commit 98f21c30f5beffc45232721ae79c019df58ae9f1
author Deepak Gupta <debug@rivosinc.com> Tue Oct 08 15:50:04 2024 -0700
committer Alistair Francis <alistair.francis@wdc.com> Wed Oct 30 11:22:08 2024 +1000
tree ee399f300ec737fbb37a7f5abf717a61209a4810
parent 669b4867495c48cfb302c6500de99f79d38802b6

target/riscv: AMO operations always raise store/AMO fault

This patch adds one more word for tcg compile which can be obtained during
unwind time to determine fault type for original operation (example AMO).
Depending on that, fault can be promoted to store/AMO fault.

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20241008225010.1861630-15-debug@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.h

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 47e7a91..284b112 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -46,8 +46,13 @@
 /*
  * RISC-V-specific extra insn start words:
  * 1: Original instruction opcode
+ * 2: more information about instruction
  */
-#define TARGET_INSN_START_EXTRA_WORDS 1
+#define TARGET_INSN_START_EXTRA_WORDS 2
+/*
+ * b0: Whether a instruction always raise a store AMO or not.
+ */
+#define RISCV_UW2_ALWAYS_STORE_AMO 1
 
 #define RV(x) ((target_ulong)1 << (x - 'A'))
 
@@ -234,6 +239,8 @@
     bool      elp;
     /* shadow stack register for zicfiss extension */
     target_ulong ssp;
+    /* env place holder for extra word 2 during unwind */
+    target_ulong excp_uw2;
     /* sw check code for sw check exception */
     target_ulong sw_check_code;
 #ifdef CONFIG_USER_ONLY

target/riscv/cpu_helper.c

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 42177a5..0a3ead6 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -1764,6 +1764,22 @@
     return xinsn;
 }
 
+static target_ulong promote_load_fault(target_ulong orig_cause)
+{
+    switch (orig_cause) {
+    case RISCV_EXCP_LOAD_GUEST_ACCESS_FAULT:
+        return RISCV_EXCP_STORE_GUEST_AMO_ACCESS_FAULT;
+
+    case RISCV_EXCP_LOAD_ACCESS_FAULT:
+        return RISCV_EXCP_STORE_AMO_ACCESS_FAULT;
+
+    case RISCV_EXCP_LOAD_PAGE_FAULT:
+        return RISCV_EXCP_STORE_PAGE_FAULT;
+    }
+
+    /* if no promotion, return original cause */
+    return orig_cause;
+}
 /*
  * Handle Traps
  *
@@ -1776,6 +1792,7 @@
     CPURISCVState *env = &cpu->env;
     bool virt = env->virt_enabled;
     bool write_gva = false;
+    bool always_storeamo = (env->excp_uw2 & RISCV_UW2_ALWAYS_STORE_AMO);
     uint64_t s;
 
     /*
@@ -1813,6 +1830,9 @@
         case RISCV_EXCP_STORE_AMO_ACCESS_FAULT:
         case RISCV_EXCP_LOAD_PAGE_FAULT:
         case RISCV_EXCP_STORE_PAGE_FAULT:
+            if (always_storeamo) {
+                cause = promote_load_fault(cause);
+            }
             write_gva = env->two_stage_lookup;
             tval = env->badaddr;
             if (env->two_stage_indirect_lookup) {

target/riscv/tcg/tcg-cpu.c

diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index 6c0c319..c62c221 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -129,6 +129,7 @@
         env->pc = pc;
     }
     env->bins = data[1];
+    env->excp_uw2 = data[2];
 }
 
 static const TCGCPUOps riscv_tcg_ops = {

target/riscv/translate.c

diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index afa2ed4..0322597 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -1264,7 +1264,7 @@
         pc_next &= ~TARGET_PAGE_MASK;
     }
 
-    tcg_gen_insn_start(pc_next, 0);
+    tcg_gen_insn_start(pc_next, 0, 0);
     ctx->insn_start_updated = false;
 }