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 <asm/system.h> 28 #include <asm/ucontext.h> 29 #include <asm/uaccess.h> 30 #include <asm/pgtable.h> 31 #include <asm/cacheflush.h> 32 #include <asm/fpu.h> 33 34 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 35 36 struct fdpic_func_descriptor { 37 unsigned long text; 38 unsigned long GOT; 39 }; 40 41 /* 42 * Atomically swap in the new signal mask, and wait for a signal. 43 */ 44 asmlinkage int 45 sys_sigsuspend(old_sigset_t mask, 46 unsigned long r5, unsigned long r6, unsigned long r7, 47 struct pt_regs __regs) 48 { 49 mask &= _BLOCKABLE; 50 spin_lock_irq(¤t->sighand->siglock); 51 current->saved_sigmask = current->blocked; 52 siginitset(¤t->blocked, mask); 53 recalc_sigpending(); 54 spin_unlock_irq(¤t->sighand->siglock); 55 56 current->state = TASK_INTERRUPTIBLE; 57 schedule(); 58 set_thread_flag(TIF_RESTORE_SIGMASK); 59 return -ERESTARTNOHAND; 60 } 61 62 asmlinkage int 63 sys_sigaction(int sig, const struct old_sigaction __user *act, 64 struct old_sigaction __user *oact) 65 { 66 struct k_sigaction new_ka, old_ka; 67 int ret; 68 69 if (act) { 70 old_sigset_t mask; 71 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 72 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 73 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) 74 return -EFAULT; 75 __get_user(new_ka.sa.sa_flags, &act->sa_flags); 76 __get_user(mask, &act->sa_mask); 77 siginitset(&new_ka.sa.sa_mask, mask); 78 } 79 80 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 81 82 if (!ret && oact) { 83 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 84 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 85 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) 86 return -EFAULT; 87 __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 88 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 89 } 90 91 return ret; 92 } 93 94 asmlinkage int 95 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 96 unsigned long r6, unsigned long r7, 97 struct pt_regs __regs) 98 { 99 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 100 101 return do_sigaltstack(uss, uoss, regs->regs[15]); 102 } 103 104 105 /* 106 * Do a signal return; undo the signal stack. 107 */ 108 109 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ 110 #if defined(CONFIG_CPU_SH2) 111 #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */ 112 #else 113 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */ 114 #endif 115 #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */ 116 117 struct sigframe 118 { 119 struct sigcontext sc; 120 unsigned long extramask[_NSIG_WORDS-1]; 121 u16 retcode[8]; 122 }; 123 124 struct rt_sigframe 125 { 126 struct siginfo info; 127 struct ucontext uc; 128 u16 retcode[8]; 129 }; 130 131 #ifdef CONFIG_SH_FPU 132 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc) 133 { 134 struct task_struct *tsk = current; 135 136 if (!(current_cpu_data.flags & CPU_HAS_FPU)) 137 return 0; 138 139 set_used_math(); 140 return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0], 141 sizeof(long)*(16*2+2)); 142 } 143 144 static inline int save_sigcontext_fpu(struct sigcontext __user *sc, 145 struct pt_regs *regs) 146 { 147 struct task_struct *tsk = current; 148 149 if (!(current_cpu_data.flags & CPU_HAS_FPU)) 150 return 0; 151 152 if (!used_math()) { 153 __put_user(0, &sc->sc_ownedfp); 154 return 0; 155 } 156 157 __put_user(1, &sc->sc_ownedfp); 158 159 /* This will cause a "finit" to be triggered by the next 160 attempted FPU operation by the 'current' process. 161 */ 162 clear_used_math(); 163 164 unlazy_fpu(tsk, regs); 165 return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard, 166 sizeof(long)*(16*2+2)); 167 } 168 #endif /* CONFIG_SH_FPU */ 169 170 static int 171 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) 172 { 173 unsigned int err = 0; 174 175 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) 176 COPY(regs[1]); 177 COPY(regs[2]); COPY(regs[3]); 178 COPY(regs[4]); COPY(regs[5]); 179 COPY(regs[6]); COPY(regs[7]); 180 COPY(regs[8]); COPY(regs[9]); 181 COPY(regs[10]); COPY(regs[11]); 182 COPY(regs[12]); COPY(regs[13]); 183 COPY(regs[14]); COPY(regs[15]); 184 COPY(gbr); COPY(mach); 185 COPY(macl); COPY(pr); 186 COPY(sr); COPY(pc); 187 #undef COPY 188 189 #ifdef CONFIG_SH_FPU 190 if (current_cpu_data.flags & CPU_HAS_FPU) { 191 int owned_fp; 192 struct task_struct *tsk = current; 193 194 regs->sr |= SR_FD; /* Release FPU */ 195 clear_fpu(tsk, regs); 196 clear_used_math(); 197 __get_user (owned_fp, &sc->sc_ownedfp); 198 if (owned_fp) 199 err |= restore_sigcontext_fpu(sc); 200 } 201 #endif 202 203 regs->tra = -1; /* disable syscall checks */ 204 err |= __get_user(*r0_p, &sc->sc_regs[0]); 205 return err; 206 } 207 208 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5, 209 unsigned long r6, unsigned long r7, 210 struct pt_regs __regs) 211 { 212 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 213 struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15]; 214 sigset_t set; 215 int r0; 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 sigdelsetmask(&set, ~_BLOCKABLE); 227 228 spin_lock_irq(¤t->sighand->siglock); 229 current->blocked = set; 230 recalc_sigpending(); 231 spin_unlock_irq(¤t->sighand->siglock); 232 233 if (restore_sigcontext(regs, &frame->sc, &r0)) 234 goto badframe; 235 return r0; 236 237 badframe: 238 force_sig(SIGSEGV, current); 239 return 0; 240 } 241 242 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5, 243 unsigned long r6, unsigned long r7, 244 struct pt_regs __regs) 245 { 246 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 247 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15]; 248 sigset_t set; 249 stack_t st; 250 int r0; 251 252 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 253 goto badframe; 254 255 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 256 goto badframe; 257 258 sigdelsetmask(&set, ~_BLOCKABLE); 259 spin_lock_irq(¤t->sighand->siglock); 260 current->blocked = set; 261 recalc_sigpending(); 262 spin_unlock_irq(¤t->sighand->siglock); 263 264 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) 265 goto badframe; 266 267 if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st))) 268 goto badframe; 269 /* It is more difficult to avoid calling this function than to 270 call it and ignore errors. */ 271 do_sigaltstack((const stack_t __user *)&st, NULL, (unsigned long)frame); 272 273 return r0; 274 275 badframe: 276 force_sig(SIGSEGV, current); 277 return 0; 278 } 279 280 /* 281 * Set up a signal frame. 282 */ 283 284 static int 285 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 286 unsigned long mask) 287 { 288 int err = 0; 289 290 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) 291 COPY(regs[0]); COPY(regs[1]); 292 COPY(regs[2]); COPY(regs[3]); 293 COPY(regs[4]); COPY(regs[5]); 294 COPY(regs[6]); COPY(regs[7]); 295 COPY(regs[8]); COPY(regs[9]); 296 COPY(regs[10]); COPY(regs[11]); 297 COPY(regs[12]); COPY(regs[13]); 298 COPY(regs[14]); COPY(regs[15]); 299 COPY(gbr); COPY(mach); 300 COPY(macl); COPY(pr); 301 COPY(sr); COPY(pc); 302 #undef COPY 303 304 #ifdef CONFIG_SH_FPU 305 err |= save_sigcontext_fpu(sc, regs); 306 #endif 307 308 /* non-iBCS2 extensions.. */ 309 err |= __put_user(mask, &sc->oldmask); 310 311 return err; 312 } 313 314 /* 315 * Determine which stack to use.. 316 */ 317 static inline void __user * 318 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) 319 { 320 if (ka->sa.sa_flags & SA_ONSTACK) { 321 if (sas_ss_flags(sp) == 0) 322 sp = current->sas_ss_sp + current->sas_ss_size; 323 } 324 325 return (void __user *)((sp - frame_size) & -8ul); 326 } 327 328 /* These symbols are defined with the addresses in the vsyscall page. 329 See vsyscall-trapa.S. */ 330 extern void __user __kernel_sigreturn; 331 extern void __user __kernel_rt_sigreturn; 332 333 static int setup_frame(int sig, struct k_sigaction *ka, 334 sigset_t *set, struct pt_regs *regs) 335 { 336 struct sigframe __user *frame; 337 int err = 0; 338 int signal; 339 340 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); 341 342 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 343 goto give_sigsegv; 344 345 signal = current_thread_info()->exec_domain 346 && current_thread_info()->exec_domain->signal_invmap 347 && sig < 32 348 ? current_thread_info()->exec_domain->signal_invmap[sig] 349 : sig; 350 351 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); 352 353 if (_NSIG_WORDS > 1) 354 err |= __copy_to_user(frame->extramask, &set->sig[1], 355 sizeof(frame->extramask)); 356 357 /* Set up to return from userspace. If provided, use a stub 358 already in userspace. */ 359 if (ka->sa.sa_flags & SA_RESTORER) { 360 regs->pr = (unsigned long) ka->sa.sa_restorer; 361 #ifdef CONFIG_VSYSCALL 362 } else if (likely(current->mm->context.vdso)) { 363 regs->pr = VDSO_SYM(&__kernel_sigreturn); 364 #endif 365 } else { 366 /* Generate return code (system call to sigreturn) */ 367 err |= __put_user(MOVW(7), &frame->retcode[0]); 368 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 369 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 370 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 371 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 372 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 373 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 374 err |= __put_user((__NR_sigreturn), &frame->retcode[7]); 375 regs->pr = (unsigned long) frame->retcode; 376 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 377 } 378 379 if (err) 380 goto give_sigsegv; 381 382 /* Set up registers for signal handler */ 383 regs->regs[15] = (unsigned long) frame; 384 regs->regs[4] = signal; /* Arg for signal handler */ 385 regs->regs[5] = 0; 386 regs->regs[6] = (unsigned long) &frame->sc; 387 388 if (current->personality & FDPIC_FUNCPTRS) { 389 struct fdpic_func_descriptor __user *funcptr = 390 (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; 391 392 __get_user(regs->pc, &funcptr->text); 393 __get_user(regs->regs[12], &funcptr->GOT); 394 } else 395 regs->pc = (unsigned long)ka->sa.sa_handler; 396 397 set_fs(USER_DS); 398 399 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 400 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 401 402 return 0; 403 404 give_sigsegv: 405 force_sigsegv(sig, current); 406 return -EFAULT; 407 } 408 409 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 410 sigset_t *set, struct pt_regs *regs) 411 { 412 struct rt_sigframe __user *frame; 413 int err = 0; 414 int signal; 415 416 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); 417 418 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 419 goto give_sigsegv; 420 421 signal = current_thread_info()->exec_domain 422 && current_thread_info()->exec_domain->signal_invmap 423 && sig < 32 424 ? current_thread_info()->exec_domain->signal_invmap[sig] 425 : sig; 426 427 err |= copy_siginfo_to_user(&frame->info, info); 428 429 /* Create the ucontext. */ 430 err |= __put_user(0, &frame->uc.uc_flags); 431 err |= __put_user(0, &frame->uc.uc_link); 432 err |= __put_user((void *)current->sas_ss_sp, 433 &frame->uc.uc_stack.ss_sp); 434 err |= __put_user(sas_ss_flags(regs->regs[15]), 435 &frame->uc.uc_stack.ss_flags); 436 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); 437 err |= setup_sigcontext(&frame->uc.uc_mcontext, 438 regs, set->sig[0]); 439 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 440 441 /* Set up to return from userspace. If provided, use a stub 442 already in userspace. */ 443 if (ka->sa.sa_flags & SA_RESTORER) { 444 regs->pr = (unsigned long) ka->sa.sa_restorer; 445 #ifdef CONFIG_VSYSCALL 446 } else if (likely(current->mm->context.vdso)) { 447 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn); 448 #endif 449 } else { 450 /* Generate return code (system call to rt_sigreturn) */ 451 err |= __put_user(MOVW(7), &frame->retcode[0]); 452 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 453 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 454 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 455 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 456 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 457 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 458 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]); 459 regs->pr = (unsigned long) frame->retcode; 460 } 461 462 if (err) 463 goto give_sigsegv; 464 465 /* Set up registers for signal handler */ 466 regs->regs[15] = (unsigned long) frame; 467 regs->regs[4] = signal; /* Arg for signal handler */ 468 regs->regs[5] = (unsigned long) &frame->info; 469 regs->regs[6] = (unsigned long) &frame->uc; 470 471 if (current->personality & FDPIC_FUNCPTRS) { 472 struct fdpic_func_descriptor __user *funcptr = 473 (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; 474 475 __get_user(regs->pc, &funcptr->text); 476 __get_user(regs->regs[12], &funcptr->GOT); 477 } else 478 regs->pc = (unsigned long)ka->sa.sa_handler; 479 480 set_fs(USER_DS); 481 482 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 483 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 484 485 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 486 487 return 0; 488 489 give_sigsegv: 490 force_sigsegv(sig, current); 491 return -EFAULT; 492 } 493 494 /* 495 * OK, we're invoking a handler 496 */ 497 498 static int 499 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, 500 sigset_t *oldset, struct pt_regs *regs, unsigned int save_r0) 501 { 502 int ret; 503 504 /* Are we from a system call? */ 505 if (regs->tra >= 0) { 506 /* If so, check system call restarting.. */ 507 switch (regs->regs[0]) { 508 case -ERESTART_RESTARTBLOCK: 509 case -ERESTARTNOHAND: 510 regs->regs[0] = -EINTR; 511 break; 512 513 case -ERESTARTSYS: 514 if (!(ka->sa.sa_flags & SA_RESTART)) { 515 regs->regs[0] = -EINTR; 516 break; 517 } 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 } 593 594 return; 595 } 596 597 no_signal: 598 /* Did we come from a system call? */ 599 if (regs->tra >= 0) { 600 /* Restart the system call - no handlers present */ 601 if (regs->regs[0] == -ERESTARTNOHAND || 602 regs->regs[0] == -ERESTARTSYS || 603 regs->regs[0] == -ERESTARTNOINTR) { 604 regs->regs[0] = save_r0; 605 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 606 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { 607 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 608 regs->regs[3] = __NR_restart_syscall; 609 } 610 } 611 612 /* if there's no signal to deliver, we just put the saved sigmask 613 * back */ 614 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 615 clear_thread_flag(TIF_RESTORE_SIGMASK); 616 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 617 } 618 } 619 620 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, 621 __u32 thread_info_flags) 622 { 623 /* deal with pending signal delivery */ 624 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)) 625 do_signal(regs, save_r0); 626 } 627