1 /* 2 * Architecture-specific signal handling support. 3 * 4 * Copyright (C) 1999-2004 Hewlett-Packard Co 5 * David Mosberger-Tang <davidm@hpl.hp.com> 6 * 7 * Derived from i386 and Alpha versions. 8 */ 9 10 #include <linux/errno.h> 11 #include <linux/kernel.h> 12 #include <linux/mm.h> 13 #include <linux/ptrace.h> 14 #include <linux/tracehook.h> 15 #include <linux/sched.h> 16 #include <linux/signal.h> 17 #include <linux/smp.h> 18 #include <linux/stddef.h> 19 #include <linux/tty.h> 20 #include <linux/binfmts.h> 21 #include <linux/unistd.h> 22 #include <linux/wait.h> 23 24 #include <asm/intrinsics.h> 25 #include <asm/uaccess.h> 26 #include <asm/rse.h> 27 #include <asm/sigcontext.h> 28 29 #include "sigframe.h" 30 31 #define DEBUG_SIG 0 32 #define STACK_ALIGN 16 /* minimal alignment for stack pointer */ 33 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 34 35 #if _NSIG_WORDS > 1 36 # define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t)) 37 # define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t)) 38 #else 39 # define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0]) 40 # define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0]) 41 #endif 42 43 asmlinkage long 44 sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2, 45 long arg3, long arg4, long arg5, long arg6, long arg7, 46 struct pt_regs regs) 47 { 48 return do_sigaltstack(uss, uoss, regs.r12); 49 } 50 51 static long 52 restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr) 53 { 54 unsigned long ip, flags, nat, um, cfm, rsc; 55 long err; 56 57 /* Always make any pending restarted system calls return -EINTR */ 58 current_thread_info()->restart_block.fn = do_no_restart_syscall; 59 60 /* restore scratch that always needs gets updated during signal delivery: */ 61 err = __get_user(flags, &sc->sc_flags); 62 err |= __get_user(nat, &sc->sc_nat); 63 err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */ 64 err |= __get_user(cfm, &sc->sc_cfm); 65 err |= __get_user(um, &sc->sc_um); /* user mask */ 66 err |= __get_user(rsc, &sc->sc_ar_rsc); 67 err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat); 68 err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); 69 err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs); 70 err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */ 71 err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */ 72 err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */ 73 err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */ 74 err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */ 75 err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8); /* r12-r13 */ 76 err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8); /* r15 */ 77 78 scr->pt.cr_ifs = cfm | (1UL << 63); 79 scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */ 80 81 /* establish new instruction pointer: */ 82 scr->pt.cr_iip = ip & ~0x3UL; 83 ia64_psr(&scr->pt)->ri = ip & 0x3; 84 scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM); 85 86 scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat); 87 88 if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) { 89 /* Restore most scratch-state only when not in syscall. */ 90 err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */ 91 err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */ 92 err |= __get_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */ 93 err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */ 94 err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8); /* r2-r3 */ 95 err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */ 96 } 97 98 if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) { 99 struct ia64_psr *psr = ia64_psr(&scr->pt); 100 101 err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16); 102 psr->mfh = 0; /* drop signal handler's fph contents... */ 103 preempt_disable(); 104 if (psr->dfh) 105 ia64_drop_fpu(current); 106 else { 107 /* We already own the local fph, otherwise psr->dfh wouldn't be 0. */ 108 __ia64_load_fpu(current->thread.fph); 109 ia64_set_local_fpu_owner(current); 110 } 111 preempt_enable(); 112 } 113 return err; 114 } 115 116 int 117 copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from) 118 { 119 if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t))) 120 return -EFAULT; 121 if (from->si_code < 0) { 122 if (__copy_to_user(to, from, sizeof(siginfo_t))) 123 return -EFAULT; 124 return 0; 125 } else { 126 int err; 127 128 /* 129 * If you change siginfo_t structure, please be sure this code is fixed 130 * accordingly. It should never copy any pad contained in the structure 131 * to avoid security leaks, but must copy the generic 3 ints plus the 132 * relevant union member. 133 */ 134 err = __put_user(from->si_signo, &to->si_signo); 135 err |= __put_user(from->si_errno, &to->si_errno); 136 err |= __put_user((short)from->si_code, &to->si_code); 137 switch (from->si_code >> 16) { 138 case __SI_FAULT >> 16: 139 err |= __put_user(from->si_flags, &to->si_flags); 140 err |= __put_user(from->si_isr, &to->si_isr); 141 case __SI_POLL >> 16: 142 err |= __put_user(from->si_addr, &to->si_addr); 143 err |= __put_user(from->si_imm, &to->si_imm); 144 break; 145 case __SI_TIMER >> 16: 146 err |= __put_user(from->si_tid, &to->si_tid); 147 err |= __put_user(from->si_overrun, &to->si_overrun); 148 err |= __put_user(from->si_ptr, &to->si_ptr); 149 break; 150 case __SI_RT >> 16: /* Not generated by the kernel as of now. */ 151 case __SI_MESGQ >> 16: 152 err |= __put_user(from->si_uid, &to->si_uid); 153 err |= __put_user(from->si_pid, &to->si_pid); 154 err |= __put_user(from->si_ptr, &to->si_ptr); 155 break; 156 case __SI_CHLD >> 16: 157 err |= __put_user(from->si_utime, &to->si_utime); 158 err |= __put_user(from->si_stime, &to->si_stime); 159 err |= __put_user(from->si_status, &to->si_status); 160 default: 161 err |= __put_user(from->si_uid, &to->si_uid); 162 err |= __put_user(from->si_pid, &to->si_pid); 163 break; 164 } 165 return err; 166 } 167 } 168 169 long 170 ia64_rt_sigreturn (struct sigscratch *scr) 171 { 172 extern char ia64_strace_leave_kernel, ia64_leave_kernel; 173 struct sigcontext __user *sc; 174 struct siginfo si; 175 sigset_t set; 176 long retval; 177 178 sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc; 179 180 /* 181 * When we return to the previously executing context, r8 and r10 have already 182 * been setup the way we want them. Indeed, if the signal wasn't delivered while 183 * in a system call, we must not touch r8 or r10 as otherwise user-level state 184 * could be corrupted. 185 */ 186 retval = (long) &ia64_leave_kernel; 187 if (test_thread_flag(TIF_SYSCALL_TRACE) 188 || test_thread_flag(TIF_SYSCALL_AUDIT)) 189 /* 190 * strace expects to be notified after sigreturn returns even though the 191 * context to which we return may not be in the middle of a syscall. 192 * Thus, the return-value that strace displays for sigreturn is 193 * meaningless. 194 */ 195 retval = (long) &ia64_strace_leave_kernel; 196 197 if (!access_ok(VERIFY_READ, sc, sizeof(*sc))) 198 goto give_sigsegv; 199 200 if (GET_SIGSET(&set, &sc->sc_mask)) 201 goto give_sigsegv; 202 203 sigdelsetmask(&set, ~_BLOCKABLE); 204 205 spin_lock_irq(¤t->sighand->siglock); 206 { 207 current->blocked = set; 208 recalc_sigpending(); 209 } 210 spin_unlock_irq(¤t->sighand->siglock); 211 212 if (restore_sigcontext(sc, scr)) 213 goto give_sigsegv; 214 215 #if DEBUG_SIG 216 printk("SIG return (%s:%d): sp=%lx ip=%lx\n", 217 current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip); 218 #endif 219 /* 220 * It is more difficult to avoid calling this function than to 221 * call it and ignore errors. 222 */ 223 do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12); 224 return retval; 225 226 give_sigsegv: 227 si.si_signo = SIGSEGV; 228 si.si_errno = 0; 229 si.si_code = SI_KERNEL; 230 si.si_pid = task_pid_vnr(current); 231 si.si_uid = current_uid(); 232 si.si_addr = sc; 233 force_sig_info(SIGSEGV, &si, current); 234 return retval; 235 } 236 237 /* 238 * This does just the minimum required setup of sigcontext. 239 * Specifically, it only installs data that is either not knowable at 240 * the user-level or that gets modified before execution in the 241 * trampoline starts. Everything else is done at the user-level. 242 */ 243 static long 244 setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr) 245 { 246 unsigned long flags = 0, ifs, cfm, nat; 247 long err = 0; 248 249 ifs = scr->pt.cr_ifs; 250 251 if (on_sig_stack((unsigned long) sc)) 252 flags |= IA64_SC_FLAG_ONSTACK; 253 if ((ifs & (1UL << 63)) == 0) 254 /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */ 255 flags |= IA64_SC_FLAG_IN_SYSCALL; 256 cfm = ifs & ((1UL << 38) - 1); 257 ia64_flush_fph(current); 258 if ((current->thread.flags & IA64_THREAD_FPH_VALID)) { 259 flags |= IA64_SC_FLAG_FPH_VALID; 260 err = __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16); 261 } 262 263 nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat); 264 265 err |= __put_user(flags, &sc->sc_flags); 266 err |= __put_user(nat, &sc->sc_nat); 267 err |= PUT_SIGSET(mask, &sc->sc_mask); 268 err |= __put_user(cfm, &sc->sc_cfm); 269 err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um); 270 err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc); 271 err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */ 272 err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */ 273 err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs); 274 err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */ 275 err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */ 276 err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */ 277 err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8); /* r1 */ 278 err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */ 279 err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8); /* r12-r13 */ 280 err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8); /* r15 */ 281 err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip); 282 283 if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) { 284 /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */ 285 err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */ 286 err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */ 287 err |= __put_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */ 288 err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */ 289 err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8); /* r2-r3 */ 290 err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */ 291 } 292 return err; 293 } 294 295 /* 296 * Check whether the register-backing store is already on the signal stack. 297 */ 298 static inline int 299 rbs_on_sig_stack (unsigned long bsp) 300 { 301 return (bsp - current->sas_ss_sp < current->sas_ss_size); 302 } 303 304 static long 305 force_sigsegv_info (int sig, void __user *addr) 306 { 307 unsigned long flags; 308 struct siginfo si; 309 310 if (sig == SIGSEGV) { 311 /* 312 * Acquiring siglock around the sa_handler-update is almost 313 * certainly overkill, but this isn't a 314 * performance-critical path and I'd rather play it safe 315 * here than having to debug a nasty race if and when 316 * something changes in kernel/signal.c that would make it 317 * no longer safe to modify sa_handler without holding the 318 * lock. 319 */ 320 spin_lock_irqsave(¤t->sighand->siglock, flags); 321 current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; 322 spin_unlock_irqrestore(¤t->sighand->siglock, flags); 323 } 324 si.si_signo = SIGSEGV; 325 si.si_errno = 0; 326 si.si_code = SI_KERNEL; 327 si.si_pid = task_pid_vnr(current); 328 si.si_uid = current_uid(); 329 si.si_addr = addr; 330 force_sig_info(SIGSEGV, &si, current); 331 return 0; 332 } 333 334 static long 335 setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, 336 struct sigscratch *scr) 337 { 338 extern char __kernel_sigtramp[]; 339 unsigned long tramp_addr, new_rbs = 0, new_sp; 340 struct sigframe __user *frame; 341 long err; 342 343 new_sp = scr->pt.r12; 344 tramp_addr = (unsigned long) __kernel_sigtramp; 345 if (ka->sa.sa_flags & SA_ONSTACK) { 346 int onstack = sas_ss_flags(new_sp); 347 348 if (onstack == 0) { 349 new_sp = current->sas_ss_sp + current->sas_ss_size; 350 /* 351 * We need to check for the register stack being on the 352 * signal stack separately, because it's switched 353 * separately (memory stack is switched in the kernel, 354 * register stack is switched in the signal trampoline). 355 */ 356 if (!rbs_on_sig_stack(scr->pt.ar_bspstore)) 357 new_rbs = ALIGN(current->sas_ss_sp, 358 sizeof(long)); 359 } else if (onstack == SS_ONSTACK) { 360 unsigned long check_sp; 361 362 /* 363 * If we are on the alternate signal stack and would 364 * overflow it, don't. Return an always-bogus address 365 * instead so we will die with SIGSEGV. 366 */ 367 check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN; 368 if (!likely(on_sig_stack(check_sp))) 369 return force_sigsegv_info(sig, (void __user *) 370 check_sp); 371 } 372 } 373 frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN); 374 375 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 376 return force_sigsegv_info(sig, frame); 377 378 err = __put_user(sig, &frame->arg0); 379 err |= __put_user(&frame->info, &frame->arg1); 380 err |= __put_user(&frame->sc, &frame->arg2); 381 err |= __put_user(new_rbs, &frame->sc.sc_rbs_base); 382 err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */ 383 err |= __put_user(ka->sa.sa_handler, &frame->handler); 384 385 err |= copy_siginfo_to_user(&frame->info, info); 386 387 err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp); 388 err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size); 389 err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags); 390 err |= setup_sigcontext(&frame->sc, set, scr); 391 392 if (unlikely(err)) 393 return force_sigsegv_info(sig, frame); 394 395 scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */ 396 scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */ 397 scr->pt.cr_iip = tramp_addr; 398 ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */ 399 ia64_psr(&scr->pt)->be = 0; /* force little-endian byte-order */ 400 /* 401 * Force the interruption function mask to zero. This has no effect when a 402 * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is 403 * ignored), but it has the desirable effect of making it possible to deliver a 404 * signal with an incomplete register frame (which happens when a mandatory RSE 405 * load faults). Furthermore, it has no negative effect on the getting the user's 406 * dirty partition preserved, because that's governed by scr->pt.loadrs. 407 */ 408 scr->pt.cr_ifs = (1UL << 63); 409 410 /* 411 * Note: this affects only the NaT bits of the scratch regs (the ones saved in 412 * pt_regs), which is exactly what we want. 413 */ 414 scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */ 415 416 #if DEBUG_SIG 417 printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n", 418 current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler); 419 #endif 420 return 1; 421 } 422 423 static long 424 handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, 425 struct sigscratch *scr) 426 { 427 if (!setup_frame(sig, ka, info, oldset, scr)) 428 return 0; 429 430 spin_lock_irq(¤t->sighand->siglock); 431 sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); 432 if (!(ka->sa.sa_flags & SA_NODEFER)) 433 sigaddset(¤t->blocked, sig); 434 recalc_sigpending(); 435 spin_unlock_irq(¤t->sighand->siglock); 436 437 /* 438 * Let tracing know that we've done the handler setup. 439 */ 440 tracehook_signal_handler(sig, info, ka, &scr->pt, 441 test_thread_flag(TIF_SINGLESTEP)); 442 443 return 1; 444 } 445 446 /* 447 * Note that `init' is a special process: it doesn't get signals it doesn't want to 448 * handle. Thus you cannot kill init even with a SIGKILL even by mistake. 449 */ 450 void 451 ia64_do_signal (struct sigscratch *scr, long in_syscall) 452 { 453 struct k_sigaction ka; 454 sigset_t *oldset; 455 siginfo_t info; 456 long restart = in_syscall; 457 long errno = scr->pt.r8; 458 459 /* 460 * In the ia64_leave_kernel code path, we want the common case to go fast, which 461 * is why we may in certain cases get here from kernel mode. Just return without 462 * doing anything if so. 463 */ 464 if (!user_mode(&scr->pt)) 465 return; 466 467 if (current_thread_info()->status & TS_RESTORE_SIGMASK) 468 oldset = ¤t->saved_sigmask; 469 else 470 oldset = ¤t->blocked; 471 472 /* 473 * This only loops in the rare cases of handle_signal() failing, in which case we 474 * need to push through a forced SIGSEGV. 475 */ 476 while (1) { 477 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL); 478 479 /* 480 * get_signal_to_deliver() may have run a debugger (via notify_parent()) 481 * and the debugger may have modified the state (e.g., to arrange for an 482 * inferior call), thus it's important to check for restarting _after_ 483 * get_signal_to_deliver(). 484 */ 485 if ((long) scr->pt.r10 != -1) 486 /* 487 * A system calls has to be restarted only if one of the error codes 488 * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10 489 * isn't -1 then r8 doesn't hold an error code and we don't need to 490 * restart the syscall, so we can clear the "restart" flag here. 491 */ 492 restart = 0; 493 494 if (signr <= 0) 495 break; 496 497 if (unlikely(restart)) { 498 switch (errno) { 499 case ERESTART_RESTARTBLOCK: 500 case ERESTARTNOHAND: 501 scr->pt.r8 = EINTR; 502 /* note: scr->pt.r10 is already -1 */ 503 break; 504 505 case ERESTARTSYS: 506 if ((ka.sa.sa_flags & SA_RESTART) == 0) { 507 scr->pt.r8 = EINTR; 508 /* note: scr->pt.r10 is already -1 */ 509 break; 510 } 511 case ERESTARTNOINTR: 512 ia64_decrement_ip(&scr->pt); 513 restart = 0; /* don't restart twice if handle_signal() fails... */ 514 } 515 } 516 517 /* 518 * Whee! Actually deliver the signal. If the delivery failed, we need to 519 * continue to iterate in this loop so we can deliver the SIGSEGV... 520 */ 521 if (handle_signal(signr, &ka, &info, oldset, scr)) { 522 /* 523 * A signal was successfully delivered; the saved 524 * sigmask will have been stored in the signal frame, 525 * and will be restored by sigreturn, so we can simply 526 * clear the TS_RESTORE_SIGMASK flag. 527 */ 528 current_thread_info()->status &= ~TS_RESTORE_SIGMASK; 529 return; 530 } 531 } 532 533 /* Did we come from a system call? */ 534 if (restart) { 535 /* Restart the system call - no handlers present */ 536 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR 537 || errno == ERESTART_RESTARTBLOCK) 538 { 539 /* 540 * Note: the syscall number is in r15 which is saved in 541 * pt_regs so all we need to do here is adjust ip so that 542 * the "break" instruction gets re-executed. 543 */ 544 ia64_decrement_ip(&scr->pt); 545 if (errno == ERESTART_RESTARTBLOCK) 546 scr->pt.r15 = __NR_restart_syscall; 547 } 548 } 549 550 /* if there's no signal to deliver, we just put the saved sigmask 551 * back */ 552 if (current_thread_info()->status & TS_RESTORE_SIGMASK) { 553 current_thread_info()->status &= ~TS_RESTORE_SIGMASK; 554 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 555 } 556 } 557