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mem: Fix MSHR assert triggering for invalidated prefetches

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This changeset updates an assert in src/mem/cache/mshr.cc which was
erroneously catching invalidated prefetch requests. These requests can
become invalidated if another component writes (an exclusive access)
to this location during the time that the read request is in
flight. The original assert made the assumption that these cases can
only occur for reads generated by the CPU, and hence
prefetcher-generated requests would sometimes trip the assert.

Change-Id: If4f043273a688c2bab8f7a641192a2b583e7b20e
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
This commit is contained in:
Sascha Bischoff 2017-02-21 14:14:44 +00:00
parent 767aed4534
commit 46b4c40277
1 changed files with 3 additions and 2 deletions
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5
src/mem/cache/mshr.cc vendored
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@ -1,5 +1,5 @@
/* /*
* Copyright (c) 2012-2013, 2015-2016 ARM Limited * Copyright (c) 2012-2013, 2015-2017 ARM Limited
* All rights reserved. * All rights reserved.
* *
* The license below extends only to copyright in the software and shall * The license below extends only to copyright in the software and shall
@ -465,7 +465,8 @@ MSHR::extractServiceableTargets(PacketPtr pkt)
// avoid memory consistency violations. // avoid memory consistency violations.
if (pkt->cmd == MemCmd::ReadRespWithInvalidate) { if (pkt->cmd == MemCmd::ReadRespWithInvalidate) {
auto it = targets.begin(); auto it = targets.begin();
assert(it->source == Target::FromCPU); assert((it->source == Target::FromCPU) ||
(it->source == Target::FromPrefetcher));
ready_targets.push_back(*it); ready_targets.push_back(*it);
it = targets.erase(it); it = targets.erase(it);
while (it != targets.end()) { while (it != targets.end()) {