2 * linux/arch/i386/kernel/signal.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
7 * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
10 #include <linux/sched.h>
12 #include <linux/smp.h>
13 #include <linux/smp_lock.h>
14 #include <linux/kernel.h>
15 #include <linux/signal.h>
16 #include <linux/errno.h>
17 #include <linux/wait.h>
18 #include <linux/unistd.h>
19 #include <linux/stddef.h>
20 #include <linux/personality.h>
21 #include <linux/suspend.h>
22 #include <linux/tracehook.h>
23 #include <linux/elf.h>
24 #include <linux/binfmts.h>
25 #include <asm/processor.h>
26 #include <asm/ucontext.h>
27 #include <asm/uaccess.h>
33 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
36 * Atomically swap in the new signal mask, and wait for a signal.
39 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
42 spin_lock_irq(¤t->sighand->siglock);
43 current->saved_sigmask = current->blocked;
44 siginitset(¤t->blocked, mask);
46 spin_unlock_irq(¤t->sighand->siglock);
48 current->state = TASK_INTERRUPTIBLE;
50 set_thread_flag(TIF_RESTORE_SIGMASK);
51 return -ERESTARTNOHAND;
55 sys_sigaction(int sig, const struct old_sigaction __user *act,
56 struct old_sigaction __user *oact)
58 struct k_sigaction new_ka, old_ka;
63 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
64 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
65 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
67 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
68 __get_user(mask, &act->sa_mask);
69 siginitset(&new_ka.sa.sa_mask, mask);
72 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
75 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
76 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
77 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
79 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
80 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
87 sys_sigaltstack(unsigned long ebx)
89 /* This is needed to make gcc realize it doesn't own the "struct pt_regs" */
90 struct pt_regs *regs = (struct pt_regs *)&ebx;
91 const stack_t __user *uss = (const stack_t __user *)ebx;
92 stack_t __user *uoss = (stack_t __user *)regs->ecx;
94 return do_sigaltstack(uss, uoss, regs->esp);
99 * Do a signal return; undo the signal stack.
103 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *peax)
105 unsigned int err = 0;
107 /* Always make any pending restarted system calls return -EINTR */
108 current_thread_info()->restart_block.fn = do_no_restart_syscall;
110 #define COPY(x) err |= __get_user(regs->x, &sc->x)
112 #define COPY_SEG(seg) \
113 { unsigned short tmp; \
114 err |= __get_user(tmp, &sc->seg); \
115 regs->x##seg = tmp; }
117 #define COPY_SEG_STRICT(seg) \
118 { unsigned short tmp; \
119 err |= __get_user(tmp, &sc->seg); \
120 regs->x##seg = tmp|3; }
122 #define GET_SEG(seg) \
123 { unsigned short tmp; \
124 err |= __get_user(tmp, &sc->seg); \
125 loadsegment(seg,tmp); }
127 #define FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_RF | \
128 X86_EFLAGS_OF | X86_EFLAGS_DF | \
129 X86_EFLAGS_TF | X86_EFLAGS_SF | X86_EFLAGS_ZF | \
130 X86_EFLAGS_AF | X86_EFLAGS_PF | X86_EFLAGS_CF)
148 unsigned int tmpflags;
149 err |= __get_user(tmpflags, &sc->eflags);
150 regs->eflags = (regs->eflags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
151 regs->orig_eax = -1; /* disable syscall checks */
155 struct _fpstate __user * buf;
156 err |= __get_user(buf, &sc->fpstate);
158 if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
160 err |= restore_i387(buf);
162 struct task_struct *me = current;
170 err |= __get_user(*peax, &sc->eax);
177 asmlinkage int sys_sigreturn(unsigned long __unused)
179 struct pt_regs *regs = (struct pt_regs *) &__unused;
180 struct sigframe __user *frame = (struct sigframe __user *)(regs->esp - 8);
184 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
186 if (__get_user(set.sig[0], &frame->sc.oldmask)
188 && __copy_from_user(&set.sig[1], &frame->extramask,
189 sizeof(frame->extramask))))
192 sigdelsetmask(&set, ~_BLOCKABLE);
193 spin_lock_irq(¤t->sighand->siglock);
194 current->blocked = set;
196 spin_unlock_irq(¤t->sighand->siglock);
198 if (restore_sigcontext(regs, &frame->sc, &eax))
203 force_sig(SIGSEGV, current);
207 asmlinkage int sys_rt_sigreturn(unsigned long __unused)
209 struct pt_regs *regs = (struct pt_regs *) &__unused;
210 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(regs->esp - 4);
214 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
216 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
219 sigdelsetmask(&set, ~_BLOCKABLE);
220 spin_lock_irq(¤t->sighand->siglock);
221 current->blocked = set;
223 spin_unlock_irq(¤t->sighand->siglock);
225 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax))
228 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->esp) == -EFAULT)
234 force_sig(SIGSEGV, current);
239 * Set up a signal frame.
243 setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate,
244 struct pt_regs *regs, unsigned long mask)
248 err |= __put_user(regs->xgs, (unsigned int __user *)&sc->gs);
249 savesegment(fs, tmp);
250 err |= __put_user(tmp, (unsigned int __user *)&sc->fs);
252 err |= __put_user(regs->xes, (unsigned int __user *)&sc->es);
253 err |= __put_user(regs->xds, (unsigned int __user *)&sc->ds);
254 err |= __put_user(regs->edi, &sc->edi);
255 err |= __put_user(regs->esi, &sc->esi);
256 err |= __put_user(regs->ebp, &sc->ebp);
257 err |= __put_user(regs->esp, &sc->esp);
258 err |= __put_user(regs->ebx, &sc->ebx);
259 err |= __put_user(regs->edx, &sc->edx);
260 err |= __put_user(regs->ecx, &sc->ecx);
261 err |= __put_user(regs->eax, &sc->eax);
262 err |= __put_user(current->thread.trap_no, &sc->trapno);
263 err |= __put_user(current->thread.error_code, &sc->err);
264 err |= __put_user(regs->eip, &sc->eip);
265 err |= __put_user(regs->xcs, (unsigned int __user *)&sc->cs);
266 err |= __put_user(regs->eflags, &sc->eflags);
267 err |= __put_user(regs->esp, &sc->esp_at_signal);
268 err |= __put_user(regs->xss, (unsigned int __user *)&sc->ss);
270 tmp = save_i387(fpstate);
274 err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
276 /* non-iBCS2 extensions.. */
277 err |= __put_user(mask, &sc->oldmask);
278 err |= __put_user(current->thread.cr2, &sc->cr2);
284 * Determine which stack to use..
286 static inline void __user *
287 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
291 /* Default to using normal stack */
294 /* This is the X/Open sanctioned signal stack switching. */
295 if (ka->sa.sa_flags & SA_ONSTACK) {
296 if (sas_ss_flags(esp) == 0)
297 esp = current->sas_ss_sp + current->sas_ss_size;
300 /* This is the legacy signal stack switching. */
301 else if ((regs->xss & 0xffff) != __USER_DS &&
302 !(ka->sa.sa_flags & SA_RESTORER) &&
303 ka->sa.sa_restorer) {
304 esp = (unsigned long) ka->sa.sa_restorer;
308 /* Align the stack pointer according to the i386 ABI,
309 * i.e. so that on function entry ((sp + 4) & 15) == 0. */
310 esp = ((esp + 4) & -16ul) - 4;
311 return (void __user *) esp;
314 /* These symbols are defined with the addresses in the vsyscall page.
315 See vsyscall-sigreturn.S. */
316 extern void __user __kernel_sigreturn;
317 extern void __user __kernel_rt_sigreturn;
319 static int setup_frame(int sig, struct k_sigaction *ka,
320 sigset_t *set, struct pt_regs * regs)
322 void __user *restorer;
323 struct sigframe __user *frame;
327 frame = get_sigframe(ka, regs, sizeof(*frame));
329 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
332 usig = current_thread_info()->exec_domain
333 && current_thread_info()->exec_domain->signal_invmap
335 ? current_thread_info()->exec_domain->signal_invmap[sig]
338 err = __put_user(usig, &frame->sig);
342 err = setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
346 if (_NSIG_WORDS > 1) {
347 err = __copy_to_user(&frame->extramask, &set->sig[1],
348 sizeof(frame->extramask));
353 if (current->binfmt->hasvdso)
354 restorer = (void *)VDSO_SYM(&__kernel_sigreturn);
356 restorer = (void *)&frame->retcode;
357 if (ka->sa.sa_flags & SA_RESTORER)
358 restorer = ka->sa.sa_restorer;
360 /* Set up to return from userspace. */
361 err |= __put_user(restorer, &frame->pretcode);
364 * This is popl %eax ; movl $,%eax ; int $0x80
366 * WE DO NOT USE IT ANY MORE! It's only left here for historical
367 * reasons and because gdb uses it as a signature to notice
368 * signal handler stack frames.
370 err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
371 err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
372 err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
377 /* Set up registers for signal handler */
378 regs->esp = (unsigned long) frame;
379 regs->eip = (unsigned long) ka->sa.sa_handler;
380 regs->eax = (unsigned long) sig;
381 regs->edx = (unsigned long) 0;
382 regs->ecx = (unsigned long) 0;
385 regs->xds = __USER_DS;
386 regs->xes = __USER_DS;
387 regs->xss = __USER_DS;
388 regs->xcs = __USER_CS;
391 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
392 current->comm, current->pid, frame, regs->eip, frame->pretcode);
398 force_sigsegv(sig, current);
402 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
403 sigset_t *set, struct pt_regs * regs)
405 void __user *restorer;
406 struct rt_sigframe __user *frame;
410 frame = get_sigframe(ka, regs, sizeof(*frame));
412 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
415 usig = current_thread_info()->exec_domain
416 && current_thread_info()->exec_domain->signal_invmap
418 ? current_thread_info()->exec_domain->signal_invmap[sig]
421 err |= __put_user(usig, &frame->sig);
422 err |= __put_user(&frame->info, &frame->pinfo);
423 err |= __put_user(&frame->uc, &frame->puc);
424 err |= copy_siginfo_to_user(&frame->info, info);
428 /* Create the ucontext. */
429 err |= __put_user(0, &frame->uc.uc_flags);
430 err |= __put_user(0, &frame->uc.uc_link);
431 err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
432 err |= __put_user(sas_ss_flags(regs->esp),
433 &frame->uc.uc_stack.ss_flags);
434 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
435 err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate,
437 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
441 /* Set up to return from userspace. */
442 restorer = (void *)VDSO_SYM(&__kernel_rt_sigreturn);
443 if (ka->sa.sa_flags & SA_RESTORER)
444 restorer = ka->sa.sa_restorer;
445 err |= __put_user(restorer, &frame->pretcode);
448 * This is movl $,%eax ; int $0x80
450 * WE DO NOT USE IT ANY MORE! It's only left here for historical
451 * reasons and because gdb uses it as a signature to notice
452 * signal handler stack frames.
454 err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
455 err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
456 err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
461 /* Set up registers for signal handler */
462 regs->esp = (unsigned long) frame;
463 regs->eip = (unsigned long) ka->sa.sa_handler;
464 regs->eax = (unsigned long) usig;
465 regs->edx = (unsigned long) &frame->info;
466 regs->ecx = (unsigned long) &frame->uc;
469 regs->xds = __USER_DS;
470 regs->xes = __USER_DS;
471 regs->xss = __USER_DS;
472 regs->xcs = __USER_CS;
475 printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
476 current->comm, current->pid, frame, regs->eip, frame->pretcode);
482 force_sigsegv(sig, current);
487 * OK, we're invoking a handler
491 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
492 sigset_t *oldset, struct pt_regs * regs)
496 /* Are we from a system call? */
497 if (regs->orig_eax >= 0) {
498 /* If so, check system call restarting.. */
500 case -ERESTART_RESTARTBLOCK:
501 case -ERESTARTNOHAND:
506 if (!(ka->sa.sa_flags & SA_RESTART)) {
511 case -ERESTARTNOINTR:
512 regs->eax = regs->orig_eax;
518 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF flag so
519 * that register information in the sigcontext is correct.
521 if (unlikely(regs->eflags & TF_MASK)
522 && likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
523 regs->eflags &= ~TF_MASK;
525 /* Set up the stack frame */
526 if (ka->sa.sa_flags & SA_SIGINFO)
527 ret = setup_rt_frame(sig, ka, info, oldset, regs);
529 ret = setup_frame(sig, ka, oldset, regs);
532 spin_lock_irq(¤t->sighand->siglock);
533 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
534 if (!(ka->sa.sa_flags & SA_NODEFER))
535 sigaddset(¤t->blocked,sig);
537 spin_unlock_irq(¤t->sighand->siglock);
540 * Clear TF when entering the signal handler, but
541 * notify any tracer that was single-stepping it.
542 * The tracer may want to single-step inside the
545 regs->eflags &= ~TF_MASK;
546 tracehook_report_handle_signal(sig, ka, oldset, regs);
553 * Note that 'init' is a special process: it doesn't get signals it doesn't
554 * want to handle. Thus you cannot kill init even with a SIGKILL even by
557 static void fastcall do_signal(struct pt_regs *regs)
561 struct k_sigaction ka;
565 * We want the common case to go fast, which
566 * is why we may in certain cases get here from
567 * kernel mode. Just return without doing anything
568 * if so. vm86 regs switched out by assembly code
569 * before reaching here, so testing against kernel
572 if (!user_mode(regs))
575 if (test_thread_flag(TIF_RESTORE_SIGMASK))
576 oldset = ¤t->saved_sigmask;
578 oldset = ¤t->blocked;
580 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
582 /* Reenable any watchpoints before delivering the
583 * signal to user space. The processor register will
584 * have been cleared if the watchpoint triggered
587 if (unlikely(current->thread.debugreg[7]))
588 set_debugreg(current->thread.debugreg[7], 7);
590 /* Whee! Actually deliver the signal. */
591 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
592 /* a signal was successfully delivered; the saved
593 * sigmask will have been stored in the signal frame,
594 * and will be restored by sigreturn, so we can simply
595 * clear the TIF_RESTORE_SIGMASK flag */
596 if (test_thread_flag(TIF_RESTORE_SIGMASK))
597 clear_thread_flag(TIF_RESTORE_SIGMASK);
603 /* Did we come from a system call? */
604 if (regs->orig_eax >= 0) {
605 /* Restart the system call - no handlers present */
607 case -ERESTARTNOHAND:
609 case -ERESTARTNOINTR:
610 regs->eax = regs->orig_eax;
614 case -ERESTART_RESTARTBLOCK:
615 regs->eax = __NR_restart_syscall;
621 /* if there's no signal to deliver, we just put the saved sigmask
623 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
624 clear_thread_flag(TIF_RESTORE_SIGMASK);
625 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
630 * notification of userspace execution resumption
631 * - triggered by the TIF_WORK_MASK flags
633 __attribute__((regparm(3)))
634 void do_notify_resume(struct pt_regs *regs, void *_unused,
635 __u32 thread_info_flags)
637 /* Pending single-step? */
638 if (thread_info_flags & _TIF_SINGLESTEP) {
639 regs->eflags |= TF_MASK;
640 clear_thread_flag(TIF_SINGLESTEP);
643 /* deal with pending signal delivery */
644 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
647 clear_thread_flag(TIF_IRET);