[Qemu-devel] [PATCH v8 18/35] RISC-V: Clear mtval/stval on exceptions without info

[Michael Clark]

mtval/stval must be set on all exceptions but zero is
a legal value if there is no exception specific info.
Placing the instruction bytes for illegal instruction
exceptions in mtval/stval is an optional feature and
is currently not supported by QEMU RISC-V.

Cc: Sagar Karandikar <address@hidden>
Cc: Bastian Koppelmann <address@hidden>
Cc: Palmer Dabbelt <address@hidden>
Cc: Alistair Francis <address@hidden>
Signed-off-by: Michael Clark <address@hidden>
---
 target/riscv/helper.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/target/riscv/helper.c b/target/riscv/helper.c
index 459fc97..3b57e13 100644
--- a/target/riscv/helper.c
+++ b/target/riscv/helper.c
@@ -492,6 +492,10 @@ void riscv_cpu_do_interrupt(CPUState *cs)
                     ": badaddr 0x" TARGET_FMT_lx, env->mhartid, env->badaddr);
             }
             env->sbadaddr = env->badaddr;
+        } else {
+            /* otherwise we must clear sbadaddr/stval
+             * todo: support populating stval on illegal instructions */
+            env->sbadaddr = 0;
         }
 
         target_ulong s = env->mstatus;
@@ -513,6 +517,10 @@ void riscv_cpu_do_interrupt(CPUState *cs)
                     ": badaddr 0x" TARGET_FMT_lx, env->mhartid, env->badaddr);
             }
             env->mbadaddr = env->badaddr;
+        } else {
+            /* otherwise we must clear mbadaddr/mtval
+             * todo: support populating mtval on illegal instructions */
+            env->mbadaddr = 0;
         }
 
         target_ulong s = env->mstatus;
-- 
2.7.0