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/config.h>
  11 #include <linux/errno.h>
  12 #include <linux/signal.h>
  13 #include <linux/ptrace.h>
  14 #include <linux/personality.h>
  15
  16 #include <asm/cacheflush.h>
  17 #include <asm/ucontext.h>
  18 #include <asm/uaccess.h>
  19 #include <asm/unistd.h>
  20
  21 #include "ptrace.h"
  22 #include "signal.h"
  23
  24 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  25
  26 /*
  27  * For ARM syscalls, we encode the syscall number into the instruction.
  28  */
  29 #define SWI_SYS_SIGRETURN       (0xef000000|(__NR_sigreturn))
  30 #define SWI_SYS_RT_SIGRETURN    (0xef000000|(__NR_rt_sigreturn))
  31
  32 /*
  33  * For Thumb syscalls, we pass the syscall number via r7.  We therefore
  34  * need two 16-bit instructions.
  35  */
  36 #define SWI_THUMB_SIGRETURN     (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  37 #define SWI_THUMB_RT_SIGRETURN  (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  38
  39 const unsigned long sigreturn_codes[4] = {
  40         SWI_SYS_SIGRETURN,      SWI_THUMB_SIGRETURN,
  41         SWI_SYS_RT_SIGRETURN,   SWI_THUMB_RT_SIGRETURN
  42 };
  43
  44 static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
  45
  46 /*
  47  * atomically swap in the new signal mask, and wait for a signal.
  48  */
  49 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs)
  50 {
  51         sigset_t saveset;
  52
  53         mask &= _BLOCKABLE;
  54         spin_lock_irq(&current->sighand->siglock);
  55         saveset = current->blocked;
  56         siginitset(&current->blocked, mask);
  57         recalc_sigpending();
  58         spin_unlock_irq(&current->sighand->siglock);
  59         regs->ARM_r0 = -EINTR;
  60
  61         while (1) {
  62                 current->state = TASK_INTERRUPTIBLE;
  63                 schedule();
  64                 if (do_signal(&saveset, regs, 0))
  65                         return regs->ARM_r0;
  66         }
  67 }
  68
  69 asmlinkage int
  70 sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs)
  71 {
  72         sigset_t saveset, newset;
  73
  74         /* XXX: Don't preclude handling different sized sigset_t's. */
  75         if (sigsetsize != sizeof(sigset_t))
  76                 return -EINVAL;
  77
  78         if (copy_from_user(&newset, unewset, sizeof(newset)))
  79                 return -EFAULT;
  80         sigdelsetmask(&newset, ~_BLOCKABLE);
  81
  82         spin_lock_irq(&current->sighand->siglock);
  83         saveset = current->blocked;
  84         current->blocked = newset;
  85         recalc_sigpending();
  86         spin_unlock_irq(&current->sighand->siglock);
  87         regs->ARM_r0 = -EINTR;
  88
  89         while (1) {
  90                 current->state = TASK_INTERRUPTIBLE;
  91                 schedule();
  92                 if (do_signal(&saveset, regs, 0))
  93                         return regs->ARM_r0;
  94         }
  95 }
  96
  97 asmlinkage int
  98 sys_sigaction(int sig, const struct old_sigaction __user *act,
  99               struct old_sigaction __user *oact)
 100 {
 101         struct k_sigaction new_ka, old_ka;
 102         int ret;
 103
 104         if (act) {
 105                 old_sigset_t mask;
 106                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 107                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 108                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 109                         return -EFAULT;
 110                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 111                 __get_user(mask, &act->sa_mask);
 112                 siginitset(&new_ka.sa.sa_mask, mask);
 113         }
 114
 115         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 116
 117         if (!ret && oact) {
 118                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 119                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 120                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 121                         return -EFAULT;
 122                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 123                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 124         }
 125
 126         return ret;
 127 }
 128
 129 #ifdef CONFIG_IWMMXT
 130
 131 /* iwmmxt_area is 0x98 bytes long, preceeded by 8 bytes of signature */
 132 #define IWMMXT_STORAGE_SIZE     (0x98 + 8)
 133 #define IWMMXT_MAGIC0           0x12ef842a
 134 #define IWMMXT_MAGIC1           0x1c07ca71
 135
 136 struct iwmmxt_sigframe {
 137         unsigned long   magic0;
 138         unsigned long   magic1;
 139         unsigned long   storage[0x98/4];
 140 };
 141
 142 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
 143 {
 144         char kbuf[sizeof(*frame) + 8];
 145         struct iwmmxt_sigframe *kframe;
 146
 147         /* the iWMMXt context must be 64 bit aligned */
 148         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 149         kframe->magic0 = IWMMXT_MAGIC0;
 150         kframe->magic1 = IWMMXT_MAGIC1;
 151         iwmmxt_task_copy(current_thread_info(), &kframe->storage);
 152         return __copy_to_user(frame, kframe, sizeof(*frame));
 153 }
 154
 155 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
 156 {
 157         char kbuf[sizeof(*frame) + 8];
 158         struct iwmmxt_sigframe *kframe;
 159
 160         /* the iWMMXt context must be 64 bit aligned */
 161         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 162         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 163                 return -1;
 164         if (kframe->magic0 != IWMMXT_MAGIC0 ||
 165             kframe->magic1 != IWMMXT_MAGIC1)
 166                 return -1;
 167         iwmmxt_task_restore(current_thread_info(), &kframe->storage);
 168         return 0;
 169 }
 170
 171 #endif
 172
 173 /*
 174  * Auxiliary signal frame.  This saves stuff like FP state.
 175  * The layout of this structure is not part of the user ABI.
 176  */
 177 struct aux_sigframe {
 178 #ifdef CONFIG_IWMMXT
 179         struct iwmmxt_sigframe  iwmmxt;
 180 #endif
 181 #ifdef CONFIG_VFP
 182         union vfp_state         vfp;
 183 #endif
 184 };
 185
 186 /*
 187  * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
 188  */
 189 struct sigframe {
 190         struct sigcontext sc;
 191         unsigned long extramask[_NSIG_WORDS-1];
 192         unsigned long retcode;
 193         struct aux_sigframe aux __attribute__((aligned(8)));
 194 };
 195
 196 struct rt_sigframe {
 197         struct siginfo __user *pinfo;
 198         void __user *puc;
 199         struct siginfo info;
 200         struct ucontext uc;
 201         unsigned long retcode;
 202         struct aux_sigframe aux __attribute__((aligned(8)));
 203 };
 204
 205 static int
 206 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
 207                    struct aux_sigframe __user *aux)
 208 {
 209         int err = 0;
 210
 211         __get_user_error(regs->ARM_r0, &sc->arm_r0, err);
 212         __get_user_error(regs->ARM_r1, &sc->arm_r1, err);
 213         __get_user_error(regs->ARM_r2, &sc->arm_r2, err);
 214         __get_user_error(regs->ARM_r3, &sc->arm_r3, err);
 215         __get_user_error(regs->ARM_r4, &sc->arm_r4, err);
 216         __get_user_error(regs->ARM_r5, &sc->arm_r5, err);
 217         __get_user_error(regs->ARM_r6, &sc->arm_r6, err);
 218         __get_user_error(regs->ARM_r7, &sc->arm_r7, err);
 219         __get_user_error(regs->ARM_r8, &sc->arm_r8, err);
 220         __get_user_error(regs->ARM_r9, &sc->arm_r9, err);
 221         __get_user_error(regs->ARM_r10, &sc->arm_r10, err);
 222         __get_user_error(regs->ARM_fp, &sc->arm_fp, err);
 223         __get_user_error(regs->ARM_ip, &sc->arm_ip, err);
 224         __get_user_error(regs->ARM_sp, &sc->arm_sp, err);
 225         __get_user_error(regs->ARM_lr, &sc->arm_lr, err);
 226         __get_user_error(regs->ARM_pc, &sc->arm_pc, err);
 227         __get_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
 228
 229         err |= !valid_user_regs(regs);
 230
 231 #ifdef CONFIG_IWMMXT
 232         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 233                 err |= restore_iwmmxt_context(&aux->iwmmxt);
 234 #endif
 235 #ifdef CONFIG_VFP
 236 //      if (err == 0)
 237 //              err |= vfp_restore_state(&aux->vfp);
 238 #endif
 239
 240         return err;
 241 }
 242
 243 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 244 {
 245         struct sigframe __user *frame;
 246         sigset_t set;
 247
 248         /* Always make any pending restarted system calls return -EINTR */
 249         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 250
 251         /*
 252          * Since we stacked the signal on a 64-bit boundary,
 253          * then 'sp' should be word aligned here.  If it's
 254          * not, then the user is trying to mess with us.
 255          */
 256         if (regs->ARM_sp & 7)
 257                 goto badframe;
 258
 259         frame = (struct sigframe __user *)regs->ARM_sp;
 260
 261         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 262                 goto badframe;
 263         if (__get_user(set.sig[0], &frame->sc.oldmask)
 264             || (_NSIG_WORDS > 1
 265                 && __copy_from_user(&set.sig[1], &frame->extramask,
 266                                     sizeof(frame->extramask))))
 267                 goto badframe;
 268
 269         sigdelsetmask(&set, ~_BLOCKABLE);
 270         spin_lock_irq(&current->sighand->siglock);
 271         current->blocked = set;
 272         recalc_sigpending();
 273         spin_unlock_irq(&current->sighand->siglock);
 274
 275         if (restore_sigcontext(regs, &frame->sc, &frame->aux))
 276                 goto badframe;
 277
 278         /* Send SIGTRAP if we're single-stepping */
 279         if (current->ptrace & PT_SINGLESTEP) {
 280                 ptrace_cancel_bpt(current);
 281                 send_sig(SIGTRAP, current, 1);
 282         }
 283
 284         return regs->ARM_r0;
 285
 286 badframe:
 287         force_sig(SIGSEGV, current);
 288         return 0;
 289 }
 290
 291 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 292 {
 293         struct rt_sigframe __user *frame;
 294         sigset_t set;
 295
 296         /* Always make any pending restarted system calls return -EINTR */
 297         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 298
 299         /*
 300          * Since we stacked the signal on a 64-bit boundary,
 301          * then 'sp' should be word aligned here.  If it's
 302          * not, then the user is trying to mess with us.
 303          */
 304         if (regs->ARM_sp & 7)
 305                 goto badframe;
 306
 307         frame = (struct rt_sigframe __user *)regs->ARM_sp;
 308
 309         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 310                 goto badframe;
 311         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 312                 goto badframe;
 313
 314         sigdelsetmask(&set, ~_BLOCKABLE);
 315         spin_lock_irq(&current->sighand->siglock);
 316         current->blocked = set;
 317         recalc_sigpending();
 318         spin_unlock_irq(&current->sighand->siglock);
 319
 320         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &frame->aux))
 321                 goto badframe;
 322
 323         if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
 324                 goto badframe;
 325
 326         /* Send SIGTRAP if we're single-stepping */
 327         if (current->ptrace & PT_SINGLESTEP) {
 328                 ptrace_cancel_bpt(current);
 329                 send_sig(SIGTRAP, current, 1);
 330         }
 331
 332         return regs->ARM_r0;
 333
 334 badframe:
 335         force_sig(SIGSEGV, current);
 336         return 0;
 337 }
 338
 339 static int
 340 setup_sigcontext(struct sigcontext __user *sc, struct aux_sigframe __user *aux,
 341                  struct pt_regs *regs, unsigned long mask)
 342 {
 343         int err = 0;
 344
 345         __put_user_error(regs->ARM_r0, &sc->arm_r0, err);
 346         __put_user_error(regs->ARM_r1, &sc->arm_r1, err);
 347         __put_user_error(regs->ARM_r2, &sc->arm_r2, err);
 348         __put_user_error(regs->ARM_r3, &sc->arm_r3, err);
 349         __put_user_error(regs->ARM_r4, &sc->arm_r4, err);
 350         __put_user_error(regs->ARM_r5, &sc->arm_r5, err);
 351         __put_user_error(regs->ARM_r6, &sc->arm_r6, err);
 352         __put_user_error(regs->ARM_r7, &sc->arm_r7, err);
 353         __put_user_error(regs->ARM_r8, &sc->arm_r8, err);
 354         __put_user_error(regs->ARM_r9, &sc->arm_r9, err);
 355         __put_user_error(regs->ARM_r10, &sc->arm_r10, err);
 356         __put_user_error(regs->ARM_fp, &sc->arm_fp, err);
 357         __put_user_error(regs->ARM_ip, &sc->arm_ip, err);
 358         __put_user_error(regs->ARM_sp, &sc->arm_sp, err);
 359         __put_user_error(regs->ARM_lr, &sc->arm_lr, err);
 360         __put_user_error(regs->ARM_pc, &sc->arm_pc, err);
 361         __put_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
 362
 363         __put_user_error(current->thread.trap_no, &sc->trap_no, err);
 364         __put_user_error(current->thread.error_code, &sc->error_code, err);
 365         __put_user_error(current->thread.address, &sc->fault_address, err);
 366         __put_user_error(mask, &sc->oldmask, err);
 367
 368 #ifdef CONFIG_IWMMXT
 369         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 370                 err |= preserve_iwmmxt_context(&aux->iwmmxt);
 371 #endif
 372 #ifdef CONFIG_VFP
 373 //      if (err == 0)
 374 //              err |= vfp_save_state(&aux->vfp);
 375 #endif
 376
 377         return err;
 378 }
 379
 380 static inline void __user *
 381 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 382 {
 383         unsigned long sp = regs->ARM_sp;
 384         void __user *frame;
 385
 386         /*
 387          * This is the X/Open sanctioned signal stack switching.
 388          */
 389         if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
 390                 sp = current->sas_ss_sp + current->sas_ss_size;
 391
 392         /*
 393          * ATPCS B01 mandates 8-byte alignment
 394          */
 395         frame = (void __user *)((sp - framesize) & ~7);
 396
 397         /*
 398          * Check that we can actually write to the signal frame.
 399          */
 400         if (!access_ok(VERIFY_WRITE, frame, framesize))
 401                 frame = NULL;
 402
 403         return frame;
 404 }
 405
 406 static int
 407 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 408              unsigned long __user *rc, void __user *frame, int usig)
 409 {
 410         unsigned long handler = (unsigned long)ka->sa.sa_handler;
 411         unsigned long retcode;
 412         int thumb = 0;
 413         unsigned long cpsr = regs->ARM_cpsr & ~PSR_f;
 414
 415         /*
 416          * Maybe we need to deliver a 32-bit signal to a 26-bit task.
 417          */
 418         if (ka->sa.sa_flags & SA_THIRTYTWO)
 419                 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
 420
 421 #ifdef CONFIG_ARM_THUMB
 422         if (elf_hwcap & HWCAP_THUMB) {
 423                 /*
 424                  * The LSB of the handler determines if we're going to
 425                  * be using THUMB or ARM mode for this signal handler.
 426                  */
 427                 thumb = handler & 1;
 428
 429                 if (thumb)
 430                         cpsr |= PSR_T_BIT;
 431                 else
 432                         cpsr &= ~PSR_T_BIT;
 433         }
 434 #endif
 435
 436         if (ka->sa.sa_flags & SA_RESTORER) {
 437                 retcode = (unsigned long)ka->sa.sa_restorer;
 438         } else {
 439                 unsigned int idx = thumb;
 440
 441                 if (ka->sa.sa_flags & SA_SIGINFO)
 442                         idx += 2;
 443
 444                 if (__put_user(sigreturn_codes[idx], rc))
 445                         return 1;
 446
 447                 if (cpsr & MODE32_BIT) {
 448                         /*
 449                          * 32-bit code can use the new high-page
 450                          * signal return code support.
 451                          */
 452                         retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
 453                 } else {
 454                         /*
 455                          * Ensure that the instruction cache sees
 456                          * the return code written onto the stack.
 457                          */
 458                         flush_icache_range((unsigned long)rc,
 459                                            (unsigned long)(rc + 1));
 460
 461                         retcode = ((unsigned long)rc) + thumb;
 462                 }
 463         }
 464
 465         regs->ARM_r0 = usig;
 466         regs->ARM_sp = (unsigned long)frame;
 467         regs->ARM_lr = retcode;
 468         regs->ARM_pc = handler;
 469         regs->ARM_cpsr = cpsr;
 470
 471         return 0;
 472 }
 473
 474 static int
 475 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
 476 {
 477         struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 478         int err = 0;
 479
 480         if (!frame)
 481                 return 1;
 482
 483         err |= setup_sigcontext(&frame->sc, &frame->aux, regs, set->sig[0]);
 484
 485         if (_NSIG_WORDS > 1) {
 486                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 487                                       sizeof(frame->extramask));
 488         }
 489
 490         if (err == 0)
 491                 err = setup_return(regs, ka, &frame->retcode, frame, usig);
 492
 493         return err;
 494 }
 495
 496 static int
 497 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 498                sigset_t *set, struct pt_regs *regs)
 499 {
 500         struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 501         stack_t stack;
 502         int err = 0;
 503
 504         if (!frame)
 505                 return 1;
 506
 507         __put_user_error(&frame->info, &frame->pinfo, err);
 508         __put_user_error(&frame->uc, &frame->puc, err);
 509         err |= copy_siginfo_to_user(&frame->info, info);
 510
 511         __put_user_error(0, &frame->uc.uc_flags, err);
 512         __put_user_error(NULL, &frame->uc.uc_link, err);
 513
 514         memset(&stack, 0, sizeof(stack));
 515         stack.ss_sp = (void __user *)current->sas_ss_sp;
 516         stack.ss_flags = sas_ss_flags(regs->ARM_sp);
 517         stack.ss_size = current->sas_ss_size;
 518         err |= __copy_to_user(&frame->uc.uc_stack, &stack, sizeof(stack));
 519
 520         err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->aux,
 521                                 regs, set->sig[0]);
 522         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 523
 524         if (err == 0)
 525                 err = setup_return(regs, ka, &frame->retcode, frame, usig);
 526
 527         if (err == 0) {
 528                 /*
 529                  * For realtime signals we must also set the second and third
 530                  * arguments for the signal handler.
 531                  *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
 532                  */
 533                 regs->ARM_r1 = (unsigned long)&frame->info;
 534                 regs->ARM_r2 = (unsigned long)&frame->uc;
 535         }
 536
 537         return err;
 538 }
 539
 540 static inline void restart_syscall(struct pt_regs *regs)
 541 {
 542         regs->ARM_r0 = regs->ARM_ORIG_r0;
 543         regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
 544 }
 545
 546 /*
 547  * OK, we're invoking a handler
 548  */
 549 static void
 550 handle_signal(unsigned long sig, struct k_sigaction *ka,
 551               siginfo_t *info, sigset_t *oldset,
 552               struct pt_regs * regs, int syscall)
 553 {
 554         struct thread_info *thread = current_thread_info();
 555         struct task_struct *tsk = current;
 556         int usig = sig;
 557         int ret;
 558
 559         /*
 560          * If we were from a system call, check for system call restarting...
 561          */
 562         if (syscall) {
 563                 switch (regs->ARM_r0) {
 564                 case -ERESTART_RESTARTBLOCK:
 565                 case -ERESTARTNOHAND:
 566                         regs->ARM_r0 = -EINTR;
 567                         break;
 568                 case -ERESTARTSYS:
 569                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 570                                 regs->ARM_r0 = -EINTR;
 571                                 break;
 572                         }
 573                         /* fallthrough */
 574                 case -ERESTARTNOINTR:
 575                         restart_syscall(regs);
 576                 }
 577         }
 578
 579         /*
 580          * translate the signal
 581          */
 582         if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
 583                 usig = thread->exec_domain->signal_invmap[usig];
 584
 585         /*
 586          * Set up the stack frame
 587          */
 588         if (ka->sa.sa_flags & SA_SIGINFO)
 589                 ret = setup_rt_frame(usig, ka, info, oldset, regs);
 590         else
 591                 ret = setup_frame(usig, ka, oldset, regs);
 592
 593         /*
 594          * Check that the resulting registers are actually sane.
 595          */
 596         ret |= !valid_user_regs(regs);
 597
 598         if (ret != 0) {
 599                 force_sigsegv(sig, tsk);
 600                 return;
 601         }
 602
 603         /*
 604          * Block the signal if we were successful.
 605          */
 606         spin_lock_irq(&tsk->sighand->siglock);
 607         sigorsets(&tsk->blocked, &tsk->blocked,
 608                   &ka->sa.sa_mask);
 609         if (!(ka->sa.sa_flags & SA_NODEFER))
 610                 sigaddset(&tsk->blocked, sig);
 611         recalc_sigpending();
 612         spin_unlock_irq(&tsk->sighand->siglock);
 613
 614 }
 615
 616 /*
 617  * Note that 'init' is a special process: it doesn't get signals it doesn't
 618  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 619  * mistake.
 620  *
 621  * Note that we go through the signals twice: once to check the signals that
 622  * the kernel can handle, and then we build all the user-level signal handling
 623  * stack-frames in one go after that.
 624  */
 625 static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
 626 {
 627         struct k_sigaction ka;
 628         siginfo_t info;
 629         int signr;
 630
 631         /*
 632          * We want the common case to go fast, which
 633          * is why we may in certain cases get here from
 634          * kernel mode. Just return without doing anything
 635          * if so.
 636          */
 637         if (!user_mode(regs))
 638                 return 0;
 639
 640         if (try_to_freeze())
 641                 goto no_signal;
 642
 643         if (current->ptrace & PT_SINGLESTEP)
 644                 ptrace_cancel_bpt(current);
 645
 646         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 647         if (signr > 0) {
 648                 handle_signal(signr, &ka, &info, oldset, regs, syscall);
 649                 if (current->ptrace & PT_SINGLESTEP)
 650                         ptrace_set_bpt(current);
 651                 return 1;
 652         }
 653
 654  no_signal:
 655         /*
 656          * No signal to deliver to the process - restart the syscall.
 657          */
 658         if (syscall) {
 659                 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
 660                         if (thumb_mode(regs)) {
 661                                 regs->ARM_r7 = __NR_restart_syscall;
 662                                 regs->ARM_pc -= 2;
 663                         } else {
 664                                 u32 __user *usp;
 665
 666                                 regs->ARM_sp -= 12;
 667                                 usp = (u32 __user *)regs->ARM_sp;
 668
 669                                 put_user(regs->ARM_pc, &usp[0]);
 670                                 /* swi __NR_restart_syscall */
 671                                 put_user(0xef000000 | __NR_restart_syscall, &usp[1]);
 672                                 /* ldr  pc, [sp], #12 */
 673                                 put_user(0xe49df00c, &usp[2]);
 674
 675                                 flush_icache_range((unsigned long)usp,
 676                                                    (unsigned long)(usp + 3));
 677
 678                                 regs->ARM_pc = regs->ARM_sp + 4;
 679                         }
 680                 }
 681                 if (regs->ARM_r0 == -ERESTARTNOHAND ||
 682                     regs->ARM_r0 == -ERESTARTSYS ||
 683                     regs->ARM_r0 == -ERESTARTNOINTR) {
 684                         restart_syscall(regs);
 685                 }
 686         }
 687         if (current->ptrace & PT_SINGLESTEP)
 688                 ptrace_set_bpt(current);
 689         return 0;
 690 }
 691
 692 asmlinkage void
 693 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 694 {
 695         if (thread_flags & _TIF_SIGPENDING)
 696                 do_signal(&current->blocked, regs, syscall);
 697 }