2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
5 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
6 * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
7 * 2000-2002 x86-64 support by Andi Kleen
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 #include <linux/sched.h>
14 #include <linux/smp.h>
15 #include <linux/kernel.h>
16 #include <linux/errno.h>
17 #include <linux/wait.h>
18 #include <linux/tracehook.h>
19 #include <linux/unistd.h>
20 #include <linux/stddef.h>
21 #include <linux/personality.h>
22 #include <linux/uaccess.h>
23 #include <linux/user-return-notifier.h>
24 #include <linux/uprobes.h>
25 #include <linux/context_tracking.h>
27 #include <asm/processor.h>
28 #include <asm/ucontext.h>
30 #include <asm/fpu-internal.h>
33 #include <asm/sighandling.h>
36 #include <asm/proto.h>
37 #include <asm/ia32_unistd.h>
38 #include <asm/sys_ia32.h>
39 #endif /* CONFIG_X86_64 */
41 #include <asm/syscall.h>
42 #include <asm/syscalls.h>
44 #include <asm/sigframe.h>
46 #define COPY(x) do { \
47 get_user_ex(regs->x, &sc->x); \
50 #define GET_SEG(seg) ({ \
52 get_user_ex(tmp, &sc->seg); \
56 #define COPY_SEG(seg) do { \
57 regs->seg = GET_SEG(seg); \
60 #define COPY_SEG_CPL3(seg) do { \
61 regs->seg = GET_SEG(seg) | 3; \
64 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
67 unsigned int tmpflags;
70 /* Always make any pending restarted system calls return -EINTR */
71 current->restart_block.fn = do_no_restart_syscall;
76 set_user_gs(regs, GET_SEG(gs));
80 #endif /* CONFIG_X86_32 */
82 COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
83 COPY(dx); COPY(cx); COPY(ip); COPY(ax);
94 #endif /* CONFIG_X86_64 */
99 get_user_ex(tmpflags, &sc->flags);
100 regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
101 regs->orig_ax = -1; /* disable syscall checks */
103 get_user_ex(buf, &sc->fpstate);
104 } get_user_catch(err);
106 err |= restore_xstate_sig(buf, config_enabled(CONFIG_X86_32));
113 int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
114 struct pt_regs *regs, unsigned long mask)
121 put_user_ex(get_user_gs(regs), (unsigned int __user *)&sc->gs);
122 put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
123 put_user_ex(regs->es, (unsigned int __user *)&sc->es);
124 put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
125 #endif /* CONFIG_X86_32 */
127 put_user_ex(regs->di, &sc->di);
128 put_user_ex(regs->si, &sc->si);
129 put_user_ex(regs->bp, &sc->bp);
130 put_user_ex(regs->sp, &sc->sp);
131 put_user_ex(regs->bx, &sc->bx);
132 put_user_ex(regs->dx, &sc->dx);
133 put_user_ex(regs->cx, &sc->cx);
134 put_user_ex(regs->ax, &sc->ax);
136 put_user_ex(regs->r8, &sc->r8);
137 put_user_ex(regs->r9, &sc->r9);
138 put_user_ex(regs->r10, &sc->r10);
139 put_user_ex(regs->r11, &sc->r11);
140 put_user_ex(regs->r12, &sc->r12);
141 put_user_ex(regs->r13, &sc->r13);
142 put_user_ex(regs->r14, &sc->r14);
143 put_user_ex(regs->r15, &sc->r15);
144 #endif /* CONFIG_X86_64 */
146 put_user_ex(current->thread.trap_nr, &sc->trapno);
147 put_user_ex(current->thread.error_code, &sc->err);
148 put_user_ex(regs->ip, &sc->ip);
150 put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
151 put_user_ex(regs->flags, &sc->flags);
152 put_user_ex(regs->sp, &sc->sp_at_signal);
153 put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
154 #else /* !CONFIG_X86_32 */
155 put_user_ex(regs->flags, &sc->flags);
156 put_user_ex(regs->cs, &sc->cs);
157 put_user_ex(0, &sc->__pad2);
158 put_user_ex(0, &sc->__pad1);
159 put_user_ex(regs->ss, &sc->ss);
160 #endif /* CONFIG_X86_32 */
162 put_user_ex(fpstate, &sc->fpstate);
164 /* non-iBCS2 extensions.. */
165 put_user_ex(mask, &sc->oldmask);
166 put_user_ex(current->thread.cr2, &sc->cr2);
167 } put_user_catch(err);
173 * Set up a signal frame.
177 * Determine which stack to use..
179 static unsigned long align_sigframe(unsigned long sp)
183 * Align the stack pointer according to the i386 ABI,
184 * i.e. so that on function entry ((sp + 4) & 15) == 0.
186 sp = ((sp + 4) & -16ul) - 4;
187 #else /* !CONFIG_X86_32 */
188 sp = round_down(sp, 16) - 8;
193 static inline void __user *
194 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
195 void __user **fpstate)
197 /* Default to using normal stack */
198 unsigned long math_size = 0;
199 unsigned long sp = regs->sp;
200 unsigned long buf_fx = 0;
201 int onsigstack = on_sig_stack(sp);
204 if (config_enabled(CONFIG_X86_64))
208 /* This is the X/Open sanctioned signal stack switching. */
209 if (ka->sa.sa_flags & SA_ONSTACK) {
210 if (current->sas_ss_size)
211 sp = current->sas_ss_sp + current->sas_ss_size;
212 } else if (config_enabled(CONFIG_X86_32) &&
213 (regs->ss & 0xffff) != __USER_DS &&
214 !(ka->sa.sa_flags & SA_RESTORER) &&
215 ka->sa.sa_restorer) {
216 /* This is the legacy signal stack switching. */
217 sp = (unsigned long) ka->sa.sa_restorer;
222 sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
223 &buf_fx, &math_size);
224 *fpstate = (void __user *)sp;
227 sp = align_sigframe(sp - frame_size);
230 * If we are on the alternate signal stack and would overflow it, don't.
231 * Return an always-bogus address instead so we will die with SIGSEGV.
233 if (onsigstack && !likely(on_sig_stack(sp)))
234 return (void __user *)-1L;
236 /* save i387 and extended state */
238 save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
239 return (void __user *)-1L;
241 return (void __user *)sp;
245 static const struct {
249 } __attribute__((packed)) retcode = {
250 0xb858, /* popl %eax; movl $..., %eax */
252 0x80cd, /* int $0x80 */
255 static const struct {
260 } __attribute__((packed)) rt_retcode = {
261 0xb8, /* movl $..., %eax */
263 0x80cd, /* int $0x80 */
268 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
269 struct pt_regs *regs)
271 struct sigframe __user *frame;
272 void __user *restorer;
274 void __user *fpstate = NULL;
276 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
278 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
281 if (__put_user(sig, &frame->sig))
284 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
287 if (_NSIG_WORDS > 1) {
288 if (__copy_to_user(&frame->extramask, &set->sig[1],
289 sizeof(frame->extramask)))
293 if (current->mm->context.vdso)
294 restorer = current->mm->context.vdso +
295 selected_vdso32->sym___kernel_sigreturn;
297 restorer = &frame->retcode;
298 if (ksig->ka.sa.sa_flags & SA_RESTORER)
299 restorer = ksig->ka.sa.sa_restorer;
301 /* Set up to return from userspace. */
302 err |= __put_user(restorer, &frame->pretcode);
305 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
307 * WE DO NOT USE IT ANY MORE! It's only left here for historical
308 * reasons and because gdb uses it as a signature to notice
309 * signal handler stack frames.
311 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
316 /* Set up registers for signal handler */
317 regs->sp = (unsigned long)frame;
318 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
319 regs->ax = (unsigned long)sig;
323 regs->ds = __USER_DS;
324 regs->es = __USER_DS;
325 regs->ss = __USER_DS;
326 regs->cs = __USER_CS;
331 static int __setup_rt_frame(int sig, struct ksignal *ksig,
332 sigset_t *set, struct pt_regs *regs)
334 struct rt_sigframe __user *frame;
335 void __user *restorer;
337 void __user *fpstate = NULL;
339 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
341 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
345 put_user_ex(sig, &frame->sig);
346 put_user_ex(&frame->info, &frame->pinfo);
347 put_user_ex(&frame->uc, &frame->puc);
349 /* Create the ucontext. */
351 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
353 put_user_ex(0, &frame->uc.uc_flags);
354 put_user_ex(0, &frame->uc.uc_link);
355 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
357 /* Set up to return from userspace. */
358 restorer = current->mm->context.vdso +
359 selected_vdso32->sym___kernel_rt_sigreturn;
360 if (ksig->ka.sa.sa_flags & SA_RESTORER)
361 restorer = ksig->ka.sa.sa_restorer;
362 put_user_ex(restorer, &frame->pretcode);
365 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
367 * WE DO NOT USE IT ANY MORE! It's only left here for historical
368 * reasons and because gdb uses it as a signature to notice
369 * signal handler stack frames.
371 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
372 } put_user_catch(err);
374 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
375 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
377 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
382 /* Set up registers for signal handler */
383 regs->sp = (unsigned long)frame;
384 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
385 regs->ax = (unsigned long)sig;
386 regs->dx = (unsigned long)&frame->info;
387 regs->cx = (unsigned long)&frame->uc;
389 regs->ds = __USER_DS;
390 regs->es = __USER_DS;
391 regs->ss = __USER_DS;
392 regs->cs = __USER_CS;
396 #else /* !CONFIG_X86_32 */
397 static int __setup_rt_frame(int sig, struct ksignal *ksig,
398 sigset_t *set, struct pt_regs *regs)
400 struct rt_sigframe __user *frame;
401 void __user *fp = NULL;
404 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
406 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
409 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
410 if (copy_siginfo_to_user(&frame->info, &ksig->info))
415 /* Create the ucontext. */
417 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
419 put_user_ex(0, &frame->uc.uc_flags);
420 put_user_ex(0, &frame->uc.uc_link);
421 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
423 /* Set up to return from userspace. If provided, use a stub
424 already in userspace. */
425 /* x86-64 should always use SA_RESTORER. */
426 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
427 put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
429 /* could use a vstub here */
432 } put_user_catch(err);
434 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
435 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
440 /* Set up registers for signal handler */
442 /* In case the signal handler was declared without prototypes */
445 /* This also works for non SA_SIGINFO handlers because they expect the
446 next argument after the signal number on the stack. */
447 regs->si = (unsigned long)&frame->info;
448 regs->dx = (unsigned long)&frame->uc;
449 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
451 regs->sp = (unsigned long)frame;
454 * Set up the CS and SS registers to run signal handlers in
455 * 64-bit mode, even if the handler happens to be interrupting
456 * 32-bit or 16-bit code.
458 * SS is subtle. In 64-bit mode, we don't need any particular
459 * SS descriptor, but we do need SS to be valid. It's possible
460 * that the old SS is entirely bogus -- this can happen if the
461 * signal we're trying to deliver is #GP or #SS caused by a bad
464 regs->cs = __USER_CS;
465 regs->ss = __USER_DS;
469 #endif /* CONFIG_X86_32 */
471 static int x32_setup_rt_frame(struct ksignal *ksig,
472 compat_sigset_t *set,
473 struct pt_regs *regs)
475 #ifdef CONFIG_X86_X32_ABI
476 struct rt_sigframe_x32 __user *frame;
477 void __user *restorer;
479 void __user *fpstate = NULL;
481 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
483 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
486 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
487 if (copy_siginfo_to_user32(&frame->info, &ksig->info))
492 /* Create the ucontext. */
494 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
496 put_user_ex(0, &frame->uc.uc_flags);
497 put_user_ex(0, &frame->uc.uc_link);
498 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
499 put_user_ex(0, &frame->uc.uc__pad0);
501 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
502 restorer = ksig->ka.sa.sa_restorer;
504 /* could use a vstub here */
508 put_user_ex(restorer, &frame->pretcode);
509 } put_user_catch(err);
511 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
513 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
518 /* Set up registers for signal handler */
519 regs->sp = (unsigned long) frame;
520 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
522 /* We use the x32 calling convention here... */
523 regs->di = ksig->sig;
524 regs->si = (unsigned long) &frame->info;
525 regs->dx = (unsigned long) &frame->uc;
527 loadsegment(ds, __USER_DS);
528 loadsegment(es, __USER_DS);
530 regs->cs = __USER_CS;
531 regs->ss = __USER_DS;
532 #endif /* CONFIG_X86_X32_ABI */
538 * Do a signal return; undo the signal stack.
541 asmlinkage unsigned long sys_sigreturn(void)
543 struct pt_regs *regs = current_pt_regs();
544 struct sigframe __user *frame;
547 frame = (struct sigframe __user *)(regs->sp - 8);
549 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
551 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
552 && __copy_from_user(&set.sig[1], &frame->extramask,
553 sizeof(frame->extramask))))
556 set_current_blocked(&set);
558 if (restore_sigcontext(regs, &frame->sc))
563 signal_fault(regs, frame, "sigreturn");
567 #endif /* CONFIG_X86_32 */
569 asmlinkage long sys_rt_sigreturn(void)
571 struct pt_regs *regs = current_pt_regs();
572 struct rt_sigframe __user *frame;
575 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
576 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
578 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
581 set_current_blocked(&set);
583 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
586 if (restore_altstack(&frame->uc.uc_stack))
592 signal_fault(regs, frame, "rt_sigreturn");
597 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
599 int usig = ksig->sig;
600 sigset_t *set = sigmask_to_save();
601 compat_sigset_t *cset = (compat_sigset_t *) set;
603 /* Set up the stack frame */
604 if (is_ia32_frame()) {
605 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
606 return ia32_setup_rt_frame(usig, ksig, cset, regs);
608 return ia32_setup_frame(usig, ksig, cset, regs);
609 } else if (is_x32_frame()) {
610 return x32_setup_rt_frame(ksig, cset, regs);
612 return __setup_rt_frame(ksig->sig, ksig, set, regs);
617 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
620 /* Are we from a system call? */
621 if (syscall_get_nr(current, regs) >= 0) {
622 /* If so, check system call restarting.. */
623 switch (syscall_get_error(current, regs)) {
624 case -ERESTART_RESTARTBLOCK:
625 case -ERESTARTNOHAND:
630 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
635 case -ERESTARTNOINTR:
636 regs->ax = regs->orig_ax;
643 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
644 * flag so that register information in the sigcontext is correct.
646 if (unlikely(regs->flags & X86_EFLAGS_TF) &&
647 likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
648 regs->flags &= ~X86_EFLAGS_TF;
650 failed = (setup_rt_frame(ksig, regs) < 0);
653 * Clear the direction flag as per the ABI for function entry.
655 * Clear RF when entering the signal handler, because
656 * it might disable possible debug exception from the
659 * Clear TF when entering the signal handler, but
660 * notify any tracer that was single-stepping it.
661 * The tracer may want to single-step inside the
664 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
666 * Ensure the signal handler starts with the new fpu state.
669 fpu_reset_state(current);
671 signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP));
675 #define NR_restart_syscall __NR_restart_syscall
676 #else /* !CONFIG_X86_32 */
677 #define NR_restart_syscall \
678 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
679 #endif /* CONFIG_X86_32 */
682 * Note that 'init' is a special process: it doesn't get signals it doesn't
683 * want to handle. Thus you cannot kill init even with a SIGKILL even by
686 static void do_signal(struct pt_regs *regs)
690 if (get_signal(&ksig)) {
691 /* Whee! Actually deliver the signal. */
692 handle_signal(&ksig, regs);
696 /* Did we come from a system call? */
697 if (syscall_get_nr(current, regs) >= 0) {
698 /* Restart the system call - no handlers present */
699 switch (syscall_get_error(current, regs)) {
700 case -ERESTARTNOHAND:
702 case -ERESTARTNOINTR:
703 regs->ax = regs->orig_ax;
707 case -ERESTART_RESTARTBLOCK:
708 regs->ax = NR_restart_syscall;
715 * If there's no signal to deliver, we just put the saved sigmask
718 restore_saved_sigmask();
722 * notification of userspace execution resumption
723 * - triggered by the TIF_WORK_MASK flags
726 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
730 if (thread_info_flags & _TIF_UPROBE)
731 uprobe_notify_resume(regs);
733 /* deal with pending signal delivery */
734 if (thread_info_flags & _TIF_SIGPENDING)
737 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
738 clear_thread_flag(TIF_NOTIFY_RESUME);
739 tracehook_notify_resume(regs);
741 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
742 fire_user_return_notifiers();
747 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
749 struct task_struct *me = current;
751 if (show_unhandled_signals && printk_ratelimit()) {
753 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
754 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
755 me->comm, me->pid, where, frame,
756 regs->ip, regs->sp, regs->orig_ax);
757 print_vma_addr(" in ", regs->ip);
761 force_sig(SIGSEGV, me);
764 #ifdef CONFIG_X86_X32_ABI
765 asmlinkage long sys32_x32_rt_sigreturn(void)
767 struct pt_regs *regs = current_pt_regs();
768 struct rt_sigframe_x32 __user *frame;
771 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
773 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
775 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
778 set_current_blocked(&set);
780 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
783 if (compat_restore_altstack(&frame->uc.uc_stack))
789 signal_fault(regs, frame, "x32 rt_sigreturn");