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/random.h>
12 #include <linux/signal.h>
13 #include <linux/personality.h>
14 #include <linux/uaccess.h>
15 #include <linux/tracehook.h>
18 #include <asm/cacheflush.h>
19 #include <asm/traps.h>
20 #include <asm/ucontext.h>
21 #include <asm/unistd.h>
24 extern const unsigned long sigreturn_codes[7];
26 static unsigned long signal_return_offset;
29 static int preserve_crunch_context(struct crunch_sigframe __user *frame)
31 char kbuf[sizeof(*frame) + 8];
32 struct crunch_sigframe *kframe;
34 /* the crunch context must be 64 bit aligned */
35 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
36 kframe->magic = CRUNCH_MAGIC;
37 kframe->size = CRUNCH_STORAGE_SIZE;
38 crunch_task_copy(current_thread_info(), &kframe->storage);
39 return __copy_to_user(frame, kframe, sizeof(*frame));
42 static int restore_crunch_context(struct crunch_sigframe __user *frame)
44 char kbuf[sizeof(*frame) + 8];
45 struct crunch_sigframe *kframe;
47 /* the crunch context must be 64 bit aligned */
48 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
49 if (__copy_from_user(kframe, frame, sizeof(*frame)))
51 if (kframe->magic != CRUNCH_MAGIC ||
52 kframe->size != CRUNCH_STORAGE_SIZE)
54 crunch_task_restore(current_thread_info(), &kframe->storage);
61 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
63 char kbuf[sizeof(*frame) + 8];
64 struct iwmmxt_sigframe *kframe;
66 /* the iWMMXt context must be 64 bit aligned */
67 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
68 kframe->magic = IWMMXT_MAGIC;
69 kframe->size = IWMMXT_STORAGE_SIZE;
70 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
71 return __copy_to_user(frame, kframe, sizeof(*frame));
74 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
76 char kbuf[sizeof(*frame) + 8];
77 struct iwmmxt_sigframe *kframe;
79 /* the iWMMXt context must be 64 bit aligned */
80 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
81 if (__copy_from_user(kframe, frame, sizeof(*frame)))
83 if (kframe->magic != IWMMXT_MAGIC ||
84 kframe->size != IWMMXT_STORAGE_SIZE)
86 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
94 static int preserve_vfp_context(struct vfp_sigframe __user *frame)
96 const unsigned long magic = VFP_MAGIC;
97 const unsigned long size = VFP_STORAGE_SIZE;
100 __put_user_error(magic, &frame->magic, err);
101 __put_user_error(size, &frame->size, err);
106 return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
109 static int restore_vfp_context(struct vfp_sigframe __user *frame)
115 __get_user_error(magic, &frame->magic, err);
116 __get_user_error(size, &frame->size, err);
120 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
123 return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
129 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
133 unsigned long retcode[2];
141 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
143 struct aux_sigframe __user *aux;
147 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
149 set_current_blocked(&set);
151 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
152 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
153 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
154 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
155 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
156 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
157 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
158 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
159 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
160 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
161 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
162 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
163 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
164 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
165 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
166 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
167 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
169 err |= !valid_user_regs(regs);
171 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
174 err |= restore_crunch_context(&aux->crunch);
177 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
178 err |= restore_iwmmxt_context(&aux->iwmmxt);
182 err |= restore_vfp_context(&aux->vfp);
188 asmlinkage int sys_sigreturn(struct pt_regs *regs)
190 struct sigframe __user *frame;
192 /* Always make any pending restarted system calls return -EINTR */
193 current_thread_info()->restart_block.fn = do_no_restart_syscall;
196 * Since we stacked the signal on a 64-bit boundary,
197 * then 'sp' should be word aligned here. If it's
198 * not, then the user is trying to mess with us.
200 if (regs->ARM_sp & 7)
203 frame = (struct sigframe __user *)regs->ARM_sp;
205 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
208 if (restore_sigframe(regs, frame))
214 force_sig(SIGSEGV, current);
218 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
220 struct rt_sigframe __user *frame;
222 /* Always make any pending restarted system calls return -EINTR */
223 current_thread_info()->restart_block.fn = do_no_restart_syscall;
226 * Since we stacked the signal on a 64-bit boundary,
227 * then 'sp' should be word aligned here. If it's
228 * not, then the user is trying to mess with us.
230 if (regs->ARM_sp & 7)
233 frame = (struct rt_sigframe __user *)regs->ARM_sp;
235 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
238 if (restore_sigframe(regs, &frame->sig))
241 if (restore_altstack(&frame->sig.uc.uc_stack))
247 force_sig(SIGSEGV, current);
252 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
254 struct aux_sigframe __user *aux;
257 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
258 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
259 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
260 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
261 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
262 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
263 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
264 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
265 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
266 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
267 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
268 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
269 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
270 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
271 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
272 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
273 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
275 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
276 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
277 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
278 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
280 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
282 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
285 err |= preserve_crunch_context(&aux->crunch);
288 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
289 err |= preserve_iwmmxt_context(&aux->iwmmxt);
293 err |= preserve_vfp_context(&aux->vfp);
295 __put_user_error(0, &aux->end_magic, err);
300 static inline void __user *
301 get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
303 unsigned long sp = sigsp(regs->ARM_sp, ksig);
307 * ATPCS B01 mandates 8-byte alignment
309 frame = (void __user *)((sp - framesize) & ~7);
312 * Check that we can actually write to the signal frame.
314 if (!access_ok(VERIFY_WRITE, frame, framesize))
321 * translate the signal
323 static inline int map_sig(int sig)
325 struct thread_info *thread = current_thread_info();
326 if (sig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
327 sig = thread->exec_domain->signal_invmap[sig];
332 setup_return(struct pt_regs *regs, struct ksignal *ksig,
333 unsigned long __user *rc, void __user *frame)
335 unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
336 unsigned long retcode;
338 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
340 cpsr |= PSR_ENDSTATE;
343 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
345 if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
346 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
348 #ifdef CONFIG_ARM_THUMB
349 if (elf_hwcap & HWCAP_THUMB) {
351 * The LSB of the handler determines if we're going to
352 * be using THUMB or ARM mode for this signal handler.
356 #if __LINUX_ARM_ARCH__ >= 7
358 * Clear the If-Then Thumb-2 execution state
359 * ARM spec requires this to be all 000s in ARM mode
360 * Snapdragon S4/Krait misbehaves on a Thumb=>ARM
361 * signal transition without this.
363 cpsr &= ~PSR_IT_MASK;
373 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
374 retcode = (unsigned long)ksig->ka.sa.sa_restorer;
376 unsigned int idx = thumb << 1;
378 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
382 * Put the sigreturn code on the stack no matter which return
383 * mechanism we use in order to remain ABI compliant
385 if (__put_user(sigreturn_codes[idx], rc) ||
386 __put_user(sigreturn_codes[idx+1], rc+1))
390 if (cpsr & MODE32_BIT) {
391 struct mm_struct *mm = current->mm;
394 * 32-bit code can use the signal return page
395 * except when the MPU has protected the vectors
398 retcode = mm->context.sigpage + signal_return_offset +
404 * Ensure that the instruction cache sees
405 * the return code written onto the stack.
407 flush_icache_range((unsigned long)rc,
408 (unsigned long)(rc + 2));
410 retcode = ((unsigned long)rc) + thumb;
414 regs->ARM_r0 = map_sig(ksig->sig);
415 regs->ARM_sp = (unsigned long)frame;
416 regs->ARM_lr = retcode;
417 regs->ARM_pc = handler;
418 regs->ARM_cpsr = cpsr;
424 setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
426 struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
433 * Set uc.uc_flags to a value which sc.trap_no would never have.
435 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
437 err |= setup_sigframe(frame, regs, set);
439 err = setup_return(regs, ksig, frame->retcode, frame);
445 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
447 struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
453 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
455 __put_user_error(0, &frame->sig.uc.uc_flags, err);
456 __put_user_error(NULL, &frame->sig.uc.uc_link, err);
458 err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
459 err |= setup_sigframe(&frame->sig, regs, set);
461 err = setup_return(regs, ksig, frame->sig.retcode, frame);
465 * For realtime signals we must also set the second and third
466 * arguments for the signal handler.
467 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
469 regs->ARM_r1 = (unsigned long)&frame->info;
470 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
477 * OK, we're invoking a handler
479 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
481 sigset_t *oldset = sigmask_to_save();
485 * Set up the stack frame
487 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
488 ret = setup_rt_frame(ksig, oldset, regs);
490 ret = setup_frame(ksig, oldset, regs);
493 * Check that the resulting registers are actually sane.
495 ret |= !valid_user_regs(regs);
497 signal_setup_done(ret, ksig, 0);
501 * Note that 'init' is a special process: it doesn't get signals it doesn't
502 * want to handle. Thus you cannot kill init even with a SIGKILL even by
505 * Note that we go through the signals twice: once to check the signals that
506 * the kernel can handle, and then we build all the user-level signal handling
507 * stack-frames in one go after that.
509 static int do_signal(struct pt_regs *regs, int syscall)
511 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
516 * If we were from a system call, check for system call restarting...
519 continue_addr = regs->ARM_pc;
520 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
521 retval = regs->ARM_r0;
524 * Prepare for system call restart. We do this here so that a
525 * debugger will see the already changed PSW.
528 case -ERESTART_RESTARTBLOCK:
530 case -ERESTARTNOHAND:
532 case -ERESTARTNOINTR:
534 regs->ARM_r0 = regs->ARM_ORIG_r0;
535 regs->ARM_pc = restart_addr;
541 * Get the signal to deliver. When running under ptrace, at this
542 * point the debugger may change all our registers ...
545 * Depending on the signal settings we may need to revert the
546 * decision to restart the system call. But skip this if a
547 * debugger has chosen to restart at a different PC.
549 if (get_signal(&ksig)) {
551 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
552 if (retval == -ERESTARTNOHAND ||
553 retval == -ERESTART_RESTARTBLOCK
554 || (retval == -ERESTARTSYS
555 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
556 regs->ARM_r0 = -EINTR;
557 regs->ARM_pc = continue_addr;
560 handle_signal(&ksig, regs);
563 restore_saved_sigmask();
564 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
565 regs->ARM_pc = continue_addr;
573 do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
576 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
579 if (unlikely(!user_mode(regs)))
582 if (thread_flags & _TIF_SIGPENDING) {
583 int restart = do_signal(regs, syscall);
584 if (unlikely(restart)) {
586 * Restart without handlers.
587 * Deal with it without leaving
594 clear_thread_flag(TIF_NOTIFY_RESUME);
595 tracehook_notify_resume(regs);
599 thread_flags = current_thread_info()->flags;
600 } while (thread_flags & _TIF_WORK_MASK);
604 struct page *get_signal_page(void)
611 page = alloc_pages(GFP_KERNEL, 0);
616 addr = page_address(page);
618 /* Give the signal return code some randomness */
619 offset = 0x200 + (get_random_int() & 0x7fc);
620 signal_return_offset = offset;
623 * Copy signal return handlers into the vector page, and
624 * set sigreturn to be a pointer to these.
626 memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
628 ptr = (unsigned long)addr + offset;
629 flush_icache_range(ptr, ptr + sizeof(sigreturn_codes));