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fpu.h
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1 /* MN10300 FPU definitions
2  *
3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells ([email protected])
5  * Derived from include/asm-i386/i387.h: Copyright (C) 1994 Linus Torvalds
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public Licence
9  * as published by the Free Software Foundation; either version
10  * 2 of the Licence, or (at your option) any later version.
11  */
12 #ifndef _ASM_FPU_H
13 #define _ASM_FPU_H
14 
15 #ifndef __ASSEMBLY__
16 
17 #include <linux/sched.h>
18 #include <asm/exceptions.h>
19 #include <asm/sigcontext.h>
20 
21 #ifdef __KERNEL__
22 
23 extern asmlinkage void fpu_disabled(void);
24 
25 #ifdef CONFIG_FPU
26 
27 #ifdef CONFIG_LAZY_SAVE_FPU
28 /* the task that currently owns the FPU state */
29 extern struct task_struct *fpu_state_owner;
30 #endif
31 
32 #if (THREAD_USING_FPU & ~0xff)
33 #error THREAD_USING_FPU must be smaller than 0x100.
34 #endif
35 
36 static inline void set_using_fpu(struct task_struct *tsk)
37 {
38  asm volatile(
39  "bset %0,(0,%1)"
40  :
41  : "i"(THREAD_USING_FPU), "a"(&tsk->thread.fpu_flags)
42  : "memory", "cc");
43 }
44 
45 static inline void clear_using_fpu(struct task_struct *tsk)
46 {
47  asm volatile(
48  "bclr %0,(0,%1)"
49  :
50  : "i"(THREAD_USING_FPU), "a"(&tsk->thread.fpu_flags)
51  : "memory", "cc");
52 }
53 
54 #define is_using_fpu(tsk) ((tsk)->thread.fpu_flags & THREAD_USING_FPU)
55 
56 extern asmlinkage void fpu_kill_state(struct task_struct *);
57 extern asmlinkage void fpu_exception(struct pt_regs *, enum exception_code);
58 extern asmlinkage void fpu_init_state(void);
59 extern asmlinkage void fpu_save(struct fpu_state_struct *);
60 extern int fpu_setup_sigcontext(struct fpucontext *buf);
61 extern int fpu_restore_sigcontext(struct fpucontext *buf);
62 
63 static inline void unlazy_fpu(struct task_struct *tsk)
64 {
66 #ifndef CONFIG_LAZY_SAVE_FPU
67  if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
68  fpu_save(&tsk->thread.fpu_state);
69  tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
70  tsk->thread.uregs->epsw &= ~EPSW_FE;
71  }
72 #else
73  if (fpu_state_owner == tsk)
74  fpu_save(&tsk->thread.fpu_state);
75 #endif
77 }
78 
79 static inline void exit_fpu(void)
80 {
81 #ifdef CONFIG_LAZY_SAVE_FPU
82  struct task_struct *tsk = current;
83 
85  if (fpu_state_owner == tsk)
86  fpu_state_owner = NULL;
88 #endif
89 }
90 
91 static inline void flush_fpu(void)
92 {
93  struct task_struct *tsk = current;
94 
96 #ifndef CONFIG_LAZY_SAVE_FPU
97  if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
98  tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
99  tsk->thread.uregs->epsw &= ~EPSW_FE;
100  }
101 #else
102  if (fpu_state_owner == tsk) {
103  fpu_state_owner = NULL;
104  tsk->thread.uregs->epsw &= ~EPSW_FE;
105  }
106 #endif
107  preempt_enable();
108  clear_using_fpu(tsk);
109 }
110 
111 #else /* CONFIG_FPU */
112 
113 extern asmlinkage
114 void unexpected_fpu_exception(struct pt_regs *, enum exception_code);
115 #define fpu_exception unexpected_fpu_exception
116 
117 struct task_struct;
118 struct fpu_state_struct;
119 static inline bool is_using_fpu(struct task_struct *tsk) { return false; }
120 static inline void set_using_fpu(struct task_struct *tsk) {}
121 static inline void clear_using_fpu(struct task_struct *tsk) {}
122 static inline void fpu_init_state(void) {}
123 static inline void fpu_save(struct fpu_state_struct *s) {}
124 static inline void fpu_kill_state(struct task_struct *tsk) {}
125 static inline void unlazy_fpu(struct task_struct *tsk) {}
126 static inline void exit_fpu(void) {}
127 static inline void flush_fpu(void) {}
128 static inline int fpu_setup_sigcontext(struct fpucontext *buf) { return 0; }
129 static inline int fpu_restore_sigcontext(struct fpucontext *buf) { return 0; }
130 #endif /* CONFIG_FPU */
131 
132 #endif /* __KERNEL__ */
133 #endif /* !__ASSEMBLY__ */
134 #endif /* _ASM_FPU_H */