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Commit f9de314b authored by Fenghua Yu's avatar Fenghua Yu Committed by H. Peter Anvin
Browse files

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: default avatarFenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1401387164-43416-10-git-send-email-fenghua.yu@intel.com


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent f31a9f7c

arch/x86/include/asm/xsave.h

+12 −25
Original line number Diff line number Diff line
@@ -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