LXR linux/include/asm-x86

   1/*
   2 * include/asm-x86_64/i387.h
   3 *
   4 * Copyright (C) 1994 Linus Torvalds
   5 *
   6 * Pentium III FXSR, SSE support
   7 * General FPU state handling cleanups
   8 *      Gareth Hughes <gareth@valinux.com>, May 2000
   9 * x86-64 work by Andi Kleen 2002
  10 */
  11
  12#ifndef __ASM_X86_64_I387_H
  13#define __ASM_X86_64_I387_H
  14
  15#include <linux/sched.h>
  16#include <asm/processor.h>
  17#include <asm/sigcontext.h>
  18#include <asm/user.h>
  19#include <asm/thread_info.h>
  20#include <asm/uaccess.h>
  21
  22extern void fpu_init(void);
  23extern unsigned int mxcsr_feature_mask;
  24extern void mxcsr_feature_mask_init(void);
  25extern void init_fpu(struct task_struct *child);
  26extern int save_i387(struct _fpstate __user *buf);
  27
  28/*
  29 * FPU lazy state save handling...
  30 */
  31
  32#define unlazy_fpu(tsk) do { \
  33        if ((tsk)->thread_info->status & TS_USEDFPU) \
  34                save_init_fpu(tsk); \
  35} while (0)
  36
  37/* Ignore delayed exceptions from user space */
  38static inline void tolerant_fwait(void)
  39{
  40        asm volatile("1: fwait\n"
  41                     "2:\n"
  42                     "   .section __ex_table,\"a\"\n"
  43                     "  .align 8\n"
  44                     "  .quad 1b,2b\n"
  45                     "  .previous\n");
  46}
  47
  48#define clear_fpu(tsk) do { \
  49        if ((tsk)->thread_info->status & TS_USEDFPU) {          \
  50                tolerant_fwait();                               \
  51                (tsk)->thread_info->status &= ~TS_USEDFPU;      \
  52                stts();                                         \
  53        }                                                       \
  54} while (0)
  55
  56/*
  57 * ptrace request handers...
  58 */
  59extern int get_fpregs(struct user_i387_struct __user *buf,
  60                      struct task_struct *tsk);
  61extern int set_fpregs(struct task_struct *tsk,
  62                      struct user_i387_struct __user *buf);
  63
  64/*
  65 * i387 state interaction
  66 */
  67#define get_fpu_mxcsr(t) ((t)->thread.i387.fxsave.mxcsr)
  68#define get_fpu_cwd(t) ((t)->thread.i387.fxsave.cwd)
  69#define get_fpu_fxsr_twd(t) ((t)->thread.i387.fxsave.twd)
  70#define get_fpu_swd(t) ((t)->thread.i387.fxsave.swd)
  71#define set_fpu_cwd(t,val) ((t)->thread.i387.fxsave.cwd = (val))
  72#define set_fpu_swd(t,val) ((t)->thread.i387.fxsave.swd = (val))
  73#define set_fpu_fxsr_twd(t,val) ((t)->thread.i387.fxsave.twd = (val))
  74
  75static inline int restore_fpu_checking(struct i387_fxsave_struct *fx) 
  76{ 
  77        int err;
  78        asm volatile("1:  rex64 ; fxrstor (%[fx])\n\t"
  79                     "2:\n"
  80                     ".section .fixup,\"ax\"\n"
  81                     "3:  movl $-1,%[err]\n"
  82                     "    jmp  2b\n"
  83                     ".previous\n"
  84                     ".section __ex_table,\"a\"\n"
  85                     "   .align 8\n"
  86                     "   .quad  1b,3b\n"
  87                     ".previous"
  88                     : [err] "=r" (err)
  89                     : [fx] "r" (fx), "0" (0)); 
  90        if (unlikely(err))
  91                init_fpu(current);
  92        return err;
  93} 
  94
  95static inline int save_i387_checking(struct i387_fxsave_struct __user *fx) 
  96{ 
  97        int err;
  98        asm volatile("1:  rex64 ; fxsave (%[fx])\n\t"
  99                     "2:\n"
 100                     ".section .fixup,\"ax\"\n"
 101                     "3:  movl $-1,%[err]\n"
 102                     "    jmp  2b\n"
 103                     ".previous\n"
 104                     ".section __ex_table,\"a\"\n"
 105                     "   .align 8\n"
 106                     "   .quad  1b,3b\n"
 107                     ".previous"
 108                     : [err] "=r" (err)
 109                     : [fx] "r" (fx), "0" (0)); 
 110        if (unlikely(err))
 111                __clear_user(fx, sizeof(struct i387_fxsave_struct));
 112        return err;
 113} 
 114
 115static inline void kernel_fpu_begin(void)
 116{
 117        struct thread_info *me = current_thread_info();
 118        preempt_disable();
 119        if (me->status & TS_USEDFPU) { 
 120                asm volatile("rex64 ; fxsave %0 ; fnclex"
 121                              : "=m" (me->task->thread.i387.fxsave));
 122                me->status &= ~TS_USEDFPU;
 123                return;
 124        }
 125        clts();
 126}
 127
 128static inline void kernel_fpu_end(void)
 129{
 130        stts();
 131        preempt_enable();
 132}
 133
 134static inline void save_init_fpu( struct task_struct *tsk )
 135{
 136        asm volatile( "rex64 ; fxsave %0 ; fnclex"
 137                      : "=m" (tsk->thread.i387.fxsave));
 138        tsk->thread_info->status &= ~TS_USEDFPU;
 139        stts();
 140}
 141
 142/* 
 143 * This restores directly out of user space. Exceptions are handled.
 144 */
 145static inline int restore_i387(struct _fpstate __user *buf)
 146{
 147        return restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
 148}
 149
 150#endif /* __ASM_X86_64_I387_H */
 151