Hi, Richard.
On 09/10/2021 08:52 PM, Richard Henderson wrote:
> On 9/8/21 11:50 AM, Song Gao wrote:
>>
>> Hi Richard,
>>
>> On 09/05/2021 06:04 PM, Richard Henderson wrote:
>>>> +struct sigframe {
>>>> + uint32_t sf_ass[4]; /* argument save space for o32 */
>>>
>>> Surely there is no "o32" for loongarch?
>>>
>>
>> Yes, qemu only support 64bit. but the kernel has 'o32'. Should we have to
>> be consistent with the kernel?
>
> Yes, you need to be consistent with the kernel. However... the kernel is not
> yet upstream, and therefore the ABI is (officially) still malleable.
>
> Anyway, this padding was copied from mips o32, and should not have been.
> Looking at the loongarch gcc sources, REG_PARM_STACK_SPACE is always 0, and
> thus the 4 words reserved here are never used.
>
> I see that gcc/libgcc/config/loongarch/linux-unwind.h builds in knowledge of
> these unused words. I also see that linux/arch/loongarch/vdso/sigreturn.S
> does not provide correct unwind info. Certainly the kernel vdso should be
> fixed, so that code within gcc should not be needed. At which point the ABI
> for the signal frame is entirely private to the kernel.
>
We are cleanning up 'o32' code for gcc and kernel.
By the way, We have already prepared V5 patches. but I see that patches [1] and
[2] have not push into master. How can I use these patches?
[1]:
https://patchew.org/QEMU/[email protected]/
[2]:
https://patchew.org/QEMU/[email protected]/
Song Gao
thanks
>
> r~
