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-rw-r--r--src/mem/cache/cache_impl.hh38
1 files changed, 22 insertions, 16 deletions
diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index 29285abce..14e49e1f7 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -1966,10 +1966,28 @@ Cache<TagStore>::getTimingPacket()
snoop_pkt.senderState = mshr;
cpuSidePort->sendTimingSnoopReq(&snoop_pkt);
- // Check to see if the prefetch was squashed by an upper
- // cache (to prevent us from grabbing the line) or if a
- // writeback arrived between the time the prefetch was
- // placed in the MSHRs and when it was selected to be sent.
+ // Check to see if the prefetch was squashed by an upper cache (to
+ // prevent us from grabbing the line) or if a Check to see if a
+ // writeback arrived between the time the prefetch was placed in
+ // the MSHRs and when it was selected to be sent or if the
+ // prefetch was squashed by an upper cache.
+
+ // It is important to check msmInhibitAsserted before
+ // prefetchSquashed. If another cache has asserted MEM_INGIBIT, it
+ // will be sending a response which will arrive at the MSHR
+ // allocated ofr this request. Checking the prefetchSquash first
+ // may result in the MSHR being prematurely deallocated.
+
+ if (snoop_pkt.memInhibitAsserted()) {
+ // If we are getting a non-shared response it is dirty
+ bool pending_dirty_resp = !snoop_pkt.sharedAsserted();
+ markInService(mshr, pending_dirty_resp);
+ DPRINTF(Cache, "Upward snoop of prefetch for addr"
+ " %#x (%s) hit\n",
+ tgt_pkt->getAddr(), tgt_pkt->isSecure()? "s": "ns");
+ return NULL;
+ }
+
if (snoop_pkt.prefetchSquashed() || blk != NULL) {
DPRINTF(Cache, "Prefetch squashed by cache. "
"Deallocating mshr target %#x.\n", mshr->addr);
@@ -1983,18 +2001,6 @@ Cache<TagStore>::getTimingPacket()
return NULL;
}
- // Check if the prefetch hit a writeback in an upper cache
- // and if so we will eventually get a HardPFResp from
- // above
- if (snoop_pkt.memInhibitAsserted()) {
- // If we are getting a non-shared response it is dirty
- bool pending_dirty_resp = !snoop_pkt.sharedAsserted();
- markInService(mshr, pending_dirty_resp);
- DPRINTF(Cache, "Upward snoop of prefetch for addr"
- " %#x (%s) hit\n",
- tgt_pkt->getAddr(), tgt_pkt->isSecure()? "s": "ns");
- return NULL;
- }
}
pkt = getBusPacket(tgt_pkt, blk, mshr->needsExclusive());