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Merge branch 'for-linus/samsung4' of git://git.fluff.org/bjdooks/linux
[linux-2.6-block.git] / arch / arm / kernel / signal.c
CommitLineData
1da177e4
LT		 1/*
2 * linux/arch/arm/kernel/signal.c
3 *
ab72b007 4 * Copyright (C) 1995-2009 Russell King
1da177e4
LT		 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 */
1da177e4
LT		 10#include <linux/errno.h>
11#include <linux/signal.h>
1da177e4 12#include <linux/personality.h>
7dfb7103 13#include <linux/freezer.h>
33fa9b13 14#include <linux/uaccess.h>
733e5e4b 15#include <linux/tracehook.h>
1da177e4 16
ee90dabc 17#include <asm/elf.h>
1da177e4
LT		 18#include <asm/cacheflush.h>
19#include <asm/ucontext.h>
1da177e4 20#include <asm/unistd.h>
82c6f5a5 21#include <asm/vfp.h>
1da177e4
LT		 22
23#include "ptrace.h"
e00d349e 24#include "signal.h"
1da177e4
LT		 25
26#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
27
28/*
29 * For ARM syscalls, we encode the syscall number into the instruction.
30 */
ee4cd588 31#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
32#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
ab72b007 33#define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
1da177e4 34
fcca538b
NP		 35/*
36 * With EABI, the syscall number has to be loaded into r7.
37 */
38#define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
39#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
40
1da177e4
LT		 41/*
42 * For Thumb syscalls, we pass the syscall number via r7. We therefore
43 * need two 16-bit instructions.
44 */
45#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
46#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
47
fcca538b
NP		 48const unsigned long sigreturn_codes[7] = {
49 MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
50 MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
1da177e4
LT		 51};
52
ab72b007
RK		 53/*
54 * Either we support OABI only, or we have EABI with the OABI
55 * compat layer enabled. In the later case we don't know if
56 * user space is EABI or not, and if not we must not clobber r7.
57 * Always using the OABI syscall solves that issue and works for
58 * all those cases.
59 */
60const unsigned long syscall_restart_code[2] = {
61 SWI_SYS_RESTART, /* swi __NR_restart_syscall */
62 0xe49df004, /* ldr pc, [sp], #4 */
63};
64
1da177e4
LT		 65/*
66 * atomically swap in the new signal mask, and wait for a signal.
67 */
36984265 68asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
1da177e4 69{
1da177e4
LT		 70 mask &= _BLOCKABLE;
71 spin_lock_irq(&current->sighand->siglock);
36984265 72 current->saved_sigmask = current->blocked;
1da177e4
LT		 73 siginitset(&current->blocked, mask);
74 recalc_sigpending();
75 spin_unlock_irq(&current->sighand->siglock);
1da177e4 76
36984265
MP		 77 current->state = TASK_INTERRUPTIBLE;
78 schedule();
79 set_restore_sigmask();
80 return -ERESTARTNOHAND;
1da177e4
LT		 81}
82
83asmlinkage int
84sys_sigaction(int sig, const struct old_sigaction __user *act,
85 struct old_sigaction __user *oact)
86{
87 struct k_sigaction new_ka, old_ka;
88 int ret;
89
90 if (act) {
91 old_sigset_t mask;
92 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
93 __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
94 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
95 return -EFAULT;
96 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
97 __get_user(mask, &act->sa_mask);
98 siginitset(&new_ka.sa.sa_mask, mask);
99 }
100
101 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
102
103 if (!ret && oact) {
104 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
105 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
106 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
107 return -EFAULT;
108 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
109 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
110 }
111
112 return ret;
113}
114
3bec6ded 115#ifdef CONFIG_CRUNCH
65a5053b 116static int preserve_crunch_context(struct crunch_sigframe __user *frame)
3bec6ded
LB		 117{
118 char kbuf[sizeof(*frame) + 8];
119 struct crunch_sigframe *kframe;
120
121 /* the crunch context must be 64 bit aligned */
122 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
123 kframe->magic = CRUNCH_MAGIC;
124 kframe->size = CRUNCH_STORAGE_SIZE;
125 crunch_task_copy(current_thread_info(), &kframe->storage);
126 return __copy_to_user(frame, kframe, sizeof(*frame));
127}
128
65a5053b 129static int restore_crunch_context(struct crunch_sigframe __user *frame)
3bec6ded
LB		 130{
131 char kbuf[sizeof(*frame) + 8];
132 struct crunch_sigframe *kframe;
133
134 /* the crunch context must be 64 bit aligned */
135 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
136 if (__copy_from_user(kframe, frame, sizeof(*frame)))
137 return -1;
138 if (kframe->magic != CRUNCH_MAGIC ||
139 kframe->size != CRUNCH_STORAGE_SIZE)
140 return -1;
141 crunch_task_restore(current_thread_info(), &kframe->storage);
142 return 0;
143}
144#endif
145
1da177e4
LT		 146#ifdef CONFIG_IWMMXT
147
1da177e4
LT		 148static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
149{
69b04754
HD		 150 char kbuf[sizeof(*frame) + 8];
151 struct iwmmxt_sigframe *kframe;
1da177e4
LT		 152
153 /* the iWMMXt context must be 64 bit aligned */
69b04754 154 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
85fe0681
DJ		 155 kframe->magic = IWMMXT_MAGIC;
156 kframe->size = IWMMXT_STORAGE_SIZE;
69b04754
HD		 157 iwmmxt_task_copy(current_thread_info(), &kframe->storage);
158 return __copy_to_user(frame, kframe, sizeof(*frame));
1da177e4
LT		 159}
160
161static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
162{
69b04754
HD		 163 char kbuf[sizeof(*frame) + 8];
164 struct iwmmxt_sigframe *kframe;
165
166 /* the iWMMXt context must be 64 bit aligned */
167 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
168 if (__copy_from_user(kframe, frame, sizeof(*frame)))
169 return -1;
85fe0681
DJ		 170 if (kframe->magic != IWMMXT_MAGIC ||
171 kframe->size != IWMMXT_STORAGE_SIZE)
69b04754
HD		 172 return -1;
173 iwmmxt_task_restore(current_thread_info(), &kframe->storage);
174 return 0;
1da177e4
LT		 175}
176
177#endif
178
82c6f5a5
ID		 179#ifdef CONFIG_VFP
180
181static int preserve_vfp_context(struct vfp_sigframe __user *frame)
182{
183 struct thread_info *thread = current_thread_info();
184 struct vfp_hard_struct *h = &thread->vfpstate.hard;
185 const unsigned long magic = VFP_MAGIC;
186 const unsigned long size = VFP_STORAGE_SIZE;
187 int err = 0;
188
189 vfp_sync_hwstate(thread);
190 __put_user_error(magic, &frame->magic, err);
191 __put_user_error(size, &frame->size, err);
192
193 /*
194 * Copy the floating point registers. There can be unused
195 * registers see asm/hwcap.h for details.
196 */
197 err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs,
198 sizeof(h->fpregs));
199 /*
200 * Copy the status and control register.
201 */
202 __put_user_error(h->fpscr, &frame->ufp.fpscr, err);
203
204 /*
205 * Copy the exception registers.
206 */
207 __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err);
208 __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
209 __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
210
211 return err ? -EFAULT : 0;
212}
213
214static int restore_vfp_context(struct vfp_sigframe __user *frame)
215{
216 struct thread_info *thread = current_thread_info();
217 struct vfp_hard_struct *h = &thread->vfpstate.hard;
218 unsigned long magic;
219 unsigned long size;
220 unsigned long fpexc;
221 int err = 0;
222
223 __get_user_error(magic, &frame->magic, err);
224 __get_user_error(size, &frame->size, err);
225
226 if (err)
227 return -EFAULT;
228 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
229 return -EINVAL;
230
231 /*
232 * Copy the floating point registers. There can be unused
233 * registers see asm/hwcap.h for details.
234 */
235 err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs,
236 sizeof(h->fpregs));
237 /*
238 * Copy the status and control register.
239 */
240 __get_user_error(h->fpscr, &frame->ufp.fpscr, err);
241
242 /*
243 * Sanitise and restore the exception registers.
244 */
245 __get_user_error(fpexc, &frame->ufp_exc.fpexc, err);
246 /* Ensure the VFP is enabled. */
247 fpexc |= FPEXC_EN;
248 /* Ensure FPINST2 is invalid and the exception flag is cleared. */
249 fpexc &= ~(FPEXC_EX | FPEXC_FP2V);
250 h->fpexc = fpexc;
251
252 __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
253 __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
254
255 if (!err)
256 vfp_flush_hwstate(thread);
257
258 return err ? -EFAULT : 0;
259}
260
261#endif
262
1da177e4
LT		 263/*
264 * Do a signal return; undo the signal stack. These are aligned to 64-bit.
265 */
266struct sigframe {
7d4fdc19 267 struct ucontext uc;
fcca538b 268 unsigned long retcode[2];
1da177e4
LT		 269};
270
271struct rt_sigframe {
1da177e4 272 struct siginfo info;
cb3504e8 273 struct sigframe sig;
1da177e4
LT		 274};
275
68071484 276static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
1da177e4 277{
85fe0681 278 struct aux_sigframe __user *aux;
68071484
RK		 279 sigset_t set;
280 int err;
281
282 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
283 if (err == 0) {
284 sigdelsetmask(&set, ~_BLOCKABLE);
285 spin_lock_irq(&current->sighand->siglock);
286 current->blocked = set;
287 recalc_sigpending();
288 spin_unlock_irq(&current->sighand->siglock);
289 }
1da177e4 290
68071484
RK		 291 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
292 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
293 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
294 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
295 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
296 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
297 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
298 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
299 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
300 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
301 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
302 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
303 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
304 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
305 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
306 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
307 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
1da177e4
LT		 308
309 err |= !valid_user_regs(regs);
310
85fe0681 311 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
3bec6ded
LB		 312#ifdef CONFIG_CRUNCH
313 if (err == 0)
314 err |= restore_crunch_context(&aux->crunch);
315#endif
1da177e4
LT		 316#ifdef CONFIG_IWMMXT
317 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
318 err |= restore_iwmmxt_context(&aux->iwmmxt);
319#endif
320#ifdef CONFIG_VFP
82c6f5a5
ID		 321 if (err == 0)
322 err |= restore_vfp_context(&aux->vfp);
1da177e4
LT		 323#endif
324
325 return err;
326}
327
328asmlinkage int sys_sigreturn(struct pt_regs *regs)
329{
330 struct sigframe __user *frame;
1da177e4
LT		 331
332 /* Always make any pending restarted system calls return -EINTR */
333 current_thread_info()->restart_block.fn = do_no_restart_syscall;
334
335 /*
336 * Since we stacked the signal on a 64-bit boundary,
337 * then 'sp' should be word aligned here. If it's
338 * not, then the user is trying to mess with us.
339 */
340 if (regs->ARM_sp & 7)
341 goto badframe;
342
343 frame = (struct sigframe __user *)regs->ARM_sp;
344
345 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
346 goto badframe;
1da177e4 347
68071484 348 if (restore_sigframe(regs, frame))
1da177e4
LT		 349 goto badframe;
350
b2a0d36f 351 single_step_trap(current);
1da177e4
LT		 352
353 return regs->ARM_r0;
354
355badframe:
356 force_sig(SIGSEGV, current);
357 return 0;
358}
359
360asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
361{
362 struct rt_sigframe __user *frame;
1da177e4
LT		 363
364 /* Always make any pending restarted system calls return -EINTR */
365 current_thread_info()->restart_block.fn = do_no_restart_syscall;
366
367 /*
368 * Since we stacked the signal on a 64-bit boundary,
369 * then 'sp' should be word aligned here. If it's
370 * not, then the user is trying to mess with us.
371 */
372 if (regs->ARM_sp & 7)
373 goto badframe;
374
375 frame = (struct rt_sigframe __user *)regs->ARM_sp;
376
377 if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
378 goto badframe;
1da177e4 379
68071484 380 if (restore_sigframe(regs, &frame->sig))
1da177e4
LT		 381 goto badframe;
382
cb3504e8 383 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
1da177e4
LT		 384 goto badframe;
385
b2a0d36f 386 single_step_trap(current);
1da177e4
LT		 387
388 return regs->ARM_r0;
389
390badframe:
391 force_sig(SIGSEGV, current);
392 return 0;
393}
394
395static int
aca6ca10 396setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
1da177e4 397{
85fe0681 398 struct aux_sigframe __user *aux;
1da177e4
LT		 399 int err = 0;
400
aca6ca10
RK		 401 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
402 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
403 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
404 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
405 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
406 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
407 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
408 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
409 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
410 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
411 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
412 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
413 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
414 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
415 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
416 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
417 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
418
419 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
420 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
421 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
422 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
423
424 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
1da177e4 425
85fe0681 426 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
3bec6ded
LB		 427#ifdef CONFIG_CRUNCH
428 if (err == 0)
429 err |= preserve_crunch_context(&aux->crunch);
430#endif
1da177e4
LT		 431#ifdef CONFIG_IWMMXT
432 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
433 err |= preserve_iwmmxt_context(&aux->iwmmxt);
434#endif
435#ifdef CONFIG_VFP
82c6f5a5
ID		 436 if (err == 0)
437 err |= preserve_vfp_context(&aux->vfp);
1da177e4 438#endif
85fe0681 439 __put_user_error(0, &aux->end_magic, err);
1da177e4
LT		 440
441 return err;
442}
443
444static inline void __user *
445get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
446{
447 unsigned long sp = regs->ARM_sp;
448 void __user *frame;
449
450 /*
451 * This is the X/Open sanctioned signal stack switching.
452 */
453 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
454 sp = current->sas_ss_sp + current->sas_ss_size;
455
456 /*
457 * ATPCS B01 mandates 8-byte alignment
458 */
459 frame = (void __user *)((sp - framesize) & ~7);
460
461 /*
462 * Check that we can actually write to the signal frame.
463 */
464 if (!access_ok(VERIFY_WRITE, frame, framesize))
465 frame = NULL;
466
467 return frame;
468}
469
470static int
471setup_return(struct pt_regs *regs, struct k_sigaction *ka,
472 unsigned long __user *rc, void __user *frame, int usig)
473{
474 unsigned long handler = (unsigned long)ka->sa.sa_handler;
475 unsigned long retcode;
476 int thumb = 0;
477 unsigned long cpsr = regs->ARM_cpsr & ~PSR_f;
478
479 /*
480 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
481 */
482 if (ka->sa.sa_flags & SA_THIRTYTWO)
483 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
484
485#ifdef CONFIG_ARM_THUMB
486 if (elf_hwcap & HWCAP_THUMB) {
487 /*
488 * The LSB of the handler determines if we're going to
489 * be using THUMB or ARM mode for this signal handler.
490 */
491 thumb = handler & 1;
492
d71e1352 493 if (thumb) {
1da177e4 494 cpsr |= PSR_T_BIT;
d71e1352
CM		 495#if __LINUX_ARM_ARCH__ >= 7
496 /* clear the If-Then Thumb-2 execution state */
497 cpsr &= ~PSR_IT_MASK;
498#endif
499 } else
1da177e4
LT		 500 cpsr &= ~PSR_T_BIT;
501 }
502#endif
503
504 if (ka->sa.sa_flags & SA_RESTORER) {
505 retcode = (unsigned long)ka->sa.sa_restorer;
506 } else {
fcca538b 507 unsigned int idx = thumb << 1;
1da177e4
LT		 508
509 if (ka->sa.sa_flags & SA_SIGINFO)
fcca538b 510 idx += 3;
1da177e4 511
fcca538b
NP		 512 if (__put_user(sigreturn_codes[idx], rc) ||
513 __put_user(sigreturn_codes[idx+1], rc+1))
1da177e4
LT		 514 return 1;
515
e00d349e
RK		 516 if (cpsr & MODE32_BIT) {
517 /*
518 * 32-bit code can use the new high-page
519 * signal return code support.
520 */
521 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
522 } else {
523 /*
524 * Ensure that the instruction cache sees
525 * the return code written onto the stack.
526 */
527 flush_icache_range((unsigned long)rc,
fcca538b 528 (unsigned long)(rc + 2));
e00d349e
RK		 529
530 retcode = ((unsigned long)rc) + thumb;
531 }
1da177e4
LT		 532 }
533
534 regs->ARM_r0 = usig;
535 regs->ARM_sp = (unsigned long)frame;
536 regs->ARM_lr = retcode;
537 regs->ARM_pc = handler;
538 regs->ARM_cpsr = cpsr;
539
540 return 0;
541}
542
543static int
544setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
545{
546 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
547 int err = 0;
548
549 if (!frame)
550 return 1;
551
ca195cfe
RK		 552 /*
553 * Set uc.uc_flags to a value which sc.trap_no would never have.
554 */
555 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
1da177e4 556
aca6ca10 557 err |= setup_sigframe(frame, regs, set);
1da177e4 558 if (err == 0)
fcca538b 559 err = setup_return(regs, ka, frame->retcode, frame, usig);
1da177e4
LT		 560
561 return err;
562}
563
564static int
565setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
566 sigset_t *set, struct pt_regs *regs)
567{
568 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
569 stack_t stack;
570 int err = 0;
571
572 if (!frame)
573 return 1;
574
1da177e4
LT		 575 err |= copy_siginfo_to_user(&frame->info, info);
576
cb3504e8
RK		 577 __put_user_error(0, &frame->sig.uc.uc_flags, err);
578 __put_user_error(NULL, &frame->sig.uc.uc_link, err);
1da177e4
LT		 579
580 memset(&stack, 0, sizeof(stack));
581 stack.ss_sp = (void __user *)current->sas_ss_sp;
582 stack.ss_flags = sas_ss_flags(regs->ARM_sp);
583 stack.ss_size = current->sas_ss_size;
cb3504e8 584 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
1da177e4 585
aca6ca10 586 err |= setup_sigframe(&frame->sig, regs, set);
1da177e4 587 if (err == 0)
cb3504e8 588 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
1da177e4
LT		 589
590 if (err == 0) {
591 /*
592 * For realtime signals we must also set the second and third
593 * arguments for the signal handler.
594 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
595 */
596 regs->ARM_r1 = (unsigned long)&frame->info;
cb3504e8 597 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
1da177e4
LT		 598 }
599
600 return err;
601}
602
288ddad5 603static inline void setup_syscall_restart(struct pt_regs *regs)
1da177e4
LT		 604{
605 regs->ARM_r0 = regs->ARM_ORIG_r0;
606 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
607}
608
609/*
610 * OK, we're invoking a handler
611 */
36984265 612static int
1da177e4
LT		 613handle_signal(unsigned long sig, struct k_sigaction *ka,
614 siginfo_t *info, sigset_t *oldset,
615 struct pt_regs * regs, int syscall)
616{
617 struct thread_info *thread = current_thread_info();
618 struct task_struct *tsk = current;
619 int usig = sig;
620 int ret;
621
622 /*
623 * If we were from a system call, check for system call restarting...
624 */
625 if (syscall) {
626 switch (regs->ARM_r0) {
627 case -ERESTART_RESTARTBLOCK:
628 case -ERESTARTNOHAND:
629 regs->ARM_r0 = -EINTR;
630 break;
631 case -ERESTARTSYS:
632 if (!(ka->sa.sa_flags & SA_RESTART)) {
633 regs->ARM_r0 = -EINTR;
634 break;
635 }
636 /* fallthrough */
637 case -ERESTARTNOINTR:
288ddad5 638 setup_syscall_restart(regs);
1da177e4
LT		 639 }
640 }
641
642 /*
643 * translate the signal
644 */
645 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
646 usig = thread->exec_domain->signal_invmap[usig];
647
648 /*
649 * Set up the stack frame
650 */
651 if (ka->sa.sa_flags & SA_SIGINFO)
652 ret = setup_rt_frame(usig, ka, info, oldset, regs);
653 else
654 ret = setup_frame(usig, ka, oldset, regs);
655
656 /*
657 * Check that the resulting registers are actually sane.
658 */
659 ret |= !valid_user_regs(regs);
660
69be8f18 661 if (ret != 0) {
a6c61e9d 662 force_sigsegv(sig, tsk);
36984265 663 return ret;
1da177e4
LT		 664 }
665
a6c61e9d
DJ		 666 /*
667 * Block the signal if we were successful.
668 */
669 spin_lock_irq(&tsk->sighand->siglock);
670 sigorsets(&tsk->blocked, &tsk->blocked,
671 &ka->sa.sa_mask);
672 if (!(ka->sa.sa_flags & SA_NODEFER))
673 sigaddset(&tsk->blocked, sig);
674 recalc_sigpending();
675 spin_unlock_irq(&tsk->sighand->siglock);
1da177e4 676
36984265 677 return 0;
1da177e4
LT		 678}
679
680/*
681 * Note that 'init' is a special process: it doesn't get signals it doesn't
682 * want to handle. Thus you cannot kill init even with a SIGKILL even by
683 * mistake.
684 *
685 * Note that we go through the signals twice: once to check the signals that
686 * the kernel can handle, and then we build all the user-level signal handling
687 * stack-frames in one go after that.
688 */
36984265 689static void do_signal(struct pt_regs *regs, int syscall)
1da177e4
LT		 690{
691 struct k_sigaction ka;
692 siginfo_t info;
693 int signr;
694
695 /*
696 * We want the common case to go fast, which
697 * is why we may in certain cases get here from
698 * kernel mode. Just return without doing anything
699 * if so.
700 */
701 if (!user_mode(regs))
36984265 702 return;
1da177e4 703
bdb94f3a 704 if (try_to_freeze())
1da177e4
LT		 705 goto no_signal;
706
b2a0d36f 707 single_step_clear(current);
1da177e4
LT		 708
709 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
710 if (signr > 0) {
36984265
MP		 711 sigset_t *oldset;
712
713 if (test_thread_flag(TIF_RESTORE_SIGMASK))
714 oldset = &current->saved_sigmask;
715 else
716 oldset = &current->blocked;
717 if (handle_signal(signr, &ka, &info, oldset, regs, syscall) == 0) {
718 /*
719 * A signal was successfully delivered; the saved
720 * sigmask will have been stored in the signal frame,
721 * and will be restored by sigreturn, so we can simply
722 * clear the TIF_RESTORE_SIGMASK flag.
723 */
724 if (test_thread_flag(TIF_RESTORE_SIGMASK))
725 clear_thread_flag(TIF_RESTORE_SIGMASK);
726 }
b2a0d36f 727 single_step_set(current);
36984265 728 return;
1da177e4
LT		 729 }
730
731 no_signal:
732 /*
733 * No signal to deliver to the process - restart the syscall.
734 */
735 if (syscall) {
736 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
737 if (thumb_mode(regs)) {
f606a6ff 738 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
1da177e4
LT		 739 regs->ARM_pc -= 2;
740 } else {
f606a6ff
NP		 741#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
742 regs->ARM_r7 = __NR_restart_syscall;
743 regs->ARM_pc -= 4;
744#else
1da177e4
LT		 745 u32 __user *usp;
746
ab72b007 747 regs->ARM_sp -= 4;
1da177e4
LT		 748 usp = (u32 __user *)regs->ARM_sp;
749
3336f4f0
JP		 750 if (put_user(regs->ARM_pc, usp) == 0) {
751 regs->ARM_pc = KERN_RESTART_CODE;
752 } else {
753 regs->ARM_sp += 4;
754 force_sigsegv(0, current);
755 }
f606a6ff 756#endif
1da177e4
LT		 757 }
758 }
759 if (regs->ARM_r0 == -ERESTARTNOHAND ||
760 regs->ARM_r0 == -ERESTARTSYS ||
761 regs->ARM_r0 == -ERESTARTNOINTR) {
288ddad5 762 setup_syscall_restart(regs);
1da177e4 763 }
36984265
MP		 764
765 /* If there's no signal to deliver, we just put the saved sigmask
766 * back.
767 */
768 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
769 clear_thread_flag(TIF_RESTORE_SIGMASK);
770 sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
771 }
1da177e4 772 }
b2a0d36f 773 single_step_set(current);
1da177e4
LT		 774}
775
776asmlinkage void
777do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
778{
779 if (thread_flags & _TIF_SIGPENDING)
36984265 780 do_signal(regs, syscall);
d0420c83
DH		 781
782 if (thread_flags & _TIF_NOTIFY_RESUME) {
783 clear_thread_flag(TIF_NOTIFY_RESUME);
784 tracehook_notify_resume(regs);
ee18d64c
DH		 785 if (current->replacement_session_keyring)
786 key_replace_session_keyring();
d0420c83 787 }
1da177e4 788}
Linux 6.x block layer and io_uring tree(s)