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[v2,8/9] target/hppa: Avoid accessing %gr0 when raising exception

Message ID 20240107132237.50553-9-deller@kernel.org
State New
Headers show
Series target/hppa qemu v8.2 regression fixes | expand

Commit Message

Helge Deller Jan. 7, 2024, 1:22 p.m. UTC 
From: Helge Deller <deller@gmx.de>

The value of unwind_breg may reference register %r0, but we need to avoid
accessing gr0 directly and use the value 0 instead.

At runtime I've seen unwind_breg being zero with the Linux kernel when
rfi is used to jump to smp_callin().

Signed-off-by: Helge Deller <deller@gmx.de>
---
 target/hppa/mem_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Richard Henderson Jan. 9, 2024, 10:06 a.m. UTC | #1 
On 1/8/24 00:22, deller@kernel.org wrote:
> From: Helge Deller <deller@gmx.de>
> 
> The value of unwind_breg may reference register %r0, but we need to avoid
> accessing gr0 directly and use the value 0 instead.
> 
> At runtime I've seen unwind_breg being zero with the Linux kernel when
> rfi is used to jump to smp_callin().
> 
> Signed-off-by: Helge Deller <deller@gmx.de>
> ---
>   target/hppa/mem_helper.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/hppa/mem_helper.c b/target/hppa/mem_helper.c
> index 011b192406..42bd0063c0 100644
> --- a/target/hppa/mem_helper.c
> +++ b/target/hppa/mem_helper.c
> @@ -335,7 +335,7 @@ raise_exception_with_ior(CPUHPPAState *env, int excp, uintptr_t retaddr,
>   
>                   cpu_restore_state(cs, retaddr);
>   
> -                b = env->gr[env->unwind_breg];
> +                b = env->unwind_breg ? env->gr[env->unwind_breg] : 0;
>                   b >>= (env->psw & PSW_W ? 62 : 30);
>                   env->cr[CR_IOR] |= b << 62;
>   

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~
diff mbox series

Patch

diff --git a/target/hppa/mem_helper.c b/target/hppa/mem_helper.c
index 011b192406..42bd0063c0 100644
--- a/target/hppa/mem_helper.c
+++ b/target/hppa/mem_helper.c
@@ -335,7 +335,7 @@  raise_exception_with_ior(CPUHPPAState *env, int excp, uintptr_t retaddr,
 
                 cpu_restore_state(cs, retaddr);
 
-                b = env->gr[env->unwind_breg];
+                b = env->unwind_breg ? env->gr[env->unwind_breg] : 0;
                 b >>= (env->psw & PSW_W ? 62 : 30);
                 env->cr[CR_IOR] |= b << 62;