From b11ca7fbc735aca5ab78ce8130603bbf4fefd3f7 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 20 May 2015 09:59:30 +0200 Subject: [PATCH] x86/fpu/xstate: Use explicit parameter in xstate_fault() While looking at xstate.h it took me some time to realize that 'xstate_fault' uses 'err' as a silent parameter. This is not obvious at the call site, at all. Make it an explicit macro argument, so that the syntactic connection is easier to see. Also explain xstate_fault() a bit. Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/fpu/xstate.h | 34 ++++++++++++++++++------------- 1 file changed, 20 insertions(+), 14 deletions(-) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 8f336d2ae126..a6e07bb31526 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -47,12 +47,18 @@ extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask); #define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f" #define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f" -#define xstate_fault ".section .fixup,\"ax\"\n" \ - "3: movl $-1,%[err]\n" \ - " jmp 2b\n" \ - ".previous\n" \ - _ASM_EXTABLE(1b, 3b) \ - : [err] "=r" (err) +/* xstate instruction fault handler: */ +#define xstate_fault(__err) \ + \ + ".section .fixup,\"ax\"\n" \ + \ + "3: movl $-1,%[err]\n" \ + " jmp 2b\n" \ + \ + ".previous\n" \ + \ + _ASM_EXTABLE(1b, 3b) \ + : [err] "=r" (__err) /* * This function is called only during boot time when x86 caps are not set @@ -70,13 +76,13 @@ static inline int copy_xregs_to_kernel_booting(struct xregs_state *fx) if (boot_cpu_has(X86_FEATURE_XSAVES)) asm volatile("1:"XSAVES"\n\t" "2:\n\t" - xstate_fault + xstate_fault(err) : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); else asm volatile("1:"XSAVE"\n\t" "2:\n\t" - xstate_fault + xstate_fault(err) : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); return err; @@ -97,13 +103,13 @@ static inline int copy_kernel_to_xregs_booting(struct xregs_state *fx, u64 mask) if (boot_cpu_has(X86_FEATURE_XSAVES)) asm volatile("1:"XRSTORS"\n\t" "2:\n\t" - xstate_fault + xstate_fault(err) : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); else asm volatile("1:"XRSTOR"\n\t" "2:\n\t" - xstate_fault + xstate_fault(err) : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) : "memory"); return err; @@ -141,7 +147,7 @@ static inline int copy_xregs_to_kernel(struct xregs_state *fx) [fx] "D" (fx), "a" (lmask), "d" (hmask) : "memory"); asm volatile("2:\n\t" - xstate_fault + xstate_fault(err) : "0" (0) : "memory"); @@ -169,7 +175,7 @@ static inline int copy_kernel_to_xregs(struct xregs_state *fx, u64 mask) : "memory"); asm volatile("2:\n" - xstate_fault + xstate_fault(err) : "0" (0) : "memory"); @@ -201,7 +207,7 @@ static inline int copy_xregs_to_user(struct xregs_state __user *buf) __asm__ __volatile__(ASM_STAC "\n" "1:"XSAVE"\n" "2: " ASM_CLAC "\n" - xstate_fault + xstate_fault(err) : "D" (buf), "a" (-1), "d" (-1), "0" (0) : "memory"); return err; @@ -220,7 +226,7 @@ static inline int copy_user_to_xregs(struct xregs_state __user *buf, u64 mask) __asm__ __volatile__(ASM_STAC "\n" "1:"XRSTOR"\n" "2: " ASM_CLAC "\n" - xstate_fault + xstate_fault(err) : "D" (xstate), "a" (lmask), "d" (hmask), "0" (0) : "memory"); /* memory required? */ return err; -- 2.39.5