arch/arm/kernel/signal.c

   1 /*
   2  *  linux/arch/arm/kernel/signal.c
   3  *
   4  *  Copyright (C) 1995-2009 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 #include <asm/vfp.h>
  22
  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 #define SWI_SYS_RESTART         (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
  33
  34 /*
  35  * With EABI, the syscall number has to be loaded into r7.
  36  */
  37 #define MOV_R7_NR_SIGRETURN     (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  38 #define MOV_R7_NR_RT_SIGRETURN  (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  39
  40 /*
  41  * For Thumb syscalls, we pass the syscall number via r7.  We therefore
  42  * need two 16-bit instructions.
  43  */
  44 #define SWI_THUMB_SIGRETURN     (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
  45 #define SWI_THUMB_RT_SIGRETURN  (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
  46
  47 const unsigned long sigreturn_codes[7] = {
  48         MOV_R7_NR_SIGRETURN,    SWI_SYS_SIGRETURN,    SWI_THUMB_SIGRETURN,
  49         MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
  50 };
  51
  52 /*
  53  * Either we support OABI only, or we have EABI with the OABI
  54  * compat layer enabled.  In the later case we don't know if
  55  * user space is EABI or not, and if not we must not clobber r7.
  56  * Always using the OABI syscall solves that issue and works for
  57  * all those cases.
  58  */
  59 const unsigned long syscall_restart_code[2] = {
  60         SWI_SYS_RESTART,        /* swi  __NR_restart_syscall */
  61         0xe49df004,             /* ldr  pc, [sp], #4 */
  62 };
  63
  64 /*
  65  * atomically swap in the new signal mask, and wait for a signal.
  66  */
  67 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
  68 {
  69         sigset_t blocked;
  70
  71         current->saved_sigmask = current->blocked;
  72
  73         mask &= _BLOCKABLE;
  74         siginitset(&blocked, mask);
  75         set_current_blocked(&blocked);
  76
  77         current->state = TASK_INTERRUPTIBLE;
  78         schedule();
  79         set_restore_sigmask();
  80         return -ERESTARTNOHAND;
  81 }
  82
  83 asmlinkage int
  84 sys_sigaction(int sig, const struct old_sigaction __user *act,
  85               struct old_sigaction __user *oact)
  86 {
  87         struct k_sigaction new_ka, old_ka;
  88         int ret;
  89
  90         if (act) {
  91                 old_sigset_t mask;
  92                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  93                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  94                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  95                         return -EFAULT;
  96                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  97                 __get_user(mask, &act->sa_mask);
  98                 siginitset(&new_ka.sa.sa_mask, mask);
  99         }
 100
 101         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 102
 103         if (!ret && oact) {
 104                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 105                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 106                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 107                         return -EFAULT;
 108                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 109                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 110         }
 111
 112         return ret;
 113 }
 114
 115 #ifdef CONFIG_CRUNCH
 116 static int preserve_crunch_context(struct crunch_sigframe __user *frame)
 117 {
 118         char kbuf[sizeof(*frame) + 8];
 119         struct crunch_sigframe *kframe;
 120
 121         /* the crunch context must be 64 bit aligned */
 122         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 123         kframe->magic = CRUNCH_MAGIC;
 124         kframe->size = CRUNCH_STORAGE_SIZE;
 125         crunch_task_copy(current_thread_info(), &kframe->storage);
 126         return __copy_to_user(frame, kframe, sizeof(*frame));
 127 }
 128
 129 static int restore_crunch_context(struct crunch_sigframe __user *frame)
 130 {
 131         char kbuf[sizeof(*frame) + 8];
 132         struct crunch_sigframe *kframe;
 133
 134         /* the crunch context must be 64 bit aligned */
 135         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 136         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 137                 return -1;
 138         if (kframe->magic != CRUNCH_MAGIC ||
 139             kframe->size != CRUNCH_STORAGE_SIZE)
 140                 return -1;
 141         crunch_task_restore(current_thread_info(), &kframe->storage);
 142         return 0;
 143 }
 144 #endif
 145
 146 #ifdef CONFIG_IWMMXT
 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->magic = IWMMXT_MAGIC;
 156         kframe->size = IWMMXT_STORAGE_SIZE;
 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->magic != IWMMXT_MAGIC ||
 171             kframe->size != IWMMXT_STORAGE_SIZE)
 172                 return -1;
 173         iwmmxt_task_restore(current_thread_info(), &kframe->storage);
 174         return 0;
 175 }
 176
 177 #endif
 178
 179 #ifdef CONFIG_VFP
 180
 181 static int preserve_vfp_context(struct vfp_sigframe __user *frame)
 182 {
 183         struct thread_info *thread = current_thread_info();
 184         struct vfp_hard_struct *h = &thread->vfpstate.hard;
 185         const unsigned long magic = VFP_MAGIC;
 186         const unsigned long size = VFP_STORAGE_SIZE;
 187         int err = 0;
 188
 189         vfp_sync_hwstate(thread);
 190         __put_user_error(magic, &frame->magic, err);
 191         __put_user_error(size, &frame->size, err);
 192
 193         /*
 194          * Copy the floating point registers. There can be unused
 195          * registers see asm/hwcap.h for details.
 196          */
 197         err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs,
 198                               sizeof(h->fpregs));
 199         /*
 200          * Copy the status and control register.
 201          */
 202         __put_user_error(h->fpscr, &frame->ufp.fpscr, err);
 203
 204         /*
 205          * Copy the exception registers.
 206          */
 207         __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err);
 208         __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
 209         __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
 210
 211         return err ? -EFAULT : 0;
 212 }
 213
 214 static int restore_vfp_context(struct vfp_sigframe __user *frame)
 215 {
 216         struct thread_info *thread = current_thread_info();
 217         struct vfp_hard_struct *h = &thread->vfpstate.hard;
 218         unsigned long magic;
 219         unsigned long size;
 220         unsigned long fpexc;
 221         int err = 0;
 222
 223         __get_user_error(magic, &frame->magic, err);
 224         __get_user_error(size, &frame->size, err);
 225
 226         if (err)
 227                 return -EFAULT;
 228         if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
 229                 return -EINVAL;
 230
 231         vfp_flush_hwstate(thread);
 232
 233         /*
 234          * Copy the floating point registers. There can be unused
 235          * registers see asm/hwcap.h for details.
 236          */
 237         err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs,
 238                                 sizeof(h->fpregs));
 239         /*
 240          * Copy the status and control register.
 241          */
 242         __get_user_error(h->fpscr, &frame->ufp.fpscr, err);
 243
 244         /*
 245          * Sanitise and restore the exception registers.
 246          */
 247         __get_user_error(fpexc, &frame->ufp_exc.fpexc, err);
 248         /* Ensure the VFP is enabled. */
 249         fpexc |= FPEXC_EN;
 250         /* Ensure FPINST2 is invalid and the exception flag is cleared. */
 251         fpexc &= ~(FPEXC_EX | FPEXC_FP2V);
 252         h->fpexc = fpexc;
 253
 254         __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
 255         __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
 256
 257         return err ? -EFAULT : 0;
 258 }
 259
 260 #endif
 261
 262 /*
 263  * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
 264  */
 265 struct sigframe {
 266         struct ucontext uc;
 267         unsigned long retcode[2];
 268 };
 269
 270 struct rt_sigframe {
 271         struct siginfo info;
 272         struct sigframe sig;
 273 };
 274
 275 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
 276 {
 277         struct aux_sigframe __user *aux;
 278         sigset_t set;
 279         int err;
 280
 281         err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
 282         if (err == 0) {
 283                 sigdelsetmask(&set, ~_BLOCKABLE);
 284                 set_current_blocked(&set);
 285         }
 286
 287         __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 288         __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 289         __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 290         __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 291         __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 292         __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 293         __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 294         __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 295         __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 296         __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 297         __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 298         __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 299         __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 300         __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 301         __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 302         __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 303         __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 304
 305         err |= !valid_user_regs(regs);
 306
 307         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 308 #ifdef CONFIG_CRUNCH
 309         if (err == 0)
 310                 err |= restore_crunch_context(&aux->crunch);
 311 #endif
 312 #ifdef CONFIG_IWMMXT
 313         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 314                 err |= restore_iwmmxt_context(&aux->iwmmxt);
 315 #endif
 316 #ifdef CONFIG_VFP
 317         if (err == 0)
 318                 err |= restore_vfp_context(&aux->vfp);
 319 #endif
 320
 321         return err;
 322 }
 323
 324 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 325 {
 326         struct sigframe __user *frame;
 327
 328         /* Always make any pending restarted system calls return -EINTR */
 329         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 330
 331         /*
 332          * Since we stacked the signal on a 64-bit boundary,
 333          * then 'sp' should be word aligned here.  If it's
 334          * not, then the user is trying to mess with us.
 335          */
 336         if (regs->ARM_sp & 7)
 337                 goto badframe;
 338
 339         frame = (struct sigframe __user *)regs->ARM_sp;
 340
 341         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 342                 goto badframe;
 343
 344         if (restore_sigframe(regs, frame))
 345                 goto badframe;
 346
 347         return regs->ARM_r0;
 348
 349 badframe:
 350         force_sig(SIGSEGV, current);
 351         return 0;
 352 }
 353
 354 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 355 {
 356         struct rt_sigframe __user *frame;
 357
 358         /* Always make any pending restarted system calls return -EINTR */
 359         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 360
 361         /*
 362          * Since we stacked the signal on a 64-bit boundary,
 363          * then 'sp' should be word aligned here.  If it's
 364          * not, then the user is trying to mess with us.
 365          */
 366         if (regs->ARM_sp & 7)
 367                 goto badframe;
 368
 369         frame = (struct rt_sigframe __user *)regs->ARM_sp;
 370
 371         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 372                 goto badframe;
 373
 374         if (restore_sigframe(regs, &frame->sig))
 375                 goto badframe;
 376
 377         if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
 378                 goto badframe;
 379
 380         return regs->ARM_r0;
 381
 382 badframe:
 383         force_sig(SIGSEGV, current);
 384         return 0;
 385 }
 386
 387 static int
 388 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 389 {
 390         struct aux_sigframe __user *aux;
 391         int err = 0;
 392
 393         __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 394         __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 395         __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 396         __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 397         __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 398         __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 399         __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 400         __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 401         __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 402         __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 403         __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 404         __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 405         __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 406         __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 407         __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 408         __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 409         __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 410
 411         __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
 412         __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
 413         __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
 414         __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
 415
 416         err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
 417
 418         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 419 #ifdef CONFIG_CRUNCH
 420         if (err == 0)
 421                 err |= preserve_crunch_context(&aux->crunch);
 422 #endif
 423 #ifdef CONFIG_IWMMXT
 424         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 425                 err |= preserve_iwmmxt_context(&aux->iwmmxt);
 426 #endif
 427 #ifdef CONFIG_VFP
 428         if (err == 0)
 429                 err |= preserve_vfp_context(&aux->vfp);
 430 #endif
 431         __put_user_error(0, &aux->end_magic, err);
 432
 433         return err;
 434 }
 435
 436 static inline void __user *
 437 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 438 {
 439         unsigned long sp = regs->ARM_sp;
 440         void __user *frame;
 441
 442         /*
 443          * This is the X/Open sanctioned signal stack switching.
 444          */
 445         if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
 446                 sp = current->sas_ss_sp + current->sas_ss_size;
 447
 448         /*
 449          * ATPCS B01 mandates 8-byte alignment
 450          */
 451         frame = (void __user *)((sp - framesize) & ~7);
 452
 453         /*
 454          * Check that we can actually write to the signal frame.
 455          */
 456         if (!access_ok(VERIFY_WRITE, frame, framesize))
 457                 frame = NULL;
 458
 459         return frame;
 460 }
 461
 462 static int
 463 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 464              unsigned long __user *rc, void __user *frame, int usig)
 465 {
 466         unsigned long handler = (unsigned long)ka->sa.sa_handler;
 467         unsigned long retcode;
 468         int thumb = 0;
 469         unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
 470
 471         cpsr |= PSR_ENDSTATE;
 472
 473         /*
 474          * Maybe we need to deliver a 32-bit signal to a 26-bit task.
 475          */
 476         if (ka->sa.sa_flags & SA_THIRTYTWO)
 477                 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
 478
 479 #ifdef CONFIG_ARM_THUMB
 480         if (elf_hwcap & HWCAP_THUMB) {
 481                 /*
 482                  * The LSB of the handler determines if we're going to
 483                  * be using THUMB or ARM mode for this signal handler.
 484                  */
 485                 thumb = handler & 1;
 486
 487                 if (thumb) {
 488                         cpsr |= PSR_T_BIT;
 489 #if __LINUX_ARM_ARCH__ >= 7
 490                         /* clear the If-Then Thumb-2 execution state */
 491                         cpsr &= ~PSR_IT_MASK;
 492 #endif
 493                 } else
 494                         cpsr &= ~PSR_T_BIT;
 495         }
 496 #endif
 497
 498         if (ka->sa.sa_flags & SA_RESTORER) {
 499                 retcode = (unsigned long)ka->sa.sa_restorer;
 500         } else {
 501                 unsigned int idx = thumb << 1;
 502
 503                 if (ka->sa.sa_flags & SA_SIGINFO)
 504                         idx += 3;
 505
 506                 if (__put_user(sigreturn_codes[idx],   rc) ||
 507                     __put_user(sigreturn_codes[idx+1], rc+1))
 508                         return 1;
 509
 510                 if (cpsr & MODE32_BIT) {
 511                         /*
 512                          * 32-bit code can use the new high-page
 513                          * signal return code support.
 514                          */
 515                         retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
 516                 } else {
 517                         /*
 518                          * Ensure that the instruction cache sees
 519                          * the return code written onto the stack.
 520                          */
 521                         flush_icache_range((unsigned long)rc,
 522                                            (unsigned long)(rc + 2));
 523
 524                         retcode = ((unsigned long)rc) + thumb;
 525                 }
 526         }
 527
 528         regs->ARM_r0 = usig;
 529         regs->ARM_sp = (unsigned long)frame;
 530         regs->ARM_lr = retcode;
 531         regs->ARM_pc = handler;
 532         regs->ARM_cpsr = cpsr;
 533
 534         return 0;
 535 }
 536
 537 static int
 538 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
 539 {
 540         struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 541         int err = 0;
 542
 543         if (!frame)
 544                 return 1;
 545
 546         /*
 547          * Set uc.uc_flags to a value which sc.trap_no would never have.
 548          */
 549         __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
 550
 551         err |= setup_sigframe(frame, regs, set);
 552         if (err == 0)
 553                 err = setup_return(regs, ka, frame->retcode, frame, usig);
 554
 555         return err;
 556 }
 557
 558 static int
 559 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 560                sigset_t *set, struct pt_regs *regs)
 561 {
 562         struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 563         stack_t stack;
 564         int err = 0;
 565
 566         if (!frame)
 567                 return 1;
 568
 569         err |= copy_siginfo_to_user(&frame->info, info);
 570
 571         __put_user_error(0, &frame->sig.uc.uc_flags, err);
 572         __put_user_error(NULL, &frame->sig.uc.uc_link, err);
 573
 574         memset(&stack, 0, sizeof(stack));
 575         stack.ss_sp = (void __user *)current->sas_ss_sp;
 576         stack.ss_flags = sas_ss_flags(regs->ARM_sp);
 577         stack.ss_size = current->sas_ss_size;
 578         err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
 579
 580         err |= setup_sigframe(&frame->sig, regs, set);
 581         if (err == 0)
 582                 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
 583
 584         if (err == 0) {
 585                 /*
 586                  * For realtime signals we must also set the second and third
 587                  * arguments for the signal handler.
 588                  *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
 589                  */
 590                 regs->ARM_r1 = (unsigned long)&frame->info;
 591                 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
 592         }
 593
 594         return err;
 595 }
 596
 597 /*
 598  * OK, we're invoking a handler
 599  */
 600 static int
 601 handle_signal(unsigned long sig, struct k_sigaction *ka,
 602               siginfo_t *info, sigset_t *oldset,
 603               struct pt_regs * regs)
 604 {
 605         struct thread_info *thread = current_thread_info();
 606         struct task_struct *tsk = current;
 607         int usig = sig;
 608         int ret;
 609
 610         /*
 611          * translate the signal
 612          */
 613         if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
 614                 usig = thread->exec_domain->signal_invmap[usig];
 615
 616         /*
 617          * Set up the stack frame
 618          */
 619         if (ka->sa.sa_flags & SA_SIGINFO)
 620                 ret = setup_rt_frame(usig, ka, info, oldset, regs);
 621         else
 622                 ret = setup_frame(usig, ka, oldset, regs);
 623
 624         /*
 625          * Check that the resulting registers are actually sane.
 626          */
 627         ret |= !valid_user_regs(regs);
 628
 629         if (ret != 0) {
 630                 force_sigsegv(sig, tsk);
 631                 return ret;
 632         }
 633
 634         /*
 635          * Block the signal if we were successful.
 636          */
 637         block_sigmask(ka, sig);
 638
 639         return 0;
 640 }
 641
 642 /*
 643  * Note that 'init' is a special process: it doesn't get signals it doesn't
 644  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 645  * mistake.
 646  *
 647  * Note that we go through the signals twice: once to check the signals that
 648  * the kernel can handle, and then we build all the user-level signal handling
 649  * stack-frames in one go after that.
 650  */
 651 static void do_signal(struct pt_regs *regs, int syscall)
 652 {
 653         unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
 654         struct k_sigaction ka;
 655         siginfo_t info;
 656         int signr;
 657
 658         /*
 659          * We want the common case to go fast, which
 660          * is why we may in certain cases get here from
 661          * kernel mode. Just return without doing anything
 662          * if so.
 663          */
 664         if (!user_mode(regs))
 665                 return;
 666
 667         /*
 668          * If we were from a system call, check for system call restarting...
 669          */
 670         if (syscall) {
 671                 continue_addr = regs->ARM_pc;
 672                 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
 673                 retval = regs->ARM_r0;
 674
 675                 /*
 676                  * Prepare for system call restart.  We do this here so that a
 677                  * debugger will see the already changed PSW.
 678                  */
 679                 switch (retval) {
 680                 case -ERESTARTNOHAND:
 681                 case -ERESTARTSYS:
 682                 case -ERESTARTNOINTR:
 683                         regs->ARM_r0 = regs->ARM_ORIG_r0;
 684                         regs->ARM_pc = restart_addr;
 685                         break;
 686                 case -ERESTART_RESTARTBLOCK:
 687                         regs->ARM_r0 = -EINTR;
 688                         break;
 689                 }
 690         }
 691
 692         if (try_to_freeze())
 693                 goto no_signal;
 694
 695         /*
 696          * Get the signal to deliver.  When running under ptrace, at this
 697          * point the debugger may change all our registers ...
 698          */
 699         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 700         if (signr > 0) {
 701                 sigset_t *oldset;
 702
 703                 /*
 704                  * Depending on the signal settings we may need to revert the
 705                  * decision to restart the system call.  But skip this if a
 706                  * debugger has chosen to restart at a different PC.
 707                  */
 708                 if (regs->ARM_pc == restart_addr) {
 709                         if (retval == -ERESTARTNOHAND
 710                             || (retval == -ERESTARTSYS
 711                                 && !(ka.sa.sa_flags & SA_RESTART))) {
 712                                 regs->ARM_r0 = -EINTR;
 713                                 regs->ARM_pc = continue_addr;
 714                         }
 715                 }
 716
 717                 if (test_thread_flag(TIF_RESTORE_SIGMASK))
 718                         oldset = &current->saved_sigmask;
 719                 else
 720                         oldset = &current->blocked;
 721                 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
 722                         /*
 723                          * A signal was successfully delivered; the saved
 724                          * sigmask will have been stored in the signal frame,
 725                          * and will be restored by sigreturn, so we can simply
 726                          * clear the TIF_RESTORE_SIGMASK flag.
 727                          */
 728                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 729                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 730                 }
 731                 return;
 732         }
 733
 734  no_signal:
 735         if (syscall) {
 736                 /*
 737                  * Handle restarting a different system call.  As above,
 738                  * if a debugger has chosen to restart at a different PC,
 739                  * ignore the restart.
 740                  */
 741                 if (retval == -ERESTART_RESTARTBLOCK
 742                     && regs->ARM_pc == continue_addr) {
 743                         if (thumb_mode(regs)) {
 744                                 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
 745                                 regs->ARM_pc -= 2;
 746                         } else {
 747 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
 748                                 regs->ARM_r7 = __NR_restart_syscall;
 749                                 regs->ARM_pc -= 4;
 750 #else
 751                                 u32 __user *usp;
 752
 753                                 regs->ARM_sp -= 4;
 754                                 usp = (u32 __user *)regs->ARM_sp;
 755
 756                                 if (put_user(regs->ARM_pc, usp) == 0) {
 757                                         regs->ARM_pc = KERN_RESTART_CODE;
 758                                 } else {
 759                                         regs->ARM_sp += 4;
 760                                         force_sigsegv(0, current);
 761                                 }
 762 #endif
 763                         }
 764                 }
 765
 766                 /* If there's no signal to deliver, we just put the saved sigmask
 767                  * back.
 768                  */
 769                 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 770                         clear_thread_flag(TIF_RESTORE_SIGMASK);
 771                         sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 772                 }
 773         }
 774 }
 775
 776 asmlinkage void
 777 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 778 {
 779         if (thread_flags & _TIF_SIGPENDING)
 780                 do_signal(regs, syscall);
 781
 782         if (thread_flags & _TIF_NOTIFY_RESUME) {
 783                 clear_thread_flag(TIF_NOTIFY_RESUME);
 784                 tracehook_notify_resume(regs);
 785                 if (current->replacement_session_keyring)
 786                         key_replace_session_keyring();
 787         }
 788 }