Re: [Qemu-devel] [PATCH 1/7] target/arm/translate-a64: Don't underdecode system instructions

[Laurent Desnogues]

On Fri, Jan 25, 2019 at 7:26 PM Peter Maydell  wrote:
>
> The "system instructions" and "system register move" subcategories
> of "branches, exception generating and system instructions" for A64
> only apply if bits [23:22] are zero; other values are currently
> unallocated. Correctly UNDEF these unallocated encodings.
>
> Reported-by: Laurent Desnogues 
> Signed-off-by: Peter Maydell 

Reviewed-by: Laurent Desnogues 

Thanks,

Laurent

> ---
>  target/arm/translate-a64.c | 6 +-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
> index 4d28a27c3bd..e6df303e321 100644
> --- a/target/arm/translate-a64.c
> +++ b/target/arm/translate-a64.c
> @@ -2144,7 +2144,11 @@ static void disas_b_exc_sys(DisasContext *s, uint32_t 
> insn)
>  break;
>  case 0x6a: /* Exception generation / System */
>  if (insn & (1 << 24)) {
> -disas_system(s, insn);
> +if (extract32(insn, 22, 2) == 0) {
> +disas_system(s, insn);
> +} else {
> +unallocated_encoding(s);
> +}
>  } else {
>  disas_exc(s, insn);
>  }
> --
> 2.20.1
>

[Qemu-devel] [PATCH 1/7] target/arm/translate-a64: Don't underdecode system instructions

[Peter Maydell]

The "system instructions" and "system register move" subcategories
of "branches, exception generating and system instructions" for A64
only apply if bits [23:22] are zero; other values are currently
unallocated. Correctly UNDEF these unallocated encodings.

Reported-by: Laurent Desnogues 
Signed-off-by: Peter Maydell 
---
 target/arm/translate-a64.c | 6 +-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 4d28a27c3bd..e6df303e321 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -2144,7 +2144,11 @@ static void disas_b_exc_sys(DisasContext *s, uint32_t 
insn)
 break;
 case 0x6a: /* Exception generation / System */
 if (insn & (1 << 24)) {
-disas_system(s, insn);
+if (extract32(insn, 22, 2) == 0) {
+disas_system(s, insn);
+} else {
+unallocated_encoding(s);
+}
 } else {
 disas_exc(s, insn);
 }
-- 
2.20.1