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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/signal.c
4 *
5 * Copyright (C) 1995-2009 Russell King
6 */
7#include <linux/errno.h>
8#include <linux/random.h>
9#include <linux/signal.h>
10#include <linux/personality.h>
11#include <linux/uaccess.h>
12#include <linux/tracehook.h>
13#include <linux/uprobes.h>
14#include <linux/syscalls.h>
15
16#include <asm/elf.h>
17#include <asm/cacheflush.h>
18#include <asm/traps.h>
19#include <asm/unistd.h>
20#include <asm/vfp.h>
21
22#include "signal.h"
23
24extern const unsigned long sigreturn_codes[17];
25
26static unsigned long signal_return_offset;
27
28#ifdef CONFIG_CRUNCH
29static int preserve_crunch_context(struct crunch_sigframe __user *frame)
30{
31 char kbuf[sizeof(*frame) + 8];
32 struct crunch_sigframe *kframe;
33
34 /* the crunch context must be 64 bit aligned */
35 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
36 kframe->magic = CRUNCH_MAGIC;
37 kframe->size = CRUNCH_STORAGE_SIZE;
38 crunch_task_copy(current_thread_info(), &kframe->storage);
39 return __copy_to_user(frame, kframe, sizeof(*frame));
40}
41
42static int restore_crunch_context(char __user **auxp)
43{
44 struct crunch_sigframe __user *frame =
45 (struct crunch_sigframe __user *)*auxp;
46 char kbuf[sizeof(*frame) + 8];
47 struct crunch_sigframe *kframe;
48
49 /* the crunch context must be 64 bit aligned */
50 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
51 if (__copy_from_user(kframe, frame, sizeof(*frame)))
52 return -1;
53 if (kframe->magic != CRUNCH_MAGIC ||
54 kframe->size != CRUNCH_STORAGE_SIZE)
55 return -1;
56 *auxp += CRUNCH_STORAGE_SIZE;
57 crunch_task_restore(current_thread_info(), &kframe->storage);
58 return 0;
59}
60#endif
61
62#ifdef CONFIG_IWMMXT
63
64static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
65{
66 char kbuf[sizeof(*frame) + 8];
67 struct iwmmxt_sigframe *kframe;
68 int err = 0;
69
70 /* the iWMMXt context must be 64 bit aligned */
71 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
72
73 if (test_thread_flag(TIF_USING_IWMMXT)) {
74 kframe->magic = IWMMXT_MAGIC;
75 kframe->size = IWMMXT_STORAGE_SIZE;
76 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
77 } else {
78 /*
79 * For bug-compatibility with older kernels, some space
80 * has to be reserved for iWMMXt even if it's not used.
81 * Set the magic and size appropriately so that properly
82 * written userspace can skip it reliably:
83 */
84 *kframe = (struct iwmmxt_sigframe) {
85 .magic = DUMMY_MAGIC,
86 .size = IWMMXT_STORAGE_SIZE,
87 };
88 }
89
90 err = __copy_to_user(frame, kframe, sizeof(*kframe));
91
92 return err;
93}
94
95static int restore_iwmmxt_context(char __user **auxp)
96{
97 struct iwmmxt_sigframe __user *frame =
98 (struct iwmmxt_sigframe __user *)*auxp;
99 char kbuf[sizeof(*frame) + 8];
100 struct iwmmxt_sigframe *kframe;
101
102 /* the iWMMXt context must be 64 bit aligned */
103 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
104 if (__copy_from_user(kframe, frame, sizeof(*frame)))
105 return -1;
106
107 /*
108 * For non-iWMMXt threads: a single iwmmxt_sigframe-sized dummy
109 * block is discarded for compatibility with setup_sigframe() if
110 * present, but we don't mandate its presence. If some other
111 * magic is here, it's not for us:
112 */
113 if (!test_thread_flag(TIF_USING_IWMMXT) &&
114 kframe->magic != DUMMY_MAGIC)
115 return 0;
116
117 if (kframe->size != IWMMXT_STORAGE_SIZE)
118 return -1;
119
120 if (test_thread_flag(TIF_USING_IWMMXT)) {
121 if (kframe->magic != IWMMXT_MAGIC)
122 return -1;
123
124 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
125 }
126
127 *auxp += IWMMXT_STORAGE_SIZE;
128 return 0;
129}
130
131#endif
132
133#ifdef CONFIG_VFP
134
135static int preserve_vfp_context(struct vfp_sigframe __user *frame)
136{
137 struct vfp_sigframe kframe;
138 int err = 0;
139
140 memset(&kframe, 0, sizeof(kframe));
141 kframe.magic = VFP_MAGIC;
142 kframe.size = VFP_STORAGE_SIZE;
143
144 err = vfp_preserve_user_clear_hwstate(&kframe.ufp, &kframe.ufp_exc);
145 if (err)
146 return err;
147
148 return __copy_to_user(frame, &kframe, sizeof(kframe));
149}
150
151static int restore_vfp_context(char __user **auxp)
152{
153 struct vfp_sigframe frame;
154 int err;
155
156 err = __copy_from_user(&frame, *auxp, sizeof(frame));
157 if (err)
158 return err;
159
160 if (frame.magic != VFP_MAGIC || frame.size != VFP_STORAGE_SIZE)
161 return -EINVAL;
162
163 *auxp += sizeof(frame);
164 return vfp_restore_user_hwstate(&frame.ufp, &frame.ufp_exc);
165}
166
167#endif
168
169/*
170 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
171 */
172
173static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
174{
175 struct sigcontext context;
176 char __user *aux;
177 sigset_t set;
178 int err;
179
180 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
181 if (err == 0)
182 set_current_blocked(&set);
183
184 err |= __copy_from_user(&context, &sf->uc.uc_mcontext, sizeof(context));
185 if (err == 0) {
186 regs->ARM_r0 = context.arm_r0;
187 regs->ARM_r1 = context.arm_r1;
188 regs->ARM_r2 = context.arm_r2;
189 regs->ARM_r3 = context.arm_r3;
190 regs->ARM_r4 = context.arm_r4;
191 regs->ARM_r5 = context.arm_r5;
192 regs->ARM_r6 = context.arm_r6;
193 regs->ARM_r7 = context.arm_r7;
194 regs->ARM_r8 = context.arm_r8;
195 regs->ARM_r9 = context.arm_r9;
196 regs->ARM_r10 = context.arm_r10;
197 regs->ARM_fp = context.arm_fp;
198 regs->ARM_ip = context.arm_ip;
199 regs->ARM_sp = context.arm_sp;
200 regs->ARM_lr = context.arm_lr;
201 regs->ARM_pc = context.arm_pc;
202 regs->ARM_cpsr = context.arm_cpsr;
203 }
204
205 err |= !valid_user_regs(regs);
206
207 aux = (char __user *) sf->uc.uc_regspace;
208#ifdef CONFIG_CRUNCH
209 if (err == 0)
210 err |= restore_crunch_context(&aux);
211#endif
212#ifdef CONFIG_IWMMXT
213 if (err == 0)
214 err |= restore_iwmmxt_context(&aux);
215#endif
216#ifdef CONFIG_VFP
217 if (err == 0)
218 err |= restore_vfp_context(&aux);
219#endif
220
221 return err;
222}
223
224asmlinkage int sys_sigreturn(struct pt_regs *regs)
225{
226 struct sigframe __user *frame;
227
228 /* Always make any pending restarted system calls return -EINTR */
229 current->restart_block.fn = do_no_restart_syscall;
230
231 /*
232 * Since we stacked the signal on a 64-bit boundary,
233 * then 'sp' should be word aligned here. If it's
234 * not, then the user is trying to mess with us.
235 */
236 if (regs->ARM_sp & 7)
237 goto badframe;
238
239 frame = (struct sigframe __user *)regs->ARM_sp;
240
241 if (!access_ok(frame, sizeof (*frame)))
242 goto badframe;
243
244 if (restore_sigframe(regs, frame))
245 goto badframe;
246
247 return regs->ARM_r0;
248
249badframe:
250 force_sig(SIGSEGV);
251 return 0;
252}
253
254asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
255{
256 struct rt_sigframe __user *frame;
257
258 /* Always make any pending restarted system calls return -EINTR */
259 current->restart_block.fn = do_no_restart_syscall;
260
261 /*
262 * Since we stacked the signal on a 64-bit boundary,
263 * then 'sp' should be word aligned here. If it's
264 * not, then the user is trying to mess with us.
265 */
266 if (regs->ARM_sp & 7)
267 goto badframe;
268
269 frame = (struct rt_sigframe __user *)regs->ARM_sp;
270
271 if (!access_ok(frame, sizeof (*frame)))
272 goto badframe;
273
274 if (restore_sigframe(regs, &frame->sig))
275 goto badframe;
276
277 if (restore_altstack(&frame->sig.uc.uc_stack))
278 goto badframe;
279
280 return regs->ARM_r0;
281
282badframe:
283 force_sig(SIGSEGV);
284 return 0;
285}
286
287static int
288setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
289{
290 struct aux_sigframe __user *aux;
291 struct sigcontext context;
292 int err = 0;
293
294 context = (struct sigcontext) {
295 .arm_r0 = regs->ARM_r0,
296 .arm_r1 = regs->ARM_r1,
297 .arm_r2 = regs->ARM_r2,
298 .arm_r3 = regs->ARM_r3,
299 .arm_r4 = regs->ARM_r4,
300 .arm_r5 = regs->ARM_r5,
301 .arm_r6 = regs->ARM_r6,
302 .arm_r7 = regs->ARM_r7,
303 .arm_r8 = regs->ARM_r8,
304 .arm_r9 = regs->ARM_r9,
305 .arm_r10 = regs->ARM_r10,
306 .arm_fp = regs->ARM_fp,
307 .arm_ip = regs->ARM_ip,
308 .arm_sp = regs->ARM_sp,
309 .arm_lr = regs->ARM_lr,
310 .arm_pc = regs->ARM_pc,
311 .arm_cpsr = regs->ARM_cpsr,
312
313 .trap_no = current->thread.trap_no,
314 .error_code = current->thread.error_code,
315 .fault_address = current->thread.address,
316 .oldmask = set->sig[0],
317 };
318
319 err |= __copy_to_user(&sf->uc.uc_mcontext, &context, sizeof(context));
320
321 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
322
323 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
324#ifdef CONFIG_CRUNCH
325 if (err == 0)
326 err |= preserve_crunch_context(&aux->crunch);
327#endif
328#ifdef CONFIG_IWMMXT
329 if (err == 0)
330 err |= preserve_iwmmxt_context(&aux->iwmmxt);
331#endif
332#ifdef CONFIG_VFP
333 if (err == 0)
334 err |= preserve_vfp_context(&aux->vfp);
335#endif
336 err |= __put_user(0, &aux->end_magic);
337
338 return err;
339}
340
341static inline void __user *
342get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
343{
344 unsigned long sp = sigsp(regs->ARM_sp, ksig);
345 void __user *frame;
346
347 /*
348 * ATPCS B01 mandates 8-byte alignment
349 */
350 frame = (void __user *)((sp - framesize) & ~7);
351
352 /*
353 * Check that we can actually write to the signal frame.
354 */
355 if (!access_ok(frame, framesize))
356 frame = NULL;
357
358 return frame;
359}
360
361static int
362setup_return(struct pt_regs *regs, struct ksignal *ksig,
363 unsigned long __user *rc, void __user *frame)
364{
365 unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
366 unsigned long handler_fdpic_GOT = 0;
367 unsigned long retcode;
368 unsigned int idx, thumb = 0;
369 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
370 bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&
371 (current->personality & FDPIC_FUNCPTRS);
372
373 if (fdpic) {
374 unsigned long __user *fdpic_func_desc =
375 (unsigned long __user *)handler;
376 if (__get_user(handler, &fdpic_func_desc[0]) ||
377 __get_user(handler_fdpic_GOT, &fdpic_func_desc[1]))
378 return 1;
379 }
380
381 cpsr |= PSR_ENDSTATE;
382
383 /*
384 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
385 */
386 if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
387 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
388
389#ifdef CONFIG_ARM_THUMB
390 if (elf_hwcap & HWCAP_THUMB) {
391 /*
392 * The LSB of the handler determines if we're going to
393 * be using THUMB or ARM mode for this signal handler.
394 */
395 thumb = handler & 1;
396
397 /*
398 * Clear the If-Then Thumb-2 execution state. ARM spec
399 * requires this to be all 000s in ARM mode. Snapdragon
400 * S4/Krait misbehaves on a Thumb=>ARM signal transition
401 * without this.
402 *
403 * We must do this whenever we are running on a Thumb-2
404 * capable CPU, which includes ARMv6T2. However, we elect
405 * to always do this to simplify the code; this field is
406 * marked UNK/SBZP for older architectures.
407 */
408 cpsr &= ~PSR_IT_MASK;
409
410 if (thumb) {
411 cpsr |= PSR_T_BIT;
412 } else
413 cpsr &= ~PSR_T_BIT;
414 }
415#endif
416
417 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
418 retcode = (unsigned long)ksig->ka.sa.sa_restorer;
419 if (fdpic) {
420 /*
421 * We need code to load the function descriptor.
422 * That code follows the standard sigreturn code
423 * (6 words), and is made of 3 + 2 words for each
424 * variant. The 4th copied word is the actual FD
425 * address that the assembly code expects.
426 */
427 idx = 6 + thumb * 3;
428 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
429 idx += 5;
430 if (__put_user(sigreturn_codes[idx], rc ) ||
431 __put_user(sigreturn_codes[idx+1], rc+1) ||
432 __put_user(sigreturn_codes[idx+2], rc+2) ||
433 __put_user(retcode, rc+3))
434 return 1;
435 goto rc_finish;
436 }
437 } else {
438 idx = thumb << 1;
439 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
440 idx += 3;
441
442 /*
443 * Put the sigreturn code on the stack no matter which return
444 * mechanism we use in order to remain ABI compliant
445 */
446 if (__put_user(sigreturn_codes[idx], rc) ||
447 __put_user(sigreturn_codes[idx+1], rc+1))
448 return 1;
449
450rc_finish:
451#ifdef CONFIG_MMU
452 if (cpsr & MODE32_BIT) {
453 struct mm_struct *mm = current->mm;
454
455 /*
456 * 32-bit code can use the signal return page
457 * except when the MPU has protected the vectors
458 * page from PL0
459 */
460 retcode = mm->context.sigpage + signal_return_offset +
461 (idx << 2) + thumb;
462 } else
463#endif
464 {
465 /*
466 * Ensure that the instruction cache sees
467 * the return code written onto the stack.
468 */
469 flush_icache_range((unsigned long)rc,
470 (unsigned long)(rc + 3));
471
472 retcode = ((unsigned long)rc) + thumb;
473 }
474 }
475
476 regs->ARM_r0 = ksig->sig;
477 regs->ARM_sp = (unsigned long)frame;
478 regs->ARM_lr = retcode;
479 regs->ARM_pc = handler;
480 if (fdpic)
481 regs->ARM_r9 = handler_fdpic_GOT;
482 regs->ARM_cpsr = cpsr;
483
484 return 0;
485}
486
487static int
488setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
489{
490 struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
491 int err = 0;
492
493 if (!frame)
494 return 1;
495
496 /*
497 * Set uc.uc_flags to a value which sc.trap_no would never have.
498 */
499 err = __put_user(0x5ac3c35a, &frame->uc.uc_flags);
500
501 err |= setup_sigframe(frame, regs, set);
502 if (err == 0)
503 err = setup_return(regs, ksig, frame->retcode, frame);
504
505 return err;
506}
507
508static int
509setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
510{
511 struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
512 int err = 0;
513
514 if (!frame)
515 return 1;
516
517 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
518
519 err |= __put_user(0, &frame->sig.uc.uc_flags);
520 err |= __put_user(NULL, &frame->sig.uc.uc_link);
521
522 err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
523 err |= setup_sigframe(&frame->sig, regs, set);
524 if (err == 0)
525 err = setup_return(regs, ksig, frame->sig.retcode, frame);
526
527 if (err == 0) {
528 /*
529 * For realtime signals we must also set the second and third
530 * arguments for the signal handler.
531 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
532 */
533 regs->ARM_r1 = (unsigned long)&frame->info;
534 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
535 }
536
537 return err;
538}
539
540/*
541 * OK, we're invoking a handler
542 */
543static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
544{
545 sigset_t *oldset = sigmask_to_save();
546 int ret;
547
548 /*
549 * Perform fixup for the pre-signal frame.
550 */
551 rseq_signal_deliver(ksig, regs);
552
553 /*
554 * Set up the stack frame
555 */
556 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
557 ret = setup_rt_frame(ksig, oldset, regs);
558 else
559 ret = setup_frame(ksig, oldset, regs);
560
561 /*
562 * Check that the resulting registers are actually sane.
563 */
564 ret |= !valid_user_regs(regs);
565
566 signal_setup_done(ret, ksig, 0);
567}
568
569/*
570 * Note that 'init' is a special process: it doesn't get signals it doesn't
571 * want to handle. Thus you cannot kill init even with a SIGKILL even by
572 * mistake.
573 *
574 * Note that we go through the signals twice: once to check the signals that
575 * the kernel can handle, and then we build all the user-level signal handling
576 * stack-frames in one go after that.
577 */
578static int do_signal(struct pt_regs *regs, int syscall)
579{
580 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
581 struct ksignal ksig;
582 int restart = 0;
583
584 /*
585 * If we were from a system call, check for system call restarting...
586 */
587 if (syscall) {
588 continue_addr = regs->ARM_pc;
589 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
590 retval = regs->ARM_r0;
591
592 /*
593 * Prepare for system call restart. We do this here so that a
594 * debugger will see the already changed PSW.
595 */
596 switch (retval) {
597 case -ERESTART_RESTARTBLOCK:
598 restart -= 2;
599 fallthrough;
600 case -ERESTARTNOHAND:
601 case -ERESTARTSYS:
602 case -ERESTARTNOINTR:
603 restart++;
604 regs->ARM_r0 = regs->ARM_ORIG_r0;
605 regs->ARM_pc = restart_addr;
606 break;
607 }
608 }
609
610 /*
611 * Get the signal to deliver. When running under ptrace, at this
612 * point the debugger may change all our registers ...
613 */
614 /*
615 * Depending on the signal settings we may need to revert the
616 * decision to restart the system call. But skip this if a
617 * debugger has chosen to restart at a different PC.
618 */
619 if (get_signal(&ksig)) {
620 /* handler */
621 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
622 if (retval == -ERESTARTNOHAND ||
623 retval == -ERESTART_RESTARTBLOCK
624 || (retval == -ERESTARTSYS
625 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
626 regs->ARM_r0 = -EINTR;
627 regs->ARM_pc = continue_addr;
628 }
629 }
630 handle_signal(&ksig, regs);
631 } else {
632 /* no handler */
633 restore_saved_sigmask();
634 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
635 regs->ARM_pc = continue_addr;
636 return restart;
637 }
638 }
639 return 0;
640}
641
642asmlinkage int
643do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
644{
645 /*
646 * The assembly code enters us with IRQs off, but it hasn't
647 * informed the tracing code of that for efficiency reasons.
648 * Update the trace code with the current status.
649 */
650 trace_hardirqs_off();
651 do {
652 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
653 schedule();
654 } else {
655 if (unlikely(!user_mode(regs)))
656 return 0;
657 local_irq_enable();
658 if (thread_flags & _TIF_SIGPENDING) {
659 int restart = do_signal(regs, syscall);
660 if (unlikely(restart)) {
661 /*
662 * Restart without handlers.
663 * Deal with it without leaving
664 * the kernel space.
665 */
666 return restart;
667 }
668 syscall = 0;
669 } else if (thread_flags & _TIF_UPROBE) {
670 uprobe_notify_resume(regs);
671 } else {
672 clear_thread_flag(TIF_NOTIFY_RESUME);
673 tracehook_notify_resume(regs);
674 rseq_handle_notify_resume(NULL, regs);
675 }
676 }
677 local_irq_disable();
678 thread_flags = current_thread_info()->flags;
679 } while (thread_flags & _TIF_WORK_MASK);
680 return 0;
681}
682
683struct page *get_signal_page(void)
684{
685 unsigned long ptr;
686 unsigned offset;
687 struct page *page;
688 void *addr;
689
690 page = alloc_pages(GFP_KERNEL, 0);
691
692 if (!page)
693 return NULL;
694
695 addr = page_address(page);
696
697 /* Give the signal return code some randomness */
698 offset = 0x200 + (get_random_int() & 0x7fc);
699 signal_return_offset = offset;
700
701 /*
702 * Copy signal return handlers into the vector page, and
703 * set sigreturn to be a pointer to these.
704 */
705 memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
706
707 ptr = (unsigned long)addr + offset;
708 flush_icache_range(ptr, ptr + sizeof(sigreturn_codes));
709
710 return page;
711}
712
713/* Defer to generic check */
714asmlinkage void addr_limit_check_failed(void)
715{
716#ifdef CONFIG_MMU
717 addr_limit_user_check();
718#endif
719}
720
721#ifdef CONFIG_DEBUG_RSEQ
722asmlinkage void do_rseq_syscall(struct pt_regs *regs)
723{
724 rseq_syscall(regs);
725}
726#endif
1/*
2 * linux/arch/arm/kernel/signal.c
3 *
4 * Copyright (C) 1995-2009 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/errno.h>
11#include <linux/signal.h>
12#include <linux/personality.h>
13#include <linux/freezer.h>
14#include <linux/uaccess.h>
15#include <linux/tracehook.h>
16
17#include <asm/elf.h>
18#include <asm/cacheflush.h>
19#include <asm/ucontext.h>
20#include <asm/unistd.h>
21#include <asm/vfp.h>
22
23#include "signal.h"
24
25/*
26 * For ARM syscalls, we encode the syscall number into the instruction.
27 */
28#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
29#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
30#define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
31
32/*
33 * With EABI, the syscall number has to be loaded into r7.
34 */
35#define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
36#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
37
38/*
39 * For Thumb syscalls, we pass the syscall number via r7. We therefore
40 * need two 16-bit instructions.
41 */
42#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
43#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
44
45const unsigned long sigreturn_codes[7] = {
46 MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
47 MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
48};
49
50/*
51 * Either we support OABI only, or we have EABI with the OABI
52 * compat layer enabled. In the later case we don't know if
53 * user space is EABI or not, and if not we must not clobber r7.
54 * Always using the OABI syscall solves that issue and works for
55 * all those cases.
56 */
57const unsigned long syscall_restart_code[2] = {
58 SWI_SYS_RESTART, /* swi __NR_restart_syscall */
59 0xe49df004, /* ldr pc, [sp], #4 */
60};
61
62/*
63 * atomically swap in the new signal mask, and wait for a signal.
64 */
65asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
66{
67 sigset_t blocked;
68 siginitset(&blocked, mask);
69 return sigsuspend(&blocked);
70}
71
72asmlinkage int
73sys_sigaction(int sig, const struct old_sigaction __user *act,
74 struct old_sigaction __user *oact)
75{
76 struct k_sigaction new_ka, old_ka;
77 int ret;
78
79 if (act) {
80 old_sigset_t mask;
81 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
82 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
83 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
84 __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
85 __get_user(mask, &act->sa_mask))
86 return -EFAULT;
87 siginitset(&new_ka.sa.sa_mask, mask);
88 }
89
90 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
91
92 if (!ret && oact) {
93 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
94 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
95 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
96 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
97 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
98 return -EFAULT;
99 }
100
101 return ret;
102}
103
104#ifdef CONFIG_CRUNCH
105static int preserve_crunch_context(struct crunch_sigframe __user *frame)
106{
107 char kbuf[sizeof(*frame) + 8];
108 struct crunch_sigframe *kframe;
109
110 /* the crunch context must be 64 bit aligned */
111 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
112 kframe->magic = CRUNCH_MAGIC;
113 kframe->size = CRUNCH_STORAGE_SIZE;
114 crunch_task_copy(current_thread_info(), &kframe->storage);
115 return __copy_to_user(frame, kframe, sizeof(*frame));
116}
117
118static int restore_crunch_context(struct crunch_sigframe __user *frame)
119{
120 char kbuf[sizeof(*frame) + 8];
121 struct crunch_sigframe *kframe;
122
123 /* the crunch context must be 64 bit aligned */
124 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
125 if (__copy_from_user(kframe, frame, sizeof(*frame)))
126 return -1;
127 if (kframe->magic != CRUNCH_MAGIC ||
128 kframe->size != CRUNCH_STORAGE_SIZE)
129 return -1;
130 crunch_task_restore(current_thread_info(), &kframe->storage);
131 return 0;
132}
133#endif
134
135#ifdef CONFIG_IWMMXT
136
137static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
138{
139 char kbuf[sizeof(*frame) + 8];
140 struct iwmmxt_sigframe *kframe;
141
142 /* the iWMMXt context must be 64 bit aligned */
143 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
144 kframe->magic = IWMMXT_MAGIC;
145 kframe->size = IWMMXT_STORAGE_SIZE;
146 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
147 return __copy_to_user(frame, kframe, sizeof(*frame));
148}
149
150static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
151{
152 char kbuf[sizeof(*frame) + 8];
153 struct iwmmxt_sigframe *kframe;
154
155 /* the iWMMXt context must be 64 bit aligned */
156 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
157 if (__copy_from_user(kframe, frame, sizeof(*frame)))
158 return -1;
159 if (kframe->magic != IWMMXT_MAGIC ||
160 kframe->size != IWMMXT_STORAGE_SIZE)
161 return -1;
162 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
163 return 0;
164}
165
166#endif
167
168#ifdef CONFIG_VFP
169
170static int preserve_vfp_context(struct vfp_sigframe __user *frame)
171{
172 const unsigned long magic = VFP_MAGIC;
173 const unsigned long size = VFP_STORAGE_SIZE;
174 int err = 0;
175
176 __put_user_error(magic, &frame->magic, err);
177 __put_user_error(size, &frame->size, err);
178
179 if (err)
180 return -EFAULT;
181
182 return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
183}
184
185static int restore_vfp_context(struct vfp_sigframe __user *frame)
186{
187 unsigned long magic;
188 unsigned long size;
189 int err = 0;
190
191 __get_user_error(magic, &frame->magic, err);
192 __get_user_error(size, &frame->size, err);
193
194 if (err)
195 return -EFAULT;
196 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
197 return -EINVAL;
198
199 return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
200}
201
202#endif
203
204/*
205 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
206 */
207struct sigframe {
208 struct ucontext uc;
209 unsigned long retcode[2];
210};
211
212struct rt_sigframe {
213 struct siginfo info;
214 struct sigframe sig;
215};
216
217static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
218{
219 struct aux_sigframe __user *aux;
220 sigset_t set;
221 int err;
222
223 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
224 if (err == 0)
225 set_current_blocked(&set);
226
227 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
228 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
229 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
230 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
231 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
232 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
233 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
234 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
235 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
236 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
237 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
238 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
239 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
240 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
241 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
242 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
243 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
244
245 err |= !valid_user_regs(regs);
246
247 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
248#ifdef CONFIG_CRUNCH
249 if (err == 0)
250 err |= restore_crunch_context(&aux->crunch);
251#endif
252#ifdef CONFIG_IWMMXT
253 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
254 err |= restore_iwmmxt_context(&aux->iwmmxt);
255#endif
256#ifdef CONFIG_VFP
257 if (err == 0)
258 err |= restore_vfp_context(&aux->vfp);
259#endif
260
261 return err;
262}
263
264asmlinkage int sys_sigreturn(struct pt_regs *regs)
265{
266 struct sigframe __user *frame;
267
268 /* Always make any pending restarted system calls return -EINTR */
269 current_thread_info()->restart_block.fn = do_no_restart_syscall;
270
271 /*
272 * Since we stacked the signal on a 64-bit boundary,
273 * then 'sp' should be word aligned here. If it's
274 * not, then the user is trying to mess with us.
275 */
276 if (regs->ARM_sp & 7)
277 goto badframe;
278
279 frame = (struct sigframe __user *)regs->ARM_sp;
280
281 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
282 goto badframe;
283
284 if (restore_sigframe(regs, frame))
285 goto badframe;
286
287 return regs->ARM_r0;
288
289badframe:
290 force_sig(SIGSEGV, current);
291 return 0;
292}
293
294asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
295{
296 struct rt_sigframe __user *frame;
297
298 /* Always make any pending restarted system calls return -EINTR */
299 current_thread_info()->restart_block.fn = do_no_restart_syscall;
300
301 /*
302 * Since we stacked the signal on a 64-bit boundary,
303 * then 'sp' should be word aligned here. If it's
304 * not, then the user is trying to mess with us.
305 */
306 if (regs->ARM_sp & 7)
307 goto badframe;
308
309 frame = (struct rt_sigframe __user *)regs->ARM_sp;
310
311 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
312 goto badframe;
313
314 if (restore_sigframe(regs, &frame->sig))
315 goto badframe;
316
317 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
318 goto badframe;
319
320 return regs->ARM_r0;
321
322badframe:
323 force_sig(SIGSEGV, current);
324 return 0;
325}
326
327static int
328setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
329{
330 struct aux_sigframe __user *aux;
331 int err = 0;
332
333 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
334 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
335 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
336 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
337 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
338 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
339 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
340 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
341 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
342 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
343 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
344 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
345 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
346 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
347 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
348 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
349 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
350
351 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
352 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
353 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
354 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
355
356 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
357
358 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
359#ifdef CONFIG_CRUNCH
360 if (err == 0)
361 err |= preserve_crunch_context(&aux->crunch);
362#endif
363#ifdef CONFIG_IWMMXT
364 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
365 err |= preserve_iwmmxt_context(&aux->iwmmxt);
366#endif
367#ifdef CONFIG_VFP
368 if (err == 0)
369 err |= preserve_vfp_context(&aux->vfp);
370#endif
371 __put_user_error(0, &aux->end_magic, err);
372
373 return err;
374}
375
376static inline void __user *
377get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
378{
379 unsigned long sp = regs->ARM_sp;
380 void __user *frame;
381
382 /*
383 * This is the X/Open sanctioned signal stack switching.
384 */
385 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
386 sp = current->sas_ss_sp + current->sas_ss_size;
387
388 /*
389 * ATPCS B01 mandates 8-byte alignment
390 */
391 frame = (void __user *)((sp - framesize) & ~7);
392
393 /*
394 * Check that we can actually write to the signal frame.
395 */
396 if (!access_ok(VERIFY_WRITE, frame, framesize))
397 frame = NULL;
398
399 return frame;
400}
401
402static int
403setup_return(struct pt_regs *regs, struct k_sigaction *ka,
404 unsigned long __user *rc, void __user *frame, int usig)
405{
406 unsigned long handler = (unsigned long)ka->sa.sa_handler;
407 unsigned long retcode;
408 int thumb = 0;
409 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
410
411 cpsr |= PSR_ENDSTATE;
412
413 /*
414 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
415 */
416 if (ka->sa.sa_flags & SA_THIRTYTWO)
417 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
418
419#ifdef CONFIG_ARM_THUMB
420 if (elf_hwcap & HWCAP_THUMB) {
421 /*
422 * The LSB of the handler determines if we're going to
423 * be using THUMB or ARM mode for this signal handler.
424 */
425 thumb = handler & 1;
426
427 if (thumb) {
428 cpsr |= PSR_T_BIT;
429#if __LINUX_ARM_ARCH__ >= 7
430 /* clear the If-Then Thumb-2 execution state */
431 cpsr &= ~PSR_IT_MASK;
432#endif
433 } else
434 cpsr &= ~PSR_T_BIT;
435 }
436#endif
437
438 if (ka->sa.sa_flags & SA_RESTORER) {
439 retcode = (unsigned long)ka->sa.sa_restorer;
440 } else {
441 unsigned int idx = thumb << 1;
442
443 if (ka->sa.sa_flags & SA_SIGINFO)
444 idx += 3;
445
446 if (__put_user(sigreturn_codes[idx], rc) ||
447 __put_user(sigreturn_codes[idx+1], rc+1))
448 return 1;
449
450 if (cpsr & MODE32_BIT) {
451 /*
452 * 32-bit code can use the new high-page
453 * signal return code support.
454 */
455 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
456 } else {
457 /*
458 * Ensure that the instruction cache sees
459 * the return code written onto the stack.
460 */
461 flush_icache_range((unsigned long)rc,
462 (unsigned long)(rc + 2));
463
464 retcode = ((unsigned long)rc) + thumb;
465 }
466 }
467
468 regs->ARM_r0 = usig;
469 regs->ARM_sp = (unsigned long)frame;
470 regs->ARM_lr = retcode;
471 regs->ARM_pc = handler;
472 regs->ARM_cpsr = cpsr;
473
474 return 0;
475}
476
477static int
478setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
479{
480 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
481 int err = 0;
482
483 if (!frame)
484 return 1;
485
486 /*
487 * Set uc.uc_flags to a value which sc.trap_no would never have.
488 */
489 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
490
491 err |= setup_sigframe(frame, regs, set);
492 if (err == 0)
493 err = setup_return(regs, ka, frame->retcode, frame, usig);
494
495 return err;
496}
497
498static int
499setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
500 sigset_t *set, struct pt_regs *regs)
501{
502 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
503 stack_t stack;
504 int err = 0;
505
506 if (!frame)
507 return 1;
508
509 err |= copy_siginfo_to_user(&frame->info, info);
510
511 __put_user_error(0, &frame->sig.uc.uc_flags, err);
512 __put_user_error(NULL, &frame->sig.uc.uc_link, err);
513
514 memset(&stack, 0, sizeof(stack));
515 stack.ss_sp = (void __user *)current->sas_ss_sp;
516 stack.ss_flags = sas_ss_flags(regs->ARM_sp);
517 stack.ss_size = current->sas_ss_size;
518 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
519
520 err |= setup_sigframe(&frame->sig, regs, set);
521 if (err == 0)
522 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
523
524 if (err == 0) {
525 /*
526 * For realtime signals we must also set the second and third
527 * arguments for the signal handler.
528 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
529 */
530 regs->ARM_r1 = (unsigned long)&frame->info;
531 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
532 }
533
534 return err;
535}
536
537/*
538 * OK, we're invoking a handler
539 */
540static void
541handle_signal(unsigned long sig, struct k_sigaction *ka,
542 siginfo_t *info, struct pt_regs *regs)
543{
544 struct thread_info *thread = current_thread_info();
545 struct task_struct *tsk = current;
546 sigset_t *oldset = sigmask_to_save();
547 int usig = sig;
548 int ret;
549
550 /*
551 * translate the signal
552 */
553 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
554 usig = thread->exec_domain->signal_invmap[usig];
555
556 /*
557 * Set up the stack frame
558 */
559 if (ka->sa.sa_flags & SA_SIGINFO)
560 ret = setup_rt_frame(usig, ka, info, oldset, regs);
561 else
562 ret = setup_frame(usig, ka, oldset, regs);
563
564 /*
565 * Check that the resulting registers are actually sane.
566 */
567 ret |= !valid_user_regs(regs);
568
569 if (ret != 0) {
570 force_sigsegv(sig, tsk);
571 return;
572 }
573 signal_delivered(sig, info, ka, regs, 0);
574}
575
576/*
577 * Note that 'init' is a special process: it doesn't get signals it doesn't
578 * want to handle. Thus you cannot kill init even with a SIGKILL even by
579 * mistake.
580 *
581 * Note that we go through the signals twice: once to check the signals that
582 * the kernel can handle, and then we build all the user-level signal handling
583 * stack-frames in one go after that.
584 */
585static void do_signal(struct pt_regs *regs, int syscall)
586{
587 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
588 struct k_sigaction ka;
589 siginfo_t info;
590 int signr;
591
592 /*
593 * If we were from a system call, check for system call restarting...
594 */
595 if (syscall) {
596 continue_addr = regs->ARM_pc;
597 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
598 retval = regs->ARM_r0;
599
600 /*
601 * Prepare for system call restart. We do this here so that a
602 * debugger will see the already changed PSW.
603 */
604 switch (retval) {
605 case -ERESTARTNOHAND:
606 case -ERESTARTSYS:
607 case -ERESTARTNOINTR:
608 regs->ARM_r0 = regs->ARM_ORIG_r0;
609 regs->ARM_pc = restart_addr;
610 break;
611 case -ERESTART_RESTARTBLOCK:
612 regs->ARM_r0 = -EINTR;
613 break;
614 }
615 }
616
617 /*
618 * Get the signal to deliver. When running under ptrace, at this
619 * point the debugger may change all our registers ...
620 */
621 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
622 if (signr > 0) {
623 /*
624 * Depending on the signal settings we may need to revert the
625 * decision to restart the system call. But skip this if a
626 * debugger has chosen to restart at a different PC.
627 */
628 if (regs->ARM_pc == restart_addr) {
629 if (retval == -ERESTARTNOHAND
630 || (retval == -ERESTARTSYS
631 && !(ka.sa.sa_flags & SA_RESTART))) {
632 regs->ARM_r0 = -EINTR;
633 regs->ARM_pc = continue_addr;
634 }
635 }
636
637 handle_signal(signr, &ka, &info, regs);
638 return;
639 }
640
641 if (syscall) {
642 /*
643 * Handle restarting a different system call. As above,
644 * if a debugger has chosen to restart at a different PC,
645 * ignore the restart.
646 */
647 if (retval == -ERESTART_RESTARTBLOCK
648 && regs->ARM_pc == continue_addr) {
649 if (thumb_mode(regs)) {
650 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
651 regs->ARM_pc -= 2;
652 } else {
653#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
654 regs->ARM_r7 = __NR_restart_syscall;
655 regs->ARM_pc -= 4;
656#else
657 u32 __user *usp;
658
659 regs->ARM_sp -= 4;
660 usp = (u32 __user *)regs->ARM_sp;
661
662 if (put_user(regs->ARM_pc, usp) == 0) {
663 regs->ARM_pc = KERN_RESTART_CODE;
664 } else {
665 regs->ARM_sp += 4;
666 force_sigsegv(0, current);
667 }
668#endif
669 }
670 }
671 }
672
673 restore_saved_sigmask();
674}
675
676asmlinkage void
677do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
678{
679 if (thread_flags & _TIF_SIGPENDING)
680 do_signal(regs, syscall);
681
682 if (thread_flags & _TIF_NOTIFY_RESUME) {
683 clear_thread_flag(TIF_NOTIFY_RESUME);
684 tracehook_notify_resume(regs);
685 }
686}