Re: [PATCH] x86/fpu: move FPU state into separate cache

From: hpa
Date: Wed Mar 29 2017 - 18:45:32 EST


On March 29, 2017 2:41:00 PM PDT, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>On Wed, Mar 29, 2017 at 2:35 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx>
>wrote:
>>
>> Randomization also needs to leave thread_info at the beginning. Can
>it do that?
>
>Good point, and good question. No idea if the gcc extension can do,
>but yes, it clearly needs a "you can't move this entry".
>
>I assume it has some such capability already, because it's fairly
>common to have that kind of "beginning of structure if fixed" due to
>unions of structures anyway.
>
> Linus

An alternative is to wrap the randomized structure inside a nonrandomized wrapper structure.
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