasis>. However, when a 
            <emphasis>client program</emphasis> is invoked, external interrupts shall
            be disabled. If a 
            <emphasis>client program</emphasis> causes the invocation of the user
            interface, external interrupts 
            <emphasis>may</emphasis> be re-enabled.</para>
          </listitem>
  
          <listitem>
            <para>The 601 processor uses a different mechanism for controlling the
            endian-mode of the processor. On the 601, the LE bit is contained in the
            HID0 register; this bit controls the endian-mode of both program and
            privileged states.</para>
          </listitem>
  
          <listitem>
            <para>OF does not make any assumptions about whether a client program
            is TOC-based or not. It is the responsibility of the client program to
            set 
            <emphasis>r2</emphasis> to its TOC, if necessary.</para>
          </listitem>
  
          <listitem>
            <para>As defined in the relevant section of the platform
            binding.</para>
          </listitem>
        </orderedlist>		      
  
      </section>
      
      <section xml:id="dbdoclet.50569374_27292">
        <title>Initial Stack</title>
        
        <para>Client programs shall be invoked with a valid stack pointer (
        <emphasis>r1</emphasis>) with at least 32 KB of memory available for
        stack growth. The stack pointer shall be 16-byte aligned, reserving
        sufficient room for a linkage area (32 bytes above the address in r1). If
        the system is executing in Real-Mode, the value in r1 is a real address;
        if in Virtual-Mode, the address in r1 is a mapped virtual address.</para>
        
      </section>
      
      <section xml:id="dbdoclet.50569374_31886">
        <title>Client Interface Handler Address</title>
        
        <para>When client programs are invoked, 
        <emphasis>r5</emphasis> shall contain the address of the entry point of
        the 
        <emphasis>client interface handler</emphasis>. If the system is executing
        in Real-Mode, the value in r5 is a real address; if in Virtual-Mode, the
        address in r5 is a mapped virtual address.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> This address points to the first instruction of
        the 
        <emphasis>client interface handler</emphasis>, not to a procedure
        descriptor.</para>
        
      </section>
      
      <section xml:id="dbdoclet.50569374_13831">
        <title>Client Program Arguments</title>
        
        <para>The calling program 
        <emphasis>may</emphasis> pass to the client an array of bytes of arbitrary
        content; if this array is present, its address and length shall be passed
        in registers 
        <emphasis>r6</emphasis> and 
        <emphasis>r7</emphasis>, respectively. For programs booted directly by
        OF, the length of this array is zero. Secondary boot programs may use
        this argument array to pass information to the programs that they
        boot.</para>
        <para>
        <emphasis role="bold">Note:</emphasis> The OF standard makes no provision for
        specifying such an array or its contents. Therefore, in the absence of
        implementation-dependent extensions, a client program executed directly
        from an OF implementation will not be passed such an array. However,
        intermediate boot programs that simulate or propagate the OF client
        interface to the programs that they load can provide such an array for
        their clients.</para>
        <para>
        <emphasis role="bold">Note:</emphasis>
        <emphasis>boot</emphasis> command line arguments, typically consisting of
        the name of a file to be loaded by a secondary boot program followed by
        flags selecting various secondary boot and OS options, are provided to
        client programs via the 
        <emphasis role="bold"><literal>&#8220;bootargs&#8221;</literal></emphasis> and 
        <emphasis role="bold"><literal>&#8220;bootpath&#8221;</literal></emphasis> properties of the 
        <emphasis role="bold"><literal>/chosen</literal></emphasis> node.</para>
        
      </section>

    </section>
    
    <section>
      <title>Caching</title>
      
      <para>The caches of the processor shall be enabled when the client
      program is called. The I-cache shall be consistent with the D-cache for
      all memory areas occupied by the client program. Memory areas allocated
      on behalf of the client program shall be marked as cacheable. Accesses to
      &#8220;I/O&#8221; devices (especially, to devices across
      &#8220;bridges&#8221;) shall be made with the register access words
      (e.g., 
      <emphasis role="bold"><literal>%rl@</literal></emphasis>). All processors in a SMP system shall have the
      same consistent view of all memory areas (for data references). No more
      than one processor shall have a modified copy of the same data area in
      its cache when the client program is called.</para>
      <para>
      <emphasis role="bold">Note:</emphasis> If firmware makes cacheable M=0 data references
      from different processors on a SMP system, it may have to perform
      additional cache management to meet this requirement.</para>
      
    </section>
    
    <section xml:id="dbdoclet.50569374_27751">
      <title>Interrupts</title>
      
      <para>OF requires that interrupts be &#8220;vectored&#8221; to its
      handlers when it is in control of the processor; this will occur when the
      User Interface is running. Client Interface calls are considered to
      execute in the environment of the client, and hence, OF does not assume
      ownership of interrupts.</para>
      <para>
      <emphasis role="bold">Note:</emphasis> There used to be a paragraph here that said an
      area of memory was to be reserved by the client program for the exclusive
      use of OF. This requirement has been removed, since the sharing of
      interrupt vectors on these platforms has not been found to be
      practical.</para>
      <para>OF shall save and restore the first location of each interrupt that
      it wants to &#8220;take over&#8221;. I.e., whenever OF needs the use of
      an interrupt, it shall save the current contents of the corresponding
      entry point and replace that location with a branch to its entry point.
      When OF returns control, it shall restore the RAM location to its
      original contents.</para>
      
    </section>
    
    <section>
      <title>Client callbacks</title>
      
      <para>This section defines the callback mechanism that allows OF to
      access services exported to it by the client program. As described in
      section 6.3.2 and the glossary entries for 
      <emphasis role="bold"><literal>callback</literal></emphasis> and 
      <emphasis role="bold"><literal>$callback</literal></emphasis> in 
      <xref linkend="dbdoclet.50569387_45524" />, the callback mechanism
      follows the same rules as those of Client interface calls. I.e., an 
      <emphasis>argument array</emphasis> is constructed by OF and the address
      of that array is passed (via 
      <emphasis role="bold"><literal>r3</literal></emphasis>) to the client&#8217;s callback routine; the
      address of the callback routine is supplied to OF by means of the 
      <emphasis role="bold"><literal>set-callback</literal></emphasis> client call.</para>
      <para>If the system is running in Real-Mode, the address of the client
      callback routine shall be a real address; if it is running in
      Virtual-Mode, the client callback routine address shall be a mapped
      virtual address.</para>
      
      <section xml:id="dbdoclet.50569374_11616">
        <title>Real-Mode physical memory management assist
        callback</title>
        
        <para>Once the control of physical memory is transferred to the client
        program, OF which is running in real-mode shall use the callback service
        provided by the client program to allocate physical memory. Client
        programs which expect OF to operate in read-mode must implement the
        following physical memory management client callback routines for
        OF:</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>alloc-real-mem</literal></emphasis></term>
              <listitem>
                <para>IN: [address] min_addr, [address] max_addr, size, mode</para>
                <para>OUT: error, [address] real_addr</para>
                <para>This routine allocates a contiguous physical memory of 
                <emphasis>size</emphasis> bytes within the address range between 
                <emphasis>min_addr</emphasis> and
                <emphasis>max_addr</emphasis>. The 
                <emphasis role="bold"><literal>mode</literal></emphasis> parameter contains the WIMGxPP bits as defined
                in 
                <xref linkend="dbdoclet.50569374_77797" />A non-zero error code shall be
                returned if the mapping cannot be performed. If error code is zero (i.e.
                allocation is succeeded) the routine returns the base address of the
                physical memory allocated for OF.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>
        
      </section>
      
      <section>
        <title>Virtual address translation assist callbacks</title>
        
        <para>As mentioned in 
        <xref linkend="dbdoclet.50569374_96317" />, when OF is in Virtual-Mode,
        client programs that take over control of the system&#8217;s memory
        management must provide a set of callbacks that implement MMU functions.
        This section defines the input arguments and return values for these
        callbacks. The notation follows the style used in chapter 6 of the OF
        specification 
        <xref linkend="dbdoclet.50569387_45524" />.</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>map</literal></emphasis></term>
              <listitem>
                <para>IN: [address] phys, [address] virt, size, mode</para>
                <para>OUT: throw-code, error</para>
                <para>This routine creates system-specific translation information; this
                will typically include the addition of PTEs to the HTAB. If the mapping
                is successfully performed, a value of zero shall be placed in the 
                <emphasis>error</emphasis> cell of the argument array; a non-zero error
                code shall be returned in 
                <emphasis>error</emphasis> if the mapping cannot be performed.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>unmap</literal></emphasis></term>
              <listitem>
                <para>IN: [address] virt, size</para>
                <para>OUT: throw-code</para>
                <para>The system removes any data structures (e.g., PTEs) for the virtual
                address range.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold">translate</emphasis></term>
              <listitem>
                <para>IN: [address] virt</para>
                <para>OUT: throw-code, error, [address] real, mode</para>
                <para>The system attempts to compute the real address (
                <emphasis>real</emphasis>) to which the virtual address (
                <emphasis>virt</emphasis>) is mapped. If the translation is successful, a
                PTE shall be placed into the HTAB for this translation, the number of
                return cells shall be four with the resulting real address returned in 
                <emphasis>real</emphasis> and 
                <emphasis>error</emphasis> shall be set to 
                <emphasis role="bold"><literal>false</literal></emphasis> (0). If the translation is not successful, the
                number of return cells shall be two and 
                <emphasis>error</emphasis> shall be set to a non-zero error code.</para>
                <para>This call shall be made when OF handles a DSI/ISI within the User
                interface. A successful result of the translate call indicates that OF
                can complete the interrupted access; a failure indicates that an access
                was made to an invalid address.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>
        
      </section>

    </section>
    
  </section>
  
  <section>
    <title>User Interface Requirements</title>
    
    <para>An implementation of OF for the PA shall conform to the core
    requirements as specified in 
    <xref linkend="dbdoclet.50569387_45524" />and the following PA-specific
    extensions.</para>
    
    <section>
      <title>Machine Register Access</title>
      
      <para>The following 
      <emphasis>user interface</emphasis> commands represent PA registers within
      the 
      <emphasis>saved program state</emphasis>. Executing the command returns
      the saved value of the corresponding register. The saved value may be set
      by preceding the command with 
      <emphasis>to</emphasis>; the actual registers are restored to the saved
      values when 
      <emphasis role="bold"><literal>go</literal></emphasis> is executed.</para>
      <para>The following command displays the PA processor's 
      <emphasis>saved program state</emphasis>.</para>
      <para>
        <emphasis role="bold"><literal>.registers</literal></emphasis>
      </para>
      
      <section>
        <title>Branch Unit Registers</title>
        
        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>%cr</literal></emphasis></term>
              <listitem>
                <para>Access saved copy of Condition Register.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>%ctr</literal></emphasis></term>
              <listitem>
                <para>Access saved copy of Count Register.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>%lr</literal></emphasis></term>
              <listitem>
                <para>Access saved copy of Link Register.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>%msr</literal></emphasis></term>
              <listitem>
                <para>Access saved copy of the low order 16 bits of SRR1 register.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>%srr0</literal></emphasis> and 
                  <emphasis role="bold"><literal>%srr1</literal></emphasis></term>
              <listitem>
                <para>Access saved copy of Save/Restore Registers.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>%pc</literal></emphasis></term>
              <listitem>
                <para>An alias of &#8220;
                <emphasis role="bold"><literal>%srr0</literal></emphasis> &#8221;</para>
              </listitem>
  			  </varlistentry>
        </variablelist>
        
      </section>
      
      <section>
        <title>Fixed-Point Registers</title>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>%r0</literal></emphasis> through 
                  <emphasis role="bold"><literal>%r31</literal></emphasis></term>
              <listitem>
                <para>Access saved copies of fixed-point registers.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>%xer</literal></emphasis></term>
              <listitem>
                <para>Access saved copy of XER register.</para>
              </listitem>
  			  </varlistentry>

          <varlistentry>
            <term><emphasis role="bold"><literal>%sprg0</literal></emphasis> through 
                  <emphasis role="bold"><literal>%sprg3</literal></emphasis></term>
              <listitem>
                <para>Access saved copies of SPRG registers.</para>
              </listitem>
    		  </varlistentry>
        </variablelist>
        
      </section>
      
      <section>
        <title>Floating-Point Registers</title>
        
        <para>Unlike the other registers, the floating point unit registers are
        not normally saved, since they are not used by OF. The following access
        words, therefore, access the registers directly.</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>%f0</literal></emphasis> through 
                  <emphasis role="bold"><literal>%f31</literal></emphasis></term>
              <listitem>
                <para>Access floating point registers.</para>
              </listitem>
  			  </varlistentry>
  
          <varlistentry>
            <term><emphasis role="bold"><literal>%fpscr</literal></emphasis></term>
              <listitem>
                <para>Access Floating Point Status and Control Register.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>

      </section>

    </section>
    
  </section>
  
  <section xml:id="dbdoclet.50569374_72253">
    <title>Configuration Variables</title>
    
    <para>In addition to the standard Configuration Variables defined by the
    core OF document 
    <xref linkend="dbdoclet.50569387_45524" />, the following Configuration
    Variables shall be implemented for the PA:</para>

    <variablelist>
      <varlistentry>
        <term><emphasis role="bold"><literal>&#8220;little-endian?&#8221;</literal></emphasis></term>
          <listitem>
            <para>This boolean variable controls the endian-mode of OF. If 
            <emphasis role="bold"><literal>true</literal></emphasis> (-1), the endian-mode is Little-Endian; if 
            <emphasis role="bold"><literal>false</literal></emphasis> (0), the endian-mode is Big-Endian. The default
            value is implementation dependent.</para>
          </listitem>
		  </varlistentry>

      <varlistentry>
        <term><emphasis role="bold"><literal>&#8220;real-mode?&#8221;</literal></emphasis></term>
          <listitem>
            <para>This boolean variable controls the address translation mode of OF. If    
            <emphasis role="bold"><literal>true</literal></emphasis> (-1), the addressing mode is Real-Mode; if 
            <emphasis role="bold"><literal>false</literal></emphasis> (0), the addressing mode is Virtual-Mode. The
            default value is implementation dependent.</para>
          </listitem>
		  </varlistentry>

      <varlistentry>
        <term><emphasis role="bold"><literal>&#8220;real-base&#8221;</literal></emphasis></term>
          <listitem>
            <para>This integer variable defines the starting physical address to be
            used by OF.</para>
          </listitem>
		  </varlistentry>

      <varlistentry>
        <term><emphasis role="bold"><literal>&#8220;real-size&#8221;</literal></emphasis></term>
          <listitem>
            <para>This integer variable defines the size of the physical address space
            which can be used by OF.</para>
          </listitem>
		  </varlistentry>

      <varlistentry>
        <term><emphasis role="bold"><literal>&#8220;virt-base&#8221;</literal></emphasis></term>
          <listitem>
            <para>This integer variable defines the starting virtual memory address
            which can be used by OF.</para>
          </listitem>
		  </varlistentry>

      <varlistentry>
        <term><emphasis role="bold"><literal>&#8220;virt-size&#8221;</literal></emphasis></term>
          <listitem>
            <para>This integer variable defines the size of the virtual address space
            which can be used by OF.</para>
          </listitem>
		  </varlistentry>

      <varlistentry>
        <term><emphasis role="bold"><literal>&#8220;load-base&#8221;</literal></emphasis></term>
          <listitem>
            <para>This integer variable defines the default load address for 
            <emphasis>client programs</emphasis> when using the 
            <emphasis role="bold"><literal>load</literal></emphasis> method. The default value is implementation
            dependent.</para>
          </listitem>
		  </varlistentry>
    </variablelist>

  </section>
  
  <section>
    <title>MP Extensions</title>
    
    <para>This section specifies the application of OF to PA multiprocessor
    (MP) systems. An OF implementation for an MP PA system shall implement the
    extensions described in this section as well as the requirements described
    in previous sections of this binding.</para>
    
    <section>
      <title>The Device Tree</title>
      
      <para>This section defines an additional property under the
      <emphasis role="bold"><literal>/chosen</literal></emphasis> node for a MP extension. Refer to 
      <xref linkend="dbdoclet.50569374_37877" />for more details about the
      device tree structure for a MP Configuration.</para>
      
      <section>
        <title>Additional Properties</title>
        <para>
        <emphasis role="bold"><literal>/chosen</literal></emphasis> Node Properties</para>

        <variablelist>
          <varlistentry>
            <term><emphasis role="bold"><literal>&#8220;cpu&#8221;</literal></emphasis></term>
              <listitem>
                <para><emphasis>property name</emphasis>, identifies the running CPU.</para>
                <para><emphasis>prop-encode-array</emphasis>: An integer, encoded as with 
                <emphasis role="bold"><literal>encode-int</literal></emphasis>, which contains the i-handle of the CPU
                node that is associated with the &#8220;running&#8221; CPU.</para>
              </listitem>
  			  </varlistentry>
        </variablelist>

        
      </section>
    
    </section>
    
    <section>
      <title>Initialization</title>
      
      <para>OF shall select one processor, using an algorithm of its choice, to
      be the &#8220;master&#8221; processor, which performs the role of the
      single processor on a uniprocessor system, either booting the client or
      providing the user interface. OF shall place all the remaining processors
      into stopped state, a state in which the processor does not perform OF or
      client functions and does not interfere with the operation of the master
      processor. A processor in stopped state remains in that state unless and
      until an executing client starts it using the 
      <emphasis role="bold"><literal>start-cpu</literal></emphasis> client service defined below.</para>
      <para>Client programs shall use the OF 
      <emphasis role="bold"><literal>start-cpu</literal></emphasis> client interface service to start all
      processors before it reclaims the OF memory</para>
      <para>On machines in which a machine check on one processor is broadcast
      to all processors, the processors which are either in the idle or stopped
      state shall not change their states due to a machine check on another
      processor: OF shall not depend on the contents of the low vector (IP=0)
      in the event of a machine check.</para>
      <para>
      <xref linkend="dbdoclet.50569374_85573" />depicts the relationship of the
      Running, Stopped and Idle States to each other. The 
      <emphasis>Client Interface Service</emphasis> calls are shown as how to
      move between the states.</para>

      <figure pgwide="1" xml:id="dbdoclet.50569374_85573">
        <title>Stopped, Running, and Idle State Diagram</title>
        <mediaobject>
          <imageobject role="html">
            <imagedata fileref="figures/PAPR-64.gif" format="GIF"
            scalefit="1" />
          </imageobject>
          <imageobject role="fo">
            <imagedata contentdepth="100%" fileref="figures/PAPR-64.gif"
            format="GIF" scalefit="1" width="100%" />
          </imageobject>
        </mediaobject>
      </figure>
      
      <para><emphasis role="bold">Note:</emphasis> OF's memory cannot be reclaimed by a client if
      a CPU is in the &#8220;stopped&#8221; or &#8220;idle&#8221; state.</para>
      
    </section>
    
    <section>
      <title>Client Interface Services</title>
      
      <para>The following client interface services are added for MP support on
      PA systems. These interfaces make the client program responsible for any
      Inter-CPU communication needed for these interfaces. The rationale for
      this is to architecturally separate the Inter-CPU communication mechanism
      of the firmware from the client program and vice versa.</para>

      <variablelist>
        <varlistentry>
          <term><emphasis role="bold"><literal>start-cpu</literal></emphasis></term>
            <listitem>
              <para>IN: nodeid, pc, arg</para>
              <para>OUT: none</para>
              <para>This client interface service starts the CPU. The 
              <emphasis>nodeid</emphasis> is the phandle of a node whose device_type is
              &#8220;cpu&#8221;.</para>
              <para><emphasis role="bold"><literal>Start-cpu</literal></emphasis> arranges for the CPU identified by phandle
              in <emphasis>nodeid</emphasis> to begin executing client code at the real
              address given by the 
              <emphasis>pc</emphasis> input with an argument, 
              <emphasis>arg,</emphasis> passed in register r3. When it begins execution,
              the started processor shall be in the endian mode of the client program,
              and in real (not translated) addressing mode. The contents of registers
              other than r3 are indeterminate.</para>
              <para>A client should not call 
              <emphasis role="bold"><literal>start-cpu</literal></emphasis> for the processor on which it is running,
              effectively restarting with a new pc and abandoning the only client
              thread. A jump or branch instruction shall be used instead to achieve the
              objective.</para>
              <para><emphasis role="bold"><literal>start-cpu</literal></emphasis> permits more than one processor to run at
              the same time, enabling multi-threaded client execution. In general, an
              OF client shall avoid multi-threaded operation within OF. Usually, this
              means that client threads running on different CPUs must use mutual
              exclusion to prevent more than one processor from making client service
              requests at any one time. The exceptions are that a client thread may
              invoke either the 
              <emphasis role="bold"><literal>stop-self</literal></emphasis> or 
              <emphasis role="bold"><literal>idle-self</literal></emphasis> client services defined below at any
              time.</para>
              <para><emphasis role="bold">Note:</emphasis> The results are undefined if the CPU identified
              by *phandle* has already been started (e.g. it is already running and has
              not exited) or *phandle* is not a valid package handle of a CPU device
              node.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>stop-self</literal></emphasis></term>
            <listitem>
              <para>IN: none</para>
              <para>OUT: none</para>
              <para>OF places the processor on which the caller was running into the
              &#8220;stopped&#8221; state. The client program is not-resumable.</para>
              <para><emphasis role="bold">Note:</emphasis> When an MP client program exits, one CPU
              invokes the 
              <emphasis role="bold"><literal>exit</literal></emphasis> client interface service, the others invoke the 
              <emphasis role="bold"><literal>stop-self</literal></emphasis> service.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>idle-self</literal></emphasis></term>
            <listitem>
              <para>IN: none</para>
              <para>OUT: none</para>
              <para>OF places the CPU on which this service was invoked into an 'idle'
              state, saving the *current state* of the client program, so that the
              client program may be resumed.</para>
              <para>A processor in idle state can be resumed using 
              <emphasis role="bold"><literal>resume-cpu</literal></emphasis> service defined below or restarted using 
              <emphasis role="bold"><literal>start-cpu</literal></emphasis>. If the processor is resumed, it executes
              a normal return to the client, as if its call to 
              <emphasis role="bold"><literal>idle-self</literal></emphasis> had just completed.</para>
              <para>
              <emphasis role="bold">Note:</emphasis> When a client program wants to enter the
              firmware user interface, one CPU invokes the 
              <emphasis>enter</emphasis> client interface service, the others invoke the     
              <emphasis role="bold"><literal>idle-self</literal></emphasis> service. The rational is that the user
              interface may affect the machine state in any way that it desires,
              therefore the client shall not depend on it.</para>
            </listitem>
			  </varlistentry>

        <varlistentry>
          <term><emphasis role="bold"><literal>resume-cpu</literal></emphasis></term>
            <listitem>
              <para>IN: nodeid</para>
              <para>OUT: none</para>
              <para>This client interface service is used to resume an *idled* CPU. The     
              <emphasis>nodeid</emphasis> is the phandle of a CPU node in idle
              state.</para>
              <para><emphasis role="bold"><literal>resume-cpu</literal></emphasis> arranges for that CPU to restore the
              CPU&#8217;s state as saved by 
              <emphasis role="bold"><literal>idle-self</literal></emphasis> and begin return to the client, completing
              the idle-self client service call that placed the CPU into idle state.
              The results are undefined if the CPU identified by *phandle* is not in an
              *idle* state by a previous call to the 
              <emphasis role="bold"><literal>idle-self</literal></emphasis> client interface service.</para>
              <para><emphasis role="bold">Note:</emphasis> When the client program is resumed via the GO
              (or similar) user interface command, the client program is resumed on the
              CPU which called the 
              <emphasis>enter</emphasis> service; the client program is responsible for
              calling the 
              <emphasis role="bold"><literal>resume-cpu</literal></emphasis> service to resume other idled CPU's, if
              that is the desired client program behavior.</para>
            </listitem>
			  </varlistentry>
      </variablelist>
      
    </section>
    
    <section>
      <title>Breakpoints</title>
      
      <para>If the breakpoint is taken by the firmware, without the client
      program's assistance, the other CPUs will continue to run in the client
      program. The client program may field the breakpoint 'trap' or 'vector'
      and idle the other CPUs before entering the PROM. The platform binding
      document has to specify how this is done to avoid loss of state at
      breakpoint time.</para>
      
    </section>
    
    <section>
      <title>Serialization</title>
      
      <para>The firmware is a single threaded program, from the client
      program's point of view. Only the 
      <emphasis role="bold"><literal>idle-self</literal></emphasis>, 
      <emphasis role="bold"><literal>stop-self</literal></emphasis>, 
      <emphasis>enter</emphasis> and 
      <emphasis role="bold"><literal>exit</literal></emphasis> client interfaces may be invoked simultaneously
      on different CPUs. Furthermore, only a single CPU may invoke the 
      <emphasis>enter</emphasis> or 
      <emphasis role="bold"><literal>exit</literal></emphasis> client interface at any one time. The other CPUs
      must use the 
      <emphasis role="bold"><literal>idle-self</literal></emphasis> or 
      <emphasis role="bold"><literal>stop-self</literal></emphasis> client interface service.</para>
      <para>
      <emphasis role="bold">Note:</emphasis> The results are undefined if the client program
      invokes client interface services including breakpoint traps (other than
      the 
      <emphasis role="bold"><literal>enter/exit stop-self/idle-self</literal></emphasis> case listed above)
      simultaneously on more than a single CPU.</para>
      <para>
      <emphasis role="bold">Note:</emphasis> Since locking mechanisms are subject to client
      program policy, the client program is responsible for implementing any
      necessary mechanism to insure that it adheres to this policy. Further,
      the client program should disable any preemption mechanism before calling
      a client interface service to avoid rescheduling a thread of execution in
      the firmware on a different CPU if such a mechanism exists in the client
      program.</para>
      
    </section>
    
  </section>
  
</chapter>