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/entry-common.h>
29 #include <linux/syscalls.h>
31 #include <asm/processor.h>
32 #include <asm/ucontext.h>
33 #include <asm/fpu/internal.h>
34 #include <asm/fpu/signal.h>
37 #include <asm/sighandling.h>
41 #include <linux/compat.h>
42 #include <asm/proto.h>
43 #include <asm/ia32_unistd.h>
44 #endif /* CONFIG_X86_64 */
46 #include <asm/syscall.h>
47 #include <asm/sigframe.h>
48 #include <asm/signal.h>
52 * If regs->ss will cause an IRET fault, change it. Otherwise leave it
53 * alone. Using this generally makes no sense unless
54 * user_64bit_mode(regs) would return true.
56 static void force_valid_ss(struct pt_regs *regs)
59 asm volatile ("lar %[old_ss], %[ar]\n\t"
60 "jz 1f\n\t" /* If invalid: */
61 "xorl %[ar], %[ar]\n\t" /* set ar = 0 */
64 : [old_ss] "rm" ((u16)regs->ss));
67 * For a valid 64-bit user context, we need DPL 3, type
68 * read-write data or read-write exp-down data, and S and P
69 * set. We can't use VERW because VERW doesn't check the
72 ar &= AR_DPL_MASK | AR_S | AR_P | AR_TYPE_MASK;
73 if (ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA) &&
74 ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN))
77 # define CONTEXT_COPY_SIZE offsetof(struct sigcontext, reserved1)
79 # define CONTEXT_COPY_SIZE sizeof(struct sigcontext)
82 static int restore_sigcontext(struct pt_regs *regs,
83 struct sigcontext __user *usc,
84 unsigned long uc_flags)
88 /* Always make any pending restarted system calls return -EINTR */
89 current->restart_block.fn = do_no_restart_syscall;
91 if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE))
95 set_user_gs(regs, sc.gs);
99 #endif /* CONFIG_X86_32 */
120 #endif /* CONFIG_X86_64 */
122 /* Get CS/SS and force CPL3 */
123 regs->cs = sc.cs | 0x03;
124 regs->ss = sc.ss | 0x03;
126 regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS);
127 /* disable syscall checks */
132 * Fix up SS if needed for the benefit of old DOSEMU and
135 if (unlikely(!(uc_flags & UC_STRICT_RESTORE_SS) && user_64bit_mode(regs)))
136 force_valid_ss(regs);
139 return fpu__restore_sig((void __user *)sc.fpstate,
140 IS_ENABLED(CONFIG_X86_32));
143 static __always_inline int
144 __unsafe_setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
145 struct pt_regs *regs, unsigned long mask)
148 unsafe_put_user(get_user_gs(regs),
149 (unsigned int __user *)&sc->gs, Efault);
150 unsafe_put_user(regs->fs, (unsigned int __user *)&sc->fs, Efault);
151 unsafe_put_user(regs->es, (unsigned int __user *)&sc->es, Efault);
152 unsafe_put_user(regs->ds, (unsigned int __user *)&sc->ds, Efault);
153 #endif /* CONFIG_X86_32 */
155 unsafe_put_user(regs->di, &sc->di, Efault);
156 unsafe_put_user(regs->si, &sc->si, Efault);
157 unsafe_put_user(regs->bp, &sc->bp, Efault);
158 unsafe_put_user(regs->sp, &sc->sp, Efault);
159 unsafe_put_user(regs->bx, &sc->bx, Efault);
160 unsafe_put_user(regs->dx, &sc->dx, Efault);
161 unsafe_put_user(regs->cx, &sc->cx, Efault);
162 unsafe_put_user(regs->ax, &sc->ax, Efault);
164 unsafe_put_user(regs->r8, &sc->r8, Efault);
165 unsafe_put_user(regs->r9, &sc->r9, Efault);
166 unsafe_put_user(regs->r10, &sc->r10, Efault);
167 unsafe_put_user(regs->r11, &sc->r11, Efault);
168 unsafe_put_user(regs->r12, &sc->r12, Efault);
169 unsafe_put_user(regs->r13, &sc->r13, Efault);
170 unsafe_put_user(regs->r14, &sc->r14, Efault);
171 unsafe_put_user(regs->r15, &sc->r15, Efault);
172 #endif /* CONFIG_X86_64 */
174 unsafe_put_user(current->thread.trap_nr, &sc->trapno, Efault);
175 unsafe_put_user(current->thread.error_code, &sc->err, Efault);
176 unsafe_put_user(regs->ip, &sc->ip, Efault);
178 unsafe_put_user(regs->cs, (unsigned int __user *)&sc->cs, Efault);
179 unsafe_put_user(regs->flags, &sc->flags, Efault);
180 unsafe_put_user(regs->sp, &sc->sp_at_signal, Efault);
181 unsafe_put_user(regs->ss, (unsigned int __user *)&sc->ss, Efault);
182 #else /* !CONFIG_X86_32 */
183 unsafe_put_user(regs->flags, &sc->flags, Efault);
184 unsafe_put_user(regs->cs, &sc->cs, Efault);
185 unsafe_put_user(0, &sc->gs, Efault);
186 unsafe_put_user(0, &sc->fs, Efault);
187 unsafe_put_user(regs->ss, &sc->ss, Efault);
188 #endif /* CONFIG_X86_32 */
190 unsafe_put_user(fpstate, (unsigned long __user *)&sc->fpstate, Efault);
192 /* non-iBCS2 extensions.. */
193 unsafe_put_user(mask, &sc->oldmask, Efault);
194 unsafe_put_user(current->thread.cr2, &sc->cr2, Efault);
200 #define unsafe_put_sigcontext(sc, fp, regs, set, label) \
202 if (__unsafe_setup_sigcontext(sc, fp, regs, set->sig[0])) \
206 #define unsafe_put_sigmask(set, frame, label) \
207 unsafe_put_user(*(__u64 *)(set), \
208 (__u64 __user *)&(frame)->uc.uc_sigmask, \
212 * Set up a signal frame.
216 * Determine which stack to use..
218 static unsigned long align_sigframe(unsigned long sp)
222 * Align the stack pointer according to the i386 ABI,
223 * i.e. so that on function entry ((sp + 4) & 15) == 0.
225 sp = ((sp + 4) & -16ul) - 4;
226 #else /* !CONFIG_X86_32 */
227 sp = round_down(sp, 16) - 8;
233 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
234 void __user **fpstate)
236 /* Default to using normal stack */
237 unsigned long math_size = 0;
238 unsigned long sp = regs->sp;
239 unsigned long buf_fx = 0;
240 int onsigstack = on_sig_stack(sp);
244 if (IS_ENABLED(CONFIG_X86_64))
247 /* This is the X/Open sanctioned signal stack switching. */
248 if (ka->sa.sa_flags & SA_ONSTACK) {
249 if (sas_ss_flags(sp) == 0)
250 sp = current->sas_ss_sp + current->sas_ss_size;
251 } else if (IS_ENABLED(CONFIG_X86_32) &&
253 regs->ss != __USER_DS &&
254 !(ka->sa.sa_flags & SA_RESTORER) &&
255 ka->sa.sa_restorer) {
256 /* This is the legacy signal stack switching. */
257 sp = (unsigned long) ka->sa.sa_restorer;
260 sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),
261 &buf_fx, &math_size);
262 *fpstate = (void __user *)sp;
264 sp = align_sigframe(sp - frame_size);
267 * If we are on the alternate signal stack and would overflow it, don't.
268 * Return an always-bogus address instead so we will die with SIGSEGV.
270 if (onsigstack && !likely(on_sig_stack(sp)))
271 return (void __user *)-1L;
273 /* save i387 and extended state */
274 ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size);
276 return (void __user *)-1L;
278 return (void __user *)sp;
282 static const struct {
286 } __attribute__((packed)) retcode = {
287 0xb858, /* popl %eax; movl $..., %eax */
289 0x80cd, /* int $0x80 */
292 static const struct {
297 } __attribute__((packed)) rt_retcode = {
298 0xb8, /* movl $..., %eax */
300 0x80cd, /* int $0x80 */
305 __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
306 struct pt_regs *regs)
308 struct sigframe __user *frame;
309 void __user *restorer;
310 void __user *fp = NULL;
312 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
314 if (!user_access_begin(frame, sizeof(*frame)))
317 unsafe_put_user(sig, &frame->sig, Efault);
318 unsafe_put_sigcontext(&frame->sc, fp, regs, set, Efault);
319 unsafe_put_user(set->sig[1], &frame->extramask[0], Efault);
320 if (current->mm->context.vdso)
321 restorer = current->mm->context.vdso +
322 vdso_image_32.sym___kernel_sigreturn;
324 restorer = &frame->retcode;
325 if (ksig->ka.sa.sa_flags & SA_RESTORER)
326 restorer = ksig->ka.sa.sa_restorer;
328 /* Set up to return from userspace. */
329 unsafe_put_user(restorer, &frame->pretcode, Efault);
332 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
334 * WE DO NOT USE IT ANY MORE! It's only left here for historical
335 * reasons and because gdb uses it as a signature to notice
336 * signal handler stack frames.
338 unsafe_put_user(*((u64 *)&retcode), (u64 *)frame->retcode, Efault);
341 /* Set up registers for signal handler */
342 regs->sp = (unsigned long)frame;
343 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
344 regs->ax = (unsigned long)sig;
348 regs->ds = __USER_DS;
349 regs->es = __USER_DS;
350 regs->ss = __USER_DS;
351 regs->cs = __USER_CS;
360 static int __setup_rt_frame(int sig, struct ksignal *ksig,
361 sigset_t *set, struct pt_regs *regs)
363 struct rt_sigframe __user *frame;
364 void __user *restorer;
365 void __user *fp = NULL;
367 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
369 if (!user_access_begin(frame, sizeof(*frame)))
372 unsafe_put_user(sig, &frame->sig, Efault);
373 unsafe_put_user(&frame->info, &frame->pinfo, Efault);
374 unsafe_put_user(&frame->uc, &frame->puc, Efault);
376 /* Create the ucontext. */
377 if (static_cpu_has(X86_FEATURE_XSAVE))
378 unsafe_put_user(UC_FP_XSTATE, &frame->uc.uc_flags, Efault);
380 unsafe_put_user(0, &frame->uc.uc_flags, Efault);
381 unsafe_put_user(0, &frame->uc.uc_link, Efault);
382 unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
384 /* Set up to return from userspace. */
385 restorer = current->mm->context.vdso +
386 vdso_image_32.sym___kernel_rt_sigreturn;
387 if (ksig->ka.sa.sa_flags & SA_RESTORER)
388 restorer = ksig->ka.sa.sa_restorer;
389 unsafe_put_user(restorer, &frame->pretcode, Efault);
392 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
394 * WE DO NOT USE IT ANY MORE! It's only left here for historical
395 * reasons and because gdb uses it as a signature to notice
396 * signal handler stack frames.
398 unsafe_put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode, Efault);
399 unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
400 unsafe_put_sigmask(set, frame, Efault);
403 if (copy_siginfo_to_user(&frame->info, &ksig->info))
406 /* Set up registers for signal handler */
407 regs->sp = (unsigned long)frame;
408 regs->ip = (unsigned long)ksig->ka.sa.sa_handler;
409 regs->ax = (unsigned long)sig;
410 regs->dx = (unsigned long)&frame->info;
411 regs->cx = (unsigned long)&frame->uc;
413 regs->ds = __USER_DS;
414 regs->es = __USER_DS;
415 regs->ss = __USER_DS;
416 regs->cs = __USER_CS;
423 #else /* !CONFIG_X86_32 */
424 static unsigned long frame_uc_flags(struct pt_regs *regs)
428 if (boot_cpu_has(X86_FEATURE_XSAVE))
429 flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS;
431 flags = UC_SIGCONTEXT_SS;
433 if (likely(user_64bit_mode(regs)))
434 flags |= UC_STRICT_RESTORE_SS;
439 static int __setup_rt_frame(int sig, struct ksignal *ksig,
440 sigset_t *set, struct pt_regs *regs)
442 struct rt_sigframe __user *frame;
443 void __user *fp = NULL;
444 unsigned long uc_flags;
446 /* x86-64 should always use SA_RESTORER. */
447 if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
450 frame = get_sigframe(&ksig->ka, regs, sizeof(struct rt_sigframe), &fp);
451 uc_flags = frame_uc_flags(regs);
453 if (!user_access_begin(frame, sizeof(*frame)))
456 /* Create the ucontext. */
457 unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
458 unsafe_put_user(0, &frame->uc.uc_link, Efault);
459 unsafe_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
461 /* Set up to return from userspace. If provided, use a stub
462 already in userspace. */
463 unsafe_put_user(ksig->ka.sa.sa_restorer, &frame->pretcode, Efault);
464 unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
465 unsafe_put_sigmask(set, frame, Efault);
468 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
469 if (copy_siginfo_to_user(&frame->info, &ksig->info))
473 /* Set up registers for signal handler */
475 /* In case the signal handler was declared without prototypes */
478 /* This also works for non SA_SIGINFO handlers because they expect the
479 next argument after the signal number on the stack. */
480 regs->si = (unsigned long)&frame->info;
481 regs->dx = (unsigned long)&frame->uc;
482 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
484 regs->sp = (unsigned long)frame;
487 * Set up the CS and SS registers to run signal handlers in
488 * 64-bit mode, even if the handler happens to be interrupting
489 * 32-bit or 16-bit code.
491 * SS is subtle. In 64-bit mode, we don't need any particular
492 * SS descriptor, but we do need SS to be valid. It's possible
493 * that the old SS is entirely bogus -- this can happen if the
494 * signal we're trying to deliver is #GP or #SS caused by a bad
495 * SS value. We also have a compatbility issue here: DOSEMU
496 * relies on the contents of the SS register indicating the
497 * SS value at the time of the signal, even though that code in
498 * DOSEMU predates sigreturn's ability to restore SS. (DOSEMU
499 * avoids relying on sigreturn to restore SS; instead it uses
500 * a trampoline.) So we do our best: if the old SS was valid,
501 * we keep it. Otherwise we replace it.
503 regs->cs = __USER_CS;
505 if (unlikely(regs->ss != __USER_DS))
506 force_valid_ss(regs);
514 #endif /* CONFIG_X86_32 */
516 #ifdef CONFIG_X86_X32_ABI
517 static int x32_copy_siginfo_to_user(struct compat_siginfo __user *to,
518 const struct kernel_siginfo *from)
520 struct compat_siginfo new;
522 copy_siginfo_to_external32(&new, from);
523 if (from->si_signo == SIGCHLD) {
524 new._sifields._sigchld_x32._utime = from->si_utime;
525 new._sifields._sigchld_x32._stime = from->si_stime;
527 if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
532 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
533 const struct kernel_siginfo *from)
535 if (in_x32_syscall())
536 return x32_copy_siginfo_to_user(to, from);
537 return __copy_siginfo_to_user32(to, from);
539 #endif /* CONFIG_X86_X32_ABI */
541 static int x32_setup_rt_frame(struct ksignal *ksig,
542 compat_sigset_t *set,
543 struct pt_regs *regs)
545 #ifdef CONFIG_X86_X32_ABI
546 struct rt_sigframe_x32 __user *frame;
547 unsigned long uc_flags;
548 void __user *restorer;
549 void __user *fp = NULL;
551 if (!(ksig->ka.sa.sa_flags & SA_RESTORER))
554 frame = get_sigframe(&ksig->ka, regs, sizeof(*frame), &fp);
556 uc_flags = frame_uc_flags(regs);
558 if (!user_access_begin(frame, sizeof(*frame)))
561 /* Create the ucontext. */
562 unsafe_put_user(uc_flags, &frame->uc.uc_flags, Efault);
563 unsafe_put_user(0, &frame->uc.uc_link, Efault);
564 unsafe_compat_save_altstack(&frame->uc.uc_stack, regs->sp, Efault);
565 unsafe_put_user(0, &frame->uc.uc__pad0, Efault);
566 restorer = ksig->ka.sa.sa_restorer;
567 unsafe_put_user(restorer, (unsigned long __user *)&frame->pretcode, Efault);
568 unsafe_put_sigcontext(&frame->uc.uc_mcontext, fp, regs, set, Efault);
569 unsafe_put_sigmask(set, frame, Efault);
572 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
573 if (x32_copy_siginfo_to_user(&frame->info, &ksig->info))
577 /* Set up registers for signal handler */
578 regs->sp = (unsigned long) frame;
579 regs->ip = (unsigned long) ksig->ka.sa.sa_handler;
581 /* We use the x32 calling convention here... */
582 regs->di = ksig->sig;
583 regs->si = (unsigned long) &frame->info;
584 regs->dx = (unsigned long) &frame->uc;
586 loadsegment(ds, __USER_DS);
587 loadsegment(es, __USER_DS);
589 regs->cs = __USER_CS;
590 regs->ss = __USER_DS;
591 #endif /* CONFIG_X86_X32_ABI */
594 #ifdef CONFIG_X86_X32_ABI
602 * Do a signal return; undo the signal stack.
605 SYSCALL_DEFINE0(sigreturn)
607 struct pt_regs *regs = current_pt_regs();
608 struct sigframe __user *frame;
611 frame = (struct sigframe __user *)(regs->sp - 8);
613 if (!access_ok(frame, sizeof(*frame)))
615 if (__get_user(set.sig[0], &frame->sc.oldmask) ||
616 __get_user(set.sig[1], &frame->extramask[0]))
619 set_current_blocked(&set);
622 * x86_32 has no uc_flags bits relevant to restore_sigcontext.
623 * Save a few cycles by skipping the __get_user.
625 if (restore_sigcontext(regs, &frame->sc, 0))
630 signal_fault(regs, frame, "sigreturn");
634 #endif /* CONFIG_X86_32 */
636 SYSCALL_DEFINE0(rt_sigreturn)
638 struct pt_regs *regs = current_pt_regs();
639 struct rt_sigframe __user *frame;
641 unsigned long uc_flags;
643 frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
644 if (!access_ok(frame, sizeof(*frame)))
646 if (__get_user(*(__u64 *)&set, (__u64 __user *)&frame->uc.uc_sigmask))
648 if (__get_user(uc_flags, &frame->uc.uc_flags))
651 set_current_blocked(&set);
653 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
656 if (restore_altstack(&frame->uc.uc_stack))
662 signal_fault(regs, frame, "rt_sigreturn");
666 static inline int is_ia32_compat_frame(struct ksignal *ksig)
668 return IS_ENABLED(CONFIG_IA32_EMULATION) &&
669 ksig->ka.sa.sa_flags & SA_IA32_ABI;
672 static inline int is_ia32_frame(struct ksignal *ksig)
674 return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);
677 static inline int is_x32_frame(struct ksignal *ksig)
679 return IS_ENABLED(CONFIG_X86_X32_ABI) &&
680 ksig->ka.sa.sa_flags & SA_X32_ABI;
684 setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
686 int usig = ksig->sig;
687 sigset_t *set = sigmask_to_save();
688 compat_sigset_t *cset = (compat_sigset_t *) set;
690 /* Perform fixup for the pre-signal frame. */
691 rseq_signal_deliver(ksig, regs);
693 /* Set up the stack frame */
694 if (is_ia32_frame(ksig)) {
695 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
696 return ia32_setup_rt_frame(usig, ksig, cset, regs);
698 return ia32_setup_frame(usig, ksig, cset, regs);
699 } else if (is_x32_frame(ksig)) {
700 return x32_setup_rt_frame(ksig, cset, regs);
702 return __setup_rt_frame(ksig->sig, ksig, set, regs);
707 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
709 bool stepping, failed;
710 struct fpu *fpu = ¤t->thread.fpu;
712 if (v8086_mode(regs))
713 save_v86_state((struct kernel_vm86_regs *) regs, VM86_SIGNAL);
715 /* Are we from a system call? */
716 if (syscall_get_nr(current, regs) >= 0) {
717 /* If so, check system call restarting.. */
718 switch (syscall_get_error(current, regs)) {
719 case -ERESTART_RESTARTBLOCK:
720 case -ERESTARTNOHAND:
725 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
730 case -ERESTARTNOINTR:
731 regs->ax = regs->orig_ax;
738 * If TF is set due to a debugger (TIF_FORCED_TF), clear TF now
739 * so that register information in the sigcontext is correct and
740 * then notify the tracer before entering the signal handler.
742 stepping = test_thread_flag(TIF_SINGLESTEP);
744 user_disable_single_step(current);
746 failed = (setup_rt_frame(ksig, regs) < 0);
749 * Clear the direction flag as per the ABI for function entry.
751 * Clear RF when entering the signal handler, because
752 * it might disable possible debug exception from the
755 * Clear TF for the case when it wasn't set by debugger to
756 * avoid the recursive send_sigtrap() in SIGTRAP handler.
758 regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);
760 * Ensure the signal handler starts with the new fpu state.
762 fpu__clear_user_states(fpu);
764 signal_setup_done(failed, ksig, stepping);
767 static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
770 * This function is fundamentally broken as currently
773 * The idea is that we want to trigger a call to the
774 * restart_block() syscall and that we want in_ia32_syscall(),
775 * in_x32_syscall(), etc. to match whatever they were in the
776 * syscall being restarted. We assume that the syscall
777 * instruction at (regs->ip - 2) matches whatever syscall
778 * instruction we used to enter in the first place.
780 * The problem is that we can get here when ptrace pokes
781 * syscall-like values into regs even if we're not in a syscall
784 * For now, we maintain historical behavior and guess based on
785 * stored state. We could do better by saving the actual
786 * syscall arch in restart_block or (with caveats on x32) by
787 * checking if regs->ip points to 'int $0x80'. The current
788 * behavior is incorrect if a tracer has a different bitness
791 #ifdef CONFIG_IA32_EMULATION
792 if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED))
793 return __NR_ia32_restart_syscall;
795 #ifdef CONFIG_X86_X32_ABI
796 return __NR_restart_syscall | (regs->orig_ax & __X32_SYSCALL_BIT);
798 return __NR_restart_syscall;
803 * Note that 'init' is a special process: it doesn't get signals it doesn't
804 * want to handle. Thus you cannot kill init even with a SIGKILL even by
807 void arch_do_signal(struct pt_regs *regs)
811 if (get_signal(&ksig)) {
812 /* Whee! Actually deliver the signal. */
813 handle_signal(&ksig, regs);
817 /* Did we come from a system call? */
818 if (syscall_get_nr(current, regs) >= 0) {
819 /* Restart the system call - no handlers present */
820 switch (syscall_get_error(current, regs)) {
821 case -ERESTARTNOHAND:
823 case -ERESTARTNOINTR:
824 regs->ax = regs->orig_ax;
828 case -ERESTART_RESTARTBLOCK:
829 regs->ax = get_nr_restart_syscall(regs);
836 * If there's no signal to deliver, we just put the saved sigmask
839 restore_saved_sigmask();
842 void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
844 struct task_struct *me = current;
846 if (show_unhandled_signals && printk_ratelimit()) {
848 "%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
849 task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
850 me->comm, me->pid, where, frame,
851 regs->ip, regs->sp, regs->orig_ax);
852 print_vma_addr(KERN_CONT " in ", regs->ip);
859 #ifdef CONFIG_X86_X32_ABI
860 COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn)
862 struct pt_regs *regs = current_pt_regs();
863 struct rt_sigframe_x32 __user *frame;
865 unsigned long uc_flags;
867 frame = (struct rt_sigframe_x32 __user *)(regs->sp - 8);
869 if (!access_ok(frame, sizeof(*frame)))
871 if (__get_user(set.sig[0], (__u64 __user *)&frame->uc.uc_sigmask))
873 if (__get_user(uc_flags, &frame->uc.uc_flags))
876 set_current_blocked(&set);
878 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags))
881 if (compat_restore_altstack(&frame->uc.uc_stack))
887 signal_fault(regs, frame, "x32 rt_sigreturn");