tree 7ee8476ec114dbab907e3acf4e8a9d0342bf6751
parent b339a18b81a1f6ca1455559594f5df872b9e59f4
author Linus Torvalds <[EMAIL PROTECTED]> Sat, 23 Jul 2005 00:06:16 -0400
committer Linus Torvalds <[EMAIL PROTECTED]> Sat, 23 Jul 2005 00:06:16 -0400
x86: make restore_fpu() use alternative assembler instructions
It's really just a single instruction, conditional on whether the CPU
supports FXSR or not, so implement it as such instead of making it a
function that queries FXSR dynamically.
This means that the instruction just gets automatically rewritten to the
correct one at boot-time.
arch/i386/kernel/i387.c | 11 -----------
include/asm-i386/i387.h | 13 ++++++++++++-
2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/arch/i386/kernel/i387.c b/arch/i386/kernel/i387.c
--- a/arch/i386/kernel/i387.c
+++ b/arch/i386/kernel/i387.c
@@ -82,17 +82,6 @@ void kernel_fpu_begin(void)
}
EXPORT_SYMBOL_GPL(kernel_fpu_begin);
-void restore_fpu( struct task_struct *tsk )
-{
- if ( cpu_has_fxsr ) {
- asm volatile( "fxrstor %0"
- : : "m" (tsk->thread.i387.fxsave) );
- } else {
- asm volatile( "frstor %0"
- : : "m" (tsk->thread.i387.fsave) );
- }
-}
-
/*
* FPU tag word conversions.
*/
diff --git a/include/asm-i386/i387.h b/include/asm-i386/i387.h
--- a/include/asm-i386/i387.h
+++ b/include/asm-i386/i387.h
@@ -19,10 +19,21 @@
extern void mxcsr_feature_mask_init(void);
extern void init_fpu(struct task_struct *);
+
/*
* FPU lazy state save handling...
*/
-extern void restore_fpu( struct task_struct *tsk );
+
+/*
+ * The "nop" is needed to make the instructions the same
+ * length.
+ */
+#define restore_fpu(tsk) \
+ alternative_input( \
+ "nop ; frstor %1", \
+ "fxrstor %1", \
+ X86_FEATURE_FXSR, \
+ "m" ((tsk)->thread.i387.fsave))
extern void kernel_fpu_begin(void);
#define kernel_fpu_end() do { stts(); preempt_enable(); } while(0)
-
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