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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/*
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}
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
18#include <asm/elf.h>
19#include <asm/cacheflush.h>
20#include <asm/traps.h>
21#include <asm/ucontext.h>
22#include <asm/unistd.h>
23#include <asm/vfp.h>
24
25extern const unsigned long sigreturn_codes[7];
26
27static unsigned long signal_return_offset;
28
29#ifdef CONFIG_CRUNCH
30static int preserve_crunch_context(struct crunch_sigframe __user *frame)
31{
32 char kbuf[sizeof(*frame) + 8];
33 struct crunch_sigframe *kframe;
34
35 /* the crunch context must be 64 bit aligned */
36 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
37 kframe->magic = CRUNCH_MAGIC;
38 kframe->size = CRUNCH_STORAGE_SIZE;
39 crunch_task_copy(current_thread_info(), &kframe->storage);
40 return __copy_to_user(frame, kframe, sizeof(*frame));
41}
42
43static int restore_crunch_context(struct crunch_sigframe __user *frame)
44{
45 char kbuf[sizeof(*frame) + 8];
46 struct crunch_sigframe *kframe;
47
48 /* the crunch context must be 64 bit aligned */
49 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
50 if (__copy_from_user(kframe, frame, sizeof(*frame)))
51 return -1;
52 if (kframe->magic != CRUNCH_MAGIC ||
53 kframe->size != CRUNCH_STORAGE_SIZE)
54 return -1;
55 crunch_task_restore(current_thread_info(), &kframe->storage);
56 return 0;
57}
58#endif
59
60#ifdef CONFIG_IWMMXT
61
62static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
63{
64 char kbuf[sizeof(*frame) + 8];
65 struct iwmmxt_sigframe *kframe;
66
67 /* the iWMMXt context must be 64 bit aligned */
68 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
69 kframe->magic = IWMMXT_MAGIC;
70 kframe->size = IWMMXT_STORAGE_SIZE;
71 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
72 return __copy_to_user(frame, kframe, sizeof(*frame));
73}
74
75static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
76{
77 char kbuf[sizeof(*frame) + 8];
78 struct iwmmxt_sigframe *kframe;
79
80 /* the iWMMXt context must be 64 bit aligned */
81 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
82 if (__copy_from_user(kframe, frame, sizeof(*frame)))
83 return -1;
84 if (kframe->magic != IWMMXT_MAGIC ||
85 kframe->size != IWMMXT_STORAGE_SIZE)
86 return -1;
87 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
88 return 0;
89}
90
91#endif
92
93#ifdef CONFIG_VFP
94
95static int preserve_vfp_context(struct vfp_sigframe __user *frame)
96{
97 const unsigned long magic = VFP_MAGIC;
98 const unsigned long size = VFP_STORAGE_SIZE;
99 int err = 0;
100
101 __put_user_error(magic, &frame->magic, err);
102 __put_user_error(size, &frame->size, err);
103
104 if (err)
105 return -EFAULT;
106
107 return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
108}
109
110static int restore_vfp_context(struct vfp_sigframe __user *frame)
111{
112 unsigned long magic;
113 unsigned long size;
114 int err = 0;
115
116 __get_user_error(magic, &frame->magic, err);
117 __get_user_error(size, &frame->size, err);
118
119 if (err)
120 return -EFAULT;
121 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
122 return -EINVAL;
123
124 return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
125}
126
127#endif
128
129/*
130 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
131 */
132struct sigframe {
133 struct ucontext uc;
134 unsigned long retcode[2];
135};
136
137struct rt_sigframe {
138 struct siginfo info;
139 struct sigframe sig;
140};
141
142static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
143{
144 struct aux_sigframe __user *aux;
145 sigset_t set;
146 int err;
147
148 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
149 if (err == 0)
150 set_current_blocked(&set);
151
152 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
153 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
154 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
155 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
156 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
157 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
158 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
159 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
160 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
161 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
162 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
163 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
164 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
165 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
166 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
167 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
168 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
169
170 err |= !valid_user_regs(regs);
171
172 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
173#ifdef CONFIG_CRUNCH
174 if (err == 0)
175 err |= restore_crunch_context(&aux->crunch);
176#endif
177#ifdef CONFIG_IWMMXT
178 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
179 err |= restore_iwmmxt_context(&aux->iwmmxt);
180#endif
181#ifdef CONFIG_VFP
182 if (err == 0)
183 err |= restore_vfp_context(&aux->vfp);
184#endif
185
186 return err;
187}
188
189asmlinkage int sys_sigreturn(struct pt_regs *regs)
190{
191 struct sigframe __user *frame;
192
193 /* Always make any pending restarted system calls return -EINTR */
194 current_thread_info()->restart_block.fn = do_no_restart_syscall;
195
196 /*
197 * Since we stacked the signal on a 64-bit boundary,
198 * then 'sp' should be word aligned here. If it's
199 * not, then the user is trying to mess with us.
200 */
201 if (regs->ARM_sp & 7)
202 goto badframe;
203
204 frame = (struct sigframe __user *)regs->ARM_sp;
205
206 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
207 goto badframe;
208
209 if (restore_sigframe(regs, frame))
210 goto badframe;
211
212 return regs->ARM_r0;
213
214badframe:
215 force_sig(SIGSEGV, current);
216 return 0;
217}
218
219asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
220{
221 struct rt_sigframe __user *frame;
222
223 /* Always make any pending restarted system calls return -EINTR */
224 current_thread_info()->restart_block.fn = do_no_restart_syscall;
225
226 /*
227 * Since we stacked the signal on a 64-bit boundary,
228 * then 'sp' should be word aligned here. If it's
229 * not, then the user is trying to mess with us.
230 */
231 if (regs->ARM_sp & 7)
232 goto badframe;
233
234 frame = (struct rt_sigframe __user *)regs->ARM_sp;
235
236 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
237 goto badframe;
238
239 if (restore_sigframe(regs, &frame->sig))
240 goto badframe;
241
242 if (restore_altstack(&frame->sig.uc.uc_stack))
243 goto badframe;
244
245 return regs->ARM_r0;
246
247badframe:
248 force_sig(SIGSEGV, current);
249 return 0;
250}
251
252static int
253setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
254{
255 struct aux_sigframe __user *aux;
256 int err = 0;
257
258 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
259 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
260 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
261 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
262 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
263 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
264 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
265 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
266 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
267 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
268 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
269 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
270 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
271 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
272 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
273 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
274 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
275
276 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
277 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
278 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
279 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
280
281 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
282
283 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
284#ifdef CONFIG_CRUNCH
285 if (err == 0)
286 err |= preserve_crunch_context(&aux->crunch);
287#endif
288#ifdef CONFIG_IWMMXT
289 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
290 err |= preserve_iwmmxt_context(&aux->iwmmxt);
291#endif
292#ifdef CONFIG_VFP
293 if (err == 0)
294 err |= preserve_vfp_context(&aux->vfp);
295#endif
296 __put_user_error(0, &aux->end_magic, err);
297
298 return err;
299}
300
301static inline void __user *
302get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
303{
304 unsigned long sp = sigsp(regs->ARM_sp, ksig);
305 void __user *frame;
306
307 /*
308 * ATPCS B01 mandates 8-byte alignment
309 */
310 frame = (void __user *)((sp - framesize) & ~7);
311
312 /*
313 * Check that we can actually write to the signal frame.
314 */
315 if (!access_ok(VERIFY_WRITE, frame, framesize))
316 frame = NULL;
317
318 return frame;
319}
320
321/*
322 * translate the signal
323 */
324static inline int map_sig(int sig)
325{
326 struct thread_info *thread = current_thread_info();
327 if (sig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
328 sig = thread->exec_domain->signal_invmap[sig];
329 return sig;
330}
331
332static int
333setup_return(struct pt_regs *regs, struct ksignal *ksig,
334 unsigned long __user *rc, void __user *frame)
335{
336 unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
337 unsigned long retcode;
338 int thumb = 0;
339 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
340
341 cpsr |= PSR_ENDSTATE;
342
343 /*
344 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
345 */
346 if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
347 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
348
349#ifdef CONFIG_ARM_THUMB
350 if (elf_hwcap & HWCAP_THUMB) {
351 /*
352 * The LSB of the handler determines if we're going to
353 * be using THUMB or ARM mode for this signal handler.
354 */
355 thumb = handler & 1;
356
357#if __LINUX_ARM_ARCH__ >= 7
358 /*
359 * Clear the If-Then Thumb-2 execution state
360 * ARM spec requires this to be all 000s in ARM mode
361 * Snapdragon S4/Krait misbehaves on a Thumb=>ARM
362 * signal transition without this.
363 */
364 cpsr &= ~PSR_IT_MASK;
365#endif
366
367 if (thumb) {
368 cpsr |= PSR_T_BIT;
369 } else
370 cpsr &= ~PSR_T_BIT;
371 }
372#endif
373
374 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
375 retcode = (unsigned long)ksig->ka.sa.sa_restorer;
376 } else {
377 unsigned int idx = thumb << 1;
378
379 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
380 idx += 3;
381
382 /*
383 * Put the sigreturn code on the stack no matter which return
384 * mechanism we use in order to remain ABI compliant
385 */
386 if (__put_user(sigreturn_codes[idx], rc) ||
387 __put_user(sigreturn_codes[idx+1], rc+1))
388 return 1;
389
390#ifdef CONFIG_MMU
391 if (cpsr & MODE32_BIT) {
392 struct mm_struct *mm = current->mm;
393
394 /*
395 * 32-bit code can use the signal return page
396 * except when the MPU has protected the vectors
397 * page from PL0
398 */
399 retcode = mm->context.sigpage + signal_return_offset +
400 (idx << 2) + thumb;
401 } else
402#endif
403 {
404 /*
405 * Ensure that the instruction cache sees
406 * the return code written onto the stack.
407 */
408 flush_icache_range((unsigned long)rc,
409 (unsigned long)(rc + 2));
410
411 retcode = ((unsigned long)rc) + thumb;
412 }
413 }
414
415 regs->ARM_r0 = map_sig(ksig->sig);
416 regs->ARM_sp = (unsigned long)frame;
417 regs->ARM_lr = retcode;
418 regs->ARM_pc = handler;
419 regs->ARM_cpsr = cpsr;
420
421 return 0;
422}
423
424static int
425setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
426{
427 struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
428 int err = 0;
429
430 if (!frame)
431 return 1;
432
433 /*
434 * Set uc.uc_flags to a value which sc.trap_no would never have.
435 */
436 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
437
438 err |= setup_sigframe(frame, regs, set);
439 if (err == 0)
440 err = setup_return(regs, ksig, frame->retcode, frame);
441
442 return err;
443}
444
445static int
446setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
447{
448 struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
449 int err = 0;
450
451 if (!frame)
452 return 1;
453
454 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
455
456 __put_user_error(0, &frame->sig.uc.uc_flags, err);
457 __put_user_error(NULL, &frame->sig.uc.uc_link, err);
458
459 err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
460 err |= setup_sigframe(&frame->sig, regs, set);
461 if (err == 0)
462 err = setup_return(regs, ksig, frame->sig.retcode, frame);
463
464 if (err == 0) {
465 /*
466 * For realtime signals we must also set the second and third
467 * arguments for the signal handler.
468 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
469 */
470 regs->ARM_r1 = (unsigned long)&frame->info;
471 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
472 }
473
474 return err;
475}
476
477/*
478 * OK, we're invoking a handler
479 */
480static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
481{
482 sigset_t *oldset = sigmask_to_save();
483 int ret;
484
485 /*
486 * Set up the stack frame
487 */
488 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
489 ret = setup_rt_frame(ksig, oldset, regs);
490 else
491 ret = setup_frame(ksig, oldset, regs);
492
493 /*
494 * Check that the resulting registers are actually sane.
495 */
496 ret |= !valid_user_regs(regs);
497
498 signal_setup_done(ret, ksig, 0);
499}
500
501/*
502 * Note that 'init' is a special process: it doesn't get signals it doesn't
503 * want to handle. Thus you cannot kill init even with a SIGKILL even by
504 * mistake.
505 *
506 * Note that we go through the signals twice: once to check the signals that
507 * the kernel can handle, and then we build all the user-level signal handling
508 * stack-frames in one go after that.
509 */
510static int do_signal(struct pt_regs *regs, int syscall)
511{
512 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
513 struct ksignal ksig;
514 int restart = 0;
515
516 /*
517 * If we were from a system call, check for system call restarting...
518 */
519 if (syscall) {
520 continue_addr = regs->ARM_pc;
521 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
522 retval = regs->ARM_r0;
523
524 /*
525 * Prepare for system call restart. We do this here so that a
526 * debugger will see the already changed PSW.
527 */
528 switch (retval) {
529 case -ERESTART_RESTARTBLOCK:
530 restart -= 2;
531 case -ERESTARTNOHAND:
532 case -ERESTARTSYS:
533 case -ERESTARTNOINTR:
534 restart++;
535 regs->ARM_r0 = regs->ARM_ORIG_r0;
536 regs->ARM_pc = restart_addr;
537 break;
538 }
539 }
540
541 /*
542 * Get the signal to deliver. When running under ptrace, at this
543 * point the debugger may change all our registers ...
544 */
545 /*
546 * Depending on the signal settings we may need to revert the
547 * decision to restart the system call. But skip this if a
548 * debugger has chosen to restart at a different PC.
549 */
550 if (get_signal(&ksig)) {
551 /* handler */
552 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
553 if (retval == -ERESTARTNOHAND ||
554 retval == -ERESTART_RESTARTBLOCK
555 || (retval == -ERESTARTSYS
556 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
557 regs->ARM_r0 = -EINTR;
558 regs->ARM_pc = continue_addr;
559 }
560 }
561 handle_signal(&ksig, regs);
562 } else {
563 /* no handler */
564 restore_saved_sigmask();
565 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
566 regs->ARM_pc = continue_addr;
567 return restart;
568 }
569 }
570 return 0;
571}
572
573asmlinkage int
574do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
575{
576 do {
577 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
578 schedule();
579 } else {
580 if (unlikely(!user_mode(regs)))
581 return 0;
582 local_irq_enable();
583 if (thread_flags & _TIF_SIGPENDING) {
584 int restart = do_signal(regs, syscall);
585 if (unlikely(restart)) {
586 /*
587 * Restart without handlers.
588 * Deal with it without leaving
589 * the kernel space.
590 */
591 return restart;
592 }
593 syscall = 0;
594 } else if (thread_flags & _TIF_UPROBE) {
595 clear_thread_flag(TIF_UPROBE);
596 uprobe_notify_resume(regs);
597 } else {
598 clear_thread_flag(TIF_NOTIFY_RESUME);
599 tracehook_notify_resume(regs);
600 }
601 }
602 local_irq_disable();
603 thread_flags = current_thread_info()->flags;
604 } while (thread_flags & _TIF_WORK_MASK);
605 return 0;
606}
607
608struct page *get_signal_page(void)
609{
610 unsigned long ptr;
611 unsigned offset;
612 struct page *page;
613 void *addr;
614
615 page = alloc_pages(GFP_KERNEL, 0);
616
617 if (!page)
618 return NULL;
619
620 addr = page_address(page);
621
622 /* Give the signal return code some randomness */
623 offset = 0x200 + (get_random_int() & 0x7fc);
624 signal_return_offset = offset;
625
626 /*
627 * Copy signal return handlers into the vector page, and
628 * set sigreturn to be a pointer to these.
629 */
630 memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
631
632 ptr = (unsigned long)addr + offset;
633 flush_icache_range(ptr, ptr + sizeof(sigreturn_codes));
634
635 return page;
636}