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