arch/arm/kernel/signal.c

   1 /*
   2  *  linux/arch/arm/kernel/signal.c
   3  *
   4  *  Copyright (C) 1995-2002 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/errno.h>
  11 #include <linux/signal.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/personality.h>
  14
  15 #include <asm/cacheflush.h>
  16 #include <asm/ucontext.h>
  17 #include <asm/uaccess.h>
  18 #include <asm/unistd.h>
  19
  20 #include "ptrace.h"
  21 #include "signal.h"
  22
  23 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
  24
  25 /*
  26  * For ARM syscalls, we encode the syscall number into the instruction.
  27  */
  28 #define SWI_SYS_SIGRETURN       (0xef000000|(__NR_sigreturn))
  29 #define SWI_SYS_RT_SIGRETURN    (0xef000000|(__NR_rt_sigreturn))
  30
  31 /*
  32  * With EABI, the syscall number has to be loaded into r7.
  33  */
  34 #define MOV_R7_NR_SIGRETURN     (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  35 #define MOV_R7_NR_RT_SIGRETURN  (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  36
  37 /*
  38  * For Thumb syscalls, we pass the syscall number via r7.  We therefore
  39  * need two 16-bit instructions.
  40  */
  41 #define SWI_THUMB_SIGRETURN     (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  42 #define SWI_THUMB_RT_SIGRETURN  (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  43
  44 const unsigned long sigreturn_codes[7] = {
  45         MOV_R7_NR_SIGRETURN,    SWI_SYS_SIGRETURN,    SWI_THUMB_SIGRETURN,
  46         MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
  47 };
  48
  49 static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
  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, struct pt_regs *regs)
  55 {
  56         sigset_t saveset;
  57
  58         mask &= _BLOCKABLE;
  59         spin_lock_irq(&current->sighand->siglock);
  60         saveset = current->blocked;
  61         siginitset(&current->blocked, mask);
  62         recalc_sigpending();
  63         spin_unlock_irq(&current->sighand->siglock);
  64         regs->ARM_r0 = -EINTR;
  65
  66         while (1) {
  67                 current->state = TASK_INTERRUPTIBLE;
  68                 schedule();
  69                 if (do_signal(&saveset, regs, 0))
  70                         return regs->ARM_r0;
  71         }
  72 }
  73
  74 asmlinkage int
  75 sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs)
  76 {
  77         sigset_t saveset, newset;
  78
  79         /* XXX: Don't preclude handling different sized sigset_t's. */
  80         if (sigsetsize != sizeof(sigset_t))
  81                 return -EINVAL;
  82
  83         if (copy_from_user(&newset, unewset, sizeof(newset)))
  84                 return -EFAULT;
  85         sigdelsetmask(&newset, ~_BLOCKABLE);
  86
  87         spin_lock_irq(&current->sighand->siglock);
  88         saveset = current->blocked;
  89         current->blocked = newset;
  90         recalc_sigpending();
  91         spin_unlock_irq(&current->sighand->siglock);
  92         regs->ARM_r0 = -EINTR;
  93
  94         while (1) {
  95                 current->state = TASK_INTERRUPTIBLE;
  96                 schedule();
  97                 if (do_signal(&saveset, regs, 0))
  98                         return regs->ARM_r0;
  99         }
 100 }
 101
 102 asmlinkage int
 103 sys_sigaction(int sig, const struct old_sigaction __user *act,
 104               struct old_sigaction __user *oact)
 105 {
 106         struct k_sigaction new_ka, old_ka;
 107         int ret;
 108
 109         if (act) {
 110                 old_sigset_t mask;
 111                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
 112                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
 113                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
 114                         return -EFAULT;
 115                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
 116                 __get_user(mask, &act->sa_mask);
 117                 siginitset(&new_ka.sa.sa_mask, mask);
 118         }
 119
 120         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 121
 122         if (!ret && oact) {
 123                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 124                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 125                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 126                         return -EFAULT;
 127                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 128                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 129         }
 130
 131         return ret;
 132 }
 133
 134 #ifdef CONFIG_CRUNCH
 135 static int preserve_crunch_context(struct crunch_sigframe *frame)
 136 {
 137         char kbuf[sizeof(*frame) + 8];
 138         struct crunch_sigframe *kframe;
 139
 140         /* the crunch context must be 64 bit aligned */
 141         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 142         kframe->magic = CRUNCH_MAGIC;
 143         kframe->size = CRUNCH_STORAGE_SIZE;
 144         crunch_task_copy(current_thread_info(), &kframe->storage);
 145         return __copy_to_user(frame, kframe, sizeof(*frame));
 146 }
 147
 148 static int restore_crunch_context(struct crunch_sigframe *frame)
 149 {
 150         char kbuf[sizeof(*frame) + 8];
 151         struct crunch_sigframe *kframe;
 152
 153         /* the crunch context must be 64 bit aligned */
 154         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 155         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 156                 return -1;
 157         if (kframe->magic != CRUNCH_MAGIC ||
 158             kframe->size != CRUNCH_STORAGE_SIZE)
 159                 return -1;
 160         crunch_task_restore(current_thread_info(), &kframe->storage);
 161         return 0;
 162 }
 163 #endif
 164
 165 #ifdef CONFIG_IWMMXT
 166
 167 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
 168 {
 169         char kbuf[sizeof(*frame) + 8];
 170         struct iwmmxt_sigframe *kframe;
 171
 172         /* the iWMMXt context must be 64 bit aligned */
 173         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 174         kframe->magic = IWMMXT_MAGIC;
 175         kframe->size = IWMMXT_STORAGE_SIZE;
 176         iwmmxt_task_copy(current_thread_info(), &kframe->storage);
 177         return __copy_to_user(frame, kframe, sizeof(*frame));
 178 }
 179
 180 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
 181 {
 182         char kbuf[sizeof(*frame) + 8];
 183         struct iwmmxt_sigframe *kframe;
 184
 185         /* the iWMMXt context must be 64 bit aligned */
 186         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 187         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 188                 return -1;
 189         if (kframe->magic != IWMMXT_MAGIC ||
 190             kframe->size != IWMMXT_STORAGE_SIZE)
 191                 return -1;
 192         iwmmxt_task_restore(current_thread_info(), &kframe->storage);
 193         return 0;
 194 }
 195
 196 #endif
 197
 198 /*
 199  * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
 200  */
 201 struct sigframe {
 202         struct ucontext uc;
 203         unsigned long retcode[2];
 204 };
 205
 206 struct rt_sigframe {
 207         struct siginfo info;
 208         struct sigframe sig;
 209 };
 210
 211 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
 212 {
 213         struct aux_sigframe __user *aux;
 214         sigset_t set;
 215         int err;
 216
 217         err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
 218         if (err == 0) {
 219                 sigdelsetmask(&set, ~_BLOCKABLE);
 220                 spin_lock_irq(&current->sighand->siglock);
 221                 current->blocked = set;
 222                 recalc_sigpending();
 223                 spin_unlock_irq(&current->sighand->siglock);
 224         }
 225
 226         __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 227         __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 228         __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 229         __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 230         __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 231         __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 232         __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 233         __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 234         __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 235         __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 236         __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 237         __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 238         __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 239         __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 240         __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 241         __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 242         __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 243
 244         err |= !valid_user_regs(regs);
 245
 246         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 247 #ifdef CONFIG_CRUNCH
 248         if (err == 0)
 249                 err |= restore_crunch_context(&aux->crunch);
 250 #endif
 251 #ifdef CONFIG_IWMMXT
 252         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 253                 err |= restore_iwmmxt_context(&aux->iwmmxt);
 254 #endif
 255 #ifdef CONFIG_VFP
 256 //      if (err == 0)
 257 //              err |= vfp_restore_state(&sf->aux.vfp);
 258 #endif
 259
 260         return err;
 261 }
 262
 263 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 264 {
 265         struct sigframe __user *frame;
 266
 267         /* Always make any pending restarted system calls return -EINTR */
 268         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 269
 270         /*
 271          * Since we stacked the signal on a 64-bit boundary,
 272          * then 'sp' should be word aligned here.  If it's
 273          * not, then the user is trying to mess with us.
 274          */
 275         if (regs->ARM_sp & 7)
 276                 goto badframe;
 277
 278         frame = (struct sigframe __user *)regs->ARM_sp;
 279
 280         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 281                 goto badframe;
 282
 283         if (restore_sigframe(regs, frame))
 284                 goto badframe;
 285
 286         /* Send SIGTRAP if we're single-stepping */
 287         if (current->ptrace & PT_SINGLESTEP) {
 288                 ptrace_cancel_bpt(current);
 289                 send_sig(SIGTRAP, current, 1);
 290         }
 291
 292         return regs->ARM_r0;
 293
 294 badframe:
 295         force_sig(SIGSEGV, current);
 296         return 0;
 297 }
 298
 299 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 300 {
 301         struct rt_sigframe __user *frame;
 302
 303         /* Always make any pending restarted system calls return -EINTR */
 304         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 305
 306         /*
 307          * Since we stacked the signal on a 64-bit boundary,
 308          * then 'sp' should be word aligned here.  If it's
 309          * not, then the user is trying to mess with us.
 310          */
 311         if (regs->ARM_sp & 7)
 312                 goto badframe;
 313
 314         frame = (struct rt_sigframe __user *)regs->ARM_sp;
 315
 316         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 317                 goto badframe;
 318
 319         if (restore_sigframe(regs, &frame->sig))
 320                 goto badframe;
 321
 322         if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
 323                 goto badframe;
 324
 325         /* Send SIGTRAP if we're single-stepping */
 326         if (current->ptrace & PT_SINGLESTEP) {
 327                 ptrace_cancel_bpt(current);
 328                 send_sig(SIGTRAP, current, 1);
 329         }
 330
 331         return regs->ARM_r0;
 332
 333 badframe:
 334         force_sig(SIGSEGV, current);
 335         return 0;
 336 }
 337
 338 static int
 339 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 340 {
 341         struct aux_sigframe __user *aux;
 342         int err = 0;
 343
 344         __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 345         __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 346         __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 347         __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 348         __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 349         __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 350         __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 351         __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 352         __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 353         __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 354         __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 355         __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 356         __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 357         __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 358         __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 359         __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 360         __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 361
 362         __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
 363         __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
 364         __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
 365         __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
 366
 367         err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
 368
 369         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 370 #ifdef CONFIG_CRUNCH
 371         if (err == 0)
 372                 err |= preserve_crunch_context(&aux->crunch);
 373 #endif
 374 #ifdef CONFIG_IWMMXT
 375         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 376                 err |= preserve_iwmmxt_context(&aux->iwmmxt);
 377 #endif
 378 #ifdef CONFIG_VFP
 379 //      if (err == 0)
 380 //              err |= vfp_save_state(&sf->aux.vfp);
 381 #endif
 382         __put_user_error(0, &aux->end_magic, err);
 383
 384         return err;
 385 }
 386
 387 static inline void __user *
 388 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 389 {
 390         unsigned long sp = regs->ARM_sp;
 391         void __user *frame;
 392
 393         /*
 394          * This is the X/Open sanctioned signal stack switching.
 395          */
 396         if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
 397                 sp = current->sas_ss_sp + current->sas_ss_size;
 398
 399         /*
 400          * ATPCS B01 mandates 8-byte alignment
 401          */
 402         frame = (void __user *)((sp - framesize) & ~7);
 403
 404         /*
 405          * Check that we can actually write to the signal frame.
 406          */
 407         if (!access_ok(VERIFY_WRITE, frame, framesize))
 408                 frame = NULL;
 409
 410         return frame;
 411 }
 412
 413 static int
 414 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 415              unsigned long __user *rc, void __user *frame, int usig)
 416 {
 417         unsigned long handler = (unsigned long)ka->sa.sa_handler;
 418         unsigned long retcode;
 419         int thumb = 0;
 420         unsigned long cpsr = regs->ARM_cpsr & ~PSR_f;
 421
 422         /*
 423          * Maybe we need to deliver a 32-bit signal to a 26-bit task.
 424          */
 425         if (ka->sa.sa_flags & SA_THIRTYTWO)
 426                 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
 427
 428 #ifdef CONFIG_ARM_THUMB
 429         if (elf_hwcap & HWCAP_THUMB) {
 430                 /*
 431                  * The LSB of the handler determines if we're going to
 432                  * be using THUMB or ARM mode for this signal handler.
 433                  */
 434                 thumb = handler & 1;
 435
 436                 if (thumb)
 437                         cpsr |= PSR_T_BIT;
 438                 else
 439                         cpsr &= ~PSR_T_BIT;
 440         }
 441 #endif
 442
 443         if (ka->sa.sa_flags & SA_RESTORER) {
 444                 retcode = (unsigned long)ka->sa.sa_restorer;
 445         } else {
 446                 unsigned int idx = thumb << 1;
 447
 448                 if (ka->sa.sa_flags & SA_SIGINFO)
 449                         idx += 3;
 450
 451                 if (__put_user(sigreturn_codes[idx],   rc) ||
 452                     __put_user(sigreturn_codes[idx+1], rc+1))
 453                         return 1;
 454
 455                 if (cpsr & MODE32_BIT) {
 456                         /*
 457                          * 32-bit code can use the new high-page
 458                          * signal return code support.
 459                          */
 460                         retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
 461                 } else {
 462                         /*
 463                          * Ensure that the instruction cache sees
 464                          * the return code written onto the stack.
 465                          */
 466                         flush_icache_range((unsigned long)rc,
 467                                            (unsigned long)(rc + 2));
 468
 469                         retcode = ((unsigned long)rc) + thumb;
 470                 }
 471         }
 472
 473         regs->ARM_r0 = usig;
 474         regs->ARM_sp = (unsigned long)frame;
 475         regs->ARM_lr = retcode;
 476         regs->ARM_pc = handler;
 477         regs->ARM_cpsr = cpsr;
 478
 479         return 0;
 480 }
 481
 482 static int
 483 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
 484 {
 485         struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 486         int err = 0;
 487
 488         if (!frame)
 489                 return 1;
 490
 491         /*
 492          * Set uc.uc_flags to a value which sc.trap_no would never have.
 493          */
 494         __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
 495
 496         err |= setup_sigframe(frame, regs, set);
 497         if (err == 0)
 498                 err = setup_return(regs, ka, frame->retcode, frame, usig);
 499
 500         return err;
 501 }
 502
 503 static int
 504 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 505                sigset_t *set, struct pt_regs *regs)
 506 {
 507         struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 508         stack_t stack;
 509         int err = 0;
 510
 511         if (!frame)
 512                 return 1;
 513
 514         err |= copy_siginfo_to_user(&frame->info, info);
 515
 516         __put_user_error(0, &frame->sig.uc.uc_flags, err);
 517         __put_user_error(NULL, &frame->sig.uc.uc_link, err);
 518
 519         memset(&stack, 0, sizeof(stack));
 520         stack.ss_sp = (void __user *)current->sas_ss_sp;
 521         stack.ss_flags = sas_ss_flags(regs->ARM_sp);
 522         stack.ss_size = current->sas_ss_size;
 523         err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
 524
 525         err |= setup_sigframe(&frame->sig, regs, set);
 526         if (err == 0)
 527                 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
 528
 529         if (err == 0) {
 530                 /*
 531                  * For realtime signals we must also set the second and third
 532                  * arguments for the signal handler.
 533                  *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
 534                  */
 535                 regs->ARM_r1 = (unsigned long)&frame->info;
 536                 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
 537         }
 538
 539         return err;
 540 }
 541
 542 static inline void restart_syscall(struct pt_regs *regs)
 543 {
 544         regs->ARM_r0 = regs->ARM_ORIG_r0;
 545         regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
 546 }
 547
 548 /*
 549  * OK, we're invoking a handler
 550  */
 551 static void
 552 handle_signal(unsigned long sig, struct k_sigaction *ka,
 553               siginfo_t *info, sigset_t *oldset,
 554               struct pt_regs * regs, int syscall)
 555 {
 556         struct thread_info *thread = current_thread_info();
 557         struct task_struct *tsk = current;
 558         int usig = sig;
 559         int ret;
 560
 561         /*
 562          * If we were from a system call, check for system call restarting...
 563          */
 564         if (syscall) {
 565                 switch (regs->ARM_r0) {
 566                 case -ERESTART_RESTARTBLOCK:
 567                 case -ERESTARTNOHAND:
 568                         regs->ARM_r0 = -EINTR;
 569                         break;
 570                 case -ERESTARTSYS:
 571                         if (!(ka->sa.sa_flags & SA_RESTART)) {
 572                                 regs->ARM_r0 = -EINTR;
 573                                 break;
 574                         }
 575                         /* fallthrough */
 576                 case -ERESTARTNOINTR:
 577                         restart_syscall(regs);
 578                 }
 579         }
 580
 581         /*
 582          * translate the signal
 583          */
 584         if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
 585                 usig = thread->exec_domain->signal_invmap[usig];
 586
 587         /*
 588          * Set up the stack frame
 589          */
 590         if (ka->sa.sa_flags & SA_SIGINFO)
 591                 ret = setup_rt_frame(usig, ka, info, oldset, regs);
 592         else
 593                 ret = setup_frame(usig, ka, oldset, regs);
 594
 595         /*
 596          * Check that the resulting registers are actually sane.
 597          */
 598         ret |= !valid_user_regs(regs);
 599
 600         if (ret != 0) {
 601                 force_sigsegv(sig, tsk);
 602                 return;
 603         }
 604
 605         /*
 606          * Block the signal if we were successful.
 607          */
 608         spin_lock_irq(&tsk->sighand->siglock);
 609         sigorsets(&tsk->blocked, &tsk->blocked,
 610                   &ka->sa.sa_mask);
 611         if (!(ka->sa.sa_flags & SA_NODEFER))
 612                 sigaddset(&tsk->blocked, sig);
 613         recalc_sigpending();
 614         spin_unlock_irq(&tsk->sighand->siglock);
 615
 616 }
 617
 618 /*
 619  * Note that 'init' is a special process: it doesn't get signals it doesn't
 620  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 621  * mistake.
 622  *
 623  * Note that we go through the signals twice: once to check the signals that
 624  * the kernel can handle, and then we build all the user-level signal handling
 625  * stack-frames in one go after that.
 626  */
 627 static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
 628 {
 629         struct k_sigaction ka;
 630         siginfo_t info;
 631         int signr;
 632
 633         /*
 634          * We want the common case to go fast, which
 635          * is why we may in certain cases get here from
 636          * kernel mode. Just return without doing anything
 637          * if so.
 638          */
 639         if (!user_mode(regs))
 640                 return 0;
 641
 642         if (try_to_freeze())
 643                 goto no_signal;
 644
 645         if (current->ptrace & PT_SINGLESTEP)
 646                 ptrace_cancel_bpt(current);
 647
 648         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 649         if (signr > 0) {
 650                 handle_signal(signr, &ka, &info, oldset, regs, syscall);
 651                 if (current->ptrace & PT_SINGLESTEP)
 652                         ptrace_set_bpt(current);
 653                 return 1;
 654         }
 655
 656  no_signal:
 657         /*
 658          * No signal to deliver to the process - restart the syscall.
 659          */
 660         if (syscall) {
 661                 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
 662                         if (thumb_mode(regs)) {
 663                                 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
 664                                 regs->ARM_pc -= 2;
 665                         } else {
 666 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
 667                                 regs->ARM_r7 = __NR_restart_syscall;
 668                                 regs->ARM_pc -= 4;
 669 #else
 670                                 u32 __user *usp;
 671                                 u32 swival = __NR_restart_syscall;
 672
 673                                 regs->ARM_sp -= 12;
 674                                 usp = (u32 __user *)regs->ARM_sp;
 675
 676                                 /*
 677                                  * Either we supports OABI only, or we have
 678                                  * EABI with the OABI compat layer enabled.
 679                                  * In the later case we don't know if user
 680                                  * space is EABI or not, and if not we must
 681                                  * not clobber r7.  Always using the OABI
 682                                  * syscall solves that issue and works for
 683                                  * all those cases.
 684                                  */
 685                                 swival = swival - __NR_SYSCALL_BASE + __NR_OABI_SYSCALL_BASE;
 686
 687                                 put_user(regs->ARM_pc, &usp[0]);
 688                                 /* swi __NR_restart_syscall */
 689                                 put_user(0xef000000 | swival, &usp[1]);
 690                                 /* ldr  pc, [sp], #12 */
 691                                 put_user(0xe49df00c, &usp[2]);
 692
 693                                 flush_icache_range((unsigned long)usp,
 694                                                    (unsigned long)(usp + 3));
 695
 696                                 regs->ARM_pc = regs->ARM_sp + 4;
 697 #endif
 698                         }
 699                 }
 700                 if (regs->ARM_r0 == -ERESTARTNOHAND ||
 701                     regs->ARM_r0 == -ERESTARTSYS ||
 702                     regs->ARM_r0 == -ERESTARTNOINTR) {
 703                         restart_syscall(regs);
 704                 }
 705         }
 706         if (current->ptrace & PT_SINGLESTEP)
 707                 ptrace_set_bpt(current);
 708         return 0;
 709 }
 710
 711 asmlinkage void
 712 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 713 {
 714         if (thread_flags & _TIF_SIGPENDING)
 715                 do_signal(&current->blocked, regs, syscall);
 716 }