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| author | Quentin Casasnovas <quentin.casasnovas@oracle.com> | 2015-03-05 13:19:22 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-03-05 18:20:36 +0100 |
| commit | 06c8173eb92bbfc03a0fe8bb64315857d0badd06 (patch) | |
| tree | 73ecc10d3017c9ae7a6403fca3afbf3d7ec12997 /arch | |
| parent | 9ab6eb51ef4ad63cb71533d3a4dfb09ea8f69b4c (diff) | |
| download | linux-06c8173eb92bbfc03a0fe8bb64315857d0badd06.tar.bz2 | |
x86/fpu/xsaves: Fix improper uses of __ex_table
Commit:
f31a9f7c7169 ("x86/xsaves: Use xsaves/xrstors to save and restore xsave area")
introduced alternative instructions for XSAVES/XRSTORS and commit:
adb9d526e982 ("x86/xsaves: Add xsaves and xrstors support for booting time")
added support for the XSAVES/XRSTORS instructions at boot time.
Unfortunately both failed to properly protect them against faulting:
The 'xstate_fault' macro will use the closest label named '1'
backward and that ends up in the .altinstr_replacement section
rather than in .text. This means that the kernel will never find
in the __ex_table the .text address where this instruction might
fault, leading to serious problems if userspace manages to
trigger the fault.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Jamie Iles <jamie.iles@oracle.com>
[ Improved the changelog, fixed some whitespace noise. ]
Acked-by: Borislav Petkov <bp@alien8.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Cc: Allan Xavier <mr.a.xavier@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: adb9d526e982 ("x86/xsaves: Add xsaves and xrstors support for booting time")
Fixes: f31a9f7c7169 ("x86/xsaves: Use xsaves/xrstors to save and restore xsave area")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/xsave.h | 28 |
1 files changed, 11 insertions, 17 deletions
diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 5fa9770035dc..c9a6d68b8d62 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -82,18 +82,15 @@ static inline int xsave_state_booting(struct xsave_struct *fx, u64 mask) if (boot_cpu_has(X86_FEATURE_XSAVES)) asm volatile("1:"XSAVES"\n\t" "2:\n\t" - : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) + xstate_fault + : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); else asm volatile("1:"XSAVE"\n\t" "2:\n\t" - : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) + xstate_fault + : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); - - asm volatile(xstate_fault - : "0" (0) - : "memory"); - return err; } @@ -112,18 +109,15 @@ static inline int xrstor_state_booting(struct xsave_struct *fx, u64 mask) if (boot_cpu_has(X86_FEATURE_XSAVES)) asm volatile("1:"XRSTORS"\n\t" "2:\n\t" - : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) + xstate_fault + : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); else asm volatile("1:"XRSTOR"\n\t" "2:\n\t" - : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) + xstate_fault + : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); - - asm volatile(xstate_fault - : "0" (0) - : "memory"); - return err; } @@ -149,9 +143,9 @@ static inline int xsave_state(struct xsave_struct *fx, u64 mask) */ alternative_input_2( "1:"XSAVE, - "1:"XSAVEOPT, + XSAVEOPT, X86_FEATURE_XSAVEOPT, - "1:"XSAVES, + XSAVES, X86_FEATURE_XSAVES, [fx] "D" (fx), "a" (lmask), "d" (hmask) : "memory"); @@ -178,7 +172,7 @@ static inline int xrstor_state(struct xsave_struct *fx, u64 mask) */ alternative_input( "1: " XRSTOR, - "1: " XRSTORS, + XRSTORS, X86_FEATURE_XSAVES, "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); |