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1da177e4 LT |
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 | ||
1da177e4 LT |
13 | #include <linux/sched.h> |
14 | #include <linux/thread_info.h> | |
1977f032 | 15 | #include <linux/bitops.h> |
1da177e4 LT |
16 | |
17 | #include <asm/mipsregs.h> | |
18 | #include <asm/cpu.h> | |
19 | #include <asm/cpu-features.h> | |
e0cc3a42 | 20 | #include <asm/fpu_emulator.h> |
0b624956 | 21 | #include <asm/hazards.h> |
1da177e4 LT |
22 | #include <asm/processor.h> |
23 | #include <asm/current.h> | |
33c771ba | 24 | #include <asm/msa.h> |
1da177e4 | 25 | |
f088fc84 RB |
26 | #ifdef CONFIG_MIPS_MT_FPAFF |
27 | #include <asm/mips_mt.h> | |
28 | #endif | |
29 | ||
1da177e4 LT |
30 | struct sigcontext; |
31 | struct sigcontext32; | |
32 | ||
1da177e4 LT |
33 | extern void _init_fpu(void); |
34 | extern void _save_fp(struct task_struct *); | |
35 | extern void _restore_fp(struct task_struct *); | |
36 | ||
597ce172 PB |
37 | /* |
38 | * This enum specifies a mode in which we want the FPU to operate, for cores | |
4227a2d4 PB |
39 | * which implement the Status.FR bit. Note that the bottom bit of the value |
40 | * purposefully matches the desired value of the Status.FR bit. | |
597ce172 PB |
41 | */ |
42 | enum fpu_mode { | |
43 | FPU_32BIT = 0, /* FR = 0 */ | |
4227a2d4 | 44 | FPU_64BIT, /* FR = 1, FRE = 0 */ |
597ce172 | 45 | FPU_AS_IS, |
4227a2d4 PB |
46 | FPU_HYBRID, /* FR = 1, FRE = 1 */ |
47 | ||
48 | #define FPU_FR_MASK 0x1 | |
597ce172 PB |
49 | }; |
50 | ||
51 | static inline int __enable_fpu(enum fpu_mode mode) | |
52 | { | |
53 | int fr; | |
54 | ||
55 | switch (mode) { | |
56 | case FPU_AS_IS: | |
57 | /* just enable the FPU in its current mode */ | |
58 | set_c0_status(ST0_CU1); | |
59 | enable_fpu_hazard(); | |
60 | return 0; | |
61 | ||
4227a2d4 PB |
62 | case FPU_HYBRID: |
63 | if (!cpu_has_fre) | |
64 | return SIGFPE; | |
65 | ||
66 | /* set FRE */ | |
67 | write_c0_config5(read_c0_config5() | MIPS_CONF5_FRE); | |
68 | goto fr_common; | |
69 | ||
597ce172 | 70 | case FPU_64BIT: |
f5868f05 | 71 | #if !(defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_64BIT)) |
597ce172 PB |
72 | /* we only have a 32-bit FPU */ |
73 | return SIGFPE; | |
74 | #endif | |
75 | /* fall through */ | |
76 | case FPU_32BIT: | |
4227a2d4 PB |
77 | /* clear FRE */ |
78 | write_c0_config5(read_c0_config5() & ~MIPS_CONF5_FRE); | |
79 | fr_common: | |
597ce172 | 80 | /* set CU1 & change FR appropriately */ |
4227a2d4 | 81 | fr = (int)mode & FPU_FR_MASK; |
597ce172 PB |
82 | change_c0_status(ST0_CU1 | ST0_FR, ST0_CU1 | (fr ? ST0_FR : 0)); |
83 | enable_fpu_hazard(); | |
84 | ||
85 | /* check FR has the desired value */ | |
86 | return (!!(read_c0_status() & ST0_FR) == !!fr) ? 0 : SIGFPE; | |
87 | ||
88 | default: | |
89 | BUG(); | |
90 | } | |
97b8b16b AK |
91 | |
92 | return SIGFPE; | |
597ce172 | 93 | } |
1da177e4 LT |
94 | |
95 | #define __disable_fpu() \ | |
96 | do { \ | |
97 | clear_c0_status(ST0_CU1); \ | |
70342287 | 98 | disable_fpu_hazard(); \ |
1da177e4 LT |
99 | } while (0) |
100 | ||
1da177e4 LT |
101 | #define clear_fpu_owner() clear_thread_flag(TIF_USEDFPU) |
102 | ||
1d74f6bc RB |
103 | static inline int __is_fpu_owner(void) |
104 | { | |
105 | return test_thread_flag(TIF_USEDFPU); | |
106 | } | |
107 | ||
1da177e4 LT |
108 | static inline int is_fpu_owner(void) |
109 | { | |
1d74f6bc | 110 | return cpu_has_fpu && __is_fpu_owner(); |
1da177e4 LT |
111 | } |
112 | ||
597ce172 | 113 | static inline int __own_fpu(void) |
1da177e4 | 114 | { |
597ce172 PB |
115 | enum fpu_mode mode; |
116 | int ret; | |
117 | ||
4227a2d4 PB |
118 | if (test_thread_flag(TIF_HYBRID_FPREGS)) |
119 | mode = FPU_HYBRID; | |
120 | else | |
121 | mode = !test_thread_flag(TIF_32BIT_FPREGS); | |
122 | ||
597ce172 PB |
123 | ret = __enable_fpu(mode); |
124 | if (ret) | |
125 | return ret; | |
126 | ||
53dc8028 | 127 | KSTK_STATUS(current) |= ST0_CU1; |
4227a2d4 | 128 | if (mode == FPU_64BIT || mode == FPU_HYBRID) |
597ce172 PB |
129 | KSTK_STATUS(current) |= ST0_FR; |
130 | else /* mode == FPU_32BIT */ | |
131 | KSTK_STATUS(current) &= ~ST0_FR; | |
132 | ||
53dc8028 | 133 | set_thread_flag(TIF_USEDFPU); |
597ce172 | 134 | return 0; |
53dc8028 AN |
135 | } |
136 | ||
597ce172 | 137 | static inline int own_fpu_inatomic(int restore) |
53dc8028 | 138 | { |
597ce172 PB |
139 | int ret = 0; |
140 | ||
53dc8028 | 141 | if (cpu_has_fpu && !__is_fpu_owner()) { |
597ce172 PB |
142 | ret = __own_fpu(); |
143 | if (restore && !ret) | |
53dc8028 | 144 | _restore_fp(current); |
1da177e4 | 145 | } |
597ce172 | 146 | return ret; |
faea6234 AN |
147 | } |
148 | ||
597ce172 | 149 | static inline int own_fpu(int restore) |
faea6234 | 150 | { |
597ce172 PB |
151 | int ret; |
152 | ||
faea6234 | 153 | preempt_disable(); |
597ce172 | 154 | ret = own_fpu_inatomic(restore); |
53dc8028 | 155 | preempt_enable(); |
597ce172 | 156 | return ret; |
1da177e4 LT |
157 | } |
158 | ||
53dc8028 | 159 | static inline void lose_fpu(int save) |
1da177e4 | 160 | { |
53dc8028 | 161 | preempt_disable(); |
33c771ba PB |
162 | if (is_msa_enabled()) { |
163 | if (save) { | |
164 | save_msa(current); | |
842dfc11 ML |
165 | current->thread.fpu.fcr31 = |
166 | read_32bit_cp1_register(CP1_STATUS); | |
33c771ba PB |
167 | } |
168 | disable_msa(); | |
169 | clear_thread_flag(TIF_USEDMSA); | |
170 | } else if (is_fpu_owner()) { | |
53dc8028 AN |
171 | if (save) |
172 | _save_fp(current); | |
1da177e4 LT |
173 | __disable_fpu(); |
174 | } | |
33c771ba PB |
175 | KSTK_STATUS(current) &= ~ST0_CU1; |
176 | clear_thread_flag(TIF_USEDFPU); | |
53dc8028 | 177 | preempt_enable(); |
1da177e4 LT |
178 | } |
179 | ||
597ce172 | 180 | static inline int init_fpu(void) |
1da177e4 | 181 | { |
597ce172 PB |
182 | int ret = 0; |
183 | ||
1da177e4 | 184 | if (cpu_has_fpu) { |
597ce172 | 185 | ret = __own_fpu(); |
4227a2d4 PB |
186 | if (!ret) { |
187 | unsigned int config5 = read_c0_config5(); | |
188 | ||
189 | /* | |
190 | * Ensure FRE is clear whilst running _init_fpu, since | |
191 | * single precision FP instructions are used. If FRE | |
192 | * was set then we'll just end up initialising all 32 | |
193 | * 64b registers. | |
194 | */ | |
195 | write_c0_config5(config5 & ~MIPS_CONF5_FRE); | |
196 | enable_fpu_hazard(); | |
197 | ||
597ce172 | 198 | _init_fpu(); |
4227a2d4 PB |
199 | |
200 | /* Restore FRE */ | |
201 | write_c0_config5(config5); | |
202 | enable_fpu_hazard(); | |
203 | } | |
e0cc3a42 | 204 | } else |
1da177e4 | 205 | fpu_emulator_init_fpu(); |
597ce172 | 206 | |
597ce172 | 207 | return ret; |
1da177e4 LT |
208 | } |
209 | ||
210 | static inline void save_fp(struct task_struct *tsk) | |
211 | { | |
212 | if (cpu_has_fpu) | |
213 | _save_fp(tsk); | |
214 | } | |
215 | ||
216 | static inline void restore_fp(struct task_struct *tsk) | |
217 | { | |
218 | if (cpu_has_fpu) | |
219 | _restore_fp(tsk); | |
220 | } | |
221 | ||
bbd426f5 | 222 | static inline union fpureg *get_fpu_regs(struct task_struct *tsk) |
1da177e4 | 223 | { |
e04582b7 AN |
224 | if (tsk == current) { |
225 | preempt_disable(); | |
226 | if (is_fpu_owner()) | |
1da177e4 | 227 | _save_fp(current); |
e04582b7 | 228 | preempt_enable(); |
1da177e4 LT |
229 | } |
230 | ||
eae89076 | 231 | return tsk->thread.fpu.fpr; |
1da177e4 LT |
232 | } |
233 | ||
234 | #endif /* _ASM_FPU_H */ |