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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> | |
7dfb7103 | 18 | #include <linux/freezer.h> |
5f97f7f9 HS |
19 | |
20 | #include <asm/uaccess.h> | |
21 | #include <asm/ucontext.h> | |
c80ce2d5 | 22 | #include <asm/syscalls.h> |
5f97f7f9 HS |
23 | |
24 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
25 | ||
26 | asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, | |
27 | struct pt_regs *regs) | |
28 | { | |
29 | return do_sigaltstack(uss, uoss, regs->sp); | |
30 | } | |
31 | ||
32 | struct rt_sigframe | |
33 | { | |
34 | struct siginfo info; | |
35 | struct ucontext uc; | |
36 | unsigned long retcode; | |
37 | }; | |
38 | ||
39 | static int | |
40 | restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) | |
41 | { | |
42 | int err = 0; | |
43 | ||
44 | #define COPY(x) err |= __get_user(regs->x, &sc->x) | |
45 | COPY(sr); | |
46 | COPY(pc); | |
47 | COPY(lr); | |
48 | COPY(sp); | |
49 | COPY(r12); | |
50 | COPY(r11); | |
51 | COPY(r10); | |
52 | COPY(r9); | |
53 | COPY(r8); | |
54 | COPY(r7); | |
55 | COPY(r6); | |
56 | COPY(r5); | |
57 | COPY(r4); | |
58 | COPY(r3); | |
59 | COPY(r2); | |
60 | COPY(r1); | |
61 | COPY(r0); | |
62 | #undef COPY | |
63 | ||
64 | /* | |
65 | * Don't allow anyone to pretend they're running in supervisor | |
66 | * mode or something... | |
67 | */ | |
68 | err |= !valid_user_regs(regs); | |
69 | ||
70 | return err; | |
71 | } | |
72 | ||
73 | ||
74 | asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) | |
75 | { | |
76 | struct rt_sigframe __user *frame; | |
77 | sigset_t set; | |
78 | ||
79 | frame = (struct rt_sigframe __user *)regs->sp; | |
80 | pr_debug("SIG return: frame = %p\n", frame); | |
81 | ||
82 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
83 | goto badframe; | |
84 | ||
85 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
86 | goto badframe; | |
87 | ||
88 | sigdelsetmask(&set, ~_BLOCKABLE); | |
89 | spin_lock_irq(¤t->sighand->siglock); | |
90 | current->blocked = set; | |
91 | recalc_sigpending(); | |
92 | spin_unlock_irq(¤t->sighand->siglock); | |
93 | ||
94 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
95 | goto badframe; | |
96 | ||
7c1b90a1 MK |
97 | if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT) |
98 | goto badframe; | |
99 | ||
5f97f7f9 HS |
100 | pr_debug("Context restored: pc = %08lx, lr = %08lx, sp = %08lx\n", |
101 | regs->pc, regs->lr, regs->sp); | |
102 | ||
103 | return regs->r12; | |
104 | ||
105 | badframe: | |
106 | force_sig(SIGSEGV, current); | |
107 | return 0; | |
108 | } | |
109 | ||
110 | static int | |
111 | setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) | |
112 | { | |
113 | int err = 0; | |
114 | ||
115 | #define COPY(x) err |= __put_user(regs->x, &sc->x) | |
116 | COPY(sr); | |
117 | COPY(pc); | |
118 | COPY(lr); | |
119 | COPY(sp); | |
120 | COPY(r12); | |
121 | COPY(r11); | |
122 | COPY(r10); | |
123 | COPY(r9); | |
124 | COPY(r8); | |
125 | COPY(r7); | |
126 | COPY(r6); | |
127 | COPY(r5); | |
128 | COPY(r4); | |
129 | COPY(r3); | |
130 | COPY(r2); | |
131 | COPY(r1); | |
132 | COPY(r0); | |
133 | #undef COPY | |
134 | ||
135 | return err; | |
136 | } | |
137 | ||
138 | static inline void __user * | |
139 | get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) | |
140 | { | |
141 | unsigned long sp = regs->sp; | |
142 | ||
143 | if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) | |
144 | sp = current->sas_ss_sp + current->sas_ss_size; | |
145 | ||
146 | return (void __user *)((sp - framesize) & ~3); | |
147 | } | |
148 | ||
149 | static int | |
150 | setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, | |
151 | sigset_t *set, struct pt_regs *regs) | |
152 | { | |
153 | struct rt_sigframe __user *frame; | |
154 | int err = 0; | |
155 | ||
156 | frame = get_sigframe(ka, regs, sizeof(*frame)); | |
157 | err = -EFAULT; | |
158 | if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) | |
159 | goto out; | |
160 | ||
161 | /* | |
162 | * Set up the return code: | |
163 | * | |
164 | * mov r8, __NR_rt_sigreturn | |
165 | * scall | |
166 | * | |
167 | * Note: This will blow up since we're using a non-executable | |
168 | * stack. Better use SA_RESTORER. | |
169 | */ | |
170 | #if __NR_rt_sigreturn > 127 | |
171 | # error __NR_rt_sigreturn must be < 127 to fit in a short mov | |
172 | #endif | |
173 | err = __put_user(0x3008d733 | (__NR_rt_sigreturn << 20), | |
174 | &frame->retcode); | |
175 | ||
176 | err |= copy_siginfo_to_user(&frame->info, info); | |
177 | ||
178 | /* Set up the ucontext */ | |
179 | err |= __put_user(0, &frame->uc.uc_flags); | |
180 | err |= __put_user(NULL, &frame->uc.uc_link); | |
181 | err |= __put_user((void __user *)current->sas_ss_sp, | |
182 | &frame->uc.uc_stack.ss_sp); | |
183 | err |= __put_user(sas_ss_flags(regs->sp), | |
184 | &frame->uc.uc_stack.ss_flags); | |
185 | err |= __put_user(current->sas_ss_size, | |
186 | &frame->uc.uc_stack.ss_size); | |
187 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); | |
188 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
189 | ||
190 | if (err) | |
191 | goto out; | |
192 | ||
193 | regs->r12 = sig; | |
194 | regs->r11 = (unsigned long) &frame->info; | |
195 | regs->r10 = (unsigned long) &frame->uc; | |
196 | regs->sp = (unsigned long) frame; | |
197 | if (ka->sa.sa_flags & SA_RESTORER) | |
198 | regs->lr = (unsigned long)ka->sa.sa_restorer; | |
199 | else { | |
200 | printk(KERN_NOTICE "[%s:%d] did not set SA_RESTORER\n", | |
201 | current->comm, current->pid); | |
202 | regs->lr = (unsigned long) &frame->retcode; | |
203 | } | |
204 | ||
205 | pr_debug("SIG deliver [%s:%d]: sig=%d sp=0x%lx pc=0x%lx->0x%p lr=0x%lx\n", | |
206 | current->comm, current->pid, sig, regs->sp, | |
207 | regs->pc, ka->sa.sa_handler, regs->lr); | |
208 | ||
209 | regs->pc = (unsigned long) ka->sa.sa_handler; | |
210 | ||
211 | out: | |
212 | return err; | |
213 | } | |
214 | ||
288ddad5 | 215 | static inline void setup_syscall_restart(struct pt_regs *regs) |
5f97f7f9 HS |
216 | { |
217 | if (regs->r12 == -ERESTART_RESTARTBLOCK) | |
218 | regs->r8 = __NR_restart_syscall; | |
219 | else | |
220 | regs->r12 = regs->r12_orig; | |
221 | regs->pc -= 2; | |
222 | } | |
223 | ||
224 | static inline void | |
225 | handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, | |
226 | sigset_t *oldset, struct pt_regs *regs, int syscall) | |
227 | { | |
228 | int ret; | |
229 | ||
230 | /* | |
231 | * Set up the stack frame | |
232 | */ | |
233 | ret = setup_rt_frame(sig, ka, info, oldset, regs); | |
234 | ||
235 | /* | |
236 | * Check that the resulting registers are sane | |
237 | */ | |
238 | ret |= !valid_user_regs(regs); | |
239 | ||
240 | /* | |
241 | * Block the signal if we were unsuccessful. | |
242 | */ | |
243 | if (ret != 0 || !(ka->sa.sa_flags & SA_NODEFER)) { | |
244 | spin_lock_irq(¤t->sighand->siglock); | |
245 | sigorsets(¤t->blocked, ¤t->blocked, | |
246 | &ka->sa.sa_mask); | |
247 | sigaddset(¤t->blocked, sig); | |
248 | recalc_sigpending(); | |
249 | spin_unlock_irq(¤t->sighand->siglock); | |
250 | } | |
251 | ||
252 | if (ret == 0) | |
253 | return; | |
254 | ||
255 | force_sigsegv(sig, current); | |
256 | } | |
257 | ||
258 | /* | |
259 | * Note that 'init' is a special process: it doesn't get signals it | |
260 | * doesn't want to handle. Thus you cannot kill init even with a | |
261 | * SIGKILL even by mistake. | |
262 | */ | |
263 | int do_signal(struct pt_regs *regs, sigset_t *oldset, int syscall) | |
264 | { | |
265 | siginfo_t info; | |
266 | int signr; | |
267 | struct k_sigaction ka; | |
268 | ||
269 | /* | |
270 | * We want the common case to go fast, which is why we may in | |
271 | * certain cases get here from kernel mode. Just return | |
272 | * without doing anything if so. | |
273 | */ | |
274 | if (!user_mode(regs)) | |
275 | return 0; | |
276 | ||
5f97f7f9 HS |
277 | if (test_thread_flag(TIF_RESTORE_SIGMASK)) |
278 | oldset = ¤t->saved_sigmask; | |
279 | else if (!oldset) | |
280 | oldset = ¤t->blocked; | |
281 | ||
282 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
5f97f7f9 HS |
283 | if (syscall) { |
284 | switch (regs->r12) { | |
285 | case -ERESTART_RESTARTBLOCK: | |
286 | case -ERESTARTNOHAND: | |
287 | if (signr > 0) { | |
288 | regs->r12 = -EINTR; | |
289 | break; | |
290 | } | |
291 | /* fall through */ | |
292 | case -ERESTARTSYS: | |
293 | if (signr > 0 && !(ka.sa.sa_flags & SA_RESTART)) { | |
294 | regs->r12 = -EINTR; | |
295 | break; | |
296 | } | |
297 | /* fall through */ | |
298 | case -ERESTARTNOINTR: | |
288ddad5 | 299 | setup_syscall_restart(regs); |
5f97f7f9 HS |
300 | } |
301 | } | |
302 | ||
303 | if (signr == 0) { | |
304 | /* No signal to deliver -- put the saved sigmask back */ | |
305 | if (test_thread_flag(TIF_RESTORE_SIGMASK)) { | |
306 | clear_thread_flag(TIF_RESTORE_SIGMASK); | |
307 | sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); | |
308 | } | |
309 | return 0; | |
310 | } | |
311 | ||
312 | handle_signal(signr, &ka, &info, oldset, regs, syscall); | |
313 | return 1; | |
314 | } | |
315 | ||
316 | asmlinkage void do_notify_resume(struct pt_regs *regs, struct thread_info *ti) | |
317 | { | |
318 | int syscall = 0; | |
319 | ||
320 | if ((sysreg_read(SR) & MODE_MASK) == MODE_SUPERVISOR) | |
321 | syscall = 1; | |
322 | ||
323 | if (ti->flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)) | |
324 | do_signal(regs, ¤t->blocked, syscall); | |
325 | } |