Commit | Line | Data |
---|---|---|
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> | |
867e359b CM |
19 | #include <linux/kernel.h> |
20 | #include <linux/signal.h> | |
21 | #include <linux/errno.h> | |
22 | #include <linux/wait.h> | |
23 | #include <linux/unistd.h> | |
24 | #include <linux/stddef.h> | |
25 | #include <linux/personality.h> | |
26 | #include <linux/suspend.h> | |
27 | #include <linux/ptrace.h> | |
28 | #include <linux/elf.h> | |
29 | #include <linux/compat.h> | |
30 | #include <linux/syscalls.h> | |
31 | #include <linux/uaccess.h> | |
32 | #include <asm/processor.h> | |
33 | #include <asm/ucontext.h> | |
34 | #include <asm/sigframe.h> | |
0707ad30 | 35 | #include <asm/syscalls.h> |
867e359b CM |
36 | #include <arch/interrupts.h> |
37 | ||
38 | #define DEBUG_SIG 0 | |
39 | ||
40 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
41 | ||
d929b6ae CM |
42 | SYSCALL_DEFINE3(sigaltstack, const stack_t __user *, uss, |
43 | stack_t __user *, uoss, struct pt_regs *, regs) | |
867e359b CM |
44 | { |
45 | return do_sigaltstack(uss, uoss, regs->sp); | |
46 | } | |
47 | ||
48 | ||
49 | /* | |
50 | * Do a signal return; undo the signal stack. | |
51 | */ | |
52 | ||
53 | int restore_sigcontext(struct pt_regs *regs, | |
81711cee | 54 | struct sigcontext __user *sc) |
867e359b CM |
55 | { |
56 | int err = 0; | |
57 | int i; | |
58 | ||
59 | /* Always make any pending restarted system calls return -EINTR */ | |
60 | current_thread_info()->restart_block.fn = do_no_restart_syscall; | |
61 | ||
74fca9da CM |
62 | /* |
63 | * Enforce that sigcontext is like pt_regs, and doesn't mess | |
64 | * up our stack alignment rules. | |
65 | */ | |
66 | BUILD_BUG_ON(sizeof(struct sigcontext) != sizeof(struct pt_regs)); | |
67 | BUILD_BUG_ON(sizeof(struct sigcontext) % 8 != 0); | |
68 | ||
867e359b | 69 | for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) |
74fca9da | 70 | err |= __get_user(regs->regs[i], &sc->gregs[i]); |
867e359b | 71 | |
1deb9c5d CM |
72 | /* Ensure that the PL is always set to USER_PL. */ |
73 | regs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(regs->ex1)); | |
74 | ||
867e359b CM |
75 | regs->faultnum = INT_SWINT_1_SIGRETURN; |
76 | ||
867e359b CM |
77 | return err; |
78 | } | |
79 | ||
571d76ac CM |
80 | void signal_fault(const char *type, struct pt_regs *regs, |
81 | void __user *frame, int sig) | |
82 | { | |
83 | trace_unhandled_signal(type, regs, (unsigned long)frame, SIGSEGV); | |
84 | force_sigsegv(sig, current); | |
85 | } | |
86 | ||
81711cee | 87 | /* The assembly shim for this function arranges to ignore the return value. */ |
d929b6ae | 88 | SYSCALL_DEFINE1(rt_sigreturn, struct pt_regs *, regs) |
867e359b CM |
89 | { |
90 | struct rt_sigframe __user *frame = | |
91 | (struct rt_sigframe __user *)(regs->sp); | |
92 | sigset_t set; | |
867e359b CM |
93 | |
94 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
95 | goto badframe; | |
96 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
97 | goto badframe; | |
98 | ||
99 | sigdelsetmask(&set, ~_BLOCKABLE); | |
100 | spin_lock_irq(¤t->sighand->siglock); | |
101 | current->blocked = set; | |
102 | recalc_sigpending(); | |
103 | spin_unlock_irq(¤t->sighand->siglock); | |
104 | ||
81711cee | 105 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) |
867e359b CM |
106 | goto badframe; |
107 | ||
108 | if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT) | |
109 | goto badframe; | |
110 | ||
81711cee | 111 | return 0; |
867e359b CM |
112 | |
113 | badframe: | |
571d76ac | 114 | signal_fault("bad sigreturn frame", regs, frame, 0); |
867e359b CM |
115 | return 0; |
116 | } | |
117 | ||
118 | /* | |
119 | * Set up a signal frame. | |
120 | */ | |
121 | ||
122 | int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) | |
123 | { | |
124 | int i, err = 0; | |
125 | ||
126 | for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i) | |
74fca9da | 127 | err |= __put_user(regs->regs[i], &sc->gregs[i]); |
867e359b CM |
128 | |
129 | return err; | |
130 | } | |
131 | ||
132 | /* | |
133 | * Determine which stack to use.. | |
134 | */ | |
135 | static inline void __user *get_sigframe(struct k_sigaction *ka, | |
136 | struct pt_regs *regs, | |
137 | size_t frame_size) | |
138 | { | |
139 | unsigned long sp; | |
140 | ||
141 | /* Default to using normal stack */ | |
142 | sp = regs->sp; | |
143 | ||
144 | /* | |
145 | * If we are on the alternate signal stack and would overflow | |
146 | * it, don't. Return an always-bogus address instead so we | |
147 | * will die with SIGSEGV. | |
148 | */ | |
149 | if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size))) | |
0707ad30 | 150 | return (void __user __force *)-1UL; |
867e359b CM |
151 | |
152 | /* This is the X/Open sanctioned signal stack switching. */ | |
153 | if (ka->sa.sa_flags & SA_ONSTACK) { | |
154 | if (sas_ss_flags(sp) == 0) | |
155 | sp = current->sas_ss_sp + current->sas_ss_size; | |
156 | } | |
157 | ||
158 | sp -= frame_size; | |
159 | /* | |
160 | * Align the stack pointer according to the TILE ABI, | |
161 | * i.e. so that on function entry (sp & 15) == 0. | |
162 | */ | |
163 | sp &= -16UL; | |
164 | return (void __user *) sp; | |
165 | } | |
166 | ||
167 | static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, | |
168 | sigset_t *set, struct pt_regs *regs) | |
169 | { | |
170 | unsigned long restorer; | |
171 | struct rt_sigframe __user *frame; | |
172 | int err = 0; | |
173 | int usig; | |
174 | ||
175 | frame = get_sigframe(ka, regs, sizeof(*frame)); | |
176 | ||
177 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) | |
178 | goto give_sigsegv; | |
179 | ||
180 | usig = current_thread_info()->exec_domain | |
181 | && current_thread_info()->exec_domain->signal_invmap | |
182 | && sig < 32 | |
183 | ? current_thread_info()->exec_domain->signal_invmap[sig] | |
184 | : sig; | |
185 | ||
186 | /* Always write at least the signal number for the stack backtracer. */ | |
187 | if (ka->sa.sa_flags & SA_SIGINFO) { | |
188 | /* At sigreturn time, restore the callee-save registers too. */ | |
189 | err |= copy_siginfo_to_user(&frame->info, info); | |
190 | regs->flags |= PT_FLAGS_RESTORE_REGS; | |
191 | } else { | |
192 | err |= __put_user(info->si_signo, &frame->info.si_signo); | |
193 | } | |
194 | ||
195 | /* Create the ucontext. */ | |
196 | err |= __clear_user(&frame->save_area, sizeof(frame->save_area)); | |
197 | err |= __put_user(0, &frame->uc.uc_flags); | |
0707ad30 CM |
198 | err |= __put_user(NULL, &frame->uc.uc_link); |
199 | err |= __put_user((void __user *)(current->sas_ss_sp), | |
867e359b CM |
200 | &frame->uc.uc_stack.ss_sp); |
201 | err |= __put_user(sas_ss_flags(regs->sp), | |
202 | &frame->uc.uc_stack.ss_flags); | |
203 | err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); | |
204 | err |= setup_sigcontext(&frame->uc.uc_mcontext, regs); | |
205 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
206 | if (err) | |
207 | goto give_sigsegv; | |
208 | ||
209 | restorer = VDSO_BASE; | |
210 | if (ka->sa.sa_flags & SA_RESTORER) | |
211 | restorer = (unsigned long) ka->sa.sa_restorer; | |
212 | ||
213 | /* | |
214 | * Set up registers for signal handler. | |
215 | * Registers that we don't modify keep the value they had from | |
216 | * user-space at the time we took the signal. | |
74fca9da CM |
217 | * We always pass siginfo and mcontext, regardless of SA_SIGINFO, |
218 | * since some things rely on this (e.g. glibc's debug/segfault.c). | |
867e359b CM |
219 | */ |
220 | regs->pc = (unsigned long) ka->sa.sa_handler; | |
221 | regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */ | |
222 | regs->sp = (unsigned long) frame; | |
223 | regs->lr = restorer; | |
224 | regs->regs[0] = (unsigned long) usig; | |
74fca9da CM |
225 | regs->regs[1] = (unsigned long) &frame->info; |
226 | regs->regs[2] = (unsigned long) &frame->uc; | |
227 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
867e359b CM |
228 | |
229 | /* | |
230 | * Notify any tracer that was single-stepping it. | |
231 | * The tracer may want to single-step inside the | |
232 | * handler too. | |
233 | */ | |
234 | if (test_thread_flag(TIF_SINGLESTEP)) | |
235 | ptrace_notify(SIGTRAP); | |
236 | ||
237 | return 0; | |
238 | ||
239 | give_sigsegv: | |
571d76ac | 240 | signal_fault("bad setup frame", regs, frame, sig); |
867e359b CM |
241 | return -EFAULT; |
242 | } | |
243 | ||
244 | /* | |
245 | * OK, we're invoking a handler | |
246 | */ | |
247 | ||
248 | static int handle_signal(unsigned long sig, siginfo_t *info, | |
249 | struct k_sigaction *ka, sigset_t *oldset, | |
250 | struct pt_regs *regs) | |
251 | { | |
252 | int ret; | |
253 | ||
867e359b CM |
254 | /* Are we from a system call? */ |
255 | if (regs->faultnum == INT_SWINT_1) { | |
256 | /* If so, check system call restarting.. */ | |
257 | switch (regs->regs[0]) { | |
258 | case -ERESTART_RESTARTBLOCK: | |
259 | case -ERESTARTNOHAND: | |
260 | regs->regs[0] = -EINTR; | |
261 | break; | |
262 | ||
263 | case -ERESTARTSYS: | |
264 | if (!(ka->sa.sa_flags & SA_RESTART)) { | |
265 | regs->regs[0] = -EINTR; | |
266 | break; | |
267 | } | |
268 | /* fallthrough */ | |
269 | case -ERESTARTNOINTR: | |
270 | /* Reload caller-saves to restore r0..r5 and r10. */ | |
271 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
272 | regs->regs[0] = regs->orig_r0; | |
273 | regs->pc -= 8; | |
274 | } | |
275 | } | |
276 | ||
277 | /* Set up the stack frame */ | |
278 | #ifdef CONFIG_COMPAT | |
279 | if (is_compat_task()) | |
280 | ret = compat_setup_rt_frame(sig, ka, info, oldset, regs); | |
281 | else | |
282 | #endif | |
283 | ret = setup_rt_frame(sig, ka, info, oldset, regs); | |
284 | if (ret == 0) { | |
285 | /* This code is only called from system calls or from | |
286 | * the work_pending path in the return-to-user code, and | |
287 | * either way we can re-enable interrupts unconditionally. | |
288 | */ | |
289 | spin_lock_irq(¤t->sighand->siglock); | |
290 | sigorsets(¤t->blocked, | |
291 | ¤t->blocked, &ka->sa.sa_mask); | |
292 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
293 | sigaddset(¤t->blocked, sig); | |
294 | recalc_sigpending(); | |
295 | spin_unlock_irq(¤t->sighand->siglock); | |
296 | } | |
297 | ||
298 | return ret; | |
299 | } | |
300 | ||
301 | /* | |
302 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
303 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
304 | * mistake. | |
305 | */ | |
306 | void do_signal(struct pt_regs *regs) | |
307 | { | |
308 | siginfo_t info; | |
309 | int signr; | |
310 | struct k_sigaction ka; | |
311 | sigset_t *oldset; | |
312 | ||
313 | /* | |
314 | * i386 will check if we're coming from kernel mode and bail out | |
315 | * here. In my experience this just turns weird crashes into | |
316 | * weird spin-hangs. But if we find a case where this seems | |
317 | * helpful, we can reinstate the check on "!user_mode(regs)". | |
318 | */ | |
319 | ||
320 | if (current_thread_info()->status & TS_RESTORE_SIGMASK) | |
321 | oldset = ¤t->saved_sigmask; | |
322 | else | |
323 | oldset = ¤t->blocked; | |
324 | ||
325 | signr = get_signal_to_deliver(&info, &ka, regs, NULL); | |
326 | if (signr > 0) { | |
327 | /* Whee! Actually deliver the signal. */ | |
328 | if (handle_signal(signr, &info, &ka, oldset, regs) == 0) { | |
329 | /* | |
330 | * A signal was successfully delivered; the saved | |
331 | * sigmask will have been stored in the signal frame, | |
332 | * and will be restored by sigreturn, so we can simply | |
333 | * clear the TS_RESTORE_SIGMASK flag. | |
334 | */ | |
335 | current_thread_info()->status &= ~TS_RESTORE_SIGMASK; | |
336 | } | |
337 | ||
34a89d26 | 338 | goto done; |
867e359b CM |
339 | } |
340 | ||
341 | /* Did we come from a system call? */ | |
342 | if (regs->faultnum == INT_SWINT_1) { | |
343 | /* Restart the system call - no handlers present */ | |
344 | switch (regs->regs[0]) { | |
345 | case -ERESTARTNOHAND: | |
346 | case -ERESTARTSYS: | |
347 | case -ERESTARTNOINTR: | |
348 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
349 | regs->regs[0] = regs->orig_r0; | |
350 | regs->pc -= 8; | |
351 | break; | |
352 | ||
353 | case -ERESTART_RESTARTBLOCK: | |
354 | regs->flags |= PT_FLAGS_CALLER_SAVES; | |
355 | regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall; | |
356 | regs->pc -= 8; | |
357 | break; | |
358 | } | |
359 | } | |
360 | ||
361 | /* If there's no signal to deliver, just put the saved sigmask back. */ | |
362 | if (current_thread_info()->status & TS_RESTORE_SIGMASK) { | |
363 | current_thread_info()->status &= ~TS_RESTORE_SIGMASK; | |
364 | sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); | |
365 | } | |
34a89d26 CM |
366 | |
367 | done: | |
368 | /* Avoid double syscall restart if there are nested signals. */ | |
369 | regs->faultnum = INT_SWINT_1_SIGRETURN; | |
867e359b | 370 | } |
571d76ac CM |
371 | |
372 | int show_unhandled_signals = 1; | |
373 | ||
374 | static int __init crashinfo(char *str) | |
375 | { | |
376 | unsigned long val; | |
377 | const char *word; | |
378 | ||
379 | if (*str == '\0') | |
380 | val = 2; | |
381 | else if (*str != '=' || strict_strtoul(++str, 0, &val) != 0) | |
382 | return 0; | |
383 | show_unhandled_signals = val; | |
384 | switch (show_unhandled_signals) { | |
385 | case 0: | |
386 | word = "No"; | |
387 | break; | |
388 | case 1: | |
389 | word = "One-line"; | |
390 | break; | |
391 | default: | |
392 | word = "Detailed"; | |
393 | break; | |
394 | } | |
395 | pr_info("%s crash reports will be generated on the console\n", word); | |
396 | return 1; | |
397 | } | |
398 | __setup("crashinfo", crashinfo); | |
399 | ||
400 | static void dump_mem(void __user *address) | |
401 | { | |
402 | void __user *addr; | |
403 | enum { region_size = 256, bytes_per_line = 16 }; | |
404 | int i, j, k; | |
405 | int found_readable_mem = 0; | |
406 | ||
407 | pr_err("\n"); | |
408 | if (!access_ok(VERIFY_READ, address, 1)) { | |
409 | pr_err("Not dumping at address 0x%lx (kernel address)\n", | |
410 | (unsigned long)address); | |
411 | return; | |
412 | } | |
413 | ||
414 | addr = (void __user *) | |
415 | (((unsigned long)address & -bytes_per_line) - region_size/2); | |
416 | if (addr > address) | |
417 | addr = NULL; | |
418 | for (i = 0; i < region_size; | |
419 | addr += bytes_per_line, i += bytes_per_line) { | |
420 | unsigned char buf[bytes_per_line]; | |
421 | char line[100]; | |
422 | if (copy_from_user(buf, addr, bytes_per_line)) | |
423 | continue; | |
424 | if (!found_readable_mem) { | |
425 | pr_err("Dumping memory around address 0x%lx:\n", | |
426 | (unsigned long)address); | |
427 | found_readable_mem = 1; | |
428 | } | |
429 | j = sprintf(line, REGFMT":", (unsigned long)addr); | |
430 | for (k = 0; k < bytes_per_line; ++k) | |
431 | j += sprintf(&line[j], " %02x", buf[k]); | |
432 | pr_err("%s\n", line); | |
433 | } | |
434 | if (!found_readable_mem) | |
435 | pr_err("No readable memory around address 0x%lx\n", | |
436 | (unsigned long)address); | |
437 | } | |
438 | ||
439 | void trace_unhandled_signal(const char *type, struct pt_regs *regs, | |
440 | unsigned long address, int sig) | |
441 | { | |
442 | struct task_struct *tsk = current; | |
443 | ||
444 | if (show_unhandled_signals == 0) | |
445 | return; | |
446 | ||
447 | /* If the signal is handled, don't show it here. */ | |
448 | if (!is_global_init(tsk)) { | |
449 | void __user *handler = | |
450 | tsk->sighand->action[sig-1].sa.sa_handler; | |
451 | if (handler != SIG_IGN && handler != SIG_DFL) | |
452 | return; | |
453 | } | |
454 | ||
455 | /* Rate-limit the one-line output, not the detailed output. */ | |
456 | if (show_unhandled_signals <= 1 && !printk_ratelimit()) | |
457 | return; | |
458 | ||
459 | printk("%s%s[%d]: %s at %lx pc "REGFMT" signal %d", | |
460 | task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, | |
461 | tsk->comm, task_pid_nr(tsk), type, address, regs->pc, sig); | |
462 | ||
463 | print_vma_addr(KERN_CONT " in ", regs->pc); | |
464 | ||
465 | printk(KERN_CONT "\n"); | |
466 | ||
467 | if (show_unhandled_signals > 1) { | |
468 | switch (sig) { | |
469 | case SIGILL: | |
470 | case SIGFPE: | |
471 | case SIGSEGV: | |
472 | case SIGBUS: | |
473 | pr_err("User crash: signal %d," | |
474 | " trap %ld, address 0x%lx\n", | |
475 | sig, regs->faultnum, address); | |
476 | show_regs(regs); | |
477 | dump_mem((void __user *)address); | |
478 | break; | |
479 | default: | |
480 | pr_err("User crash: signal %d, trap %ld\n", | |
481 | sig, regs->faultnum); | |
482 | break; | |
483 | } | |
484 | } | |
485 | } |