Commit e70b1008 authored Jan 09, 2020 by Yu-cheng Yu Committed by Borislav Petkov Feb 12, 2020

x86/fpu/xstate: Warn when checking alignment of disabled xfeatures



An XSAVES component's alignment/offset is meaningful only when the
feature is enabled. Return zero and WARN_ONCE on checking alignment of
disabled features.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20200109211452.27369-4-yu-cheng.yu@intel.com

parent 49a91d61

arch/x86/kernel/fpu/xstate.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -325,6 +325,13 @@ static int xfeature_is_aligned(int xfeature_nr)
		u32 eax, ebx, ecx, edx;

		CHECK_XFEATURE(xfeature_nr);

		if (!xfeature_enabled(xfeature_nr)) {
		WARN_ONCE(1, "Checking alignment of disabled xfeature %d\n",
		xfeature_nr);
		return 0;
		}

		cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
		/*
		* The value returned by ECX[1] indicates the alignment

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