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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/signal.c
4 *
5 * Copyright (C) 1995-2009 Russell King
6 */
7#include <linux/errno.h>
8#include <linux/random.h>
9#include <linux/signal.h>
10#include <linux/personality.h>
11#include <linux/uaccess.h>
12#include <linux/resume_user_mode.h>
13#include <linux/uprobes.h>
14#include <linux/syscalls.h>
15
16#include <asm/elf.h>
17#include <asm/cacheflush.h>
18#include <asm/traps.h>
19#include <asm/unistd.h>
20#include <asm/vfp.h>
21#include <asm/syscalls.h>
22
23#include "signal.h"
24
25extern const unsigned long sigreturn_codes[17];
26
27static unsigned long signal_return_offset;
28
29#ifdef CONFIG_IWMMXT
30
31static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
32{
33 char kbuf[sizeof(*frame) + 8];
34 struct iwmmxt_sigframe *kframe;
35 int err = 0;
36
37 /* the iWMMXt context must be 64 bit aligned */
38 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
39
40 if (test_thread_flag(TIF_USING_IWMMXT)) {
41 kframe->magic = IWMMXT_MAGIC;
42 kframe->size = IWMMXT_STORAGE_SIZE;
43 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
44 } else {
45 /*
46 * For bug-compatibility with older kernels, some space
47 * has to be reserved for iWMMXt even if it's not used.
48 * Set the magic and size appropriately so that properly
49 * written userspace can skip it reliably:
50 */
51 *kframe = (struct iwmmxt_sigframe) {
52 .magic = DUMMY_MAGIC,
53 .size = IWMMXT_STORAGE_SIZE,
54 };
55 }
56
57 err = __copy_to_user(frame, kframe, sizeof(*kframe));
58
59 return err;
60}
61
62static int restore_iwmmxt_context(char __user **auxp)
63{
64 struct iwmmxt_sigframe __user *frame =
65 (struct iwmmxt_sigframe __user *)*auxp;
66 char kbuf[sizeof(*frame) + 8];
67 struct iwmmxt_sigframe *kframe;
68
69 /* the iWMMXt context must be 64 bit aligned */
70 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
71 if (__copy_from_user(kframe, frame, sizeof(*frame)))
72 return -1;
73
74 /*
75 * For non-iWMMXt threads: a single iwmmxt_sigframe-sized dummy
76 * block is discarded for compatibility with setup_sigframe() if
77 * present, but we don't mandate its presence. If some other
78 * magic is here, it's not for us:
79 */
80 if (!test_thread_flag(TIF_USING_IWMMXT) &&
81 kframe->magic != DUMMY_MAGIC)
82 return 0;
83
84 if (kframe->size != IWMMXT_STORAGE_SIZE)
85 return -1;
86
87 if (test_thread_flag(TIF_USING_IWMMXT)) {
88 if (kframe->magic != IWMMXT_MAGIC)
89 return -1;
90
91 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
92 }
93
94 *auxp += IWMMXT_STORAGE_SIZE;
95 return 0;
96}
97
98#endif
99
100#ifdef CONFIG_VFP
101
102static int preserve_vfp_context(struct vfp_sigframe __user *frame)
103{
104 struct vfp_sigframe kframe;
105 int err = 0;
106
107 memset(&kframe, 0, sizeof(kframe));
108 kframe.magic = VFP_MAGIC;
109 kframe.size = VFP_STORAGE_SIZE;
110
111 err = vfp_preserve_user_clear_hwstate(&kframe.ufp, &kframe.ufp_exc);
112 if (err)
113 return err;
114
115 return __copy_to_user(frame, &kframe, sizeof(kframe));
116}
117
118static int restore_vfp_context(char __user **auxp)
119{
120 struct vfp_sigframe frame;
121 int err;
122
123 err = __copy_from_user(&frame, *auxp, sizeof(frame));
124 if (err)
125 return err;
126
127 if (frame.magic != VFP_MAGIC || frame.size != VFP_STORAGE_SIZE)
128 return -EINVAL;
129
130 *auxp += sizeof(frame);
131 return vfp_restore_user_hwstate(&frame.ufp, &frame.ufp_exc);
132}
133
134#endif
135
136/*
137 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
138 */
139
140static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
141{
142 struct sigcontext context;
143 char __user *aux;
144 sigset_t set;
145 int err;
146
147 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
148 if (err == 0)
149 set_current_blocked(&set);
150
151 err |= __copy_from_user(&context, &sf->uc.uc_mcontext, sizeof(context));
152 if (err == 0) {
153 regs->ARM_r0 = context.arm_r0;
154 regs->ARM_r1 = context.arm_r1;
155 regs->ARM_r2 = context.arm_r2;
156 regs->ARM_r3 = context.arm_r3;
157 regs->ARM_r4 = context.arm_r4;
158 regs->ARM_r5 = context.arm_r5;
159 regs->ARM_r6 = context.arm_r6;
160 regs->ARM_r7 = context.arm_r7;
161 regs->ARM_r8 = context.arm_r8;
162 regs->ARM_r9 = context.arm_r9;
163 regs->ARM_r10 = context.arm_r10;
164 regs->ARM_fp = context.arm_fp;
165 regs->ARM_ip = context.arm_ip;
166 regs->ARM_sp = context.arm_sp;
167 regs->ARM_lr = context.arm_lr;
168 regs->ARM_pc = context.arm_pc;
169 regs->ARM_cpsr = context.arm_cpsr;
170 }
171
172 err |= !valid_user_regs(regs);
173
174 aux = (char __user *) sf->uc.uc_regspace;
175#ifdef CONFIG_IWMMXT
176 if (err == 0)
177 err |= restore_iwmmxt_context(&aux);
178#endif
179#ifdef CONFIG_VFP
180 if (err == 0)
181 err |= restore_vfp_context(&aux);
182#endif
183
184 return err;
185}
186
187asmlinkage int sys_sigreturn(struct pt_regs *regs)
188{
189 struct sigframe __user *frame;
190
191 /* Always make any pending restarted system calls return -EINTR */
192 current->restart_block.fn = do_no_restart_syscall;
193
194 /*
195 * Since we stacked the signal on a 64-bit boundary,
196 * then 'sp' should be word aligned here. If it's
197 * not, then the user is trying to mess with us.
198 */
199 if (regs->ARM_sp & 7)
200 goto badframe;
201
202 frame = (struct sigframe __user *)regs->ARM_sp;
203
204 if (!access_ok(frame, sizeof (*frame)))
205 goto badframe;
206
207 if (restore_sigframe(regs, frame))
208 goto badframe;
209
210 return regs->ARM_r0;
211
212badframe:
213 force_sig(SIGSEGV);
214 return 0;
215}
216
217asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
218{
219 struct rt_sigframe __user *frame;
220
221 /* Always make any pending restarted system calls return -EINTR */
222 current->restart_block.fn = do_no_restart_syscall;
223
224 /*
225 * Since we stacked the signal on a 64-bit boundary,
226 * then 'sp' should be word aligned here. If it's
227 * not, then the user is trying to mess with us.
228 */
229 if (regs->ARM_sp & 7)
230 goto badframe;
231
232 frame = (struct rt_sigframe __user *)regs->ARM_sp;
233
234 if (!access_ok(frame, sizeof (*frame)))
235 goto badframe;
236
237 if (restore_sigframe(regs, &frame->sig))
238 goto badframe;
239
240 if (restore_altstack(&frame->sig.uc.uc_stack))
241 goto badframe;
242
243 return regs->ARM_r0;
244
245badframe:
246 force_sig(SIGSEGV);
247 return 0;
248}
249
250static int
251setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
252{
253 struct aux_sigframe __user *aux;
254 struct sigcontext context;
255 int err = 0;
256
257 context = (struct sigcontext) {
258 .arm_r0 = regs->ARM_r0,
259 .arm_r1 = regs->ARM_r1,
260 .arm_r2 = regs->ARM_r2,
261 .arm_r3 = regs->ARM_r3,
262 .arm_r4 = regs->ARM_r4,
263 .arm_r5 = regs->ARM_r5,
264 .arm_r6 = regs->ARM_r6,
265 .arm_r7 = regs->ARM_r7,
266 .arm_r8 = regs->ARM_r8,
267 .arm_r9 = regs->ARM_r9,
268 .arm_r10 = regs->ARM_r10,
269 .arm_fp = regs->ARM_fp,
270 .arm_ip = regs->ARM_ip,
271 .arm_sp = regs->ARM_sp,
272 .arm_lr = regs->ARM_lr,
273 .arm_pc = regs->ARM_pc,
274 .arm_cpsr = regs->ARM_cpsr,
275
276 .trap_no = current->thread.trap_no,
277 .error_code = current->thread.error_code,
278 .fault_address = current->thread.address,
279 .oldmask = set->sig[0],
280 };
281
282 err |= __copy_to_user(&sf->uc.uc_mcontext, &context, sizeof(context));
283
284 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
285
286 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
287#ifdef CONFIG_IWMMXT
288 if (err == 0)
289 err |= preserve_iwmmxt_context(&aux->iwmmxt);
290#endif
291#ifdef CONFIG_VFP
292 if (err == 0)
293 err |= preserve_vfp_context(&aux->vfp);
294#endif
295 err |= __put_user(0, &aux->end_magic);
296
297 return err;
298}
299
300static inline void __user *
301get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
302{
303 unsigned long sp = sigsp(regs->ARM_sp, ksig);
304 void __user *frame;
305
306 /*
307 * ATPCS B01 mandates 8-byte alignment
308 */
309 frame = (void __user *)((sp - framesize) & ~7);
310
311 /*
312 * Check that we can actually write to the signal frame.
313 */
314 if (!access_ok(frame, framesize))
315 frame = NULL;
316
317 return frame;
318}
319
320static int
321setup_return(struct pt_regs *regs, struct ksignal *ksig,
322 unsigned long __user *rc, void __user *frame)
323{
324 unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
325 unsigned long handler_fdpic_GOT = 0;
326 unsigned long retcode;
327 unsigned int idx, thumb = 0;
328 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
329 bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&
330 (current->personality & FDPIC_FUNCPTRS);
331
332 if (fdpic) {
333 unsigned long __user *fdpic_func_desc =
334 (unsigned long __user *)handler;
335 if (__get_user(handler, &fdpic_func_desc[0]) ||
336 __get_user(handler_fdpic_GOT, &fdpic_func_desc[1]))
337 return 1;
338 }
339
340 cpsr |= PSR_ENDSTATE;
341
342 /*
343 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
344 */
345 if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
346 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
347
348#ifdef CONFIG_ARM_THUMB
349 if (elf_hwcap & HWCAP_THUMB) {
350 /*
351 * The LSB of the handler determines if we're going to
352 * be using THUMB or ARM mode for this signal handler.
353 */
354 thumb = handler & 1;
355
356 /*
357 * Clear the If-Then Thumb-2 execution state. ARM spec
358 * requires this to be all 000s in ARM mode. Snapdragon
359 * S4/Krait misbehaves on a Thumb=>ARM signal transition
360 * without this.
361 *
362 * We must do this whenever we are running on a Thumb-2
363 * capable CPU, which includes ARMv6T2. However, we elect
364 * to always do this to simplify the code; this field is
365 * marked UNK/SBZP for older architectures.
366 */
367 cpsr &= ~PSR_IT_MASK;
368
369 if (thumb) {
370 cpsr |= PSR_T_BIT;
371 } else
372 cpsr &= ~PSR_T_BIT;
373 }
374#endif
375
376 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
377 retcode = (unsigned long)ksig->ka.sa.sa_restorer;
378 if (fdpic) {
379 /*
380 * We need code to load the function descriptor.
381 * That code follows the standard sigreturn code
382 * (6 words), and is made of 3 + 2 words for each
383 * variant. The 4th copied word is the actual FD
384 * address that the assembly code expects.
385 */
386 idx = 6 + thumb * 3;
387 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
388 idx += 5;
389 if (__put_user(sigreturn_codes[idx], rc ) ||
390 __put_user(sigreturn_codes[idx+1], rc+1) ||
391 __put_user(sigreturn_codes[idx+2], rc+2) ||
392 __put_user(retcode, rc+3))
393 return 1;
394 goto rc_finish;
395 }
396 } else {
397 idx = thumb << 1;
398 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
399 idx += 3;
400
401 /*
402 * Put the sigreturn code on the stack no matter which return
403 * mechanism we use in order to remain ABI compliant
404 */
405 if (__put_user(sigreturn_codes[idx], rc) ||
406 __put_user(sigreturn_codes[idx+1], rc+1))
407 return 1;
408
409rc_finish:
410#ifdef CONFIG_MMU
411 if (cpsr & MODE32_BIT) {
412 struct mm_struct *mm = current->mm;
413
414 /*
415 * 32-bit code can use the signal return page
416 * except when the MPU has protected the vectors
417 * page from PL0
418 */
419 retcode = mm->context.sigpage + signal_return_offset +
420 (idx << 2) + thumb;
421 } else
422#endif
423 {
424 /*
425 * Ensure that the instruction cache sees
426 * the return code written onto the stack.
427 */
428 flush_icache_range((unsigned long)rc,
429 (unsigned long)(rc + 3));
430
431 retcode = ((unsigned long)rc) + thumb;
432 }
433 }
434
435 regs->ARM_r0 = ksig->sig;
436 regs->ARM_sp = (unsigned long)frame;
437 regs->ARM_lr = retcode;
438 regs->ARM_pc = handler;
439 if (fdpic)
440 regs->ARM_r9 = handler_fdpic_GOT;
441 regs->ARM_cpsr = cpsr;
442
443 return 0;
444}
445
446static int
447setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
448{
449 struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
450 int err = 0;
451
452 if (!frame)
453 return 1;
454
455 /*
456 * Set uc.uc_flags to a value which sc.trap_no would never have.
457 */
458 err = __put_user(0x5ac3c35a, &frame->uc.uc_flags);
459
460 err |= setup_sigframe(frame, regs, set);
461 if (err == 0)
462 err = setup_return(regs, ksig, frame->retcode, frame);
463
464 return err;
465}
466
467static int
468setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
469{
470 struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
471 int err = 0;
472
473 if (!frame)
474 return 1;
475
476 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
477
478 err |= __put_user(0, &frame->sig.uc.uc_flags);
479 err |= __put_user(NULL, &frame->sig.uc.uc_link);
480
481 err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
482 err |= setup_sigframe(&frame->sig, regs, set);
483 if (err == 0)
484 err = setup_return(regs, ksig, frame->sig.retcode, frame);
485
486 if (err == 0) {
487 /*
488 * For realtime signals we must also set the second and third
489 * arguments for the signal handler.
490 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
491 */
492 regs->ARM_r1 = (unsigned long)&frame->info;
493 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
494 }
495
496 return err;
497}
498
499/*
500 * OK, we're invoking a handler
501 */
502static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
503{
504 sigset_t *oldset = sigmask_to_save();
505 int ret;
506
507 /*
508 * Perform fixup for the pre-signal frame.
509 */
510 rseq_signal_deliver(ksig, regs);
511
512 /*
513 * Set up the stack frame
514 */
515 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
516 ret = setup_rt_frame(ksig, oldset, regs);
517 else
518 ret = setup_frame(ksig, oldset, regs);
519
520 /*
521 * Check that the resulting registers are actually sane.
522 */
523 ret |= !valid_user_regs(regs);
524
525 signal_setup_done(ret, ksig, 0);
526}
527
528/*
529 * Note that 'init' is a special process: it doesn't get signals it doesn't
530 * want to handle. Thus you cannot kill init even with a SIGKILL even by
531 * mistake.
532 *
533 * Note that we go through the signals twice: once to check the signals that
534 * the kernel can handle, and then we build all the user-level signal handling
535 * stack-frames in one go after that.
536 */
537static int do_signal(struct pt_regs *regs, int syscall)
538{
539 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
540 struct ksignal ksig;
541 int restart = 0;
542
543 /*
544 * If we were from a system call, check for system call restarting...
545 */
546 if (syscall) {
547 continue_addr = regs->ARM_pc;
548 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
549 retval = regs->ARM_r0;
550
551 /*
552 * Prepare for system call restart. We do this here so that a
553 * debugger will see the already changed PSW.
554 */
555 switch (retval) {
556 case -ERESTART_RESTARTBLOCK:
557 restart -= 2;
558 fallthrough;
559 case -ERESTARTNOHAND:
560 case -ERESTARTSYS:
561 case -ERESTARTNOINTR:
562 restart++;
563 regs->ARM_r0 = regs->ARM_ORIG_r0;
564 regs->ARM_pc = restart_addr;
565 break;
566 }
567 }
568
569 /*
570 * Get the signal to deliver. When running under ptrace, at this
571 * point the debugger may change all our registers ...
572 */
573 /*
574 * Depending on the signal settings we may need to revert the
575 * decision to restart the system call. But skip this if a
576 * debugger has chosen to restart at a different PC.
577 */
578 if (get_signal(&ksig)) {
579 /* handler */
580 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
581 if (retval == -ERESTARTNOHAND ||
582 retval == -ERESTART_RESTARTBLOCK
583 || (retval == -ERESTARTSYS
584 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
585 regs->ARM_r0 = -EINTR;
586 regs->ARM_pc = continue_addr;
587 }
588 }
589 handle_signal(&ksig, regs);
590 } else {
591 /* no handler */
592 restore_saved_sigmask();
593 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
594 regs->ARM_pc = continue_addr;
595 return restart;
596 }
597 }
598 return 0;
599}
600
601asmlinkage int
602do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
603{
604 /*
605 * The assembly code enters us with IRQs off, but it hasn't
606 * informed the tracing code of that for efficiency reasons.
607 * Update the trace code with the current status.
608 */
609 trace_hardirqs_off();
610 do {
611 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
612 schedule();
613 } else {
614 if (unlikely(!user_mode(regs)))
615 return 0;
616 local_irq_enable();
617 if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
618 int restart = do_signal(regs, syscall);
619 if (unlikely(restart)) {
620 /*
621 * Restart without handlers.
622 * Deal with it without leaving
623 * the kernel space.
624 */
625 return restart;
626 }
627 syscall = 0;
628 } else if (thread_flags & _TIF_UPROBE) {
629 uprobe_notify_resume(regs);
630 } else {
631 resume_user_mode_work(regs);
632 }
633 }
634 local_irq_disable();
635 thread_flags = read_thread_flags();
636 } while (thread_flags & _TIF_WORK_MASK);
637 return 0;
638}
639
640struct page *get_signal_page(void)
641{
642 unsigned long ptr;
643 unsigned offset;
644 struct page *page;
645 void *addr;
646
647 page = alloc_pages(GFP_KERNEL, 0);
648
649 if (!page)
650 return NULL;
651
652 addr = page_address(page);
653
654 /* Poison the entire page */
655 memset32(addr, __opcode_to_mem_arm(0xe7fddef1),
656 PAGE_SIZE / sizeof(u32));
657
658 /* Give the signal return code some randomness */
659 offset = 0x200 + (get_random_u16() & 0x7fc);
660 signal_return_offset = offset;
661
662 /* Copy signal return handlers into the page */
663 memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
664
665 /* Flush out all instructions in this page */
666 ptr = (unsigned long)addr;
667 flush_icache_range(ptr, ptr + PAGE_SIZE);
668
669 return page;
670}
671
672#ifdef CONFIG_DEBUG_RSEQ
673asmlinkage void do_rseq_syscall(struct pt_regs *regs)
674{
675 rseq_syscall(regs);
676}
677#endif
678
679/*
680 * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
681 * changes likely come with new fields that should be added below.
682 */
683static_assert(NSIGILL == 11);
684static_assert(NSIGFPE == 15);
685static_assert(NSIGSEGV == 10);
686static_assert(NSIGBUS == 5);
687static_assert(NSIGTRAP == 6);
688static_assert(NSIGCHLD == 6);
689static_assert(NSIGSYS == 2);
690static_assert(sizeof(siginfo_t) == 128);
691static_assert(__alignof__(siginfo_t) == 4);
692static_assert(offsetof(siginfo_t, si_signo) == 0x00);
693static_assert(offsetof(siginfo_t, si_errno) == 0x04);
694static_assert(offsetof(siginfo_t, si_code) == 0x08);
695static_assert(offsetof(siginfo_t, si_pid) == 0x0c);
696static_assert(offsetof(siginfo_t, si_uid) == 0x10);
697static_assert(offsetof(siginfo_t, si_tid) == 0x0c);
698static_assert(offsetof(siginfo_t, si_overrun) == 0x10);
699static_assert(offsetof(siginfo_t, si_status) == 0x14);
700static_assert(offsetof(siginfo_t, si_utime) == 0x18);
701static_assert(offsetof(siginfo_t, si_stime) == 0x1c);
702static_assert(offsetof(siginfo_t, si_value) == 0x14);
703static_assert(offsetof(siginfo_t, si_int) == 0x14);
704static_assert(offsetof(siginfo_t, si_ptr) == 0x14);
705static_assert(offsetof(siginfo_t, si_addr) == 0x0c);
706static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x10);
707static_assert(offsetof(siginfo_t, si_lower) == 0x14);
708static_assert(offsetof(siginfo_t, si_upper) == 0x18);
709static_assert(offsetof(siginfo_t, si_pkey) == 0x14);
710static_assert(offsetof(siginfo_t, si_perf_data) == 0x10);
711static_assert(offsetof(siginfo_t, si_perf_type) == 0x14);
712static_assert(offsetof(siginfo_t, si_perf_flags) == 0x18);
713static_assert(offsetof(siginfo_t, si_band) == 0x0c);
714static_assert(offsetof(siginfo_t, si_fd) == 0x10);
715static_assert(offsetof(siginfo_t, si_call_addr) == 0x0c);
716static_assert(offsetof(siginfo_t, si_syscall) == 0x10);
717static_assert(offsetof(siginfo_t, si_arch) == 0x14);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/signal.c
4 *
5 * Copyright (C) 1995-2009 Russell King
6 */
7#include <linux/errno.h>
8#include <linux/random.h>
9#include <linux/signal.h>
10#include <linux/personality.h>
11#include <linux/uaccess.h>
12#include <linux/resume_user_mode.h>
13#include <linux/uprobes.h>
14#include <linux/syscalls.h>
15
16#include <asm/elf.h>
17#include <asm/cacheflush.h>
18#include <asm/traps.h>
19#include <asm/unistd.h>
20#include <asm/vfp.h>
21
22#include "signal.h"
23
24extern const unsigned long sigreturn_codes[17];
25
26static unsigned long signal_return_offset;
27
28#ifdef CONFIG_IWMMXT
29
30static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
31{
32 char kbuf[sizeof(*frame) + 8];
33 struct iwmmxt_sigframe *kframe;
34 int err = 0;
35
36 /* the iWMMXt context must be 64 bit aligned */
37 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
38
39 if (test_thread_flag(TIF_USING_IWMMXT)) {
40 kframe->magic = IWMMXT_MAGIC;
41 kframe->size = IWMMXT_STORAGE_SIZE;
42 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
43 } else {
44 /*
45 * For bug-compatibility with older kernels, some space
46 * has to be reserved for iWMMXt even if it's not used.
47 * Set the magic and size appropriately so that properly
48 * written userspace can skip it reliably:
49 */
50 *kframe = (struct iwmmxt_sigframe) {
51 .magic = DUMMY_MAGIC,
52 .size = IWMMXT_STORAGE_SIZE,
53 };
54 }
55
56 err = __copy_to_user(frame, kframe, sizeof(*kframe));
57
58 return err;
59}
60
61static int restore_iwmmxt_context(char __user **auxp)
62{
63 struct iwmmxt_sigframe __user *frame =
64 (struct iwmmxt_sigframe __user *)*auxp;
65 char kbuf[sizeof(*frame) + 8];
66 struct iwmmxt_sigframe *kframe;
67
68 /* the iWMMXt context must be 64 bit aligned */
69 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
70 if (__copy_from_user(kframe, frame, sizeof(*frame)))
71 return -1;
72
73 /*
74 * For non-iWMMXt threads: a single iwmmxt_sigframe-sized dummy
75 * block is discarded for compatibility with setup_sigframe() if
76 * present, but we don't mandate its presence. If some other
77 * magic is here, it's not for us:
78 */
79 if (!test_thread_flag(TIF_USING_IWMMXT) &&
80 kframe->magic != DUMMY_MAGIC)
81 return 0;
82
83 if (kframe->size != IWMMXT_STORAGE_SIZE)
84 return -1;
85
86 if (test_thread_flag(TIF_USING_IWMMXT)) {
87 if (kframe->magic != IWMMXT_MAGIC)
88 return -1;
89
90 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
91 }
92
93 *auxp += IWMMXT_STORAGE_SIZE;
94 return 0;
95}
96
97#endif
98
99#ifdef CONFIG_VFP
100
101static int preserve_vfp_context(struct vfp_sigframe __user *frame)
102{
103 struct vfp_sigframe kframe;
104 int err = 0;
105
106 memset(&kframe, 0, sizeof(kframe));
107 kframe.magic = VFP_MAGIC;
108 kframe.size = VFP_STORAGE_SIZE;
109
110 err = vfp_preserve_user_clear_hwstate(&kframe.ufp, &kframe.ufp_exc);
111 if (err)
112 return err;
113
114 return __copy_to_user(frame, &kframe, sizeof(kframe));
115}
116
117static int restore_vfp_context(char __user **auxp)
118{
119 struct vfp_sigframe frame;
120 int err;
121
122 err = __copy_from_user(&frame, *auxp, sizeof(frame));
123 if (err)
124 return err;
125
126 if (frame.magic != VFP_MAGIC || frame.size != VFP_STORAGE_SIZE)
127 return -EINVAL;
128
129 *auxp += sizeof(frame);
130 return vfp_restore_user_hwstate(&frame.ufp, &frame.ufp_exc);
131}
132
133#endif
134
135/*
136 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
137 */
138
139static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
140{
141 struct sigcontext context;
142 char __user *aux;
143 sigset_t set;
144 int err;
145
146 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
147 if (err == 0)
148 set_current_blocked(&set);
149
150 err |= __copy_from_user(&context, &sf->uc.uc_mcontext, sizeof(context));
151 if (err == 0) {
152 regs->ARM_r0 = context.arm_r0;
153 regs->ARM_r1 = context.arm_r1;
154 regs->ARM_r2 = context.arm_r2;
155 regs->ARM_r3 = context.arm_r3;
156 regs->ARM_r4 = context.arm_r4;
157 regs->ARM_r5 = context.arm_r5;
158 regs->ARM_r6 = context.arm_r6;
159 regs->ARM_r7 = context.arm_r7;
160 regs->ARM_r8 = context.arm_r8;
161 regs->ARM_r9 = context.arm_r9;
162 regs->ARM_r10 = context.arm_r10;
163 regs->ARM_fp = context.arm_fp;
164 regs->ARM_ip = context.arm_ip;
165 regs->ARM_sp = context.arm_sp;
166 regs->ARM_lr = context.arm_lr;
167 regs->ARM_pc = context.arm_pc;
168 regs->ARM_cpsr = context.arm_cpsr;
169 }
170
171 err |= !valid_user_regs(regs);
172
173 aux = (char __user *) sf->uc.uc_regspace;
174#ifdef CONFIG_IWMMXT
175 if (err == 0)
176 err |= restore_iwmmxt_context(&aux);
177#endif
178#ifdef CONFIG_VFP
179 if (err == 0)
180 err |= restore_vfp_context(&aux);
181#endif
182
183 return err;
184}
185
186asmlinkage int sys_sigreturn(struct pt_regs *regs)
187{
188 struct sigframe __user *frame;
189
190 /* Always make any pending restarted system calls return -EINTR */
191 current->restart_block.fn = do_no_restart_syscall;
192
193 /*
194 * Since we stacked the signal on a 64-bit boundary,
195 * then 'sp' should be word aligned here. If it's
196 * not, then the user is trying to mess with us.
197 */
198 if (regs->ARM_sp & 7)
199 goto badframe;
200
201 frame = (struct sigframe __user *)regs->ARM_sp;
202
203 if (!access_ok(frame, sizeof (*frame)))
204 goto badframe;
205
206 if (restore_sigframe(regs, frame))
207 goto badframe;
208
209 return regs->ARM_r0;
210
211badframe:
212 force_sig(SIGSEGV);
213 return 0;
214}
215
216asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
217{
218 struct rt_sigframe __user *frame;
219
220 /* Always make any pending restarted system calls return -EINTR */
221 current->restart_block.fn = do_no_restart_syscall;
222
223 /*
224 * Since we stacked the signal on a 64-bit boundary,
225 * then 'sp' should be word aligned here. If it's
226 * not, then the user is trying to mess with us.
227 */
228 if (regs->ARM_sp & 7)
229 goto badframe;
230
231 frame = (struct rt_sigframe __user *)regs->ARM_sp;
232
233 if (!access_ok(frame, sizeof (*frame)))
234 goto badframe;
235
236 if (restore_sigframe(regs, &frame->sig))
237 goto badframe;
238
239 if (restore_altstack(&frame->sig.uc.uc_stack))
240 goto badframe;
241
242 return regs->ARM_r0;
243
244badframe:
245 force_sig(SIGSEGV);
246 return 0;
247}
248
249static int
250setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
251{
252 struct aux_sigframe __user *aux;
253 struct sigcontext context;
254 int err = 0;
255
256 context = (struct sigcontext) {
257 .arm_r0 = regs->ARM_r0,
258 .arm_r1 = regs->ARM_r1,
259 .arm_r2 = regs->ARM_r2,
260 .arm_r3 = regs->ARM_r3,
261 .arm_r4 = regs->ARM_r4,
262 .arm_r5 = regs->ARM_r5,
263 .arm_r6 = regs->ARM_r6,
264 .arm_r7 = regs->ARM_r7,
265 .arm_r8 = regs->ARM_r8,
266 .arm_r9 = regs->ARM_r9,
267 .arm_r10 = regs->ARM_r10,
268 .arm_fp = regs->ARM_fp,
269 .arm_ip = regs->ARM_ip,
270 .arm_sp = regs->ARM_sp,
271 .arm_lr = regs->ARM_lr,
272 .arm_pc = regs->ARM_pc,
273 .arm_cpsr = regs->ARM_cpsr,
274
275 .trap_no = current->thread.trap_no,
276 .error_code = current->thread.error_code,
277 .fault_address = current->thread.address,
278 .oldmask = set->sig[0],
279 };
280
281 err |= __copy_to_user(&sf->uc.uc_mcontext, &context, sizeof(context));
282
283 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
284
285 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
286#ifdef CONFIG_IWMMXT
287 if (err == 0)
288 err |= preserve_iwmmxt_context(&aux->iwmmxt);
289#endif
290#ifdef CONFIG_VFP
291 if (err == 0)
292 err |= preserve_vfp_context(&aux->vfp);
293#endif
294 err |= __put_user(0, &aux->end_magic);
295
296 return err;
297}
298
299static inline void __user *
300get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
301{
302 unsigned long sp = sigsp(regs->ARM_sp, ksig);
303 void __user *frame;
304
305 /*
306 * ATPCS B01 mandates 8-byte alignment
307 */
308 frame = (void __user *)((sp - framesize) & ~7);
309
310 /*
311 * Check that we can actually write to the signal frame.
312 */
313 if (!access_ok(frame, framesize))
314 frame = NULL;
315
316 return frame;
317}
318
319static int
320setup_return(struct pt_regs *regs, struct ksignal *ksig,
321 unsigned long __user *rc, void __user *frame)
322{
323 unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
324 unsigned long handler_fdpic_GOT = 0;
325 unsigned long retcode;
326 unsigned int idx, thumb = 0;
327 unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
328 bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&
329 (current->personality & FDPIC_FUNCPTRS);
330
331 if (fdpic) {
332 unsigned long __user *fdpic_func_desc =
333 (unsigned long __user *)handler;
334 if (__get_user(handler, &fdpic_func_desc[0]) ||
335 __get_user(handler_fdpic_GOT, &fdpic_func_desc[1]))
336 return 1;
337 }
338
339 cpsr |= PSR_ENDSTATE;
340
341 /*
342 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
343 */
344 if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
345 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
346
347#ifdef CONFIG_ARM_THUMB
348 if (elf_hwcap & HWCAP_THUMB) {
349 /*
350 * The LSB of the handler determines if we're going to
351 * be using THUMB or ARM mode for this signal handler.
352 */
353 thumb = handler & 1;
354
355 /*
356 * Clear the If-Then Thumb-2 execution state. ARM spec
357 * requires this to be all 000s in ARM mode. Snapdragon
358 * S4/Krait misbehaves on a Thumb=>ARM signal transition
359 * without this.
360 *
361 * We must do this whenever we are running on a Thumb-2
362 * capable CPU, which includes ARMv6T2. However, we elect
363 * to always do this to simplify the code; this field is
364 * marked UNK/SBZP for older architectures.
365 */
366 cpsr &= ~PSR_IT_MASK;
367
368 if (thumb) {
369 cpsr |= PSR_T_BIT;
370 } else
371 cpsr &= ~PSR_T_BIT;
372 }
373#endif
374
375 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
376 retcode = (unsigned long)ksig->ka.sa.sa_restorer;
377 if (fdpic) {
378 /*
379 * We need code to load the function descriptor.
380 * That code follows the standard sigreturn code
381 * (6 words), and is made of 3 + 2 words for each
382 * variant. The 4th copied word is the actual FD
383 * address that the assembly code expects.
384 */
385 idx = 6 + thumb * 3;
386 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
387 idx += 5;
388 if (__put_user(sigreturn_codes[idx], rc ) ||
389 __put_user(sigreturn_codes[idx+1], rc+1) ||
390 __put_user(sigreturn_codes[idx+2], rc+2) ||
391 __put_user(retcode, rc+3))
392 return 1;
393 goto rc_finish;
394 }
395 } else {
396 idx = thumb << 1;
397 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
398 idx += 3;
399
400 /*
401 * Put the sigreturn code on the stack no matter which return
402 * mechanism we use in order to remain ABI compliant
403 */
404 if (__put_user(sigreturn_codes[idx], rc) ||
405 __put_user(sigreturn_codes[idx+1], rc+1))
406 return 1;
407
408rc_finish:
409#ifdef CONFIG_MMU
410 if (cpsr & MODE32_BIT) {
411 struct mm_struct *mm = current->mm;
412
413 /*
414 * 32-bit code can use the signal return page
415 * except when the MPU has protected the vectors
416 * page from PL0
417 */
418 retcode = mm->context.sigpage + signal_return_offset +
419 (idx << 2) + thumb;
420 } else
421#endif
422 {
423 /*
424 * Ensure that the instruction cache sees
425 * the return code written onto the stack.
426 */
427 flush_icache_range((unsigned long)rc,
428 (unsigned long)(rc + 3));
429
430 retcode = ((unsigned long)rc) + thumb;
431 }
432 }
433
434 regs->ARM_r0 = ksig->sig;
435 regs->ARM_sp = (unsigned long)frame;
436 regs->ARM_lr = retcode;
437 regs->ARM_pc = handler;
438 if (fdpic)
439 regs->ARM_r9 = handler_fdpic_GOT;
440 regs->ARM_cpsr = cpsr;
441
442 return 0;
443}
444
445static int
446setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
447{
448 struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
449 int err = 0;
450
451 if (!frame)
452 return 1;
453
454 /*
455 * Set uc.uc_flags to a value which sc.trap_no would never have.
456 */
457 err = __put_user(0x5ac3c35a, &frame->uc.uc_flags);
458
459 err |= setup_sigframe(frame, regs, set);
460 if (err == 0)
461 err = setup_return(regs, ksig, frame->retcode, frame);
462
463 return err;
464}
465
466static int
467setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
468{
469 struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
470 int err = 0;
471
472 if (!frame)
473 return 1;
474
475 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
476
477 err |= __put_user(0, &frame->sig.uc.uc_flags);
478 err |= __put_user(NULL, &frame->sig.uc.uc_link);
479
480 err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
481 err |= setup_sigframe(&frame->sig, regs, set);
482 if (err == 0)
483 err = setup_return(regs, ksig, frame->sig.retcode, frame);
484
485 if (err == 0) {
486 /*
487 * For realtime signals we must also set the second and third
488 * arguments for the signal handler.
489 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
490 */
491 regs->ARM_r1 = (unsigned long)&frame->info;
492 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
493 }
494
495 return err;
496}
497
498/*
499 * OK, we're invoking a handler
500 */
501static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
502{
503 sigset_t *oldset = sigmask_to_save();
504 int ret;
505
506 /*
507 * Perform fixup for the pre-signal frame.
508 */
509 rseq_signal_deliver(ksig, regs);
510
511 /*
512 * Set up the stack frame
513 */
514 if (ksig->ka.sa.sa_flags & SA_SIGINFO)
515 ret = setup_rt_frame(ksig, oldset, regs);
516 else
517 ret = setup_frame(ksig, oldset, regs);
518
519 /*
520 * Check that the resulting registers are actually sane.
521 */
522 ret |= !valid_user_regs(regs);
523
524 signal_setup_done(ret, ksig, 0);
525}
526
527/*
528 * Note that 'init' is a special process: it doesn't get signals it doesn't
529 * want to handle. Thus you cannot kill init even with a SIGKILL even by
530 * mistake.
531 *
532 * Note that we go through the signals twice: once to check the signals that
533 * the kernel can handle, and then we build all the user-level signal handling
534 * stack-frames in one go after that.
535 */
536static int do_signal(struct pt_regs *regs, int syscall)
537{
538 unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
539 struct ksignal ksig;
540 int restart = 0;
541
542 /*
543 * If we were from a system call, check for system call restarting...
544 */
545 if (syscall) {
546 continue_addr = regs->ARM_pc;
547 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
548 retval = regs->ARM_r0;
549
550 /*
551 * Prepare for system call restart. We do this here so that a
552 * debugger will see the already changed PSW.
553 */
554 switch (retval) {
555 case -ERESTART_RESTARTBLOCK:
556 restart -= 2;
557 fallthrough;
558 case -ERESTARTNOHAND:
559 case -ERESTARTSYS:
560 case -ERESTARTNOINTR:
561 restart++;
562 regs->ARM_r0 = regs->ARM_ORIG_r0;
563 regs->ARM_pc = restart_addr;
564 break;
565 }
566 }
567
568 /*
569 * Get the signal to deliver. When running under ptrace, at this
570 * point the debugger may change all our registers ...
571 */
572 /*
573 * Depending on the signal settings we may need to revert the
574 * decision to restart the system call. But skip this if a
575 * debugger has chosen to restart at a different PC.
576 */
577 if (get_signal(&ksig)) {
578 /* handler */
579 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
580 if (retval == -ERESTARTNOHAND ||
581 retval == -ERESTART_RESTARTBLOCK
582 || (retval == -ERESTARTSYS
583 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
584 regs->ARM_r0 = -EINTR;
585 regs->ARM_pc = continue_addr;
586 }
587 }
588 handle_signal(&ksig, regs);
589 } else {
590 /* no handler */
591 restore_saved_sigmask();
592 if (unlikely(restart) && regs->ARM_pc == restart_addr) {
593 regs->ARM_pc = continue_addr;
594 return restart;
595 }
596 }
597 return 0;
598}
599
600asmlinkage int
601do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
602{
603 /*
604 * The assembly code enters us with IRQs off, but it hasn't
605 * informed the tracing code of that for efficiency reasons.
606 * Update the trace code with the current status.
607 */
608 trace_hardirqs_off();
609 do {
610 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
611 schedule();
612 } else {
613 if (unlikely(!user_mode(regs)))
614 return 0;
615 local_irq_enable();
616 if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
617 int restart = do_signal(regs, syscall);
618 if (unlikely(restart)) {
619 /*
620 * Restart without handlers.
621 * Deal with it without leaving
622 * the kernel space.
623 */
624 return restart;
625 }
626 syscall = 0;
627 } else if (thread_flags & _TIF_UPROBE) {
628 uprobe_notify_resume(regs);
629 } else {
630 resume_user_mode_work(regs);
631 }
632 }
633 local_irq_disable();
634 thread_flags = read_thread_flags();
635 } while (thread_flags & _TIF_WORK_MASK);
636 return 0;
637}
638
639struct page *get_signal_page(void)
640{
641 unsigned long ptr;
642 unsigned offset;
643 struct page *page;
644 void *addr;
645
646 page = alloc_pages(GFP_KERNEL, 0);
647
648 if (!page)
649 return NULL;
650
651 addr = page_address(page);
652
653 /* Poison the entire page */
654 memset32(addr, __opcode_to_mem_arm(0xe7fddef1),
655 PAGE_SIZE / sizeof(u32));
656
657 /* Give the signal return code some randomness */
658 offset = 0x200 + (get_random_u16() & 0x7fc);
659 signal_return_offset = offset;
660
661 /* Copy signal return handlers into the page */
662 memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
663
664 /* Flush out all instructions in this page */
665 ptr = (unsigned long)addr;
666 flush_icache_range(ptr, ptr + PAGE_SIZE);
667
668 return page;
669}
670
671#ifdef CONFIG_DEBUG_RSEQ
672asmlinkage void do_rseq_syscall(struct pt_regs *regs)
673{
674 rseq_syscall(regs);
675}
676#endif
677
678/*
679 * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
680 * changes likely come with new fields that should be added below.
681 */
682static_assert(NSIGILL == 11);
683static_assert(NSIGFPE == 15);
684static_assert(NSIGSEGV == 9);
685static_assert(NSIGBUS == 5);
686static_assert(NSIGTRAP == 6);
687static_assert(NSIGCHLD == 6);
688static_assert(NSIGSYS == 2);
689static_assert(sizeof(siginfo_t) == 128);
690static_assert(__alignof__(siginfo_t) == 4);
691static_assert(offsetof(siginfo_t, si_signo) == 0x00);
692static_assert(offsetof(siginfo_t, si_errno) == 0x04);
693static_assert(offsetof(siginfo_t, si_code) == 0x08);
694static_assert(offsetof(siginfo_t, si_pid) == 0x0c);
695static_assert(offsetof(siginfo_t, si_uid) == 0x10);
696static_assert(offsetof(siginfo_t, si_tid) == 0x0c);
697static_assert(offsetof(siginfo_t, si_overrun) == 0x10);
698static_assert(offsetof(siginfo_t, si_status) == 0x14);
699static_assert(offsetof(siginfo_t, si_utime) == 0x18);
700static_assert(offsetof(siginfo_t, si_stime) == 0x1c);
701static_assert(offsetof(siginfo_t, si_value) == 0x14);
702static_assert(offsetof(siginfo_t, si_int) == 0x14);
703static_assert(offsetof(siginfo_t, si_ptr) == 0x14);
704static_assert(offsetof(siginfo_t, si_addr) == 0x0c);
705static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x10);
706static_assert(offsetof(siginfo_t, si_lower) == 0x14);
707static_assert(offsetof(siginfo_t, si_upper) == 0x18);
708static_assert(offsetof(siginfo_t, si_pkey) == 0x14);
709static_assert(offsetof(siginfo_t, si_perf_data) == 0x10);
710static_assert(offsetof(siginfo_t, si_perf_type) == 0x14);
711static_assert(offsetof(siginfo_t, si_perf_flags) == 0x18);
712static_assert(offsetof(siginfo_t, si_band) == 0x0c);
713static_assert(offsetof(siginfo_t, si_fd) == 0x10);
714static_assert(offsetof(siginfo_t, si_call_addr) == 0x0c);
715static_assert(offsetof(siginfo_t, si_syscall) == 0x10);
716static_assert(offsetof(siginfo_t, si_arch) == 0x14);