mirror of
https://github.com/torvalds/linux
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2847e3478c
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.
125 lines
2.8 KiB
C
125 lines
2.8 KiB
C
/*
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* include/asm-i386/i387.h
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*
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* Copyright (C) 1994 Linus Torvalds
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*
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* Pentium III FXSR, SSE support
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* General FPU state handling cleanups
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*/
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#ifndef __ASM_I386_I387_H
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#define __ASM_I386_I387_H
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <asm/processor.h>
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#include <asm/sigcontext.h>
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#include <asm/user.h>
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extern void mxcsr_feature_mask_init(void);
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extern void init_fpu(struct task_struct *);
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/*
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* FPU lazy state save handling...
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*/
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/*
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* The "nop" is needed to make the instructions the same
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* length.
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*/
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#define restore_fpu(tsk) \
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alternative_input( \
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"nop ; frstor %1", \
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"fxrstor %1", \
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X86_FEATURE_FXSR, \
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"m" ((tsk)->thread.i387.fxsave))
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extern void kernel_fpu_begin(void);
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#define kernel_fpu_end() do { stts(); preempt_enable(); } while(0)
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/*
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* These must be called with preempt disabled
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*/
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static inline void __save_init_fpu( struct task_struct *tsk )
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{
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alternative_input(
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"fnsave %1 ; fwait ;" GENERIC_NOP2,
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"fxsave %1 ; fnclex",
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X86_FEATURE_FXSR,
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"m" (tsk->thread.i387.fxsave)
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:"memory");
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tsk->thread_info->status &= ~TS_USEDFPU;
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}
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#define __unlazy_fpu( tsk ) do { \
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if ((tsk)->thread_info->status & TS_USEDFPU) \
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save_init_fpu( tsk ); \
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} while (0)
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#define __clear_fpu( tsk ) \
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do { \
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if ((tsk)->thread_info->status & TS_USEDFPU) { \
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asm volatile("fnclex ; fwait"); \
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(tsk)->thread_info->status &= ~TS_USEDFPU; \
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stts(); \
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} \
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} while (0)
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/*
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* These disable preemption on their own and are safe
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*/
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static inline void save_init_fpu( struct task_struct *tsk )
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{
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preempt_disable();
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__save_init_fpu(tsk);
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stts();
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preempt_enable();
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}
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#define unlazy_fpu( tsk ) do { \
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preempt_disable(); \
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__unlazy_fpu(tsk); \
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preempt_enable(); \
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} while (0)
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#define clear_fpu( tsk ) do { \
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preempt_disable(); \
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__clear_fpu( tsk ); \
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preempt_enable(); \
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} while (0)
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\
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/*
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* FPU state interaction...
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*/
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extern unsigned short get_fpu_cwd( struct task_struct *tsk );
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extern unsigned short get_fpu_swd( struct task_struct *tsk );
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extern unsigned short get_fpu_mxcsr( struct task_struct *tsk );
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/*
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* Signal frame handlers...
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*/
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extern int save_i387( struct _fpstate __user *buf );
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extern int restore_i387( struct _fpstate __user *buf );
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/*
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* ptrace request handers...
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*/
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extern int get_fpregs( struct user_i387_struct __user *buf,
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struct task_struct *tsk );
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extern int set_fpregs( struct task_struct *tsk,
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struct user_i387_struct __user *buf );
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extern int get_fpxregs( struct user_fxsr_struct __user *buf,
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struct task_struct *tsk );
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extern int set_fpxregs( struct task_struct *tsk,
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struct user_fxsr_struct __user *buf );
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/*
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* FPU state for core dumps...
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*/
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extern int dump_fpu( struct pt_regs *regs,
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struct user_i387_struct *fpu );
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#endif /* __ASM_I386_I387_H */
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