x86/xsaves: Use xsaves/xrstors for context switch

If xsaves is eanbled, use xsaves/xrstors for context switch to support
compacted format xsave area to occupy less memory and modified optimization
to improve saving performance.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1401387164-43416-10-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 12 insertions, 25 deletions

diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index f9177a2a97e9..8b75824e41dd 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -129,22 +129,20 @@ static inline int xrstor_state(struct xsave_struct *fx, u64 mask)
         return err;
 }
 
-static inline int fpu_xrstor_checking(struct xsave_struct *fx)
+/*
+ * Save xstate context for old process during context switch.
+ */
+static inline void fpu_xsave(struct fpu *fpu)
 {
-        int err;
-
-        asm volatile("1: .byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
-                     "2:\n"
-                     ".section .fixup,\"ax\"\n"
-                     "3:  movl $-1,%[err]\n"
-                     "    jmp  2b\n"
-                     ".previous\n"
-                     _ASM_EXTABLE(1b, 3b)
-                     : [err] "=r" (err)
-                     : "D" (fx), "m" (*fx), "a" (-1), "d" (-1), "0" (0)
-                     : "memory");
+        xsave_state(&fpu->state->xsave, -1);
+}
 
-        return err;
+/*
+ * Restore xstate context for new process during context switch.
+ */
+static inline int fpu_xrstor_checking(struct xsave_struct *fx)
+{
+        return xrstor_state(fx, -1);
 }
 
 static inline int xsave_user(struct xsave_struct __user *buf)
@@ -194,15 +192,4 @@ static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask)
         return err;
 }
 
-static inline void fpu_xsave(struct fpu *fpu)
-{
-        /* This, however, we can work around by forcing the compiler to select
-           an addressing mode that doesn't require extended registers. */
-        alternative_input(
-                ".byte " REX_PREFIX "0x0f,0xae,0x27",
-                ".byte " REX_PREFIX "0x0f,0xae,0x37",
-                X86_FEATURE_XSAVEOPT,
-                [fx] "D" (&fpu->state->xsave), "a" (-1), "d" (-1) :
-                "memory");
-}
 #endif