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/freezer.h> 26 #include <linux/io.h> 27 #include <linux/tracehook.h> 28 #include <asm/system.h> 29 #include <asm/ucontext.h> 30 #include <asm/uaccess.h> 31 #include <asm/pgtable.h> 32 #include <asm/cacheflush.h> 33 #include <asm/syscalls.h> 34 #include <asm/fpu.h> 35 36 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 37 38 struct fdpic_func_descriptor { 39 unsigned long text; 40 unsigned long GOT; 41 }; 42 43 /* 44 * Atomically swap in the new signal mask, and wait for a signal. 45 */ 46 asmlinkage int 47 sys_sigsuspend(old_sigset_t mask, 48 unsigned long r5, unsigned long r6, unsigned long r7, 49 struct pt_regs __regs) 50 { 51 mask &= _BLOCKABLE; 52 spin_lock_irq(¤t->sighand->siglock); 53 current->saved_sigmask = current->blocked; 54 siginitset(¤t->blocked, mask); 55 recalc_sigpending(); 56 spin_unlock_irq(¤t->sighand->siglock); 57 58 current->state = TASK_INTERRUPTIBLE; 59 schedule(); 60 set_thread_flag(TIF_RESTORE_SIGMASK); 61 return -ERESTARTNOHAND; 62 } 63 64 asmlinkage int 65 sys_sigaction(int sig, const struct old_sigaction __user *act, 66 struct old_sigaction __user *oact) 67 { 68 struct k_sigaction new_ka, old_ka; 69 int ret; 70 71 if (act) { 72 old_sigset_t mask; 73 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 74 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 75 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) 76 return -EFAULT; 77 __get_user(new_ka.sa.sa_flags, &act->sa_flags); 78 __get_user(mask, &act->sa_mask); 79 siginitset(&new_ka.sa.sa_mask, mask); 80 } 81 82 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 83 84 if (!ret && oact) { 85 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 86 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 87 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) 88 return -EFAULT; 89 __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 90 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 91 } 92 93 return ret; 94 } 95 96 asmlinkage int 97 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 98 unsigned long r6, unsigned long r7, 99 struct pt_regs __regs) 100 { 101 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 102 103 return do_sigaltstack(uss, uoss, regs->regs[15]); 104 } 105 106 107 /* 108 * Do a signal return; undo the signal stack. 109 */ 110 111 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ 112 #if defined(CONFIG_CPU_SH2) 113 #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */ 114 #else 115 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */ 116 #endif 117 #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */ 118 119 struct sigframe 120 { 121 struct sigcontext sc; 122 unsigned long extramask[_NSIG_WORDS-1]; 123 u16 retcode[8]; 124 }; 125 126 struct rt_sigframe 127 { 128 struct siginfo info; 129 struct ucontext uc; 130 u16 retcode[8]; 131 }; 132 133 #ifdef CONFIG_SH_FPU 134 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc) 135 { 136 struct task_struct *tsk = current; 137 138 if (!(current_cpu_data.flags & CPU_HAS_FPU)) 139 return 0; 140 141 set_used_math(); 142 return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0], 143 sizeof(long)*(16*2+2)); 144 } 145 146 static inline int save_sigcontext_fpu(struct sigcontext __user *sc, 147 struct pt_regs *regs) 148 { 149 struct task_struct *tsk = current; 150 151 if (!(current_cpu_data.flags & CPU_HAS_FPU)) 152 return 0; 153 154 if (!used_math()) { 155 __put_user(0, &sc->sc_ownedfp); 156 return 0; 157 } 158 159 __put_user(1, &sc->sc_ownedfp); 160 161 /* This will cause a "finit" to be triggered by the next 162 attempted FPU operation by the 'current' process. 163 */ 164 clear_used_math(); 165 166 unlazy_fpu(tsk, regs); 167 return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard, 168 sizeof(long)*(16*2+2)); 169 } 170 #endif /* CONFIG_SH_FPU */ 171 172 static int 173 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) 174 { 175 unsigned int err = 0; 176 177 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) 178 COPY(regs[1]); 179 COPY(regs[2]); COPY(regs[3]); 180 COPY(regs[4]); COPY(regs[5]); 181 COPY(regs[6]); COPY(regs[7]); 182 COPY(regs[8]); COPY(regs[9]); 183 COPY(regs[10]); COPY(regs[11]); 184 COPY(regs[12]); COPY(regs[13]); 185 COPY(regs[14]); COPY(regs[15]); 186 COPY(gbr); COPY(mach); 187 COPY(macl); COPY(pr); 188 COPY(sr); COPY(pc); 189 #undef COPY 190 191 #ifdef CONFIG_SH_FPU 192 if (current_cpu_data.flags & CPU_HAS_FPU) { 193 int owned_fp; 194 struct task_struct *tsk = current; 195 196 regs->sr |= SR_FD; /* Release FPU */ 197 clear_fpu(tsk, regs); 198 clear_used_math(); 199 __get_user (owned_fp, &sc->sc_ownedfp); 200 if (owned_fp) 201 err |= restore_sigcontext_fpu(sc); 202 } 203 #endif 204 205 regs->tra = -1; /* disable syscall checks */ 206 err |= __get_user(*r0_p, &sc->sc_regs[0]); 207 return err; 208 } 209 210 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5, 211 unsigned long r6, unsigned long r7, 212 struct pt_regs __regs) 213 { 214 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 215 struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15]; 216 sigset_t set; 217 int r0; 218 219 /* Always make any pending restarted system calls return -EINTR */ 220 current_thread_info()->restart_block.fn = do_no_restart_syscall; 221 222 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 223 goto badframe; 224 225 if (__get_user(set.sig[0], &frame->sc.oldmask) 226 || (_NSIG_WORDS > 1 227 && __copy_from_user(&set.sig[1], &frame->extramask, 228 sizeof(frame->extramask)))) 229 goto badframe; 230 231 sigdelsetmask(&set, ~_BLOCKABLE); 232 233 spin_lock_irq(¤t->sighand->siglock); 234 current->blocked = set; 235 recalc_sigpending(); 236 spin_unlock_irq(¤t->sighand->siglock); 237 238 if (restore_sigcontext(regs, &frame->sc, &r0)) 239 goto badframe; 240 return r0; 241 242 badframe: 243 force_sig(SIGSEGV, current); 244 return 0; 245 } 246 247 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5, 248 unsigned long r6, unsigned long r7, 249 struct pt_regs __regs) 250 { 251 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 252 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15]; 253 sigset_t set; 254 int r0; 255 256 /* Always make any pending restarted system calls return -EINTR */ 257 current_thread_info()->restart_block.fn = do_no_restart_syscall; 258 259 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 260 goto badframe; 261 262 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 263 goto badframe; 264 265 sigdelsetmask(&set, ~_BLOCKABLE); 266 spin_lock_irq(¤t->sighand->siglock); 267 current->blocked = set; 268 recalc_sigpending(); 269 spin_unlock_irq(¤t->sighand->siglock); 270 271 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) 272 goto badframe; 273 274 if (do_sigaltstack(&frame->uc.uc_stack, NULL, 275 regs->regs[15]) == -EFAULT) 276 goto badframe; 277 278 return r0; 279 280 badframe: 281 force_sig(SIGSEGV, current); 282 return 0; 283 } 284 285 /* 286 * Set up a signal frame. 287 */ 288 289 static int 290 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 291 unsigned long mask) 292 { 293 int err = 0; 294 295 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) 296 COPY(regs[0]); COPY(regs[1]); 297 COPY(regs[2]); COPY(regs[3]); 298 COPY(regs[4]); COPY(regs[5]); 299 COPY(regs[6]); COPY(regs[7]); 300 COPY(regs[8]); COPY(regs[9]); 301 COPY(regs[10]); COPY(regs[11]); 302 COPY(regs[12]); COPY(regs[13]); 303 COPY(regs[14]); COPY(regs[15]); 304 COPY(gbr); COPY(mach); 305 COPY(macl); COPY(pr); 306 COPY(sr); COPY(pc); 307 #undef COPY 308 309 #ifdef CONFIG_SH_FPU 310 err |= save_sigcontext_fpu(sc, regs); 311 #endif 312 313 /* non-iBCS2 extensions.. */ 314 err |= __put_user(mask, &sc->oldmask); 315 316 return err; 317 } 318 319 /* 320 * Determine which stack to use.. 321 */ 322 static inline void __user * 323 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) 324 { 325 if (ka->sa.sa_flags & SA_ONSTACK) { 326 if (sas_ss_flags(sp) == 0) 327 sp = current->sas_ss_sp + current->sas_ss_size; 328 } 329 330 return (void __user *)((sp - frame_size) & -8ul); 331 } 332 333 /* These symbols are defined with the addresses in the vsyscall page. 334 See vsyscall-trapa.S. */ 335 extern void __user __kernel_sigreturn; 336 extern void __user __kernel_rt_sigreturn; 337 338 static int setup_frame(int sig, struct k_sigaction *ka, 339 sigset_t *set, struct pt_regs *regs) 340 { 341 struct sigframe __user *frame; 342 int err = 0; 343 int signal; 344 345 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); 346 347 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 348 goto give_sigsegv; 349 350 signal = current_thread_info()->exec_domain 351 && current_thread_info()->exec_domain->signal_invmap 352 && sig < 32 353 ? current_thread_info()->exec_domain->signal_invmap[sig] 354 : sig; 355 356 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); 357 358 if (_NSIG_WORDS > 1) 359 err |= __copy_to_user(frame->extramask, &set->sig[1], 360 sizeof(frame->extramask)); 361 362 /* Set up to return from userspace. If provided, use a stub 363 already in userspace. */ 364 if (ka->sa.sa_flags & SA_RESTORER) { 365 regs->pr = (unsigned long) ka->sa.sa_restorer; 366 #ifdef CONFIG_VSYSCALL 367 } else if (likely(current->mm->context.vdso)) { 368 regs->pr = VDSO_SYM(&__kernel_sigreturn); 369 #endif 370 } else { 371 /* Generate return code (system call to sigreturn) */ 372 err |= __put_user(MOVW(7), &frame->retcode[0]); 373 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 374 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 375 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 376 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 377 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 378 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 379 err |= __put_user((__NR_sigreturn), &frame->retcode[7]); 380 regs->pr = (unsigned long) frame->retcode; 381 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 382 } 383 384 if (err) 385 goto give_sigsegv; 386 387 /* Set up registers for signal handler */ 388 regs->regs[15] = (unsigned long) frame; 389 regs->regs[4] = signal; /* Arg for signal handler */ 390 regs->regs[5] = 0; 391 regs->regs[6] = (unsigned long) &frame->sc; 392 393 if (current->personality & FDPIC_FUNCPTRS) { 394 struct fdpic_func_descriptor __user *funcptr = 395 (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; 396 397 __get_user(regs->pc, &funcptr->text); 398 __get_user(regs->regs[12], &funcptr->GOT); 399 } else 400 regs->pc = (unsigned long)ka->sa.sa_handler; 401 402 set_fs(USER_DS); 403 404 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 405 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 406 407 return 0; 408 409 give_sigsegv: 410 force_sigsegv(sig, current); 411 return -EFAULT; 412 } 413 414 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 415 sigset_t *set, struct pt_regs *regs) 416 { 417 struct rt_sigframe __user *frame; 418 int err = 0; 419 int signal; 420 421 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); 422 423 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 424 goto give_sigsegv; 425 426 signal = current_thread_info()->exec_domain 427 && current_thread_info()->exec_domain->signal_invmap 428 && sig < 32 429 ? current_thread_info()->exec_domain->signal_invmap[sig] 430 : sig; 431 432 err |= copy_siginfo_to_user(&frame->info, info); 433 434 /* Create the ucontext. */ 435 err |= __put_user(0, &frame->uc.uc_flags); 436 err |= __put_user(NULL, &frame->uc.uc_link); 437 err |= __put_user((void *)current->sas_ss_sp, 438 &frame->uc.uc_stack.ss_sp); 439 err |= __put_user(sas_ss_flags(regs->regs[15]), 440 &frame->uc.uc_stack.ss_flags); 441 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); 442 err |= setup_sigcontext(&frame->uc.uc_mcontext, 443 regs, set->sig[0]); 444 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 445 446 /* Set up to return from userspace. If provided, use a stub 447 already in userspace. */ 448 if (ka->sa.sa_flags & SA_RESTORER) { 449 regs->pr = (unsigned long) ka->sa.sa_restorer; 450 #ifdef CONFIG_VSYSCALL 451 } else if (likely(current->mm->context.vdso)) { 452 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn); 453 #endif 454 } else { 455 /* Generate return code (system call to rt_sigreturn) */ 456 err |= __put_user(MOVW(7), &frame->retcode[0]); 457 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 458 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 459 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 460 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 461 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 462 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 463 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]); 464 regs->pr = (unsigned long) frame->retcode; 465 } 466 467 if (err) 468 goto give_sigsegv; 469 470 /* Set up registers for signal handler */ 471 regs->regs[15] = (unsigned long) frame; 472 regs->regs[4] = signal; /* Arg for signal handler */ 473 regs->regs[5] = (unsigned long) &frame->info; 474 regs->regs[6] = (unsigned long) &frame->uc; 475 476 if (current->personality & FDPIC_FUNCPTRS) { 477 struct fdpic_func_descriptor __user *funcptr = 478 (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; 479 480 __get_user(regs->pc, &funcptr->text); 481 __get_user(regs->regs[12], &funcptr->GOT); 482 } else 483 regs->pc = (unsigned long)ka->sa.sa_handler; 484 485 set_fs(USER_DS); 486 487 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 488 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 489 490 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 491 492 return 0; 493 494 give_sigsegv: 495 force_sigsegv(sig, current); 496 return -EFAULT; 497 } 498 499 static inline void 500 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs, 501 struct sigaction *sa) 502 { 503 /* If we're not from a syscall, bail out */ 504 if (regs->tra < 0) 505 return; 506 507 /* check for system call restart.. */ 508 switch (regs->regs[0]) { 509 case -ERESTART_RESTARTBLOCK: 510 case -ERESTARTNOHAND: 511 no_system_call_restart: 512 regs->regs[0] = -EINTR; 513 regs->sr |= 1; 514 break; 515 516 case -ERESTARTSYS: 517 if (!(sa->sa_flags & SA_RESTART)) 518 goto no_system_call_restart; 519 /* fallthrough */ 520 case -ERESTARTNOINTR: 521 regs->regs[0] = save_r0; 522 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 523 break; 524 } 525 } 526 527 /* 528 * OK, we're invoking a handler 529 */ 530 static int 531 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, 532 sigset_t *oldset, struct pt_regs *regs, unsigned int save_r0) 533 { 534 int ret; 535 536 537 /* Set up the stack frame */ 538 if (ka->sa.sa_flags & SA_SIGINFO) 539 ret = setup_rt_frame(sig, ka, info, oldset, regs); 540 else 541 ret = setup_frame(sig, ka, oldset, regs); 542 543 if (ka->sa.sa_flags & SA_ONESHOT) 544 ka->sa.sa_handler = SIG_DFL; 545 546 if (ret == 0) { 547 spin_lock_irq(¤t->sighand->siglock); 548 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); 549 if (!(ka->sa.sa_flags & SA_NODEFER)) 550 sigaddset(¤t->blocked,sig); 551 recalc_sigpending(); 552 spin_unlock_irq(¤t->sighand->siglock); 553 } 554 555 return ret; 556 } 557 558 /* 559 * Note that 'init' is a special process: it doesn't get signals it doesn't 560 * want to handle. Thus you cannot kill init even with a SIGKILL even by 561 * mistake. 562 * 563 * Note that we go through the signals twice: once to check the signals that 564 * the kernel can handle, and then we build all the user-level signal handling 565 * stack-frames in one go after that. 566 */ 567 static void do_signal(struct pt_regs *regs, unsigned int save_r0) 568 { 569 siginfo_t info; 570 int signr; 571 struct k_sigaction ka; 572 sigset_t *oldset; 573 574 /* 575 * We want the common case to go fast, which 576 * is why we may in certain cases get here from 577 * kernel mode. Just return without doing anything 578 * if so. 579 */ 580 if (!user_mode(regs)) 581 return; 582 583 if (try_to_freeze()) 584 goto no_signal; 585 586 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 587 oldset = ¤t->saved_sigmask; 588 else 589 oldset = ¤t->blocked; 590 591 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 592 if (signr > 0) { 593 if (regs->sr & 1) 594 handle_syscall_restart(save_r0, regs, &ka.sa); 595 596 /* Whee! Actually deliver the signal. */ 597 if (handle_signal(signr, &ka, &info, oldset, 598 regs, save_r0) == 0) { 599 /* a signal was successfully delivered; the saved 600 * sigmask will have been stored in the signal frame, 601 * and will be restored by sigreturn, so we can simply 602 * clear the TIF_RESTORE_SIGMASK flag */ 603 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 604 clear_thread_flag(TIF_RESTORE_SIGMASK); 605 606 tracehook_signal_handler(signr, &info, &ka, regs, 607 test_thread_flag(TIF_SINGLESTEP)); 608 } 609 610 return; 611 } 612 613 no_signal: 614 /* Did we come from a system call? */ 615 if (regs->tra >= 0) { 616 /* Restart the system call - no handlers present */ 617 if (regs->regs[0] == -ERESTARTNOHAND || 618 regs->regs[0] == -ERESTARTSYS || 619 regs->regs[0] == -ERESTARTNOINTR) { 620 regs->regs[0] = save_r0; 621 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 622 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { 623 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 624 regs->regs[3] = __NR_restart_syscall; 625 } 626 } 627 628 /* if there's no signal to deliver, we just put the saved sigmask 629 * back */ 630 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 631 clear_thread_flag(TIF_RESTORE_SIGMASK); 632 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 633 } 634 } 635 636 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, 637 unsigned long thread_info_flags) 638 { 639 /* deal with pending signal delivery */ 640 if (thread_info_flags & _TIF_SIGPENDING) 641 do_signal(regs, save_r0); 642 643 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 644 clear_thread_flag(TIF_NOTIFY_RESUME); 645 tracehook_notify_resume(regs); 646 } 647 } 648