2 * Copyright (C) 1991, 1992 Linus Torvalds
4 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
5 * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
7 #include <linux/list.h>
9 #include <linux/personality.h>
10 #include <linux/binfmts.h>
11 #include <linux/suspend.h>
12 #include <linux/kernel.h>
13 #include <linux/ptrace.h>
14 #include <linux/signal.h>
15 #include <linux/stddef.h>
16 #include <linux/unistd.h>
17 #include <linux/errno.h>
18 #include <linux/sched.h>
19 #include <linux/wait.h>
20 #include <linux/elf.h>
21 #include <linux/smp.h>
24 #include <asm/processor.h>
25 #include <asm/ucontext.h>
26 #include <asm/uaccess.h>
29 #include <asm/syscalls.h>
33 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
35 #define __FIX_EFLAGS (X86_EFLAGS_AC | X86_EFLAGS_OF | \
36 X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
37 X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
41 # define FIX_EFLAGS (__FIX_EFLAGS | X86_EFLAGS_RF)
43 # define FIX_EFLAGS __FIX_EFLAGS
47 * Atomically swap in the new signal mask, and wait for a signal.
50 sys_sigsuspend(int history0, int history1, old_sigset_t mask)
53 spin_lock_irq(¤t->sighand->siglock);
54 current->saved_sigmask = current->blocked;
55 siginitset(¤t->blocked, mask);
57 spin_unlock_irq(¤t->sighand->siglock);
59 current->state = TASK_INTERRUPTIBLE;
61 set_restore_sigmask();
63 return -ERESTARTNOHAND;
67 sys_sigaction(int sig, const struct old_sigaction __user *act,
68 struct old_sigaction __user *oact)
70 struct k_sigaction new_ka, old_ka;
76 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
77 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
78 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
81 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
82 __get_user(mask, &act->sa_mask);
83 siginitset(&new_ka.sa.sa_mask, mask);
86 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
89 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
90 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
91 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
94 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
95 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
101 asmlinkage int sys_sigaltstack(unsigned long bx)
104 * This is needed to make gcc realize it doesn't own the
107 struct pt_regs *regs = (struct pt_regs *)&bx;
108 const stack_t __user *uss = (const stack_t __user *)bx;
109 stack_t __user *uoss = (stack_t __user *)regs->cx;
111 return do_sigaltstack(uss, uoss, regs->sp);
116 * Do a signal return; undo the signal stack.
119 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
122 unsigned int err = 0;
124 /* Always make any pending restarted system calls return -EINTR */
125 current_thread_info()->restart_block.fn = do_no_restart_syscall;
127 #define COPY(x) err |= __get_user(regs->x, &sc->x)
129 #define COPY_SEG(seg) \
130 { unsigned short tmp; \
131 err |= __get_user(tmp, &sc->seg); \
134 #define COPY_SEG_STRICT(seg) \
135 { unsigned short tmp; \
136 err |= __get_user(tmp, &sc->seg); \
139 #define GET_SEG(seg) \
140 { unsigned short tmp; \
141 err |= __get_user(tmp, &sc->seg); \
142 loadsegment(seg, tmp); }
148 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
149 COPY(dx); COPY(cx); COPY(ip);
154 unsigned int tmpflags;
156 err |= __get_user(tmpflags, &sc->flags);
157 regs->flags = (regs->flags & ~FIX_EFLAGS) |
158 (tmpflags & FIX_EFLAGS);
159 regs->orig_ax = -1; /* disable syscall checks */
165 err |= __get_user(buf, &sc->fpstate);
166 err |= restore_i387_xstate(buf);
169 err |= __get_user(*pax, &sc->ax);
173 asmlinkage unsigned long sys_sigreturn(unsigned long __unused)
175 struct sigframe __user *frame;
176 struct pt_regs *regs;
180 regs = (struct pt_regs *) &__unused;
181 frame = (struct sigframe __user *)(regs->sp - 8);
183 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
185 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
186 && __copy_from_user(&set.sig[1], &frame->extramask,
187 sizeof(frame->extramask))))
190 sigdelsetmask(&set, ~_BLOCKABLE);
191 spin_lock_irq(¤t->sighand->siglock);
192 current->blocked = set;
194 spin_unlock_irq(¤t->sighand->siglock);
196 if (restore_sigcontext(regs, &frame->sc, &ax))
201 if (show_unhandled_signals && printk_ratelimit()) {
202 printk("%s%s[%d] bad frame in sigreturn frame:"
203 "%p ip:%lx sp:%lx oeax:%lx",
204 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
205 current->comm, task_pid_nr(current), frame, regs->ip,
206 regs->sp, regs->orig_ax);
207 print_vma_addr(" in ", regs->ip);
208 printk(KERN_CONT "\n");
211 force_sig(SIGSEGV, current);
216 asmlinkage int sys_rt_sigreturn(unsigned long __unused)
218 struct pt_regs *regs = (struct pt_regs *)&__unused;
219 struct rt_sigframe __user *frame;
223 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
224 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
226 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
229 sigdelsetmask(&set, ~_BLOCKABLE);
230 spin_lock_irq(¤t->sighand->siglock);
231 current->blocked = set;
233 spin_unlock_irq(¤t->sighand->siglock);
235 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
238 if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
244 force_sig(SIGSEGV, current);
249 * Set up a signal frame.
252 setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
253 struct pt_regs *regs, unsigned long mask)
257 err |= __put_user(regs->fs, (unsigned int __user *)&sc->fs);
258 savesegment(gs, tmp);
259 err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
261 err |= __put_user(regs->es, (unsigned int __user *)&sc->es);
262 err |= __put_user(regs->ds, (unsigned int __user *)&sc->ds);
263 err |= __put_user(regs->di, &sc->di);
264 err |= __put_user(regs->si, &sc->si);
265 err |= __put_user(regs->bp, &sc->bp);
266 err |= __put_user(regs->sp, &sc->sp);
267 err |= __put_user(regs->bx, &sc->bx);
268 err |= __put_user(regs->dx, &sc->dx);
269 err |= __put_user(regs->cx, &sc->cx);
270 err |= __put_user(regs->ax, &sc->ax);
271 err |= __put_user(current->thread.trap_no, &sc->trapno);
272 err |= __put_user(current->thread.error_code, &sc->err);
273 err |= __put_user(regs->ip, &sc->ip);
274 err |= __put_user(regs->cs, (unsigned int __user *)&sc->cs);
275 err |= __put_user(regs->flags, &sc->flags);
276 err |= __put_user(regs->sp, &sc->sp_at_signal);
277 err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
279 tmp = save_i387_xstate(fpstate);
283 err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
285 /* non-iBCS2 extensions.. */
286 err |= __put_user(mask, &sc->oldmask);
287 err |= __put_user(current->thread.cr2, &sc->cr2);
293 * Determine which stack to use..
295 static inline void __user *
296 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
301 /* Default to using normal stack */
305 * If we are on the alternate signal stack and would overflow it, don't.
306 * Return an always-bogus address instead so we will die with SIGSEGV.
308 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
309 return (void __user *) -1L;
311 /* This is the X/Open sanctioned signal stack switching. */
312 if (ka->sa.sa_flags & SA_ONSTACK) {
313 if (sas_ss_flags(sp) == 0)
314 sp = current->sas_ss_sp + current->sas_ss_size;
316 /* This is the legacy signal stack switching. */
317 if ((regs->ss & 0xffff) != __USER_DS &&
318 !(ka->sa.sa_flags & SA_RESTORER) &&
320 sp = (unsigned long) ka->sa.sa_restorer;
324 sp = sp - sig_xstate_size;
325 *fpstate = (struct _fpstate *) sp;
330 * Align the stack pointer according to the i386 ABI,
331 * i.e. so that on function entry ((sp + 4) & 15) == 0.
333 sp = ((sp + 4) & -16ul) - 4;
335 return (void __user *) sp;
339 setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
340 struct pt_regs *regs)
342 struct sigframe __user *frame;
343 void __user *restorer;
346 void __user *fpstate = NULL;
348 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
350 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
353 usig = current_thread_info()->exec_domain
354 && current_thread_info()->exec_domain->signal_invmap
356 ? current_thread_info()->exec_domain->signal_invmap[sig]
359 err = __put_user(usig, &frame->sig);
363 err = setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]);
367 if (_NSIG_WORDS > 1) {
368 err = __copy_to_user(&frame->extramask, &set->sig[1],
369 sizeof(frame->extramask));
374 if (current->mm->context.vdso)
375 restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
377 restorer = &frame->retcode;
378 if (ka->sa.sa_flags & SA_RESTORER)
379 restorer = ka->sa.sa_restorer;
381 /* Set up to return from userspace. */
382 err |= __put_user(restorer, &frame->pretcode);
385 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
387 * WE DO NOT USE IT ANY MORE! It's only left here for historical
388 * reasons and because gdb uses it as a signature to notice
389 * signal handler stack frames.
391 err |= __put_user(0xb858, (short __user *)(frame->retcode+0));
392 err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
393 err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
398 /* Set up registers for signal handler */
399 regs->sp = (unsigned long)frame;
400 regs->ip = (unsigned long)ka->sa.sa_handler;
401 regs->ax = (unsigned long)sig;
405 regs->ds = __USER_DS;
406 regs->es = __USER_DS;
407 regs->ss = __USER_DS;
408 regs->cs = __USER_CS;
413 force_sigsegv(sig, current);
417 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
418 sigset_t *set, struct pt_regs *regs)
420 struct rt_sigframe __user *frame;
421 void __user *restorer;
424 void __user *fpstate = NULL;
426 frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
428 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
431 usig = current_thread_info()->exec_domain
432 && current_thread_info()->exec_domain->signal_invmap
434 ? current_thread_info()->exec_domain->signal_invmap[sig]
437 err |= __put_user(usig, &frame->sig);
438 err |= __put_user(&frame->info, &frame->pinfo);
439 err |= __put_user(&frame->uc, &frame->puc);
440 err |= copy_siginfo_to_user(&frame->info, info);
444 /* Create the ucontext. */
446 err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
448 err |= __put_user(0, &frame->uc.uc_flags);
449 err |= __put_user(0, &frame->uc.uc_link);
450 err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
451 err |= __put_user(sas_ss_flags(regs->sp),
452 &frame->uc.uc_stack.ss_flags);
453 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
454 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
456 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
460 /* Set up to return from userspace. */
461 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
462 if (ka->sa.sa_flags & SA_RESTORER)
463 restorer = ka->sa.sa_restorer;
464 err |= __put_user(restorer, &frame->pretcode);
467 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
469 * WE DO NOT USE IT ANY MORE! It's only left here for historical
470 * reasons and because gdb uses it as a signature to notice
471 * signal handler stack frames.
473 err |= __put_user(0xb8, (char __user *)(frame->retcode+0));
474 err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
475 err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
480 /* Set up registers for signal handler */
481 regs->sp = (unsigned long)frame;
482 regs->ip = (unsigned long)ka->sa.sa_handler;
483 regs->ax = (unsigned long)usig;
484 regs->dx = (unsigned long)&frame->info;
485 regs->cx = (unsigned long)&frame->uc;
487 regs->ds = __USER_DS;
488 regs->es = __USER_DS;
489 regs->ss = __USER_DS;
490 regs->cs = __USER_CS;
495 force_sigsegv(sig, current);
500 * OK, we're invoking a handler:
503 handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
504 sigset_t *oldset, struct pt_regs *regs)
508 /* Are we from a system call? */
509 if ((long)regs->orig_ax >= 0) {
510 /* If so, check system call restarting.. */
512 case -ERESTART_RESTARTBLOCK:
513 case -ERESTARTNOHAND:
518 if (!(ka->sa.sa_flags & SA_RESTART)) {
523 case -ERESTARTNOINTR:
524 regs->ax = regs->orig_ax;
531 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
532 * flag so that register information in the sigcontext is correct.
534 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
535 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
536 regs->flags &= ~X86_EFLAGS_TF;
538 /* Set up the stack frame */
539 if (ka->sa.sa_flags & SA_SIGINFO)
540 ret = setup_rt_frame(sig, ka, info, oldset, regs);
542 ret = setup_frame(sig, ka, oldset, regs);
548 * Clear the direction flag as per the ABI for function entry.
550 regs->flags &= ~X86_EFLAGS_DF;
553 * Clear TF when entering the signal handler, but
554 * notify any tracer that was single-stepping it.
555 * The tracer may want to single-step inside the
558 regs->flags &= ~X86_EFLAGS_TF;
559 if (test_thread_flag(TIF_SINGLESTEP))
560 ptrace_notify(SIGTRAP);
562 spin_lock_irq(¤t->sighand->siglock);
563 sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask);
564 if (!(ka->sa.sa_flags & SA_NODEFER))
565 sigaddset(¤t->blocked, sig);
567 spin_unlock_irq(¤t->sighand->siglock);
573 * Note that 'init' is a special process: it doesn't get signals it doesn't
574 * want to handle. Thus you cannot kill init even with a SIGKILL even by
577 static void do_signal(struct pt_regs *regs)
579 struct k_sigaction ka;
585 * We want the common case to go fast, which is why we may in certain
586 * cases get here from kernel mode. Just return without doing anything
588 * X86_32: vm86 regs switched out by assembly code before reaching
589 * here, so testing against kernel CS suffices.
591 if (!user_mode(regs))
594 if (current_thread_info()->status & TS_RESTORE_SIGMASK)
595 oldset = ¤t->saved_sigmask;
597 oldset = ¤t->blocked;
599 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
602 * Re-enable any watchpoints before delivering the
603 * signal to user space. The processor register will
604 * have been cleared if the watchpoint triggered
607 if (current->thread.debugreg7)
608 set_debugreg(current->thread.debugreg7, 7);
610 /* Whee! Actually deliver the signal. */
611 if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
613 * A signal was successfully delivered; the saved
614 * sigmask will have been stored in the signal frame,
615 * and will be restored by sigreturn, so we can simply
616 * clear the TS_RESTORE_SIGMASK flag.
618 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
623 /* Did we come from a system call? */
624 if ((long)regs->orig_ax >= 0) {
625 /* Restart the system call - no handlers present */
627 case -ERESTARTNOHAND:
629 case -ERESTARTNOINTR:
630 regs->ax = regs->orig_ax;
634 case -ERESTART_RESTARTBLOCK:
635 regs->ax = __NR_restart_syscall;
642 * If there's no signal to deliver, we just put the saved sigmask
645 if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
646 current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
647 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
652 * notification of userspace execution resumption
653 * - triggered by the TIF_WORK_MASK flags
656 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
658 /* deal with pending signal delivery */
659 if (thread_info_flags & _TIF_SIGPENDING)
662 clear_thread_flag(TIF_IRET);