V6: [PATCH] x86: Install <sys/platform/x86.h> [BZ #26124]
Mon Jun 29 16:49:24 GMT 2020
* H. J. Lu:
>> One thing I still dislike (sorry) is the asymmetry between the usable
>> and feature checks. For example, why is there are usability check for
>> VAES, but not for AES? I believe the reason is that VAES depends on
>> AVX/AVX2, but AES only depends on SSE2. But even that suggests to me
>> that for 32-bit, there should be a usable gate for that (which is false
>> if SSE2 support has been masked).
> CPU with AES must have SSE2. I don't think we need explicit check
> for SSE2.
But SSE2 needs operating system support, so we get the usable vs
available distinction this way. I think.
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