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tests: Add a test for the MMU radix page table walks

Browse Source 
This adds tests to check that the MMU and dTLB are translating
addresses and checking permissions correctly.

We use a simple 2-level radix tree.  The radix tree maps 2GB of
address space and has a 1024-entry page directory pointing to
512-entry page table pages.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
pull/169/head
Paul Mackerras 5 years ago
parent dee3783d79
commit 882a5a0dc0
7 changed files with 607 additions and 1 deletions
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3
tests/mmu/Makefile
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TEST=mmu

include ../Makefile.test

112
tests/mmu/head.S
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/* Copyright 2013-2014 IBM Corp.
*
* 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.
*/

#define STACK_TOP 0x4000

/* Load an immediate 64-bit value into a register */
#define LOAD_IMM64(r, e) \
lis r,(e)@highest; \
ori r,r,(e)@higher; \
rldicr r,r, 32, 31; \
oris r,r, (e)@h; \
ori r,r, (e)@l;

.section ".head","ax"

/*
* Microwatt currently enters in LE mode at 0x0, so we don't need to
* do any endian fix ups
*/
. = 0
.global _start
_start:
b boot_entry

.global boot_entry
boot_entry:
/* setup stack */
LOAD_IMM64(%r1, STACK_TOP - 0x100)
LOAD_IMM64(%r12, main)
mtctr %r12
bctrl
attn // terminate on exit
b .

/* Read a location with translation on */
.globl test_read
test_read:
mfmsr %r9
ori %r8,%r9,0x10 /* set MSR_DR */
mtmsrd %r8,0
mr %r6,%r3
li %r3,0
ld %r5,0(%r6)
li %r3,1
/* land here if DSI occurred */
mtmsrd %r9,0
std %r5,0(%r4)
blr

/* Write a location with translation on */
.globl test_write
test_write:
mfmsr %r9
ori %r8,%r9,0x10 /* set MSR_DR */
mtmsrd %r8,0
mr %r6,%r3
li %r3,0
std %r4,0(%r6)
li %r3,1
/* land here if DSI occurred */
mtmsrd %r9,0
blr

#define EXCEPTION(nr) \
.= nr ;\
attn

/* DSI vector - skip the failing instruction + the next one */
. = 0x300
mtsprg0 %r10
mfsrr0 %r10
addi %r10,%r10,8
mtsrr0 %r10
rfid

/* More exception stubs */
EXCEPTION(0x380)
EXCEPTION(0x400)
EXCEPTION(0x480)
EXCEPTION(0x500)
EXCEPTION(0x600)
EXCEPTION(0x700)
EXCEPTION(0x800)
EXCEPTION(0x900)
EXCEPTION(0x980)
EXCEPTION(0xa00)
EXCEPTION(0xb00)
EXCEPTION(0xc00)
EXCEPTION(0xd00)
EXCEPTION(0xe00)
EXCEPTION(0xe20)
EXCEPTION(0xe40)
EXCEPTION(0xe60)
EXCEPTION(0xe80)
EXCEPTION(0xf00)
EXCEPTION(0xf20)
EXCEPTION(0xf40)
EXCEPTION(0xf60)
EXCEPTION(0xf80)

468
tests/mmu/mmu.c
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#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>

#include "console.h"

extern int test_read(long *addr, long *ret, long init);
extern int test_write(long *addr, long val);

static inline void do_tlbie(unsigned long rb, unsigned long rs)
{
__asm__ volatile("tlbie %0,%1" : : "r" (rb), "r" (rs) : "memory");
}

static inline unsigned long mfspr(int sprnum)
{
long val;

__asm__ volatile("mfspr %0,%1" : "=r" (val) : "i" (sprnum));
return val;
}

static inline void mtspr(int sprnum, unsigned long val)
{
__asm__ volatile("mtspr %0,%1" : : "i" (sprnum), "r" (val));
}

static inline void store_pte(unsigned long *p, unsigned long pte)
{
__asm__ volatile("stdbrx %1,0,%0" : : "r" (p), "r" (pte) : "memory");
}

void print_string(const char *str)
{
for (; *str; ++str)
putchar(*str);
}

void print_hex(unsigned long val)
{
int i, x;

for (i = 60; i >= 0; i -= 4) {
x = (val >> i) & 0xf;
if (x >= 10)
putchar(x + 'a' - 10);
else
putchar(x + '0');
}
}

// i < 100
void print_test_number(int i)
{
print_string("test ");
putchar(48 + i/10);
putchar(48 + i%10);
putchar(':');
}

#define CACHE_LINE_SIZE 64

void zero_memory(void *ptr, unsigned long nbytes)
{
unsigned long nb, i, nl;
void *p;

for (; nbytes != 0; nbytes -= nb, ptr += nb) {
nb = -((unsigned long)ptr) & (CACHE_LINE_SIZE - 1);
if (nb == 0 && nbytes >= CACHE_LINE_SIZE) {
nl = nbytes / CACHE_LINE_SIZE;
p = ptr;
for (i = 0; i < nl; ++i) {
__asm__ volatile("dcbz 0,%0" : : "r" (p) : "memory");
p += CACHE_LINE_SIZE;
}
nb = nl * CACHE_LINE_SIZE;
} else {
if (nb > nbytes)
nb = nbytes;
for (i = 0; i < nb; ++i)
((unsigned char *)ptr)[i] = 0;
}
}
}

#define PERM_EX 0x001
#define PERM_WR 0x002
#define PERM_RD 0x004
#define PERM_PRIV 0x008
#define ATTR_NC 0x020
#define CHG 0x080
#define REF 0x100

#define DFLT_PERM (PERM_WR | PERM_RD | REF | CHG)

/*
* Set up an MMU translation tree using memory starting at the 64k point.
* We use 2 levels, mapping 2GB (the minimum size possible), with a
* 8kB PGD level pointing to 4kB PTE pages.
*/
unsigned long *pgdir = (unsigned long *) 0x10000;
unsigned long free_ptr = 0x12000;
void *eas_mapped[4];
int neas_mapped;

void init_mmu(void)
{
zero_memory(pgdir, 1024 * sizeof(unsigned long));
/* RTS = 0 (2GB address space), RPDS = 10 (1024-entry top level) */
mtspr(720, (unsigned long) pgdir | 10);
do_tlbie(0xc00, 0); /* invalidate all TLB entries */
}

static unsigned long *read_pgd(unsigned long i)
{
unsigned long ret;

__asm__ volatile("ldbrx %0,%1,%2" : "=r" (ret) : "b" (pgdir),
"r" (i * sizeof(unsigned long)));
return (unsigned long *) (ret & 0x00ffffffffffff00);
}

void map(void *ea, void *pa, unsigned long perm_attr)
{
unsigned long epn = (unsigned long) ea >> 12;
unsigned long i, j;
unsigned long *ptep;

i = (epn >> 9) & 0x3ff;
j = epn & 0x1ff;
if (pgdir[i] == 0) {
zero_memory((void *)free_ptr, 512 * sizeof(unsigned long));
store_pte(&pgdir[i], 0x8000000000000000 | free_ptr | 9);
free_ptr += 512 * sizeof(unsigned long);
}
ptep = read_pgd(i);
store_pte(&ptep[j], 0xc000000000000000 | ((unsigned long)pa & 0x00fffffffffff000) | perm_attr);
eas_mapped[neas_mapped++] = ea;
}

void unmap(void *ea)
{
unsigned long epn = (unsigned long) ea >> 12;
unsigned long i, j;
unsigned long *ptep;

i = (epn >> 9) & 0x3ff;
j = epn & 0x1ff;
if (pgdir[i] == 0)
return;
ptep = read_pgd(i);
ptep[j] = 0;
do_tlbie(((unsigned long)ea & ~0xfff), 0);
}

void unmap_all(void)
{
int i;

for (i = 0; i < neas_mapped; ++i)
unmap(eas_mapped[i]);
neas_mapped = 0;
}

int mmu_test_1(void)
{
long *ptr = (long *) 0x123000;
long val;

/* this should fail */
if (test_read(ptr, &val, 0xdeadbeefd00d))
return 1;
/* dest reg of load should be unchanged */
if (val != 0xdeadbeefd00d)
return 2;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != (long) ptr || mfspr(18) != 0x40000000)
return 3;
return 0;
}

int mmu_test_2(void)
{
long *mem = (long *) 0x4000;
long *ptr = (long *) 0x124000;
long *ptr2 = (long *) 0x1124000;
long val;

/* create PTE */
map(ptr, mem, DFLT_PERM);
/* initialize the memory content */
mem[33] = 0xbadc0ffee;
/* this should succeed and be a cache miss */
if (!test_read(&ptr[33], &val, 0xdeadbeefd00d))
return 1;
/* dest reg of load should have the value written */
if (val != 0xbadc0ffee)
return 2;
/* load a second TLB entry in the same set as the first */
map(ptr2, mem, DFLT_PERM);
/* this should succeed and be a cache hit */
if (!test_read(&ptr2[33], &val, 0xdeadbeefd00d))
return 3;
/* dest reg of load should have the value written */
if (val != 0xbadc0ffee)
return 4;
/* check that the first entry still works */
if (!test_read(&ptr[33], &val, 0xdeadbeefd00d))
return 5;
if (val != 0xbadc0ffee)
return 6;
return 0;
}

int mmu_test_3(void)
{
long *mem = (long *) 0x5000;
long *ptr = (long *) 0x149000;
long val;

/* create PTE */
map(ptr, mem, DFLT_PERM);
/* initialize the memory content */
mem[45] = 0xfee1800d4ea;
/* this should succeed and be a cache miss */
if (!test_read(&ptr[45], &val, 0xdeadbeefd0d0))
return 1;
/* dest reg of load should have the value written */
if (val != 0xfee1800d4ea)
return 2;
/* remove the PTE */
unmap(ptr);
/* this should fail */
if (test_read(&ptr[45], &val, 0xdeadbeefd0d0))
return 3;
/* dest reg of load should be unchanged */
if (val != 0xdeadbeefd0d0)
return 4;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != (long) &ptr[45] || mfspr(18) != 0x40000000)
return 5;
return 0;
}

int mmu_test_4(void)
{
long *mem = (long *) 0x6000;
long *ptr = (long *) 0x10a000;
long *ptr2 = (long *) 0x110a000;
long val;

/* create PTE */
map(ptr, mem, DFLT_PERM);
/* initialize the memory content */
mem[27] = 0xf00f00f00f00;
/* this should succeed and be a cache miss */
if (!test_write(&ptr[27], 0xe44badc0ffee))
return 1;
/* memory should now have the value written */
if (mem[27] != 0xe44badc0ffee)
return 2;
/* load a second TLB entry in the same set as the first */
map(ptr2, mem, DFLT_PERM);
/* this should succeed and be a cache hit */
if (!test_write(&ptr2[27], 0x6e11ae))
return 3;
/* memory should have the value written */
if (mem[27] != 0x6e11ae)
return 4;
/* check that the first entry still exists */
/* (assumes TLB is 2-way associative or more) */
if (!test_read(&ptr[27], &val, 0xdeadbeefd00d))
return 5;
if (val != 0x6e11ae)
return 6;
return 0;
}

int mmu_test_5(void)
{
long *mem = (long *) 0x7ffd;
long *ptr = (long *) 0x39fffd;
long val;

/* create PTE */
map(ptr, mem, DFLT_PERM);
/* this should fail */
if (test_read(ptr, &val, 0xdeadbeef0dd0))
return 1;
/* dest reg of load should be unchanged */
if (val != 0xdeadbeef0dd0)
return 2;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != ((long)ptr & ~0xfff) + 0x1000 || mfspr(18) != 0x40000000)
return 3;
return 0;
}

int mmu_test_6(void)
{
long *mem = (long *) 0x7ffd;
long *ptr = (long *) 0x39fffd;

/* create PTE */
map(ptr, mem, DFLT_PERM);
/* initialize memory */
*mem = 0x123456789abcdef0;
/* this should fail */
if (test_write(ptr, 0xdeadbeef0dd0))
return 1;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != ((long)ptr & ~0xfff) + 0x1000 || mfspr(18) != 0x42000000)
return 2;
return 0;
}

int mmu_test_7(void)
{
long *mem = (long *) 0x4000;
long *ptr = (long *) 0x124000;
long val;

*mem = 0x123456789abcdef0;
/* create PTE without R or C */
map(ptr, mem, PERM_RD | PERM_WR);
/* this should fail */
if (test_read(ptr, &val, 0xdeadd00dbeef))
return 1;
/* dest reg of load should be unchanged */
if (val != 0xdeadd00dbeef)
return 2;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != (long) ptr || mfspr(18) != 0x00040000)
return 3;
/* this should fail */
if (test_write(ptr, 0xdeadbeef0dd0))
return 4;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != (long)ptr || mfspr(18) != 0x02040000)
return 5;
/* memory should be unchanged */
if (*mem != 0x123456789abcdef0)
return 6;
return 0;
}

int mmu_test_8(void)
{
long *mem = (long *) 0x4000;
long *ptr = (long *) 0x124000;
long val;

*mem = 0x123456789abcdef0;
/* create PTE with R but not C */
map(ptr, mem, REF | PERM_RD | PERM_WR);
/* this should succeed */
if (!test_read(ptr, &val, 0xdeadd00dbeef))
return 1;
/* this should fail */
if (test_write(ptr, 0xdeadbeef0dd1))
return 2;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != (long)ptr || mfspr(18) != 0x02040000)
return 3;
/* memory should be unchanged */
if (*mem != 0x123456789abcdef0)
return 4;
return 0;
}

int mmu_test_9(void)
{
long *mem = (long *) 0x4000;
long *ptr = (long *) 0x124000;
long val;

*mem = 0x123456789abcdef0;
/* create PTE without read or write permission */
map(ptr, mem, REF);
/* this should fail */
if (test_read(ptr, &val, 0xdeadd00dbeef))
return 1;
/* dest reg of load should be unchanged */
if (val != 0xdeadd00dbeef)
return 2;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != (long) ptr || mfspr(18) != 0x08000000)
return 3;
/* this should fail */
if (test_write(ptr, 0xdeadbeef0dd1))
return 4;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != (long)ptr || mfspr(18) != 0x0a000000)
return 5;
/* memory should be unchanged */
if (*mem != 0x123456789abcdef0)
return 6;
return 0;
}

int mmu_test_10(void)
{
long *mem = (long *) 0x4000;
long *ptr = (long *) 0x124000;
long val;

*mem = 0x123456789abcdef0;
/* create PTE with read but not write permission */
map(ptr, mem, REF | PERM_RD);
/* this should succeed */
if (!test_read(ptr, &val, 0xdeadd00dbeef))
return 1;
/* this should fail */
if (test_write(ptr, 0xdeadbeef0dd1))
return 2;
/* DAR and DSISR should be set correctly */
if (mfspr(19) != (long)ptr || mfspr(18) != 0x0a000000)
return 3;
/* memory should be unchanged */
if (*mem != 0x123456789abcdef0)
return 4;
return 0;
}

int fail = 0;

void do_test(int num, int (*test)(void))
{
int ret;

mtspr(18, 0);
mtspr(19, 0);
unmap_all();
print_test_number(num);
ret = test();
if (ret == 0) {
print_string("PASS\r\n");
} else {
fail = 1;
print_string("FAIL ");
putchar(ret + '0');
print_string(" DAR=");
print_hex(mfspr(19));
print_string(" DSISR=");
print_hex(mfspr(18));
print_string("\r\n");
}
}

int main(void)
{
potato_uart_init();
init_mmu();

do_test(1, mmu_test_1);
do_test(2, mmu_test_2);
do_test(3, mmu_test_3);
do_test(4, mmu_test_4);
do_test(5, mmu_test_5);
do_test(6, mmu_test_6);
do_test(7, mmu_test_7);
do_test(8, mmu_test_8);
do_test(9, mmu_test_9);
do_test(10, mmu_test_10);

return fail;
}

13
tests/mmu/powerpc.lds
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SECTIONS
{
_start = .;
. = 0;
.head : {
KEEP(*(.head))
}
. = 0x1000;
.text : { *(.text) }
. = 0x3000;
.data : { *(.data) }
.bss : { *(.bss) }
}

BIN
tests/test_mmu.bin
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Binary file not shown.

10
tests/test_mmu.console_out
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test 01:PASS
test 02:PASS
test 03:PASS
test 04:PASS
test 05:PASS
test 06:PASS
test 07:PASS
test 08:PASS
test 09:PASS
test 10:PASS

2
tests/update_console_tests
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# Script to update console related tests from source
#

for i in sc illegal decrementer xics privileged ; do
for i in sc illegal decrementer xics privileged mmu ; do
cd $i
make
cd -

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