Merge pull request #150 from comparch-security/fix-evict

Permission needs to be elevated during eviction
comparch-security · Sep 15, 2024 · 6a640b9 · 6a640b9
2 parents 9eefce6 + 95e7534
commit 6a640b9
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/cache/coherence.hpp b/cache/coherence.hpp
@@ -174,7 +174,7 @@ class OuterCohPortT : public OPUC<Policy, EnMT, Extra...>
         hit = cache->hit(addr, &ai, &s, &w, XactPrio::probe, true);
         if(hit) {
           std::tie(meta, data) = cache->access_line(ai, s, w); meta->lock();
-          if(!meta->match(addr)) { // cache line is invalidated potentially by a simultaneous acquire
+          if(!cache->check_mt_state(ai, s, XactPrio::probe) || !meta->match(addr)) { // cache line is invalidated potentially by a simultaneous acquire
             meta->unlock(); meta = nullptr; data = nullptr;
             cache->reset_mt_state(ai, s, XactPrio::probe); continue; // redo the hit check
           }
@@ -254,6 +254,7 @@ class InnerCohPortUncached : public InnerCohPortBase
     // evict a block due to conflict
     auto addr = meta->addr(s);
     assert(cache->hit(addr));
+    if constexpr (EnMT && Policy::evict_need_lock()) cache->set_mt_state(ai, s, XactPrio::evict);
     auto sync = Policy::writeback_need_sync(meta);
     if(sync.first) {
       auto [phit, pwb] = probe_req(addr, meta, data, sync.second, delay); // sync if necessary
@@ -263,6 +264,7 @@ class InnerCohPortUncached : public InnerCohPortBase
     if(writeback.first) outer->writeback_req(addr, meta, data, writeback.second, delay); // writeback if dirty
     Policy::meta_after_evict(meta);
     cache->hook_manage(addr, ai, s, w, true, true, writeback.first, meta, data, delay);
+    if constexpr (EnMT && Policy::evict_need_lock()) cache->reset_mt_state(ai, s, XactPrio::evict);
   }
 
   virtual std::tuple<bool, CMMetadataBase *, CMDataBase *, uint32_t, uint32_t, uint32_t>
@@ -344,6 +346,7 @@ class InnerCohPortUncached : public InnerCohPortBase
       auto [probe, probe_cmd] = Policy::flush_need_sync(cmd, meta);
       if(!hit) return;
 
+      if constexpr (EnMT && Policy::evict_need_lock()) cache->set_mt_state(ai, s, XactPrio::evict);
       if(probe) {
         auto [phit, pwb] = probe_req(addr, meta, data, probe_cmd, delay); // sync if necessary
         if(pwb) cache->hook_write(addr, ai, s, w, true, false, meta, data, delay); // a write occurred during the probe
@@ -355,7 +358,10 @@ class InnerCohPortUncached : public InnerCohPortBase
       Policy::meta_after_flush(cmd, meta, cache);
       cache->hook_manage(addr, ai, s, w, hit, coh::is_evict(cmd), writeback.first, meta, data, delay);
 
-      if constexpr (EnMT) { meta->unlock(); cache->reset_mt_state(ai, s, XactPrio::flush); }
+      if constexpr (EnMT) { 
+        if constexpr (Policy::evict_need_lock()) cache->reset_mt_state(ai, s, XactPrio::evict);
+        meta->unlock(); cache->reset_mt_state(ai, s, XactPrio::flush); 
+      }
     }
   }
 

diff --git a/cache/mi.hpp b/cache/mi.hpp
@@ -21,6 +21,8 @@ struct MIPolicy : public CohPolicyBase
 {
   constexpr static __always_inline bool is_uncached() { return uncached; }
 
+  constexpr static __always_inline bool evict_need_lock() { return !(uncached || isL1); }
+
   static __always_inline coh_cmd_t cmd_for_outer_acquire(coh_cmd_t cmd) { return coh::cmd_for_write(); }
 
   static __always_inline std::pair<bool, coh_cmd_t> access_need_sync(coh_cmd_t cmd, const CMMetadataBase *meta) {