fpu.h

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/*
 * Copyright (C) 2002 MontaVista Software Inc.
 * Author: Jun Sun, [email protected] or [email protected]
 *
 * 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 void fpu_emulator_init_fpu(void);
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 */