diff options
Diffstat (limited to 'src/mem')
| -rw-r--r-- | src/mem/cache/base.cc | 24 | ||||
| -rw-r--r-- | src/mem/cache/cache.cc | 26 |
2 files changed, 26 insertions, 24 deletions
diff --git a/src/mem/cache/base.cc b/src/mem/cache/base.cc index 082650c09..0de7f2150 100644 --- a/src/mem/cache/base.cc +++ b/src/mem/cache/base.cc @@ -1409,30 +1409,6 @@ BaseCache::handleFill(PacketPtr pkt, CacheBlk *blk, PacketList &writebacks, chatty_assert(!isReadOnly, "Should never see dirty snoop response " "in read-only cache %s\n", name()); - } else if (pkt->cmd.isSWPrefetch() && pkt->needsWritable()) { - // All other copies of the block were invalidated and we - // have an exclusive copy. - - // The coherence protocol assumes that if we fetched an - // exclusive copy of the block, we have the intention to - // modify it. Therefore the MSHR for the PrefetchExReq has - // been the point of ordering and this cache has commited - // to respond to snoops for the block. - // - // In most cases this is true anyway - a PrefetchExReq - // will be followed by a WriteReq. However, if that - // doesn't happen, the block is not marked as dirty and - // the cache doesn't respond to snoops that has committed - // to do so. - // - // To avoid deadlocks in cases where there is a snoop - // between the PrefetchExReq and the expected WriteReq, we - // proactively mark the block as Dirty. - - blk->status |= BlkDirty; - - panic_if(!isReadOnly, "Prefetch exclusive requests from read-only " - "cache %s\n", name()); } } diff --git a/src/mem/cache/cache.cc b/src/mem/cache/cache.cc index bded74643..b054cd43d 100644 --- a/src/mem/cache/cache.cc +++ b/src/mem/cache/cache.cc @@ -710,6 +710,32 @@ Cache::serviceMSHRTargets(MSHR *mshr, const PacketPtr pkt, CacheBlk *blk) // Software prefetch handling for cache closest to core if (tgt_pkt->cmd.isSWPrefetch()) { + if (tgt_pkt->needsWritable()) { + // All other copies of the block were invalidated and we + // have an exclusive copy. + + // The coherence protocol assumes that if we fetched an + // exclusive copy of the block, we have the intention to + // modify it. Therefore the MSHR for the PrefetchExReq has + // been the point of ordering and this cache has commited + // to respond to snoops for the block. + // + // In most cases this is true anyway - a PrefetchExReq + // will be followed by a WriteReq. However, if that + // doesn't happen, the block is not marked as dirty and + // the cache doesn't respond to snoops that has committed + // to do so. + // + // To avoid deadlocks in cases where there is a snoop + // between the PrefetchExReq and the expected WriteReq, we + // proactively mark the block as Dirty. + assert(blk); + blk->status |= BlkDirty; + + panic_if(isReadOnly, "Prefetch exclusive requests from " + "read-only cache %s\n", name()); + } + // a software prefetch would have already been ack'd // immediately with dummy data so the core would be able to // retire it. This request completes right here, so we |