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