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/*
* 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 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 *);
/*
* This enum specifies a mode in which we want the FPU to operate, for cores
* which implement the Status.FR bit. Note that FPU_32BIT & FPU_64BIT
* purposefully have the values 0 & 1 respectively, so that an integer value
* of Status.FR can be trivially casted to the corresponding enum fpu_mode.
*/
enum fpu_mode {
FPU_32BIT = 0, /* FR = 0 */
FPU_64BIT, /* FR = 1 */
FPU_AS_IS,
};
static inline int __enable_fpu(enum fpu_mode mode)
{
int fr;
switch (mode) {
case FPU_AS_IS:
/* just enable the FPU in its current mode */
set_c0_status(ST0_CU1);
enable_fpu_hazard();
return 0;
case FPU_64BIT:
#if !(defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_64BIT))
/* we only have a 32-bit FPU */
return SIGFPE;
#endif
/* fall through */
case FPU_32BIT:
/* set CU1 & change FR appropriately */
fr = (int)mode;
change_c0_status(ST0_CU1 | ST0_FR, ST0_CU1 | (fr ? ST0_FR : 0));
enable_fpu_hazard();
/* check FR has the desired value */
return (!!(read_c0_status() & ST0_FR) == !!fr) ? 0 : SIGFPE;
default:
BUG();
}
return SIGFPE;
}
#define __disable_fpu() \
do { \
clear_c0_status(ST0_CU1); \
disable_fpu_hazard(); \
} 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 int __own_fpu(void)
{
enum fpu_mode mode;
int ret;
mode = !test_thread_flag(TIF_32BIT_FPREGS);
ret = __enable_fpu(mode);
if (ret)
return ret;
KSTK_STATUS(current) |= ST0_CU1;
if (mode == FPU_64BIT)
KSTK_STATUS(current) |= ST0_FR;
else /* mode == FPU_32BIT */
KSTK_STATUS(current) &= ~ST0_FR;
set_thread_flag(TIF_USEDFPU);
return 0;
}
static inline int own_fpu_inatomic(int restore)
{
int ret = 0;
if (cpu_has_fpu && !__is_fpu_owner()) {
ret = __own_fpu();
if (restore && !ret)
_restore_fp(current);
}
return ret;
}
static inline int own_fpu(int restore)
{
int ret;
preempt_disable();
ret = own_fpu_inatomic(restore);
preempt_enable();
return ret;
}
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 int init_fpu(void)
{
int ret = 0;
preempt_disable();
if (cpu_has_fpu) {
ret = __own_fpu();
if (!ret)
_init_fpu();
} else {
fpu_emulator_init_fpu();
}
preempt_enable();
return ret;
}
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 union fpureg *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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