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b920de1b DH |
1 | /* MN10300 FPU management |
2 | * | |
3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public Licence | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the Licence, or (at your option) any later version. | |
10 | */ | |
11 | #include <asm/uaccess.h> | |
12 | #include <asm/fpu.h> | |
13 | #include <asm/elf.h> | |
14 | #include <asm/exceptions.h> | |
15 | ||
278d91c4 | 16 | #ifdef CONFIG_LAZY_SAVE_FPU |
b920de1b | 17 | struct task_struct *fpu_state_owner; |
278d91c4 | 18 | #endif |
b920de1b DH |
19 | |
20 | /* | |
278d91c4 | 21 | * error functions in FPU disabled exception |
b920de1b | 22 | */ |
278d91c4 | 23 | asmlinkage void fpu_disabled_in_kernel(struct pt_regs *regs) |
b920de1b | 24 | { |
278d91c4 AT |
25 | die_if_no_fixup("An FPU Disabled exception happened in kernel space\n", |
26 | regs, EXCEP_FPU_DISABLED); | |
b920de1b DH |
27 | } |
28 | ||
29 | /* | |
30 | * handle an FPU operational exception | |
31 | * - there's a possibility that if the FPU is asynchronous, the signal might | |
32 | * be meant for a process other than the current one | |
33 | */ | |
34 | asmlinkage void fpu_exception(struct pt_regs *regs, enum exception_code code) | |
35 | { | |
278d91c4 | 36 | struct task_struct *tsk = current; |
b920de1b | 37 | siginfo_t info; |
278d91c4 | 38 | u32 fpcr; |
b920de1b DH |
39 | |
40 | if (!user_mode(regs)) | |
41 | die_if_no_fixup("An FPU Operation exception happened in" | |
42 | " kernel space\n", | |
43 | regs, code); | |
44 | ||
278d91c4 | 45 | if (!is_using_fpu(tsk)) |
b920de1b DH |
46 | die_if_no_fixup("An FPU Operation exception happened," |
47 | " but the FPU is not in use", | |
48 | regs, code); | |
49 | ||
50 | info.si_signo = SIGFPE; | |
51 | info.si_errno = 0; | |
52 | info.si_addr = (void *) tsk->thread.uregs->pc; | |
53 | info.si_code = FPE_FLTINV; | |
54 | ||
278d91c4 | 55 | unlazy_fpu(tsk); |
b920de1b | 56 | |
278d91c4 AT |
57 | fpcr = tsk->thread.fpu_state.fpcr; |
58 | ||
59 | if (fpcr & FPCR_EC_Z) | |
60 | info.si_code = FPE_FLTDIV; | |
61 | else if (fpcr & FPCR_EC_O) | |
62 | info.si_code = FPE_FLTOVF; | |
63 | else if (fpcr & FPCR_EC_U) | |
64 | info.si_code = FPE_FLTUND; | |
65 | else if (fpcr & FPCR_EC_I) | |
66 | info.si_code = FPE_FLTRES; | |
b920de1b DH |
67 | |
68 | force_sig_info(SIGFPE, &info, tsk); | |
69 | } | |
70 | ||
71 | /* | |
72 | * save the FPU state to a signal context | |
73 | */ | |
74 | int fpu_setup_sigcontext(struct fpucontext *fpucontext) | |
75 | { | |
b920de1b DH |
76 | struct task_struct *tsk = current; |
77 | ||
78 | if (!is_using_fpu(tsk)) | |
79 | return 0; | |
80 | ||
81 | /* transfer the current FPU state to memory and cause fpu_init() to be | |
82 | * triggered by the next attempted FPU operation by the current | |
83 | * process. | |
84 | */ | |
85 | preempt_disable(); | |
86 | ||
278d91c4 AT |
87 | #ifndef CONFIG_LAZY_SAVE_FPU |
88 | if (tsk->thread.fpu_flags & THREAD_HAS_FPU) { | |
89 | fpu_save(&tsk->thread.fpu_state); | |
90 | tsk->thread.uregs->epsw &= ~EPSW_FE; | |
91 | tsk->thread.fpu_flags &= ~THREAD_HAS_FPU; | |
92 | } | |
93 | #else /* !CONFIG_LAZY_SAVE_FPU */ | |
b920de1b DH |
94 | if (fpu_state_owner == tsk) { |
95 | fpu_save(&tsk->thread.fpu_state); | |
96 | fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE; | |
97 | fpu_state_owner = NULL; | |
98 | } | |
278d91c4 | 99 | #endif /* !CONFIG_LAZY_SAVE_FPU */ |
b920de1b DH |
100 | |
101 | preempt_enable(); | |
102 | ||
103 | /* we no longer have a valid current FPU state */ | |
104 | clear_using_fpu(tsk); | |
105 | ||
106 | /* transfer the saved FPU state onto the userspace stack */ | |
107 | if (copy_to_user(fpucontext, | |
108 | &tsk->thread.fpu_state, | |
109 | min(sizeof(struct fpu_state_struct), | |
110 | sizeof(struct fpucontext)))) | |
111 | return -1; | |
112 | ||
113 | return 1; | |
b920de1b DH |
114 | } |
115 | ||
116 | /* | |
117 | * kill a process's FPU state during restoration after signal handling | |
118 | */ | |
119 | void fpu_kill_state(struct task_struct *tsk) | |
120 | { | |
b920de1b DH |
121 | /* disown anything left in the FPU */ |
122 | preempt_disable(); | |
123 | ||
278d91c4 AT |
124 | #ifndef CONFIG_LAZY_SAVE_FPU |
125 | if (tsk->thread.fpu_flags & THREAD_HAS_FPU) { | |
126 | tsk->thread.uregs->epsw &= ~EPSW_FE; | |
127 | tsk->thread.fpu_flags &= ~THREAD_HAS_FPU; | |
128 | } | |
129 | #else /* !CONFIG_LAZY_SAVE_FPU */ | |
b920de1b DH |
130 | if (fpu_state_owner == tsk) { |
131 | fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE; | |
132 | fpu_state_owner = NULL; | |
133 | } | |
278d91c4 | 134 | #endif /* !CONFIG_LAZY_SAVE_FPU */ |
b920de1b DH |
135 | |
136 | preempt_enable(); | |
278d91c4 | 137 | |
b920de1b DH |
138 | /* we no longer have a valid current FPU state */ |
139 | clear_using_fpu(tsk); | |
140 | } | |
141 | ||
142 | /* | |
143 | * restore the FPU state from a signal context | |
144 | */ | |
145 | int fpu_restore_sigcontext(struct fpucontext *fpucontext) | |
146 | { | |
147 | struct task_struct *tsk = current; | |
148 | int ret; | |
149 | ||
150 | /* load up the old FPU state */ | |
278d91c4 | 151 | ret = copy_from_user(&tsk->thread.fpu_state, fpucontext, |
b920de1b DH |
152 | min(sizeof(struct fpu_state_struct), |
153 | sizeof(struct fpucontext))); | |
154 | if (!ret) | |
155 | set_using_fpu(tsk); | |
156 | ||
157 | return ret; | |
158 | } | |
159 | ||
160 | /* | |
161 | * fill in the FPU structure for a core dump | |
162 | */ | |
163 | int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpreg) | |
164 | { | |
165 | struct task_struct *tsk = current; | |
166 | int fpvalid; | |
167 | ||
168 | fpvalid = is_using_fpu(tsk); | |
169 | if (fpvalid) { | |
170 | unlazy_fpu(tsk); | |
171 | memcpy(fpreg, &tsk->thread.fpu_state, sizeof(*fpreg)); | |
172 | } | |
173 | ||
174 | return fpvalid; | |
175 | } |