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 __fpu_enabled() (read_c0_status() & ST0_CU1)
  72
  73 #define enable_fpu()                                                    \
  74 do {                                                                    \
  75         if (cpu_has_fpu)                                                \
  76                 __enable_fpu();                                         \
  77 } while (0)
  78
  79 #define disable_fpu()                                                   \
  80 do {                                                                    \
  81         if (cpu_has_fpu)                                                \
  82                 __disable_fpu();                                        \
  83 } while (0)
  84
  85
  86 #define clear_fpu_owner()       clear_thread_flag(TIF_USEDFPU)
  87
  88 static inline int __is_fpu_owner(void)
  89 {
  90         return test_thread_flag(TIF_USEDFPU);
  91 }
  92
  93 static inline int is_fpu_owner(void)
  94 {
  95         return cpu_has_fpu && __is_fpu_owner();
  96 }
  97
  98 static inline void __own_fpu(void)
  99 {
 100         __enable_fpu();
 101         KSTK_STATUS(current) |= ST0_CU1;
 102         set_thread_flag(TIF_USEDFPU);
 103 }
 104
 105 static inline void own_fpu(int restore)
 106 {
 107         preempt_disable();
 108         if (cpu_has_fpu && !__is_fpu_owner()) {
 109                 __own_fpu();
 110                 if (restore)
 111                         _restore_fp(current);
 112         }
 113         preempt_enable();
 114 }
 115
 116 static inline void lose_fpu(int save)
 117 {
 118         preempt_disable();
 119         if (is_fpu_owner()) {
 120                 if (save)
 121                         _save_fp(current);
 122                 KSTK_STATUS(current) &= ~ST0_CU1;
 123                 clear_thread_flag(TIF_USEDFPU);
 124                 __disable_fpu();
 125         }
 126         preempt_enable();
 127 }
 128
 129 static inline void init_fpu(void)
 130 {
 131         preempt_disable();
 132         if (cpu_has_fpu) {
 133                 __own_fpu();
 134                 _init_fpu();
 135         } else {
 136                 fpu_emulator_init_fpu();
 137         }
 138         preempt_enable();
 139 }
 140
 141 static inline void save_fp(struct task_struct *tsk)
 142 {
 143         if (cpu_has_fpu)
 144                 _save_fp(tsk);
 145 }
 146
 147 static inline void restore_fp(struct task_struct *tsk)
 148 {
 149         if (cpu_has_fpu)
 150                 _restore_fp(tsk);
 151 }
 152
 153 static inline fpureg_t *get_fpu_regs(struct task_struct *tsk)
 154 {
 155         if (tsk == current) {
 156                 preempt_disable();
 157                 if (is_fpu_owner())
 158                         _save_fp(current);
 159                 preempt_enable();
 160         }
 161
 162         return tsk->thread.fpu.fpr;
 163 }
 164
 165 static inline void enable_fp_in_kernel(void)
 166 {
 167         set_thread_flag(TIF_ALLOW_FP_IN_KERNEL);
 168         /* make sure CU1 and FPU ownership are consistent */
 169         if (!__is_fpu_owner() && __fpu_enabled())
 170                 __disable_fpu();
 171 }
 172
 173 static inline void disable_fp_in_kernel(void)
 174 {
 175         BUG_ON(!__is_fpu_owner() && __fpu_enabled());
 176         clear_thread_flag(TIF_ALLOW_FP_IN_KERNEL);
 177 }
 178
 179 #endif /* _ASM_FPU_H */