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
  15 #include <asm/elf.h>
  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_CRUNCH
 136 static int preserve_crunch_context(struct crunch_sigframe *frame)
 137 {
 138         char kbuf[sizeof(*frame) + 8];
 139         struct crunch_sigframe *kframe;
 140
 141         /* the crunch context must be 64 bit aligned */
 142         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 143         kframe->magic = CRUNCH_MAGIC;
 144         kframe->size = CRUNCH_STORAGE_SIZE;
 145         crunch_task_copy(current_thread_info(), &kframe->storage);
 146         return __copy_to_user(frame, kframe, sizeof(*frame));
 147 }
 148
 149 static int restore_crunch_context(struct crunch_sigframe *frame)
 150 {
 151         char kbuf[sizeof(*frame) + 8];
 152         struct crunch_sigframe *kframe;
 153
 154         /* the crunch context must be 64 bit aligned */
 155         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 156         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 157                 return -1;
 158         if (kframe->magic != CRUNCH_MAGIC ||
 159             kframe->size != CRUNCH_STORAGE_SIZE)
 160                 return -1;
 161         crunch_task_restore(current_thread_info(), &kframe->storage);
 162         return 0;
 163 }
 164 #endif
 165
 166 #ifdef CONFIG_IWMMXT
 167
 168 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
 169 {
 170         char kbuf[sizeof(*frame) + 8];
 171         struct iwmmxt_sigframe *kframe;
 172
 173         /* the iWMMXt context must be 64 bit aligned */
 174         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 175         kframe->magic = IWMMXT_MAGIC;
 176         kframe->size = IWMMXT_STORAGE_SIZE;
 177         iwmmxt_task_copy(current_thread_info(), &kframe->storage);
 178         return __copy_to_user(frame, kframe, sizeof(*frame));
 179 }
 180
 181 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
 182 {
 183         char kbuf[sizeof(*frame) + 8];
 184         struct iwmmxt_sigframe *kframe;
 185
 186         /* the iWMMXt context must be 64 bit aligned */
 187         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 188         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 189                 return -1;
 190         if (kframe->magic != IWMMXT_MAGIC ||
 191             kframe->size != IWMMXT_STORAGE_SIZE)
 192                 return -1;
 193         iwmmxt_task_restore(current_thread_info(), &kframe->storage);
 194         return 0;
 195 }
 196
 197 #endif
 198
 199 /*
 200  * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
 201  */
 202 struct sigframe {
 203         struct ucontext uc;
 204         unsigned long retcode[2];
 205 };
 206
 207 struct rt_sigframe {
 208         struct siginfo info;
 209         struct sigframe sig;
 210 };
 211
 212 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
 213 {
 214         struct aux_sigframe __user *aux;
 215         sigset_t set;
 216         int err;
 217
 218         err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
 219         if (err == 0) {
 220                 sigdelsetmask(&set, ~_BLOCKABLE);
 221                 spin_lock_irq(&current->sighand->siglock);
 222                 current->blocked = set;
 223                 recalc_sigpending();
 224                 spin_unlock_irq(&current->sighand->siglock);
 225         }
 226
 227         __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 228         __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 229         __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 230         __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 231         __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 232         __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 233         __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 234         __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 235         __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 236         __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 237         __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 238         __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 239         __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 240         __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 241         __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 242         __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 243         __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 244
 245         err |= !valid_user_regs(regs);
 246
 247         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 248 #ifdef CONFIG_CRUNCH
 249         if (err == 0)
 250                 err |= restore_crunch_context(&aux->crunch);
 251 #endif
 252 #ifdef CONFIG_IWMMXT
 253         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 254                 err |= restore_iwmmxt_context(&aux->iwmmxt);
 255 #endif
 256 #ifdef CONFIG_VFP
 257 //      if (err == 0)
 258 //              err |= vfp_restore_state(&sf->aux.vfp);
 259 #endif
 260
 261         return err;
 262 }
 263
 264 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 265 {
 266         struct sigframe __user *frame;
 267
 268         /* Always make any pending restarted system calls return -EINTR */
 269         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 270
 271         /*
 272          * Since we stacked the signal on a 64-bit boundary,
 273          * then 'sp' should be word aligned here.  If it's
 274          * not, then the user is trying to mess with us.
 275          */
 276         if (regs->ARM_sp & 7)
 277                 goto badframe;
 278
 279         frame = (struct sigframe __user *)regs->ARM_sp;
 280
 281         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 282                 goto badframe;
 283
 284         if (restore_sigframe(regs, frame))
 285                 goto badframe;
 286
 287         single_step_trap(current);
 288
 289         return regs->ARM_r0;
 290
 291 badframe:
 292         force_sig(SIGSEGV, current);
 293         return 0;
 294 }
 295
 296 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 297 {
 298         struct rt_sigframe __user *frame;
 299
 300         /* Always make any pending restarted system calls return -EINTR */
 301         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 302
 303         /*
 304          * Since we stacked the signal on a 64-bit boundary,
 305          * then 'sp' should be word aligned here.  If it's
 306          * not, then the user is trying to mess with us.
 307          */
 308         if (regs->ARM_sp & 7)
 309                 goto badframe;
 310
 311         frame = (struct rt_sigframe __user *)regs->ARM_sp;
 312
 313         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 314                 goto badframe;
 315
 316         if (restore_sigframe(regs, &frame->sig))
 317                 goto badframe;
 318
 319         if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
 320                 goto badframe;
 321
 322         single_step_trap(current);
 323
 324         return regs->ARM_r0;
 325
 326 badframe:
 327         force_sig(SIGSEGV, current);
 328         return 0;
 329 }
 330
 331 static int
 332 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 333 {
 334         struct aux_sigframe __user *aux;
 335         int err = 0;
 336
 337         __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 338         __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 339         __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 340         __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 341         __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 342         __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 343         __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 344         __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 345         __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 346         __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 347         __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 348         __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 349         __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 350         __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 351         __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 352         __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 353         __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 354
 355         __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
 356         __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
 357         __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
 358         __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
 359
 360         err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
 361
 362         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 363 #ifdef CONFIG_CRUNCH
 364         if (err == 0)
 365                 err |= preserve_crunch_context(&aux->crunch);
 366 #endif
 367 #ifdef CONFIG_IWMMXT
 368         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 369                 err |= preserve_iwmmxt_context(&aux->iwmmxt);
 370 #endif
 371 #ifdef CONFIG_VFP
 372 //      if (err == 0)
 373 //              err |= vfp_save_state(&sf->aux.vfp);
 374 #endif
 375         __put_user_error(0, &aux->end_magic, err);
 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 << 1;
 440
 441                 if (ka->sa.sa_flags & SA_SIGINFO)
 442                         idx += 3;
 443
 444                 if (__put_user(sigreturn_codes[idx],   rc) ||
 445                     __put_user(sigreturn_codes[idx+1], rc+1))
 446                         return 1;
 447
 448                 if (cpsr & MODE32_BIT) {
 449                         /*
 450                          * 32-bit code can use the new high-page
 451                          * signal return code support.
 452                          */
 453                         retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
 454                 } else {
 455                         /*
 456                          * Ensure that the instruction cache sees
 457                          * the return code written onto the stack.
 458                          */
 459                         flush_icache_range((unsigned long)rc,
 460                                            (unsigned long)(rc + 2));
 461
 462                         retcode = ((unsigned long)rc) + thumb;
 463                 }
 464         }
 465
 466         regs->ARM_r0 = usig;
 467         regs->ARM_sp = (unsigned long)frame;
 468         regs->ARM_lr = retcode;
 469         regs->ARM_pc = handler;
 470         regs->ARM_cpsr = cpsr;
 471
 472         return 0;
 473 }
 474
 475 static int
 476 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
 477 {
 478         struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 479         int err = 0;
 480
 481         if (!frame)
 482                 return 1;
 483
 484         /*
 485          * Set uc.uc_flags to a value which sc.trap_no would never have.
 486          */
 487         __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
 488
 489         err |= setup_sigframe(frame, regs, set);
 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         err |= copy_siginfo_to_user(&frame->info, info);
 508
 509         __put_user_error(0, &frame->sig.uc.uc_flags, err);
 510         __put_user_error(NULL, &frame->sig.uc.uc_link, err);
 511
 512         memset(&stack, 0, sizeof(stack));
 513         stack.ss_sp = (void __user *)current->sas_ss_sp;
 514         stack.ss_flags = sas_ss_flags(regs->ARM_sp);
 515         stack.ss_size = current->sas_ss_size;
 516         err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
 517
 518         err |= setup_sigframe(&frame->sig, regs, set);
 519         if (err == 0)
 520                 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
 521
 522         if (err == 0) {
 523                 /*
 524                  * For realtime signals we must also set the second and third
 525                  * arguments for the signal handler.
 526                  *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
 527                  */
 528                 regs->ARM_r1 = (unsigned long)&frame->info;
 529                 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
 530         }
 531
 532         return err;
 533 }
 534
 535 static inline void restart_syscall(struct pt_regs *regs)
 536 {
 537         regs->ARM_r0 = regs->ARM_ORIG_r0;
 538         regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
 539 }
 540
 541 /*
 542  * OK, we're invoking a handler
 543  */
 544 static void
 545 handle_signal(unsigned long sig, struct k_sigaction *ka,
 546               siginfo_t *info, sigset_t *oldset,
 547               struct pt_regs * regs, int syscall)
 548 {
 549         struct thread_info *thread = current_thread_info();
 550         struct task_struct *tsk = current;
 551         int usig = sig;
 552         int ret;
 553
 554         /*
 555          * If we were from a system call, check for system call restarting...
 556          */
 557         if (syscall) {
 558                 switch (regs->ARM_r0) {
 559                 case -ERESTART_RESTARTBLOCK:
 560                 case -ERESTARTNOHAND:
 561                         regs->ARM_r0 = -EINTR;
 562                         break;
 563                 case -ERESTARTSYS:
 564                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 565                                 regs->ARM_r0 = -EINTR;
 566                                 break;
 567                         }
 568                         /* fallthrough */
 569                 case -ERESTARTNOINTR:
 570                         restart_syscall(regs);
 571                 }
 572         }
 573
 574         /*
 575          * translate the signal
 576          */
 577         if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
 578                 usig = thread->exec_domain->signal_invmap[usig];
 579
 580         /*
 581          * Set up the stack frame
 582          */
 583         if (ka->sa.sa_flags & SA_SIGINFO)
 584                 ret = setup_rt_frame(usig, ka, info, oldset, regs);
 585         else
 586                 ret = setup_frame(usig, ka, oldset, regs);
 587
 588         /*
 589          * Check that the resulting registers are actually sane.
 590          */
 591         ret |= !valid_user_regs(regs);
 592
 593         if (ret != 0) {
 594                 force_sigsegv(sig, tsk);
 595                 return;
 596         }
 597
 598         /*
 599          * Block the signal if we were successful.
 600          */
 601         spin_lock_irq(&tsk->sighand->siglock);
 602         sigorsets(&tsk->blocked, &tsk->blocked,
 603                   &ka->sa.sa_mask);
 604         if (!(ka->sa.sa_flags & SA_NODEFER))
 605                 sigaddset(&tsk->blocked, sig);
 606         recalc_sigpending();
 607         spin_unlock_irq(&tsk->sighand->siglock);
 608
 609 }
 610
 611 /*
 612  * Note that 'init' is a special process: it doesn't get signals it doesn't
 613  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 614  * mistake.
 615  *
 616  * Note that we go through the signals twice: once to check the signals that
 617  * the kernel can handle, and then we build all the user-level signal handling
 618  * stack-frames in one go after that.
 619  */
 620 static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
 621 {
 622         struct k_sigaction ka;
 623         siginfo_t info;
 624         int signr;
 625
 626         /*
 627          * We want the common case to go fast, which
 628          * is why we may in certain cases get here from
 629          * kernel mode. Just return without doing anything
 630          * if so.
 631          */
 632         if (!user_mode(regs))
 633                 return 0;
 634
 635         if (try_to_freeze())
 636                 goto no_signal;
 637
 638         single_step_clear(current);
 639
 640         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 641         if (signr > 0) {
 642                 handle_signal(signr, &ka, &info, oldset, regs, syscall);
 643                 single_step_set(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 - __NR_SYSCALL_BASE;
 655                                 regs->ARM_pc -= 2;
 656                         } else {
 657 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
 658                                 regs->ARM_r7 = __NR_restart_syscall;
 659                                 regs->ARM_pc -= 4;
 660 #else
 661                                 u32 __user *usp;
 662                                 u32 swival = __NR_restart_syscall;
 663
 664                                 regs->ARM_sp -= 12;
 665                                 usp = (u32 __user *)regs->ARM_sp;
 666
 667                                 /*
 668                                  * Either we supports OABI only, or we have
 669                                  * EABI with the OABI compat layer enabled.
 670                                  * In the later case we don't know if user
 671                                  * space is EABI or not, and if not we must
 672                                  * not clobber r7.  Always using the OABI
 673                                  * syscall solves that issue and works for
 674                                  * all those cases.
 675                                  */
 676                                 swival = swival - __NR_SYSCALL_BASE + __NR_OABI_SYSCALL_BASE;
 677
 678                                 put_user(regs->ARM_pc, &usp[0]);
 679                                 /* swi __NR_restart_syscall */
 680                                 put_user(0xef000000 | swival, &usp[1]);
 681                                 /* ldr  pc, [sp], #12 */
 682                                 put_user(0xe49df00c, &usp[2]);
 683
 684                                 flush_icache_range((unsigned long)usp,
 685                                                    (unsigned long)(usp + 3));
 686
 687                                 regs->ARM_pc = regs->ARM_sp + 4;
 688 #endif
 689                         }
 690                 }
 691                 if (regs->ARM_r0 == -ERESTARTNOHAND ||
 692                     regs->ARM_r0 == -ERESTARTSYS ||
 693                     regs->ARM_r0 == -ERESTARTNOINTR) {
 694                         restart_syscall(regs);
 695                 }
 696         }
 697         single_step_set(current);
 698         return 0;
 699 }
 700
 701 asmlinkage void
 702 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 703 {
 704         if (thread_flags & _TIF_SIGPENDING)
 705                 do_signal(&current->blocked, regs, syscall);
 706 }