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  * With EABI, the syscall number has to be loaded into r7.
  34  */
  35 #define MOV_R7_NR_SIGRETURN     (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  36 #define MOV_R7_NR_RT_SIGRETURN  (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  37
  38 /*
  39  * For Thumb syscalls, we pass the syscall number via r7.  We therefore
  40  * need two 16-bit instructions.
  41  */
  42 #define SWI_THUMB_SIGRETURN     (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  43 #define SWI_THUMB_RT_SIGRETURN  (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  44
  45 const unsigned long sigreturn_codes[7] = {
  46         MOV_R7_NR_SIGRETURN,    SWI_SYS_SIGRETURN,    SWI_THUMB_SIGRETURN,
  47         MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
  48 };
  49
  50 static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
  51
  52 /*
  53  * atomically swap in the new signal mask, and wait for a signal.
  54  */
  55 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs)
  56 {
  57         sigset_t saveset;
  58
  59         mask &= _BLOCKABLE;
  60         spin_lock_irq(&current->sighand->siglock);
  61         saveset = current->blocked;
  62         siginitset(&current->blocked, mask);
  63         recalc_sigpending();
  64         spin_unlock_irq(&current->sighand->siglock);
  65         regs->ARM_r0 = -EINTR;
  66
  67         while (1) {
  68                 current->state = TASK_INTERRUPTIBLE;
  69                 schedule();
  70                 if (do_signal(&saveset, regs, 0))
  71                         return regs->ARM_r0;
  72         }
  73 }
  74
  75 asmlinkage int
  76 sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs)
  77 {
  78         sigset_t saveset, newset;
  79
  80         /* XXX: Don't preclude handling different sized sigset_t's. */
  81         if (sigsetsize != sizeof(sigset_t))
  82                 return -EINVAL;
  83
  84         if (copy_from_user(&newset, unewset, sizeof(newset)))
  85                 return -EFAULT;
  86         sigdelsetmask(&newset, ~_BLOCKABLE);
  87
  88         spin_lock_irq(&current->sighand->siglock);
  89         saveset = current->blocked;
  90         current->blocked = newset;
  91         recalc_sigpending();
  92         spin_unlock_irq(&current->sighand->siglock);
  93         regs->ARM_r0 = -EINTR;
  94
  95         while (1) {
  96                 current->state = TASK_INTERRUPTIBLE;
  97                 schedule();
  98                 if (do_signal(&saveset, regs, 0))
  99                         return regs->ARM_r0;
 100         }
 101 }
 102
 103 asmlinkage int
 104 sys_sigaction(int sig, const struct old_sigaction __user *act,
 105               struct old_sigaction __user *oact)
 106 {
 107         struct k_sigaction new_ka, old_ka;
 108         int ret;
 109
 110         if (act) {
 111                 old_sigset_t mask;
 112                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 113                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 114                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 115                         return -EFAULT;
 116                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 117                 __get_user(mask, &act->sa_mask);
 118                 siginitset(&new_ka.sa.sa_mask, mask);
 119         }
 120
 121         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 122
 123         if (!ret && oact) {
 124                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 125                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 126                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 127                         return -EFAULT;
 128                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 129                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 130         }
 131
 132         return ret;
 133 }
 134
 135 #ifdef CONFIG_IWMMXT
 136
 137 /* iwmmxt_area is 0x98 bytes long, preceeded by 8 bytes of signature */
 138 #define IWMMXT_STORAGE_SIZE     (0x98 + 8)
 139 #define IWMMXT_MAGIC0           0x12ef842a
 140 #define IWMMXT_MAGIC1           0x1c07ca71
 141
 142 struct iwmmxt_sigframe {
 143         unsigned long   magic0;
 144         unsigned long   magic1;
 145         unsigned long   storage[0x98/4];
 146 };
 147
 148 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
 149 {
 150         char kbuf[sizeof(*frame) + 8];
 151         struct iwmmxt_sigframe *kframe;
 152
 153         /* the iWMMXt context must be 64 bit aligned */
 154         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 155         kframe->magic0 = IWMMXT_MAGIC0;
 156         kframe->magic1 = IWMMXT_MAGIC1;
 157         iwmmxt_task_copy(current_thread_info(), &kframe->storage);
 158         return __copy_to_user(frame, kframe, sizeof(*frame));
 159 }
 160
 161 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
 162 {
 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;
 170         if (kframe->magic0 != IWMMXT_MAGIC0 ||
 171             kframe->magic1 != IWMMXT_MAGIC1)
 172                 return -1;
 173         iwmmxt_task_restore(current_thread_info(), &kframe->storage);
 174         return 0;
 175 }
 176
 177 #endif
 178
 179 /*
 180  * Auxiliary signal frame.  This saves stuff like FP state.
 181  * The layout of this structure is not part of the user ABI.
 182  */
 183 struct aux_sigframe {
 184 #ifdef CONFIG_IWMMXT
 185         struct iwmmxt_sigframe  iwmmxt;
 186 #endif
 187 #ifdef CONFIG_VFP
 188         union vfp_state         vfp;
 189 #endif
 190 };
 191
 192 /*
 193  * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
 194  */
 195 struct sigframe {
 196         struct ucontext uc;
 197         unsigned long retcode[2];
 198         struct aux_sigframe aux __attribute__((aligned(8)));
 199 };
 200
 201 struct rt_sigframe {
 202         struct siginfo info;
 203         struct sigframe sig;
 204 };
 205
 206 static int
 207 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
 208                    struct aux_sigframe __user *aux)
 209 {
 210         int err = 0;
 211
 212         __get_user_error(regs->ARM_r0, &sc->arm_r0, err);
 213         __get_user_error(regs->ARM_r1, &sc->arm_r1, err);
 214         __get_user_error(regs->ARM_r2, &sc->arm_r2, err);
 215         __get_user_error(regs->ARM_r3, &sc->arm_r3, err);
 216         __get_user_error(regs->ARM_r4, &sc->arm_r4, err);
 217         __get_user_error(regs->ARM_r5, &sc->arm_r5, err);
 218         __get_user_error(regs->ARM_r6, &sc->arm_r6, err);
 219         __get_user_error(regs->ARM_r7, &sc->arm_r7, err);
 220         __get_user_error(regs->ARM_r8, &sc->arm_r8, err);
 221         __get_user_error(regs->ARM_r9, &sc->arm_r9, err);
 222         __get_user_error(regs->ARM_r10, &sc->arm_r10, err);
 223         __get_user_error(regs->ARM_fp, &sc->arm_fp, err);
 224         __get_user_error(regs->ARM_ip, &sc->arm_ip, err);
 225         __get_user_error(regs->ARM_sp, &sc->arm_sp, err);
 226         __get_user_error(regs->ARM_lr, &sc->arm_lr, err);
 227         __get_user_error(regs->ARM_pc, &sc->arm_pc, err);
 228         __get_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
 229
 230         err |= !valid_user_regs(regs);
 231
 232 #ifdef CONFIG_IWMMXT
 233         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 234                 err |= restore_iwmmxt_context(&aux->iwmmxt);
 235 #endif
 236 #ifdef CONFIG_VFP
 237 //      if (err == 0)
 238 //              err |= vfp_restore_state(&aux->vfp);
 239 #endif
 240
 241         return err;
 242 }
 243
 244 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 245 {
 246         struct sigframe __user *frame;
 247         sigset_t set;
 248
 249         /* Always make any pending restarted system calls return -EINTR */
 250         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 251
 252         /*
 253          * Since we stacked the signal on a 64-bit boundary,
 254          * then 'sp' should be word aligned here.  If it's
 255          * not, then the user is trying to mess with us.
 256          */
 257         if (regs->ARM_sp & 7)
 258                 goto badframe;
 259
 260         frame = (struct sigframe __user *)regs->ARM_sp;
 261
 262         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 263                 goto badframe;
 264         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 265                 goto badframe;
 266
 267         sigdelsetmask(&set, ~_BLOCKABLE);
 268         spin_lock_irq(&current->sighand->siglock);
 269         current->blocked = set;
 270         recalc_sigpending();
 271         spin_unlock_irq(&current->sighand->siglock);
 272
 273         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &frame->aux))
 274                 goto badframe;
 275
 276         /* Send SIGTRAP if we're single-stepping */
 277         if (current->ptrace & PT_SINGLESTEP) {
 278                 ptrace_cancel_bpt(current);
 279                 send_sig(SIGTRAP, current, 1);
 280         }
 281
 282         return regs->ARM_r0;
 283
 284 badframe:
 285         force_sig(SIGSEGV, current);
 286         return 0;
 287 }
 288
 289 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 290 {
 291         struct rt_sigframe __user *frame;
 292         sigset_t set;
 293
 294         /* Always make any pending restarted system calls return -EINTR */
 295         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 296
 297         /*
 298          * Since we stacked the signal on a 64-bit boundary,
 299          * then 'sp' should be word aligned here.  If it's
 300          * not, then the user is trying to mess with us.
 301          */
 302         if (regs->ARM_sp & 7)
 303                 goto badframe;
 304
 305         frame = (struct rt_sigframe __user *)regs->ARM_sp;
 306
 307         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 308                 goto badframe;
 309         if (__copy_from_user(&set, &frame->sig.uc.uc_sigmask, sizeof(set)))
 310                 goto badframe;
 311
 312         sigdelsetmask(&set, ~_BLOCKABLE);
 313         spin_lock_irq(&current->sighand->siglock);
 314         current->blocked = set;
 315         recalc_sigpending();
 316         spin_unlock_irq(&current->sighand->siglock);
 317
 318         if (restore_sigcontext(regs, &frame->sig.uc.uc_mcontext, &frame->sig.aux))
 319                 goto badframe;
 320
 321         if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
 322                 goto badframe;
 323
 324         /* Send SIGTRAP if we're single-stepping */
 325         if (current->ptrace & PT_SINGLESTEP) {
 326                 ptrace_cancel_bpt(current);
 327                 send_sig(SIGTRAP, current, 1);
 328         }
 329
 330         return regs->ARM_r0;
 331
 332 badframe:
 333         force_sig(SIGSEGV, current);
 334         return 0;
 335 }
 336
 337 static int
 338 setup_sigcontext(struct sigcontext __user *sc, struct aux_sigframe __user *aux,
 339                  struct pt_regs *regs, unsigned long mask)
 340 {
 341         int err = 0;
 342
 343         __put_user_error(regs->ARM_r0, &sc->arm_r0, err);
 344         __put_user_error(regs->ARM_r1, &sc->arm_r1, err);
 345         __put_user_error(regs->ARM_r2, &sc->arm_r2, err);
 346         __put_user_error(regs->ARM_r3, &sc->arm_r3, err);
 347         __put_user_error(regs->ARM_r4, &sc->arm_r4, err);
 348         __put_user_error(regs->ARM_r5, &sc->arm_r5, err);
 349         __put_user_error(regs->ARM_r6, &sc->arm_r6, err);
 350         __put_user_error(regs->ARM_r7, &sc->arm_r7, err);
 351         __put_user_error(regs->ARM_r8, &sc->arm_r8, err);
 352         __put_user_error(regs->ARM_r9, &sc->arm_r9, err);
 353         __put_user_error(regs->ARM_r10, &sc->arm_r10, err);
 354         __put_user_error(regs->ARM_fp, &sc->arm_fp, err);
 355         __put_user_error(regs->ARM_ip, &sc->arm_ip, err);
 356         __put_user_error(regs->ARM_sp, &sc->arm_sp, err);
 357         __put_user_error(regs->ARM_lr, &sc->arm_lr, err);
 358         __put_user_error(regs->ARM_pc, &sc->arm_pc, err);
 359         __put_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
 360
 361         __put_user_error(current->thread.trap_no, &sc->trap_no, err);
 362         __put_user_error(current->thread.error_code, &sc->error_code, err);
 363         __put_user_error(current->thread.address, &sc->fault_address, err);
 364         __put_user_error(mask, &sc->oldmask, err);
 365
 366 #ifdef CONFIG_IWMMXT
 367         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 368                 err |= preserve_iwmmxt_context(&aux->iwmmxt);
 369 #endif
 370 #ifdef CONFIG_VFP
 371 //      if (err == 0)
 372 //              err |= vfp_save_state(&aux->vfp);
 373 #endif
 374
 375         return err;
 376 }
 377
 378 static inline void __user *
 379 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 380 {
 381         unsigned long sp = regs->ARM_sp;
 382         void __user *frame;
 383
 384         /*
 385          * This is the X/Open sanctioned signal stack switching.
 386          */
 387         if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
 388                 sp = current->sas_ss_sp + current->sas_ss_size;
 389
 390         /*
 391          * ATPCS B01 mandates 8-byte alignment
 392          */
 393         frame = (void __user *)((sp - framesize) & ~7);
 394
 395         /*
 396          * Check that we can actually write to the signal frame.
 397          */
 398         if (!access_ok(VERIFY_WRITE, frame, framesize))
 399                 frame = NULL;
 400
 401         return frame;
 402 }
 403
 404 static int
 405 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 406              unsigned long __user *rc, void __user *frame, int usig)
 407 {
 408         unsigned long handler = (unsigned long)ka->sa.sa_handler;
 409         unsigned long retcode;
 410         int thumb = 0;
 411         unsigned long cpsr = regs->ARM_cpsr & ~PSR_f;
 412
 413         /*
 414          * Maybe we need to deliver a 32-bit signal to a 26-bit task.
 415          */
 416         if (ka->sa.sa_flags & SA_THIRTYTWO)
 417                 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
 418
 419 #ifdef CONFIG_ARM_THUMB
 420         if (elf_hwcap & HWCAP_THUMB) {
 421                 /*
 422                  * The LSB of the handler determines if we're going to
 423                  * be using THUMB or ARM mode for this signal handler.
 424                  */
 425                 thumb = handler & 1;
 426
 427                 if (thumb)
 428                         cpsr |= PSR_T_BIT;
 429                 else
 430                         cpsr &= ~PSR_T_BIT;
 431         }
 432 #endif
 433
 434         if (ka->sa.sa_flags & SA_RESTORER) {
 435                 retcode = (unsigned long)ka->sa.sa_restorer;
 436         } else {
 437                 unsigned int idx = thumb << 1;
 438
 439                 if (ka->sa.sa_flags & SA_SIGINFO)
 440                         idx += 3;
 441
 442                 if (__put_user(sigreturn_codes[idx],   rc) ||
 443                     __put_user(sigreturn_codes[idx+1], rc+1))
 444                         return 1;
 445
 446                 if (cpsr & MODE32_BIT) {
 447                         /*
 448                          * 32-bit code can use the new high-page
 449                          * signal return code support.
 450                          */
 451                         retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
 452                 } else {
 453                         /*
 454                          * Ensure that the instruction cache sees
 455                          * the return code written onto the stack.
 456                          */
 457                         flush_icache_range((unsigned long)rc,
 458                                            (unsigned long)(rc + 2));
 459
 460                         retcode = ((unsigned long)rc) + thumb;
 461                 }
 462         }
 463
 464         regs->ARM_r0 = usig;
 465         regs->ARM_sp = (unsigned long)frame;
 466         regs->ARM_lr = retcode;
 467         regs->ARM_pc = handler;
 468         regs->ARM_cpsr = cpsr;
 469
 470         return 0;
 471 }
 472
 473 static int
 474 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
 475 {
 476         struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 477         int err = 0;
 478
 479         if (!frame)
 480                 return 1;
 481
 482         err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->aux, regs, set->sig[0]);
 483         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 484
 485         if (err == 0)
 486                 err = setup_return(regs, ka, frame->retcode, frame, usig);
 487
 488         return err;
 489 }
 490
 491 static int
 492 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 493                sigset_t *set, struct pt_regs *regs)
 494 {
 495         struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 496         stack_t stack;
 497         int err = 0;
 498
 499         if (!frame)
 500                 return 1;
 501
 502         err |= copy_siginfo_to_user(&frame->info, info);
 503
 504         __put_user_error(0, &frame->sig.uc.uc_flags, err);
 505         __put_user_error(NULL, &frame->sig.uc.uc_link, err);
 506
 507         memset(&stack, 0, sizeof(stack));
 508         stack.ss_sp = (void __user *)current->sas_ss_sp;
 509         stack.ss_flags = sas_ss_flags(regs->ARM_sp);
 510         stack.ss_size = current->sas_ss_size;
 511         err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
 512
 513         err |= setup_sigcontext(&frame->sig.uc.uc_mcontext, &frame->sig.aux,
 514                                 regs, set->sig[0]);
 515         err |= __copy_to_user(&frame->sig.uc.uc_sigmask, set, sizeof(*set));
 516
 517         if (err == 0)
 518                 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
 519
 520         if (err == 0) {
 521                 /*
 522                  * For realtime signals we must also set the second and third
 523                  * arguments for the signal handler.
 524                  *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
 525                  */
 526                 regs->ARM_r1 = (unsigned long)&frame->info;
 527                 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
 528         }
 529
 530         return err;
 531 }
 532
 533 static inline void restart_syscall(struct pt_regs *regs)
 534 {
 535         regs->ARM_r0 = regs->ARM_ORIG_r0;
 536         regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
 537 }
 538
 539 /*
 540  * OK, we're invoking a handler
 541  */
 542 static void
 543 handle_signal(unsigned long sig, struct k_sigaction *ka,
 544               siginfo_t *info, sigset_t *oldset,
 545               struct pt_regs * regs, int syscall)
 546 {
 547         struct thread_info *thread = current_thread_info();
 548         struct task_struct *tsk = current;
 549         int usig = sig;
 550         int ret;
 551
 552         /*
 553          * If we were from a system call, check for system call restarting...
 554          */
 555         if (syscall) {
 556                 switch (regs->ARM_r0) {
 557                 case -ERESTART_RESTARTBLOCK:
 558                 case -ERESTARTNOHAND:
 559                         regs->ARM_r0 = -EINTR;
 560                         break;
 561                 case -ERESTARTSYS:
 562                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 563                                 regs->ARM_r0 = -EINTR;
 564                                 break;
 565                         }
 566                         /* fallthrough */
 567                 case -ERESTARTNOINTR:
 568                         restart_syscall(regs);
 569                 }
 570         }
 571
 572         /*
 573          * translate the signal
 574          */
 575         if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
 576                 usig = thread->exec_domain->signal_invmap[usig];
 577
 578         /*
 579          * Set up the stack frame
 580          */
 581         if (ka->sa.sa_flags & SA_SIGINFO)
 582                 ret = setup_rt_frame(usig, ka, info, oldset, regs);
 583         else
 584                 ret = setup_frame(usig, ka, oldset, regs);
 585
 586         /*
 587          * Check that the resulting registers are actually sane.
 588          */
 589         ret |= !valid_user_regs(regs);
 590
 591         if (ret != 0) {
 592                 force_sigsegv(sig, tsk);
 593                 return;
 594         }
 595
 596         /*
 597          * Block the signal if we were successful.
 598          */
 599         spin_lock_irq(&tsk->sighand->siglock);
 600         sigorsets(&tsk->blocked, &tsk->blocked,
 601                   &ka->sa.sa_mask);
 602         if (!(ka->sa.sa_flags & SA_NODEFER))
 603                 sigaddset(&tsk->blocked, sig);
 604         recalc_sigpending();
 605         spin_unlock_irq(&tsk->sighand->siglock);
 606
 607 }
 608
 609 /*
 610  * Note that 'init' is a special process: it doesn't get signals it doesn't
 611  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 612  * mistake.
 613  *
 614  * Note that we go through the signals twice: once to check the signals that
 615  * the kernel can handle, and then we build all the user-level signal handling
 616  * stack-frames in one go after that.
 617  */
 618 static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
 619 {
 620         struct k_sigaction ka;
 621         siginfo_t info;
 622         int signr;
 623
 624         /*
 625          * We want the common case to go fast, which
 626          * is why we may in certain cases get here from
 627          * kernel mode. Just return without doing anything
 628          * if so.
 629          */
 630         if (!user_mode(regs))
 631                 return 0;
 632
 633         if (try_to_freeze())
 634                 goto no_signal;
 635
 636         if (current->ptrace & PT_SINGLESTEP)
 637                 ptrace_cancel_bpt(current);
 638
 639         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 640         if (signr > 0) {
 641                 handle_signal(signr, &ka, &info, oldset, regs, syscall);
 642                 if (current->ptrace & PT_SINGLESTEP)
 643                         ptrace_set_bpt(current);
 644                 return 1;
 645         }
 646
 647  no_signal:
 648         /*
 649          * No signal to deliver to the process - restart the syscall.
 650          */
 651         if (syscall) {
 652                 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
 653                         if (thumb_mode(regs)) {
 654                                 regs->ARM_r7 = __NR_restart_syscall;
 655                                 regs->ARM_pc -= 2;
 656                         } else {
 657                                 u32 __user *usp;
 658
 659                                 regs->ARM_sp -= 12;
 660                                 usp = (u32 __user *)regs->ARM_sp;
 661
 662                                 put_user(regs->ARM_pc, &usp[0]);
 663                                 /* swi __NR_restart_syscall */
 664                                 put_user(0xef000000 | __NR_restart_syscall, &usp[1]);
 665                                 /* ldr  pc, [sp], #12 */
 666                                 put_user(0xe49df00c, &usp[2]);
 667
 668                                 flush_icache_range((unsigned long)usp,
 669                                                    (unsigned long)(usp + 3));
 670
 671                                 regs->ARM_pc = regs->ARM_sp + 4;
 672                         }
 673                 }
 674                 if (regs->ARM_r0 == -ERESTARTNOHAND ||
 675                     regs->ARM_r0 == -ERESTARTSYS ||
 676                     regs->ARM_r0 == -ERESTARTNOINTR) {
 677                         restart_syscall(regs);
 678                 }
 679         }
 680         if (current->ptrace & PT_SINGLESTEP)
 681                 ptrace_set_bpt(current);
 682         return 0;
 683 }
 684
 685 asmlinkage void
 686 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 687 {
 688         if (thread_flags & _TIF_SIGPENDING)
 689                 do_signal(&current->blocked, regs, syscall);
 690 }