diff options
Diffstat (limited to 'src/mem/cache/cache.cc')
| -rw-r--r-- | src/mem/cache/cache.cc | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/src/mem/cache/cache.cc b/src/mem/cache/cache.cc index ecdf4c855..991463d76 100644 --- a/src/mem/cache/cache.cc +++ b/src/mem/cache/cache.cc @@ -1904,6 +1904,13 @@ Cache::handleSnoop(PacketPtr pkt, CacheBlk *blk, bool is_timing, bool invalidate = pkt->isInvalidate(); bool M5_VAR_USED needs_writable = pkt->needsWritable(); + // at the moment we could get an uncacheable write which does not + // have the invalidate flag, and we need a suitable way of dealing + // with this case + panic_if(invalidate && pkt->req->isUncacheable(), + "%s got an invalidating uncacheable snoop request %s to %#llx", + name(), pkt->cmdString(), pkt->getAddr()); + uint32_t snoop_delay = 0; if (forwardSnoops) { @@ -1988,15 +1995,18 @@ Cache::handleSnoop(PacketPtr pkt, CacheBlk *blk, bool is_timing, return snoop_delay; } - if (!pkt->req->isUncacheable() && pkt->isRead() && !invalidate) { - // reading without requiring the line in a writable state, - // note that we retain the block as Owned if it is Modified - // (dirty data), with the response taken care of below, and - // otherwhise simply downgrade from Exclusive to Shared (or - // remain in Shared) + if (pkt->isRead() && !invalidate) { + // reading without requiring the line in a writable state assert(!needs_writable); pkt->setHasSharers(); - blk->status &= ~BlkWritable; + + // if the requesting packet is uncacheable, retain the line in + // the current state, otherwhise unset the writable flag, + // which means we go from Modified to Owned (and will respond + // below), remain in Owned (and will respond below), from + // Exclusive to Shared, or remain in Shared + if (!pkt->req->isUncacheable()) + blk->status &= ~BlkWritable; } if (respond) { @@ -2020,6 +2030,13 @@ Cache::handleSnoop(PacketPtr pkt, CacheBlk *blk, bool is_timing, // we already called setHasSharers above } + // if we are returning a writable and dirty (Modified) line, + // we should be invalidating the line + panic_if(!invalidate && !pkt->hasSharers(), + "%s is passing a Modified line through %s to %#llx, " + "but keeping the block", + name(), pkt->cmdString(), pkt->getAddr()); + if (is_timing) { doTimingSupplyResponse(pkt, blk->data, is_deferred, pending_inval); } else { |