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-rwxr-xr-xsrc/mem/snoop_filter.cc32
1 files changed, 19 insertions, 13 deletions
diff --git a/src/mem/snoop_filter.cc b/src/mem/snoop_filter.cc
index 636861c2b..14cdc7e07 100755
--- a/src/mem/snoop_filter.cc
+++ b/src/mem/snoop_filter.cc
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2013-2015 ARM Limited
+ * Copyright (c) 2013-2016 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
@@ -65,9 +65,9 @@ SnoopFilter::lookupRequest(const Packet* cpkt, const SlavePort& slave_port)
DPRINTF(SnoopFilter, "%s: packet src %s addr 0x%x cmd %s\n",
__func__, slave_port.name(), cpkt->getAddr(), cpkt->cmdString());
- // Ultimately we should check if the packet came from an
- // allocating source, not just if the port is snooping
- bool allocate = !cpkt->req->isUncacheable() && slave_port.isSnooping();
+ // check if the packet came from a cache
+ bool allocate = !cpkt->req->isUncacheable() && slave_port.isSnooping() &&
+ cpkt->fromCache();
Addr line_addr = cpkt->getBlockAddr(linesize);
SnoopMask req_port = portToMask(slave_port);
reqLookupResult = cachedLocations.find(line_addr);
@@ -235,11 +235,12 @@ SnoopFilter::updateSnoopResponse(const Packet* cpkt,
assert(cpkt->isResponse());
assert(cpkt->cacheResponding());
- // Ultimately we should check if the packet came from an
- // allocating source, not just if the port is snooping
- bool allocate = !cpkt->req->isUncacheable() && req_port.isSnooping();
- if (!allocate)
+ // if this snoop response is due to an uncacheable request, or is
+ // being turned into a normal response, there is nothing more to
+ // do
+ if (cpkt->req->isUncacheable() || !req_port.isSnooping()) {
return;
+ }
Addr line_addr = cpkt->getBlockAddr(linesize);
SnoopMask rsp_mask = portToMask(rsp_port);
@@ -268,6 +269,7 @@ SnoopFilter::updateSnoopResponse(const Packet* cpkt,
sf_item.holder = 0;
}
assert(!cpkt->isWriteback());
+ // @todo Deal with invalidating responses
sf_item.holder |= req_mask;
sf_item.requested &= ~req_mask;
assert(sf_item.requested | sf_item.holder);
@@ -319,15 +321,19 @@ SnoopFilter::updateResponse(const Packet* cpkt, const SlavePort& slave_port)
assert(cpkt->isResponse());
- // Ultimately we should check if the packet came from an
- // allocating source, not just if the port is snooping
- bool allocate = !cpkt->req->isUncacheable() && slave_port.isSnooping();
- if (!allocate)
+ // we only allocate if the packet actually came from a cache, but
+ // start by checking if the port is snooping
+ if (cpkt->req->isUncacheable() || !slave_port.isSnooping())
return;
+ // next check if we actually allocated an entry
Addr line_addr = cpkt->getBlockAddr(linesize);
+ auto sf_it = cachedLocations.find(line_addr);
+ if (sf_it == cachedLocations.end())
+ return;
+
SnoopMask slave_mask = portToMask(slave_port);
- SnoopItem& sf_item = cachedLocations[line_addr];
+ SnoopItem& sf_item = sf_it->second;
DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n",
__func__, sf_item.requested, sf_item.holder);