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Subject[PATCH 1/3] x86: Split fpu_save_init() to fpu_save() and fpu_clear()
Date
fpu_save() would be used later by KVM.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
arch/x86/include/asm/i387.h | 71 ++++++++++++++++++++++++++-----------------
1 files changed, 43 insertions(+), 28 deletions(-)

diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 1a8cca3..989d3b7 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -180,13 +180,17 @@ static inline void fpu_fxsave(struct fpu *fpu)
#endif
}

-static inline void fpu_save_init(struct fpu *fpu)
+static inline void fpu_save(struct fpu *fpu)
{
if (use_xsave())
fpu_xsave(fpu);
else
fpu_fxsave(fpu);
+}

+static inline void fpu_save_init(struct fpu *fpu)
+{
+ fpu_save(fpu);
fpu_clear(fpu);
}

@@ -237,19 +241,41 @@ static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
/*
* These must be called with preempt disabled
*/
-static inline void fpu_save_init(struct fpu *fpu)
+static inline void fpu_fxsave(struct fpu *fpu)
{
- if (use_xsave()) {
- struct xsave_struct *xstate = &fpu->state->xsave;
- struct i387_fxsave_struct *fx = &fpu->state->fxsave;
+ /* Use more nops than strictly needed in case the compiler
+ varies code */
+ alternative_input(
+ "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4,
+ "fxsave %[fx]\n"
+ "bt $7,%[fsw] ; jnc 1f ; fnclex\n1:",
+ X86_FEATURE_FXSR,
+ [fx] "m" (fpu->state->fxsave),
+ [fsw] "m" (fpu->state->fxsave.swd) : "memory");
+}

+static inline void fpu_save(struct fpu *fpu)
+{
+ if (use_xsave())
fpu_xsave(fpu);
+ else
+ fpu_fxsave(fpu);
+}
+
+/* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
+ is pending. Clear the x87 state here by setting it to fixed
+ values. safe_address is a random variable that should be in L1 */
+static inline void fpu_clear(struct fpu *fpu)
+{
+ struct xsave_struct *xstate = &fpu->state->xsave;
+ struct i387_fxsave_struct *fx = &fpu->state->fxsave;

+ if (use_xsave()) {
/*
* xsave header may indicate the init state of the FP.
*/
if (!(xstate->xsave_hdr.xstate_bv & XSTATE_FP))
- goto end;
+ return;

if (unlikely(fx->swd & X87_FSW_ES))
asm volatile("fnclex");
@@ -257,30 +283,19 @@ static inline void fpu_save_init(struct fpu *fpu)
/*
* we can do a simple return here or be paranoid :)
*/
- goto clear_state;
}
+ alternative_input(
+ GENERIC_NOP8 GENERIC_NOP2,
+ "emms\n\t" /* clear stack tags */
+ "fildl %[addr]", /* set F?P to defined value */
+ X86_FEATURE_FXSAVE_LEAK,
+ [addr] "m" (safe_address));
+}

- /* Use more nops than strictly needed in case the compiler
- varies code */
- alternative_input(
- "fnsave %[fx] ;fwait;" GENERIC_NOP8 GENERIC_NOP4,
- "fxsave %[fx]\n"
- "bt $7,%[fsw] ; jnc 1f ; fnclex\n1:",
- X86_FEATURE_FXSR,
- [fx] "m" (fpu->state->fxsave),
- [fsw] "m" (fpu->state->fxsave.swd) : "memory");
-clear_state:
- /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
- is pending. Clear the x87 state here by setting it to fixed
- values. safe_address is a random variable that should be in L1 */
- alternative_input(
- GENERIC_NOP8 GENERIC_NOP2,
- "emms\n\t" /* clear stack tags */
- "fildl %[addr]", /* set F?P to defined value */
- X86_FEATURE_FXSAVE_LEAK,
- [addr] "m" (safe_address));
-end:
- ;
+static inline void fpu_save_init(struct fpu *fpu)
+{
+ fpu_save(fpu);
+ fpu_clear(fpu);
}

static inline void __save_init_fpu(struct task_struct *tsk)
--
1.7.0.1


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