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 #include <linux/bitops.h>
16 
17 #include <asm/mipsregs.h>
18 #include <asm/cpu.h>
19 #include <asm/cpu-features.h>
20 #include <asm/hazards.h>
21 #include <asm/processor.h>
22 #include <asm/current.h>
23 
24 #ifdef CONFIG_MIPS_MT_FPAFF
25 #include <asm/mips_mt.h>
26 #endif
27 
28 struct sigcontext;
29 struct sigcontext32;
30 
31 extern void fpu_emulator_init_fpu(void);
32 extern void _init_fpu(void);
33 extern void _save_fp(struct task_struct *);
34 extern void _restore_fp(struct task_struct *);
35 
36 #define __enable_fpu()							\
37 do {									\
38         set_c0_status(ST0_CU1);						\
39         enable_fpu_hazard();						\
40 } while (0)
41 
42 #define __disable_fpu()							\
43 do {									\
44 	clear_c0_status(ST0_CU1);					\
45         disable_fpu_hazard();						\
46 } while (0)
47 
48 #define enable_fpu()							\
49 do {									\
50 	if (cpu_has_fpu)						\
51 		__enable_fpu();						\
52 } while (0)
53 
54 #define disable_fpu()							\
55 do {									\
56 	if (cpu_has_fpu)						\
57 		__disable_fpu();					\
58 } while (0)
59 
60 
61 #define clear_fpu_owner()	clear_thread_flag(TIF_USEDFPU)
62 
__is_fpu_owner(void)63 static inline int __is_fpu_owner(void)
64 {
65 	return test_thread_flag(TIF_USEDFPU);
66 }
67 
is_fpu_owner(void)68 static inline int is_fpu_owner(void)
69 {
70 	return cpu_has_fpu && __is_fpu_owner();
71 }
72 
__own_fpu(void)73 static inline void __own_fpu(void)
74 {
75 	__enable_fpu();
76 	KSTK_STATUS(current) |= ST0_CU1;
77 	set_thread_flag(TIF_USEDFPU);
78 }
79 
own_fpu_inatomic(int restore)80 static inline void own_fpu_inatomic(int restore)
81 {
82 	if (cpu_has_fpu && !__is_fpu_owner()) {
83 		__own_fpu();
84 		if (restore)
85 			_restore_fp(current);
86 	}
87 }
88 
own_fpu(int restore)89 static inline void own_fpu(int restore)
90 {
91 	preempt_disable();
92 	own_fpu_inatomic(restore);
93 	preempt_enable();
94 }
95 
lose_fpu(int save)96 static inline void lose_fpu(int save)
97 {
98 	preempt_disable();
99 	if (is_fpu_owner()) {
100 		if (save)
101 			_save_fp(current);
102 		KSTK_STATUS(current) &= ~ST0_CU1;
103 		clear_thread_flag(TIF_USEDFPU);
104 		__disable_fpu();
105 	}
106 	preempt_enable();
107 }
108 
init_fpu(void)109 static inline void init_fpu(void)
110 {
111 	preempt_disable();
112 	if (cpu_has_fpu) {
113 		__own_fpu();
114 		_init_fpu();
115 	} else {
116 		fpu_emulator_init_fpu();
117 	}
118 	preempt_enable();
119 }
120 
save_fp(struct task_struct * tsk)121 static inline void save_fp(struct task_struct *tsk)
122 {
123 	if (cpu_has_fpu)
124 		_save_fp(tsk);
125 }
126 
restore_fp(struct task_struct * tsk)127 static inline void restore_fp(struct task_struct *tsk)
128 {
129 	if (cpu_has_fpu)
130 		_restore_fp(tsk);
131 }
132 
get_fpu_regs(struct task_struct * tsk)133 static inline fpureg_t *get_fpu_regs(struct task_struct *tsk)
134 {
135 	if (tsk == current) {
136 		preempt_disable();
137 		if (is_fpu_owner())
138 			_save_fp(current);
139 		preempt_enable();
140 	}
141 
142 	return tsk->thread.fpu.fpr;
143 }
144 
145 #endif /* _ASM_FPU_H */
146