Merge pull request #976 from rbuchner-aril/amo-attr-fix

Fix for #873 AMO exception priorities

riscv/mmu.cc

@@ -161,7 +161,7 @@ void mmu_t::load_slow_path(reg_t addr, reg_t len, uint8_t* bytes, uint32_t xlate
   }
 }
 
-void mmu_t::store_slow_path(reg_t addr, reg_t len, const uint8_t* bytes, uint32_t xlate_flags)
+void mmu_t::store_slow_path(reg_t addr, reg_t len, const uint8_t* bytes, uint32_t xlate_flags, bool actually_store)
 {
   reg_t paddr = translate(addr, len, STORE, xlate_flags);
 
@@ -172,14 +172,16 @@ void mmu_t::store_slow_path(reg_t addr, reg_t len, const uint8_t* bytes, uint32_
       throw *matched_trigger;
   }
 
-  if (auto host_addr = sim->addr_to_mem(paddr)) {
-    memcpy(host_addr, bytes, len);
-    if (tracer.interested_in_range(paddr, paddr + PGSIZE, STORE))
-      tracer.trace(paddr, len, STORE);
-    else if (xlate_flags == 0)
-      refill_tlb(addr, paddr, host_addr, STORE);
-  } else if (!mmio_store(paddr, len, bytes)) {
-    throw trap_store_access_fault((proc) ? proc->state.v : false, addr, 0, 0);
+  if (actually_store) {
+    if (auto host_addr = sim->addr_to_mem(paddr)) {
+      memcpy(host_addr, bytes, len);
+      if (tracer.interested_in_range(paddr, paddr + PGSIZE, STORE))
+        tracer.trace(paddr, len, STORE);
+      else if (xlate_flags == 0)
+        refill_tlb(addr, paddr, host_addr, STORE);
+    } else if (!mmio_store(paddr, len, bytes)) {
+      throw trap_store_access_fault((proc) ? proc->state.v : false, addr, 0, 0);
+    }
   }
 }
 

riscv/mmu.h

@@ -147,28 +147,32 @@ public:
 
   // template for functions that store an aligned value to memory
   #define store_func(type, prefix, xlate_flags) \
-    void prefix##_##type(reg_t addr, type##_t val) { \
+    void prefix##_##type(reg_t addr, type##_t val, bool actually_store=true) {   \
       if (unlikely(addr & (sizeof(type##_t)-1))) \
         return misaligned_store(addr, val, sizeof(type##_t), xlate_flags); \
       reg_t vpn = addr >> PGSHIFT; \
       size_t size = sizeof(type##_t); \
       if ((xlate_flags) == 0 && likely(tlb_store_tag[vpn % TLB_ENTRIES] == vpn)) { \
-        if (proc) WRITE_MEM(addr, val, size); \
-        *(target_endian<type##_t>*)(tlb_data[vpn % TLB_ENTRIES].host_offset + addr) = to_target(val); \
+        if (actually_store) { \
+          if (proc) WRITE_MEM(addr, val, size); \
+          *(target_endian<type##_t>*)(tlb_data[vpn % TLB_ENTRIES].host_offset + addr) = to_target(val); \
+        } \
       } \
       else if ((xlate_flags) == 0 && unlikely(tlb_store_tag[vpn % TLB_ENTRIES] == (vpn | TLB_CHECK_TRIGGERS))) { \
-        if (!matched_trigger) { \
-          matched_trigger = trigger_exception(triggers::OPERATION_STORE, addr, val); \
-          if (matched_trigger) \
-            throw *matched_trigger; \
+        if (actually_store) { \
+          if (!matched_trigger) { \
+            matched_trigger = trigger_exception(triggers::OPERATION_STORE, addr, val); \
+            if (matched_trigger) \
+              throw *matched_trigger; \
+          } \
+          if (proc) WRITE_MEM(addr, val, size); \
+          *(target_endian<type##_t>*)(tlb_data[vpn % TLB_ENTRIES].host_offset + addr) = to_target(val); \
         } \
-        if (proc) WRITE_MEM(addr, val, size); \
-        *(target_endian<type##_t>*)(tlb_data[vpn % TLB_ENTRIES].host_offset + addr) = to_target(val); \
       } \
       else { \
         target_endian<type##_t> target_val = to_target(val); \
-        store_slow_path(addr, sizeof(type##_t), (const uint8_t*)&target_val, (xlate_flags)); \
-        if (proc) WRITE_MEM(addr, val, size); \
+        store_slow_path(addr, sizeof(type##_t), (const uint8_t*)&target_val, (xlate_flags), actually_store); \
+        if (actually_store && proc) WRITE_MEM(addr, val, size); \
       } \
   }
 
@@ -192,6 +196,7 @@ public:
     template<typename op> \
     type##_t amo_##type(reg_t addr, op f) { \
       convert_load_traps_to_store_traps({ \
+        store_##type(addr, 0, false); \
         auto lhs = load_##type(addr, true); \
         store_##type(addr, f(lhs)); \
         return lhs; \
@@ -438,7 +443,7 @@ private:
   // handle uncommon cases: TLB misses, page faults, MMIO
   tlb_entry_t fetch_slow_path(reg_t addr);
   void load_slow_path(reg_t addr, reg_t len, uint8_t* bytes, uint32_t xlate_flags);
-  void store_slow_path(reg_t addr, reg_t len, const uint8_t* bytes, uint32_t xlate_flags);
+  void store_slow_path(reg_t addr, reg_t len, const uint8_t* bytes, uint32_t xlate_flags, bool actually_store);
   bool mmio_load(reg_t addr, size_t len, uint8_t* bytes);
   bool mmio_store(reg_t addr, size_t len, const uint8_t* bytes);
   bool mmio_ok(reg_t addr, access_type type);