1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
7 * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
8 * 2000-2002 x86-64 support by Andi Kleen
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/sched.h>
14 #include <linux/sched/task_stack.h>
16 #include <linux/smp.h>
17 #include <linux/kernel.h>
18 #include <linux/errno.h>
19 #include <linux/wait.h>
20 #include <linux/tracehook.h>
21 #include <linux/unistd.h>
22 #include <linux/stddef.h>
23 #include <linux/personality.h>
24 #include <linux/uaccess.h>
25 #include <linux/user-return-notifier.h>
26 #include <linux/uprobes.h>
27 #include <linux/context_tracking.h>
28 #include <linux/syscalls.h>
30 #include <asm/processor.h>
31 #include <asm/ucontext.h>
32 #include <asm/fpu/internal.h>
33 #include <asm/fpu/signal.h>
36 #include <asm/sighandling.h>
40 #include <asm/proto.h>
41 #include <asm/ia32_unistd.h>
42 #endif /* CONFIG_X86_64 */
44 #include <asm/syscall.h>
45 #include <asm/sigframe.h>
46 #include <asm/signal.h>
50 * If regs->ss will cause an IRET fault, change it. Otherwise leave it
51 * alone. Using this generally makes no sense unless
52 * user_64bit_mode(regs) would return true.
54 static void force_valid_ss(struct pt_regs *regs)
57 asm volatile ("lar %[old_ss], %[ar]\n\t"
58 "jz 1f\n\t" /* If invalid: */
59 "xorl %[ar], %[ar]\n\t" /* set ar = 0 */
62 : [old_ss] "rm" ((u16)regs->ss));
65 * For a valid 64-bit user context, we need DPL 3, type
66 * read-write data or read-write exp-down data, and S and P
67 * set. We can't use VERW because VERW doesn't check the
70 ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK;
71 if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) &&
72 ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN))
75 # define CONTEXT_COPY_SIZE offsetof(struct sigcontext, reserved1)
77 # define CONTEXT_COPY_SIZE sizeof(struct sigcontext)
80 static int restore_sigcontext(struct pt_regs *regs,
81 struct sigcontext __user *usc,
82 unsigned long uc_flags)
86 /* Always make any pending restarted system calls return -EINTR */
87 current->restart_block.fn = do_no_restart_syscall;
89 if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE))
93 set_user_gs(regs, sc.gs);
97 #endif /* CONFIG_X86_32 */
118 #endif /* CONFIG_X86_64 */
120 /* Get CS/SS and force CPL3 */
121 regs->cs = sc.cs | 0x03;
122 regs->ss = sc.ss | 0x03;
124 regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS);
125 /* disable syscall checks */
130 * Fix up SS if needed for the benefit of old DOSEMU and
133 if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && user_64bit_mode(regs)))
134 force_valid_ss(regs);
137 return fpu__restore_sig((void __user *)sc.fpstate,
138 IS_ENABLED(CONFIG_X86_32));
141 static __always_inline int
142 __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
143 struct pt_regs *regs, unsigned long mask)
146 unsafe_put_user(get_user_gs(regs),
147 (unsigned int __user *)&sc->gs, Efault);
148 unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault);
149 unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault);
150 unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault);
151 #endif /* CONFIG_X86_32 */
153 unsafe_put_user(regs->di, &sc->di, Efault);
154 unsafe_put_user(regs->si, &sc->si, Efault);
155 unsafe_put_user(regs->bp, &sc->bp, Efault);
156 unsafe_put_user(regs->sp, &sc->sp, Efault);
157 unsafe_put_user(regs->bx, &sc->bx, Efault);
158 unsafe_put_user(regs->dx, &sc->dx, Efault);
159 unsafe_put_user(regs->cx, &sc->cx, Efault);
160 unsafe_put_user(regs->ax, &sc->ax, Efault);
162 unsafe_put_user(regs->r8, &sc->r8, Efault);
163 unsafe_put_user(regs->r9, &sc->r9, Efault);
164 unsafe_put_user(regs->r10, &sc->r10, Efault);
165 unsafe_put_user(regs->r11, &sc->r11, Efault);
166 unsafe_put_user(regs->r12, &sc->r12, Efault);
167 unsafe_put_user(regs->r13, &sc->r13, Efault);
168 unsafe_put_user(regs->r14, &sc->r14, Efault);
169 unsafe_put_user(regs->r15, &sc->r15, Efault);
170 #endif /* CONFIG_X86_64 */
172 unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault);
173 unsafe_put_user(current->thread.error_code, &sc->err, Efault);
174 unsafe_put_user(regs->ip, &sc->ip, Efault);
176 unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault);
177 unsafe_put_user(regs->flags, &sc->flags, Efault);
178 unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault);
179 unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault);
180 #else /* !CONFIG_X86_32 */
181 unsafe_put_user(regs->flags, &sc->flags, Efault);
182 unsafe_put_user(regs->cs, &sc->cs, Efault);
183 unsafe_put_user(0, &sc->gs, Efault);
184 unsafe_put_user(0, &sc->fs, Efault);
185 unsafe_put_user(regs->ss, &sc->ss, Efault);
186 #endif /* CONFIG_X86_32 */
188 unsafe_put_user(fpstate, (unsigned long __user *)&sc->fpstate, Efault);
190 /* non-iBCS2 extensions.. */
191 unsafe_put_user(mask, &sc->oldmask, Efault);
192 unsafe_put_user(current->thread.cr2, &sc->cr2, Efault);
198 #define unsafe_put_sigcontext(sc, fp, regs, set, label) \
200 if (__unsafe_setup_sigcontext(sc, fp, regs, set->sig[0])) \
204 #define unsafe_put_sigmask(set, frame, label) \
205 unsafe_put_user(*(__u64 *)(set), \
206 (__u64 __user *)&(frame)->uc.uc_sigmask, \
210 * Set up a signal frame.
214 * Determine which stack to use..
216 static unsigned long align_sigframe(unsigned long sp)
220 * Align the stack pointer according to the i386 ABI,
221 * i.e. so that on function entry ((sp + 4) & 15) == 0.
223 sp = ((sp + 4) & -16ul) - 4;
224 #else /* !CONFIG_X86_32 */
225 sp = round_down(sp, 16) - 8;
231 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
232 void __user **fpstate)
234 /* Default to using normal stack */
235 unsigned long math_size = 0;
236 unsigned long sp = regs->sp;
237 unsigned long buf_fx = 0;
238 int onsigstack = on_sig_stack(sp);
242 if (IS_ENABLED(CONFIG_X86_64))
245 /* This is the X/Open sanctioned signal stack switching. */
246 if (ka->sa.sa_flags & SA_ONSTACK) {
247 if (sas_ss_flags(sp) == 0)
248 sp = current->sas_ss_sp + current->sas_ss_size;
249 } else if (IS_ENABLED(CONFIG_X86_32) &&
251 regs->ss != __USER_DS &&
252 !(ka->sa.sa_flags & SA_RESTORER) &&
253 ka->sa.sa_restorer) {
254 /* This is the legacy signal stack switching. */
255 sp = (unsigned long) ka->sa.sa_restorer;
258 sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),
259 &buf_fx, &math_size);
260 *fpstate = (void __user *)sp;
262 sp = align_sigframe(sp - frame_size);
265 * If we are on the alternate signal stack and would overflow it, don't.
266 * Return an always-bogus address instead so we will die with SIGSEGV.
268 if (onsigstack && !likely(on_sig_stack(sp)))
269 return (void __user *)-1L;
271 /* save i387 and extended state */
272 ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size);
274 return (void __user *)-1L;
276 return (void __user *)sp;
280 static const struct {
284 } __attribute__((packed)) retcode = {
285 0xb858, /* popl %eax; movl $..., %eax */
287 0x80cd, /* int $0x80 */
290 static const struct {
295 } __attribute__((packed)) rt_retcode = {
296 0xb8, /* movl $..., %eax */
298 0x80cd, /* int $0x80 */
303 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
304 struct pt_regs *regs)
306 struct sigframe __user *frame;
307 void __user *restorer;
308 void __user *fp = NULL;
310 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
312 if (!user_access_begin(frame, sizeof(*frame)))
315 unsafe_put_user(sig, &frame->sig, Efault);
316 unsafe_put_sigcontext(&frame->sc, fp, regs, set, Efault);
317 unsafe_put_user(set->sig[1], &frame->extramask[0], Efault);
318 if (current->mm->context.vdso)
319 restorer = current->mm->context.vdso +
320 vdso_image_32.sym___kernel_sigreturn;
322 restorer = &frame->retcode;
323 if (ksig->ka.sa.sa_flags & SA_RESTORER)
324 restorer = ksig->ka.sa.sa_restorer;
326 /* Set up to return from userspace. */
327 unsafe_put_user(restorer, &frame->pretcode, Efault);
330 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
332 * WE DO NOT USE IT ANY MORE! It's only left here for historical
333 * reasons and because gdb uses it as a signature to notice
334 * signal handler stack frames.
336 unsafe_put_user(*((u64 *)&retcode), (u64 *)frame->retcode, Efault);
339 /* Set up registers for signal handler */
340 regs->sp = (unsigned long)frame;
341 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
342 regs->ax = (unsigned long)sig;
346 regs->ds = __USER_DS;
347 regs->es = __USER_DS;
348 regs->ss = __USER_DS;
349 regs->cs = __USER_CS;
358 static int __setup_rt_frame(int sig, struct ksignal *ksig,
359 sigset_t *set, struct pt_regs *regs)
361 struct rt_sigframe __user *frame;
362 void __user *restorer;
363 void __user *fp = NULL;
365 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
367 if (!user_access_begin(frame, sizeof(*frame)))
370 unsafe_put_user(sig, &frame->sig, Efault);
371 unsafe_put_user(&frame->info, &frame->pinfo, Efault);
372 unsafe_put_user(&frame->uc, &frame->puc, Efault);
374 /* Create the ucontext. */
375 if (static_cpu_has(X86_FEATURE_XSAVE))
376 unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault);
378 unsafe_put_user(0, &frame->uc.uc_flags, Efault);
379 unsafe_put_user(0, &frame->uc.uc_link, Efault);
380 unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
382 /* Set up to return from userspace. */
383 restorer = current->mm->context.vdso +
384 vdso_image_32.sym___kernel_rt_sigreturn;
385 if (ksig->ka.sa.sa_flags & SA_RESTORER)
386 restorer = ksig->ka.sa.sa_restorer;
387 unsafe_put_user(restorer, &frame->pretcode, Efault);
390 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
392 * WE DO NOT USE IT ANY MORE! It's only left here for historical
393 * reasons and because gdb uses it as a signature to notice
394 * signal handler stack frames.
396 unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault);
397 unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
398 unsafe_put_sigmask(set, frame, Efault);
401 if (copy_siginfo_to_user(&frame->info, &ksig->info))
404 /* Set up registers for signal handler */
405 regs->sp = (unsigned long)frame;
406 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
407 regs->ax = (unsigned long)sig;
408 regs->dx = (unsigned long)&frame->info;
409 regs->cx = (unsigned long)&frame->uc;
411 regs->ds = __USER_DS;
412 regs->es = __USER_DS;
413 regs->ss = __USER_DS;
414 regs->cs = __USER_CS;
421 #else /* !CONFIG_X86_32 */
422 static unsigned long frame_uc_flags(struct pt_regs *regs)
426 if (boot_cpu_has(X86_FEATURE_XSAVE))
427 flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS;
429 flags = UC_SIGCONTEXT_SS;
431 if (likely(user_64bit_mode(regs)))
432 flags |= UC_STRICT_RESTORE_SS;
437 static int __setup_rt_frame(int sig, struct ksignal *ksig,
438 sigset_t *set, struct pt_regs *regs)
440 struct rt_sigframe __user *frame;
441 void __user *fp = NULL;
442 unsigned long uc_flags;
444 /* x86-64 should always use SA_RESTORER. */
445 if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
448 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
449 uc_flags = frame_uc_flags(regs);
451 if (!user_access_begin(frame, sizeof(*frame)))
454 /* Create the ucontext. */
455 unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
456 unsafe_put_user(0, &frame->uc.uc_link, Efault);
457 unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
459 /* Set up to return from userspace. If provided, use a stub
460 already in userspace. */
461 unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault);
462 unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
463 unsafe_put_sigmask(set, frame, Efault);
466 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
467 if (copy_siginfo_to_user(&frame->info, &ksig->info))
471 /* Set up registers for signal handler */
473 /* In case the signal handler was declared without prototypes */
476 /* This also works for non SA_SIGINFO handlers because they expect the
477 next argument after the signal number on the stack. */
478 regs->si = (unsigned long)&frame->info;
479 regs->dx = (unsigned long)&frame->uc;
480 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
482 regs->sp = (unsigned long)frame;
485 * Set up the CS and SS registers to run signal handlers in
486 * 64-bit mode, even if the handler happens to be interrupting
487 * 32-bit or 16-bit code.
489 * SS is subtle. In 64-bit mode, we don't need any particular
490 * SS descriptor, but we do need SS to be valid. It's possible
491 * that the old SS is entirely bogus -- this can happen if the
492 * signal we're trying to deliver is #GP or #SS caused by a bad
493 * SS value. We also have a compatbility issue here: DOSEMU
494 * relies on the contents of the SS register indicating the
495 * SS value at the time of the signal, even though that code in
496 * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU
497 * avoids relying on sigreturn to restore SS; instead it uses
498 * a trampoline.) So we do our best: if the old SS was valid,
499 * we keep it. Otherwise we replace it.
501 regs->cs = __USER_CS;
503 if (unlikely(regs->ss != __USER_DS))
504 force_valid_ss(regs);
512 #endif /* CONFIG_X86_32 */
514 static int x32_setup_rt_frame(struct ksignal *ksig,
515 compat_sigset_t *set,
516 struct pt_regs *regs)
518 #ifdef CONFIG_X86_X32_ABI
519 struct rt_sigframe_x32 __user *frame;
520 unsigned long uc_flags;
521 void __user *restorer;
522 void __user *fp = NULL;
524 if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
527 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
529 uc_flags = frame_uc_flags(regs);
531 if (!user_access_begin(frame, sizeof(*frame)))
534 /* Create the ucontext. */
535 unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
536 unsafe_put_user(0, &frame->uc.uc_link, Efault);
537 unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
538 unsafe_put_user(0, &frame->uc.uc__pad0, Efault);
539 restorer = ksig->ka.sa.sa_restorer;
540 unsafe_put_user(restorer, (unsigned long __user *)&frame->pretcode, Efault);
541 unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
542 unsafe_put_sigmask(set, frame, Efault);
545 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
546 if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true))
550 /* Set up registers for signal handler */
551 regs->sp = (unsigned long) frame;
552 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
554 /* We use the x32 calling convention here... */
555 regs->di = ksig->sig;
556 regs->si = (unsigned long) &frame->info;
557 regs->dx = (unsigned long) &frame->uc;
559 loadsegment(ds, __USER_DS);
560 loadsegment(es, __USER_DS);
562 regs->cs = __USER_CS;
563 regs->ss = __USER_DS;
564 #endif /* CONFIG_X86_X32_ABI */
567 #ifdef CONFIG_X86_X32_ABI
575 * Do a signal return; undo the signal stack.
578 SYSCALL_DEFINE0(sigreturn)
580 struct pt_regs *regs = current_pt_regs();
581 struct sigframe __user *frame;
584 frame = (struct sigframe __user *)(regs->sp - 8);
586 if (!access_ok(frame, sizeof(*frame)))
588 if (__get_user(set.sig[0], &frame->sc.oldmask) ||
589 __get_user(set.sig[1], &frame->extramask[0]))
592 set_current_blocked(&set);
595 * x86_32 has no uc_flags bits relevant to restore_sigcontext.
596 * Save a few cycles by skipping the __get_user.
598 if (restore_sigcontext(regs, &frame->sc, 0))
603 signal_fault(regs, frame, "sigreturn");
607 #endif /* CONFIG_X86_32 */
609 SYSCALL_DEFINE0(rt_sigreturn)
611 struct pt_regs *regs = current_pt_regs();
612 struct rt_sigframe __user *frame;
614 unsigned long uc_flags;
616 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
617 if (!access_ok(frame, sizeof(*frame)))
619 if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask))
621 if (__get_user(uc_flags, &frame->uc.uc_flags))
624 set_current_blocked(&set);
626 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
629 if (restore_altstack(&frame->uc.uc_stack))
635 signal_fault(regs, frame, "rt_sigreturn");
639 static inline int is_ia32_compat_frame(struct ksignal *ksig)
641 return IS_ENABLED(CONFIG_IA32_EMULATION) &&
642 ksig->ka.sa.sa_flags & SA_IA32_ABI;
645 static inline int is_ia32_frame(struct ksignal *ksig)
647 return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);
650 static inline int is_x32_frame(struct ksignal *ksig)
652 return IS_ENABLED(CONFIG_X86_X32_ABI) &&
653 ksig->ka.sa.sa_flags & SA_X32_ABI;
657 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
659 int usig = ksig->sig;
660 sigset_t *set = sigmask_to_save();
661 compat_sigset_t *cset = (compat_sigset_t *) set;
663 /* Perform fixup for the pre-signal frame. */
664 rseq_signal_deliver(ksig, regs);
666 /* Set up the stack frame */
667 if (is_ia32_frame(ksig)) {
668 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
669 return ia32_setup_rt_frame(usig, ksig, cset, regs);
671 return ia32_setup_frame(usig, ksig, cset, regs);
672 } else if (is_x32_frame(ksig)) {
673 return x32_setup_rt_frame(ksig, cset, regs);
675 return __setup_rt_frame(ksig->sig, ksig, set, regs);
680 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
682 bool stepping, failed;
683 struct fpu *fpu = ¤t->thread.fpu;
685 if (v8086_mode(regs))
686 save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL);
688 /* Are we from a system call? */
689 if (syscall_get_nr(current, regs) >= 0) {
690 /* If so, check system call restarting.. */
691 switch (syscall_get_error(current, regs)) {
692 case -ERESTART_RESTARTBLOCK:
693 case -ERESTARTNOHAND:
698 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
703 case -ERESTARTNOINTR:
704 regs->ax = regs->orig_ax;
711 * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
712 * so that register information in the sigcontext is correct and
713 * then notify the tracer before entering the signal handler.
715 stepping = test_thread_flag(TIF_SINGLESTEP);
717 user_disable_single_step(current);
719 failed = (setup_rt_frame(ksig, regs) < 0);
722 * Clear the direction flag as per the ABI for function entry.
724 * Clear RF when entering the signal handler, because
725 * it might disable possible debug exception from the
728 * Clear TF for the case when it wasn't set by debugger to
729 * avoid the recursive send_sigtrap() in SIGTRAP handler.
731 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
733 * Ensure the signal handler starts with the new fpu state.
737 signal_setup_done(failed, ksig, stepping);
740 static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
743 * This function is fundamentally broken as currently
746 * The idea is that we want to trigger a call to the
747 * restart_block() syscall and that we want in_ia32_syscall(),
748 * in_x32_syscall(), etc. to match whatever they were in the
749 * syscall being restarted. We assume that the syscall
750 * instruction at (regs->ip - 2) matches whatever syscall
751 * instruction we used to enter in the first place.
753 * The problem is that we can get here when ptrace pokes
754 * syscall-like values into regs even if we're not in a syscall
757 * For now, we maintain historical behavior and guess based on
758 * stored state. We could do better by saving the actual
759 * syscall arch in restart_block or (with caveats on x32) by
760 * checking if regs->ip points to 'int $0x80'. The current
761 * behavior is incorrect if a tracer has a different bitness
764 #ifdef CONFIG_IA32_EMULATION
765 if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED))
766 return __NR_ia32_restart_syscall;
768 #ifdef CONFIG_X86_X32_ABI
769 return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
771 return __NR_restart_syscall;
776 * Note that 'init' is a special process: it doesn't get signals it doesn't
777 * want to handle. Thus you cannot kill init even with a SIGKILL even by
780 void do_signal(struct pt_regs *regs)
784 if (get_signal(&ksig)) {
785 /* Whee! Actually deliver the signal. */
786 handle_signal(&ksig, regs);
790 /* Did we come from a system call? */
791 if (syscall_get_nr(current, regs) >= 0) {
792 /* Restart the system call - no handlers present */
793 switch (syscall_get_error(current, regs)) {
794 case -ERESTARTNOHAND:
796 case -ERESTARTNOINTR:
797 regs->ax = regs->orig_ax;
801 case -ERESTART_RESTARTBLOCK:
802 regs->ax = get_nr_restart_syscall(regs);
809 * If there's no signal to deliver, we just put the saved sigmask
812 restore_saved_sigmask();
815 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
817 struct task_struct *me = current;
819 if (show_unhandled_signals && printk_ratelimit()) {
821 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
822 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
823 me->comm, me->pid, where, frame,
824 regs->ip, regs->sp, regs->orig_ax);
825 print_vma_addr(KERN_CONT " in ", regs->ip);
832 #ifdef CONFIG_X86_X32_ABI
833 COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn)
835 struct pt_regs *regs = current_pt_regs();
836 struct rt_sigframe_x32 __user *frame;
838 unsigned long uc_flags;
840 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
842 if (!access_ok(frame, sizeof(*frame)))
844 if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
846 if (__get_user(uc_flags, &frame->uc.uc_flags))
849 set_current_blocked(&set);
851 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
854 if (compat_restore_altstack(&frame->uc.uc_stack))
860 signal_fault(regs, frame, "x32 rt_sigreturn");