include/asm-mips/fpu.h

   1 /*
   2  * Copyright (C) 2002 MontaVista Software Inc.
   3  * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation;  either version 2 of the  License, or (at your
   8  * option) any later version.
   9  */
  10 #ifndef _ASM_FPU_H
  11 #define _ASM_FPU_H
  12
  13 #include <linux/sched.h>
  14 #include <linux/thread_info.h>
  15
  16 #include <asm/mipsregs.h>
  17 #include <asm/cpu.h>
  18 #include <asm/cpu-features.h>
  19 #include <asm/bitops.h>
  20 #include <asm/processor.h>
  21 #include <asm/current.h>
  22
  23 #ifdef CONFIG_MIPS_MT_FPAFF
  24 #include <asm/mips_mt.h>
  25 #endif
  26
  27 struct sigcontext;
  28 struct sigcontext32;
  29
  30 extern asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
  31 extern asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
  32
  33 extern asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
  34 extern asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
  35
  36 extern void fpu_emulator_init_fpu(void);
  37 extern void _init_fpu(void);
  38 extern void _save_fp(struct task_struct *);
  39 extern void _restore_fp(struct task_struct *);
  40
  41 #if defined(CONFIG_CPU_SB1)
  42 #define __enable_fpu_hazard()                                           \
  43 do {                                                                    \
  44         asm(".set       push            \n\t"                           \
  45             ".set       mips64          \n\t"                           \
  46             ".set       noreorder       \n\t"                           \
  47             "ssnop                      \n\t"                           \
  48             "bnezl      $0, .+4         \n\t"                           \
  49             "ssnop                      \n\t"                           \
  50             ".set pop");                                                \
  51 } while (0)
  52 #else
  53 #define __enable_fpu_hazard()                                           \
  54 do {                                                                    \
  55         asm("nop;nop;nop;nop");         /* max. hazard */               \
  56 } while (0)
  57 #endif
  58
  59 #define __enable_fpu()                                                  \
  60 do {                                                                    \
  61         set_c0_status(ST0_CU1);                                         \
  62         __enable_fpu_hazard();                                          \
  63 } while (0)
  64
  65 #define __disable_fpu()                                                 \
  66 do {                                                                    \
  67         clear_c0_status(ST0_CU1);                                       \
  68         /* We don't care about the c0 hazard here  */                   \
  69 } while (0)
  70
  71 #define enable_fpu()                                                    \
  72 do {                                                                    \
  73         if (cpu_has_fpu)                                                \
  74                 __enable_fpu();                                         \
  75 } while (0)
  76
  77 #define disable_fpu()                                                   \
  78 do {                                                                    \
  79         if (cpu_has_fpu)                                                \
  80                 __disable_fpu();                                        \
  81 } while (0)
  82
  83
  84 #define clear_fpu_owner()       clear_thread_flag(TIF_USEDFPU)
  85
  86 static inline int __is_fpu_owner(void)
  87 {
  88         return test_thread_flag(TIF_USEDFPU);
  89 }
  90
  91 static inline int is_fpu_owner(void)
  92 {
  93         return cpu_has_fpu && __is_fpu_owner();
  94 }
  95
  96 static inline void __own_fpu(void)
  97 {
  98         __enable_fpu();
  99         KSTK_STATUS(current) |= ST0_CU1;
 100         set_thread_flag(TIF_USEDFPU);
 101 }
 102
 103 static inline void own_fpu_inatomic(int restore)
 104 {
 105         if (cpu_has_fpu && !__is_fpu_owner()) {
 106                 __own_fpu();
 107                 if (restore)
 108                         _restore_fp(current);
 109         }
 110 }
 111
 112 static inline void own_fpu(int restore)
 113 {
 114         preempt_disable();
 115         own_fpu_inatomic(restore);
 116         preempt_enable();
 117 }
 118
 119 static inline void lose_fpu(int save)
 120 {
 121         preempt_disable();
 122         if (is_fpu_owner()) {
 123                 if (save)
 124                         _save_fp(current);
 125                 KSTK_STATUS(current) &= ~ST0_CU1;
 126                 clear_thread_flag(TIF_USEDFPU);
 127                 __disable_fpu();
 128         }
 129         preempt_enable();
 130 }
 131
 132 static inline void init_fpu(void)
 133 {
 134         preempt_disable();
 135         if (cpu_has_fpu) {
 136                 __own_fpu();
 137                 _init_fpu();
 138         } else {
 139                 fpu_emulator_init_fpu();
 140         }
 141         preempt_enable();
 142 }
 143
 144 static inline void save_fp(struct task_struct *tsk)
 145 {
 146         if (cpu_has_fpu)
 147                 _save_fp(tsk);
 148 }
 149
 150 static inline void restore_fp(struct task_struct *tsk)
 151 {
 152         if (cpu_has_fpu)
 153                 _restore_fp(tsk);
 154 }
 155
 156 static inline fpureg_t *get_fpu_regs(struct task_struct *tsk)
 157 {
 158         if (tsk == current) {
 159                 preempt_disable();
 160                 if (is_fpu_owner())
 161                         _save_fp(current);
 162                 preempt_enable();
 163         }
 164
 165         return tsk->thread.fpu.fpr;
 166 }
 167
 168 #endif /* _ASM_FPU_H */