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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#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
26
27/*
28 * For ARM syscalls, we encode the syscall number into the instruction.
29 */
30#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
31#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
32#define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
33
34/*
35 * With EABI, the syscall number has to be loaded into r7.
36 */
37#define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
38#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
39
40/*
41 * For Thumb syscalls, we pass the syscall number via r7. We therefore
42 * need two 16-bit instructions.
43 */
44#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
45#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
46
47const unsigned long sigreturn_codes[7] = {
48 MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
49 MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
50};
51
52/*
53 * Either we support OABI only, or we have EABI with the OABI
54 * compat layer enabled. In the later case we don't know if
55 * user space is EABI or not, and if not we must not clobber r7.
56 * Always using the OABI syscall solves that issue and works for
57 * all those cases.
58 */
59const unsigned long syscall_restart_code[2] = {
60 SWI_SYS_RESTART, /* swi __NR_restart_syscall */
61 0xe49df004, /* ldr pc, [sp], #4 */
62};
63
64/*
65 * atomically swap in the new signal mask, and wait for a signal.
66 */
67asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
68{
69 mask &= _BLOCKABLE;
70 spin_lock_irq(¤t->sighand->siglock);
71 current->saved_sigmask = current->blocked;
72 siginitset(¤t->blocked, mask);
73 recalc_sigpending();
74 spin_unlock_irq(¤t->sighand->siglock);
75
76 current->state = TASK_INTERRUPTIBLE;
77 schedule();
78 set_restore_sigmask();
79 return -ERESTARTNOHAND;
80}
81
82asmlinkage int
83sys_sigaction(int sig, const struct old_sigaction __user *act,
84 struct old_sigaction __user *oact)
85{
86 struct k_sigaction new_ka, old_ka;
87 int ret;
88
89 if (act) {
90 old_sigset_t mask;
91 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
92 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
93 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
94 return -EFAULT;
95 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
96 __get_user(mask, &act->sa_mask);
97 siginitset(&new_ka.sa.sa_mask, mask);
98 }
99
100 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
101
102 if (!ret && oact) {
103 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
104 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
105 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
106 return -EFAULT;
107 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
108 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
109 }
110
111 return ret;
112}
113
114#ifdef CONFIG_CRUNCH
115static int preserve_crunch_context(struct crunch_sigframe __user *frame)
116{
117 char kbuf[sizeof(*frame) + 8];
118 struct crunch_sigframe *kframe;
119
120 /* the crunch context must be 64 bit aligned */
121 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
122 kframe->magic = CRUNCH_MAGIC;
123 kframe->size = CRUNCH_STORAGE_SIZE;
124 crunch_task_copy(current_thread_info(), &kframe->storage);
125 return __copy_to_user(frame, kframe, sizeof(*frame));
126}
127
128static int restore_crunch_context(struct crunch_sigframe __user *frame)
129{
130 char kbuf[sizeof(*frame) + 8];
131 struct crunch_sigframe *kframe;
132
133 /* the crunch context must be 64 bit aligned */
134 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
135 if (__copy_from_user(kframe, frame, sizeof(*frame)))
136 return -1;
137 if (kframe->magic != CRUNCH_MAGIC ||
138 kframe->size != CRUNCH_STORAGE_SIZE)
139 return -1;
140 crunch_task_restore(current_thread_info(), &kframe->storage);
141 return 0;
142}
143#endif
144
145#ifdef CONFIG_IWMMXT
146
147static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
148{
149 char kbuf[sizeof(*frame) + 8];
150 struct iwmmxt_sigframe *kframe;
151
152 /* the iWMMXt context must be 64 bit aligned */
153 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
154 kframe->magic = IWMMXT_MAGIC;
155 kframe->size = IWMMXT_STORAGE_SIZE;
156 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
157 return __copy_to_user(frame, kframe, sizeof(*frame));
158}
159
160static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
161{
162 char kbuf[sizeof(*frame) + 8];
163 struct iwmmxt_sigframe *kframe;
164
165 /* the iWMMXt context must be 64 bit aligned */
166 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
167 if (__copy_from_user(kframe, frame, sizeof(*frame)))
168 return -1;
169 if (kframe->magic != IWMMXT_MAGIC ||
170 kframe->size != IWMMXT_STORAGE_SIZE)
171 return -1;
172 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
173 return 0;
174}
175
176#endif
177
178#ifdef CONFIG_VFP
179
180static int preserve_vfp_context(struct vfp_sigframe __user *frame)
181{
182 struct thread_info *thread = current_thread_info();
183 struct vfp_hard_struct *h = &thread->vfpstate.hard;
184 const unsigned long magic = VFP_MAGIC;
185 const unsigned long size = VFP_STORAGE_SIZE;
186 int err = 0;
187
188 vfp_sync_hwstate(thread);
189 __put_user_error(magic, &frame->magic, err);
190 __put_user_error(size, &frame->size, err);
191
192 /*
193 * Copy the floating point registers. There can be unused
194 * registers see asm/hwcap.h for details.
195 */
196 err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs,
197 sizeof(h->fpregs));
198 /*
199 * Copy the status and control register.
200 */
201 __put_user_error(h->fpscr, &frame->ufp.fpscr, err);
202
203 /*
204 * Copy the exception registers.
205 */
206 __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err);
207 __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
208 __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
209
210 return err ? -EFAULT : 0;
211}
212
213static int restore_vfp_context(struct vfp_sigframe __user *frame)
214{
215 struct thread_info *thread = current_thread_info();
216 struct vfp_hard_struct *h = &thread->vfpstate.hard;
217 unsigned long magic;
218 unsigned long size;
219 unsigned long fpexc;
220 int err = 0;
221
222 __get_user_error(magic, &frame->magic, err);
223 __get_user_error(size, &frame->size, err);
224
225 if (err)
226 return -EFAULT;
227 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
228 return -EINVAL;
229
230 /*
231 * Copy the floating point registers. There can be unused
232 * registers see asm/hwcap.h for details.
233 */
234 err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs,
235 sizeof(h->fpregs));
236 /*
237 * Copy the status and control register.
238 */
239 __get_user_error(h->fpscr, &frame->ufp.fpscr, err);
240
241 /*
242 * Sanitise and restore the exception registers.
243 */
244 __get_user_error(fpexc, &frame->ufp_exc.fpexc, err);
245 /* Ensure the VFP is enabled. */
246 fpexc |= FPEXC_EN;
247 /* Ensure FPINST2 is invalid and the exception flag is cleared. */
248 fpexc &= ~(FPEXC_EX | FPEXC_FP2V);
249 h->fpexc = fpexc;
250
251 __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
252 __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
253
254 if (!err)
255 vfp_flush_hwstate(thread);
256
257 return err ? -EFAULT : 0;
258}
259
260#endif
261
262/*
263 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
264 */
265struct sigframe {
266 struct ucontext uc;
267 unsigned long retcode[2];
268};
269
270struct rt_sigframe {
271 struct siginfo info;
272 struct sigframe sig;
273};
274
275static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
276{
277 struct aux_sigframe __user *aux;
278 sigset_t set;
279 int err;
280
281 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
282 if (err == 0) {
283 sigdelsetmask(&set, ~_BLOCKABLE);
284 spin_lock_irq(¤t->sighand->siglock);
285 current->blocked = set;
286 recalc_sigpending();
287 spin_unlock_irq(¤t->sighand->siglock);
288 }
289
290 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
291 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
292 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
293 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
294 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
295 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
296 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
297 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
298 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
299 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
300 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
301 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
302 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
303 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
304 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
305 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
306 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
307
308 err |= !valid_user_regs(regs);
309
310 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
311#ifdef CONFIG_CRUNCH
312 if (err == 0)
313 err |= restore_crunch_context(&aux->crunch);
314#endif
315#ifdef CONFIG_IWMMXT
316 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
317 err |= restore_iwmmxt_context(&aux->iwmmxt);
318#endif
319#ifdef CONFIG_VFP
320 if (err == 0)
321 err |= restore_vfp_context(&aux->vfp);
322#endif
323
324 return err;
325}
326
327asmlinkage int sys_sigreturn(struct pt_regs *regs)
328{
329 struct sigframe __user *frame;
330
331 /* Always make any pending restarted system calls return -EINTR */
332 current_thread_info()->restart_block.fn = do_no_restart_syscall;
333
334 /*
335 * Since we stacked the signal on a 64-bit boundary,
336 * then 'sp' should be word aligned here. If it's
337 * not, then the user is trying to mess with us.
338 */
339 if (regs->ARM_sp & 7)
340 goto badframe;
341
342 frame = (struct sigframe __user *)regs->ARM_sp;
343
344 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
345 goto badframe;
346
347 if (restore_sigframe(regs, frame))
348 goto badframe;
349
350 return regs->ARM_r0;
351
352badframe:
353 force_sig(SIGSEGV, current);
354 return 0;
355}
356
357asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
358{
359 struct rt_sigframe __user *frame;
360
361 /* Always make any pending restarted system calls return -EINTR */
362 current_thread_info()->restart_block.fn = do_no_restart_syscall;
363
364 /*
365 * Since we stacked the signal on a 64-bit boundary,
366 * then 'sp' should be word aligned here. If it's
367 * not, then the user is trying to mess with us.
368 */
369 if (regs->ARM_sp & 7)
370 goto badframe;
371
372 frame = (struct rt_sigframe __user *)regs->ARM_sp;
373
374 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
375 goto badframe;
376
377 if (restore_sigframe(regs, &frame->sig))
378 goto badframe;
379
380 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
381 goto badframe;
382
383 return regs->ARM_r0;
384
385badframe:
386 force_sig(SIGSEGV, current);
387 return 0;
388}
389
390static int
391setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
392{
393 struct aux_sigframe __user *aux;
394 int err = 0;
395
396 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
397 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
398 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
399 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
400 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
401 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
402 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
403 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
404 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
405 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
406 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
407 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
408 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
409 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
410 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
411 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
412 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
413
414 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
415 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
416 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
417 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
418
419 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
420
421 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
422#ifdef CONFIG_CRUNCH
423 if (err == 0)
424 err |= preserve_crunch_context(&aux->crunch);
425#endif
426#ifdef CONFIG_IWMMXT
427 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
428 err |= preserve_iwmmxt_context(&aux->iwmmxt);
429#endif
430#ifdef CONFIG_VFP
431 if (err == 0)
432 err |= preserve_vfp_context(&aux->vfp);
433#endif
434 __put_user_error(0, &aux->end_magic, err);
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 | PSR_E_BIT);
473
474 cpsr |= PSR_ENDSTATE;
475
476 /*
477 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
478 */
479 if (ka->sa.sa_flags & SA_THIRTYTWO)
480 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
481
482#ifdef CONFIG_ARM_THUMB
483 if (elf_hwcap & HWCAP_THUMB) {
484 /*
485 * The LSB of the handler determines if we're going to
486 * be using THUMB or ARM mode for this signal handler.
487 */
488 thumb = handler & 1;
489
490 if (thumb) {
491 cpsr |= PSR_T_BIT;
492#if __LINUX_ARM_ARCH__ >= 7
493 /* clear the If-Then Thumb-2 execution state */
494 cpsr &= ~PSR_IT_MASK;
495#endif
496 } else
497 cpsr &= ~PSR_T_BIT;
498 }
499#endif
500
501 if (ka->sa.sa_flags & SA_RESTORER) {
502 retcode = (unsigned long)ka->sa.sa_restorer;
503 } else {
504 unsigned int idx = thumb << 1;
505
506 if (ka->sa.sa_flags & SA_SIGINFO)
507 idx += 3;
508
509 if (__put_user(sigreturn_codes[idx], rc) ||
510 __put_user(sigreturn_codes[idx+1], rc+1))
511 return 1;
512
513 if (cpsr & MODE32_BIT) {
514 /*
515 * 32-bit code can use the new high-page
516 * signal return code support.
517 */
518 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
519 } else {
520 /*
521 * Ensure that the instruction cache sees
522 * the return code written onto the stack.
523 */
524 flush_icache_range((unsigned long)rc,
525 (unsigned long)(rc + 2));
526
527 retcode = ((unsigned long)rc) + thumb;
528 }
529 }
530
531 regs->ARM_r0 = usig;
532 regs->ARM_sp = (unsigned long)frame;
533 regs->ARM_lr = retcode;
534 regs->ARM_pc = handler;
535 regs->ARM_cpsr = cpsr;
536
537 return 0;
538}
539
540static int
541setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
542{
543 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
544 int err = 0;
545
546 if (!frame)
547 return 1;
548
549 /*
550 * Set uc.uc_flags to a value which sc.trap_no would never have.
551 */
552 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
553
554 err |= setup_sigframe(frame, regs, set);
555 if (err == 0)
556 err = setup_return(regs, ka, frame->retcode, frame, usig);
557
558 return err;
559}
560
561static int
562setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
563 sigset_t *set, struct pt_regs *regs)
564{
565 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
566 stack_t stack;
567 int err = 0;
568
569 if (!frame)
570 return 1;
571
572 err |= copy_siginfo_to_user(&frame->info, info);
573
574 __put_user_error(0, &frame->sig.uc.uc_flags, err);
575 __put_user_error(NULL, &frame->sig.uc.uc_link, err);
576
577 memset(&stack, 0, sizeof(stack));
578 stack.ss_sp = (void __user *)current->sas_ss_sp;
579 stack.ss_flags = sas_ss_flags(regs->ARM_sp);
580 stack.ss_size = current->sas_ss_size;
581 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
582
583 err |= setup_sigframe(&frame->sig, regs, set);
584 if (err == 0)
585 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
586
587 if (err == 0) {
588 /*
589 * For realtime signals we must also set the second and third
590 * arguments for the signal handler.
591 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
592 */
593 regs->ARM_r1 = (unsigned long)&frame->info;
594 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
595 }
596
597 return err;
598}
599
600/*
601 * OK, we're invoking a handler
602 */
603static int
604handle_signal(unsigned long sig, struct k_sigaction *ka,
605 siginfo_t *info, sigset_t *oldset,
606 struct pt_regs * regs)
607{
608 struct thread_info *thread = current_thread_info();
609 struct task_struct *tsk = current;
610 int usig = sig;
611 int ret;
612
613 /*
614 * translate the signal
615 */
616 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
617 usig = thread->exec_domain->signal_invmap[usig];
618
619 /*
620 * Set up the stack frame
621 */
622 if (ka->sa.sa_flags & SA_SIGINFO)
623 ret = setup_rt_frame(usig, ka, info, oldset, regs);
624 else
625 ret = setup_frame(usig, ka, oldset, regs);
626
627 /*
628 * Check that the resulting registers are actually sane.
629 */
630 ret |= !valid_user_regs(regs);
631
632 if (ret != 0) {
633 force_sigsegv(sig, tsk);
634 return ret;
635 }
636
637 /*
638 * Block the signal if we were successful.
639 */
640 spin_lock_irq(&tsk->sighand->siglock);
641 sigorsets(&tsk->blocked, &tsk->blocked,
642 &ka->sa.sa_mask);
643 if (!(ka->sa.sa_flags & SA_NODEFER))
644 sigaddset(&tsk->blocked, sig);
645 recalc_sigpending();
646 spin_unlock_irq(&tsk->sighand->siglock);
647
648 return 0;
649}
650
651/*
652 * Note that 'init' is a special process: it doesn't get signals it doesn't
653 * want to handle. Thus you cannot kill init even with a SIGKILL even by
654 * mistake.
655 *
656 * Note that we go through the signals twice: once to check the signals that
657 * the kernel can handle, and then we build all the user-level signal handling
658 * stack-frames in one go after that.
659 */
660static void do_signal(struct pt_regs *regs, int syscall)
661{
662 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
663 struct k_sigaction ka;
664 siginfo_t info;
665 int signr;
666
667 /*
668 * We want the common case to go fast, which
669 * is why we may in certain cases get here from
670 * kernel mode. Just return without doing anything
671 * if so.
672 */
673 if (!user_mode(regs))
674 return;
675
676 /*
677 * If we were from a system call, check for system call restarting...
678 */
679 if (syscall) {
680 continue_addr = regs->ARM_pc;
681 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
682 retval = regs->ARM_r0;
683
684 /*
685 * Prepare for system call restart. We do this here so that a
686 * debugger will see the already changed PSW.
687 */
688 switch (retval) {
689 case -ERESTARTNOHAND:
690 case -ERESTARTSYS:
691 case -ERESTARTNOINTR:
692 regs->ARM_r0 = regs->ARM_ORIG_r0;
693 regs->ARM_pc = restart_addr;
694 break;
695 case -ERESTART_RESTARTBLOCK:
696 regs->ARM_r0 = -EINTR;
697 break;
698 }
699 }
700
701 if (try_to_freeze())
702 goto no_signal;
703
704 /*
705 * Get the signal to deliver. When running under ptrace, at this
706 * point the debugger may change all our registers ...
707 */
708 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
709 if (signr > 0) {
710 sigset_t *oldset;
711
712 /*
713 * Depending on the signal settings we may need to revert the
714 * decision to restart the system call. But skip this if a
715 * debugger has chosen to restart at a different PC.
716 */
717 if (regs->ARM_pc == restart_addr) {
718 if (retval == -ERESTARTNOHAND
719 || (retval == -ERESTARTSYS
720 && !(ka.sa.sa_flags & SA_RESTART))) {
721 regs->ARM_r0 = -EINTR;
722 regs->ARM_pc = continue_addr;
723 }
724 }
725
726 if (test_thread_flag(TIF_RESTORE_SIGMASK))
727 oldset = ¤t->saved_sigmask;
728 else
729 oldset = ¤t->blocked;
730 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
731 /*
732 * A signal was successfully delivered; the saved
733 * sigmask will have been stored in the signal frame,
734 * and will be restored by sigreturn, so we can simply
735 * clear the TIF_RESTORE_SIGMASK flag.
736 */
737 if (test_thread_flag(TIF_RESTORE_SIGMASK))
738 clear_thread_flag(TIF_RESTORE_SIGMASK);
739 }
740 return;
741 }
742
743 no_signal:
744 if (syscall) {
745 /*
746 * Handle restarting a different system call. As above,
747 * if a debugger has chosen to restart at a different PC,
748 * ignore the restart.
749 */
750 if (retval == -ERESTART_RESTARTBLOCK
751 && regs->ARM_pc == continue_addr) {
752 if (thumb_mode(regs)) {
753 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
754 regs->ARM_pc -= 2;
755 } else {
756#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
757 regs->ARM_r7 = __NR_restart_syscall;
758 regs->ARM_pc -= 4;
759#else
760 u32 __user *usp;
761
762 regs->ARM_sp -= 4;
763 usp = (u32 __user *)regs->ARM_sp;
764
765 if (put_user(regs->ARM_pc, usp) == 0) {
766 regs->ARM_pc = KERN_RESTART_CODE;
767 } else {
768 regs->ARM_sp += 4;
769 force_sigsegv(0, current);
770 }
771#endif
772 }
773 }
774
775 /* If there's no signal to deliver, we just put the saved sigmask
776 * back.
777 */
778 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
779 clear_thread_flag(TIF_RESTORE_SIGMASK);
780 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
781 }
782 }
783}
784
785asmlinkage void
786do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
787{
788 if (thread_flags & _TIF_SIGPENDING)
789 do_signal(regs, syscall);
790
791 if (thread_flags & _TIF_NOTIFY_RESUME) {
792 clear_thread_flag(TIF_NOTIFY_RESUME);
793 tracehook_notify_resume(regs);
794 if (current->replacement_session_keyring)
795 key_replace_session_keyring();
796 }
797}
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/resume_user_mode.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_IWMMXT
29
30static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
31{
32 char kbuf[sizeof(*frame) + 8];
33 struct iwmmxt_sigframe *kframe;
34 int err = 0;
35
36 /* the iWMMXt context must be 64 bit aligned */
37 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
38
39 if (test_thread_flag(TIF_USING_IWMMXT)) {
40 kframe->magic = IWMMXT_MAGIC;
41 kframe->size = IWMMXT_STORAGE_SIZE;
42 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
43 } else {
44 /*
45 * For bug-compatibility with older kernels, some space
46 * has to be reserved for iWMMXt even if it's not used.
47 * Set the magic and size appropriately so that properly
48 * written userspace can skip it reliably:
49 */
50 *kframe = (struct iwmmxt_sigframe) {
51 .magic = DUMMY_MAGIC,
52 .size = IWMMXT_STORAGE_SIZE,
53 };
54 }
55
56 err = __copy_to_user(frame, kframe, sizeof(*kframe));
57
58 return err;
59}
60
61static int restore_iwmmxt_context(char __user **auxp)
62{
63 struct iwmmxt_sigframe __user *frame =
64 (struct iwmmxt_sigframe __user *)*auxp;
65 char kbuf[sizeof(*frame) + 8];
66 struct iwmmxt_sigframe *kframe;
67
68 /* the iWMMXt context must be 64 bit aligned */
69 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
70 if (__copy_from_user(kframe, frame, sizeof(*frame)))
71 return -1;
72
73 /*
74 * For non-iWMMXt threads: a single iwmmxt_sigframe-sized dummy
75 * block is discarded for compatibility with setup_sigframe() if
76 * present, but we don't mandate its presence. If some other
77 * magic is here, it's not for us:
78 */
79 if (!test_thread_flag(TIF_USING_IWMMXT) &&
80 kframe->magic != DUMMY_MAGIC)
81 return 0;
82
83 if (kframe->size != IWMMXT_STORAGE_SIZE)
84 return -1;
85
86 if (test_thread_flag(TIF_USING_IWMMXT)) {
87 if (kframe->magic != IWMMXT_MAGIC)
88 return -1;
89
90 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
91 }
92
93 *auxp += IWMMXT_STORAGE_SIZE;
94 return 0;
95}
96
97#endif
98
99#ifdef CONFIG_VFP
100
101static int preserve_vfp_context(struct vfp_sigframe __user *frame)
102{
103 struct vfp_sigframe kframe;
104 int err = 0;
105
106 memset(&kframe, 0, sizeof(kframe));
107 kframe.magic = VFP_MAGIC;
108 kframe.size = VFP_STORAGE_SIZE;
109
110 err = vfp_preserve_user_clear_hwstate(&kframe.ufp, &kframe.ufp_exc);
111 if (err)
112 return err;
113
114 return __copy_to_user(frame, &kframe, sizeof(kframe));
115}
116
117static int restore_vfp_context(char __user **auxp)
118{
119 struct vfp_sigframe frame;
120 int err;
121
122 err = __copy_from_user(&frame, *auxp, sizeof(frame));
123 if (err)
124 return err;
125
126 if (frame.magic != VFP_MAGIC || frame.size != VFP_STORAGE_SIZE)
127 return -EINVAL;
128
129 *auxp += sizeof(frame);
130 return vfp_restore_user_hwstate(&frame.ufp, &frame.ufp_exc);
131}
132
133#endif
134
135/*
136 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
137 */
138
139static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
140{
141 struct sigcontext context;
142 char __user *aux;
143 sigset_t set;
144 int err;
145
146 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
147 if (err == 0)
148 set_current_blocked(&set);
149
150 err |= __copy_from_user(&context, &sf->uc.uc_mcontext, sizeof(context));
151 if (err == 0) {
152 regs->ARM_r0 = context.arm_r0;
153 regs->ARM_r1 = context.arm_r1;
154 regs->ARM_r2 = context.arm_r2;
155 regs->ARM_r3 = context.arm_r3;
156 regs->ARM_r4 = context.arm_r4;
157 regs->ARM_r5 = context.arm_r5;
158 regs->ARM_r6 = context.arm_r6;
159 regs->ARM_r7 = context.arm_r7;
160 regs->ARM_r8 = context.arm_r8;
161 regs->ARM_r9 = context.arm_r9;
162 regs->ARM_r10 = context.arm_r10;
163 regs->ARM_fp = context.arm_fp;
164 regs->ARM_ip = context.arm_ip;
165 regs->ARM_sp = context.arm_sp;
166 regs->ARM_lr = context.arm_lr;
167 regs->ARM_pc = context.arm_pc;
168 regs->ARM_cpsr = context.arm_cpsr;
169 }
170
171 err |= !valid_user_regs(regs);
172
173 aux = (char __user *) sf->uc.uc_regspace;
174#ifdef CONFIG_IWMMXT
175 if (err == 0)
176 err |= restore_iwmmxt_context(&aux);
177#endif
178#ifdef CONFIG_VFP
179 if (err == 0)
180 err |= restore_vfp_context(&aux);
181#endif
182
183 return err;
184}
185
186asmlinkage int sys_sigreturn(struct pt_regs *regs)
187{
188 struct sigframe __user *frame;
189
190 /* Always make any pending restarted system calls return -EINTR */
191 current->restart_block.fn = do_no_restart_syscall;
192
193 /*
194 * Since we stacked the signal on a 64-bit boundary,
195 * then 'sp' should be word aligned here. If it's
196 * not, then the user is trying to mess with us.
197 */
198 if (regs->ARM_sp & 7)
199 goto badframe;
200
201 frame = (struct sigframe __user *)regs->ARM_sp;
202
203 if (!access_ok(frame, sizeof (*frame)))
204 goto badframe;
205
206 if (restore_sigframe(regs, frame))
207 goto badframe;
208
209 return regs->ARM_r0;
210
211badframe:
212 force_sig(SIGSEGV);
213 return 0;
214}
215
216asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
217{
218 struct rt_sigframe __user *frame;
219
220 /* Always make any pending restarted system calls return -EINTR */
221 current->restart_block.fn = do_no_restart_syscall;
222
223 /*
224 * Since we stacked the signal on a 64-bit boundary,
225 * then 'sp' should be word aligned here. If it's
226 * not, then the user is trying to mess with us.
227 */
228 if (regs->ARM_sp & 7)
229 goto badframe;
230
231 frame = (struct rt_sigframe __user *)regs->ARM_sp;
232
233 if (!access_ok(frame, sizeof (*frame)))
234 goto badframe;
235
236 if (restore_sigframe(regs, &frame->sig))
237 goto badframe;
238
239 if (restore_altstack(&frame->sig.uc.uc_stack))
240 goto badframe;
241
242 return regs->ARM_r0;
243
244badframe:
245 force_sig(SIGSEGV);
246 return 0;
247}
248
249static int
250setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
251{
252 struct aux_sigframe __user *aux;
253 struct sigcontext context;
254 int err = 0;
255
256 context = (struct sigcontext) {
257 .arm_r0 = regs->ARM_r0,
258 .arm_r1 = regs->ARM_r1,
259 .arm_r2 = regs->ARM_r2,
260 .arm_r3 = regs->ARM_r3,
261 .arm_r4 = regs->ARM_r4,
262 .arm_r5 = regs->ARM_r5,
263 .arm_r6 = regs->ARM_r6,
264 .arm_r7 = regs->ARM_r7,
265 .arm_r8 = regs->ARM_r8,
266 .arm_r9 = regs->ARM_r9,
267 .arm_r10 = regs->ARM_r10,
268 .arm_fp = regs->ARM_fp,
269 .arm_ip = regs->ARM_ip,
270 .arm_sp = regs->ARM_sp,
271 .arm_lr = regs->ARM_lr,
272 .arm_pc = regs->ARM_pc,
273 .arm_cpsr = regs->ARM_cpsr,
274
275 .trap_no = current->thread.trap_no,
276 .error_code = current->thread.error_code,
277 .fault_address = current->thread.address,
278 .oldmask = set->sig[0],
279 };
280
281 err |= __copy_to_user(&sf->uc.uc_mcontext, &context, sizeof(context));
282
283 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
284
285 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
286#ifdef CONFIG_IWMMXT
287 if (err == 0)
288 err |= preserve_iwmmxt_context(&aux->iwmmxt);
289#endif
290#ifdef CONFIG_VFP
291 if (err == 0)
292 err |= preserve_vfp_context(&aux->vfp);
293#endif
294 err |= __put_user(0, &aux->end_magic);
295
296 return err;
297}
298
299static inline void __user *
300get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
301{
302 unsigned long sp = sigsp(regs->ARM_sp, ksig);
303 void __user *frame;
304
305 /*
306 * ATPCS B01 mandates 8-byte alignment
307 */
308 frame = (void __user *)((sp - framesize) & ~7);
309
310 /*
311 * Check that we can actually write to the signal frame.
312 */
313 if (!access_ok(frame, framesize))
314 frame = NULL;
315
316 return frame;
317}
318
319static int
320setup_return(struct pt_regs *regs, struct ksignal *ksig,
321 unsigned long __user *rc, void __user *frame)
322{
323 unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
324 unsigned long handler_fdpic_GOT = 0;
325 unsigned long retcode;
326 unsigned int idx, thumb = 0;
327 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
328 bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&
329 (current->personality & FDPIC_FUNCPTRS);
330
331 if (fdpic) {
332 unsigned long __user *fdpic_func_desc =
333 (unsigned long __user *)handler;
334 if (__get_user(handler, &fdpic_func_desc[0]) ||
335 __get_user(handler_fdpic_GOT, &fdpic_func_desc[1]))
336 return 1;
337 }
338
339 cpsr |= PSR_ENDSTATE;
340
341 /*
342 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
343 */
344 if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
345 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
346
347#ifdef CONFIG_ARM_THUMB
348 if (elf_hwcap & HWCAP_THUMB) {
349 /*
350 * The LSB of the handler determines if we're going to
351 * be using THUMB or ARM mode for this signal handler.
352 */
353 thumb = handler & 1;
354
355 /*
356 * Clear the If-Then Thumb-2 execution state. ARM spec
357 * requires this to be all 000s in ARM mode. Snapdragon
358 * S4/Krait misbehaves on a Thumb=>ARM signal transition
359 * without this.
360 *
361 * We must do this whenever we are running on a Thumb-2
362 * capable CPU, which includes ARMv6T2. However, we elect
363 * to always do this to simplify the code; this field is
364 * marked UNK/SBZP for older architectures.
365 */
366 cpsr &= ~PSR_IT_MASK;
367
368 if (thumb) {
369 cpsr |= PSR_T_BIT;
370 } else
371 cpsr &= ~PSR_T_BIT;
372 }
373#endif
374
375 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
376 retcode = (unsigned long)ksig->ka.sa.sa_restorer;
377 if (fdpic) {
378 /*
379 * We need code to load the function descriptor.
380 * That code follows the standard sigreturn code
381 * (6 words), and is made of 3 + 2 words for each
382 * variant. The 4th copied word is the actual FD
383 * address that the assembly code expects.
384 */
385 idx = 6 + thumb * 3;
386 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
387 idx += 5;
388 if (__put_user(sigreturn_codes[idx], rc ) ||
389 __put_user(sigreturn_codes[idx+1], rc+1) ||
390 __put_user(sigreturn_codes[idx+2], rc+2) ||
391 __put_user(retcode, rc+3))
392 return 1;
393 goto rc_finish;
394 }
395 } else {
396 idx = thumb << 1;
397 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
398 idx += 3;
399
400 /*
401 * Put the sigreturn code on the stack no matter which return
402 * mechanism we use in order to remain ABI compliant
403 */
404 if (__put_user(sigreturn_codes[idx], rc) ||
405 __put_user(sigreturn_codes[idx+1], rc+1))
406 return 1;
407
408rc_finish:
409#ifdef CONFIG_MMU
410 if (cpsr & MODE32_BIT) {
411 struct mm_struct *mm = current->mm;
412
413 /*
414 * 32-bit code can use the signal return page
415 * except when the MPU has protected the vectors
416 * page from PL0
417 */
418 retcode = mm->context.sigpage + signal_return_offset +
419 (idx << 2) + thumb;
420 } else
421#endif
422 {
423 /*
424 * Ensure that the instruction cache sees
425 * the return code written onto the stack.
426 */
427 flush_icache_range((unsigned long)rc,
428 (unsigned long)(rc + 3));
429
430 retcode = ((unsigned long)rc) + thumb;
431 }
432 }
433
434 regs->ARM_r0 = ksig->sig;
435 regs->ARM_sp = (unsigned long)frame;
436 regs->ARM_lr = retcode;
437 regs->ARM_pc = handler;
438 if (fdpic)
439 regs->ARM_r9 = handler_fdpic_GOT;
440 regs->ARM_cpsr = cpsr;
441
442 return 0;
443}
444
445static int
446setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
447{
448 struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
449 int err = 0;
450
451 if (!frame)
452 return 1;
453
454 /*
455 * Set uc.uc_flags to a value which sc.trap_no would never have.
456 */
457 err = __put_user(0x5ac3c35a, &frame->uc.uc_flags);
458
459 err |= setup_sigframe(frame, regs, set);
460 if (err == 0)
461 err = setup_return(regs, ksig, frame->retcode, frame);
462
463 return err;
464}
465
466static int
467setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
468{
469 struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
470 int err = 0;
471
472 if (!frame)
473 return 1;
474
475 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
476
477 err |= __put_user(0, &frame->sig.uc.uc_flags);
478 err |= __put_user(NULL, &frame->sig.uc.uc_link);
479
480 err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
481 err |= setup_sigframe(&frame->sig, regs, set);
482 if (err == 0)
483 err = setup_return(regs, ksig, frame->sig.retcode, frame);
484
485 if (err == 0) {
486 /*
487 * For realtime signals we must also set the second and third
488 * arguments for the signal handler.
489 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
490 */
491 regs->ARM_r1 = (unsigned long)&frame->info;
492 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
493 }
494
495 return err;
496}
497
498/*
499 * OK, we're invoking a handler
500 */
501static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
502{
503 sigset_t *oldset = sigmask_to_save();
504 int ret;
505
506 /*
507 * Perform fixup for the pre-signal frame.
508 */
509 rseq_signal_deliver(ksig, regs);
510
511 /*
512 * Set up the stack frame
513 */
514 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
515 ret = setup_rt_frame(ksig, oldset, regs);
516 else
517 ret = setup_frame(ksig, oldset, regs);
518
519 /*
520 * Check that the resulting registers are actually sane.
521 */
522 ret |= !valid_user_regs(regs);
523
524 signal_setup_done(ret, ksig, 0);
525}
526
527/*
528 * Note that 'init' is a special process: it doesn't get signals it doesn't
529 * want to handle. Thus you cannot kill init even with a SIGKILL even by
530 * mistake.
531 *
532 * Note that we go through the signals twice: once to check the signals that
533 * the kernel can handle, and then we build all the user-level signal handling
534 * stack-frames in one go after that.
535 */
536static int do_signal(struct pt_regs *regs, int syscall)
537{
538 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
539 struct ksignal ksig;
540 int restart = 0;
541
542 /*
543 * If we were from a system call, check for system call restarting...
544 */
545 if (syscall) {
546 continue_addr = regs->ARM_pc;
547 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
548 retval = regs->ARM_r0;
549
550 /*
551 * Prepare for system call restart. We do this here so that a
552 * debugger will see the already changed PSW.
553 */
554 switch (retval) {
555 case -ERESTART_RESTARTBLOCK:
556 restart -= 2;
557 fallthrough;
558 case -ERESTARTNOHAND:
559 case -ERESTARTSYS:
560 case -ERESTARTNOINTR:
561 restart++;
562 regs->ARM_r0 = regs->ARM_ORIG_r0;
563 regs->ARM_pc = restart_addr;
564 break;
565 }
566 }
567
568 /*
569 * Get the signal to deliver. When running under ptrace, at this
570 * point the debugger may change all our registers ...
571 */
572 /*
573 * Depending on the signal settings we may need to revert the
574 * decision to restart the system call. But skip this if a
575 * debugger has chosen to restart at a different PC.
576 */
577 if (get_signal(&ksig)) {
578 /* handler */
579 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
580 if (retval == -ERESTARTNOHAND ||
581 retval == -ERESTART_RESTARTBLOCK
582 || (retval == -ERESTARTSYS
583 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
584 regs->ARM_r0 = -EINTR;
585 regs->ARM_pc = continue_addr;
586 }
587 }
588 handle_signal(&ksig, regs);
589 } else {
590 /* no handler */
591 restore_saved_sigmask();
592 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
593 regs->ARM_pc = continue_addr;
594 return restart;
595 }
596 }
597 return 0;
598}
599
600asmlinkage int
601do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
602{
603 /*
604 * The assembly code enters us with IRQs off, but it hasn't
605 * informed the tracing code of that for efficiency reasons.
606 * Update the trace code with the current status.
607 */
608 trace_hardirqs_off();
609 do {
610 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
611 schedule();
612 } else {
613 if (unlikely(!user_mode(regs)))
614 return 0;
615 local_irq_enable();
616 if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
617 int restart = do_signal(regs, syscall);
618 if (unlikely(restart)) {
619 /*
620 * Restart without handlers.
621 * Deal with it without leaving
622 * the kernel space.
623 */
624 return restart;
625 }
626 syscall = 0;
627 } else if (thread_flags & _TIF_UPROBE) {
628 uprobe_notify_resume(regs);
629 } else {
630 resume_user_mode_work(regs);
631 }
632 }
633 local_irq_disable();
634 thread_flags = read_thread_flags();
635 } while (thread_flags & _TIF_WORK_MASK);
636 return 0;
637}
638
639struct page *get_signal_page(void)
640{
641 unsigned long ptr;
642 unsigned offset;
643 struct page *page;
644 void *addr;
645
646 page = alloc_pages(GFP_KERNEL, 0);
647
648 if (!page)
649 return NULL;
650
651 addr = page_address(page);
652
653 /* Poison the entire page */
654 memset32(addr, __opcode_to_mem_arm(0xe7fddef1),
655 PAGE_SIZE / sizeof(u32));
656
657 /* Give the signal return code some randomness */
658 offset = 0x200 + (get_random_u16() & 0x7fc);
659 signal_return_offset = offset;
660
661 /* Copy signal return handlers into the page */
662 memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
663
664 /* Flush out all instructions in this page */
665 ptr = (unsigned long)addr;
666 flush_icache_range(ptr, ptr + PAGE_SIZE);
667
668 return page;
669}
670
671#ifdef CONFIG_DEBUG_RSEQ
672asmlinkage void do_rseq_syscall(struct pt_regs *regs)
673{
674 rseq_syscall(regs);
675}
676#endif
677
678/*
679 * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
680 * changes likely come with new fields that should be added below.
681 */
682static_assert(NSIGILL == 11);
683static_assert(NSIGFPE == 15);
684static_assert(NSIGSEGV == 9);
685static_assert(NSIGBUS == 5);
686static_assert(NSIGTRAP == 6);
687static_assert(NSIGCHLD == 6);
688static_assert(NSIGSYS == 2);
689static_assert(sizeof(siginfo_t) == 128);
690static_assert(__alignof__(siginfo_t) == 4);
691static_assert(offsetof(siginfo_t, si_signo) == 0x00);
692static_assert(offsetof(siginfo_t, si_errno) == 0x04);
693static_assert(offsetof(siginfo_t, si_code) == 0x08);
694static_assert(offsetof(siginfo_t, si_pid) == 0x0c);
695static_assert(offsetof(siginfo_t, si_uid) == 0x10);
696static_assert(offsetof(siginfo_t, si_tid) == 0x0c);
697static_assert(offsetof(siginfo_t, si_overrun) == 0x10);
698static_assert(offsetof(siginfo_t, si_status) == 0x14);
699static_assert(offsetof(siginfo_t, si_utime) == 0x18);
700static_assert(offsetof(siginfo_t, si_stime) == 0x1c);
701static_assert(offsetof(siginfo_t, si_value) == 0x14);
702static_assert(offsetof(siginfo_t, si_int) == 0x14);
703static_assert(offsetof(siginfo_t, si_ptr) == 0x14);
704static_assert(offsetof(siginfo_t, si_addr) == 0x0c);
705static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x10);
706static_assert(offsetof(siginfo_t, si_lower) == 0x14);
707static_assert(offsetof(siginfo_t, si_upper) == 0x18);
708static_assert(offsetof(siginfo_t, si_pkey) == 0x14);
709static_assert(offsetof(siginfo_t, si_perf_data) == 0x10);
710static_assert(offsetof(siginfo_t, si_perf_type) == 0x14);
711static_assert(offsetof(siginfo_t, si_perf_flags) == 0x18);
712static_assert(offsetof(siginfo_t, si_band) == 0x0c);
713static_assert(offsetof(siginfo_t, si_fd) == 0x10);
714static_assert(offsetof(siginfo_t, si_call_addr) == 0x0c);
715static_assert(offsetof(siginfo_t, si_syscall) == 0x10);
716static_assert(offsetof(siginfo_t, si_arch) == 0x14);