diff mbox series

[v5,06/48] target/nios2: Fix BRET instruction

Message ID 20220310112725.570053-7-richard.henderson@linaro.org
State Superseded
Headers show
Series target/nios2: Shadow register set, EIC and VIC | expand

Commit Message

Richard Henderson March 10, 2022, 11:26 a.m. UTC 
We had failed to copy BSTATUS back to STATUS, and diagnose
supervisor-only.  The spec is light on the specifics of the
implementation of bret, but it is an easy assumption that
the restore into STATUS should work the same as eret.

Therefore, reuse the existing helper_eret.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/nios2/translate.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

Comments

Peter Maydell March 10, 2022, 12:17 p.m. UTC | #1 
On Thu, 10 Mar 2022 at 11:27, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> We had failed to copy BSTATUS back to STATUS, and diagnose
> supervisor-only.  The spec is light on the specifics of the
> implementation of bret, but it is an easy assumption that
> the restore into STATUS should work the same as eret.
>
> Therefore, reuse the existing helper_eret.
>
> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
diff mbox series

Patch

diff --git a/target/nios2/translate.c b/target/nios2/translate.c
index 7c2c430e99..3f7bbd6d7b 100644
--- a/target/nios2/translate.c
+++ b/target/nios2/translate.c
@@ -407,12 +407,22 @@  static void ret(DisasContext *dc, uint32_t code, uint32_t flags)
     dc->base.is_jmp = DISAS_JUMP;
 }
 
-/* PC <- ba */
+/*
+ * status <- bstatus
+ * PC <- ba
+ */
 static void bret(DisasContext *dc, uint32_t code, uint32_t flags)
 {
-    tcg_gen_mov_tl(cpu_pc, cpu_R[R_BA]);
+    if (!gen_check_supervisor(dc)) {
+        return;
+    }
 
-    dc->base.is_jmp = DISAS_JUMP;
+#ifdef CONFIG_USER_ONLY
+    g_assert_not_reached();
+#else
+    gen_helper_eret(cpu_env, cpu_R[CR_BSTATUS], cpu_R[R_BA]);
+    dc->base.is_jmp = DISAS_NORETURN;
+#endif
 }
 
 /* PC <- rA */