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 | |
25 | extern const unsigned long sigreturn_codes[17]; |
26 | |
27 | static unsigned long signal_return_offset; |
28 | |
29 | #ifdef CONFIG_IWMMXT |
30 | |
31 | static 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 | |
62 | static 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 | |
102 | static 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 | |
118 | static 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 | |
140 | static 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(to: &set, from: &sf->uc.uc_sigmask, n: sizeof(set)); |
148 | if (err == 0) |
149 | set_current_blocked(&set); |
150 | |
151 | err |= __copy_from_user(to: &context, from: &sf->uc.uc_mcontext, n: 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 | |
187 | asmlinkage 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, sf: frame)) |
208 | goto badframe; |
209 | |
210 | return regs->ARM_r0; |
211 | |
212 | badframe: |
213 | force_sig(SIGSEGV); |
214 | return 0; |
215 | } |
216 | |
217 | asmlinkage 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, sf: &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 | |
245 | badframe: |
246 | force_sig(SIGSEGV); |
247 | return 0; |
248 | } |
249 | |
250 | static int |
251 | setup_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(to: &sf->uc.uc_mcontext, from: &context, n: sizeof(context)); |
283 | |
284 | err |= __copy_to_user(to: &sf->uc.uc_sigmask, from: set, n: 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 | |
300 | static inline void __user * |
301 | get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize) |
302 | { |
303 | unsigned long sp = sigsp(sp: 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 | |
320 | static int |
321 | setup_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 | |
409 | rc_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(start: (unsigned long)rc, |
429 | end: (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 | |
446 | static int |
447 | setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) |
448 | { |
449 | struct sigframe __user *frame = get_sigframe(ksig, regs, framesize: 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(sf: frame, regs, set); |
461 | if (err == 0) |
462 | err = setup_return(regs, ksig, rc: frame->retcode, frame); |
463 | |
464 | return err; |
465 | } |
466 | |
467 | static int |
468 | setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) |
469 | { |
470 | struct rt_sigframe __user *frame = get_sigframe(ksig, regs, framesize: sizeof(*frame)); |
471 | int err = 0; |
472 | |
473 | if (!frame) |
474 | return 1; |
475 | |
476 | err |= copy_siginfo_to_user(to: &frame->info, from: &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(sf: &frame->sig, regs, set); |
483 | if (err == 0) |
484 | err = setup_return(regs, ksig, rc: 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 | */ |
502 | static 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, set: oldset, regs); |
517 | else |
518 | ret = setup_frame(ksig, set: 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(failed: ret, ksig, stepping: 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 | */ |
537 | static 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: &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: &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 | |
601 | asmlinkage int |
602 | do_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 | |
640 | struct 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, order: 0); |
648 | |
649 | if (!page) |
650 | return NULL; |
651 | |
652 | addr = page_address(page); |
653 | |
654 | /* Poison the entire page */ |
655 | memset32(s: addr, v: __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(start: ptr, end: ptr + PAGE_SIZE); |
668 | |
669 | return page; |
670 | } |
671 | |
672 | #ifdef CONFIG_DEBUG_RSEQ |
673 | asmlinkage 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 | */ |
683 | static_assert(NSIGILL == 11); |
684 | static_assert(NSIGFPE == 15); |
685 | static_assert(NSIGSEGV == 10); |
686 | static_assert(NSIGBUS == 5); |
687 | static_assert(NSIGTRAP == 6); |
688 | static_assert(NSIGCHLD == 6); |
689 | static_assert(NSIGSYS == 2); |
690 | static_assert(sizeof(siginfo_t) == 128); |
691 | static_assert(__alignof__(siginfo_t) == 4); |
692 | static_assert(offsetof(siginfo_t, si_signo) == 0x00); |
693 | static_assert(offsetof(siginfo_t, si_errno) == 0x04); |
694 | static_assert(offsetof(siginfo_t, si_code) == 0x08); |
695 | static_assert(offsetof(siginfo_t, si_pid) == 0x0c); |
696 | static_assert(offsetof(siginfo_t, si_uid) == 0x10); |
697 | static_assert(offsetof(siginfo_t, si_tid) == 0x0c); |
698 | static_assert(offsetof(siginfo_t, si_overrun) == 0x10); |
699 | static_assert(offsetof(siginfo_t, si_status) == 0x14); |
700 | static_assert(offsetof(siginfo_t, si_utime) == 0x18); |
701 | static_assert(offsetof(siginfo_t, si_stime) == 0x1c); |
702 | static_assert(offsetof(siginfo_t, si_value) == 0x14); |
703 | static_assert(offsetof(siginfo_t, si_int) == 0x14); |
704 | static_assert(offsetof(siginfo_t, si_ptr) == 0x14); |
705 | static_assert(offsetof(siginfo_t, si_addr) == 0x0c); |
706 | static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x10); |
707 | static_assert(offsetof(siginfo_t, si_lower) == 0x14); |
708 | static_assert(offsetof(siginfo_t, si_upper) == 0x18); |
709 | static_assert(offsetof(siginfo_t, si_pkey) == 0x14); |
710 | static_assert(offsetof(siginfo_t, si_perf_data) == 0x10); |
711 | static_assert(offsetof(siginfo_t, si_perf_type) == 0x14); |
712 | static_assert(offsetof(siginfo_t, si_perf_flags) == 0x18); |
713 | static_assert(offsetof(siginfo_t, si_band) == 0x0c); |
714 | static_assert(offsetof(siginfo_t, si_fd) == 0x10); |
715 | static_assert(offsetof(siginfo_t, si_call_addr) == 0x0c); |
716 | static_assert(offsetof(siginfo_t, si_syscall) == 0x10); |
717 | static_assert(offsetof(siginfo_t, si_arch) == 0x14); |
718 | |