target/riscv: do not call GETPC() in check_ret_from_m_mode()

GETPC() should always be called from the top level helper, e.g. the
first helper that is called by the translation code. We stopped doing
that in commit 3157a553ec, and then we introduced problems when
unwinding the exceptions being thrown by helper_mret(), as reported by
[1].

Call GETPC() at the top level helper and pass the value along.

[1] https://gitlab.com/qemu-project/qemu/-/issues/3020

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Fixes: 3157a553ec ("target/riscv: Add Smrnmi mnret instruction")
Closes: https://gitlab.com/qemu-project/qemu/-/issues/3020
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Nutty Liu <liujingqi@lanxincomputing.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250714133739.1248296-1-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index 15460bf..110292e 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -355,21 +355,22 @@ target_ulong helper_sret(CPURISCVState *env)
 }
 
 static void check_ret_from_m_mode(CPURISCVState *env, target_ulong retpc,
-                                  target_ulong prev_priv)
+                                  target_ulong prev_priv,
+                                  uintptr_t ra)
 {
     if (!(env->priv >= PRV_M)) {
-        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
+        riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, ra);
     }
 
     if (!riscv_cpu_allow_16bit_insn(&env_archcpu(env)->cfg,
                                     env->priv_ver,
                                     env->misa_ext) && (retpc & 0x3)) {
-        riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, GETPC());
+        riscv_raise_exception(env, RISCV_EXCP_INST_ADDR_MIS, ra);
     }
 
     if (riscv_cpu_cfg(env)->pmp &&
         !pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
-        riscv_raise_exception(env, RISCV_EXCP_INST_ACCESS_FAULT, GETPC());
+        riscv_raise_exception(env, RISCV_EXCP_INST_ACCESS_FAULT, ra);
     }
 }
 static target_ulong ssdbltrp_mxret(CPURISCVState *env, target_ulong mstatus,
@@ -394,8 +395,9 @@ target_ulong helper_mret(CPURISCVState *env)
     target_ulong retpc = env->mepc & get_xepc_mask(env);
     uint64_t mstatus = env->mstatus;
     target_ulong prev_priv = get_field(mstatus, MSTATUS_MPP);
+    uintptr_t ra = GETPC();
 
-    check_ret_from_m_mode(env, retpc, prev_priv);
+    check_ret_from_m_mode(env, retpc, prev_priv, ra);
 
     target_ulong prev_virt = get_field(env->mstatus, MSTATUS_MPV) &&
                              (prev_priv != PRV_M);
@@ -443,8 +445,9 @@ target_ulong helper_mnret(CPURISCVState *env)
     target_ulong retpc = env->mnepc;
     target_ulong prev_priv = get_field(env->mnstatus, MNSTATUS_MNPP);
     target_ulong prev_virt;
+    uintptr_t ra = GETPC();
 
-    check_ret_from_m_mode(env, retpc, prev_priv);
+    check_ret_from_m_mode(env, retpc, prev_priv, ra);
 
     prev_virt = get_field(env->mnstatus, MNSTATUS_MNPV) &&
                 (prev_priv != PRV_M);