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Commit 2847e347 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

x86: use alternative instructions for fnsave/fxsave too 

This one ends up using an inline asm format that claims to read memory
and then clobber it (rather than just write it directly), which made it
easier to use the existing "alternative_input()" infrastructure support.

Now the fxsave code matches the fxrstor.
parent 38afd6ad

include/asm-i386/i387.h

+7 −8
Original line number Original line Diff line number Diff line
@@ -33,7 +33,7 @@ extern void init_fpu(struct task_struct *); 
		"nop ; frstor %1",		\

		"nop ; frstor %1",		\

		"fxrstor %1",			\

		"fxrstor %1",			\

		X86_FEATURE_FXSR,		\

		X86_FEATURE_FXSR,		\

		"m" ((tsk)->thread.i387.fsave))

		"m" ((tsk)->thread.i387.fxsave))





extern void kernel_fpu_begin(void);

extern void kernel_fpu_begin(void);

#define kernel_fpu_end() do { stts(); preempt_enable(); } while(0)

#define kernel_fpu_end() do { stts(); preempt_enable(); } while(0)
@@ -43,13 +43,12 @@ extern void kernel_fpu_begin(void); 
 */

 */

static inline void __save_init_fpu( struct task_struct *tsk )

static inline void __save_init_fpu( struct task_struct *tsk )

{

{

	if ( cpu_has_fxsr ) {

	alternative_input(

		asm volatile( "fxsave %0 ; fnclex"

		"fnsave %1 ; fwait ;" GENERIC_NOP2,

			      : "=m" (tsk->thread.i387.fxsave) );

		"fxsave %1 ; fnclex",

	} else {

		X86_FEATURE_FXSR,

		asm volatile( "fnsave %0 ; fwait"

		"m" (tsk->thread.i387.fxsave)

			      : "=m" (tsk->thread.i387.fsave) );

		:"memory");

	}

	tsk->thread_info->status &= ~TS_USEDFPU;

	tsk->thread_info->status &= ~TS_USEDFPU;

}

}