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         mask &= _BLOCKABLE;
  70         spin_lock_irq(&current->sighand->siglock);
  71         current->saved_sigmask = current->blocked;
  72         siginitset(&current->blocked, mask);
  73         recalc_sigpending();
  74         spin_unlock_irq(&current->sighand->siglock);
  75
  76         current->state = TASK_INTERRUPTIBLE;
  77         schedule();
  78         set_restore_sigmask();
  79         return -ERESTARTNOHAND;
  80 }
  81
  82 asmlinkage int
  83 sys_sigaction(int sig, const struct old_sigaction __user *act,
  84               struct old_sigaction __user *oact)
  85 {
  86         struct k_sigaction new_ka, old_ka;
  87         int ret;
  88
  89         if (act) {
  90                 old_sigset_t mask;
  91                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  92                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  93                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  94                         return -EFAULT;
  95                 __get_user(new_ka.sa.sa_flags, &act->sa_flags);
  96                 __get_user(mask, &act->sa_mask);
  97                 siginitset(&new_ka.sa.sa_mask, mask);
  98         }
  99
 100         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
 101
 102         if (!ret && oact) {
 103                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
 104                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
 105                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
 106                         return -EFAULT;
 107                 __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 108                 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
 109         }
 110
 111         return ret;
 112 }
 113
 114 #ifdef CONFIG_CRUNCH
 115 static int preserve_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         kframe->magic = CRUNCH_MAGIC;
 123         kframe->size = CRUNCH_STORAGE_SIZE;
 124         crunch_task_copy(current_thread_info(), &kframe->storage);
 125         return __copy_to_user(frame, kframe, sizeof(*frame));
 126 }
 127
 128 static int restore_crunch_context(struct crunch_sigframe __user *frame)
 129 {
 130         char kbuf[sizeof(*frame) + 8];
 131         struct crunch_sigframe *kframe;
 132
 133         /* the crunch context must be 64 bit aligned */
 134         kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 135         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 136                 return -1;
 137         if (kframe->magic != CRUNCH_MAGIC ||
 138             kframe->size != CRUNCH_STORAGE_SIZE)
 139                 return -1;
 140         crunch_task_restore(current_thread_info(), &kframe->storage);
 141         return 0;
 142 }
 143 #endif
 144
 145 #ifdef CONFIG_IWMMXT
 146
 147 static int preserve_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         kframe->magic = IWMMXT_MAGIC;
 155         kframe->size = IWMMXT_STORAGE_SIZE;
 156         iwmmxt_task_copy(current_thread_info(), &kframe->storage);
 157         return __copy_to_user(frame, kframe, sizeof(*frame));
 158 }
 159
 160 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
 161 {
 162         char kbuf[sizeof(*frame) + 8];
 163         struct iwmmxt_sigframe *kframe;
 164
 165         /* the iWMMXt context must be 64 bit aligned */
 166         kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
 167         if (__copy_from_user(kframe, frame, sizeof(*frame)))
 168                 return -1;
 169         if (kframe->magic != IWMMXT_MAGIC ||
 170             kframe->size != IWMMXT_STORAGE_SIZE)
 171                 return -1;
 172         iwmmxt_task_restore(current_thread_info(), &kframe->storage);
 173         return 0;
 174 }
 175
 176 #endif
 177
 178 #ifdef CONFIG_VFP
 179
 180 static int preserve_vfp_context(struct vfp_sigframe __user *frame)
 181 {
 182         struct thread_info *thread = current_thread_info();
 183         struct vfp_hard_struct *h = &thread->vfpstate.hard;
 184         const unsigned long magic = VFP_MAGIC;
 185         const unsigned long size = VFP_STORAGE_SIZE;
 186         int err = 0;
 187
 188         vfp_sync_hwstate(thread);
 189         __put_user_error(magic, &frame->magic, err);
 190         __put_user_error(size, &frame->size, err);
 191
 192         /*
 193          * Copy the floating point registers. There can be unused
 194          * registers see asm/hwcap.h for details.
 195          */
 196         err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs,
 197                               sizeof(h->fpregs));
 198         /*
 199          * Copy the status and control register.
 200          */
 201         __put_user_error(h->fpscr, &frame->ufp.fpscr, err);
 202
 203         /*
 204          * Copy the exception registers.
 205          */
 206         __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err);
 207         __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
 208         __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
 209
 210         return err ? -EFAULT : 0;
 211 }
 212
 213 static int restore_vfp_context(struct vfp_sigframe __user *frame)
 214 {
 215         struct thread_info *thread = current_thread_info();
 216         struct vfp_hard_struct *h = &thread->vfpstate.hard;
 217         unsigned long magic;
 218         unsigned long size;
 219         unsigned long fpexc;
 220         int err = 0;
 221
 222         __get_user_error(magic, &frame->magic, err);
 223         __get_user_error(size, &frame->size, err);
 224
 225         if (err)
 226                 return -EFAULT;
 227         if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
 228                 return -EINVAL;
 229
 230         vfp_flush_hwstate(thread);
 231
 232         /*
 233          * Copy the floating point registers. There can be unused
 234          * registers see asm/hwcap.h for details.
 235          */
 236         err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs,
 237                                 sizeof(h->fpregs));
 238         /*
 239          * Copy the status and control register.
 240          */
 241         __get_user_error(h->fpscr, &frame->ufp.fpscr, err);
 242
 243         /*
 244          * Sanitise and restore the exception registers.
 245          */
 246         __get_user_error(fpexc, &frame->ufp_exc.fpexc, err);
 247         /* Ensure the VFP is enabled. */
 248         fpexc |= FPEXC_EN;
 249         /* Ensure FPINST2 is invalid and the exception flag is cleared. */
 250         fpexc &= ~(FPEXC_EX | FPEXC_FP2V);
 251         h->fpexc = fpexc;
 252
 253         __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err);
 254         __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err);
 255
 256         return err ? -EFAULT : 0;
 257 }
 258
 259 #endif
 260
 261 /*
 262  * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
 263  */
 264 struct sigframe {
 265         struct ucontext uc;
 266         unsigned long retcode[2];
 267 };
 268
 269 struct rt_sigframe {
 270         struct siginfo info;
 271         struct sigframe sig;
 272 };
 273
 274 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
 275 {
 276         struct aux_sigframe __user *aux;
 277         sigset_t set;
 278         int err;
 279
 280         err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
 281         if (err == 0) {
 282                 sigdelsetmask(&set, ~_BLOCKABLE);
 283                 spin_lock_irq(&current->sighand->siglock);
 284                 current->blocked = set;
 285                 recalc_sigpending();
 286                 spin_unlock_irq(&current->sighand->siglock);
 287         }
 288
 289         __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 290         __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 291         __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 292         __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 293         __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 294         __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 295         __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 296         __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 297         __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 298         __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 299         __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 300         __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 301         __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 302         __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 303         __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 304         __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 305         __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 306
 307         err |= !valid_user_regs(regs);
 308
 309         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 310 #ifdef CONFIG_CRUNCH
 311         if (err == 0)
 312                 err |= restore_crunch_context(&aux->crunch);
 313 #endif
 314 #ifdef CONFIG_IWMMXT
 315         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 316                 err |= restore_iwmmxt_context(&aux->iwmmxt);
 317 #endif
 318 #ifdef CONFIG_VFP
 319         if (err == 0)
 320                 err |= restore_vfp_context(&aux->vfp);
 321 #endif
 322
 323         return err;
 324 }
 325
 326 asmlinkage int sys_sigreturn(struct pt_regs *regs)
 327 {
 328         struct sigframe __user *frame;
 329
 330         /* Always make any pending restarted system calls return -EINTR */
 331         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 332
 333         /*
 334          * Since we stacked the signal on a 64-bit boundary,
 335          * then 'sp' should be word aligned here.  If it's
 336          * not, then the user is trying to mess with us.
 337          */
 338         if (regs->ARM_sp & 7)
 339                 goto badframe;
 340
 341         frame = (struct sigframe __user *)regs->ARM_sp;
 342
 343         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 344                 goto badframe;
 345
 346         if (restore_sigframe(regs, frame))
 347                 goto badframe;
 348
 349         return regs->ARM_r0;
 350
 351 badframe:
 352         force_sig(SIGSEGV, current);
 353         return 0;
 354 }
 355
 356 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 357 {
 358         struct rt_sigframe __user *frame;
 359
 360         /* Always make any pending restarted system calls return -EINTR */
 361         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 362
 363         /*
 364          * Since we stacked the signal on a 64-bit boundary,
 365          * then 'sp' should be word aligned here.  If it's
 366          * not, then the user is trying to mess with us.
 367          */
 368         if (regs->ARM_sp & 7)
 369                 goto badframe;
 370
 371         frame = (struct rt_sigframe __user *)regs->ARM_sp;
 372
 373         if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
 374                 goto badframe;
 375
 376         if (restore_sigframe(regs, &frame->sig))
 377                 goto badframe;
 378
 379         if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
 380                 goto badframe;
 381
 382         return regs->ARM_r0;
 383
 384 badframe:
 385         force_sig(SIGSEGV, current);
 386         return 0;
 387 }
 388
 389 static int
 390 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 391 {
 392         struct aux_sigframe __user *aux;
 393         int err = 0;
 394
 395         __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
 396         __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
 397         __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
 398         __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
 399         __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
 400         __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
 401         __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
 402         __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
 403         __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
 404         __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
 405         __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
 406         __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
 407         __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
 408         __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
 409         __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
 410         __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
 411         __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
 412
 413         __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
 414         __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
 415         __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
 416         __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
 417
 418         err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
 419
 420         aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
 421 #ifdef CONFIG_CRUNCH
 422         if (err == 0)
 423                 err |= preserve_crunch_context(&aux->crunch);
 424 #endif
 425 #ifdef CONFIG_IWMMXT
 426         if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
 427                 err |= preserve_iwmmxt_context(&aux->iwmmxt);
 428 #endif
 429 #ifdef CONFIG_VFP
 430         if (err == 0)
 431                 err |= preserve_vfp_context(&aux->vfp);
 432 #endif
 433         __put_user_error(0, &aux->end_magic, err);
 434
 435         return err;
 436 }
 437
 438 static inline void __user *
 439 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 440 {
 441         unsigned long sp = regs->ARM_sp;
 442         void __user *frame;
 443
 444         /*
 445          * This is the X/Open sanctioned signal stack switching.
 446          */
 447         if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
 448                 sp = current->sas_ss_sp + current->sas_ss_size;
 449
 450         /*
 451          * ATPCS B01 mandates 8-byte alignment
 452          */
 453         frame = (void __user *)((sp - framesize) & ~7);
 454
 455         /*
 456          * Check that we can actually write to the signal frame.
 457          */
 458         if (!access_ok(VERIFY_WRITE, frame, framesize))
 459                 frame = NULL;
 460
 461         return frame;
 462 }
 463
 464 static int
 465 setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 466              unsigned long __user *rc, void __user *frame, int usig)
 467 {
 468         unsigned long handler = (unsigned long)ka->sa.sa_handler;
 469         unsigned long retcode;
 470         int thumb = 0;
 471         unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
 472
 473         cpsr |= PSR_ENDSTATE;
 474
 475         /*
 476          * Maybe we need to deliver a 32-bit signal to a 26-bit task.
 477          */
 478         if (ka->sa.sa_flags & SA_THIRTYTWO)
 479                 cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
 480
 481 #ifdef CONFIG_ARM_THUMB
 482         if (elf_hwcap & HWCAP_THUMB) {
 483                 /*
 484                  * The LSB of the handler determines if we're going to
 485                  * be using THUMB or ARM mode for this signal handler.
 486                  */
 487                 thumb = handler & 1;
 488
 489                 if (thumb) {
 490                         cpsr |= PSR_T_BIT;
 491 #if __LINUX_ARM_ARCH__ >= 7
 492                         /* clear the If-Then Thumb-2 execution state */
 493                         cpsr &= ~PSR_IT_MASK;
 494 #endif
 495                 } else
 496                         cpsr &= ~PSR_T_BIT;
 497         }
 498 #endif
 499
 500         if (ka->sa.sa_flags & SA_RESTORER) {
 501                 retcode = (unsigned long)ka->sa.sa_restorer;
 502         } else {
 503                 unsigned int idx = thumb << 1;
 504
 505                 if (ka->sa.sa_flags & SA_SIGINFO)
 506                         idx += 3;
 507
 508                 if (__put_user(sigreturn_codes[idx],   rc) ||
 509                     __put_user(sigreturn_codes[idx+1], rc+1))
 510                         return 1;
 511
 512                 if (cpsr & MODE32_BIT) {
 513                         /*
 514                          * 32-bit code can use the new high-page
 515                          * signal return code support.
 516                          */
 517                         retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
 518                 } else {
 519                         /*
 520                          * Ensure that the instruction cache sees
 521                          * the return code written onto the stack.
 522                          */
 523                         flush_icache_range((unsigned long)rc,
 524                                            (unsigned long)(rc + 2));
 525
 526                         retcode = ((unsigned long)rc) + thumb;
 527                 }
 528         }
 529
 530         regs->ARM_r0 = usig;
 531         regs->ARM_sp = (unsigned long)frame;
 532         regs->ARM_lr = retcode;
 533         regs->ARM_pc = handler;
 534         regs->ARM_cpsr = cpsr;
 535
 536         return 0;
 537 }
 538
 539 static int
 540 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
 541 {
 542         struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 543         int err = 0;
 544
 545         if (!frame)
 546                 return 1;
 547
 548         /*
 549          * Set uc.uc_flags to a value which sc.trap_no would never have.
 550          */
 551         __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
 552
 553         err |= setup_sigframe(frame, regs, set);
 554         if (err == 0)
 555                 err = setup_return(regs, ka, frame->retcode, frame, usig);
 556
 557         return err;
 558 }
 559
 560 static int
 561 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 562                sigset_t *set, struct pt_regs *regs)
 563 {
 564         struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
 565         stack_t stack;
 566         int err = 0;
 567
 568         if (!frame)
 569                 return 1;
 570
 571         err |= copy_siginfo_to_user(&frame->info, info);
 572
 573         __put_user_error(0, &frame->sig.uc.uc_flags, err);
 574         __put_user_error(NULL, &frame->sig.uc.uc_link, err);
 575
 576         memset(&stack, 0, sizeof(stack));
 577         stack.ss_sp = (void __user *)current->sas_ss_sp;
 578         stack.ss_flags = sas_ss_flags(regs->ARM_sp);
 579         stack.ss_size = current->sas_ss_size;
 580         err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
 581
 582         err |= setup_sigframe(&frame->sig, regs, set);
 583         if (err == 0)
 584                 err = setup_return(regs, ka, frame->sig.retcode, frame, usig);
 585
 586         if (err == 0) {
 587                 /*
 588                  * For realtime signals we must also set the second and third
 589                  * arguments for the signal handler.
 590                  *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
 591                  */
 592                 regs->ARM_r1 = (unsigned long)&frame->info;
 593                 regs->ARM_r2 = (unsigned long)&frame->sig.uc;
 594         }
 595
 596         return err;
 597 }
 598
 599 /*
 600  * OK, we're invoking a handler
 601  */
 602 static int
 603 handle_signal(unsigned long sig, struct k_sigaction *ka,
 604               siginfo_t *info, sigset_t *oldset,
 605               struct pt_regs * regs)
 606 {
 607         struct thread_info *thread = current_thread_info();
 608         struct task_struct *tsk = current;
 609         int usig = sig;
 610         int ret;
 611
 612         /*
 613          * translate the signal
 614          */
 615         if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
 616                 usig = thread->exec_domain->signal_invmap[usig];
 617
 618         /*
 619          * Set up the stack frame
 620          */
 621         if (ka->sa.sa_flags & SA_SIGINFO)
 622                 ret = setup_rt_frame(usig, ka, info, oldset, regs);
 623         else
 624                 ret = setup_frame(usig, ka, oldset, regs);
 625
 626         /*
 627          * Check that the resulting registers are actually sane.
 628          */
 629         ret |= !valid_user_regs(regs);
 630
 631         if (ret != 0) {
 632                 force_sigsegv(sig, tsk);
 633                 return ret;
 634         }
 635
 636         /*
 637          * Block the signal if we were successful.
 638          */
 639         spin_lock_irq(&tsk->sighand->siglock);
 640         sigorsets(&tsk->blocked, &tsk->blocked,
 641                   &ka->sa.sa_mask);
 642         if (!(ka->sa.sa_flags & SA_NODEFER))
 643                 sigaddset(&tsk->blocked, sig);
 644         recalc_sigpending();
 645         spin_unlock_irq(&tsk->sighand->siglock);
 646
 647         return 0;
 648 }
 649
 650 /*
 651  * Note that 'init' is a special process: it doesn't get signals it doesn't
 652  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 653  * mistake.
 654  *
 655  * Note that we go through the signals twice: once to check the signals that
 656  * the kernel can handle, and then we build all the user-level signal handling
 657  * stack-frames in one go after that.
 658  */
 659 static void do_signal(struct pt_regs *regs, int syscall)
 660 {
 661         unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
 662         struct k_sigaction ka;
 663         siginfo_t info;
 664         int signr;
 665
 666         /*
 667          * We want the common case to go fast, which
 668          * is why we may in certain cases get here from
 669          * kernel mode. Just return without doing anything
 670          * if so.
 671          */
 672         if (!user_mode(regs))
 673                 return;
 674
 675         /*
 676          * If we were from a system call, check for system call restarting...
 677          */
 678         if (syscall) {
 679                 continue_addr = regs->ARM_pc;
 680                 restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
 681                 retval = regs->ARM_r0;
 682
 683                 /*
 684                  * Prepare for system call restart.  We do this here so that a
 685                  * debugger will see the already changed PSW.
 686                  */
 687                 switch (retval) {
 688                 case -ERESTARTNOHAND:
 689                 case -ERESTARTSYS:
 690                 case -ERESTARTNOINTR:
 691                         regs->ARM_r0 = regs->ARM_ORIG_r0;
 692                         regs->ARM_pc = restart_addr;
 693                         break;
 694                 case -ERESTART_RESTARTBLOCK:
 695                         regs->ARM_r0 = -EINTR;
 696                         break;
 697                 }
 698         }
 699
 700         if (try_to_freeze())
 701                 goto no_signal;
 702
 703         /*
 704          * Get the signal to deliver.  When running under ptrace, at this
 705          * point the debugger may change all our registers ...
 706          */
 707         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 708         if (signr > 0) {
 709                 sigset_t *oldset;
 710
 711                 /*
 712                  * Depending on the signal settings we may need to revert the
 713                  * decision to restart the system call.  But skip this if a
 714                  * debugger has chosen to restart at a different PC.
 715                  */
 716                 if (regs->ARM_pc == restart_addr) {
 717                         if (retval == -ERESTARTNOHAND
 718                             || (retval == -ERESTARTSYS
 719                                 && !(ka.sa.sa_flags & SA_RESTART))) {
 720                                 regs->ARM_r0 = -EINTR;
 721                                 regs->ARM_pc = continue_addr;
 722                         }
 723                 }
 724
 725                 if (test_thread_flag(TIF_RESTORE_SIGMASK))
 726                         oldset = &current->saved_sigmask;
 727                 else
 728                         oldset = &current->blocked;
 729                 if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
 730                         /*
 731                          * A signal was successfully delivered; the saved
 732                          * sigmask will have been stored in the signal frame,
 733                          * and will be restored by sigreturn, so we can simply
 734                          * clear the TIF_RESTORE_SIGMASK flag.
 735                          */
 736                         if (test_thread_flag(TIF_RESTORE_SIGMASK))
 737                                 clear_thread_flag(TIF_RESTORE_SIGMASK);
 738                 }
 739                 return;
 740         }
 741
 742  no_signal:
 743         if (syscall) {
 744                 /*
 745                  * Handle restarting a different system call.  As above,
 746                  * if a debugger has chosen to restart at a different PC,
 747                  * ignore the restart.
 748                  */
 749                 if (retval == -ERESTART_RESTARTBLOCK
 750                     && regs->ARM_pc == continue_addr) {
 751                         if (thumb_mode(regs)) {
 752                                 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
 753                                 regs->ARM_pc -= 2;
 754                         } else {
 755 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
 756                                 regs->ARM_r7 = __NR_restart_syscall;
 757                                 regs->ARM_pc -= 4;
 758 #else
 759                                 u32 __user *usp;
 760
 761                                 regs->ARM_sp -= 4;
 762                                 usp = (u32 __user *)regs->ARM_sp;
 763
 764                                 if (put_user(regs->ARM_pc, usp) == 0) {
 765                                         regs->ARM_pc = KERN_RESTART_CODE;
 766                                 } else {
 767                                         regs->ARM_sp += 4;
 768                                         force_sigsegv(0, current);
 769                                 }
 770 #endif
 771                         }
 772                 }
 773
 774                 /* If there's no signal to deliver, we just put the saved sigmask
 775                  * back.
 776                  */
 777                 if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
 778                         clear_thread_flag(TIF_RESTORE_SIGMASK);
 779                         sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 780                 }
 781         }
 782 }
 783
 784 asmlinkage void
 785 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 786 {
 787         if (thread_flags & _TIF_SIGPENDING)
 788                 do_signal(regs, syscall);
 789
 790         if (thread_flags & _TIF_NOTIFY_RESUME) {
 791                 clear_thread_flag(TIF_NOTIFY_RESUME);
 792                 tracehook_notify_resume(regs);
 793                 if (current->replacement_session_keyring)
 794                         key_replace_session_keyring();
 795         }
 796 }