Messages in this thread | | | Subject | Re: [PATCH 1/2] x86/fpu: Reset MXCSR to default in kernel_fpu_begin() | From | Dave Hansen <> | Date | Mon, 22 Jun 2020 11:38:04 -0700 |
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On 6/22/20 11:33 AM, Andy Lutomirski wrote: > Suppose you do: > > double x = 1.0; > > kernel_fpu_begin(); > > x += 2.0; > > We want to make sure that GCC puts things in the right order. I > suppose that even a memory clobber is insufficient here, though.
Even with CONFIG_PREEMPT disabled, we still have:
#define preempt_disable() barrier()
I don't see us supporting preemptible kernel_fpu regions any time soon, so shouldn't this be sufficient now and for a long time?
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