From: Ali Saidi <Ali.Saidi@ARM.com>
Date: Tue, 13 Sep 2011 17:06:13 +0000 (-0500)
Subject: Prefetch: Don't prefetch if address is in the write queue.
X-Git-Tag: stable_2012_02_02~87
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0c29a97ba90b6416014efee232efd9fea2f974d6;p=gem5.git

Prefetch: Don't prefetch if address is in the write queue.

Check that we're not currently writing back an address the prefetcher is trying
to prefetch before issuing it. We previously checked the mshrQueue and the cache
itself, but forgot to check the writeBuffer. This fixes a memory corrucption
issue with an L2 prefetcher.
---

diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index b29d52f78..a56495abb 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -1437,7 +1437,8 @@ Cache<TagStore>::getNextMSHR()
         PacketPtr pkt = prefetcher->getPacket();
         if (pkt) {
             Addr pf_addr = blockAlign(pkt->getAddr());
-            if (!tags->findBlock(pf_addr) && !mshrQueue.findMatch(pf_addr)) {
+            if (!tags->findBlock(pf_addr) && !mshrQueue.findMatch(pf_addr) &&
+                                             !writeBuffer.findMatch(pf_addr)) {
                 // Update statistic on number of prefetches issued
                 // (hwpf_mshr_misses)
                 mshr_misses[pkt->cmdToIndex()][0/*pkt->req->threadId()*/]++;