signal.c revision 2ba3e3e65cf182436757ba13ea8d564e2950fb56
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/config.h> 11#include <linux/errno.h> 12#include <linux/kernel.h> 13#include <linux/mm.h> 14#include <linux/ptrace.h> 15#include <linux/sched.h> 16#include <linux/signal.h> 17#include <linux/smp.h> 18#include <linux/smp_lock.h> 19#include <linux/stddef.h> 20#include <linux/tty.h> 21#include <linux/binfmts.h> 22#include <linux/unistd.h> 23#include <linux/wait.h> 24 25#include <asm/ia32.h> 26#include <asm/intrinsics.h> 27#include <asm/uaccess.h> 28#include <asm/rse.h> 29#include <asm/sigcontext.h> 30 31#include "sigframe.h" 32 33#define DEBUG_SIG 0 34#define STACK_ALIGN 16 /* minimal alignment for stack pointer */ 35#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 36 37#if _NSIG_WORDS > 1 38# define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t)) 39# define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t)) 40#else 41# define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0]) 42# define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0]) 43#endif 44 45long 46ia64_rt_sigsuspend (sigset_t __user *uset, size_t sigsetsize, struct sigscratch *scr) 47{ 48 sigset_t oldset, set; 49 50 /* XXX: Don't preclude handling different sized sigset_t's. */ 51 if (sigsetsize != sizeof(sigset_t)) 52 return -EINVAL; 53 54 if (!access_ok(VERIFY_READ, uset, sigsetsize)) 55 return -EFAULT; 56 57 if (GET_SIGSET(&set, uset)) 58 return -EFAULT; 59 60 sigdelsetmask(&set, ~_BLOCKABLE); 61 62 spin_lock_irq(¤t->sighand->siglock); 63 { 64 oldset = current->blocked; 65 current->blocked = set; 66 recalc_sigpending(); 67 } 68 spin_unlock_irq(¤t->sighand->siglock); 69 70 /* 71 * The return below usually returns to the signal handler. We need to 72 * pre-set the correct error code here to ensure that the right values 73 * get saved in sigcontext by ia64_do_signal. 74 */ 75 scr->pt.r8 = EINTR; 76 scr->pt.r10 = -1; 77 78 while (1) { 79 current->state = TASK_INTERRUPTIBLE; 80 schedule(); 81 if (ia64_do_signal(&oldset, scr, 1)) 82 return -EINTR; 83 } 84} 85 86asmlinkage long 87sys_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, long arg2, 88 long arg3, long arg4, long arg5, long arg6, long arg7, 89 struct pt_regs regs) 90{ 91 return do_sigaltstack(uss, uoss, regs.r12); 92} 93 94static long 95restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr) 96{ 97 unsigned long ip, flags, nat, um, cfm, rsc; 98 long err; 99 100 /* Always make any pending restarted system calls return -EINTR */ 101 current_thread_info()->restart_block.fn = do_no_restart_syscall; 102 103 /* restore scratch that always needs gets updated during signal delivery: */ 104 err = __get_user(flags, &sc->sc_flags); 105 err |= __get_user(nat, &sc->sc_nat); 106 err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */ 107 err |= __get_user(cfm, &sc->sc_cfm); 108 err |= __get_user(um, &sc->sc_um); /* user mask */ 109 err |= __get_user(rsc, &sc->sc_ar_rsc); 110 err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat); 111 err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); 112 err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs); 113 err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */ 114 err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */ 115 err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */ 116 err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8); /* r1 */ 117 err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */ 118 err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8); /* r12-r13 */ 119 err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8); /* r15 */ 120 121 scr->pt.cr_ifs = cfm | (1UL << 63); 122 scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */ 123 124 /* establish new instruction pointer: */ 125 scr->pt.cr_iip = ip & ~0x3UL; 126 ia64_psr(&scr->pt)->ri = ip & 0x3; 127 scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM); 128 129 scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat); 130 131 if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) { 132 /* Restore most scratch-state only when not in syscall. */ 133 err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */ 134 err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */ 135 err |= __get_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */ 136 err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */ 137 err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8); /* r2-r3 */ 138 err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */ 139 } 140 141 if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) { 142 struct ia64_psr *psr = ia64_psr(&scr->pt); 143 144 __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16); 145 psr->mfh = 0; /* drop signal handler's fph contents... */ 146 preempt_disable(); 147 if (psr->dfh) 148 ia64_drop_fpu(current); 149 else { 150 /* We already own the local fph, otherwise psr->dfh wouldn't be 0. */ 151 __ia64_load_fpu(current->thread.fph); 152 ia64_set_local_fpu_owner(current); 153 } 154 preempt_enable(); 155 } 156 return err; 157} 158 159int 160copy_siginfo_to_user (siginfo_t __user *to, siginfo_t *from) 161{ 162 if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t))) 163 return -EFAULT; 164 if (from->si_code < 0) { 165 if (__copy_to_user(to, from, sizeof(siginfo_t))) 166 return -EFAULT; 167 return 0; 168 } else { 169 int err; 170 171 /* 172 * If you change siginfo_t structure, please be sure this code is fixed 173 * accordingly. It should never copy any pad contained in the structure 174 * to avoid security leaks, but must copy the generic 3 ints plus the 175 * relevant union member. 176 */ 177 err = __put_user(from->si_signo, &to->si_signo); 178 err |= __put_user(from->si_errno, &to->si_errno); 179 err |= __put_user((short)from->si_code, &to->si_code); 180 switch (from->si_code >> 16) { 181 case __SI_FAULT >> 16: 182 err |= __put_user(from->si_flags, &to->si_flags); 183 err |= __put_user(from->si_isr, &to->si_isr); 184 case __SI_POLL >> 16: 185 err |= __put_user(from->si_addr, &to->si_addr); 186 err |= __put_user(from->si_imm, &to->si_imm); 187 break; 188 case __SI_TIMER >> 16: 189 err |= __put_user(from->si_tid, &to->si_tid); 190 err |= __put_user(from->si_overrun, &to->si_overrun); 191 err |= __put_user(from->si_ptr, &to->si_ptr); 192 break; 193 case __SI_RT >> 16: /* Not generated by the kernel as of now. */ 194 case __SI_MESGQ >> 16: 195 err |= __put_user(from->si_uid, &to->si_uid); 196 err |= __put_user(from->si_pid, &to->si_pid); 197 err |= __put_user(from->si_ptr, &to->si_ptr); 198 break; 199 case __SI_CHLD >> 16: 200 err |= __put_user(from->si_utime, &to->si_utime); 201 err |= __put_user(from->si_stime, &to->si_stime); 202 err |= __put_user(from->si_status, &to->si_status); 203 default: 204 err |= __put_user(from->si_uid, &to->si_uid); 205 err |= __put_user(from->si_pid, &to->si_pid); 206 break; 207 } 208 return err; 209 } 210} 211 212long 213ia64_rt_sigreturn (struct sigscratch *scr) 214{ 215 extern char ia64_strace_leave_kernel, ia64_leave_kernel; 216 struct sigcontext __user *sc; 217 struct siginfo si; 218 sigset_t set; 219 long retval; 220 221 sc = &((struct sigframe __user *) (scr->pt.r12 + 16))->sc; 222 223 /* 224 * When we return to the previously executing context, r8 and r10 have already 225 * been setup the way we want them. Indeed, if the signal wasn't delivered while 226 * in a system call, we must not touch r8 or r10 as otherwise user-level state 227 * could be corrupted. 228 */ 229 retval = (long) &ia64_leave_kernel; 230 if (test_thread_flag(TIF_SYSCALL_TRACE) 231 || test_thread_flag(TIF_SYSCALL_AUDIT)) 232 /* 233 * strace expects to be notified after sigreturn returns even though the 234 * context to which we return may not be in the middle of a syscall. 235 * Thus, the return-value that strace displays for sigreturn is 236 * meaningless. 237 */ 238 retval = (long) &ia64_strace_leave_kernel; 239 240 if (!access_ok(VERIFY_READ, sc, sizeof(*sc))) 241 goto give_sigsegv; 242 243 if (GET_SIGSET(&set, &sc->sc_mask)) 244 goto give_sigsegv; 245 246 sigdelsetmask(&set, ~_BLOCKABLE); 247 248 spin_lock_irq(¤t->sighand->siglock); 249 { 250 current->blocked = set; 251 recalc_sigpending(); 252 } 253 spin_unlock_irq(¤t->sighand->siglock); 254 255 if (restore_sigcontext(sc, scr)) 256 goto give_sigsegv; 257 258#if DEBUG_SIG 259 printk("SIG return (%s:%d): sp=%lx ip=%lx\n", 260 current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip); 261#endif 262 /* 263 * It is more difficult to avoid calling this function than to 264 * call it and ignore errors. 265 */ 266 do_sigaltstack(&sc->sc_stack, NULL, scr->pt.r12); 267 return retval; 268 269 give_sigsegv: 270 si.si_signo = SIGSEGV; 271 si.si_errno = 0; 272 si.si_code = SI_KERNEL; 273 si.si_pid = current->pid; 274 si.si_uid = current->uid; 275 si.si_addr = sc; 276 force_sig_info(SIGSEGV, &si, current); 277 return retval; 278} 279 280/* 281 * This does just the minimum required setup of sigcontext. 282 * Specifically, it only installs data that is either not knowable at 283 * the user-level or that gets modified before execution in the 284 * trampoline starts. Everything else is done at the user-level. 285 */ 286static long 287setup_sigcontext (struct sigcontext __user *sc, sigset_t *mask, struct sigscratch *scr) 288{ 289 unsigned long flags = 0, ifs, cfm, nat; 290 long err; 291 292 ifs = scr->pt.cr_ifs; 293 294 if (on_sig_stack((unsigned long) sc)) 295 flags |= IA64_SC_FLAG_ONSTACK; 296 if ((ifs & (1UL << 63)) == 0) 297 /* if cr_ifs doesn't have the valid bit set, we got here through a syscall */ 298 flags |= IA64_SC_FLAG_IN_SYSCALL; 299 cfm = ifs & ((1UL << 38) - 1); 300 ia64_flush_fph(current); 301 if ((current->thread.flags & IA64_THREAD_FPH_VALID)) { 302 flags |= IA64_SC_FLAG_FPH_VALID; 303 __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16); 304 } 305 306 nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat); 307 308 err = __put_user(flags, &sc->sc_flags); 309 err |= __put_user(nat, &sc->sc_nat); 310 err |= PUT_SIGSET(mask, &sc->sc_mask); 311 err |= __put_user(cfm, &sc->sc_cfm); 312 err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um); 313 err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc); 314 err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */ 315 err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */ 316 err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs); 317 err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */ 318 err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */ 319 err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */ 320 err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 8); /* r1 */ 321 err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */ 322 err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 2*8); /* r12-r13 */ 323 err |= __copy_to_user(&sc->sc_gr[15], &scr->pt.r15, 8); /* r15 */ 324 err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip); 325 326 if (flags & IA64_SC_FLAG_IN_SYSCALL) { 327 /* Clear scratch registers if the signal interrupted a system call. */ 328 err |= __put_user(0, &sc->sc_ar_ccv); /* ar.ccv */ 329 err |= __put_user(0, &sc->sc_br[7]); /* b7 */ 330 err |= __put_user(0, &sc->sc_gr[14]); /* r14 */ 331 err |= __clear_user(&sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */ 332 err |= __clear_user(&sc->sc_gr[2], 2*8); /* r2-r3 */ 333 err |= __clear_user(&sc->sc_gr[16], 16*8); /* r16-r31 */ 334 } else { 335 /* Copy scratch regs to sigcontext if the signal didn't interrupt a syscall. */ 336 err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv); /* ar.ccv */ 337 err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */ 338 err |= __put_user(scr->pt.r14, &sc->sc_gr[14]); /* r14 */ 339 err |= __copy_to_user(&sc->sc_ar25, &scr->pt.ar_csd, 2*8); /* ar.csd & ar.ssd */ 340 err |= __copy_to_user(&sc->sc_gr[2], &scr->pt.r2, 2*8); /* r2-r3 */ 341 err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */ 342 } 343 return err; 344} 345 346/* 347 * Check whether the register-backing store is already on the signal stack. 348 */ 349static inline int 350rbs_on_sig_stack (unsigned long bsp) 351{ 352 return (bsp - current->sas_ss_sp < current->sas_ss_size); 353} 354 355static long 356force_sigsegv_info (int sig, void __user *addr) 357{ 358 unsigned long flags; 359 struct siginfo si; 360 361 if (sig == SIGSEGV) { 362 /* 363 * Acquiring siglock around the sa_handler-update is almost 364 * certainly overkill, but this isn't a 365 * performance-critical path and I'd rather play it safe 366 * here than having to debug a nasty race if and when 367 * something changes in kernel/signal.c that would make it 368 * no longer safe to modify sa_handler without holding the 369 * lock. 370 */ 371 spin_lock_irqsave(¤t->sighand->siglock, flags); 372 current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; 373 spin_unlock_irqrestore(¤t->sighand->siglock, flags); 374 } 375 si.si_signo = SIGSEGV; 376 si.si_errno = 0; 377 si.si_code = SI_KERNEL; 378 si.si_pid = current->pid; 379 si.si_uid = current->uid; 380 si.si_addr = addr; 381 force_sig_info(SIGSEGV, &si, current); 382 return 0; 383} 384 385static long 386setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, 387 struct sigscratch *scr) 388{ 389 extern char __kernel_sigtramp[]; 390 unsigned long tramp_addr, new_rbs = 0; 391 struct sigframe __user *frame; 392 long err; 393 394 frame = (void __user *) scr->pt.r12; 395 tramp_addr = (unsigned long) __kernel_sigtramp; 396 if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags((unsigned long) frame) == 0) { 397 frame = (void __user *) ((current->sas_ss_sp + current->sas_ss_size) 398 & ~(STACK_ALIGN - 1)); 399 /* 400 * We need to check for the register stack being on the signal stack 401 * separately, because it's switched separately (memory stack is switched 402 * in the kernel, register stack is switched in the signal trampoline). 403 */ 404 if (!rbs_on_sig_stack(scr->pt.ar_bspstore)) 405 new_rbs = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1); 406 } 407 frame = (void __user *) frame - ((sizeof(*frame) + STACK_ALIGN - 1) & ~(STACK_ALIGN - 1)); 408 409 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 410 return force_sigsegv_info(sig, frame); 411 412 err = __put_user(sig, &frame->arg0); 413 err |= __put_user(&frame->info, &frame->arg1); 414 err |= __put_user(&frame->sc, &frame->arg2); 415 err |= __put_user(new_rbs, &frame->sc.sc_rbs_base); 416 err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */ 417 err |= __put_user(ka->sa.sa_handler, &frame->handler); 418 419 err |= copy_siginfo_to_user(&frame->info, info); 420 421 err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp); 422 err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size); 423 err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags); 424 err |= setup_sigcontext(&frame->sc, set, scr); 425 426 if (unlikely(err)) 427 return force_sigsegv_info(sig, frame); 428 429 scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */ 430 scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */ 431 scr->pt.cr_iip = tramp_addr; 432 ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */ 433 ia64_psr(&scr->pt)->be = 0; /* force little-endian byte-order */ 434 /* 435 * Force the interruption function mask to zero. This has no effect when a 436 * system-call got interrupted by a signal (since, in that case, scr->pt_cr_ifs is 437 * ignored), but it has the desirable effect of making it possible to deliver a 438 * signal with an incomplete register frame (which happens when a mandatory RSE 439 * load faults). Furthermore, it has no negative effect on the getting the user's 440 * dirty partition preserved, because that's governed by scr->pt.loadrs. 441 */ 442 scr->pt.cr_ifs = (1UL << 63); 443 444 /* 445 * Note: this affects only the NaT bits of the scratch regs (the ones saved in 446 * pt_regs), which is exactly what we want. 447 */ 448 scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */ 449 450#if DEBUG_SIG 451 printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%p\n", 452 current->comm, current->pid, sig, scr->pt.r12, frame->sc.sc_ip, frame->handler); 453#endif 454 return 1; 455} 456 457static long 458handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, 459 struct sigscratch *scr) 460{ 461 if (IS_IA32_PROCESS(&scr->pt)) { 462 /* send signal to IA-32 process */ 463 if (!ia32_setup_frame1(sig, ka, info, oldset, &scr->pt)) 464 return 0; 465 } else 466 /* send signal to IA-64 process */ 467 if (!setup_frame(sig, ka, info, oldset, scr)) 468 return 0; 469 470 if (!(ka->sa.sa_flags & SA_NODEFER)) { 471 spin_lock_irq(¤t->sighand->siglock); 472 { 473 sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); 474 sigaddset(¤t->blocked, sig); 475 recalc_sigpending(); 476 } 477 spin_unlock_irq(¤t->sighand->siglock); 478 } 479 return 1; 480} 481 482/* 483 * Note that `init' is a special process: it doesn't get signals it doesn't want to 484 * handle. Thus you cannot kill init even with a SIGKILL even by mistake. 485 */ 486long 487ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall) 488{ 489 struct k_sigaction ka; 490 siginfo_t info; 491 long restart = in_syscall; 492 long errno = scr->pt.r8; 493# define ERR_CODE(c) (IS_IA32_PROCESS(&scr->pt) ? -(c) : (c)) 494 495 /* 496 * In the ia64_leave_kernel code path, we want the common case to go fast, which 497 * is why we may in certain cases get here from kernel mode. Just return without 498 * doing anything if so. 499 */ 500 if (!user_mode(&scr->pt)) 501 return 0; 502 503 if (!oldset) 504 oldset = ¤t->blocked; 505 506 /* 507 * This only loops in the rare cases of handle_signal() failing, in which case we 508 * need to push through a forced SIGSEGV. 509 */ 510 while (1) { 511 int signr = get_signal_to_deliver(&info, &ka, &scr->pt, NULL); 512 513 /* 514 * get_signal_to_deliver() may have run a debugger (via notify_parent()) 515 * and the debugger may have modified the state (e.g., to arrange for an 516 * inferior call), thus it's important to check for restarting _after_ 517 * get_signal_to_deliver(). 518 */ 519 if (IS_IA32_PROCESS(&scr->pt)) { 520 if (in_syscall) { 521 if (errno >= 0) 522 restart = 0; 523 else 524 errno = -errno; 525 } 526 } else if ((long) scr->pt.r10 != -1) 527 /* 528 * A system calls has to be restarted only if one of the error codes 529 * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10 530 * isn't -1 then r8 doesn't hold an error code and we don't need to 531 * restart the syscall, so we can clear the "restart" flag here. 532 */ 533 restart = 0; 534 535 if (signr <= 0) 536 break; 537 538 if (unlikely(restart)) { 539 switch (errno) { 540 case ERESTART_RESTARTBLOCK: 541 case ERESTARTNOHAND: 542 scr->pt.r8 = ERR_CODE(EINTR); 543 /* note: scr->pt.r10 is already -1 */ 544 break; 545 546 case ERESTARTSYS: 547 if ((ka.sa.sa_flags & SA_RESTART) == 0) { 548 scr->pt.r8 = ERR_CODE(EINTR); 549 /* note: scr->pt.r10 is already -1 */ 550 break; 551 } 552 case ERESTARTNOINTR: 553 if (IS_IA32_PROCESS(&scr->pt)) { 554 scr->pt.r8 = scr->pt.r1; 555 scr->pt.cr_iip -= 2; 556 } else 557 ia64_decrement_ip(&scr->pt); 558 restart = 0; /* don't restart twice if handle_signal() fails... */ 559 } 560 } 561 562 /* 563 * Whee! Actually deliver the signal. If the delivery failed, we need to 564 * continue to iterate in this loop so we can deliver the SIGSEGV... 565 */ 566 if (handle_signal(signr, &ka, &info, oldset, scr)) 567 return 1; 568 } 569 570 /* Did we come from a system call? */ 571 if (restart) { 572 /* Restart the system call - no handlers present */ 573 if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR 574 || errno == ERESTART_RESTARTBLOCK) 575 { 576 if (IS_IA32_PROCESS(&scr->pt)) { 577 scr->pt.r8 = scr->pt.r1; 578 scr->pt.cr_iip -= 2; 579 if (errno == ERESTART_RESTARTBLOCK) 580 scr->pt.r8 = 0; /* x86 version of __NR_restart_syscall */ 581 } else { 582 /* 583 * Note: the syscall number is in r15 which is saved in 584 * pt_regs so all we need to do here is adjust ip so that 585 * the "break" instruction gets re-executed. 586 */ 587 ia64_decrement_ip(&scr->pt); 588 if (errno == ERESTART_RESTARTBLOCK) 589 scr->pt.r15 = __NR_restart_syscall; 590 } 591 } 592 } 593 return 0; 594} 595 596/* Set a delayed signal that was detected in MCA/INIT/NMI/PMI context where it 597 * could not be delivered. It is important that the target process is not 598 * allowed to do any more work in user space. Possible cases for the target 599 * process: 600 * 601 * - It is sleeping and will wake up soon. Store the data in the current task, 602 * the signal will be sent when the current task returns from the next 603 * interrupt. 604 * 605 * - It is running in user context. Store the data in the current task, the 606 * signal will be sent when the current task returns from the next interrupt. 607 * 608 * - It is running in kernel context on this or another cpu and will return to 609 * user context. Store the data in the target task, the signal will be sent 610 * to itself when the target task returns to user space. 611 * 612 * - It is running in kernel context on this cpu and will sleep before 613 * returning to user context. Because this is also the current task, the 614 * signal will not get delivered and the task could sleep indefinitely. 615 * Store the data in the idle task for this cpu, the signal will be sent 616 * after the idle task processes its next interrupt. 617 * 618 * To cover all cases, store the data in the target task, the current task and 619 * the idle task on this cpu. Whatever happens, the signal will be delivered 620 * to the target task before it can do any useful user space work. Multiple 621 * deliveries have no unwanted side effects. 622 * 623 * Note: This code is executed in MCA/INIT/NMI/PMI context, with interrupts 624 * disabled. It must not take any locks nor use kernel structures or services 625 * that require locks. 626 */ 627 628/* To ensure that we get the right pid, check its start time. To avoid extra 629 * include files in thread_info.h, convert the task start_time to unsigned long, 630 * giving us a cycle time of > 580 years. 631 */ 632static inline unsigned long 633start_time_ul(const struct task_struct *t) 634{ 635 return t->start_time.tv_sec * NSEC_PER_SEC + t->start_time.tv_nsec; 636} 637 638void 639set_sigdelayed(pid_t pid, int signo, int code, void __user *addr) 640{ 641 struct task_struct *t; 642 unsigned long start_time = 0; 643 int i; 644 645 for (i = 1; i <= 3; ++i) { 646 switch (i) { 647 case 1: 648 t = find_task_by_pid(pid); 649 if (t) 650 start_time = start_time_ul(t); 651 break; 652 case 2: 653 t = current; 654 break; 655 default: 656 t = idle_task(smp_processor_id()); 657 break; 658 } 659 660 if (!t) 661 return; 662 t->thread_info->sigdelayed.signo = signo; 663 t->thread_info->sigdelayed.code = code; 664 t->thread_info->sigdelayed.addr = addr; 665 t->thread_info->sigdelayed.start_time = start_time; 666 t->thread_info->sigdelayed.pid = pid; 667 wmb(); 668 set_tsk_thread_flag(t, TIF_SIGDELAYED); 669 } 670} 671 672/* Called from entry.S when it detects TIF_SIGDELAYED, a delayed signal that 673 * was detected in MCA/INIT/NMI/PMI context where it could not be delivered. 674 */ 675 676void 677do_sigdelayed(void) 678{ 679 struct siginfo siginfo; 680 pid_t pid; 681 struct task_struct *t; 682 683 clear_thread_flag(TIF_SIGDELAYED); 684 memset(&siginfo, 0, sizeof(siginfo)); 685 siginfo.si_signo = current_thread_info()->sigdelayed.signo; 686 siginfo.si_code = current_thread_info()->sigdelayed.code; 687 siginfo.si_addr = current_thread_info()->sigdelayed.addr; 688 pid = current_thread_info()->sigdelayed.pid; 689 t = find_task_by_pid(pid); 690 if (!t) 691 return; 692 if (current_thread_info()->sigdelayed.start_time != start_time_ul(t)) 693 return; 694 force_sig_info(siginfo.si_signo, &siginfo, t); 695} 696