Re: [PATCH] x86/uaccess: fix code generation in put_user()

[hpa]

On October 23, 2020 1:55:22 PM PDT, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>Thanks, applied.
>
>On Fri, Oct 23, 2020 at 1:32 PM Rasmus Villemoes
><linux@xxxxxxxxxxxxxxxxxx> wrote:
>>
>> I'm wondering if one would also need to make __ptr_pu and __ret_pu
>> explicitly "%"_ASM_CX".
>
>No, the "c"/"0" thing is much better, and makes it properly atomic wrt
>the actual asm.
>
>As mentioned to Andy, the "register asm()" thing is not uncommon and
>often useful, but when you can specify the register directly in asm,
>that's certainly simpler and more straightforward and preferred.
>
>              Linus

There is no same reason to mess around with hacks when we are talking about dx:ax, though. We have to do pretty ugly hacks when other register pairs are involved, but "A" is there for a reason. _ASM_AX64 maybe...
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