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/*
* include/asm-i386/i387.h
*
* Copyright (C) 1994 Linus Torvalds
*
* Pentium III FXSR, SSE support
* General FPU state handling cleanups
* Gareth Hughes <gareth@valinux.com>, May 2000
*/
#ifndef __ASM_I386_I387_H
#define __ASM_I386_I387_H
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <asm/processor.h>
#include <asm/sigcontext.h>
#include <asm/user.h>
extern void mxcsr_feature_mask_init(void);
extern void init_fpu(struct task_struct *);
/*
* FPU lazy state save handling...
*/
/*
* 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.fxsave))
extern void kernel_fpu_begin(void);
#define kernel_fpu_end() do { stts(); preempt_enable(); } while(0)
/* We need a safe address that is cheap to find and that is already
in L1 during context switch. The best choices are unfortunately
different for UP and SMP */
#ifdef CONFIG_SMP
#define safe_address (__per_cpu_offset[0])
#else
#define safe_address (kstat_cpu(0).cpustat.user)
#endif
/*
* These must be called with preempt disabled
*/
static inline void __save_init_fpu( struct task_struct *tsk )
{
/* 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" (tsk->thread.i387.fxsave),
[fsw] "m" (tsk->thread.i387.fxsave.swd) : "memory");
/* 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));
task_thread_info(tsk)->status &= ~TS_USEDFPU;
}
#define __unlazy_fpu( tsk ) do { \
if (task_thread_info(tsk)->status & TS_USEDFPU) \
save_init_fpu( tsk ); \
} while (0)
#define __clear_fpu( tsk ) \
do { \
if (task_thread_info(tsk)->status & TS_USEDFPU) { \
asm volatile("fnclex ; fwait"); \
task_thread_info(tsk)->status &= ~TS_USEDFPU; \
stts(); \
} \
} while (0)
/*
* These disable preemption on their own and are safe
*/
static inline void save_init_fpu( struct task_struct *tsk )
{
preempt_disable();
__save_init_fpu(tsk);
stts();
preempt_enable();
}
#define unlazy_fpu( tsk ) do { \
preempt_disable(); \
__unlazy_fpu(tsk); \
preempt_enable(); \
} while (0)
#define clear_fpu( tsk ) do { \
preempt_disable(); \
__clear_fpu( tsk ); \
preempt_enable(); \
} while (0)
\
/*
* FPU state interaction...
*/
extern unsigned short get_fpu_cwd( struct task_struct *tsk );
extern unsigned short get_fpu_swd( struct task_struct *tsk );
extern unsigned short get_fpu_mxcsr( struct task_struct *tsk );
/*
* Signal frame handlers...
*/
extern int save_i387( struct _fpstate __user *buf );
extern int restore_i387( struct _fpstate __user *buf );
/*
* ptrace request handers...
*/
extern int get_fpregs( struct user_i387_struct __user *buf,
struct task_struct *tsk );
extern int set_fpregs( struct task_struct *tsk,
struct user_i387_struct __user *buf );
extern int get_fpxregs( struct user_fxsr_struct __user *buf,
struct task_struct *tsk );
extern int set_fpxregs( struct task_struct *tsk,
struct user_fxsr_struct __user *buf );
/*
* FPU state for core dumps...
*/
extern int dump_fpu( struct pt_regs *regs,
struct user_i387_struct *fpu );
#endif /* __ASM_I386_I387_H */
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