arch/arm/kernel/signal.c

   1 /*
   2  *  linux/arch/arm/kernel/signal.c
   3  *
   4  *  Copyright (C) 1995-2002 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/signal.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/personality.h>
  14 #include <linux/freezer.h>
  15
  16 #include <asm/elf.h>
  17 #include <asm/cacheflush.h>
  18 #include <asm/ucontext.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/unistd.h>
  21
  22 #include "ptrace.h"
  23 #include "signal.h"
  24
  25 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  26
  27 /*
  28  * For ARM syscalls, we encode the syscall number into the instruction.
  29  */
  30 #define SWI_SYS_SIGRETURN       (0xef000000|(__NR_sigreturn))
  31 #define SWI_SYS_RT_SIGRETURN    (0xef000000|(__NR_rt_sigreturn))
  32
  33 /*
  34  * With EABI, the syscall number has to be loaded into r7.
  35  */
  36 #define MOV_R7_NR_SIGRETURN     (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  37 #define MOV_R7_NR_RT_SIGRETURN  (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  38
  39 /*
  40  * For Thumb syscalls, we pass the syscall number via r7.  We therefore
  41  * need two 16-bit instructions.
  42  */
  43 #define SWI_THUMB_SIGRETURN     (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  44 #define SWI_THUMB_RT_SIGRETURN  (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  45
  46 const unsigned long sigreturn_codes[7] = {
  47         MOV_R7_NR_SIGRETURN,    SWI_SYS_SIGRETURN,    SWI_THUMB_SIGRETURN,
  48         MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
  49 };
  50
  51 static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
  52
  53 /*
  54  * atomically swap in the new signal mask, and wait for a signal.
  55  */
  56 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs)
  57 {
  58         sigset_t saveset;
  59
  60         mask &= _BLOCKABLE;
  61         spin_lock_irq(&current->sighand->siglock);
  62         saveset = current->blocked;
  63         siginitset(&current->blocked, mask);
  64         recalc_sigpending();
  65         spin_unlock_irq(&current->sighand->siglock);
  66         regs->ARM_r0 = -EINTR;
  67
  68         while (1) {
  69                 current->state = TASK_INTERRUPTIBLE;
  70                 schedule();
  71                 if (do_signal(&saveset, regs, 0))
  72                         return regs->ARM_r0;
  73         }
  74 }
  75
  76 asmlinkage int
  77 sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs)
  78 {
  79         sigset_t saveset, newset;
  80
  81         /* XXX: Don't preclude handling different sized sigset_t's. */
  82         if (sigsetsize != sizeof(sigset_t))
  83                 return -EINVAL;
  84
  85         if (copy_from_user(&newset, unewset, sizeof(newset)))
  86                 return -EFAULT;
  87         sigdelsetmask(&newset, ~_BLOCKABLE);
  88
  89         spin_lock_irq(&current->sighand->siglock);
  90         saveset = current->blocked;
  91         current->blocked = newset;
  92         recalc_sigpending();
  93         spin_unlock_irq(&current->sighand->siglock);
  94         regs->ARM_r0 = -EINTR;
  95
  96         while (1) {
  97                 current->state = TASK_INTERRUPTIBLE;
  98                 schedule();
  99                 if (do_signal(&saveset, regs, 0))
 100                         return regs->ARM_r0;
 101         }
 102 }
 103
 104 asmlinkage int
 105 sys_sigaction(int sig, const struct old_sigaction __user *act,
 106               struct old_sigaction __user *oact)
 107 {
 108         struct k_sigaction new_ka, old_ka;
 109         int ret;
 110
 111         if (act) {
 112                 old_sigset_t mask;
 113                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 114                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 115                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 116                         return -EFAULT;
 117                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 118                 __get_user(mask, &act->sa_mask);
 119                 siginitset(&new_ka.sa.sa_mask, mask);
 120         }
 121
 122         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 123
 124         if (!ret && oact) {
 125                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 126                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 127                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 128                         return -EFAULT;
 129                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 130                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 131         }
 132
 133         return ret;
 134 }
 135
 136 #ifdef CONFIG_CRUNCH
 137 static int preserve_crunch_context(struct crunch_sigframe *frame)
 138 {
 139         char kbuf[sizeof(*frame) + 8];
 140         struct crunch_sigframe *kframe;
 141
 142         /* the crunch context must be 64 bit aligned */
 143         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 144         kframe->magic = CRUNCH_MAGIC;
 145         kframe->size = CRUNCH_STORAGE_SIZE;
 146         crunch_task_copy(current_thread_info(), &kframe->storage);
 147         return __copy_to_user(frame, kframe, sizeof(*frame));
 148 }
 149
 150 static int restore_crunch_context(struct crunch_sigframe *frame)
 151 {
 152         char kbuf[sizeof(*frame) + 8];
 153         struct crunch_sigframe *kframe;
 154
 155         /* the crunch context must be 64 bit aligned */
 156         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 157         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 158                 return -1;
 159         if (kframe->magic != CRUNCH_MAGIC ||
 160             kframe->size != CRUNCH_STORAGE_SIZE)
 161                 return -1;
 162         crunch_task_restore(current_thread_info(), &kframe->storage);
 163         return 0;
 164 }
 165 #endif
 166
 167 #ifdef CONFIG_IWMMXT
 168
 169 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
 170 {
 171         char kbuf[sizeof(*frame) + 8];
 172         struct iwmmxt_sigframe *kframe;
 173
 174         /* the iWMMXt context must be 64 bit aligned */
 175         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 176         kframe->magic = IWMMXT_MAGIC;
 177         kframe->size = IWMMXT_STORAGE_SIZE;
 178         iwmmxt_task_copy(current_thread_info(), &kframe->storage);
 179         return __copy_to_user(frame, kframe, sizeof(*frame));
 180 }
 181
 182 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
 183 {
 184         char kbuf[sizeof(*frame) + 8];
 185         struct iwmmxt_sigframe *kframe;
 186
 187         /* the iWMMXt context must be 64 bit aligned */
 188         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 189         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 190                 return -1;
 191         if (kframe->magic != IWMMXT_MAGIC ||
 192             kframe->size != IWMMXT_STORAGE_SIZE)
 193                 return -1;
 194         iwmmxt_task_restore(current_thread_info(), &kframe->storage);
 195         return 0;
 196 }
 197
 198 #endif
 199
 200 /*
 201  * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
 202  */
 203 struct sigframe {
 204         struct ucontext uc;
 205         unsigned long retcode[2];
 206 };
 207
 208 struct rt_sigframe {
 209         struct siginfo info;
 210         struct sigframe sig;
 211 };
 212
 213 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
 214 {
 215         struct aux_sigframe __user *aux;
 216         sigset_t set;
 217         int err;
 218
 219         err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
 220         if (err == 0) {
 221                 sigdelsetmask(&set, ~_BLOCKABLE);
 222                 spin_lock_irq(&current->sighand->siglock);
 223                 current->blocked = set;
 224                 recalc_sigpending();
 225                 spin_unlock_irq(&current->sighand->siglock);
 226         }
 227
 228         __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 229         __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 230         __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 231         __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 232         __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 233         __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 234         __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 235         __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 236         __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 237         __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 238         __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 239         __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 240         __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 241         __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 242         __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 243         __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 244         __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 245
 246         err |= !valid_user_regs(regs);
 247
 248         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 249 #ifdef CONFIG_CRUNCH
 250         if (err == 0)
 251                 err |= restore_crunch_context(&aux->crunch);
 252 #endif
 253 #ifdef CONFIG_IWMMXT
 254         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 255                 err |= restore_iwmmxt_context(&aux->iwmmxt);
 256 #endif
 257 #ifdef CONFIG_VFP
 258 //      if (err == 0)
 259 //              err |= vfp_restore_state(&sf->aux.vfp);
 260 #endif
 261
 262         return err;
 263 }
 264
 265 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 266 {
 267         struct sigframe __user *frame;
 268
 269         /* Always make any pending restarted system calls return -EINTR */
 270         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 271
 272         /*
 273          * Since we stacked the signal on a 64-bit boundary,
 274          * then 'sp' should be word aligned here.  If it's
 275          * not, then the user is trying to mess with us.
 276          */
 277         if (regs->ARM_sp & 7)
 278                 goto badframe;
 279
 280         frame = (struct sigframe __user *)regs->ARM_sp;
 281
 282         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 283                 goto badframe;
 284
 285         if (restore_sigframe(regs, frame))
 286                 goto badframe;
 287
 288         /* Send SIGTRAP if we're single-stepping */
 289         if (current->ptrace & PT_SINGLESTEP) {
 290                 ptrace_cancel_bpt(current);
 291                 send_sig(SIGTRAP, current, 1);
 292         }
 293
 294         return regs->ARM_r0;
 295
 296 badframe:
 297         force_sig(SIGSEGV, current);
 298         return 0;
 299 }
 300
 301 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 302 {
 303         struct rt_sigframe __user *frame;
 304
 305         /* Always make any pending restarted system calls return -EINTR */
 306         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 307
 308         /*
 309          * Since we stacked the signal on a 64-bit boundary,
 310          * then 'sp' should be word aligned here.  If it's
 311          * not, then the user is trying to mess with us.
 312          */
 313         if (regs->ARM_sp & 7)
 314                 goto badframe;
 315
 316         frame = (struct rt_sigframe __user *)regs->ARM_sp;
 317
 318         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 319                 goto badframe;
 320
 321         if (restore_sigframe(regs, &frame->sig))
 322                 goto badframe;
 323
 324         if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
 325                 goto badframe;
 326
 327         /* Send SIGTRAP if we're single-stepping */
 328         if (current->ptrace & PT_SINGLESTEP) {
 329                 ptrace_cancel_bpt(current);
 330                 send_sig(SIGTRAP, current, 1);
 331         }
 332
 333         return regs->ARM_r0;
 334
 335 badframe:
 336         force_sig(SIGSEGV, current);
 337         return 0;
 338 }
 339
 340 static int
 341 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 342 {
 343         struct aux_sigframe __user *aux;
 344         int err = 0;
 345
 346         __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 347         __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 348         __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 349         __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 350         __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 351         __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 352         __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 353         __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 354         __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 355         __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 356         __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 357         __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 358         __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 359         __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 360         __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 361         __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 362         __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 363
 364         __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
 365         __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
 366         __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
 367         __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
 368
 369         err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
 370
 371         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 372 #ifdef CONFIG_CRUNCH
 373         if (err == 0)
 374                 err |= preserve_crunch_context(&aux->crunch);
 375 #endif
 376 #ifdef CONFIG_IWMMXT
 377         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 378                 err |= preserve_iwmmxt_context(&aux->iwmmxt);
 379 #endif
 380 #ifdef CONFIG_VFP
 381 //      if (err == 0)
 382 //              err |= vfp_save_state(&sf->aux.vfp);
 383 #endif
 384         __put_user_error(0, &aux->end_magic, err);
 385
 386         return err;
 387 }
 388
 389 static inline void __user *
 390 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 391 {
 392         unsigned long sp = regs->ARM_sp;
 393         void __user *frame;
 394
 395         /*
 396          * This is the X/Open sanctioned signal stack switching.
 397          */
 398         if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
 399                 sp = current->sas_ss_sp + current->sas_ss_size;
 400
 401         /*
 402          * ATPCS B01 mandates 8-byte alignment
 403          */
 404         frame = (void __user *)((sp - framesize) & ~7);
 405
 406         /*
 407          * Check that we can actually write to the signal frame.
 408          */
 409         if (!access_ok(VERIFY_WRITE, frame, framesize))
 410                 frame = NULL;
 411
 412         return frame;
 413 }
 414
 415 static int
 416 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 417              unsigned long __user *rc, void __user *frame, int usig)
 418 {
 419         unsigned long handler = (unsigned long)ka->sa.sa_handler;
 420         unsigned long retcode;
 421         int thumb = 0;
 422         unsigned long cpsr = regs->ARM_cpsr & ~PSR_f;
 423
 424         /*
 425          * Maybe we need to deliver a 32-bit signal to a 26-bit task.
 426          */
 427         if (ka->sa.sa_flags & SA_THIRTYTWO)
 428                 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
 429
 430 #ifdef CONFIG_ARM_THUMB
 431         if (elf_hwcap & HWCAP_THUMB) {
 432                 /*
 433                  * The LSB of the handler determines if we're going to
 434                  * be using THUMB or ARM mode for this signal handler.
 435                  */
 436                 thumb = handler & 1;
 437
 438                 if (thumb)
 439                         cpsr |= PSR_T_BIT;
 440                 else
 441                         cpsr &= ~PSR_T_BIT;
 442         }
 443 #endif
 444
 445         if (ka->sa.sa_flags & SA_RESTORER) {
 446                 retcode = (unsigned long)ka->sa.sa_restorer;
 447         } else {
 448                 unsigned int idx = thumb << 1;
 449
 450                 if (ka->sa.sa_flags & SA_SIGINFO)
 451                         idx += 3;
 452
 453                 if (__put_user(sigreturn_codes[idx],   rc) ||
 454                     __put_user(sigreturn_codes[idx+1], rc+1))
 455                         return 1;
 456
 457                 if (cpsr & MODE32_BIT) {
 458                         /*
 459                          * 32-bit code can use the new high-page
 460                          * signal return code support.
 461                          */
 462                         retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
 463                 } else {
 464                         /*
 465                          * Ensure that the instruction cache sees
 466                          * the return code written onto the stack.
 467                          */
 468                         flush_icache_range((unsigned long)rc,
 469                                            (unsigned long)(rc + 2));
 470
 471                         retcode = ((unsigned long)rc) + thumb;
 472                 }
 473         }
 474
 475         regs->ARM_r0 = usig;
 476         regs->ARM_sp = (unsigned long)frame;
 477         regs->ARM_lr = retcode;
 478         regs->ARM_pc = handler;
 479         regs->ARM_cpsr = cpsr;
 480
 481         return 0;
 482 }
 483
 484 static int
 485 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
 486 {
 487         struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 488         int err = 0;
 489
 490         if (!frame)
 491                 return 1;
 492
 493         /*
 494          * Set uc.uc_flags to a value which sc.trap_no would never have.
 495          */
 496         __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
 497
 498         err |= setup_sigframe(frame, regs, set);
 499         if (err == 0)
 500                 err = setup_return(regs, ka, frame->retcode, frame, usig);
 501
 502         return err;
 503 }
 504
 505 static int
 506 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 507                sigset_t *set, struct pt_regs *regs)
 508 {
 509         struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 510         stack_t stack;
 511         int err = 0;
 512
 513         if (!frame)
 514                 return 1;
 515
 516         err |= copy_siginfo_to_user(&frame->info, info);
 517
 518         __put_user_error(0, &frame->sig.uc.uc_flags, err);
 519         __put_user_error(NULL, &frame->sig.uc.uc_link, err);
 520
 521         memset(&stack, 0, sizeof(stack));
 522         stack.ss_sp = (void __user *)current->sas_ss_sp;
 523         stack.ss_flags = sas_ss_flags(regs->ARM_sp);
 524         stack.ss_size = current->sas_ss_size;
 525         err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
 526
 527         err |= setup_sigframe(&frame->sig, regs, set);
 528         if (err == 0)
 529                 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
 530
 531         if (err == 0) {
 532                 /*
 533                  * For realtime signals we must also set the second and third
 534                  * arguments for the signal handler.
 535                  *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
 536                  */
 537                 regs->ARM_r1 = (unsigned long)&frame->info;
 538                 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
 539         }
 540
 541         return err;
 542 }
 543
 544 static inline void restart_syscall(struct pt_regs *regs)
 545 {
 546         regs->ARM_r0 = regs->ARM_ORIG_r0;
 547         regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
 548 }
 549
 550 /*
 551  * OK, we're invoking a handler
 552  */
 553 static void
 554 handle_signal(unsigned long sig, struct k_sigaction *ka,
 555               siginfo_t *info, sigset_t *oldset,
 556               struct pt_regs * regs, int syscall)
 557 {
 558         struct thread_info *thread = current_thread_info();
 559         struct task_struct *tsk = current;
 560         int usig = sig;
 561         int ret;
 562
 563         /*
 564          * If we were from a system call, check for system call restarting...
 565          */
 566         if (syscall) {
 567                 switch (regs->ARM_r0) {
 568                 case -ERESTART_RESTARTBLOCK:
 569                 case -ERESTARTNOHAND:
 570                         regs->ARM_r0 = -EINTR;
 571                         break;
 572                 case -ERESTARTSYS:
 573                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 574                                 regs->ARM_r0 = -EINTR;
 575                                 break;
 576                         }
 577                         /* fallthrough */
 578                 case -ERESTARTNOINTR:
 579                         restart_syscall(regs);
 580                 }
 581         }
 582
 583         /*
 584          * translate the signal
 585          */
 586         if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
 587                 usig = thread->exec_domain->signal_invmap[usig];
 588
 589         /*
 590          * Set up the stack frame
 591          */
 592         if (ka->sa.sa_flags & SA_SIGINFO)
 593                 ret = setup_rt_frame(usig, ka, info, oldset, regs);
 594         else
 595                 ret = setup_frame(usig, ka, oldset, regs);
 596
 597         /*
 598          * Check that the resulting registers are actually sane.
 599          */
 600         ret |= !valid_user_regs(regs);
 601
 602         if (ret != 0) {
 603                 force_sigsegv(sig, tsk);
 604                 return;
 605         }
 606
 607         /*
 608          * Block the signal if we were successful.
 609          */
 610         spin_lock_irq(&tsk->sighand->siglock);
 611         sigorsets(&tsk->blocked, &tsk->blocked,
 612                   &ka->sa.sa_mask);
 613         if (!(ka->sa.sa_flags & SA_NODEFER))
 614                 sigaddset(&tsk->blocked, sig);
 615         recalc_sigpending();
 616         spin_unlock_irq(&tsk->sighand->siglock);
 617
 618 }
 619
 620 /*
 621  * Note that 'init' is a special process: it doesn't get signals it doesn't
 622  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 623  * mistake.
 624  *
 625  * Note that we go through the signals twice: once to check the signals that
 626  * the kernel can handle, and then we build all the user-level signal handling
 627  * stack-frames in one go after that.
 628  */
 629 static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
 630 {
 631         struct k_sigaction ka;
 632         siginfo_t info;
 633         int signr;
 634
 635         /*
 636          * We want the common case to go fast, which
 637          * is why we may in certain cases get here from
 638          * kernel mode. Just return without doing anything
 639          * if so.
 640          */
 641         if (!user_mode(regs))
 642                 return 0;
 643
 644         if (try_to_freeze())
 645                 goto no_signal;
 646
 647         if (current->ptrace & PT_SINGLESTEP)
 648                 ptrace_cancel_bpt(current);
 649
 650         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 651         if (signr > 0) {
 652                 handle_signal(signr, &ka, &info, oldset, regs, syscall);
 653                 if (current->ptrace & PT_SINGLESTEP)
 654                         ptrace_set_bpt(current);
 655                 return 1;
 656         }
 657
 658  no_signal:
 659         /*
 660          * No signal to deliver to the process - restart the syscall.
 661          */
 662         if (syscall) {
 663                 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
 664                         if (thumb_mode(regs)) {
 665                                 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
 666                                 regs->ARM_pc -= 2;
 667                         } else {
 668 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
 669                                 regs->ARM_r7 = __NR_restart_syscall;
 670                                 regs->ARM_pc -= 4;
 671 #else
 672                                 u32 __user *usp;
 673                                 u32 swival = __NR_restart_syscall;
 674
 675                                 regs->ARM_sp -= 12;
 676                                 usp = (u32 __user *)regs->ARM_sp;
 677
 678                                 /*
 679                                  * Either we supports OABI only, or we have
 680                                  * EABI with the OABI compat layer enabled.
 681                                  * In the later case we don't know if user
 682                                  * space is EABI or not, and if not we must
 683                                  * not clobber r7.  Always using the OABI
 684                                  * syscall solves that issue and works for
 685                                  * all those cases.
 686                                  */
 687                                 swival = swival - __NR_SYSCALL_BASE + __NR_OABI_SYSCALL_BASE;
 688
 689                                 put_user(regs->ARM_pc, &usp[0]);
 690                                 /* swi __NR_restart_syscall */
 691                                 put_user(0xef000000 | swival, &usp[1]);
 692                                 /* ldr  pc, [sp], #12 */
 693                                 put_user(0xe49df00c, &usp[2]);
 694
 695                                 flush_icache_range((unsigned long)usp,
 696                                                    (unsigned long)(usp + 3));
 697
 698                                 regs->ARM_pc = regs->ARM_sp + 4;
 699 #endif
 700                         }
 701                 }
 702                 if (regs->ARM_r0 == -ERESTARTNOHAND ||
 703                     regs->ARM_r0 == -ERESTARTSYS ||
 704                     regs->ARM_r0 == -ERESTARTNOINTR) {
 705                         restart_syscall(regs);
 706                 }
 707         }
 708         if (current->ptrace & PT_SINGLESTEP)
 709                 ptrace_set_bpt(current);
 710         return 0;
 711 }
 712
 713 asmlinkage void
 714 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 715 {
 716         if (thread_flags & _TIF_SIGPENDING)
 717                 do_signal(&current->blocked, regs, syscall);
 718 }