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5
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/tracehook.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
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
46
47
48
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
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
75
76
77
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
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
191 current->restart_block.fn = do_no_restart_syscall;
192
193
194
195
196
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
221 current->restart_block.fn = do_no_restart_syscall;
222
223
224
225
226
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
307
308 frame = (void __user *)((sp - framesize) & ~7);
309
310
311
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
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
351
352
353 thumb = handler & 1;
354
355
356
357
358
359
360
361
362
363
364
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
380
381
382
383
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
402
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
415
416
417
418 retcode = mm->context.sigpage + signal_return_offset +
419 (idx << 2) + thumb;
420 } else
421#endif
422 {
423
424
425
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
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
488
489
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
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
508
509 rseq_signal_deliver(ksig, regs);
510
511
512
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
521
522 ret |= !valid_user_regs(regs);
523
524 signal_setup_done(ret, ksig, 0);
525}
526
527
528
529
530
531
532
533
534
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
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
552
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
570
571
572
573
574
575
576
577 if (get_signal(&ksig)) {
578
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
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
605
606
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
621
622
623
624 return restart;
625 }
626 syscall = 0;
627 } else if (thread_flags & _TIF_UPROBE) {
628 uprobe_notify_resume(regs);
629 } else {
630 tracehook_notify_resume(regs);
631 }
632 }
633 local_irq_disable();
634 thread_flags = current_thread_info()->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
654 memset32(addr, __opcode_to_mem_arm(0xe7fddef1),
655 PAGE_SIZE / sizeof(u32));
656
657
658 offset = 0x200 + (get_random_int() & 0x7fc);
659 signal_return_offset = offset;
660
661
662 memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
663
664
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
680
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_band) == 0x0c);
712static_assert(offsetof(siginfo_t, si_fd) == 0x10);
713static_assert(offsetof(siginfo_t, si_call_addr) == 0x0c);
714static_assert(offsetof(siginfo_t, si_syscall) == 0x10);
715static_assert(offsetof(siginfo_t, si_arch) == 0x14);
716