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867e359b CM |
1 | /* |
2 | * Copyright (C) 1991, 1992 Linus Torvalds | |
3 | * Copyright 2010 Tilera Corporation. All Rights Reserved. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation, version 2. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, but | |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
12 | * NON INFRINGEMENT. See the GNU General Public License for | |
13 | * more details. | |
14 | */ | |
15 | ||
16 | #include <linux/sched.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/smp.h> | |
19 | #include <linux/smp_lock.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/signal.h> | |
22 | #include <linux/errno.h> | |
23 | #include <linux/wait.h> | |
24 | #include <linux/unistd.h> | |
25 | #include <linux/stddef.h> | |
26 | #include <linux/personality.h> | |
27 | #include <linux/suspend.h> | |
28 | #include <linux/ptrace.h> | |
29 | #include <linux/elf.h> | |
30 | #include <linux/compat.h> | |
31 | #include <linux/syscalls.h> | |
32 | #include <linux/uaccess.h> | |
33 | #include <asm/processor.h> | |
34 | #include <asm/ucontext.h> | |
35 | #include <asm/sigframe.h> | |
0707ad30 | 36 | #include <asm/syscalls.h> |
867e359b CM |
37 | #include <arch/interrupts.h> |
38 | ||
39 | #define DEBUG_SIG 0 | |
40 | ||
41 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
42 | ||
43 | ||
139ef32b | 44 | long _sys_sigaltstack(const stack_t __user *uss, |
0707ad30 | 45 | stack_t __user *uoss, struct pt_regs *regs) |
867e359b CM |
46 | { |
47 | return do_sigaltstack(uss, uoss, regs->sp); | |
48 | } | |
49 | ||
50 | ||
51 | /* | |
52 | * Do a signal return; undo the signal stack. | |
53 | */ | |
54 | ||
55 | int restore_sigcontext(struct pt_regs *regs, | |
56 | struct sigcontext __user *sc, long *pr0) | |
57 | { | |
58 | int err = 0; | |
59 | int i; | |
60 | ||
61 | /* Always make any pending restarted system calls return -EINTR */ | |
62 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
63 | ||
74fca9da CM |
64 | /* |
65 | * Enforce that sigcontext is like pt_regs, and doesn't mess | |
66 | * up our stack alignment rules. | |
67 | */ | |
68 | BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs)); | |
69 | BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0); | |
70 | ||
867e359b | 71 | for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) |
74fca9da | 72 | err |= __get_user(regs->regs[i], &sc->gregs[i]); |
867e359b CM |
73 | |
74 | regs->faultnum = INT_SWINT_1_SIGRETURN; | |
75 | ||
74fca9da | 76 | err |= __get_user(*pr0, &sc->gregs[0]); |
867e359b CM |
77 | return err; |
78 | } | |
79 | ||
0707ad30 CM |
80 | /* sigreturn() returns long since it restores r0 in the interrupted code. */ |
81 | long _sys_rt_sigreturn(struct pt_regs *regs) | |
867e359b CM |
82 | { |
83 | struct rt_sigframe __user *frame = | |
84 | (struct rt_sigframe __user *)(regs->sp); | |
85 | sigset_t set; | |
86 | long r0; | |
87 | ||
88 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
89 | goto badframe; | |
90 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
91 | goto badframe; | |
92 | ||
93 | sigdelsetmask(&set, ~_BLOCKABLE); | |
94 | spin_lock_irq(¤t->sighand->siglock); | |
95 | current->blocked = set; | |
96 | recalc_sigpending(); | |
97 | spin_unlock_irq(¤t->sighand->siglock); | |
98 | ||
99 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) | |
100 | goto badframe; | |
101 | ||
102 | if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT) | |
103 | goto badframe; | |
104 | ||
105 | return r0; | |
106 | ||
107 | badframe: | |
108 | force_sig(SIGSEGV, current); | |
109 | return 0; | |
110 | } | |
111 | ||
112 | /* | |
113 | * Set up a signal frame. | |
114 | */ | |
115 | ||
116 | int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) | |
117 | { | |
118 | int i, err = 0; | |
119 | ||
120 | for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) | |
74fca9da | 121 | err |= __put_user(regs->regs[i], &sc->gregs[i]); |
867e359b CM |
122 | |
123 | return err; | |
124 | } | |
125 | ||
126 | /* | |
127 | * Determine which stack to use.. | |
128 | */ | |
129 | static inline void __user *get_sigframe(struct k_sigaction *ka, | |
130 | struct pt_regs *regs, | |
131 | size_t frame_size) | |
132 | { | |
133 | unsigned long sp; | |
134 | ||
135 | /* Default to using normal stack */ | |
136 | sp = regs->sp; | |
137 | ||
138 | /* | |
139 | * If we are on the alternate signal stack and would overflow | |
140 | * it, don't. Return an always-bogus address instead so we | |
141 | * will die with SIGSEGV. | |
142 | */ | |
143 | if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size))) | |
0707ad30 | 144 | return (void __user __force *)-1UL; |
867e359b CM |
145 | |
146 | /* This is the X/Open sanctioned signal stack switching. */ | |
147 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
148 | if (sas_ss_flags(sp) == 0) | |
149 | sp = current->sas_ss_sp + current->sas_ss_size; | |
150 | } | |
151 | ||
152 | sp -= frame_size; | |
153 | /* | |
154 | * Align the stack pointer according to the TILE ABI, | |
155 | * i.e. so that on function entry (sp & 15) == 0. | |
156 | */ | |
157 | sp &= -16UL; | |
158 | return (void __user *) sp; | |
159 | } | |
160 | ||
161 | static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, | |
162 | sigset_t *set, struct pt_regs *regs) | |
163 | { | |
164 | unsigned long restorer; | |
165 | struct rt_sigframe __user *frame; | |
166 | int err = 0; | |
167 | int usig; | |
168 | ||
169 | frame = get_sigframe(ka, regs, sizeof(*frame)); | |
170 | ||
171 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
172 | goto give_sigsegv; | |
173 | ||
174 | usig = current_thread_info()->exec_domain | |
175 | && current_thread_info()->exec_domain->signal_invmap | |
176 | && sig < 32 | |
177 | ? current_thread_info()->exec_domain->signal_invmap[sig] | |
178 | : sig; | |
179 | ||
180 | /* Always write at least the signal number for the stack backtracer. */ | |
181 | if (ka->sa.sa_flags & SA_SIGINFO) { | |
182 | /* At sigreturn time, restore the callee-save registers too. */ | |
183 | err |= copy_siginfo_to_user(&frame->info, info); | |
184 | regs->flags |= PT_FLAGS_RESTORE_REGS; | |
185 | } else { | |
186 | err |= __put_user(info->si_signo, &frame->info.si_signo); | |
187 | } | |
188 | ||
189 | /* Create the ucontext. */ | |
190 | err |= __clear_user(&frame->save_area, sizeof(frame->save_area)); | |
191 | err |= __put_user(0, &frame->uc.uc_flags); | |
0707ad30 CM |
192 | err |= __put_user(NULL, &frame->uc.uc_link); |
193 | err |= __put_user((void __user *)(current->sas_ss_sp), | |
867e359b CM |
194 | &frame->uc.uc_stack.ss_sp); |
195 | err |= __put_user(sas_ss_flags(regs->sp), | |
196 | &frame->uc.uc_stack.ss_flags); | |
197 | err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
198 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); | |
199 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
200 | if (err) | |
201 | goto give_sigsegv; | |
202 | ||
203 | restorer = VDSO_BASE; | |
204 | if (ka->sa.sa_flags & SA_RESTORER) | |
205 | restorer = (unsigned long) ka->sa.sa_restorer; | |
206 | ||
207 | /* | |
208 | * Set up registers for signal handler. | |
209 | * Registers that we don't modify keep the value they had from | |
210 | * user-space at the time we took the signal. | |
74fca9da CM |
211 | * We always pass siginfo and mcontext, regardless of SA_SIGINFO, |
212 | * since some things rely on this (e.g. glibc's debug/segfault.c). | |
867e359b CM |
213 | */ |
214 | regs->pc = (unsigned long) ka->sa.sa_handler; | |
215 | regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */ | |
216 | regs->sp = (unsigned long) frame; | |
217 | regs->lr = restorer; | |
218 | regs->regs[0] = (unsigned long) usig; | |
74fca9da CM |
219 | regs->regs[1] = (unsigned long) &frame->info; |
220 | regs->regs[2] = (unsigned long) &frame->uc; | |
221 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
867e359b CM |
222 | |
223 | /* | |
224 | * Notify any tracer that was single-stepping it. | |
225 | * The tracer may want to single-step inside the | |
226 | * handler too. | |
227 | */ | |
228 | if (test_thread_flag(TIF_SINGLESTEP)) | |
229 | ptrace_notify(SIGTRAP); | |
230 | ||
231 | return 0; | |
232 | ||
233 | give_sigsegv: | |
234 | force_sigsegv(sig, current); | |
235 | return -EFAULT; | |
236 | } | |
237 | ||
238 | /* | |
239 | * OK, we're invoking a handler | |
240 | */ | |
241 | ||
242 | static int handle_signal(unsigned long sig, siginfo_t *info, | |
243 | struct k_sigaction *ka, sigset_t *oldset, | |
244 | struct pt_regs *regs) | |
245 | { | |
246 | int ret; | |
247 | ||
248 | ||
249 | /* Are we from a system call? */ | |
250 | if (regs->faultnum == INT_SWINT_1) { | |
251 | /* If so, check system call restarting.. */ | |
252 | switch (regs->regs[0]) { | |
253 | case -ERESTART_RESTARTBLOCK: | |
254 | case -ERESTARTNOHAND: | |
255 | regs->regs[0] = -EINTR; | |
256 | break; | |
257 | ||
258 | case -ERESTARTSYS: | |
259 | if (!(ka->sa.sa_flags & SA_RESTART)) { | |
260 | regs->regs[0] = -EINTR; | |
261 | break; | |
262 | } | |
263 | /* fallthrough */ | |
264 | case -ERESTARTNOINTR: | |
265 | /* Reload caller-saves to restore r0..r5 and r10. */ | |
266 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
267 | regs->regs[0] = regs->orig_r0; | |
268 | regs->pc -= 8; | |
269 | } | |
270 | } | |
271 | ||
272 | /* Set up the stack frame */ | |
273 | #ifdef CONFIG_COMPAT | |
274 | if (is_compat_task()) | |
275 | ret = compat_setup_rt_frame(sig, ka, info, oldset, regs); | |
276 | else | |
277 | #endif | |
278 | ret = setup_rt_frame(sig, ka, info, oldset, regs); | |
279 | if (ret == 0) { | |
280 | /* This code is only called from system calls or from | |
281 | * the work_pending path in the return-to-user code, and | |
282 | * either way we can re-enable interrupts unconditionally. | |
283 | */ | |
284 | spin_lock_irq(¤t->sighand->siglock); | |
285 | sigorsets(¤t->blocked, | |
286 | ¤t->blocked, &ka->sa.sa_mask); | |
287 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
288 | sigaddset(¤t->blocked, sig); | |
289 | recalc_sigpending(); | |
290 | spin_unlock_irq(¤t->sighand->siglock); | |
291 | } | |
292 | ||
293 | return ret; | |
294 | } | |
295 | ||
296 | /* | |
297 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
298 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
299 | * mistake. | |
300 | */ | |
301 | void do_signal(struct pt_regs *regs) | |
302 | { | |
303 | siginfo_t info; | |
304 | int signr; | |
305 | struct k_sigaction ka; | |
306 | sigset_t *oldset; | |
307 | ||
308 | /* | |
309 | * i386 will check if we're coming from kernel mode and bail out | |
310 | * here. In my experience this just turns weird crashes into | |
311 | * weird spin-hangs. But if we find a case where this seems | |
312 | * helpful, we can reinstate the check on "!user_mode(regs)". | |
313 | */ | |
314 | ||
315 | if (current_thread_info()->status & TS_RESTORE_SIGMASK) | |
316 | oldset = ¤t->saved_sigmask; | |
317 | else | |
318 | oldset = ¤t->blocked; | |
319 | ||
320 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
321 | if (signr > 0) { | |
322 | /* Whee! Actually deliver the signal. */ | |
323 | if (handle_signal(signr, &info, &ka, oldset, regs) == 0) { | |
324 | /* | |
325 | * A signal was successfully delivered; the saved | |
326 | * sigmask will have been stored in the signal frame, | |
327 | * and will be restored by sigreturn, so we can simply | |
328 | * clear the TS_RESTORE_SIGMASK flag. | |
329 | */ | |
330 | current_thread_info()->status &= ~TS_RESTORE_SIGMASK; | |
331 | } | |
332 | ||
333 | return; | |
334 | } | |
335 | ||
336 | /* Did we come from a system call? */ | |
337 | if (regs->faultnum == INT_SWINT_1) { | |
338 | /* Restart the system call - no handlers present */ | |
339 | switch (regs->regs[0]) { | |
340 | case -ERESTARTNOHAND: | |
341 | case -ERESTARTSYS: | |
342 | case -ERESTARTNOINTR: | |
343 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
344 | regs->regs[0] = regs->orig_r0; | |
345 | regs->pc -= 8; | |
346 | break; | |
347 | ||
348 | case -ERESTART_RESTARTBLOCK: | |
349 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
350 | regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall; | |
351 | regs->pc -= 8; | |
352 | break; | |
353 | } | |
354 | } | |
355 | ||
356 | /* If there's no signal to deliver, just put the saved sigmask back. */ | |
357 | if (current_thread_info()->status & TS_RESTORE_SIGMASK) { | |
358 | current_thread_info()->status &= ~TS_RESTORE_SIGMASK; | |
359 | sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); | |
360 | } | |
361 | } |