Re: [PATCH 02/19] x86, fpu: Wrap get_xsave_addr() to make it safer

From: Dave Hansen
Date: Thu May 28 2015 - 10:45:31 EST


On 05/28/2015 01:41 AM, Ingo Molnar wrote:
> What you want here is to make the (in-memory) FPU state valid and current, before
> reading it, and the function to use for that is fpu__activate_fpstate_read()
> (available in the latest tip:x86/fpu tree).

Do we really want to unconditionally activate the FPU?

Let's say supporting MPX didn't require eager mode and someone called
get_xsave_addr(). We would ideally want to keep the FPU inactive and
just return NULL. Right?
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