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