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

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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: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1401387164-43416-9-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Fenghua Yu 2014-05-29 11:12:36 -07:00 committed by H. Peter Anvin
parent b84e70552e
commit f31a9f7c71
1 changed files with 64 additions and 20 deletions
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84
arch/x86/include/asm/xsave.h
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@ -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