Separate page faults from physical memory access exceptions

4 files changed, 25 insertions, 13 deletions

diff --git a/riscv/encoding.h b/riscv/encoding.h
index a7066b7..b07d976 100644
--- a/riscv/encoding.h
+++ b/riscv/encoding.h
@@ -958,17 +958,20 @@
 #define CSR_MHPMCOUNTER30H 0xb9e
 #define CSR_MHPMCOUNTER31H 0xb9f
 #define CAUSE_MISALIGNED_FETCH 0x0
-#define CAUSE_FAULT_FETCH 0x1
+#define CAUSE_FETCH_ACCESS 0x1
 #define CAUSE_ILLEGAL_INSTRUCTION 0x2
 #define CAUSE_BREAKPOINT 0x3
 #define CAUSE_MISALIGNED_LOAD 0x4
-#define CAUSE_FAULT_LOAD 0x5
+#define CAUSE_LOAD_ACCESS 0x5
 #define CAUSE_MISALIGNED_STORE 0x6
-#define CAUSE_FAULT_STORE 0x7
+#define CAUSE_STORE_ACCESS 0x7
 #define CAUSE_USER_ECALL 0x8
 #define CAUSE_SUPERVISOR_ECALL 0x9
 #define CAUSE_HYPERVISOR_ECALL 0xa
 #define CAUSE_MACHINE_ECALL 0xb
+#define CAUSE_FETCH_PAGE_FAULT 0xc
+#define CAUSE_LOAD_PAGE_FAULT 0xd
+#define CAUSE_STORE_PAGE_FAULT 0xf
 #endif
 #ifdef DECLARE_INSN
 DECLARE_INSN(beq, MATCH_BEQ, MASK_BEQ)
@@ -1450,15 +1453,18 @@ DECLARE_CSR(mhpmcounter31h, CSR_MHPMCOUNTER31H)
 #endif
 #ifdef DECLARE_CAUSE
 DECLARE_CAUSE("misaligned fetch", CAUSE_MISALIGNED_FETCH)
-DECLARE_CAUSE("fault fetch", CAUSE_FAULT_FETCH)
+DECLARE_CAUSE("fetch access", CAUSE_FETCH_ACCESS)
 DECLARE_CAUSE("illegal instruction", CAUSE_ILLEGAL_INSTRUCTION)
 DECLARE_CAUSE("breakpoint", CAUSE_BREAKPOINT)
 DECLARE_CAUSE("misaligned load", CAUSE_MISALIGNED_LOAD)
-DECLARE_CAUSE("fault load", CAUSE_FAULT_LOAD)
+DECLARE_CAUSE("load access", CAUSE_LOAD_ACCESS)
 DECLARE_CAUSE("misaligned store", CAUSE_MISALIGNED_STORE)
-DECLARE_CAUSE("fault store", CAUSE_FAULT_STORE)
+DECLARE_CAUSE("store access", CAUSE_STORE_ACCESS)
 DECLARE_CAUSE("user_ecall", CAUSE_USER_ECALL)
 DECLARE_CAUSE("supervisor_ecall", CAUSE_SUPERVISOR_ECALL)
 DECLARE_CAUSE("hypervisor_ecall", CAUSE_HYPERVISOR_ECALL)
 DECLARE_CAUSE("machine_ecall", CAUSE_MACHINE_ECALL)
+DECLARE_CAUSE("fetch page fault", CAUSE_FETCH_PAGE_FAULT)
+DECLARE_CAUSE("load page fault", CAUSE_LOAD_PAGE_FAULT)
+DECLARE_CAUSE("store page fault", CAUSE_STORE_PAGE_FAULT)
 #endif
diff --git a/riscv/mmu.cc b/riscv/mmu.cc
index 0b28f2f..8df38e5 100644
--- a/riscv/mmu.cc
+++ b/riscv/mmu.cc
@@ -180,7 +180,7 @@ reg_t mmu_t::walk(reg_t addr, access_type type, reg_t mode)
     // check that physical address of PTE is legal
     reg_t pte_addr = base + idx * vm.ptesize;
     if (!sim->addr_is_mem(pte_addr))
-      break;
+      throw trap_load_access_fault(addr);
 
     void* ppte = sim->addr_to_mem(pte_addr);
     reg_t pte = vm.ptesize == 4 ? *(uint32_t*)ppte : *(uint64_t*)ppte;
@@ -215,9 +215,9 @@ reg_t mmu_t::walk(reg_t addr, access_type type, reg_t mode)
 
 fail:
   switch (type) {
-    case FETCH: throw trap_instruction_access_fault(addr);
-    case LOAD: throw trap_load_access_fault(addr);
-    case STORE: throw trap_store_access_fault(addr);
+    case FETCH: throw trap_instruction_page_fault(addr);
+    case LOAD: throw trap_load_page_fault(addr);
+    case STORE: throw trap_store_page_fault(addr);
     default: abort();
   }
 }
diff --git a/riscv/mmu.h b/riscv/mmu.h
index 9365457..66454be 100644
--- a/riscv/mmu.h
+++ b/riscv/mmu.h
@@ -115,6 +115,9 @@ public:
         auto lhs = load_##type(addr); \
         store_##type(addr, f(lhs)); \
         return lhs; \
+      } catch (trap_load_page_fault& t) { \
+        /* AMO faults should be reported as store faults */ \
+        throw trap_store_page_fault(t.get_badaddr()); \
       } catch (trap_load_access_fault& t) { \
         /* AMO faults should be reported as store faults */ \
         throw trap_store_access_fault(t.get_badaddr()); \
diff --git a/riscv/trap.h b/riscv/trap.h
index 7f35c5f..a289a68 100644
--- a/riscv/trap.h
+++ b/riscv/trap.h
@@ -45,16 +45,19 @@ class mem_trap_t : public trap_t
 };
 
 DECLARE_MEM_TRAP(CAUSE_MISALIGNED_FETCH, instruction_address_misaligned)
-DECLARE_MEM_TRAP(CAUSE_FAULT_FETCH, instruction_access_fault)
+DECLARE_MEM_TRAP(CAUSE_FETCH_ACCESS, instruction_access_fault)
 DECLARE_TRAP(CAUSE_ILLEGAL_INSTRUCTION, illegal_instruction)
 DECLARE_TRAP(CAUSE_BREAKPOINT, breakpoint)
 DECLARE_MEM_TRAP(CAUSE_MISALIGNED_LOAD, load_address_misaligned)
 DECLARE_MEM_TRAP(CAUSE_MISALIGNED_STORE, store_address_misaligned)
-DECLARE_MEM_TRAP(CAUSE_FAULT_LOAD, load_access_fault)
-DECLARE_MEM_TRAP(CAUSE_FAULT_STORE, store_access_fault)
+DECLARE_MEM_TRAP(CAUSE_LOAD_ACCESS, load_access_fault)
+DECLARE_MEM_TRAP(CAUSE_STORE_ACCESS, store_access_fault)
 DECLARE_TRAP(CAUSE_USER_ECALL, user_ecall)
 DECLARE_TRAP(CAUSE_SUPERVISOR_ECALL, supervisor_ecall)
 DECLARE_TRAP(CAUSE_HYPERVISOR_ECALL, hypervisor_ecall)
 DECLARE_TRAP(CAUSE_MACHINE_ECALL, machine_ecall)
+DECLARE_MEM_TRAP(CAUSE_FETCH_PAGE_FAULT, instruction_page_fault)
+DECLARE_MEM_TRAP(CAUSE_LOAD_PAGE_FAULT, load_page_fault)
+DECLARE_MEM_TRAP(CAUSE_STORE_PAGE_FAULT, store_page_fault)
 
 #endif