Re: [Qemu-devel] [PATCH 00/10] Support the Capstone disassembler

[Richard Henderson <richard.henderson@linaro.org>]

On 09/19/2017 12:30 PM, Philippe Mathieu-Daudé wrote:
> On 09/19/2017 01:13 PM, Richard Henderson wrote:
>> [ Just saw this, so missed adding tags to the v2 patch set. ]
>>
>> On 09/14/2017 11:53 PM, Philippe Mathieu-Daudé wrote:
>>> At least this msg disappeared:
>>>
>>> "Disassembler disagrees with translator over instruction decoding"
>>
>> It's back in v2.
>>
>>> For i386, arm, mips32/64:
>>> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>>
>> Which patches?  Which mips versions?
> 
> full series, Malta board default cpu
> 
>> Can you, by any chance, test micro-mips?  I'm certain I've got that wrong in
>> the v1 patch, and thus I dropped the mips patch from v2.  But in theory
>> capstone supports umips too and should be trivially fixable.
> 
> $ mipsel-softmmu/qemu-system-mipsel -machine malta -cpu M14Kc -append "ttyS0
> rw" -nographic -d in_asm -kernel vmlinux -initrd initrd.gz
> 
>  IN: kernel_entry
>  0x801039e0:  syscall   0x3f004
>  0x801039e4:  b 0x8011406c
> -0x801039e8:  addu      t2,zero,ra
> -0x801039ec:  c0        0x900028
> -0x801039f0:  0x1f7108
> -0x801039f4:  syscall   0xbf004
> +0x801039e8:  addu         $t2, $zero, $ra

This is indicative of the other bug that I fixed in v2, where we would silently
ignore unknown instructions.

>From this and the other hunks it would appear that either (1) I messed up the
CS_MODE_* bits for mips or (2) the capstone backend for mips is not in terribly
good shape.

I think I was right to drop the patch from v2.


r~