Re: [PATCH v13 8/9] Add 32 bit VDSO time support for 32 bit kernel

From: H. Peter Anvin
Date: Sun Feb 09 2014 - 15:12:51 EST


On 02/09/2014 03:45 AM, Stefani Seibold wrote:
>>
>> Yes the syscall does, but the vsyscall stub does not (for the !0x80 case)
>
> I cross check all kinds of vsyscall and all do save the ECX registers.
>
> So IMHO i see no register modification other than EAX, which is declared
> as the output register in the asm() directive.
>

That is, indeed, correct, as the 32-bit vsyscall stubs are explicitly
designed to be drop-in replacements for the int $0x80 instruction.

-hpa


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