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-rw-r--r--arch/arm/kernel/signal.c748
1 files changed, 748 insertions, 0 deletions
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
new file mode 100644
index 000000000000..931919fd5121
--- /dev/null
+++ b/arch/arm/kernel/signal.c
@@ -0,0 +1,748 @@
1/*
2 * linux/arch/arm/kernel/signal.c
3 *
4 * Copyright (C) 1995-2002 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/config.h>
11#include <linux/errno.h>
12#include <linux/signal.h>
13#include <linux/ptrace.h>
14#include <linux/personality.h>
15
16#include <asm/cacheflush.h>
17#include <asm/ucontext.h>
18#include <asm/uaccess.h>
19#include <asm/unistd.h>
20
21#include "ptrace.h"
22
23#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
24
25/*
26 * For ARM syscalls, we encode the syscall number into the instruction.
27 */
28#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn))
29#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn))
30
31/*
32 * For Thumb syscalls, we pass the syscall number via r7. We therefore
33 * need two 16-bit instructions.
34 */
35#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
36#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
37
38static const unsigned long retcodes[4] = {
39 SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
40 SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN
41};
42
43static 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 */
48asmlinkage 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(&current->sighand->siglock);
54 saveset = current->blocked;
55 siginitset(&current->blocked, mask);
56 recalc_sigpending();
57 spin_unlock_irq(&current->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
68asmlinkage int
69sys_rt_sigsuspend(sigset_t __user *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(&current->sighand->siglock);
82 saveset = current->blocked;
83 current->blocked = newset;
84 recalc_sigpending();
85 spin_unlock_irq(&current->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
96asmlinkage int
97sys_sigaction(int sig, const struct old_sigaction __user *act,
98 struct old_sigaction __user *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#ifdef CONFIG_IWMMXT
129
130/* iwmmxt_area is 0x98 bytes long, preceeded by 8 bytes of signature */
131#define IWMMXT_STORAGE_SIZE (0x98 + 8)
132#define IWMMXT_MAGIC0 0x12ef842a
133#define IWMMXT_MAGIC1 0x1c07ca71
134
135struct iwmmxt_sigframe {
136 unsigned long magic0;
137 unsigned long magic1;
138 unsigned long storage[0x98/4];
139};
140
141static int page_present(struct mm_struct *mm, void __user *uptr, int wr)
142{
143 unsigned long addr = (unsigned long)uptr;
144 pgd_t *pgd = pgd_offset(mm, addr);
145 if (pgd_present(*pgd)) {
146 pmd_t *pmd = pmd_offset(pgd, addr);
147 if (pmd_present(*pmd)) {
148 pte_t *pte = pte_offset_map(pmd, addr);
149 return (pte_present(*pte) && (!wr || pte_write(*pte)));
150 }
151 }
152 return 0;
153}
154
155static int copy_locked(void __user *uptr, void *kptr, size_t size, int write,
156 void (*copyfn)(void *, void __user *))
157{
158 unsigned char v, __user *userptr = uptr;
159 int err = 0;
160
161 do {
162 struct mm_struct *mm;
163
164 if (write) {
165 __put_user_error(0, userptr, err);
166 __put_user_error(0, userptr + size - 1, err);
167 } else {
168 __get_user_error(v, userptr, err);
169 __get_user_error(v, userptr + size - 1, err);
170 }
171
172 if (err)
173 break;
174
175 mm = current->mm;
176 spin_lock(&mm->page_table_lock);
177 if (page_present(mm, userptr, write) &&
178 page_present(mm, userptr + size - 1, write)) {
179 copyfn(kptr, uptr);
180 } else
181 err = 1;
182 spin_unlock(&mm->page_table_lock);
183 } while (err);
184
185 return err;
186}
187
188static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
189{
190 int err = 0;
191
192 /* the iWMMXt context must be 64 bit aligned */
193 WARN_ON((unsigned long)frame & 7);
194
195 __put_user_error(IWMMXT_MAGIC0, &frame->magic0, err);
196 __put_user_error(IWMMXT_MAGIC1, &frame->magic1, err);
197
198 /*
199 * iwmmxt_task_copy() doesn't check user permissions.
200 * Let's do a dummy write on the upper boundary to ensure
201 * access to user mem is OK all way up.
202 */
203 err |= copy_locked(&frame->storage, current_thread_info(),
204 sizeof(frame->storage), 1, iwmmxt_task_copy);
205 return err;
206}
207
208static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
209{
210 unsigned long magic0, magic1;
211 int err = 0;
212
213 /* the iWMMXt context is 64 bit aligned */
214 WARN_ON((unsigned long)frame & 7);
215
216 /*
217 * Validate iWMMXt context signature.
218 * Also, iwmmxt_task_restore() doesn't check user permissions.
219 * Let's do a dummy write on the upper boundary to ensure
220 * access to user mem is OK all way up.
221 */
222 __get_user_error(magic0, &frame->magic0, err);
223 __get_user_error(magic1, &frame->magic1, err);
224 if (!err && magic0 == IWMMXT_MAGIC0 && magic1 == IWMMXT_MAGIC1)
225 err = copy_locked(&frame->storage, current_thread_info(),
226 sizeof(frame->storage), 0, iwmmxt_task_restore);
227 return err;
228}
229
230#endif
231
232/*
233 * Auxiliary signal frame. This saves stuff like FP state.
234 * The layout of this structure is not part of the user ABI.
235 */
236struct aux_sigframe {
237#ifdef CONFIG_IWMMXT
238 struct iwmmxt_sigframe iwmmxt;
239#endif
240#ifdef CONFIG_VFP
241 union vfp_state vfp;
242#endif
243};
244
245/*
246 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
247 */
248struct sigframe {
249 struct sigcontext sc;
250 unsigned long extramask[_NSIG_WORDS-1];
251 unsigned long retcode;
252 struct aux_sigframe aux __attribute__((aligned(8)));
253};
254
255struct rt_sigframe {
256 struct siginfo __user *pinfo;
257 void __user *puc;
258 struct siginfo info;
259 struct ucontext uc;
260 unsigned long retcode;
261 struct aux_sigframe aux __attribute__((aligned(8)));
262};
263
264static int
265restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
266 struct aux_sigframe __user *aux)
267{
268 int err = 0;
269
270 __get_user_error(regs->ARM_r0, &sc->arm_r0, err);
271 __get_user_error(regs->ARM_r1, &sc->arm_r1, err);
272 __get_user_error(regs->ARM_r2, &sc->arm_r2, err);
273 __get_user_error(regs->ARM_r3, &sc->arm_r3, err);
274 __get_user_error(regs->ARM_r4, &sc->arm_r4, err);
275 __get_user_error(regs->ARM_r5, &sc->arm_r5, err);
276 __get_user_error(regs->ARM_r6, &sc->arm_r6, err);
277 __get_user_error(regs->ARM_r7, &sc->arm_r7, err);
278 __get_user_error(regs->ARM_r8, &sc->arm_r8, err);
279 __get_user_error(regs->ARM_r9, &sc->arm_r9, err);
280 __get_user_error(regs->ARM_r10, &sc->arm_r10, err);
281 __get_user_error(regs->ARM_fp, &sc->arm_fp, err);
282 __get_user_error(regs->ARM_ip, &sc->arm_ip, err);
283 __get_user_error(regs->ARM_sp, &sc->arm_sp, err);
284 __get_user_error(regs->ARM_lr, &sc->arm_lr, err);
285 __get_user_error(regs->ARM_pc, &sc->arm_pc, err);
286 __get_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
287
288 err |= !valid_user_regs(regs);
289
290#ifdef CONFIG_IWMMXT
291 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
292 err |= restore_iwmmxt_context(&aux->iwmmxt);
293#endif
294#ifdef CONFIG_VFP
295// if (err == 0)
296// err |= vfp_restore_state(&aux->vfp);
297#endif
298
299 return err;
300}
301
302asmlinkage int sys_sigreturn(struct pt_regs *regs)
303{
304 struct sigframe __user *frame;
305 sigset_t set;
306
307 /* Always make any pending restarted system calls return -EINTR */
308 current_thread_info()->restart_block.fn = do_no_restart_syscall;
309
310 /*
311 * Since we stacked the signal on a 64-bit boundary,
312 * then 'sp' should be word aligned here. If it's
313 * not, then the user is trying to mess with us.
314 */
315 if (regs->ARM_sp & 7)
316 goto badframe;
317
318 frame = (struct sigframe __user *)regs->ARM_sp;
319
320 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
321 goto badframe;
322 if (__get_user(set.sig[0], &frame->sc.oldmask)
323 || (_NSIG_WORDS > 1
324 && __copy_from_user(&set.sig[1], &frame->extramask,
325 sizeof(frame->extramask))))
326 goto badframe;
327
328 sigdelsetmask(&set, ~_BLOCKABLE);
329 spin_lock_irq(&current->sighand->siglock);
330 current->blocked = set;
331 recalc_sigpending();
332 spin_unlock_irq(&current->sighand->siglock);
333
334 if (restore_sigcontext(regs, &frame->sc, &frame->aux))
335 goto badframe;
336
337 /* Send SIGTRAP if we're single-stepping */
338 if (current->ptrace & PT_SINGLESTEP) {
339 ptrace_cancel_bpt(current);
340 send_sig(SIGTRAP, current, 1);
341 }
342
343 return regs->ARM_r0;
344
345badframe:
346 force_sig(SIGSEGV, current);
347 return 0;
348}
349
350asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
351{
352 struct rt_sigframe __user *frame;
353 sigset_t set;
354
355 /* Always make any pending restarted system calls return -EINTR */
356 current_thread_info()->restart_block.fn = do_no_restart_syscall;
357
358 /*
359 * Since we stacked the signal on a 64-bit boundary,
360 * then 'sp' should be word aligned here. If it's
361 * not, then the user is trying to mess with us.
362 */
363 if (regs->ARM_sp & 7)
364 goto badframe;
365
366 frame = (struct rt_sigframe __user *)regs->ARM_sp;
367
368 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
369 goto badframe;
370 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
371 goto badframe;
372
373 sigdelsetmask(&set, ~_BLOCKABLE);
374 spin_lock_irq(&current->sighand->siglock);
375 current->blocked = set;
376 recalc_sigpending();
377 spin_unlock_irq(&current->sighand->siglock);
378
379 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &frame->aux))
380 goto badframe;
381
382 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
383 goto badframe;
384
385 /* Send SIGTRAP if we're single-stepping */
386 if (current->ptrace & PT_SINGLESTEP) {
387 ptrace_cancel_bpt(current);
388 send_sig(SIGTRAP, current, 1);
389 }
390
391 return regs->ARM_r0;
392
393badframe:
394 force_sig(SIGSEGV, current);
395 return 0;
396}
397
398static int
399setup_sigcontext(struct sigcontext __user *sc, struct aux_sigframe __user *aux,
400 struct pt_regs *regs, unsigned long mask)
401{
402 int err = 0;
403
404 __put_user_error(regs->ARM_r0, &sc->arm_r0, err);
405 __put_user_error(regs->ARM_r1, &sc->arm_r1, err);
406 __put_user_error(regs->ARM_r2, &sc->arm_r2, err);
407 __put_user_error(regs->ARM_r3, &sc->arm_r3, err);
408 __put_user_error(regs->ARM_r4, &sc->arm_r4, err);
409 __put_user_error(regs->ARM_r5, &sc->arm_r5, err);
410 __put_user_error(regs->ARM_r6, &sc->arm_r6, err);
411 __put_user_error(regs->ARM_r7, &sc->arm_r7, err);
412 __put_user_error(regs->ARM_r8, &sc->arm_r8, err);
413 __put_user_error(regs->ARM_r9, &sc->arm_r9, err);
414 __put_user_error(regs->ARM_r10, &sc->arm_r10, err);
415 __put_user_error(regs->ARM_fp, &sc->arm_fp, err);
416 __put_user_error(regs->ARM_ip, &sc->arm_ip, err);
417 __put_user_error(regs->ARM_sp, &sc->arm_sp, err);
418 __put_user_error(regs->ARM_lr, &sc->arm_lr, err);
419 __put_user_error(regs->ARM_pc, &sc->arm_pc, err);
420 __put_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
421
422 __put_user_error(current->thread.trap_no, &sc->trap_no, err);
423 __put_user_error(current->thread.error_code, &sc->error_code, err);
424 __put_user_error(current->thread.address, &sc->fault_address, err);
425 __put_user_error(mask, &sc->oldmask, err);
426
427#ifdef CONFIG_IWMMXT
428 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
429 err |= preserve_iwmmxt_context(&aux->iwmmxt);
430#endif
431#ifdef CONFIG_VFP
432// if (err == 0)
433// err |= vfp_save_state(&aux->vfp);
434#endif
435
436 return err;
437}
438
439static inline void __user *
440get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
441{
442 unsigned long sp = regs->ARM_sp;
443 void __user *frame;
444
445 /*
446 * This is the X/Open sanctioned signal stack switching.
447 */
448 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
449 sp = current->sas_ss_sp + current->sas_ss_size;
450
451 /*
452 * ATPCS B01 mandates 8-byte alignment
453 */
454 frame = (void __user *)((sp - framesize) & ~7);
455
456 /*
457 * Check that we can actually write to the signal frame.
458 */
459 if (!access_ok(VERIFY_WRITE, frame, framesize))
460 frame = NULL;
461
462 return frame;
463}
464
465static int
466setup_return(struct pt_regs *regs, struct k_sigaction *ka,
467 unsigned long __user *rc, void __user *frame, int usig)
468{
469 unsigned long handler = (unsigned long)ka->sa.sa_handler;
470 unsigned long retcode;
471 int thumb = 0;
472 unsigned long cpsr = regs->ARM_cpsr & ~PSR_f;
473
474 /*
475 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
476 */
477 if (ka->sa.sa_flags & SA_THIRTYTWO)
478 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
479
480#ifdef CONFIG_ARM_THUMB
481 if (elf_hwcap & HWCAP_THUMB) {
482 /*
483 * The LSB of the handler determines if we're going to
484 * be using THUMB or ARM mode for this signal handler.
485 */
486 thumb = handler & 1;
487
488 if (thumb)
489 cpsr |= PSR_T_BIT;
490 else
491 cpsr &= ~PSR_T_BIT;
492 }
493#endif
494
495 if (ka->sa.sa_flags & SA_RESTORER) {
496 retcode = (unsigned long)ka->sa.sa_restorer;
497 } else {
498 unsigned int idx = thumb;
499
500 if (ka->sa.sa_flags & SA_SIGINFO)
501 idx += 2;
502
503 if (__put_user(retcodes[idx], rc))
504 return 1;
505
506 /*
507 * Ensure that the instruction cache sees
508 * the return code written onto the stack.
509 */
510 flush_icache_range((unsigned long)rc,
511 (unsigned long)(rc + 1));
512
513 retcode = ((unsigned long)rc) + thumb;
514 }
515
516 regs->ARM_r0 = usig;
517 regs->ARM_sp = (unsigned long)frame;
518 regs->ARM_lr = retcode;
519 regs->ARM_pc = handler;
520 regs->ARM_cpsr = cpsr;
521
522 return 0;
523}
524
525static int
526setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
527{
528 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
529 int err = 0;
530
531 if (!frame)
532 return 1;
533
534 err |= setup_sigcontext(&frame->sc, &frame->aux, regs, set->sig[0]);
535
536 if (_NSIG_WORDS > 1) {
537 err |= __copy_to_user(frame->extramask, &set->sig[1],
538 sizeof(frame->extramask));
539 }
540
541 if (err == 0)
542 err = setup_return(regs, ka, &frame->retcode, frame, usig);
543
544 return err;
545}
546
547static int
548setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
549 sigset_t *set, struct pt_regs *regs)
550{
551 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
552 stack_t stack;
553 int err = 0;
554
555 if (!frame)
556 return 1;
557
558 __put_user_error(&frame->info, &frame->pinfo, err);
559 __put_user_error(&frame->uc, &frame->puc, err);
560 err |= copy_siginfo_to_user(&frame->info, info);
561
562 __put_user_error(0, &frame->uc.uc_flags, err);
563 __put_user_error(NULL, &frame->uc.uc_link, err);
564
565 memset(&stack, 0, sizeof(stack));
566 stack.ss_sp = (void __user *)current->sas_ss_sp;
567 stack.ss_flags = sas_ss_flags(regs->ARM_sp);
568 stack.ss_size = current->sas_ss_size;
569 err |= __copy_to_user(&frame->uc.uc_stack, &stack, sizeof(stack));
570
571 err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->aux,
572 regs, set->sig[0]);
573 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
574
575 if (err == 0)
576 err = setup_return(regs, ka, &frame->retcode, frame, usig);
577
578 if (err == 0) {
579 /*
580 * For realtime signals we must also set the second and third
581 * arguments for the signal handler.
582 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
583 */
584 regs->ARM_r1 = (unsigned long)&frame->info;
585 regs->ARM_r2 = (unsigned long)&frame->uc;
586 }
587
588 return err;
589}
590
591static inline void restart_syscall(struct pt_regs *regs)
592{
593 regs->ARM_r0 = regs->ARM_ORIG_r0;
594 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
595}
596
597/*
598 * OK, we're invoking a handler
599 */
600static void
601handle_signal(unsigned long sig, struct k_sigaction *ka,
602 siginfo_t *info, sigset_t *oldset,
603 struct pt_regs * regs, int syscall)
604{
605 struct thread_info *thread = current_thread_info();
606 struct task_struct *tsk = current;
607 int usig = sig;
608 int ret;
609
610 /*
611 * If we were from a system call, check for system call restarting...
612 */
613 if (syscall) {
614 switch (regs->ARM_r0) {
615 case -ERESTART_RESTARTBLOCK:
616 case -ERESTARTNOHAND:
617 regs->ARM_r0 = -EINTR;
618 break;
619 case -ERESTARTSYS:
620 if (!(ka->sa.sa_flags & SA_RESTART)) {
621 regs->ARM_r0 = -EINTR;
622 break;
623 }
624 /* fallthrough */
625 case -ERESTARTNOINTR:
626 restart_syscall(regs);
627 }
628 }
629
630 /*
631 * translate the signal
632 */
633 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
634 usig = thread->exec_domain->signal_invmap[usig];
635
636 /*
637 * Set up the stack frame
638 */
639 if (ka->sa.sa_flags & SA_SIGINFO)
640 ret = setup_rt_frame(usig, ka, info, oldset, regs);
641 else
642 ret = setup_frame(usig, ka, oldset, regs);
643
644 /*
645 * Check that the resulting registers are actually sane.
646 */
647 ret |= !valid_user_regs(regs);
648
649 /*
650 * Block the signal if we were unsuccessful.
651 */
652 if (ret != 0 || !(ka->sa.sa_flags & SA_NODEFER)) {
653 spin_lock_irq(&tsk->sighand->siglock);
654 sigorsets(&tsk->blocked, &tsk->blocked,
655 &ka->sa.sa_mask);
656 sigaddset(&tsk->blocked, sig);
657 recalc_sigpending();
658 spin_unlock_irq(&tsk->sighand->siglock);
659 }
660
661 if (ret == 0)
662 return;
663
664 force_sigsegv(sig, tsk);
665}
666
667/*
668 * Note that 'init' is a special process: it doesn't get signals it doesn't
669 * want to handle. Thus you cannot kill init even with a SIGKILL even by
670 * mistake.
671 *
672 * Note that we go through the signals twice: once to check the signals that
673 * the kernel can handle, and then we build all the user-level signal handling
674 * stack-frames in one go after that.
675 */
676static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
677{
678 struct k_sigaction ka;
679 siginfo_t info;
680 int signr;
681
682 /*
683 * We want the common case to go fast, which
684 * is why we may in certain cases get here from
685 * kernel mode. Just return without doing anything
686 * if so.
687 */
688 if (!user_mode(regs))
689 return 0;
690
691 if (try_to_freeze(0))
692 goto no_signal;
693
694 if (current->ptrace & PT_SINGLESTEP)
695 ptrace_cancel_bpt(current);
696
697 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
698 if (signr > 0) {
699 handle_signal(signr, &ka, &info, oldset, regs, syscall);
700 if (current->ptrace & PT_SINGLESTEP)
701 ptrace_set_bpt(current);
702 return 1;
703 }
704
705 no_signal:
706 /*
707 * No signal to deliver to the process - restart the syscall.
708 */
709 if (syscall) {
710 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
711 if (thumb_mode(regs)) {
712 regs->ARM_r7 = __NR_restart_syscall;
713 regs->ARM_pc -= 2;
714 } else {
715 u32 __user *usp;
716
717 regs->ARM_sp -= 12;
718 usp = (u32 __user *)regs->ARM_sp;
719
720 put_user(regs->ARM_pc, &usp[0]);
721 /* swi __NR_restart_syscall */
722 put_user(0xef000000 | __NR_restart_syscall, &usp[1]);
723 /* ldr pc, [sp], #12 */
724 put_user(0xe49df00c, &usp[2]);
725
726 flush_icache_range((unsigned long)usp,
727 (unsigned long)(usp + 3));
728
729 regs->ARM_pc = regs->ARM_sp + 4;
730 }
731 }
732 if (regs->ARM_r0 == -ERESTARTNOHAND ||
733 regs->ARM_r0 == -ERESTARTSYS ||
734 regs->ARM_r0 == -ERESTARTNOINTR) {
735 restart_syscall(regs);
736 }
737 }
738 if (current->ptrace & PT_SINGLESTEP)
739 ptrace_set_bpt(current);
740 return 0;
741}
742
743asmlinkage void
744do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
745{
746 if (thread_flags & _TIF_SIGPENDING)
747 do_signal(&current->blocked, regs, syscall);
748}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-24 00:25:01 -0500