Commit-ID: 06c8173eb92bbfc03a0fe8bb64315857d0badd06 Gitweb: http://git.kernel.org/tip/06c8173eb92bbfc03a0fe8bb64315857d0badd06 Author: Quentin Casasnovas <quentin.casasnovas@xxxxxxxxxx> AuthorDate: Thu, 5 Mar 2015 13:19:22 +0100 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Thu, 5 Mar 2015 18:20:36 +0100 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@xxxxxxxxxx> Signed-off-by: Jamie Iles <jamie.iles@xxxxxxxxxx> [ Improved the changelog, fixed some whitespace noise. ] Acked-by: Borislav Petkov <bp@xxxxxxxxx> Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Cc: Allan Xavier <mr.a.xavier@xxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> 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@xxxxxxxxxx> --- arch/x86/include/asm/xsave.h | 28 +++++++++++----------------- 1 file changed, 11 insertions(+), 17 deletions(-) diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 5fa9770..c9a6d68 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"); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html