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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
28struct sigcontext;
29struct sigcontext32;
30
31extern void fpu_emulator_init_fpu(void);
32extern void _init_fpu(void);
33extern void _save_fp(struct task_struct *);
34extern void _restore_fp(struct task_struct *);
35
36#define __enable_fpu() \
37do { \
38 set_c0_status(ST0_CU1); \
39 enable_fpu_hazard(); \
40} while (0)
41
42#define __disable_fpu() \
43do { \
44 clear_c0_status(ST0_CU1); \
45 disable_fpu_hazard(); \
46} while (0)
47
48#define enable_fpu() \
49do { \
50 if (cpu_has_fpu) \
51 __enable_fpu(); \
52} while (0)
53
54#define disable_fpu() \
55do { \
56 if (cpu_has_fpu) \
57 __disable_fpu(); \
58} while (0)
59
60
61#define clear_fpu_owner() clear_thread_flag(TIF_USEDFPU)
62
63static inline int __is_fpu_owner(void)
64{
65 return test_thread_flag(TIF_USEDFPU);
66}
67
68static inline int is_fpu_owner(void)
69{
70 return cpu_has_fpu && __is_fpu_owner();
71}
72
73static inline void __own_fpu(void)
74{
75 __enable_fpu();
76 KSTK_STATUS(current) |= ST0_CU1;
77 set_thread_flag(TIF_USEDFPU);
78}
79
80static 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
89static inline void own_fpu(int restore)
90{
91 preempt_disable();
92 own_fpu_inatomic(restore);
93 preempt_enable();
94}
95
96static 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
109static 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
121static inline void save_fp(struct task_struct *tsk)
122{
123 if (cpu_has_fpu)
124 _save_fp(tsk);
125}
126
127static inline void restore_fp(struct task_struct *tsk)
128{
129 if (cpu_has_fpu)
130 _restore_fp(tsk);
131}
132
133static 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 */
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
28struct sigcontext;
29struct sigcontext32;
30
31extern void fpu_emulator_init_fpu(void);
32extern void _init_fpu(void);
33extern void _save_fp(struct task_struct *);
34extern void _restore_fp(struct task_struct *);
35
36/*
37 * This enum specifies a mode in which we want the FPU to operate, for cores
38 * which implement the Status.FR bit. Note that FPU_32BIT & FPU_64BIT
39 * purposefully have the values 0 & 1 respectively, so that an integer value
40 * of Status.FR can be trivially casted to the corresponding enum fpu_mode.
41 */
42enum fpu_mode {
43 FPU_32BIT = 0, /* FR = 0 */
44 FPU_64BIT, /* FR = 1 */
45 FPU_AS_IS,
46};
47
48static inline int __enable_fpu(enum fpu_mode mode)
49{
50 int fr;
51
52 switch (mode) {
53 case FPU_AS_IS:
54 /* just enable the FPU in its current mode */
55 set_c0_status(ST0_CU1);
56 enable_fpu_hazard();
57 return 0;
58
59 case FPU_64BIT:
60#if !(defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_64BIT))
61 /* we only have a 32-bit FPU */
62 return SIGFPE;
63#endif
64 /* fall through */
65 case FPU_32BIT:
66 /* set CU1 & change FR appropriately */
67 fr = (int)mode;
68 change_c0_status(ST0_CU1 | ST0_FR, ST0_CU1 | (fr ? ST0_FR : 0));
69 enable_fpu_hazard();
70
71 /* check FR has the desired value */
72 return (!!(read_c0_status() & ST0_FR) == !!fr) ? 0 : SIGFPE;
73
74 default:
75 BUG();
76 }
77
78 return SIGFPE;
79}
80
81#define __disable_fpu() \
82do { \
83 clear_c0_status(ST0_CU1); \
84 disable_fpu_hazard(); \
85} while (0)
86
87#define clear_fpu_owner() clear_thread_flag(TIF_USEDFPU)
88
89static inline int __is_fpu_owner(void)
90{
91 return test_thread_flag(TIF_USEDFPU);
92}
93
94static inline int is_fpu_owner(void)
95{
96 return cpu_has_fpu && __is_fpu_owner();
97}
98
99static inline int __own_fpu(void)
100{
101 enum fpu_mode mode;
102 int ret;
103
104 mode = !test_thread_flag(TIF_32BIT_FPREGS);
105 ret = __enable_fpu(mode);
106 if (ret)
107 return ret;
108
109 KSTK_STATUS(current) |= ST0_CU1;
110 if (mode == FPU_64BIT)
111 KSTK_STATUS(current) |= ST0_FR;
112 else /* mode == FPU_32BIT */
113 KSTK_STATUS(current) &= ~ST0_FR;
114
115 set_thread_flag(TIF_USEDFPU);
116 return 0;
117}
118
119static inline int own_fpu_inatomic(int restore)
120{
121 int ret = 0;
122
123 if (cpu_has_fpu && !__is_fpu_owner()) {
124 ret = __own_fpu();
125 if (restore && !ret)
126 _restore_fp(current);
127 }
128 return ret;
129}
130
131static inline int own_fpu(int restore)
132{
133 int ret;
134
135 preempt_disable();
136 ret = own_fpu_inatomic(restore);
137 preempt_enable();
138 return ret;
139}
140
141static inline void lose_fpu(int save)
142{
143 preempt_disable();
144 if (is_fpu_owner()) {
145 if (save)
146 _save_fp(current);
147 KSTK_STATUS(current) &= ~ST0_CU1;
148 clear_thread_flag(TIF_USEDFPU);
149 __disable_fpu();
150 }
151 preempt_enable();
152}
153
154static inline int init_fpu(void)
155{
156 int ret = 0;
157
158 preempt_disable();
159 if (cpu_has_fpu) {
160 ret = __own_fpu();
161 if (!ret)
162 _init_fpu();
163 } else {
164 fpu_emulator_init_fpu();
165 }
166
167 preempt_enable();
168 return ret;
169}
170
171static inline void save_fp(struct task_struct *tsk)
172{
173 if (cpu_has_fpu)
174 _save_fp(tsk);
175}
176
177static inline void restore_fp(struct task_struct *tsk)
178{
179 if (cpu_has_fpu)
180 _restore_fp(tsk);
181}
182
183static inline union fpureg *get_fpu_regs(struct task_struct *tsk)
184{
185 if (tsk == current) {
186 preempt_disable();
187 if (is_fpu_owner())
188 _save_fp(current);
189 preempt_enable();
190 }
191
192 return tsk->thread.fpu.fpr;
193}
194
195#endif /* _ASM_FPU_H */