include/asm-x86_64/i387.h

   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
  22 extern void fpu_init(void);
  23 extern unsigned int mxcsr_feature_mask;
  24 extern void mxcsr_feature_mask_init(void);
  25 extern void init_fpu(struct task_struct *child);
  26 extern 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 */
  38 static 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  */
  59 extern int get_fpregs(struct user_i387_struct __user *buf,
  60                       struct task_struct *tsk);
  61 extern 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
  75 static 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
  95 static 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
 115 static 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
 128 static inline void kernel_fpu_end(void)
 129 {
 130         stts();
 131         preempt_enable();
 132 }
 133
 134 static 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  */
 145 static 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 */