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>
26 * For ARM syscalls, we encode the syscall number into the instruction.
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)
33 * With EABI, the syscall number has to be loaded into r7.
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))
39 * For Thumb syscalls, we pass the syscall number via r7. We therefore
40 * need two 16-bit instructions.
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))
45 const 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,
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
57 const unsigned long syscall_restart_code[2] = {
58 SWI_SYS_RESTART, /* swi __NR_restart_syscall */
59 0xe49df004, /* ldr pc, [sp], #4 */
63 * atomically swap in the new signal mask, and wait for a signal.
65 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
68 siginitset(&blocked, mask);
69 return sigsuspend(&blocked);
73 sys_sigaction(int sig, const struct old_sigaction __user *act,
74 struct old_sigaction __user *oact)
76 struct k_sigaction new_ka, old_ka;
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))
87 siginitset(&new_ka.sa.sa_mask, mask);
90 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
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))
105 static int preserve_crunch_context(struct crunch_sigframe __user *frame)
107 char kbuf[sizeof(*frame) + 8];
108 struct crunch_sigframe *kframe;
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));
118 static int restore_crunch_context(struct crunch_sigframe __user *frame)
120 char kbuf[sizeof(*frame) + 8];
121 struct crunch_sigframe *kframe;
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)))
127 if (kframe->magic != CRUNCH_MAGIC ||
128 kframe->size != CRUNCH_STORAGE_SIZE)
130 crunch_task_restore(current_thread_info(), &kframe->storage);
137 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
139 char kbuf[sizeof(*frame) + 8];
140 struct iwmmxt_sigframe *kframe;
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));
150 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
152 char kbuf[sizeof(*frame) + 8];
153 struct iwmmxt_sigframe *kframe;
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)))
159 if (kframe->magic != IWMMXT_MAGIC ||
160 kframe->size != IWMMXT_STORAGE_SIZE)
162 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
170 static int preserve_vfp_context(struct vfp_sigframe __user *frame)
172 const unsigned long magic = VFP_MAGIC;
173 const unsigned long size = VFP_STORAGE_SIZE;
176 __put_user_error(magic, &frame->magic, err);
177 __put_user_error(size, &frame->size, err);
182 return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
185 static int restore_vfp_context(struct vfp_sigframe __user *frame)
191 __get_user_error(magic, &frame->magic, err);
192 __get_user_error(size, &frame->size, err);
196 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
199 return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
205 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
209 unsigned long retcode[2];
217 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
219 struct aux_sigframe __user *aux;
223 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
225 set_current_blocked(&set);
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);
245 err |= !valid_user_regs(regs);
247 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
250 err |= restore_crunch_context(&aux->crunch);
253 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
254 err |= restore_iwmmxt_context(&aux->iwmmxt);
258 err |= restore_vfp_context(&aux->vfp);
264 asmlinkage int sys_sigreturn(struct pt_regs *regs)
266 struct sigframe __user *frame;
268 /* Always make any pending restarted system calls return -EINTR */
269 current_thread_info()->restart_block.fn = do_no_restart_syscall;
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.
276 if (regs->ARM_sp & 7)
279 frame = (struct sigframe __user *)regs->ARM_sp;
281 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
284 if (restore_sigframe(regs, frame))
290 force_sig(SIGSEGV, current);
294 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
296 struct rt_sigframe __user *frame;
298 /* Always make any pending restarted system calls return -EINTR */
299 current_thread_info()->restart_block.fn = do_no_restart_syscall;
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.
306 if (regs->ARM_sp & 7)
309 frame = (struct rt_sigframe __user *)regs->ARM_sp;
311 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
314 if (restore_sigframe(regs, &frame->sig))
317 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
323 force_sig(SIGSEGV, current);
328 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
330 struct aux_sigframe __user *aux;
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);
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);
356 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
358 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
361 err |= preserve_crunch_context(&aux->crunch);
364 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
365 err |= preserve_iwmmxt_context(&aux->iwmmxt);
369 err |= preserve_vfp_context(&aux->vfp);
371 __put_user_error(0, &aux->end_magic, err);
376 static inline void __user *
377 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
379 unsigned long sp = regs->ARM_sp;
383 * This is the X/Open sanctioned signal stack switching.
385 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
386 sp = current->sas_ss_sp + current->sas_ss_size;
389 * ATPCS B01 mandates 8-byte alignment
391 frame = (void __user *)((sp - framesize) & ~7);
394 * Check that we can actually write to the signal frame.
396 if (!access_ok(VERIFY_WRITE, frame, framesize))
403 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
404 unsigned long __user *rc, void __user *frame, int usig)
406 unsigned long handler = (unsigned long)ka->sa.sa_handler;
407 unsigned long retcode;
409 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
411 cpsr |= PSR_ENDSTATE;
414 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
416 if (ka->sa.sa_flags & SA_THIRTYTWO)
417 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
419 #ifdef CONFIG_ARM_THUMB
420 if (elf_hwcap & HWCAP_THUMB) {
422 * The LSB of the handler determines if we're going to
423 * be using THUMB or ARM mode for this signal handler.
429 #if __LINUX_ARM_ARCH__ >= 7
430 /* clear the If-Then Thumb-2 execution state */
431 cpsr &= ~PSR_IT_MASK;
438 if (ka->sa.sa_flags & SA_RESTORER) {
439 retcode = (unsigned long)ka->sa.sa_restorer;
441 unsigned int idx = thumb << 1;
443 if (ka->sa.sa_flags & SA_SIGINFO)
446 if (__put_user(sigreturn_codes[idx], rc) ||
447 __put_user(sigreturn_codes[idx+1], rc+1))
450 if (cpsr & MODE32_BIT) {
452 * 32-bit code can use the new high-page
453 * signal return code support.
455 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
458 * Ensure that the instruction cache sees
459 * the return code written onto the stack.
461 flush_icache_range((unsigned long)rc,
462 (unsigned long)(rc + 2));
464 retcode = ((unsigned long)rc) + thumb;
469 regs->ARM_sp = (unsigned long)frame;
470 regs->ARM_lr = retcode;
471 regs->ARM_pc = handler;
472 regs->ARM_cpsr = cpsr;
478 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
480 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
487 * Set uc.uc_flags to a value which sc.trap_no would never have.
489 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
491 err |= setup_sigframe(frame, regs, set);
493 err = setup_return(regs, ka, frame->retcode, frame, usig);
499 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
500 sigset_t *set, struct pt_regs *regs)
502 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
509 err |= copy_siginfo_to_user(&frame->info, info);
511 __put_user_error(0, &frame->sig.uc.uc_flags, err);
512 __put_user_error(NULL, &frame->sig.uc.uc_link, err);
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));
520 err |= setup_sigframe(&frame->sig, regs, set);
522 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
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
530 regs->ARM_r1 = (unsigned long)&frame->info;
531 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
538 * OK, we're invoking a handler
541 handle_signal(unsigned long sig, struct k_sigaction *ka,
542 siginfo_t *info, struct pt_regs *regs)
544 struct thread_info *thread = current_thread_info();
545 struct task_struct *tsk = current;
546 sigset_t *oldset = sigmask_to_save();
551 * translate the signal
553 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
554 usig = thread->exec_domain->signal_invmap[usig];
557 * Set up the stack frame
559 if (ka->sa.sa_flags & SA_SIGINFO)
560 ret = setup_rt_frame(usig, ka, info, oldset, regs);
562 ret = setup_frame(usig, ka, oldset, regs);
565 * Check that the resulting registers are actually sane.
567 ret |= !valid_user_regs(regs);
570 force_sigsegv(sig, tsk);
573 signal_delivered(sig, info, ka, regs, 0);
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
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.
585 static void do_signal(struct pt_regs *regs, int syscall)
587 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
588 struct k_sigaction ka;
593 * If we were from a system call, check for system call restarting...
596 continue_addr = regs->ARM_pc;
597 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
598 retval = regs->ARM_r0;
601 * Prepare for system call restart. We do this here so that a
602 * debugger will see the already changed PSW.
605 case -ERESTARTNOHAND:
607 case -ERESTARTNOINTR:
608 regs->ARM_r0 = regs->ARM_ORIG_r0;
609 regs->ARM_pc = restart_addr;
611 case -ERESTART_RESTARTBLOCK:
612 regs->ARM_r0 = -EINTR;
618 * Get the signal to deliver. When running under ptrace, at this
619 * point the debugger may change all our registers ...
621 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
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.
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;
637 handle_signal(signr, &ka, &info, regs);
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.
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;
653 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
654 regs->ARM_r7 = __NR_restart_syscall;
660 usp = (u32 __user *)regs->ARM_sp;
662 if (put_user(regs->ARM_pc, usp) == 0) {
663 regs->ARM_pc = KERN_RESTART_CODE;
666 force_sigsegv(0, current);
673 restore_saved_sigmask();
677 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
679 if (thread_flags & _TIF_SIGPENDING)
680 do_signal(regs, syscall);
682 if (thread_flags & _TIF_NOTIFY_RESUME) {
683 clear_thread_flag(TIF_NOTIFY_RESUME);
684 tracehook_notify_resume(regs);