target/riscv/pmp: fix no pmp illegal intrs

As per the privilege specification, any access from S/U mode should fail
if no pmp region is configured and pmp is present, othwerwise access
should succeed.

Fixes: d102f19a208 (target/riscv/pmp: Raise exception if no PMP entry is configured)
Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20211214092659.15709-1-nikita.shubin@maquefel.me
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index ee7c24e..58d992e 100644 (file)
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -146,7 +146,8 @@ target_ulong helper_mret(CPURISCVState *env, target_ulong cpu_pc_deb)
     uint64_t mstatus = env->mstatus;
     target_ulong prev_priv = get_field(mstatus, MSTATUS_MPP);
 
-    if (!pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
+    if (riscv_feature(env, RISCV_FEATURE_PMP) &&
+        !pmp_get_num_rules(env) && (prev_priv != PRV_M)) {
         riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
     }