2 * Based on arch/arm/kernel/signal.c
4 * Copyright (C) 1995-2009 Russell King
5 * Copyright (C) 2012 ARM Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #include <linux/cache.h>
21 #include <linux/compat.h>
22 #include <linux/errno.h>
23 #include <linux/kernel.h>
24 #include <linux/signal.h>
25 #include <linux/personality.h>
26 #include <linux/freezer.h>
27 #include <linux/stddef.h>
28 #include <linux/uaccess.h>
29 #include <linux/sizes.h>
30 #include <linux/string.h>
31 #include <linux/tracehook.h>
32 #include <linux/ratelimit.h>
33 #include <linux/syscalls.h>
35 #include <asm/daifflags.h>
36 #include <asm/debug-monitors.h>
38 #include <asm/cacheflush.h>
39 #include <asm/ucontext.h>
40 #include <asm/unistd.h>
41 #include <asm/fpsimd.h>
42 #include <asm/ptrace.h>
43 #include <asm/signal32.h>
44 #include <asm/traps.h>
48 * Do a signal return; undo the signal stack. These are aligned to 128-bit.
60 struct rt_sigframe_user_layout {
61 struct rt_sigframe __user *sigframe;
62 struct frame_record __user *next_frame;
64 unsigned long size; /* size of allocated sigframe data */
65 unsigned long limit; /* largest allowed size */
67 unsigned long fpsimd_offset;
68 unsigned long esr_offset;
69 unsigned long sve_offset;
70 unsigned long extra_offset;
71 unsigned long end_offset;
74 #define BASE_SIGFRAME_SIZE round_up(sizeof(struct rt_sigframe), 16)
75 #define TERMINATOR_SIZE round_up(sizeof(struct _aarch64_ctx), 16)
76 #define EXTRA_CONTEXT_SIZE round_up(sizeof(struct extra_context), 16)
78 static void init_user_layout(struct rt_sigframe_user_layout *user)
80 const size_t reserved_size =
81 sizeof(user->sigframe->uc.uc_mcontext.__reserved);
83 memset(user, 0, sizeof(*user));
84 user->size = offsetof(struct rt_sigframe, uc.uc_mcontext.__reserved);
86 user->limit = user->size + reserved_size;
88 user->limit -= TERMINATOR_SIZE;
89 user->limit -= EXTRA_CONTEXT_SIZE;
90 /* Reserve space for extension and terminator ^ */
93 static size_t sigframe_size(struct rt_sigframe_user_layout const *user)
95 return round_up(max(user->size, sizeof(struct rt_sigframe)), 16);
99 * Sanity limit on the approximate maximum size of signal frame we'll
100 * try to generate. Stack alignment padding and the frame record are
101 * not taken into account. This limit is not a guarantee and is
104 #define SIGFRAME_MAXSZ SZ_64K
106 static int __sigframe_alloc(struct rt_sigframe_user_layout *user,
107 unsigned long *offset, size_t size, bool extend)
109 size_t padded_size = round_up(size, 16);
111 if (padded_size > user->limit - user->size &&
112 !user->extra_offset &&
116 user->limit += EXTRA_CONTEXT_SIZE;
117 ret = __sigframe_alloc(user, &user->extra_offset,
118 sizeof(struct extra_context), false);
120 user->limit -= EXTRA_CONTEXT_SIZE;
124 /* Reserve space for the __reserved[] terminator */
125 user->size += TERMINATOR_SIZE;
128 * Allow expansion up to SIGFRAME_MAXSZ, ensuring space for
131 user->limit = SIGFRAME_MAXSZ - TERMINATOR_SIZE;
134 /* Still not enough space? Bad luck! */
135 if (padded_size > user->limit - user->size)
138 *offset = user->size;
139 user->size += padded_size;
145 * Allocate space for an optional record of <size> bytes in the user
146 * signal frame. The offset from the signal frame base address to the
147 * allocated block is assigned to *offset.
149 static int sigframe_alloc(struct rt_sigframe_user_layout *user,
150 unsigned long *offset, size_t size)
152 return __sigframe_alloc(user, offset, size, true);
155 /* Allocate the null terminator record and prevent further allocations */
156 static int sigframe_alloc_end(struct rt_sigframe_user_layout *user)
160 /* Un-reserve the space reserved for the terminator: */
161 user->limit += TERMINATOR_SIZE;
163 ret = sigframe_alloc(user, &user->end_offset,
164 sizeof(struct _aarch64_ctx));
168 /* Prevent further allocation: */
169 user->limit = user->size;
173 static void __user *apply_user_offset(
174 struct rt_sigframe_user_layout const *user, unsigned long offset)
176 char __user *base = (char __user *)user->sigframe;
178 return base + offset;
181 static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
183 struct user_fpsimd_state const *fpsimd =
184 ¤t->thread.uw.fpsimd_state;
187 /* copy the FP and status/control registers */
188 err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
189 __put_user_error(fpsimd->fpsr, &ctx->fpsr, err);
190 __put_user_error(fpsimd->fpcr, &ctx->fpcr, err);
192 /* copy the magic/size information */
193 __put_user_error(FPSIMD_MAGIC, &ctx->head.magic, err);
194 __put_user_error(sizeof(struct fpsimd_context), &ctx->head.size, err);
196 return err ? -EFAULT : 0;
199 static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
201 struct user_fpsimd_state fpsimd;
205 /* check the magic/size information */
206 __get_user_error(magic, &ctx->head.magic, err);
207 __get_user_error(size, &ctx->head.size, err);
210 if (magic != FPSIMD_MAGIC || size != sizeof(struct fpsimd_context))
213 /* copy the FP and status/control registers */
214 err = __copy_from_user(fpsimd.vregs, ctx->vregs,
215 sizeof(fpsimd.vregs));
216 __get_user_error(fpsimd.fpsr, &ctx->fpsr, err);
217 __get_user_error(fpsimd.fpcr, &ctx->fpcr, err);
219 clear_thread_flag(TIF_SVE);
221 /* load the hardware registers from the fpsimd_state structure */
223 fpsimd_update_current_state(&fpsimd);
225 return err ? -EFAULT : 0;
230 struct fpsimd_context __user *fpsimd;
231 struct sve_context __user *sve;
234 #ifdef CONFIG_ARM64_SVE
236 static int preserve_sve_context(struct sve_context __user *ctx)
239 u16 reserved[ARRAY_SIZE(ctx->__reserved)];
240 unsigned int vl = current->thread.sve_vl;
243 if (test_thread_flag(TIF_SVE))
244 vq = sve_vq_from_vl(vl);
246 memset(reserved, 0, sizeof(reserved));
248 __put_user_error(SVE_MAGIC, &ctx->head.magic, err);
249 __put_user_error(round_up(SVE_SIG_CONTEXT_SIZE(vq), 16),
250 &ctx->head.size, err);
251 __put_user_error(vl, &ctx->vl, err);
252 BUILD_BUG_ON(sizeof(ctx->__reserved) != sizeof(reserved));
253 err |= __copy_to_user(&ctx->__reserved, reserved, sizeof(reserved));
257 * This assumes that the SVE state has already been saved to
258 * the task struct by calling preserve_fpsimd_context().
260 err |= __copy_to_user((char __user *)ctx + SVE_SIG_REGS_OFFSET,
261 current->thread.sve_state,
262 SVE_SIG_REGS_SIZE(vq));
265 return err ? -EFAULT : 0;
268 static int restore_sve_fpsimd_context(struct user_ctxs *user)
272 struct user_fpsimd_state fpsimd;
273 struct sve_context sve;
275 if (__copy_from_user(&sve, user->sve, sizeof(sve)))
278 if (sve.vl != current->thread.sve_vl)
281 if (sve.head.size <= sizeof(*user->sve)) {
282 clear_thread_flag(TIF_SVE);
286 vq = sve_vq_from_vl(sve.vl);
288 if (sve.head.size < SVE_SIG_CONTEXT_SIZE(vq))
292 * Careful: we are about __copy_from_user() directly into
293 * thread.sve_state with preemption enabled, so protection is
294 * needed to prevent a racing context switch from writing stale
295 * registers back over the new data.
298 fpsimd_flush_task_state(current);
300 /* From now, fpsimd_thread_switch() won't clear TIF_FOREIGN_FPSTATE */
302 set_thread_flag(TIF_FOREIGN_FPSTATE);
304 /* From now, fpsimd_thread_switch() won't touch thread.sve_state */
307 err = __copy_from_user(current->thread.sve_state,
308 (char __user const *)user->sve +
310 SVE_SIG_REGS_SIZE(vq));
314 set_thread_flag(TIF_SVE);
317 /* copy the FP and status/control registers */
318 /* restore_sigframe() already checked that user->fpsimd != NULL. */
319 err = __copy_from_user(fpsimd.vregs, user->fpsimd->vregs,
320 sizeof(fpsimd.vregs));
321 __get_user_error(fpsimd.fpsr, &user->fpsimd->fpsr, err);
322 __get_user_error(fpsimd.fpcr, &user->fpsimd->fpcr, err);
324 /* load the hardware registers from the fpsimd_state structure */
326 fpsimd_update_current_state(&fpsimd);
328 return err ? -EFAULT : 0;
331 #else /* ! CONFIG_ARM64_SVE */
333 /* Turn any non-optimised out attempts to use these into a link error: */
334 extern int preserve_sve_context(void __user *ctx);
335 extern int restore_sve_fpsimd_context(struct user_ctxs *user);
337 #endif /* ! CONFIG_ARM64_SVE */
340 static int parse_user_sigframe(struct user_ctxs *user,
341 struct rt_sigframe __user *sf)
343 struct sigcontext __user *const sc = &sf->uc.uc_mcontext;
344 struct _aarch64_ctx __user *head;
345 char __user *base = (char __user *)&sc->__reserved;
347 size_t limit = sizeof(sc->__reserved);
348 bool have_extra_context = false;
349 char const __user *const sfp = (char const __user *)sf;
354 if (!IS_ALIGNED((unsigned long)base, 16))
360 char const __user *userp;
361 struct extra_context const __user *extra;
364 struct _aarch64_ctx const __user *end;
365 u32 end_magic, end_size;
367 if (limit - offset < sizeof(*head))
370 if (!IS_ALIGNED(offset, 16))
373 head = (struct _aarch64_ctx __user *)(base + offset);
374 __get_user_error(magic, &head->magic, err);
375 __get_user_error(size, &head->size, err);
379 if (limit - offset < size)
393 if (size < sizeof(*user->fpsimd))
396 user->fpsimd = (struct fpsimd_context __user *)head;
404 if (!system_supports_sve())
410 if (size < sizeof(*user->sve))
413 user->sve = (struct sve_context __user *)head;
417 if (have_extra_context)
420 if (size < sizeof(*extra))
423 userp = (char const __user *)head;
425 extra = (struct extra_context const __user *)userp;
428 __get_user_error(extra_datap, &extra->datap, err);
429 __get_user_error(extra_size, &extra->size, err);
433 /* Check for the dummy terminator in __reserved[]: */
435 if (limit - offset - size < TERMINATOR_SIZE)
438 end = (struct _aarch64_ctx const __user *)userp;
439 userp += TERMINATOR_SIZE;
441 __get_user_error(end_magic, &end->magic, err);
442 __get_user_error(end_size, &end->size, err);
446 if (end_magic || end_size)
449 /* Prevent looping/repeated parsing of extra_context */
450 have_extra_context = true;
452 base = (__force void __user *)extra_datap;
453 if (!IS_ALIGNED((unsigned long)base, 16))
456 if (!IS_ALIGNED(extra_size, 16))
462 /* Reject "unreasonably large" frames: */
463 if (extra_size > sfp + SIGFRAME_MAXSZ - userp)
467 * Ignore trailing terminator in __reserved[]
468 * and start parsing extra data:
473 if (!access_ok(VERIFY_READ, base, limit))
482 if (size < sizeof(*head))
485 if (limit - offset < size)
498 static int restore_sigframe(struct pt_regs *regs,
499 struct rt_sigframe __user *sf)
503 struct user_ctxs user;
505 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
507 set_current_blocked(&set);
509 for (i = 0; i < 31; i++)
510 __get_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
512 __get_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
513 __get_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
514 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
517 * Avoid sys_rt_sigreturn() restarting.
519 forget_syscall(regs);
521 err |= !valid_user_regs(®s->user_regs, current);
523 err = parse_user_sigframe(&user, sf);
530 if (!system_supports_sve())
533 err = restore_sve_fpsimd_context(&user);
535 err = restore_fpsimd_context(user.fpsimd);
542 SYSCALL_DEFINE0(rt_sigreturn)
544 struct pt_regs *regs = current_pt_regs();
545 struct rt_sigframe __user *frame;
547 /* Always make any pending restarted system calls return -EINTR */
548 current->restart_block.fn = do_no_restart_syscall;
551 * Since we stacked the signal on a 128-bit boundary, then 'sp' should
552 * be word aligned here.
557 frame = (struct rt_sigframe __user *)regs->sp;
559 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
562 if (restore_sigframe(regs, frame))
565 if (restore_altstack(&frame->uc.uc_stack))
568 return regs->regs[0];
571 arm64_notify_segfault(regs->sp);
576 * Determine the layout of optional records in the signal frame
578 * add_all: if true, lays out the biggest possible signal frame for
579 * this task; otherwise, generates a layout for the current state
582 static int setup_sigframe_layout(struct rt_sigframe_user_layout *user,
587 err = sigframe_alloc(user, &user->fpsimd_offset,
588 sizeof(struct fpsimd_context));
592 /* fault information, if valid */
593 if (add_all || current->thread.fault_code) {
594 err = sigframe_alloc(user, &user->esr_offset,
595 sizeof(struct esr_context));
600 if (system_supports_sve()) {
603 if (add_all || test_thread_flag(TIF_SVE)) {
607 vl = current->thread.sve_vl;
609 vq = sve_vq_from_vl(vl);
612 err = sigframe_alloc(user, &user->sve_offset,
613 SVE_SIG_CONTEXT_SIZE(vq));
618 return sigframe_alloc_end(user);
621 static int setup_sigframe(struct rt_sigframe_user_layout *user,
622 struct pt_regs *regs, sigset_t *set)
625 struct rt_sigframe __user *sf = user->sigframe;
627 /* set up the stack frame for unwinding */
628 __put_user_error(regs->regs[29], &user->next_frame->fp, err);
629 __put_user_error(regs->regs[30], &user->next_frame->lr, err);
631 for (i = 0; i < 31; i++)
632 __put_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
634 __put_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
635 __put_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
636 __put_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
638 __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err);
640 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
643 struct fpsimd_context __user *fpsimd_ctx =
644 apply_user_offset(user, user->fpsimd_offset);
645 err |= preserve_fpsimd_context(fpsimd_ctx);
648 /* fault information, if valid */
649 if (err == 0 && user->esr_offset) {
650 struct esr_context __user *esr_ctx =
651 apply_user_offset(user, user->esr_offset);
653 __put_user_error(ESR_MAGIC, &esr_ctx->head.magic, err);
654 __put_user_error(sizeof(*esr_ctx), &esr_ctx->head.size, err);
655 __put_user_error(current->thread.fault_code, &esr_ctx->esr, err);
658 /* Scalable Vector Extension state, if present */
659 if (system_supports_sve() && err == 0 && user->sve_offset) {
660 struct sve_context __user *sve_ctx =
661 apply_user_offset(user, user->sve_offset);
662 err |= preserve_sve_context(sve_ctx);
665 if (err == 0 && user->extra_offset) {
666 char __user *sfp = (char __user *)user->sigframe;
668 apply_user_offset(user, user->extra_offset);
670 struct extra_context __user *extra;
671 struct _aarch64_ctx __user *end;
675 extra = (struct extra_context __user *)userp;
676 userp += EXTRA_CONTEXT_SIZE;
678 end = (struct _aarch64_ctx __user *)userp;
679 userp += TERMINATOR_SIZE;
682 * extra_datap is just written to the signal frame.
683 * The value gets cast back to a void __user *
686 extra_datap = (__force u64)userp;
687 extra_size = sfp + round_up(user->size, 16) - userp;
689 __put_user_error(EXTRA_MAGIC, &extra->head.magic, err);
690 __put_user_error(EXTRA_CONTEXT_SIZE, &extra->head.size, err);
691 __put_user_error(extra_datap, &extra->datap, err);
692 __put_user_error(extra_size, &extra->size, err);
694 /* Add the terminator */
695 __put_user_error(0, &end->magic, err);
696 __put_user_error(0, &end->size, err);
699 /* set the "end" magic */
701 struct _aarch64_ctx __user *end =
702 apply_user_offset(user, user->end_offset);
704 __put_user_error(0, &end->magic, err);
705 __put_user_error(0, &end->size, err);
711 static int get_sigframe(struct rt_sigframe_user_layout *user,
712 struct ksignal *ksig, struct pt_regs *regs)
714 unsigned long sp, sp_top;
717 init_user_layout(user);
718 err = setup_sigframe_layout(user, false);
722 sp = sp_top = sigsp(regs->sp, ksig);
724 sp = round_down(sp - sizeof(struct frame_record), 16);
725 user->next_frame = (struct frame_record __user *)sp;
727 sp = round_down(sp, 16) - sigframe_size(user);
728 user->sigframe = (struct rt_sigframe __user *)sp;
731 * Check that we can actually write to the signal frame.
733 if (!access_ok(VERIFY_WRITE, user->sigframe, sp_top - sp))
739 static void setup_return(struct pt_regs *regs, struct k_sigaction *ka,
740 struct rt_sigframe_user_layout *user, int usig)
742 __sigrestore_t sigtramp;
744 regs->regs[0] = usig;
745 regs->sp = (unsigned long)user->sigframe;
746 regs->regs[29] = (unsigned long)&user->next_frame->fp;
747 regs->pc = (unsigned long)ka->sa.sa_handler;
749 if (ka->sa.sa_flags & SA_RESTORER)
750 sigtramp = ka->sa.sa_restorer;
752 sigtramp = VDSO_SYMBOL(current->mm->context.vdso, sigtramp);
754 regs->regs[30] = (unsigned long)sigtramp;
757 static int setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
758 struct pt_regs *regs)
760 struct rt_sigframe_user_layout user;
761 struct rt_sigframe __user *frame;
764 fpsimd_signal_preserve_current_state();
766 if (get_sigframe(&user, ksig, regs))
769 frame = user.sigframe;
771 __put_user_error(0, &frame->uc.uc_flags, err);
772 __put_user_error(NULL, &frame->uc.uc_link, err);
774 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
775 err |= setup_sigframe(&user, regs, set);
777 setup_return(regs, &ksig->ka, &user, usig);
778 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
779 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
780 regs->regs[1] = (unsigned long)&frame->info;
781 regs->regs[2] = (unsigned long)&frame->uc;
788 static void setup_restart_syscall(struct pt_regs *regs)
790 if (is_compat_task())
791 compat_setup_restart_syscall(regs);
793 regs->regs[8] = __NR_restart_syscall;
797 * OK, we're invoking a handler
799 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
801 sigset_t *oldset = sigmask_to_save();
802 int usig = ksig->sig;
805 rseq_signal_deliver(ksig, regs);
808 * Set up the stack frame
810 if (is_compat_task()) {
811 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
812 ret = compat_setup_rt_frame(usig, ksig, oldset, regs);
814 ret = compat_setup_frame(usig, ksig, oldset, regs);
816 ret = setup_rt_frame(usig, ksig, oldset, regs);
820 * Check that the resulting registers are actually sane.
822 ret |= !valid_user_regs(®s->user_regs, current);
824 /* Step into the signal handler if we are stepping */
825 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
829 * Note that 'init' is a special process: it doesn't get signals it doesn't
830 * want to handle. Thus you cannot kill init even with a SIGKILL even by
833 * Note that we go through the signals twice: once to check the signals that
834 * the kernel can handle, and then we build all the user-level signal handling
835 * stack-frames in one go after that.
837 static void do_signal(struct pt_regs *regs)
839 unsigned long continue_addr = 0, restart_addr = 0;
842 bool syscall = in_syscall(regs);
845 * If we were from a system call, check for system call restarting...
848 continue_addr = regs->pc;
849 restart_addr = continue_addr - (compat_thumb_mode(regs) ? 2 : 4);
850 retval = regs->regs[0];
853 * Avoid additional syscall restarting via ret_to_user.
855 forget_syscall(regs);
858 * Prepare for system call restart. We do this here so that a
859 * debugger will see the already changed PC.
862 case -ERESTARTNOHAND:
864 case -ERESTARTNOINTR:
865 case -ERESTART_RESTARTBLOCK:
866 regs->regs[0] = regs->orig_x0;
867 regs->pc = restart_addr;
873 * Get the signal to deliver. When running under ptrace, at this point
874 * the debugger may change all of our registers.
876 if (get_signal(&ksig)) {
878 * Depending on the signal settings, we may need to revert the
879 * decision to restart the system call, but skip this if a
880 * debugger has chosen to restart at a different PC.
882 if (regs->pc == restart_addr &&
883 (retval == -ERESTARTNOHAND ||
884 retval == -ERESTART_RESTARTBLOCK ||
885 (retval == -ERESTARTSYS &&
886 !(ksig.ka.sa.sa_flags & SA_RESTART)))) {
887 regs->regs[0] = -EINTR;
888 regs->pc = continue_addr;
891 handle_signal(&ksig, regs);
896 * Handle restarting a different system call. As above, if a debugger
897 * has chosen to restart at a different PC, ignore the restart.
899 if (syscall && regs->pc == restart_addr) {
900 if (retval == -ERESTART_RESTARTBLOCK)
901 setup_restart_syscall(regs);
902 user_rewind_single_step(current);
905 restore_saved_sigmask();
908 asmlinkage void do_notify_resume(struct pt_regs *regs,
909 unsigned long thread_flags)
912 * The assembly code enters us with IRQs off, but it hasn't
913 * informed the tracing code of that for efficiency reasons.
914 * Update the trace code with the current status.
916 trace_hardirqs_off();
919 /* Check valid user FS if needed */
920 addr_limit_user_check();
922 if (thread_flags & _TIF_NEED_RESCHED) {
923 /* Unmask Debug and SError for the next task */
924 local_daif_restore(DAIF_PROCCTX_NOIRQ);
928 local_daif_restore(DAIF_PROCCTX);
930 if (thread_flags & _TIF_UPROBE)
931 uprobe_notify_resume(regs);
933 if (thread_flags & _TIF_SIGPENDING)
936 if (thread_flags & _TIF_NOTIFY_RESUME) {
937 clear_thread_flag(TIF_NOTIFY_RESUME);
938 tracehook_notify_resume(regs);
939 rseq_handle_notify_resume(NULL, regs);
942 if (thread_flags & _TIF_FOREIGN_FPSTATE)
943 fpsimd_restore_current_state();
947 thread_flags = READ_ONCE(current_thread_info()->flags);
948 } while (thread_flags & _TIF_WORK_MASK);
951 unsigned long __ro_after_init signal_minsigstksz;
954 * Determine the stack space required for guaranteed signal devliery.
955 * This function is used to populate AT_MINSIGSTKSZ at process startup.
956 * cpufeatures setup is assumed to be complete.
958 void __init minsigstksz_setup(void)
960 struct rt_sigframe_user_layout user;
962 init_user_layout(&user);
965 * If this fails, SIGFRAME_MAXSZ needs to be enlarged. It won't
966 * be big enough, but it's our best guess:
968 if (WARN_ON(setup_sigframe_layout(&user, true)))
971 signal_minsigstksz = sigframe_size(&user) +
972 round_up(sizeof(struct frame_record), 16) +
973 16; /* max alignment padding */