x86/cpufeatures: Make X86_BUG_FXSAVE_LEAK detectable in CPUID on AMD

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The latest AMD AMD64 Architecture Programmer's Manual
adds a CPUID feature XSaveErPtr (CPUID_Fn80000008_EBX[2]).

If this feature is set, the FXSAVE, XSAVE, FXSAVEOPT, XSAVEC, XSAVES
/ FXRSTOR, XRSTOR, XRSTORS always save/restore error pointers,
thus making the X86_BUG_FXSAVE_LEAK workaround obsolete on such CPUs.

Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/bdcebe90-62c5-1f05-083c-eba7f08b2540@assembler.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Rudolf Marek 2017-11-28 22:01:06 +01:00 • committed by Ingo Molnar

parent 55d2d0ad2f

commit e3811a3f74

2 changed files with 6 additions and 2 deletions

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1

arch/x86/include/asm/cpufeatures.h

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7

arch/x86/kernel/cpu/amd.c

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