tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
16#include <asm/mipsregs.h>
17#include <asm/cpu.h>
18#include <asm/cpu-features.h>
19#include <asm/bitops.h>
20#include <asm/processor.h>
21#include <asm/current.h>
22
23#ifdef CONFIG_MIPS_MT_FPAFF
24#include <asm/mips_mt.h>
25#endif
26
27struct sigcontext;
28struct sigcontext32;
29
30extern asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
31extern asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
32
33extern asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
34extern asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
35
36extern void fpu_emulator_init_fpu(void);
37extern void _init_fpu(void);
38extern void _save_fp(struct task_struct *);
39extern void _restore_fp(struct task_struct *);
40
41#if defined(CONFIG_CPU_SB1)
42#define __enable_fpu_hazard() \
43do { \
44 asm(".set push \n\t" \
45 ".set mips64 \n\t" \
46 ".set noreorder \n\t" \
47 "ssnop \n\t" \
48 "bnezl $0, .+4 \n\t" \
49 "ssnop \n\t" \
50 ".set pop"); \
51} while (0)
52#else
53#define __enable_fpu_hazard() \
54do { \
55 asm("nop;nop;nop;nop"); /* max. hazard */ \
56} while (0)
57#endif
58
59#define __enable_fpu() \
60do { \
61 set_c0_status(ST0_CU1); \
62 __enable_fpu_hazard(); \
63} while (0)
64
65#define __disable_fpu() \
66do { \
67 clear_c0_status(ST0_CU1); \
68 /* We don't care about the c0 hazard here */ \
69} while (0)
70
71#define __fpu_enabled() (read_c0_status() & ST0_CU1)
72
73#define enable_fpu() \
74do { \
75 if (cpu_has_fpu) \
76 __enable_fpu(); \
77} while (0)
78
79#define disable_fpu() \
80do { \
81 if (cpu_has_fpu) \
82 __disable_fpu(); \
83} while (0)
84
85
86#define clear_fpu_owner() clear_thread_flag(TIF_USEDFPU)
87
88static inline int __is_fpu_owner(void)
89{
90 return test_thread_flag(TIF_USEDFPU);
91}
92
93static inline int is_fpu_owner(void)
94{
95 return cpu_has_fpu && __is_fpu_owner();
96}
97
98static inline void __own_fpu(void)
99{
100 __enable_fpu();
101 KSTK_STATUS(current) |= ST0_CU1;
102 set_thread_flag(TIF_USEDFPU);
103}
104
105static inline void own_fpu(int restore)
106{
107 preempt_disable();
108 if (cpu_has_fpu && !__is_fpu_owner()) {
109 __own_fpu();
110 if (restore)
111 _restore_fp(current);
112 }
113 preempt_enable();
114}
115
116static inline void lose_fpu(int save)
117{
118 preempt_disable();
119 if (is_fpu_owner()) {
120 if (save)
121 _save_fp(current);
122 KSTK_STATUS(current) &= ~ST0_CU1;
123 clear_thread_flag(TIF_USEDFPU);
124 __disable_fpu();
125 }
126 preempt_enable();
127}
128
129static inline void init_fpu(void)
130{
131 preempt_disable();
132 if (cpu_has_fpu) {
133 __own_fpu();
134 _init_fpu();
135 } else {
136 fpu_emulator_init_fpu();
137 }
138 preempt_enable();
139}
140
141static inline void save_fp(struct task_struct *tsk)
142{
143 if (cpu_has_fpu)
144 _save_fp(tsk);
145}
146
147static inline void restore_fp(struct task_struct *tsk)
148{
149 if (cpu_has_fpu)
150 _restore_fp(tsk);
151}
152
153static inline fpureg_t *get_fpu_regs(struct task_struct *tsk)
154{
155 if (tsk == current) {
156 preempt_disable();
157 if (is_fpu_owner())
158 _save_fp(current);
159 preempt_enable();
160 }
161
162 return tsk->thread.fpu.fpr;
163}
164
165static inline void enable_fp_in_kernel(void)
166{
167 set_thread_flag(TIF_ALLOW_FP_IN_KERNEL);
168 /* make sure CU1 and FPU ownership are consistent */
169 if (!__is_fpu_owner() && __fpu_enabled())
170 __disable_fpu();
171}
172
173static inline void disable_fp_in_kernel(void)
174{
175 BUG_ON(!__is_fpu_owner() && __fpu_enabled());
176 clear_thread_flag(TIF_ALLOW_FP_IN_KERNEL);
177}
178
179#endif /* _ASM_FPU_H */