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 static inline int need_signal_i387(struct task_struct *me)
  29 {
  30         if (!me->used_math)
  31                 return 0;
  32         me->used_math = 0;
  33         if (me->thread_info->status & TS_USEDFPU)
  34                 return 0;
  35         return 1;
  36 }
  37
  38 /*
  39  * FPU lazy state save handling...
  40  */
  41
  42 #define unlazy_fpu(tsk) do { \
  43         if ((tsk)->thread_info->status & TS_USEDFPU) \
  44                 save_init_fpu(tsk); \
  45 } while (0)
  46
  47 /* Ignore delayed exceptions from user space */
  48 static inline void tolerant_fwait(void)
  49 {
  50         asm volatile("1: fwait\n"
  51                      "2:\n"
  52                      "   .section __ex_table,\"a\"\n"
  53                      "  .align 8\n"
  54                      "  .quad 1b,2b\n"
  55                      "  .previous\n");
  56 }
  57
  58 #define clear_fpu(tsk) do { \
  59         if ((tsk)->thread_info->status & TS_USEDFPU) {          \
  60                 tolerant_fwait();                               \
  61                 (tsk)->thread_info->status &= ~TS_USEDFPU;      \
  62                 stts();                                         \
  63         }                                                       \
  64 } while (0)
  65
  66 /*
  67  * ptrace request handers...
  68  */
  69 extern int get_fpregs(struct user_i387_struct __user *buf,
  70                       struct task_struct *tsk);
  71 extern int set_fpregs(struct task_struct *tsk,
  72                       struct user_i387_struct __user *buf);
  73
  74 /*
  75  * i387 state interaction
  76  */
  77 #define get_fpu_mxcsr(t) ((t)->thread.i387.fxsave.mxcsr)
  78 #define get_fpu_cwd(t) ((t)->thread.i387.fxsave.cwd)
  79 #define get_fpu_fxsr_twd(t) ((t)->thread.i387.fxsave.twd)
  80 #define get_fpu_swd(t) ((t)->thread.i387.fxsave.swd)
  81 #define set_fpu_cwd(t,val) ((t)->thread.i387.fxsave.cwd = (val))
  82 #define set_fpu_swd(t,val) ((t)->thread.i387.fxsave.swd = (val))
  83 #define set_fpu_fxsr_twd(t,val) ((t)->thread.i387.fxsave.twd = (val))
  84
  85 static inline int restore_fpu_checking(struct i387_fxsave_struct *fx)
  86 {
  87         int err;
  88         asm volatile("1:  rex64 ; fxrstor (%[fx])\n\t"
  89                      "2:\n"
  90                      ".section .fixup,\"ax\"\n"
  91                      "3:  movl $-1,%[err]\n"
  92                      "    jmp  2b\n"
  93                      ".previous\n"
  94                      ".section __ex_table,\"a\"\n"
  95                      "   .align 8\n"
  96                      "   .quad  1b,3b\n"
  97                      ".previous"
  98                      : [err] "=r" (err)
  99                      : [fx] "r" (fx), "0" (0));
 100         if (unlikely(err))
 101                 init_fpu(current);
 102         return err;
 103 }
 104
 105 static inline int save_i387_checking(struct i387_fxsave_struct __user *fx)
 106 {
 107         int err;
 108         asm volatile("1:  rex64 ; fxsave (%[fx])\n\t"
 109                      "2:\n"
 110                      ".section .fixup,\"ax\"\n"
 111                      "3:  movl $-1,%[err]\n"
 112                      "    jmp  2b\n"
 113                      ".previous\n"
 114                      ".section __ex_table,\"a\"\n"
 115                      "   .align 8\n"
 116                      "   .quad  1b,3b\n"
 117                      ".previous"
 118                      : [err] "=r" (err)
 119                      : [fx] "r" (fx), "0" (0));
 120         if (unlikely(err))
 121                 __clear_user(fx, sizeof(struct i387_fxsave_struct));
 122         return err;
 123 }
 124
 125 static inline void kernel_fpu_begin(void)
 126 {
 127         struct thread_info *me = current_thread_info();
 128         preempt_disable();
 129         if (me->status & TS_USEDFPU) {
 130                 asm volatile("rex64 ; fxsave %0 ; fnclex"
 131                               : "=m" (me->task->thread.i387.fxsave));
 132                 me->status &= ~TS_USEDFPU;
 133                 return;
 134         }
 135         clts();
 136 }
 137
 138 static inline void kernel_fpu_end(void)
 139 {
 140         stts();
 141         preempt_enable();
 142 }
 143
 144 static inline void save_init_fpu( struct task_struct *tsk )
 145 {
 146         asm volatile( "rex64 ; fxsave %0 ; fnclex"
 147                       : "=m" (tsk->thread.i387.fxsave));
 148         tsk->thread_info->status &= ~TS_USEDFPU;
 149         stts();
 150 }
 151
 152 /*
 153  * This restores directly out of user space. Exceptions are handled.
 154  */
 155 static inline int restore_i387(struct _fpstate __user *buf)
 156 {
 157         return restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
 158 }
 159
 160 #endif /* __ASM_X86_64_I387_H */