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>
29 #include <asm/fpu/internal.h>
30 #include <asm/fpu/signal.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 |= fpu__restore_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);
202 struct fpu *fpu = ¤t->thread.fpu;
205 if (config_enabled(CONFIG_X86_64))
209 /* This is the X/Open sanctioned signal stack switching. */
210 if (ka->sa.sa_flags & SA_ONSTACK) {
211 if (current->sas_ss_size)
212 sp = current->sas_ss_sp + current->sas_ss_size;
213 } else if (config_enabled(CONFIG_X86_32) &&
214 (regs->ss & 0xffff) != __USER_DS &&
215 !(ka->sa.sa_flags & SA_RESTORER) &&
216 ka->sa.sa_restorer) {
217 /* This is the legacy signal stack switching. */
218 sp = (unsigned long) ka->sa.sa_restorer;
222 if (fpu->fpstate_active) {
223 sp = fpu__alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
224 &buf_fx, &math_size);
225 *fpstate = (void __user *)sp;
228 sp = align_sigframe(sp - frame_size);
231 * If we are on the alternate signal stack and would overflow it, don't.
232 * Return an always-bogus address instead so we will die with SIGSEGV.
234 if (onsigstack && !likely(on_sig_stack(sp)))
235 return (void __user *)-1L;
237 /* save i387 and extended state */
238 if (fpu->fpstate_active &&
239 copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0)
240 return (void __user *)-1L;
242 return (void __user *)sp;
246 static const struct {
250 } __attribute__((packed)) retcode = {
251 0xb858, /* popl %eax; movl $..., %eax */
253 0x80cd, /* int $0x80 */
256 static const struct {
261 } __attribute__((packed)) rt_retcode = {
262 0xb8, /* movl $..., %eax */
264 0x80cd, /* int $0x80 */
269 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
270 struct pt_regs *regs)
272 struct sigframe __user *frame;
273 void __user *restorer;
275 void __user *fpstate = NULL;
277 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
279 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
282 if (__put_user(sig, &frame->sig))
285 if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
288 if (_NSIG_WORDS > 1) {
289 if (__copy_to_user(&frame->extramask, &set->sig[1],
290 sizeof(frame->extramask)))
294 if (current->mm->context.vdso)
295 restorer = current->mm->context.vdso +
296 selected_vdso32->sym___kernel_sigreturn;
298 restorer = &frame->retcode;
299 if (ksig->ka.sa.sa_flags & SA_RESTORER)
300 restorer = ksig->ka.sa.sa_restorer;
302 /* Set up to return from userspace. */
303 err |= __put_user(restorer, &frame->pretcode);
306 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
308 * WE DO NOT USE IT ANY MORE! It's only left here for historical
309 * reasons and because gdb uses it as a signature to notice
310 * signal handler stack frames.
312 err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
317 /* Set up registers for signal handler */
318 regs->sp = (unsigned long)frame;
319 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
320 regs->ax = (unsigned long)sig;
324 regs->ds = __USER_DS;
325 regs->es = __USER_DS;
326 regs->ss = __USER_DS;
327 regs->cs = __USER_CS;
332 static int __setup_rt_frame(int sig, struct ksignal *ksig,
333 sigset_t *set, struct pt_regs *regs)
335 struct rt_sigframe __user *frame;
336 void __user *restorer;
338 void __user *fpstate = NULL;
340 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
342 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
346 put_user_ex(sig, &frame->sig);
347 put_user_ex(&frame->info, &frame->pinfo);
348 put_user_ex(&frame->uc, &frame->puc);
350 /* Create the ucontext. */
352 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
354 put_user_ex(0, &frame->uc.uc_flags);
355 put_user_ex(0, &frame->uc.uc_link);
356 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
358 /* Set up to return from userspace. */
359 restorer = current->mm->context.vdso +
360 selected_vdso32->sym___kernel_rt_sigreturn;
361 if (ksig->ka.sa.sa_flags & SA_RESTORER)
362 restorer = ksig->ka.sa.sa_restorer;
363 put_user_ex(restorer, &frame->pretcode);
366 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
368 * WE DO NOT USE IT ANY MORE! It's only left here for historical
369 * reasons and because gdb uses it as a signature to notice
370 * signal handler stack frames.
372 put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
373 } put_user_catch(err);
375 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
376 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
378 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
383 /* Set up registers for signal handler */
384 regs->sp = (unsigned long)frame;
385 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
386 regs->ax = (unsigned long)sig;
387 regs->dx = (unsigned long)&frame->info;
388 regs->cx = (unsigned long)&frame->uc;
390 regs->ds = __USER_DS;
391 regs->es = __USER_DS;
392 regs->ss = __USER_DS;
393 regs->cs = __USER_CS;
397 #else /* !CONFIG_X86_32 */
398 static int __setup_rt_frame(int sig, struct ksignal *ksig,
399 sigset_t *set, struct pt_regs *regs)
401 struct rt_sigframe __user *frame;
402 void __user *fp = NULL;
405 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
407 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
410 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
411 if (copy_siginfo_to_user(&frame->info, &ksig->info))
416 /* Create the ucontext. */
418 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
420 put_user_ex(0, &frame->uc.uc_flags);
421 put_user_ex(0, &frame->uc.uc_link);
422 save_altstack_ex(&frame->uc.uc_stack, regs->sp);
424 /* Set up to return from userspace. If provided, use a stub
425 already in userspace. */
426 /* x86-64 should always use SA_RESTORER. */
427 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
428 put_user_ex(ksig->ka.sa.sa_restorer, &frame->pretcode);
430 /* could use a vstub here */
433 } put_user_catch(err);
435 err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
436 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
441 /* Set up registers for signal handler */
443 /* In case the signal handler was declared without prototypes */
446 /* This also works for non SA_SIGINFO handlers because they expect the
447 next argument after the signal number on the stack. */
448 regs->si = (unsigned long)&frame->info;
449 regs->dx = (unsigned long)&frame->uc;
450 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
452 regs->sp = (unsigned long)frame;
455 * Set up the CS and SS registers to run signal handlers in
456 * 64-bit mode, even if the handler happens to be interrupting
457 * 32-bit or 16-bit code.
459 * SS is subtle. In 64-bit mode, we don't need any particular
460 * SS descriptor, but we do need SS to be valid. It's possible
461 * that the old SS is entirely bogus -- this can happen if the
462 * signal we're trying to deliver is #GP or #SS caused by a bad
465 regs->cs = __USER_CS;
466 regs->ss = __USER_DS;
470 #endif /* CONFIG_X86_32 */
472 static int x32_setup_rt_frame(struct ksignal *ksig,
473 compat_sigset_t *set,
474 struct pt_regs *regs)
476 #ifdef CONFIG_X86_X32_ABI
477 struct rt_sigframe_x32 __user *frame;
478 void __user *restorer;
480 void __user *fpstate = NULL;
482 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fpstate);
484 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
487 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
488 if (copy_siginfo_to_user32(&frame->info, &ksig->info))
493 /* Create the ucontext. */
495 put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
497 put_user_ex(0, &frame->uc.uc_flags);
498 put_user_ex(0, &frame->uc.uc_link);
499 compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
500 put_user_ex(0, &frame->uc.uc__pad0);
502 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
503 restorer = ksig->ka.sa.sa_restorer;
505 /* could use a vstub here */
509 put_user_ex(restorer, &frame->pretcode);
510 } put_user_catch(err);
512 err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
514 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
519 /* Set up registers for signal handler */
520 regs->sp = (unsigned long) frame;
521 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
523 /* We use the x32 calling convention here... */
524 regs->di = ksig->sig;
525 regs->si = (unsigned long) &frame->info;
526 regs->dx = (unsigned long) &frame->uc;
528 loadsegment(ds, __USER_DS);
529 loadsegment(es, __USER_DS);
531 regs->cs = __USER_CS;
532 regs->ss = __USER_DS;
533 #endif /* CONFIG_X86_X32_ABI */
539 * Do a signal return; undo the signal stack.
542 asmlinkage unsigned long sys_sigreturn(void)
544 struct pt_regs *regs = current_pt_regs();
545 struct sigframe __user *frame;
548 frame = (struct sigframe __user *)(regs->sp - 8);
550 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
552 if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
553 && __copy_from_user(&set.sig[1], &frame->extramask,
554 sizeof(frame->extramask))))
557 set_current_blocked(&set);
559 if (restore_sigcontext(regs, &frame->sc))
564 signal_fault(regs, frame, "sigreturn");
568 #endif /* CONFIG_X86_32 */
570 asmlinkage long sys_rt_sigreturn(void)
572 struct pt_regs *regs = current_pt_regs();
573 struct rt_sigframe __user *frame;
576 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
577 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
579 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
582 set_current_blocked(&set);
584 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
587 if (restore_altstack(&frame->uc.uc_stack))
593 signal_fault(regs, frame, "rt_sigreturn");
597 static inline int is_ia32_compat_frame(void)
599 return config_enabled(CONFIG_IA32_EMULATION) &&
600 test_thread_flag(TIF_IA32);
603 static inline int is_ia32_frame(void)
605 return config_enabled(CONFIG_X86_32) || is_ia32_compat_frame();
608 static inline int is_x32_frame(void)
610 return config_enabled(CONFIG_X86_X32_ABI) && test_thread_flag(TIF_X32);
614 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
616 int usig = ksig->sig;
617 sigset_t *set = sigmask_to_save();
618 compat_sigset_t *cset = (compat_sigset_t *) set;
620 /* Set up the stack frame */
621 if (is_ia32_frame()) {
622 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
623 return ia32_setup_rt_frame(usig, ksig, cset, regs);
625 return ia32_setup_frame(usig, ksig, cset, regs);
626 } else if (is_x32_frame()) {
627 return x32_setup_rt_frame(ksig, cset, regs);
629 return __setup_rt_frame(ksig->sig, ksig, set, regs);
634 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
636 bool stepping, failed;
637 struct fpu *fpu = ¤t->thread.fpu;
639 /* Are we from a system call? */
640 if (syscall_get_nr(current, regs) >= 0) {
641 /* If so, check system call restarting.. */
642 switch (syscall_get_error(current, regs)) {
643 case -ERESTART_RESTARTBLOCK:
644 case -ERESTARTNOHAND:
649 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
654 case -ERESTARTNOINTR:
655 regs->ax = regs->orig_ax;
662 * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
663 * so that register information in the sigcontext is correct and
664 * then notify the tracer before entering the signal handler.
666 stepping = test_thread_flag(TIF_SINGLESTEP);
668 user_disable_single_step(current);
670 failed = (setup_rt_frame(ksig, regs) < 0);
673 * Clear the direction flag as per the ABI for function entry.
675 * Clear RF when entering the signal handler, because
676 * it might disable possible debug exception from the
679 * Clear TF for the case when it wasn't set by debugger to
680 * avoid the recursive send_sigtrap() in SIGTRAP handler.
682 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
684 * Ensure the signal handler starts with the new fpu state.
686 if (fpu->fpstate_active)
689 signal_setup_done(failed, ksig, stepping);
693 #define NR_restart_syscall __NR_restart_syscall
694 #else /* !CONFIG_X86_32 */
695 #define NR_restart_syscall \
696 test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
697 #endif /* CONFIG_X86_32 */
700 * Note that 'init' is a special process: it doesn't get signals it doesn't
701 * want to handle. Thus you cannot kill init even with a SIGKILL even by
704 static void do_signal(struct pt_regs *regs)
708 if (get_signal(&ksig)) {
709 /* Whee! Actually deliver the signal. */
710 handle_signal(&ksig, regs);
714 /* Did we come from a system call? */
715 if (syscall_get_nr(current, regs) >= 0) {
716 /* Restart the system call - no handlers present */
717 switch (syscall_get_error(current, regs)) {
718 case -ERESTARTNOHAND:
720 case -ERESTARTNOINTR:
721 regs->ax = regs->orig_ax;
725 case -ERESTART_RESTARTBLOCK:
726 regs->ax = NR_restart_syscall;
733 * If there's no signal to deliver, we just put the saved sigmask
736 restore_saved_sigmask();
740 * notification of userspace execution resumption
741 * - triggered by the TIF_WORK_MASK flags
744 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
748 if (thread_info_flags & _TIF_UPROBE)
749 uprobe_notify_resume(regs);
751 /* deal with pending signal delivery */
752 if (thread_info_flags & _TIF_SIGPENDING)
755 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
756 clear_thread_flag(TIF_NOTIFY_RESUME);
757 tracehook_notify_resume(regs);
759 if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
760 fire_user_return_notifiers();
765 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
767 struct task_struct *me = current;
769 if (show_unhandled_signals && printk_ratelimit()) {
771 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
772 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
773 me->comm, me->pid, where, frame,
774 regs->ip, regs->sp, regs->orig_ax);
775 print_vma_addr(" in ", regs->ip);
779 force_sig(SIGSEGV, me);
782 #ifdef CONFIG_X86_X32_ABI
783 asmlinkage long sys32_x32_rt_sigreturn(void)
785 struct pt_regs *regs = current_pt_regs();
786 struct rt_sigframe_x32 __user *frame;
789 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
791 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
793 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
796 set_current_blocked(&set);
798 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
801 if (compat_restore_altstack(&frame->uc.uc_stack))
807 signal_fault(regs, frame, "x32 rt_sigreturn");