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