Messages in this thread | | | From | Andy Lutomirski <> | Date | Fri, 19 Jun 2020 11:01:44 -0700 | Subject | Re: [PATCH 1/2] x86/fpu: Reset MXCSR to default in kernel_fpu_begin() |
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On Fri, Jun 19, 2020 at 10:41 AM Borislav Petkov <bp@alien8.de> wrote: > > From: Petteri Aimonen <jpa@git.mail.kapsi.fi> > > Previously, kernel floating point code would run with the MXCSR control > register value last set by userland code by the thread that was active > on the CPU core just before kernel call. This could affect calculation > results if rounding mode was changed, or a crash if a FPU/SIMD exception > was unmasked. > > Restore MXCSR to the kernel's default value. > > [ bp: Carve out from a bigger patch by Petteri, add feature check, add > FNINIT call too (amluto). ]
Acked-by: Andy Lutomirski <luto@kernel.org>
but:
shouldn't kernel_fpu_begin() end with a barrier()?
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