From 70270c066a0fbcce74ffe866199973fe937d7aea Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Sat, 25 Sep 2021 13:18:59 +1000 Subject: [PATCH] dcache: Fix bug with dcbz closely following stores with the same tag This fixes a bug where a dcbz can get incorrectly handled as an ordinary 8-byte store if it arrives while the dcache state machine is handling other stores with the same tag value (i.e. within the same set-sized area of memory). The logic that says whether to include a new store in the current wishbone cycle didn't take into account whether the new store was a dcbz. This adds a "req.dcbz = '0'" factor so that it does. This is necessary because dcbz is handled more like a cache line refill (but writing to memory rather than reading) than an ordinary store. Signed-off-by: Paul Mackerras --- dcache.vhdl | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/dcache.vhdl b/dcache.vhdl index 705393a..34dbda2 100644 --- a/dcache.vhdl +++ b/dcache.vhdl @@ -1537,7 +1537,7 @@ begin r1.wb.dat <= req.data; r1.wb.sel <= req.byte_sel; end if; - if acks < 7 and req.same_tag = '1' and + if acks < 7 and req.same_tag = '1' and req.dcbz = '0' and (req.op = OP_STORE_MISS or req.op = OP_STORE_HIT) then r1.wb.stb <= '1'; stbs_done := false;