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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm26/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1995-2002 Russell King | |
5 | * Copyright (C) 2003 Ian Molton (ARM26) | |
6 | * | |
7 | * FIXME!!! This is probably very broken (13/05/2003) | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | */ | |
13 | #include <linux/config.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/smp_lock.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/errno.h> | |
20 | #include <linux/signal.h> | |
21 | #include <linux/wait.h> | |
22 | #include <linux/ptrace.h> | |
23 | #include <linux/personality.h> | |
24 | #include <linux/tty.h> | |
25 | #include <linux/binfmts.h> | |
26 | #include <linux/elf.h> | |
27 | ||
28 | #include <asm/pgalloc.h> | |
29 | #include <asm/ucontext.h> | |
30 | #include <asm/uaccess.h> | |
31 | #include <asm/unistd.h> | |
32 | ||
33 | #include "ptrace.h" | |
34 | ||
35 | #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) | |
36 | ||
37 | /* | |
38 | * For ARM syscalls, we encode the syscall number into the instruction. | |
39 | */ | |
40 | #define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)) | |
41 | #define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)) | |
42 | ||
43 | static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall); | |
44 | ||
45 | /* | |
46 | * atomically swap in the new signal mask, and wait for a signal. | |
47 | */ | |
48 | asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs) | |
49 | { | |
50 | sigset_t saveset; | |
51 | ||
52 | mask &= _BLOCKABLE; | |
53 | spin_lock_irq(¤t->sighand->siglock); | |
54 | saveset = current->blocked; | |
55 | siginitset(¤t->blocked, mask); | |
56 | recalc_sigpending(); | |
57 | spin_unlock_irq(¤t->sighand->siglock); | |
58 | regs->ARM_r0 = -EINTR; | |
59 | ||
60 | while (1) { | |
61 | current->state = TASK_INTERRUPTIBLE; | |
62 | schedule(); | |
63 | if (do_signal(&saveset, regs, 0)) | |
64 | return regs->ARM_r0; | |
65 | } | |
66 | } | |
67 | ||
68 | asmlinkage int | |
69 | sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, struct pt_regs *regs) | |
70 | { | |
71 | sigset_t saveset, newset; | |
72 | ||
73 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
74 | if (sigsetsize != sizeof(sigset_t)) | |
75 | return -EINVAL; | |
76 | ||
77 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
78 | return -EFAULT; | |
79 | sigdelsetmask(&newset, ~_BLOCKABLE); | |
80 | ||
81 | spin_lock_irq(¤t->sighand->siglock); | |
82 | saveset = current->blocked; | |
83 | current->blocked = newset; | |
84 | recalc_sigpending(); | |
85 | spin_unlock_irq(¤t->sighand->siglock); | |
86 | regs->ARM_r0 = -EINTR; | |
87 | ||
88 | while (1) { | |
89 | current->state = TASK_INTERRUPTIBLE; | |
90 | schedule(); | |
91 | if (do_signal(&saveset, regs, 0)) | |
92 | return regs->ARM_r0; | |
93 | } | |
94 | } | |
95 | ||
96 | asmlinkage int | |
97 | sys_sigaction(int sig, const struct old_sigaction *act, | |
98 | struct old_sigaction *oact) | |
99 | { | |
100 | struct k_sigaction new_ka, old_ka; | |
101 | int ret; | |
102 | ||
103 | if (act) { | |
104 | old_sigset_t mask; | |
105 | if (!access_ok(VERIFY_READ, act, sizeof(*act)) || | |
106 | __get_user(new_ka.sa.sa_handler, &act->sa_handler) || | |
107 | __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) | |
108 | return -EFAULT; | |
109 | __get_user(new_ka.sa.sa_flags, &act->sa_flags); | |
110 | __get_user(mask, &act->sa_mask); | |
111 | siginitset(&new_ka.sa.sa_mask, mask); | |
112 | } | |
113 | ||
114 | ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); | |
115 | ||
116 | if (!ret && oact) { | |
117 | if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || | |
118 | __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || | |
119 | __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) | |
120 | return -EFAULT; | |
121 | __put_user(old_ka.sa.sa_flags, &oact->sa_flags); | |
122 | __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); | |
123 | } | |
124 | ||
125 | return ret; | |
126 | } | |
127 | ||
128 | /* | |
129 | * Do a signal return; undo the signal stack. | |
130 | */ | |
131 | struct sigframe | |
132 | { | |
133 | struct sigcontext sc; | |
134 | unsigned long extramask[_NSIG_WORDS-1]; | |
135 | unsigned long retcode; | |
136 | }; | |
137 | ||
138 | struct rt_sigframe | |
139 | { | |
140 | struct siginfo *pinfo; | |
141 | void *puc; | |
142 | struct siginfo info; | |
143 | struct ucontext uc; | |
144 | unsigned long retcode; | |
145 | }; | |
146 | ||
147 | static int | |
148 | restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc) | |
149 | { | |
150 | int err = 0; | |
151 | ||
152 | __get_user_error(regs->ARM_r0, &sc->arm_r0, err); | |
153 | __get_user_error(regs->ARM_r1, &sc->arm_r1, err); | |
154 | __get_user_error(regs->ARM_r2, &sc->arm_r2, err); | |
155 | __get_user_error(regs->ARM_r3, &sc->arm_r3, err); | |
156 | __get_user_error(regs->ARM_r4, &sc->arm_r4, err); | |
157 | __get_user_error(regs->ARM_r5, &sc->arm_r5, err); | |
158 | __get_user_error(regs->ARM_r6, &sc->arm_r6, err); | |
159 | __get_user_error(regs->ARM_r7, &sc->arm_r7, err); | |
160 | __get_user_error(regs->ARM_r8, &sc->arm_r8, err); | |
161 | __get_user_error(regs->ARM_r9, &sc->arm_r9, err); | |
162 | __get_user_error(regs->ARM_r10, &sc->arm_r10, err); | |
163 | __get_user_error(regs->ARM_fp, &sc->arm_fp, err); | |
164 | __get_user_error(regs->ARM_ip, &sc->arm_ip, err); | |
165 | __get_user_error(regs->ARM_sp, &sc->arm_sp, err); | |
166 | __get_user_error(regs->ARM_lr, &sc->arm_lr, err); | |
167 | __get_user_error(regs->ARM_pc, &sc->arm_pc, err); | |
168 | ||
169 | err |= !valid_user_regs(regs); | |
170 | ||
171 | return err; | |
172 | } | |
173 | ||
174 | asmlinkage int sys_sigreturn(struct pt_regs *regs) | |
175 | { | |
176 | struct sigframe *frame; | |
177 | sigset_t set; | |
178 | ||
179 | /* | |
180 | * Since we stacked the signal on a 64-bit boundary, | |
181 | * then 'sp' should be word aligned here. If it's | |
182 | * not, then the user is trying to mess with us. | |
183 | */ | |
184 | if (regs->ARM_sp & 7) | |
185 | goto badframe; | |
186 | ||
187 | frame = (struct sigframe *)regs->ARM_sp; | |
188 | ||
189 | if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) | |
190 | goto badframe; | |
191 | if (__get_user(set.sig[0], &frame->sc.oldmask) | |
192 | || (_NSIG_WORDS > 1 | |
193 | && __copy_from_user(&set.sig[1], &frame->extramask, | |
194 | sizeof(frame->extramask)))) | |
195 | goto badframe; | |
196 | ||
197 | sigdelsetmask(&set, ~_BLOCKABLE); | |
198 | spin_lock_irq(¤t->sighand->siglock); | |
199 | current->blocked = set; | |
200 | recalc_sigpending(); | |
201 | spin_unlock_irq(¤t->sighand->siglock); | |
202 | ||
203 | if (restore_sigcontext(regs, &frame->sc)) | |
204 | goto badframe; | |
205 | ||
206 | /* Send SIGTRAP if we're single-stepping */ | |
207 | if (current->ptrace & PT_SINGLESTEP) { | |
208 | ptrace_cancel_bpt(current); | |
209 | send_sig(SIGTRAP, current, 1); | |
210 | } | |
211 | ||
212 | return regs->ARM_r0; | |
213 | ||
214 | badframe: | |
215 | force_sig(SIGSEGV, current); | |
216 | return 0; | |
217 | } | |
218 | ||
219 | asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) | |
220 | { | |
221 | struct rt_sigframe *frame; | |
222 | sigset_t set; | |
223 | ||
224 | /* | |
225 | * Since we stacked the signal on a 64-bit boundary, | |
226 | * then 'sp' should be word aligned here. If it's | |
227 | * not, then the user is trying to mess with us. | |
228 | */ | |
229 | if (regs->ARM_sp & 7) | |
230 | goto badframe; | |
231 | ||
232 | frame = (struct rt_sigframe *)regs->ARM_sp; | |
233 | ||
234 | if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) | |
235 | goto badframe; | |
236 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
237 | goto badframe; | |
238 | ||
239 | sigdelsetmask(&set, ~_BLOCKABLE); | |
240 | spin_lock_irq(¤t->sighand->siglock); | |
241 | current->blocked = set; | |
242 | recalc_sigpending(); | |
243 | spin_unlock_irq(¤t->sighand->siglock); | |
244 | ||
245 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
246 | goto badframe; | |
247 | ||
248 | /* Send SIGTRAP if we're single-stepping */ | |
249 | if (current->ptrace & PT_SINGLESTEP) { | |
250 | ptrace_cancel_bpt(current); | |
251 | send_sig(SIGTRAP, current, 1); | |
252 | } | |
253 | ||
254 | return regs->ARM_r0; | |
255 | ||
256 | badframe: | |
257 | force_sig(SIGSEGV, current); | |
258 | return 0; | |
259 | } | |
260 | ||
261 | static int | |
262 | setup_sigcontext(struct sigcontext *sc, /*struct _fpstate *fpstate,*/ | |
263 | struct pt_regs *regs, unsigned long mask) | |
264 | { | |
265 | int err = 0; | |
266 | ||
267 | __put_user_error(regs->ARM_r0, &sc->arm_r0, err); | |
268 | __put_user_error(regs->ARM_r1, &sc->arm_r1, err); | |
269 | __put_user_error(regs->ARM_r2, &sc->arm_r2, err); | |
270 | __put_user_error(regs->ARM_r3, &sc->arm_r3, err); | |
271 | __put_user_error(regs->ARM_r4, &sc->arm_r4, err); | |
272 | __put_user_error(regs->ARM_r5, &sc->arm_r5, err); | |
273 | __put_user_error(regs->ARM_r6, &sc->arm_r6, err); | |
274 | __put_user_error(regs->ARM_r7, &sc->arm_r7, err); | |
275 | __put_user_error(regs->ARM_r8, &sc->arm_r8, err); | |
276 | __put_user_error(regs->ARM_r9, &sc->arm_r9, err); | |
277 | __put_user_error(regs->ARM_r10, &sc->arm_r10, err); | |
278 | __put_user_error(regs->ARM_fp, &sc->arm_fp, err); | |
279 | __put_user_error(regs->ARM_ip, &sc->arm_ip, err); | |
280 | __put_user_error(regs->ARM_sp, &sc->arm_sp, err); | |
281 | __put_user_error(regs->ARM_lr, &sc->arm_lr, err); | |
282 | __put_user_error(regs->ARM_pc, &sc->arm_pc, err); | |
283 | ||
284 | __put_user_error(current->thread.trap_no, &sc->trap_no, err); | |
285 | __put_user_error(current->thread.error_code, &sc->error_code, err); | |
286 | __put_user_error(current->thread.address, &sc->fault_address, err); | |
287 | __put_user_error(mask, &sc->oldmask, err); | |
288 | ||
289 | return err; | |
290 | } | |
291 | ||
292 | static inline void * | |
293 | get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) | |
294 | { | |
295 | unsigned long sp = regs->ARM_sp; | |
296 | ||
297 | /* | |
298 | * This is the X/Open sanctioned signal stack switching. | |
299 | */ | |
300 | if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) | |
301 | sp = current->sas_ss_sp + current->sas_ss_size; | |
302 | ||
303 | /* | |
304 | * ATPCS B01 mandates 8-byte alignment | |
305 | */ | |
306 | return (void *)((sp - framesize) & ~7); | |
307 | } | |
308 | ||
309 | static int | |
310 | setup_return(struct pt_regs *regs, struct k_sigaction *ka, | |
311 | unsigned long *rc, void *frame, int usig) | |
312 | { | |
313 | unsigned long handler = (unsigned long)ka->sa.sa_handler; | |
314 | unsigned long retcode; | |
315 | ||
316 | if (ka->sa.sa_flags & SA_RESTORER) { | |
317 | retcode = (unsigned long)ka->sa.sa_restorer; | |
318 | } else { | |
319 | ||
320 | if (__put_user((ka->sa.sa_flags & SA_SIGINFO)?SWI_SYS_RT_SIGRETURN:SWI_SYS_SIGRETURN, rc)) | |
321 | return 1; | |
322 | ||
323 | retcode = ((unsigned long)rc); | |
324 | } | |
325 | ||
326 | regs->ARM_r0 = usig; | |
327 | regs->ARM_sp = (unsigned long)frame; | |
328 | regs->ARM_lr = retcode; | |
329 | regs->ARM_pc = handler & ~3; | |
330 | ||
331 | return 0; | |
332 | } | |
333 | ||
334 | static int | |
335 | setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) | |
336 | { | |
337 | struct sigframe *frame = get_sigframe(ka, regs, sizeof(*frame)); | |
338 | int err = 0; | |
339 | ||
340 | if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) | |
341 | return 1; | |
342 | ||
343 | err |= setup_sigcontext(&frame->sc, /*&frame->fpstate,*/ regs, set->sig[0]); | |
344 | ||
345 | if (_NSIG_WORDS > 1) { | |
346 | err |= __copy_to_user(frame->extramask, &set->sig[1], | |
347 | sizeof(frame->extramask)); | |
348 | } | |
349 | ||
350 | if (err == 0) | |
351 | err = setup_return(regs, ka, &frame->retcode, frame, usig); | |
352 | ||
353 | return err; | |
354 | } | |
355 | ||
356 | static int | |
357 | setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, | |
358 | sigset_t *set, struct pt_regs *regs) | |
359 | { | |
360 | struct rt_sigframe *frame = get_sigframe(ka, regs, sizeof(*frame)); | |
361 | int err = 0; | |
362 | ||
363 | if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) | |
364 | return 1; | |
365 | ||
366 | __put_user_error(&frame->info, &frame->pinfo, err); | |
367 | __put_user_error(&frame->uc, &frame->puc, err); | |
368 | err |= copy_siginfo_to_user(&frame->info, info); | |
369 | ||
370 | /* Clear all the bits of the ucontext we don't use. */ | |
371 | err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext)); | |
372 | ||
373 | err |= setup_sigcontext(&frame->uc.uc_mcontext, /*&frame->fpstate,*/ | |
374 | regs, set->sig[0]); | |
375 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
376 | ||
377 | if (err == 0) | |
378 | err = setup_return(regs, ka, &frame->retcode, frame, usig); | |
379 | ||
380 | if (err == 0) { | |
381 | /* | |
382 | * For realtime signals we must also set the second and third | |
383 | * arguments for the signal handler. | |
384 | * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 | |
385 | */ | |
386 | regs->ARM_r1 = (unsigned long)frame->pinfo; | |
387 | regs->ARM_r2 = (unsigned long)frame->puc; | |
388 | } | |
389 | ||
390 | return err; | |
391 | } | |
392 | ||
393 | static inline void restart_syscall(struct pt_regs *regs) | |
394 | { | |
395 | regs->ARM_r0 = regs->ARM_ORIG_r0; | |
396 | regs->ARM_pc -= 4; | |
397 | } | |
398 | ||
399 | /* | |
400 | * OK, we're invoking a handler | |
401 | */ | |
402 | static void | |
403 | handle_signal(unsigned long sig, siginfo_t *info, sigset_t *oldset, | |
404 | struct pt_regs * regs, int syscall) | |
405 | { | |
406 | struct thread_info *thread = current_thread_info(); | |
407 | struct task_struct *tsk = current; | |
408 | struct k_sigaction *ka = &tsk->sighand->action[sig-1]; | |
409 | int usig = sig; | |
410 | int ret; | |
411 | ||
412 | /* | |
413 | * If we were from a system call, check for system call restarting... | |
414 | */ | |
415 | if (syscall) { | |
416 | switch (regs->ARM_r0) { | |
417 | case -ERESTART_RESTARTBLOCK: | |
418 | current_thread_info()->restart_block.fn = | |
419 | do_no_restart_syscall; | |
420 | case -ERESTARTNOHAND: | |
421 | regs->ARM_r0 = -EINTR; | |
422 | break; | |
423 | case -ERESTARTSYS: | |
424 | if (!(ka->sa.sa_flags & SA_RESTART)) { | |
425 | regs->ARM_r0 = -EINTR; | |
426 | break; | |
427 | } | |
428 | /* fallthrough */ | |
429 | case -ERESTARTNOINTR: | |
430 | restart_syscall(regs); | |
431 | } | |
432 | } | |
433 | ||
434 | /* | |
435 | * translate the signal | |
436 | */ | |
437 | if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) | |
438 | usig = thread->exec_domain->signal_invmap[usig]; | |
439 | ||
440 | /* | |
441 | * Set up the stack frame | |
442 | */ | |
443 | if (ka->sa.sa_flags & SA_SIGINFO) | |
444 | ret = setup_rt_frame(usig, ka, info, oldset, regs); | |
445 | else | |
446 | ret = setup_frame(usig, ka, oldset, regs); | |
447 | ||
448 | /* | |
449 | * Check that the resulting registers are actually sane. | |
450 | */ | |
451 | ret |= !valid_user_regs(regs); | |
452 | ||
453 | if (ret == 0) { | |
454 | if (ka->sa.sa_flags & SA_ONESHOT) | |
455 | ka->sa.sa_handler = SIG_DFL; | |
456 | ||
69be8f18 SR |
457 | spin_lock_irq(&tsk->sighand->siglock); |
458 | sigorsets(&tsk->blocked, &tsk->blocked, | |
459 | &ka->sa.sa_mask); | |
460 | if (!(ka->sa.sa_flags & SA_NODEFER)) | |
1da177e4 | 461 | sigaddset(&tsk->blocked, sig); |
69be8f18 SR |
462 | recalc_sigpending(); |
463 | spin_unlock_irq(&tsk->sighand->siglock); | |
1da177e4 LT |
464 | return; |
465 | } | |
466 | ||
467 | force_sigsegv(sig, tsk); | |
468 | } | |
469 | ||
470 | /* | |
471 | * Note that 'init' is a special process: it doesn't get signals it doesn't | |
472 | * want to handle. Thus you cannot kill init even with a SIGKILL even by | |
473 | * mistake. | |
474 | * | |
475 | * Note that we go through the signals twice: once to check the signals that | |
476 | * the kernel can handle, and then we build all the user-level signal handling | |
477 | * stack-frames in one go after that. | |
478 | */ | |
479 | static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) | |
480 | { | |
481 | siginfo_t info; | |
482 | int signr; | |
483 | ||
484 | /* | |
485 | * We want the common case to go fast, which | |
486 | * is why we may in certain cases get here from | |
487 | * kernel mode. Just return without doing anything | |
488 | * if so. | |
489 | */ | |
490 | if (!user_mode(regs)) | |
491 | return 0; | |
492 | ||
493 | if (current->ptrace & PT_SINGLESTEP) | |
494 | ptrace_cancel_bpt(current); | |
495 | ||
496 | signr = get_signal_to_deliver(&info, regs, NULL); | |
497 | if (signr > 0) { | |
498 | handle_signal(signr, &info, oldset, regs, syscall); | |
499 | if (current->ptrace & PT_SINGLESTEP) | |
500 | ptrace_set_bpt(current); | |
501 | return 1; | |
502 | } | |
503 | ||
504 | /* | |
505 | * No signal to deliver to the process - restart the syscall. | |
506 | */ | |
507 | if (syscall) { | |
508 | if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) { | |
509 | u32 *usp; | |
510 | ||
511 | regs->ARM_sp -= 12; | |
512 | usp = (u32 *)regs->ARM_sp; | |
513 | ||
514 | put_user(regs->ARM_pc, &usp[0]); | |
515 | /* swi __NR_restart_syscall */ | |
516 | put_user(0xef000000 | __NR_restart_syscall, &usp[1]); | |
517 | /* ldr pc, [sp], #12 */ | |
518 | // FIXME!!! is #12 correct there? | |
519 | put_user(0xe49df00c, &usp[2]); | |
520 | ||
521 | regs->ARM_pc = regs->ARM_sp + 4; | |
522 | } | |
523 | if (regs->ARM_r0 == -ERESTARTNOHAND || | |
524 | regs->ARM_r0 == -ERESTARTSYS || | |
525 | regs->ARM_r0 == -ERESTARTNOINTR) { | |
526 | restart_syscall(regs); | |
527 | } | |
528 | } | |
529 | if (current->ptrace & PT_SINGLESTEP) | |
530 | ptrace_set_bpt(current); | |
531 | return 0; | |
532 | } | |
533 | ||
534 | asmlinkage void | |
535 | do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) | |
536 | { | |
537 | if (thread_flags & _TIF_SIGPENDING) | |
538 | do_signal(¤t->blocked, regs, syscall); | |
539 | } |