From 64bf90dca3b050591386cfc09121a54733f57706 Mon Sep 17 00:00:00 2001 From: Gabe Black Date: Tue, 24 Apr 2012 00:48:41 -0700 Subject: [PATCH] X86: Clear out duplicate TLB entries when adding a new one. It's possible for two page table walks to overlap which will go in the same place in the TLB's trie. They would land on top of each other, so this change adds some code which detects if an address already matches an entry and if so throws away the new one. --- src/arch/x86/tlb.cc | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/src/arch/x86/tlb.cc b/src/arch/x86/tlb.cc index caa3efc1e..8dad84dc4 100644 --- a/src/arch/x86/tlb.cc +++ b/src/arch/x86/tlb.cc @@ -98,11 +98,16 @@ TLB::evictLRU() TlbEntry * TLB::insert(Addr vpn, TlbEntry &entry) { - //TODO Deal with conflicting entries + // If somebody beat us to it, just use that existing entry. + TlbEntry *newEntry = trie.lookup(vpn); + if (newEntry) { + assert(newEntry->vaddr = vpn); + return newEntry; + } - TlbEntry *newEntry = NULL; if (freeList.empty()) evictLRU(); + newEntry = freeList.front(); freeList.pop_front(); @@ -110,7 +115,7 @@ TLB::insert(Addr vpn, TlbEntry &entry) newEntry->lruSeq = nextSeq(); newEntry->vaddr = vpn; newEntry->trieHandle = - trie.insert(vpn, TlbEntryTrie::MaxBits - entry.logBytes, newEntry); + trie.insert(vpn, TlbEntryTrie::MaxBits - entry.logBytes, newEntry); return newEntry; } -- 2.30.2