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: 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>
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@ -65,6 +65,70 @@ extern int init_fpu(struct task_struct *child);
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_ASM_EXTABLE(1b, 3b) \
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: [err] "=r" (err)
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/*
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* Save processor xstate to xsave area.
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*/
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static inline int xsave_state(struct xsave_struct *fx, u64 mask)
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{
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u32 lmask = mask;
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u32 hmask = mask >> 32;
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int err = 0;
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/*
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* If xsaves is enabled, xsaves replaces xsaveopt because
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* it supports compact format and supervisor states in addition to
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* modified optimization in xsaveopt.
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*
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* Otherwise, if xsaveopt is enabled, xsaveopt replaces xsave
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* because xsaveopt supports modified optimization which is not
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* supported by xsave.
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*
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* If none of xsaves and xsaveopt is enabled, use xsave.
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*/
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alternative_input_2(
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"1:"XSAVE,
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"1:"XSAVEOPT,
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X86_FEATURE_XSAVEOPT,
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"1:"XSAVES,
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X86_FEATURE_XSAVES,
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[fx] "D" (fx), "a" (lmask), "d" (hmask) :
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"memory");
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asm volatile("2:\n\t"
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xstate_fault
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: "0" (0)
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: "memory");
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return err;
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}
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/*
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* Restore processor xstate from xsave area.
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*/
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static inline int xrstor_state(struct xsave_struct *fx, u64 mask)
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{
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int err = 0;
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u32 lmask = mask;
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u32 hmask = mask >> 32;
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/*
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* Use xrstors to restore context if it is enabled. xrstors supports
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* compacted format of xsave area which is not supported by xrstor.
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*/
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alternative_input(
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"1: " XRSTOR,
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"1: " XRSTORS,
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X86_FEATURE_XSAVES,
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"D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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asm volatile("2:\n"
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xstate_fault
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: "0" (0)
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: "memory");
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return err;
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}
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static inline int fpu_xrstor_checking(struct xsave_struct *fx)
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{
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int err;
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@ -130,26 +194,6 @@ static inline int xrestore_user(struct xsave_struct __user *buf, u64 mask)
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return err;
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}
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static inline void xrstor_state(struct xsave_struct *fx, u64 mask)
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{
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u32 lmask = mask;
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u32 hmask = mask >> 32;
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asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x2f\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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}
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static inline void xsave_state(struct xsave_struct *fx, u64 mask)
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{
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u32 lmask = mask;
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u32 hmask = mask >> 32;
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asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t"
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: : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask)
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: "memory");
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}
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static inline void fpu_xsave(struct fpu *fpu)
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{
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/* This, however, we can work around by forcing the compiler to select
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