On July 27, 2020 1:36:19 AM PDT, pet...@infradead.org wrote:
>On Sun, Jul 26, 2020 at 10:55:15PM -0700, h...@zytor.com wrote:
>> For a really overenginered solution, but which might perform
>> unnecessary poorly on existing hardware:
>>
>> asm volatile("1: .byte 0xf, 0x1, 0xe8; 2:"
>> _ASM_EXTABLE(1b,2b));
>
>Ha! cute, you take an #UD ?
>
>We could optimize the #UD exception handler for this I suppose, but
>that
>makes it an even worse hack. The simple alternative() seems like a much
>simpler approach.
If this is in any way performance critical, then no :) Taking the #UD has the
cute property that we end up IRET on the way back, so we don't even need a
fix-up path.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
