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