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5f97f7f9 HS |
1 | /* |
2 | * Copyright (C) 2004-2006 Atmel Corporation | |
3 | * | |
4 | * Based on linux/arch/sh/kernel/signal.c | |
5 | * Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima | |
6 | * Copyright (C) 1991, 1992 Linus Torvalds | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/sched.h> | |
14 | #include <linux/mm.h> | |
15 | #include <linux/errno.h> | |
16 | #include <linux/ptrace.h> | |
17 | #include <linux/unistd.h> | |
733e5e4b | 18 | #include <linux/tracehook.h> |
5f97f7f9 HS |
19 | |
20 | #include <asm/uaccess.h> | |
21 | #include <asm/ucontext.h> | |
c80ce2d5 | 22 | #include <asm/syscalls.h> |
5f97f7f9 | 23 | |
5f97f7f9 HS |
24 | struct rt_sigframe |
25 | { | |
26 | struct siginfo info; | |
27 | struct ucontext uc; | |
28 | unsigned long retcode; | |
29 | }; | |
30 | ||
31 | static int | |
32 | restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) | |
33 | { | |
34 | int err = 0; | |
35 | ||
36 | #define COPY(x) err |= __get_user(regs->x, &sc->x) | |
37 | COPY(sr); | |
38 | COPY(pc); | |
39 | COPY(lr); | |
40 | COPY(sp); | |
41 | COPY(r12); | |
42 | COPY(r11); | |
43 | COPY(r10); | |
44 | COPY(r9); | |
45 | COPY(r8); | |
46 | COPY(r7); | |
47 | COPY(r6); | |
48 | COPY(r5); | |
49 | COPY(r4); | |
50 | COPY(r3); | |
51 | COPY(r2); | |
52 | COPY(r1); | |
53 | COPY(r0); | |
54 | #undef COPY | |
55 | ||
56 | /* | |
57 | * Don't allow anyone to pretend they're running in supervisor | |
58 | * mode or something... | |
59 | */ | |
60 | err |= !valid_user_regs(regs); | |
61 | ||
62 | return err; | |
63 | } | |
64 | ||
65 | ||
66 | asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) | |
67 | { | |
68 | struct rt_sigframe __user *frame; | |
69 | sigset_t set; | |
70 | ||
446cdd13 AV |
71 | /* Always make any pending restarted system calls return -EINTR */ |
72 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
73 | ||
5f97f7f9 HS |
74 | frame = (struct rt_sigframe __user *)regs->sp; |
75 | pr_debug("SIG return: frame = %p\n", frame); | |
76 | ||
77 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
78 | goto badframe; | |
79 | ||
80 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
81 | goto badframe; | |
82 | ||
49209590 | 83 | set_current_blocked(&set); |
5f97f7f9 HS |
84 | |
85 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
86 | goto badframe; | |
87 | ||
47880695 | 88 | if (restore_altstack(&frame->uc.uc_stack)) |
7c1b90a1 MK |
89 | goto badframe; |
90 | ||
5f97f7f9 HS |
91 | pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n", |
92 | regs->pc, regs->lr, regs->sp); | |
93 | ||
94 | return regs->r12; | |
95 | ||
96 | badframe: | |
97 | force_sig(SIGSEGV, current); | |
98 | return 0; | |
99 | } | |
100 | ||
101 | static int | |
102 | setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) | |
103 | { | |
104 | int err = 0; | |
105 | ||
106 | #define COPY(x) err |= __put_user(regs->x, &sc->x) | |
107 | COPY(sr); | |
108 | COPY(pc); | |
109 | COPY(lr); | |
110 | COPY(sp); | |
111 | COPY(r12); | |
112 | COPY(r11); | |
113 | COPY(r10); | |
114 | COPY(r9); | |
115 | COPY(r8); | |
116 | COPY(r7); | |
117 | COPY(r6); | |
118 | COPY(r5); | |
119 | COPY(r4); | |
120 | COPY(r3); | |
121 | COPY(r2); | |
122 | COPY(r1); | |
123 | COPY(r0); | |
124 | #undef COPY | |
125 | ||
126 | return err; | |
127 | } | |
128 | ||
129 | static inline void __user * | |
130 | get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) | |
131 | { | |
132 | unsigned long sp = regs->sp; | |
133 | ||
134 | if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) | |
135 | sp = current->sas_ss_sp + current->sas_ss_size; | |
136 | ||
137 | return (void __user *)((sp - framesize) & ~3); | |
138 | } | |
139 | ||
140 | static int | |
141 | setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, | |
142 | sigset_t *set, struct pt_regs *regs) | |
143 | { | |
144 | struct rt_sigframe __user *frame; | |
145 | int err = 0; | |
146 | ||
147 | frame = get_sigframe(ka, regs, sizeof(*frame)); | |
148 | err = -EFAULT; | |
149 | if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) | |
150 | goto out; | |
151 | ||
152 | /* | |
153 | * Set up the return code: | |
154 | * | |
155 | * mov r8, __NR_rt_sigreturn | |
156 | * scall | |
157 | * | |
158 | * Note: This will blow up since we're using a non-executable | |
159 | * stack. Better use SA_RESTORER. | |
160 | */ | |
161 | #if __NR_rt_sigreturn > 127 | |
162 | # error __NR_rt_sigreturn must be < 127 to fit in a short mov | |
163 | #endif | |
164 | err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20), | |
165 | &frame->retcode); | |
166 | ||
167 | err |= copy_siginfo_to_user(&frame->info, info); | |
168 | ||
169 | /* Set up the ucontext */ | |
170 | err |= __put_user(0, &frame->uc.uc_flags); | |
171 | err |= __put_user(NULL, &frame->uc.uc_link); | |
47880695 | 172 | err |= __save_altstack(&frame->uc.uc_stack, regs->sp); |
5f97f7f9 HS |
173 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); |
174 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
175 | ||
176 | if (err) | |
177 | goto out; | |
178 | ||
179 | regs->r12 = sig; | |
180 | regs->r11 = (unsigned long) &frame->info; | |
181 | regs->r10 = (unsigned long) &frame->uc; | |
182 | regs->sp = (unsigned long) frame; | |
183 | if (ka->sa.sa_flags & SA_RESTORER) | |
184 | regs->lr = (unsigned long)ka->sa.sa_restorer; | |
185 | else { | |
186 | printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n", | |
187 | current->comm, current->pid); | |
188 | regs->lr = (unsigned long) &frame->retcode; | |
189 | } | |
190 | ||
191 | pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n", | |
192 | current->comm, current->pid, sig, regs->sp, | |
193 | regs->pc, ka->sa.sa_handler, regs->lr); | |
194 | ||
195 | regs->pc = (unsigned long) ka->sa.sa_handler; | |
196 | ||
197 | out: | |
198 | return err; | |
199 | } | |
200 | ||
288ddad5 | 201 | static inline void setup_syscall_restart(struct pt_regs *regs) |
5f97f7f9 HS |
202 | { |
203 | if (regs->r12 == -ERESTART_RESTARTBLOCK) | |
204 | regs->r8 = __NR_restart_syscall; | |
205 | else | |
206 | regs->r12 = regs->r12_orig; | |
207 | regs->pc -= 2; | |
208 | } | |
209 | ||
210 | static inline void | |
211 | handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, | |
b7f9a11a | 212 | struct pt_regs *regs, int syscall) |
5f97f7f9 HS |
213 | { |
214 | int ret; | |
215 | ||
216 | /* | |
217 | * Set up the stack frame | |
218 | */ | |
b7f9a11a | 219 | ret = setup_rt_frame(sig, ka, info, sigmask_to_save(), regs); |
5f97f7f9 HS |
220 | |
221 | /* | |
222 | * Check that the resulting registers are sane | |
223 | */ | |
224 | ret |= !valid_user_regs(regs); | |
225 | ||
226 | /* | |
e1b1fd79 | 227 | * Block the signal if we were successful. |
5f97f7f9 | 228 | */ |
a610d6e6 AV |
229 | if (ret != 0) |
230 | force_sigsegv(sig, current); | |
231 | else | |
efee984c | 232 | signal_delivered(sig, info, ka, regs, 0); |
5f97f7f9 HS |
233 | } |
234 | ||
235 | /* | |
236 | * Note that 'init' is a special process: it doesn't get signals it | |
237 | * doesn't want to handle. Thus you cannot kill init even with a | |
238 | * SIGKILL even by mistake. | |
239 | */ | |
b7f9a11a | 240 | static void do_signal(struct pt_regs *regs, int syscall) |
5f97f7f9 HS |
241 | { |
242 | siginfo_t info; | |
243 | int signr; | |
244 | struct k_sigaction ka; | |
245 | ||
246 | /* | |
247 | * We want the common case to go fast, which is why we may in | |
248 | * certain cases get here from kernel mode. Just return | |
249 | * without doing anything if so. | |
250 | */ | |
251 | if (!user_mode(regs)) | |
b7f9a11a | 252 | return; |
5f97f7f9 HS |
253 | |
254 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
5f97f7f9 HS |
255 | if (syscall) { |
256 | switch (regs->r12) { | |
257 | case -ERESTART_RESTARTBLOCK: | |
258 | case -ERESTARTNOHAND: | |
259 | if (signr > 0) { | |
260 | regs->r12 = -EINTR; | |
261 | break; | |
262 | } | |
263 | /* fall through */ | |
264 | case -ERESTARTSYS: | |
265 | if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) { | |
266 | regs->r12 = -EINTR; | |
267 | break; | |
268 | } | |
269 | /* fall through */ | |
270 | case -ERESTARTNOINTR: | |
288ddad5 | 271 | setup_syscall_restart(regs); |
5f97f7f9 HS |
272 | } |
273 | } | |
274 | ||
275 | if (signr == 0) { | |
276 | /* No signal to deliver -- put the saved sigmask back */ | |
51a7b448 | 277 | restore_saved_sigmask(); |
b7f9a11a | 278 | return; |
5f97f7f9 HS |
279 | } |
280 | ||
b7f9a11a | 281 | handle_signal(signr, &ka, &info, regs, syscall); |
5f97f7f9 HS |
282 | } |
283 | ||
284 | asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti) | |
285 | { | |
286 | int syscall = 0; | |
287 | ||
288 | if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR) | |
289 | syscall = 1; | |
290 | ||
03240b27 | 291 | if (ti->flags & _TIF_SIGPENDING) |
b7f9a11a | 292 | do_signal(regs, syscall); |
d0420c83 DH |
293 | |
294 | if (ti->flags & _TIF_NOTIFY_RESUME) { | |
295 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
296 | tracehook_notify_resume(regs); | |
297 | } | |
5f97f7f9 | 298 | } |