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Commit f31a9f7c authored by Fenghua Yu's avatar Fenghua Yu Committed by H. Peter Anvin
Browse files

x86/xsaves: Use xsaves/xrstors to save and restore xsave area 



If xsaves is eanbled, use xsaves/xrstors instrucitons to save and restore
xstate. xsaves and xrstors support compacted format, init optimization,
modified optimization, and supervisor states.

Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1401387164-43416-9-git-send-email-fenghua.yu@intel.com


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent b84e7055

arch/x86/include/asm/xsave.h

+64 −20
Original line number Diff line number Diff line
@@ -65,6 +65,70 @@ extern int init_fpu(struct task_struct *child); 
			_ASM_EXTABLE(1b, 3b)		\

			: [err] "=r" (err)



/*

 * Save processor xstate to xsave area.

 */

static inline int xsave_state(struct xsave_struct *fx, u64 mask)

{

	u32 lmask = mask;

	u32 hmask = mask >> 32;

	int err = 0;



	/*

	 * If xsaves is enabled, xsaves replaces xsaveopt because

	 * it supports compact format and supervisor states in addition to

	 * modified optimization in xsaveopt.

	 *

	 * Otherwise, if xsaveopt is enabled, xsaveopt replaces xsave

	 * because xsaveopt supports modified optimization which is not

	 * supported by xsave.

	 *

	 * If none of xsaves and xsaveopt is enabled, use xsave.

	 */

	alternative_input_2(

		"1:"XSAVE,

		"1:"XSAVEOPT,

		X86_FEATURE_XSAVEOPT,

		"1:"XSAVES,

		X86_FEATURE_XSAVES,

		[fx] "D" (fx), "a" (lmask), "d" (hmask) :

		"memory");

	asm volatile("2:\n\t"

		     xstate_fault

		     : "0" (0)

		     : "memory");



	return err;

}



/*

 * Restore processor xstate from xsave area.

 */

static inline int xrstor_state(struct xsave_struct *fx, u64 mask)

{

	int err = 0;

	u32 lmask = mask;

	u32 hmask = mask >> 32;



	/*

	 * Use xrstors to restore context if it is enabled. xrstors supports

	 * compacted format of xsave area which is not supported by xrstor.

	 */

	alternative_input(

		"1: " XRSTOR,

		"1: " XRSTORS,

		X86_FEATURE_XSAVES,

		"D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)

		: "memory");



	asm volatile("2:\n"

		     xstate_fault

		     : "0" (0)

		     : "memory");



	return err;

}



static inline int fpu_xrstor_checking(struct xsave_struct *fx)

{

	int err;
@@ -130,26 +194,6 @@ static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask) 
	return err;

}



static inline void xrstor_state(struct xsave_struct *fx, u64 mask)

{

	u32 lmask = mask;

	u32 hmask = mask >> 32;



	asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"

		     : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)

		     :   "memory");

}



static inline void xsave_state(struct xsave_struct *fx, u64 mask)

{

	u32 lmask = mask;

	u32 hmask = mask >> 32;



	asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t"

		     : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)

		     :   "memory");

}



static inline void fpu_xsave(struct fpu *fpu)

{

	/* This, however, we can work around by forcing the compiler to select