1 // SPDX-License-Identifier: GPL-2.0-only
3 * Based on arch/arm/kernel/signal.c
5 * Copyright (C) 1995-2009 Russell King
6 * Copyright (C) 2012 ARM Ltd.
9 #include <linux/cache.h>
10 #include <linux/compat.h>
11 #include <linux/errno.h>
12 #include <linux/kernel.h>
13 #include <linux/signal.h>
14 #include <linux/personality.h>
15 #include <linux/freezer.h>
16 #include <linux/stddef.h>
17 #include <linux/uaccess.h>
18 #include <linux/sizes.h>
19 #include <linux/string.h>
20 #include <linux/tracehook.h>
21 #include <linux/ratelimit.h>
22 #include <linux/syscalls.h>
24 #include <asm/daifflags.h>
25 #include <asm/debug-monitors.h>
27 #include <asm/cacheflush.h>
28 #include <asm/ucontext.h>
29 #include <asm/unistd.h>
30 #include <asm/fpsimd.h>
31 #include <asm/ptrace.h>
32 #include <asm/syscall.h>
33 #include <asm/signal32.h>
34 #include <asm/traps.h>
38 * Do a signal return; undo the signal stack. These are aligned to 128-bit.
50 struct rt_sigframe_user_layout {
51 struct rt_sigframe __user *sigframe;
52 struct frame_record __user *next_frame;
54 unsigned long size; /* size of allocated sigframe data */
55 unsigned long limit; /* largest allowed size */
57 unsigned long fpsimd_offset;
58 unsigned long esr_offset;
59 unsigned long sve_offset;
60 unsigned long extra_offset;
61 unsigned long end_offset;
64 #define BASE_SIGFRAME_SIZE round_up(sizeof(struct rt_sigframe), 16)
65 #define TERMINATOR_SIZE round_up(sizeof(struct _aarch64_ctx), 16)
66 #define EXTRA_CONTEXT_SIZE round_up(sizeof(struct extra_context), 16)
68 static void init_user_layout(struct rt_sigframe_user_layout *user)
70 const size_t reserved_size =
71 sizeof(user->sigframe->uc.uc_mcontext.__reserved);
73 memset(user, 0, sizeof(*user));
74 user->size = offsetof(struct rt_sigframe, uc.uc_mcontext.__reserved);
76 user->limit = user->size + reserved_size;
78 user->limit -= TERMINATOR_SIZE;
79 user->limit -= EXTRA_CONTEXT_SIZE;
80 /* Reserve space for extension and terminator ^ */
83 static size_t sigframe_size(struct rt_sigframe_user_layout const *user)
85 return round_up(max(user->size, sizeof(struct rt_sigframe)), 16);
89 * Sanity limit on the approximate maximum size of signal frame we'll
90 * try to generate. Stack alignment padding and the frame record are
91 * not taken into account. This limit is not a guarantee and is
94 #define SIGFRAME_MAXSZ SZ_64K
96 static int __sigframe_alloc(struct rt_sigframe_user_layout *user,
97 unsigned long *offset, size_t size, bool extend)
99 size_t padded_size = round_up(size, 16);
101 if (padded_size > user->limit - user->size &&
102 !user->extra_offset &&
106 user->limit += EXTRA_CONTEXT_SIZE;
107 ret = __sigframe_alloc(user, &user->extra_offset,
108 sizeof(struct extra_context), false);
110 user->limit -= EXTRA_CONTEXT_SIZE;
114 /* Reserve space for the __reserved[] terminator */
115 user->size += TERMINATOR_SIZE;
118 * Allow expansion up to SIGFRAME_MAXSZ, ensuring space for
121 user->limit = SIGFRAME_MAXSZ - TERMINATOR_SIZE;
124 /* Still not enough space? Bad luck! */
125 if (padded_size > user->limit - user->size)
128 *offset = user->size;
129 user->size += padded_size;
135 * Allocate space for an optional record of <size> bytes in the user
136 * signal frame. The offset from the signal frame base address to the
137 * allocated block is assigned to *offset.
139 static int sigframe_alloc(struct rt_sigframe_user_layout *user,
140 unsigned long *offset, size_t size)
142 return __sigframe_alloc(user, offset, size, true);
145 /* Allocate the null terminator record and prevent further allocations */
146 static int sigframe_alloc_end(struct rt_sigframe_user_layout *user)
150 /* Un-reserve the space reserved for the terminator: */
151 user->limit += TERMINATOR_SIZE;
153 ret = sigframe_alloc(user, &user->end_offset,
154 sizeof(struct _aarch64_ctx));
158 /* Prevent further allocation: */
159 user->limit = user->size;
163 static void __user *apply_user_offset(
164 struct rt_sigframe_user_layout const *user, unsigned long offset)
166 char __user *base = (char __user *)user->sigframe;
168 return base + offset;
171 static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
173 struct user_fpsimd_state const *fpsimd =
174 ¤t->thread.uw.fpsimd_state;
177 /* copy the FP and status/control registers */
178 err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
179 __put_user_error(fpsimd->fpsr, &ctx->fpsr, err);
180 __put_user_error(fpsimd->fpcr, &ctx->fpcr, err);
182 /* copy the magic/size information */
183 __put_user_error(FPSIMD_MAGIC, &ctx->head.magic, err);
184 __put_user_error(sizeof(struct fpsimd_context), &ctx->head.size, err);
186 return err ? -EFAULT : 0;
189 static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
191 struct user_fpsimd_state fpsimd;
195 /* check the magic/size information */
196 __get_user_error(magic, &ctx->head.magic, err);
197 __get_user_error(size, &ctx->head.size, err);
200 if (magic != FPSIMD_MAGIC || size != sizeof(struct fpsimd_context))
203 /* copy the FP and status/control registers */
204 err = __copy_from_user(fpsimd.vregs, ctx->vregs,
205 sizeof(fpsimd.vregs));
206 __get_user_error(fpsimd.fpsr, &ctx->fpsr, err);
207 __get_user_error(fpsimd.fpcr, &ctx->fpcr, err);
209 clear_thread_flag(TIF_SVE);
211 /* load the hardware registers from the fpsimd_state structure */
213 fpsimd_update_current_state(&fpsimd);
215 return err ? -EFAULT : 0;
220 struct fpsimd_context __user *fpsimd;
221 struct sve_context __user *sve;
224 #ifdef CONFIG_ARM64_SVE
226 static int preserve_sve_context(struct sve_context __user *ctx)
229 u16 reserved[ARRAY_SIZE(ctx->__reserved)];
230 unsigned int vl = current->thread.sve_vl;
233 if (test_thread_flag(TIF_SVE))
234 vq = sve_vq_from_vl(vl);
236 memset(reserved, 0, sizeof(reserved));
238 __put_user_error(SVE_MAGIC, &ctx->head.magic, err);
239 __put_user_error(round_up(SVE_SIG_CONTEXT_SIZE(vq), 16),
240 &ctx->head.size, err);
241 __put_user_error(vl, &ctx->vl, err);
242 BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved));
243 err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved));
247 * This assumes that the SVE state has already been saved to
248 * the task struct by calling the function
249 * fpsimd_signal_preserve_current_state().
251 err |= __copy_to_user((char __user *)ctx + SVE_SIG_REGS_OFFSET,
252 current->thread.sve_state,
253 SVE_SIG_REGS_SIZE(vq));
256 return err ? -EFAULT : 0;
259 static int restore_sve_fpsimd_context(struct user_ctxs *user)
263 struct user_fpsimd_state fpsimd;
264 struct sve_context sve;
266 if (__copy_from_user(&sve, user->sve, sizeof(sve)))
269 if (sve.vl != current->thread.sve_vl)
272 if (sve.head.size <= sizeof(*user->sve)) {
273 clear_thread_flag(TIF_SVE);
277 vq = sve_vq_from_vl(sve.vl);
279 if (sve.head.size < SVE_SIG_CONTEXT_SIZE(vq))
283 * Careful: we are about __copy_from_user() directly into
284 * thread.sve_state with preemption enabled, so protection is
285 * needed to prevent a racing context switch from writing stale
286 * registers back over the new data.
289 fpsimd_flush_task_state(current);
290 /* From now, fpsimd_thread_switch() won't touch thread.sve_state */
293 err = __copy_from_user(current->thread.sve_state,
294 (char __user const *)user->sve +
296 SVE_SIG_REGS_SIZE(vq));
300 set_thread_flag(TIF_SVE);
303 /* copy the FP and status/control registers */
304 /* restore_sigframe() already checked that user->fpsimd != NULL. */
305 err = __copy_from_user(fpsimd.vregs, user->fpsimd->vregs,
306 sizeof(fpsimd.vregs));
307 __get_user_error(fpsimd.fpsr, &user->fpsimd->fpsr, err);
308 __get_user_error(fpsimd.fpcr, &user->fpsimd->fpcr, err);
310 /* load the hardware registers from the fpsimd_state structure */
312 fpsimd_update_current_state(&fpsimd);
314 return err ? -EFAULT : 0;
317 #else /* ! CONFIG_ARM64_SVE */
319 /* Turn any non-optimised out attempts to use these into a link error: */
320 extern int preserve_sve_context(void __user *ctx);
321 extern int restore_sve_fpsimd_context(struct user_ctxs *user);
323 #endif /* ! CONFIG_ARM64_SVE */
326 static int parse_user_sigframe(struct user_ctxs *user,
327 struct rt_sigframe __user *sf)
329 struct sigcontext __user *const sc = &sf->uc.uc_mcontext;
330 struct _aarch64_ctx __user *head;
331 char __user *base = (char __user *)&sc->__reserved;
333 size_t limit = sizeof(sc->__reserved);
334 bool have_extra_context = false;
335 char const __user *const sfp = (char const __user *)sf;
340 if (!IS_ALIGNED((unsigned long)base, 16))
346 char const __user *userp;
347 struct extra_context const __user *extra;
350 struct _aarch64_ctx const __user *end;
351 u32 end_magic, end_size;
353 if (limit - offset < sizeof(*head))
356 if (!IS_ALIGNED(offset, 16))
359 head = (struct _aarch64_ctx __user *)(base + offset);
360 __get_user_error(magic, &head->magic, err);
361 __get_user_error(size, &head->size, err);
365 if (limit - offset < size)
376 if (!system_supports_fpsimd())
381 if (size < sizeof(*user->fpsimd))
384 user->fpsimd = (struct fpsimd_context __user *)head;
392 if (!system_supports_sve())
398 if (size < sizeof(*user->sve))
401 user->sve = (struct sve_context __user *)head;
405 if (have_extra_context)
408 if (size < sizeof(*extra))
411 userp = (char const __user *)head;
413 extra = (struct extra_context const __user *)userp;
416 __get_user_error(extra_datap, &extra->datap, err);
417 __get_user_error(extra_size, &extra->size, err);
421 /* Check for the dummy terminator in __reserved[]: */
423 if (limit - offset - size < TERMINATOR_SIZE)
426 end = (struct _aarch64_ctx const __user *)userp;
427 userp += TERMINATOR_SIZE;
429 __get_user_error(end_magic, &end->magic, err);
430 __get_user_error(end_size, &end->size, err);
434 if (end_magic || end_size)
437 /* Prevent looping/repeated parsing of extra_context */
438 have_extra_context = true;
440 base = (__force void __user *)extra_datap;
441 if (!IS_ALIGNED((unsigned long)base, 16))
444 if (!IS_ALIGNED(extra_size, 16))
450 /* Reject "unreasonably large" frames: */
451 if (extra_size > sfp + SIGFRAME_MAXSZ - userp)
455 * Ignore trailing terminator in __reserved[]
456 * and start parsing extra data:
461 if (!access_ok(base, limit))
470 if (size < sizeof(*head))
473 if (limit - offset < size)
486 static int restore_sigframe(struct pt_regs *regs,
487 struct rt_sigframe __user *sf)
491 struct user_ctxs user;
493 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
495 set_current_blocked(&set);
497 for (i = 0; i < 31; i++)
498 __get_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
500 __get_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
501 __get_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
502 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
505 * Avoid sys_rt_sigreturn() restarting.
507 forget_syscall(regs);
509 err |= !valid_user_regs(®s->user_regs, current);
511 err = parse_user_sigframe(&user, sf);
513 if (err == 0 && system_supports_fpsimd()) {
518 if (!system_supports_sve())
521 err = restore_sve_fpsimd_context(&user);
523 err = restore_fpsimd_context(user.fpsimd);
530 SYSCALL_DEFINE0(rt_sigreturn)
532 struct pt_regs *regs = current_pt_regs();
533 struct rt_sigframe __user *frame;
535 /* Always make any pending restarted system calls return -EINTR */
536 current->restart_block.fn = do_no_restart_syscall;
539 * Since we stacked the signal on a 128-bit boundary, then 'sp' should
540 * be word aligned here.
545 frame = (struct rt_sigframe __user *)regs->sp;
547 if (!access_ok(frame, sizeof (*frame)))
550 if (restore_sigframe(regs, frame))
553 if (restore_altstack(&frame->uc.uc_stack))
556 return regs->regs[0];
559 arm64_notify_segfault(regs->sp);
564 * Determine the layout of optional records in the signal frame
566 * add_all: if true, lays out the biggest possible signal frame for
567 * this task; otherwise, generates a layout for the current state
570 static int setup_sigframe_layout(struct rt_sigframe_user_layout *user,
575 if (system_supports_fpsimd()) {
576 err = sigframe_alloc(user, &user->fpsimd_offset,
577 sizeof(struct fpsimd_context));
582 /* fault information, if valid */
583 if (add_all || current->thread.fault_code) {
584 err = sigframe_alloc(user, &user->esr_offset,
585 sizeof(struct esr_context));
590 if (system_supports_sve()) {
593 if (add_all || test_thread_flag(TIF_SVE)) {
597 vl = current->thread.sve_vl;
599 vq = sve_vq_from_vl(vl);
602 err = sigframe_alloc(user, &user->sve_offset,
603 SVE_SIG_CONTEXT_SIZE(vq));
608 return sigframe_alloc_end(user);
611 static int setup_sigframe(struct rt_sigframe_user_layout *user,
612 struct pt_regs *regs, sigset_t *set)
615 struct rt_sigframe __user *sf = user->sigframe;
617 /* set up the stack frame for unwinding */
618 __put_user_error(regs->regs[29], &user->next_frame->fp, err);
619 __put_user_error(regs->regs[30], &user->next_frame->lr, err);
621 for (i = 0; i < 31; i++)
622 __put_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
624 __put_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
625 __put_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
626 __put_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
628 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
630 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
632 if (err == 0 && system_supports_fpsimd()) {
633 struct fpsimd_context __user *fpsimd_ctx =
634 apply_user_offset(user, user->fpsimd_offset);
635 err |= preserve_fpsimd_context(fpsimd_ctx);
638 /* fault information, if valid */
639 if (err == 0 && user->esr_offset) {
640 struct esr_context __user *esr_ctx =
641 apply_user_offset(user, user->esr_offset);
643 __put_user_error(ESR_MAGIC, &esr_ctx->head.magic, err);
644 __put_user_error(sizeof(*esr_ctx), &esr_ctx->head.size, err);
645 __put_user_error(current->thread.fault_code, &esr_ctx->esr, err);
648 /* Scalable Vector Extension state, if present */
649 if (system_supports_sve() && err == 0 && user->sve_offset) {
650 struct sve_context __user *sve_ctx =
651 apply_user_offset(user, user->sve_offset);
652 err |= preserve_sve_context(sve_ctx);
655 if (err == 0 && user->extra_offset) {
656 char __user *sfp = (char __user *)user->sigframe;
658 apply_user_offset(user, user->extra_offset);
660 struct extra_context __user *extra;
661 struct _aarch64_ctx __user *end;
665 extra = (struct extra_context __user *)userp;
666 userp += EXTRA_CONTEXT_SIZE;
668 end = (struct _aarch64_ctx __user *)userp;
669 userp += TERMINATOR_SIZE;
672 * extra_datap is just written to the signal frame.
673 * The value gets cast back to a void __user *
676 extra_datap = (__force u64)userp;
677 extra_size = sfp + round_up(user->size, 16) - userp;
679 __put_user_error(EXTRA_MAGIC, &extra->head.magic, err);
680 __put_user_error(EXTRA_CONTEXT_SIZE, &extra->head.size, err);
681 __put_user_error(extra_datap, &extra->datap, err);
682 __put_user_error(extra_size, &extra->size, err);
684 /* Add the terminator */
685 __put_user_error(0, &end->magic, err);
686 __put_user_error(0, &end->size, err);
689 /* set the "end" magic */
691 struct _aarch64_ctx __user *end =
692 apply_user_offset(user, user->end_offset);
694 __put_user_error(0, &end->magic, err);
695 __put_user_error(0, &end->size, err);
701 static int get_sigframe(struct rt_sigframe_user_layout *user,
702 struct ksignal *ksig, struct pt_regs *regs)
704 unsigned long sp, sp_top;
707 init_user_layout(user);
708 err = setup_sigframe_layout(user, false);
712 sp = sp_top = sigsp(regs->sp, ksig);
714 sp = round_down(sp - sizeof(struct frame_record), 16);
715 user->next_frame = (struct frame_record __user *)sp;
717 sp = round_down(sp, 16) - sigframe_size(user);
718 user->sigframe = (struct rt_sigframe __user *)sp;
721 * Check that we can actually write to the signal frame.
723 if (!access_ok(user->sigframe, sp_top - sp))
729 static void setup_return(struct pt_regs *regs, struct k_sigaction *ka,
730 struct rt_sigframe_user_layout *user, int usig)
732 __sigrestore_t sigtramp;
734 regs->regs[0] = usig;
735 regs->sp = (unsigned long)user->sigframe;
736 regs->regs[29] = (unsigned long)&user->next_frame->fp;
737 regs->pc = (unsigned long)ka->sa.sa_handler;
740 * Signal delivery is a (wacky) indirect function call in
741 * userspace, so simulate the same setting of BTYPE as a BLR
742 * <register containing the signal handler entry point>.
743 * Signal delivery to a location in a PROT_BTI guarded page
744 * that is not a function entry point will now trigger a
745 * SIGILL in userspace.
747 * If the signal handler entry point is not in a PROT_BTI
748 * guarded page, this is harmless.
750 if (system_supports_bti()) {
751 regs->pstate &= ~PSR_BTYPE_MASK;
752 regs->pstate |= PSR_BTYPE_C;
755 /* TCO (Tag Check Override) always cleared for signal handlers */
756 regs->pstate &= ~PSR_TCO_BIT;
758 if (ka->sa.sa_flags & SA_RESTORER)
759 sigtramp = ka->sa.sa_restorer;
761 sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);
763 regs->regs[30] = (unsigned long)sigtramp;
766 static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
767 struct pt_regs *regs)
769 struct rt_sigframe_user_layout user;
770 struct rt_sigframe __user *frame;
773 fpsimd_signal_preserve_current_state();
775 if (get_sigframe(&user, ksig, regs))
778 frame = user.sigframe;
780 __put_user_error(0, &frame->uc.uc_flags, err);
781 __put_user_error(NULL, &frame->uc.uc_link, err);
783 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
784 err |= setup_sigframe(&user, regs, set);
786 setup_return(regs, &ksig->ka, &user, usig);
787 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
788 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
789 regs->regs[1] = (unsigned long)&frame->info;
790 regs->regs[2] = (unsigned long)&frame->uc;
797 static void setup_restart_syscall(struct pt_regs *regs)
799 if (is_compat_task())
800 compat_setup_restart_syscall(regs);
802 regs->regs[8] = __NR_restart_syscall;
806 * OK, we're invoking a handler
808 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
810 sigset_t *oldset = sigmask_to_save();
811 int usig = ksig->sig;
814 rseq_signal_deliver(ksig, regs);
817 * Set up the stack frame
819 if (is_compat_task()) {
820 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
821 ret = compat_setup_rt_frame(usig, ksig, oldset, regs);
823 ret = compat_setup_frame(usig, ksig, oldset, regs);
825 ret = setup_rt_frame(usig, ksig, oldset, regs);
829 * Check that the resulting registers are actually sane.
831 ret |= !valid_user_regs(®s->user_regs, current);
833 /* Step into the signal handler if we are stepping */
834 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
838 * Note that 'init' is a special process: it doesn't get signals it doesn't
839 * want to handle. Thus you cannot kill init even with a SIGKILL even by
842 * Note that we go through the signals twice: once to check the signals that
843 * the kernel can handle, and then we build all the user-level signal handling
844 * stack-frames in one go after that.
846 static void do_signal(struct pt_regs *regs)
848 unsigned long continue_addr = 0, restart_addr = 0;
851 bool syscall = in_syscall(regs);
854 * If we were from a system call, check for system call restarting...
857 continue_addr = regs->pc;
858 restart_addr = continue_addr - (compat_thumb_mode(regs) ? 2 : 4);
859 retval = regs->regs[0];
862 * Avoid additional syscall restarting via ret_to_user.
864 forget_syscall(regs);
867 * Prepare for system call restart. We do this here so that a
868 * debugger will see the already changed PC.
871 case -ERESTARTNOHAND:
873 case -ERESTARTNOINTR:
874 case -ERESTART_RESTARTBLOCK:
875 regs->regs[0] = regs->orig_x0;
876 regs->pc = restart_addr;
882 * Get the signal to deliver. When running under ptrace, at this point
883 * the debugger may change all of our registers.
885 if (get_signal(&ksig)) {
887 * Depending on the signal settings, we may need to revert the
888 * decision to restart the system call, but skip this if a
889 * debugger has chosen to restart at a different PC.
891 if (regs->pc == restart_addr &&
892 (retval == -ERESTARTNOHAND ||
893 retval == -ERESTART_RESTARTBLOCK ||
894 (retval == -ERESTARTSYS &&
895 !(ksig.ka.sa.sa_flags & SA_RESTART)))) {
896 syscall_set_return_value(current, regs, -EINTR, 0);
897 regs->pc = continue_addr;
900 handle_signal(&ksig, regs);
905 * Handle restarting a different system call. As above, if a debugger
906 * has chosen to restart at a different PC, ignore the restart.
908 if (syscall && regs->pc == restart_addr) {
909 if (retval == -ERESTART_RESTARTBLOCK)
910 setup_restart_syscall(regs);
911 user_rewind_single_step(current);
914 restore_saved_sigmask();
917 asmlinkage void do_notify_resume(struct pt_regs *regs,
918 unsigned long thread_flags)
921 /* Check valid user FS if needed */
922 addr_limit_user_check();
924 if (thread_flags & _TIF_NEED_RESCHED) {
925 /* Unmask Debug and SError for the next task */
926 local_daif_restore(DAIF_PROCCTX_NOIRQ);
930 local_daif_restore(DAIF_PROCCTX);
932 if (thread_flags & _TIF_UPROBE)
933 uprobe_notify_resume(regs);
935 if (thread_flags & _TIF_MTE_ASYNC_FAULT) {
936 clear_thread_flag(TIF_MTE_ASYNC_FAULT);
937 send_sig_fault(SIGSEGV, SEGV_MTEAERR,
938 (void __user *)NULL, current);
941 if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
944 if (thread_flags & _TIF_NOTIFY_RESUME) {
945 tracehook_notify_resume(regs);
946 rseq_handle_notify_resume(NULL, regs);
949 if (thread_flags & _TIF_FOREIGN_FPSTATE)
950 fpsimd_restore_current_state();
954 thread_flags = READ_ONCE(current_thread_info()->flags);
955 } while (thread_flags & _TIF_WORK_MASK);
958 unsigned long __ro_after_init signal_minsigstksz;
961 * Determine the stack space required for guaranteed signal devliery.
962 * This function is used to populate AT_MINSIGSTKSZ at process startup.
963 * cpufeatures setup is assumed to be complete.
965 void __init minsigstksz_setup(void)
967 struct rt_sigframe_user_layout user;
969 init_user_layout(&user);
972 * If this fails, SIGFRAME_MAXSZ needs to be enlarged. It won't
973 * be big enough, but it's our best guess:
975 if (WARN_ON(setup_sigframe_layout(&user, true)))
978 signal_minsigstksz = sigframe_size(&user) +
979 round_up(sizeof(struct frame_record), 16) +
980 16; /* max alignment padding */