Commit-ID: f31a9f7c71691569359fa7fb8b0acaa44bce0324
Gitweb: http://git.kernel.org/tip/f31a9f7c71691569359fa7fb8b0acaa44bce0324
Author: Fenghua Yu <fenghua.yu@xxxxxxxxx>
AuthorDate: Thu, 29 May 2014 11:12:36 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Thu, 29 May 2014 14:31:21 -0700
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@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1401387164-43416-9-git-send-email-fenghua.yu@xxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/xsave.h | 84 +++++++++++++++++++++++++++++++++-----------
1 file changed, 64 insertions(+), 20 deletions(-)
diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index 76c2459..f9177a2 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -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
--
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