Re: [Qemu-devel] [PATCH] target-sparc: fix register corruption in ldstub if there is no write permission

[Artyom Tarasenko]

On Fri, Jun 24, 2016 at 5:51 PM, Mark Cave-Ayland
<address@hidden> wrote:
> On 24/06/16 13:34, Artyom Tarasenko wrote:
>
>> Signed-off-by: Artyom Tarasenko <address@hidden>
>> ---
>>  target-sparc/translate.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/target-sparc/translate.c b/target-sparc/translate.c
>> index 5111cf0..065326c 100644
>> --- a/target-sparc/translate.c
>> +++ b/target-sparc/translate.c
>> @@ -5187,12 +5187,15 @@ printf("ops, illegal rdhpr\n");
>>                  case 0xd:       /* ldstub -- XXX: should be atomically */
>>                      {
>>                          TCGv r_const;
>> +                        TCGv tmp = tcg_temp_new();
>>
>>                          gen_address_mask(dc, cpu_addr);
>> -                        tcg_gen_qemu_ld8u(cpu_val, cpu_addr,
>> dc->mem_idx);
>> +                        tcg_gen_qemu_ld8u(tmp, cpu_addr, dc->mem_idx);
>>                          r_const = tcg_const_tl(0xff);
>>                          tcg_gen_qemu_st8(r_const, cpu_addr, dc->mem_idx);
>> +                        tcg_gen_mov_tl(cpu_val, tmp);
>>                          tcg_temp_free(r_const);
>> +                        tcg_temp_free(tmp);
>>                      }
>>                      break;
>>                  case 0x0f:
>>
>
> Looks like you beat me to it - I can confirm that this fixes the issue here
> for me. Whilst testing I noticed another regression under qemu-system-sparc,
> however bisection reveals that this isn't caused by a SPARC-specific patch
> (and can be followed up separately) so:
>
> Tested-by: Mark Cave-Ayland <address@hidden>
>

Good. Then we can route it via your tree. (With Richard's Reviewed-by)
I'm still worried why it didn't hit us before.

Artyom

-- 
Regards,
Artyom Tarasenko

SPARC and PPC PReP under qemu blog: http://tyom.blogspot.com/search/label/qemu