2 * linux/arch/arm/kernel/signal.c
4 * Copyright (C) 1995-2009 Russell King
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.
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>
18 #include <asm/cacheflush.h>
19 #include <asm/ucontext.h>
20 #include <asm/unistd.h>
25 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
28 * For ARM syscalls, we encode the syscall number into the instruction.
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)
35 * With EABI, the syscall number has to be loaded into r7.
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))
41 * For Thumb syscalls, we pass the syscall number via r7. We therefore
42 * need two 16-bit instructions.
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))
47 const 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,
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
59 const unsigned long syscall_restart_code[2] = {
60 SWI_SYS_RESTART, /* swi __NR_restart_syscall */
61 0xe49df004, /* ldr pc, [sp], #4 */
65 * atomically swap in the new signal mask, and wait for a signal.
67 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
71 current->saved_sigmask = current->blocked;
74 siginitset(&blocked, mask);
75 set_current_blocked(&blocked);
77 current->state = TASK_INTERRUPTIBLE;
79 set_restore_sigmask();
80 return -ERESTARTNOHAND;
84 sys_sigaction(int sig, const struct old_sigaction __user *act,
85 struct old_sigaction __user *oact)
87 struct k_sigaction new_ka, old_ka;
92 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
93 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
94 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
96 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
97 __get_user(mask, &act->sa_mask);
98 siginitset(&new_ka.sa.sa_mask, mask);
101 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
104 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
105 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
106 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
108 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
109 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
116 static int preserve_crunch_context(struct crunch_sigframe __user *frame)
118 char kbuf[sizeof(*frame) + 8];
119 struct crunch_sigframe *kframe;
121 /* the crunch context must be 64 bit aligned */
122 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
123 kframe->magic = CRUNCH_MAGIC;
124 kframe->size = CRUNCH_STORAGE_SIZE;
125 crunch_task_copy(current_thread_info(), &kframe->storage);
126 return __copy_to_user(frame, kframe, sizeof(*frame));
129 static int restore_crunch_context(struct crunch_sigframe __user *frame)
131 char kbuf[sizeof(*frame) + 8];
132 struct crunch_sigframe *kframe;
134 /* the crunch context must be 64 bit aligned */
135 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
136 if (__copy_from_user(kframe, frame, sizeof(*frame)))
138 if (kframe->magic != CRUNCH_MAGIC ||
139 kframe->size != CRUNCH_STORAGE_SIZE)
141 crunch_task_restore(current_thread_info(), &kframe->storage);
148 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
150 char kbuf[sizeof(*frame) + 8];
151 struct iwmmxt_sigframe *kframe;
153 /* the iWMMXt context must be 64 bit aligned */
154 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
155 kframe->magic = IWMMXT_MAGIC;
156 kframe->size = IWMMXT_STORAGE_SIZE;
157 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
158 return __copy_to_user(frame, kframe, sizeof(*frame));
161 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
163 char kbuf[sizeof(*frame) + 8];
164 struct iwmmxt_sigframe *kframe;
166 /* the iWMMXt context must be 64 bit aligned */
167 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
168 if (__copy_from_user(kframe, frame, sizeof(*frame)))
170 if (kframe->magic != IWMMXT_MAGIC ||
171 kframe->size != IWMMXT_STORAGE_SIZE)
173 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
181 static int preserve_vfp_context(struct vfp_sigframe __user *frame)
183 const unsigned long magic = VFP_MAGIC;
184 const unsigned long size = VFP_STORAGE_SIZE;
187 __put_user_error(magic, &frame->magic, err);
188 __put_user_error(size, &frame->size, err);
193 return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
196 static int restore_vfp_context(struct vfp_sigframe __user *frame)
202 __get_user_error(magic, &frame->magic, err);
203 __get_user_error(size, &frame->size, err);
207 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
210 return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
216 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
220 unsigned long retcode[2];
228 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
230 struct aux_sigframe __user *aux;
234 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
236 sigdelsetmask(&set, ~_BLOCKABLE);
237 set_current_blocked(&set);
240 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
241 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
242 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
243 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
244 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
245 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
246 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
247 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
248 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
249 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
250 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
251 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
252 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
253 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
254 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
255 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
256 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
258 err |= !valid_user_regs(regs);
260 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
263 err |= restore_crunch_context(&aux->crunch);
266 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
267 err |= restore_iwmmxt_context(&aux->iwmmxt);
271 err |= restore_vfp_context(&aux->vfp);
277 asmlinkage int sys_sigreturn(struct pt_regs *regs)
279 struct sigframe __user *frame;
281 /* Always make any pending restarted system calls return -EINTR */
282 current_thread_info()->restart_block.fn = do_no_restart_syscall;
285 * Since we stacked the signal on a 64-bit boundary,
286 * then 'sp' should be word aligned here. If it's
287 * not, then the user is trying to mess with us.
289 if (regs->ARM_sp & 7)
292 frame = (struct sigframe __user *)regs->ARM_sp;
294 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
297 if (restore_sigframe(regs, frame))
303 force_sig(SIGSEGV, current);
307 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
309 struct rt_sigframe __user *frame;
311 /* Always make any pending restarted system calls return -EINTR */
312 current_thread_info()->restart_block.fn = do_no_restart_syscall;
315 * Since we stacked the signal on a 64-bit boundary,
316 * then 'sp' should be word aligned here. If it's
317 * not, then the user is trying to mess with us.
319 if (regs->ARM_sp & 7)
322 frame = (struct rt_sigframe __user *)regs->ARM_sp;
324 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
327 if (restore_sigframe(regs, &frame->sig))
330 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
336 force_sig(SIGSEGV, current);
341 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
343 struct aux_sigframe __user *aux;
346 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
347 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
348 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
349 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
350 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
351 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
352 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
353 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
354 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
355 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
356 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
357 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
358 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
359 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
360 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
361 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
362 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
364 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
365 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
366 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
367 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
369 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
371 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
374 err |= preserve_crunch_context(&aux->crunch);
377 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
378 err |= preserve_iwmmxt_context(&aux->iwmmxt);
382 err |= preserve_vfp_context(&aux->vfp);
384 __put_user_error(0, &aux->end_magic, err);
389 static inline void __user *
390 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
392 unsigned long sp = regs->ARM_sp;
396 * This is the X/Open sanctioned signal stack switching.
398 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
399 sp = current->sas_ss_sp + current->sas_ss_size;
402 * ATPCS B01 mandates 8-byte alignment
404 frame = (void __user *)((sp - framesize) & ~7);
407 * Check that we can actually write to the signal frame.
409 if (!access_ok(VERIFY_WRITE, frame, framesize))
416 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
417 unsigned long __user *rc, void __user *frame, int usig)
419 unsigned long handler = (unsigned long)ka->sa.sa_handler;
420 unsigned long retcode;
422 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
424 cpsr |= PSR_ENDSTATE;
427 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
429 if (ka->sa.sa_flags & SA_THIRTYTWO)
430 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
432 #ifdef CONFIG_ARM_THUMB
433 if (elf_hwcap & HWCAP_THUMB) {
435 * The LSB of the handler determines if we're going to
436 * be using THUMB or ARM mode for this signal handler.
442 #if __LINUX_ARM_ARCH__ >= 7
443 /* clear the If-Then Thumb-2 execution state */
444 cpsr &= ~PSR_IT_MASK;
451 if (ka->sa.sa_flags & SA_RESTORER) {
452 retcode = (unsigned long)ka->sa.sa_restorer;
454 unsigned int idx = thumb << 1;
456 if (ka->sa.sa_flags & SA_SIGINFO)
459 if (__put_user(sigreturn_codes[idx], rc) ||
460 __put_user(sigreturn_codes[idx+1], rc+1))
463 if (cpsr & MODE32_BIT) {
465 * 32-bit code can use the new high-page
466 * signal return code support.
468 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
471 * Ensure that the instruction cache sees
472 * the return code written onto the stack.
474 flush_icache_range((unsigned long)rc,
475 (unsigned long)(rc + 2));
477 retcode = ((unsigned long)rc) + thumb;
482 regs->ARM_sp = (unsigned long)frame;
483 regs->ARM_lr = retcode;
484 regs->ARM_pc = handler;
485 regs->ARM_cpsr = cpsr;
491 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
493 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
500 * Set uc.uc_flags to a value which sc.trap_no would never have.
502 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
504 err |= setup_sigframe(frame, regs, set);
506 err = setup_return(regs, ka, frame->retcode, frame, usig);
512 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
513 sigset_t *set, struct pt_regs *regs)
515 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
522 err |= copy_siginfo_to_user(&frame->info, info);
524 __put_user_error(0, &frame->sig.uc.uc_flags, err);
525 __put_user_error(NULL, &frame->sig.uc.uc_link, err);
527 memset(&stack, 0, sizeof(stack));
528 stack.ss_sp = (void __user *)current->sas_ss_sp;
529 stack.ss_flags = sas_ss_flags(regs->ARM_sp);
530 stack.ss_size = current->sas_ss_size;
531 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
533 err |= setup_sigframe(&frame->sig, regs, set);
535 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
539 * For realtime signals we must also set the second and third
540 * arguments for the signal handler.
541 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
543 regs->ARM_r1 = (unsigned long)&frame->info;
544 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
551 * OK, we're invoking a handler
554 handle_signal(unsigned long sig, struct k_sigaction *ka,
555 siginfo_t *info, sigset_t *oldset,
556 struct pt_regs * regs)
558 struct thread_info *thread = current_thread_info();
559 struct task_struct *tsk = current;
564 * translate the signal
566 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
567 usig = thread->exec_domain->signal_invmap[usig];
570 * Set up the stack frame
572 if (ka->sa.sa_flags & SA_SIGINFO)
573 ret = setup_rt_frame(usig, ka, info, oldset, regs);
575 ret = setup_frame(usig, ka, oldset, regs);
578 * Check that the resulting registers are actually sane.
580 ret |= !valid_user_regs(regs);
583 force_sigsegv(sig, tsk);
588 * Block the signal if we were successful.
590 block_sigmask(ka, sig);
592 tracehook_signal_handler(sig, info, ka, regs, 0);
598 * Note that 'init' is a special process: it doesn't get signals it doesn't
599 * want to handle. Thus you cannot kill init even with a SIGKILL even by
602 * Note that we go through the signals twice: once to check the signals that
603 * the kernel can handle, and then we build all the user-level signal handling
604 * stack-frames in one go after that.
606 static void do_signal(struct pt_regs *regs, int syscall)
608 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
609 struct k_sigaction ka;
614 * We want the common case to go fast, which
615 * is why we may in certain cases get here from
616 * kernel mode. Just return without doing anything
619 if (!user_mode(regs))
623 * If we were from a system call, check for system call restarting...
626 continue_addr = regs->ARM_pc;
627 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
628 retval = regs->ARM_r0;
631 * Prepare for system call restart. We do this here so that a
632 * debugger will see the already changed PSW.
635 case -ERESTARTNOHAND:
637 case -ERESTARTNOINTR:
638 regs->ARM_r0 = regs->ARM_ORIG_r0;
639 regs->ARM_pc = restart_addr;
641 case -ERESTART_RESTARTBLOCK:
642 regs->ARM_r0 = -EINTR;
651 * Get the signal to deliver. When running under ptrace, at this
652 * point the debugger may change all our registers ...
654 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
659 * Depending on the signal settings we may need to revert the
660 * decision to restart the system call. But skip this if a
661 * debugger has chosen to restart at a different PC.
663 if (regs->ARM_pc == restart_addr) {
664 if (retval == -ERESTARTNOHAND
665 || (retval == -ERESTARTSYS
666 && !(ka.sa.sa_flags & SA_RESTART))) {
667 regs->ARM_r0 = -EINTR;
668 regs->ARM_pc = continue_addr;
672 if (test_thread_flag(TIF_RESTORE_SIGMASK))
673 oldset = ¤t->saved_sigmask;
675 oldset = ¤t->blocked;
676 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
678 * A signal was successfully delivered; the saved
679 * sigmask will have been stored in the signal frame,
680 * and will be restored by sigreturn, so we can simply
681 * clear the TIF_RESTORE_SIGMASK flag.
683 if (test_thread_flag(TIF_RESTORE_SIGMASK))
684 clear_thread_flag(TIF_RESTORE_SIGMASK);
692 * Handle restarting a different system call. As above,
693 * if a debugger has chosen to restart at a different PC,
694 * ignore the restart.
696 if (retval == -ERESTART_RESTARTBLOCK
697 && regs->ARM_pc == continue_addr) {
698 if (thumb_mode(regs)) {
699 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
702 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
703 regs->ARM_r7 = __NR_restart_syscall;
709 usp = (u32 __user *)regs->ARM_sp;
711 if (put_user(regs->ARM_pc, usp) == 0) {
712 regs->ARM_pc = KERN_RESTART_CODE;
715 force_sigsegv(0, current);
721 /* If there's no signal to deliver, we just put the saved sigmask
724 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
725 clear_thread_flag(TIF_RESTORE_SIGMASK);
726 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
732 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
734 if (thread_flags & _TIF_SIGPENDING)
735 do_signal(regs, syscall);
737 if (thread_flags & _TIF_NOTIFY_RESUME) {
738 clear_thread_flag(TIF_NOTIFY_RESUME);
739 tracehook_notify_resume(regs);
740 if (current->replacement_session_keyring)
741 key_replace_session_keyring();