arch/sh/kernel/signal_32.c

   1 /*
   2  *  linux/arch/sh/kernel/signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *
   6  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   7  *
   8  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
   9  *
  10  */
  11 #include <linux/sched.h>
  12 #include <linux/mm.h>
  13 #include <linux/smp.h>
  14 #include <linux/kernel.h>
  15 #include <linux/signal.h>
  16 #include <linux/errno.h>
  17 #include <linux/wait.h>
  18 #include <linux/ptrace.h>
  19 #include <linux/unistd.h>
  20 #include <linux/stddef.h>
  21 #include <linux/tty.h>
  22 #include <linux/elf.h>
  23 #include <linux/personality.h>
  24 #include <linux/binfmts.h>
  25 #include <linux/io.h>
  26 #include <linux/tracehook.h>
  27 #include <asm/ucontext.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/pgtable.h>
  30 #include <asm/cacheflush.h>
  31 #include <asm/syscalls.h>
  32 #include <asm/fpu.h>
  33
  34 struct fdpic_func_descriptor {
  35         unsigned long   text;
  36         unsigned long   GOT;
  37 };
  38
  39 /*
  40  * The following define adds a 64 byte gap between the signal
  41  * stack frame and previous contents of the stack.  This allows
  42  * frame unwinding in a function epilogue but only if a frame
  43  * pointer is used in the function.  This is necessary because
  44  * current gcc compilers (<4.3) do not generate unwind info on
  45  * SH for function epilogues.
  46  */
  47 #define UNWINDGUARD 64
  48
  49 /*
  50  * Atomically swap in the new signal mask, and wait for a signal.
  51  */
  52 asmlinkage int
  53 sys_sigsuspend(old_sigset_t mask)
  54 {
  55         sigset_t blocked;
  56         siginitset(&blocked, mask);
  57         return sigsuspend(&blocked);
  58 }
  59
  60 asmlinkage int
  61 sys_sigaction(int sig, const struct old_sigaction __user *act,
  62               struct old_sigaction __user *oact)
  63 {
  64         struct k_sigaction new_ka, old_ka;
  65         int ret;
  66
  67         if (act) {
  68                 old_sigset_t mask;
  69                 if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  70                     __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  71                     __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
  72                     __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
  73                     __get_user(mask, &act->sa_mask))
  74                         return -EFAULT;
  75                 siginitset(&new_ka.sa.sa_mask, mask);
  76         }
  77
  78         ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  79
  80         if (!ret && oact) {
  81                 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  82                     __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  83                     __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
  84                     __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
  85                     __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
  86                         return -EFAULT;
  87         }
  88
  89         return ret;
  90 }
  91
  92 asmlinkage int
  93 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  94                 unsigned long r6, unsigned long r7,
  95                 struct pt_regs __regs)
  96 {
  97         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
  98
  99         return do_sigaltstack(uss, uoss, regs->regs[15]);
 100 }
 101
 102
 103 /*
 104  * Do a signal return; undo the signal stack.
 105  */
 106
 107 #define MOVW(n)  (0x9300|((n)-2))       /* Move mem word at PC+n to R3 */
 108 #if defined(CONFIG_CPU_SH2)
 109 #define TRAP_NOARG 0xc320               /* Syscall w/no args (NR in R3) */
 110 #else
 111 #define TRAP_NOARG 0xc310               /* Syscall w/no args (NR in R3) */
 112 #endif
 113 #define OR_R0_R0 0x200b                 /* or r0,r0 (insert to avoid hardware bug) */
 114
 115 struct sigframe
 116 {
 117         struct sigcontext sc;
 118         unsigned long extramask[_NSIG_WORDS-1];
 119         u16 retcode[8];
 120 };
 121
 122 struct rt_sigframe
 123 {
 124         struct siginfo info;
 125         struct ucontext uc;
 126         u16 retcode[8];
 127 };
 128
 129 #ifdef CONFIG_SH_FPU
 130 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
 131 {
 132         struct task_struct *tsk = current;
 133
 134         if (!(boot_cpu_data.flags & CPU_HAS_FPU))
 135                 return 0;
 136
 137         set_used_math();
 138         return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0],
 139                                 sizeof(long)*(16*2+2));
 140 }
 141
 142 static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
 143                                       struct pt_regs *regs)
 144 {
 145         struct task_struct *tsk = current;
 146
 147         if (!(boot_cpu_data.flags & CPU_HAS_FPU))
 148                 return 0;
 149
 150         if (!used_math())
 151                 return __put_user(0, &sc->sc_ownedfp);
 152
 153         if (__put_user(1, &sc->sc_ownedfp))
 154                 return -EFAULT;
 155
 156         /* This will cause a "finit" to be triggered by the next
 157            attempted FPU operation by the 'current' process.
 158            */
 159         clear_used_math();
 160
 161         unlazy_fpu(tsk, regs);
 162         return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu,
 163                               sizeof(long)*(16*2+2));
 164 }
 165 #endif /* CONFIG_SH_FPU */
 166
 167 static int
 168 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
 169 {
 170         unsigned int err = 0;
 171
 172 #define COPY(x)         err |= __get_user(regs->x, &sc->sc_##x)
 173                         COPY(regs[1]);
 174         COPY(regs[2]);  COPY(regs[3]);
 175         COPY(regs[4]);  COPY(regs[5]);
 176         COPY(regs[6]);  COPY(regs[7]);
 177         COPY(regs[8]);  COPY(regs[9]);
 178         COPY(regs[10]); COPY(regs[11]);
 179         COPY(regs[12]); COPY(regs[13]);
 180         COPY(regs[14]); COPY(regs[15]);
 181         COPY(gbr);      COPY(mach);
 182         COPY(macl);     COPY(pr);
 183         COPY(sr);       COPY(pc);
 184 #undef COPY
 185
 186 #ifdef CONFIG_SH_FPU
 187         if (boot_cpu_data.flags & CPU_HAS_FPU) {
 188                 int owned_fp;
 189                 struct task_struct *tsk = current;
 190
 191                 regs->sr |= SR_FD; /* Release FPU */
 192                 clear_fpu(tsk, regs);
 193                 clear_used_math();
 194                 err |= __get_user (owned_fp, &sc->sc_ownedfp);
 195                 if (owned_fp)
 196                         err |= restore_sigcontext_fpu(sc);
 197         }
 198 #endif
 199
 200         regs->tra = -1;         /* disable syscall checks */
 201         err |= __get_user(*r0_p, &sc->sc_regs[0]);
 202         return err;
 203 }
 204
 205 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
 206                              unsigned long r6, unsigned long r7,
 207                              struct pt_regs __regs)
 208 {
 209         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 210         struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];
 211         sigset_t set;
 212         int r0;
 213
 214         /* Always make any pending restarted system calls return -EINTR */
 215         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 216
 217         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 218                 goto badframe;
 219
 220         if (__get_user(set.sig[0], &frame->sc.oldmask)
 221             || (_NSIG_WORDS > 1
 222                 && __copy_from_user(&set.sig[1], &frame->extramask,
 223                                     sizeof(frame->extramask))))
 224                 goto badframe;
 225
 226         set_current_blocked(&set);
 227
 228         if (restore_sigcontext(regs, &frame->sc, &r0))
 229                 goto badframe;
 230         return r0;
 231
 232 badframe:
 233         force_sig(SIGSEGV, current);
 234         return 0;
 235 }
 236
 237 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
 238                                 unsigned long r6, unsigned long r7,
 239                                 struct pt_regs __regs)
 240 {
 241         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 242         struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];
 243         sigset_t set;
 244         int r0;
 245
 246         /* Always make any pending restarted system calls return -EINTR */
 247         current_thread_info()->restart_block.fn = do_no_restart_syscall;
 248
 249         if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 250                 goto badframe;
 251
 252         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 253                 goto badframe;
 254
 255         set_current_blocked(&set);
 256
 257         if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 258                 goto badframe;
 259
 260         if (do_sigaltstack(&frame->uc.uc_stack, NULL,
 261                            regs->regs[15]) == -EFAULT)
 262                 goto badframe;
 263
 264         return r0;
 265
 266 badframe:
 267         force_sig(SIGSEGV, current);
 268         return 0;
 269 }
 270
 271 /*
 272  * Set up a signal frame.
 273  */
 274
 275 static int
 276 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 277                  unsigned long mask)
 278 {
 279         int err = 0;
 280
 281 #define COPY(x)         err |= __put_user(regs->x, &sc->sc_##x)
 282         COPY(regs[0]);  COPY(regs[1]);
 283         COPY(regs[2]);  COPY(regs[3]);
 284         COPY(regs[4]);  COPY(regs[5]);
 285         COPY(regs[6]);  COPY(regs[7]);
 286         COPY(regs[8]);  COPY(regs[9]);
 287         COPY(regs[10]); COPY(regs[11]);
 288         COPY(regs[12]); COPY(regs[13]);
 289         COPY(regs[14]); COPY(regs[15]);
 290         COPY(gbr);      COPY(mach);
 291         COPY(macl);     COPY(pr);
 292         COPY(sr);       COPY(pc);
 293 #undef COPY
 294
 295 #ifdef CONFIG_SH_FPU
 296         err |= save_sigcontext_fpu(sc, regs);
 297 #endif
 298
 299         /* non-iBCS2 extensions.. */
 300         err |= __put_user(mask, &sc->oldmask);
 301
 302         return err;
 303 }
 304
 305 /*
 306  * Determine which stack to use..
 307  */
 308 static inline void __user *
 309 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 310 {
 311         if (ka->sa.sa_flags & SA_ONSTACK) {
 312                 if (sas_ss_flags(sp) == 0)
 313                         sp = current->sas_ss_sp + current->sas_ss_size;
 314         }
 315
 316         return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul);
 317 }
 318
 319 /* These symbols are defined with the addresses in the vsyscall page.
 320    See vsyscall-trapa.S.  */
 321 extern void __kernel_sigreturn(void);
 322 extern void __kernel_rt_sigreturn(void);
 323
 324 static int setup_frame(int sig, struct k_sigaction *ka,
 325                         sigset_t *set, struct pt_regs *regs)
 326 {
 327         struct sigframe __user *frame;
 328         int err = 0;
 329         int signal;
 330
 331         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 332
 333         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 334                 goto give_sigsegv;
 335
 336         signal = current_thread_info()->exec_domain
 337                 && current_thread_info()->exec_domain->signal_invmap
 338                 && sig < 32
 339                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 340                 : sig;
 341
 342         err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
 343
 344         if (_NSIG_WORDS > 1)
 345                 err |= __copy_to_user(frame->extramask, &set->sig[1],
 346                                       sizeof(frame->extramask));
 347
 348         /* Set up to return from userspace.  If provided, use a stub
 349            already in userspace.  */
 350         if (ka->sa.sa_flags & SA_RESTORER) {
 351                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 352 #ifdef CONFIG_VSYSCALL
 353         } else if (likely(current->mm->context.vdso)) {
 354                 regs->pr = VDSO_SYM(&__kernel_sigreturn);
 355 #endif
 356         } else {
 357                 /* Generate return code (system call to sigreturn) */
 358                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 359                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 360                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 361                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 362                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 363                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 364                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 365                 err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
 366                 regs->pr = (unsigned long) frame->retcode;
 367                 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
 368         }
 369
 370         if (err)
 371                 goto give_sigsegv;
 372
 373         /* Set up registers for signal handler */
 374         regs->regs[15] = (unsigned long) frame;
 375         regs->regs[4] = signal; /* Arg for signal handler */
 376         regs->regs[5] = 0;
 377         regs->regs[6] = (unsigned long) &frame->sc;
 378
 379         if (current->personality & FDPIC_FUNCPTRS) {
 380                 struct fdpic_func_descriptor __user *funcptr =
 381                         (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
 382
 383                 err |= __get_user(regs->pc, &funcptr->text);
 384                 err |= __get_user(regs->regs[12], &funcptr->GOT);
 385         } else
 386                 regs->pc = (unsigned long)ka->sa.sa_handler;
 387
 388         if (err)
 389                 goto give_sigsegv;
 390
 391         set_fs(USER_DS);
 392
 393         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 394                  current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
 395
 396         return 0;
 397
 398 give_sigsegv:
 399         force_sigsegv(sig, current);
 400         return -EFAULT;
 401 }
 402
 403 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 404                            sigset_t *set, struct pt_regs *regs)
 405 {
 406         struct rt_sigframe __user *frame;
 407         int err = 0;
 408         int signal;
 409
 410         frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
 411
 412         if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 413                 goto give_sigsegv;
 414
 415         signal = current_thread_info()->exec_domain
 416                 && current_thread_info()->exec_domain->signal_invmap
 417                 && sig < 32
 418                 ? current_thread_info()->exec_domain->signal_invmap[sig]
 419                 : sig;
 420
 421         err |= copy_siginfo_to_user(&frame->info, info);
 422
 423         /* Create the ucontext.  */
 424         err |= __put_user(0, &frame->uc.uc_flags);
 425         err |= __put_user(NULL, &frame->uc.uc_link);
 426         err |= __put_user((void *)current->sas_ss_sp,
 427                           &frame->uc.uc_stack.ss_sp);
 428         err |= __put_user(sas_ss_flags(regs->regs[15]),
 429                           &frame->uc.uc_stack.ss_flags);
 430         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 431         err |= setup_sigcontext(&frame->uc.uc_mcontext,
 432                                 regs, set->sig[0]);
 433         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 434
 435         /* Set up to return from userspace.  If provided, use a stub
 436            already in userspace.  */
 437         if (ka->sa.sa_flags & SA_RESTORER) {
 438                 regs->pr = (unsigned long) ka->sa.sa_restorer;
 439 #ifdef CONFIG_VSYSCALL
 440         } else if (likely(current->mm->context.vdso)) {
 441                 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
 442 #endif
 443         } else {
 444                 /* Generate return code (system call to rt_sigreturn) */
 445                 err |= __put_user(MOVW(7), &frame->retcode[0]);
 446                 err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
 447                 err |= __put_user(OR_R0_R0, &frame->retcode[2]);
 448                 err |= __put_user(OR_R0_R0, &frame->retcode[3]);
 449                 err |= __put_user(OR_R0_R0, &frame->retcode[4]);
 450                 err |= __put_user(OR_R0_R0, &frame->retcode[5]);
 451                 err |= __put_user(OR_R0_R0, &frame->retcode[6]);
 452                 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
 453                 regs->pr = (unsigned long) frame->retcode;
 454                 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
 455         }
 456
 457         if (err)
 458                 goto give_sigsegv;
 459
 460         /* Set up registers for signal handler */
 461         regs->regs[15] = (unsigned long) frame;
 462         regs->regs[4] = signal; /* Arg for signal handler */
 463         regs->regs[5] = (unsigned long) &frame->info;
 464         regs->regs[6] = (unsigned long) &frame->uc;
 465
 466         if (current->personality & FDPIC_FUNCPTRS) {
 467                 struct fdpic_func_descriptor __user *funcptr =
 468                         (struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
 469
 470                 err |= __get_user(regs->pc, &funcptr->text);
 471                 err |= __get_user(regs->regs[12], &funcptr->GOT);
 472         } else
 473                 regs->pc = (unsigned long)ka->sa.sa_handler;
 474
 475         if (err)
 476                 goto give_sigsegv;
 477
 478         set_fs(USER_DS);
 479
 480         pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
 481                  current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);
 482
 483         return 0;
 484
 485 give_sigsegv:
 486         force_sigsegv(sig, current);
 487         return -EFAULT;
 488 }
 489
 490 static inline void
 491 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs,
 492                        struct sigaction *sa)
 493 {
 494         /* If we're not from a syscall, bail out */
 495         if (regs->tra < 0)
 496                 return;
 497
 498         /* check for system call restart.. */
 499         switch (regs->regs[0]) {
 500                 case -ERESTART_RESTARTBLOCK:
 501                 case -ERESTARTNOHAND:
 502                 no_system_call_restart:
 503                         regs->regs[0] = -EINTR;
 504                         break;
 505
 506                 case -ERESTARTSYS:
 507                         if (!(sa->sa_flags & SA_RESTART))
 508                                 goto no_system_call_restart;
 509                 /* fallthrough */
 510                 case -ERESTARTNOINTR:
 511                         regs->regs[0] = save_r0;
 512                         regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
 513                         break;
 514         }
 515 }
 516
 517 /*
 518  * OK, we're invoking a handler
 519  */
 520 static void
 521 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,
 522               struct pt_regs *regs, unsigned int save_r0)
 523 {
 524         sigset_t *oldset = sigmask_to_save();
 525         int ret;
 526
 527         /* Set up the stack frame */
 528         if (ka->sa.sa_flags & SA_SIGINFO)
 529                 ret = setup_rt_frame(sig, ka, info, oldset, regs);
 530         else
 531                 ret = setup_frame(sig, ka, oldset, regs);
 532
 533         if (ret)
 534                 return;
 535         signal_delivered(sig, info, ka, regs,
 536                         test_thread_flag(TIF_SINGLESTEP));
 537 }
 538
 539 /*
 540  * Note that 'init' is a special process: it doesn't get signals it doesn't
 541  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 542  * mistake.
 543  *
 544  * Note that we go through the signals twice: once to check the signals that
 545  * the kernel can handle, and then we build all the user-level signal handling
 546  * stack-frames in one go after that.
 547  */
 548 static void do_signal(struct pt_regs *regs, unsigned int save_r0)
 549 {
 550         siginfo_t info;
 551         int signr;
 552         struct k_sigaction ka;
 553
 554         /*
 555          * We want the common case to go fast, which
 556          * is why we may in certain cases get here from
 557          * kernel mode. Just return without doing anything
 558          * if so.
 559          */
 560         if (!user_mode(regs))
 561                 return;
 562
 563         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 564         if (signr > 0) {
 565                 handle_syscall_restart(save_r0, regs, &ka.sa);
 566
 567                 /* Whee!  Actually deliver the signal.  */
 568                 handle_signal(signr, &ka, &info, regs, save_r0);
 569                 return;
 570         }
 571
 572         /* Did we come from a system call? */
 573         if (regs->tra >= 0) {
 574                 /* Restart the system call - no handlers present */
 575                 if (regs->regs[0] == -ERESTARTNOHAND ||
 576                     regs->regs[0] == -ERESTARTSYS ||
 577                     regs->regs[0] == -ERESTARTNOINTR) {
 578                         regs->regs[0] = save_r0;
 579                         regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
 580                 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {
 581                         regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
 582                         regs->regs[3] = __NR_restart_syscall;
 583                 }
 584         }
 585
 586         /*
 587          * If there's no signal to deliver, we just put the saved sigmask
 588          * back.
 589          */
 590         restore_saved_sigmask();
 591 }
 592
 593 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,
 594                                  unsigned long thread_info_flags)
 595 {
 596         /* deal with pending signal delivery */
 597         if (thread_info_flags & _TIF_SIGPENDING)
 598                 do_signal(regs, save_r0);
 599
 600         if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 601                 clear_thread_flag(TIF_NOTIFY_RESUME);
 602                 tracehook_notify_resume(regs);
 603         }
 604 }