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fpu.h

/*
 * Copyright (C) 2002 MontaVista Software Inc.
 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */
#ifndef _ASM_FPU_H
#define _ASM_FPU_H

#include <linux/sched.h>
#include <linux/thread_info.h>
#include <linux/bitops.h>

#include <asm/mipsregs.h>
#include <asm/cpu.h>
#include <asm/cpu-features.h>
#include <asm/hazards.h>
#include <asm/processor.h>
#include <asm/current.h>

#ifdef CONFIG_MIPS_MT_FPAFF
#include <asm/mips_mt.h>
#endif

struct sigcontext;
struct sigcontext32;

extern asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
extern asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);

extern asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
extern asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);

extern void fpu_emulator_init_fpu(void);
extern int fpu_emulator_save_context(struct sigcontext __user *sc);
extern int fpu_emulator_restore_context(struct sigcontext __user *sc);
extern void _init_fpu(void);
extern void _save_fp(struct task_struct *);
extern void _restore_fp(struct task_struct *);

#define __enable_fpu()                                      \
do {                                                  \
        set_c0_status(ST0_CU1);                                   \
        enable_fpu_hazard();                                \
} while (0)

#define __disable_fpu()                                     \
do {                                                  \
      clear_c0_status(ST0_CU1);                             \
        disable_fpu_hazard();                               \
} while (0)

#define enable_fpu()                                        \
do {                                                  \
      if (cpu_has_fpu)                                \
            __enable_fpu();                                 \
} while (0)

#define disable_fpu()                                       \
do {                                                  \
      if (cpu_has_fpu)                                \
            __disable_fpu();                          \
} while (0)


#define clear_fpu_owner()     clear_thread_flag(TIF_USEDFPU)

static inline int __is_fpu_owner(void)
{
      return test_thread_flag(TIF_USEDFPU);
}

static inline int is_fpu_owner(void)
{
      return cpu_has_fpu && __is_fpu_owner();
}

static inline void __own_fpu(void)
{
      __enable_fpu();
      KSTK_STATUS(current) |= ST0_CU1;
      set_thread_flag(TIF_USEDFPU);
}

static inline void own_fpu_inatomic(int restore)
{
      if (cpu_has_fpu && !__is_fpu_owner()) {
            __own_fpu();
            if (restore)
                  _restore_fp(current);
      }
}

static inline void own_fpu(int restore)
{
      preempt_disable();
      own_fpu_inatomic(restore);
      preempt_enable();
}

static inline void lose_fpu(int save)
{
      preempt_disable();
      if (is_fpu_owner()) {
            if (save)
                  _save_fp(current);
            KSTK_STATUS(current) &= ~ST0_CU1;
            clear_thread_flag(TIF_USEDFPU);
            __disable_fpu();
      }
      preempt_enable();
}

static inline void init_fpu(void)
{
      preempt_disable();
      if (cpu_has_fpu) {
            __own_fpu();
            _init_fpu();
      } else {
            fpu_emulator_init_fpu();
      }
      preempt_enable();
}

static inline void save_fp(struct task_struct *tsk)
{
      if (cpu_has_fpu)
            _save_fp(tsk);
}

static inline void restore_fp(struct task_struct *tsk)
{
      if (cpu_has_fpu)
            _restore_fp(tsk);
}

static inline fpureg_t *get_fpu_regs(struct task_struct *tsk)
{
      if (tsk == current) {
            preempt_disable();
            if (is_fpu_owner())
                  _save_fp(current);
            preempt_enable();
      }

      return tsk->thread.fpu.fpr;
}

#endif /* _ASM_FPU_H */

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