1 /* 2 * arch/s390/kernel/signal.c 3 * 4 * S390 version 5 * Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation 6 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) 7 * 8 * Based on Intel version 9 * 10 * Copyright (C) 1991, 1992 Linus Torvalds 11 * 12 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson 13 */ 14 15 #include <linux/config.h> 16 #include <linux/sched.h> 17 #include <linux/mm.h> 18 #include <linux/smp.h> 19 #include <linux/smp_lock.h> 20 #include <linux/kernel.h> 21 #include <linux/signal.h> 22 #include <linux/errno.h> 23 #include <linux/wait.h> 24 #include <linux/ptrace.h> 25 #include <linux/unistd.h> 26 #include <linux/stddef.h> 27 #include <linux/tty.h> 28 #include <linux/personality.h> 29 #include <linux/binfmts.h> 30 #include <asm/ucontext.h> 31 #include <asm/uaccess.h> 32 #include <asm/lowcore.h> 33 34 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 35 36 37 typedef struct 38 { 39 __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; 40 struct sigcontext sc; 41 _sigregs sregs; 42 int signo; 43 __u8 retcode[S390_SYSCALL_SIZE]; 44 } sigframe; 45 46 typedef struct 47 { 48 __u8 callee_used_stack[__SIGNAL_FRAMESIZE]; 49 __u8 retcode[S390_SYSCALL_SIZE]; 50 struct siginfo info; 51 struct ucontext uc; 52 } rt_sigframe; 53 54 int do_signal(struct pt_regs *regs, sigset_t *oldset); 55 56 /* 57 * Atomically swap in the new signal mask, and wait for a signal. 58 */ 59 asmlinkage int 60 sys_sigsuspend(struct pt_regs * regs, int history0, int history1, 61 old_sigset_t mask) 62 { 63 sigset_t saveset; 64 65 mask &= _BLOCKABLE; 66 spin_lock_irq(¤t->sighand->siglock); 67 saveset = current->blocked; 68 siginitset(¤t->blocked, mask); 69 recalc_sigpending(); 70 spin_unlock_irq(¤t->sighand->siglock); 71 regs->gprs[2] = -EINTR; 72 73 while (1) { 74 set_current_state(TASK_INTERRUPTIBLE); 75 schedule(); 76 if (do_signal(regs, &saveset)) 77 return -EINTR; 78 } 79 } 80 81 asmlinkage long 82 sys_rt_sigsuspend(struct pt_regs *regs, sigset_t __user *unewset, 83 size_t sigsetsize) 84 { 85 sigset_t saveset, newset; 86 87 /* XXX: Don't preclude handling different sized sigset_t's. */ 88 if (sigsetsize != sizeof(sigset_t)) 89 return -EINVAL; 90 91 if (copy_from_user(&newset, unewset, sizeof(newset))) 92 return -EFAULT; 93 sigdelsetmask(&newset, ~_BLOCKABLE); 94 95 spin_lock_irq(¤t->sighand->siglock); 96 saveset = current->blocked; 97 current->blocked = newset; 98 recalc_sigpending(); 99 spin_unlock_irq(¤t->sighand->siglock); 100 regs->gprs[2] = -EINTR; 101 102 while (1) { 103 set_current_state(TASK_INTERRUPTIBLE); 104 schedule(); 105 if (do_signal(regs, &saveset)) 106 return -EINTR; 107 } 108 } 109 110 asmlinkage long 111 sys_sigaction(int sig, const struct old_sigaction __user *act, 112 struct old_sigaction __user *oact) 113 { 114 struct k_sigaction new_ka, old_ka; 115 int ret; 116 117 if (act) { 118 old_sigset_t mask; 119 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 120 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 121 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) 122 return -EFAULT; 123 __get_user(new_ka.sa.sa_flags, &act->sa_flags); 124 __get_user(mask, &act->sa_mask); 125 siginitset(&new_ka.sa.sa_mask, mask); 126 } 127 128 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 129 130 if (!ret && oact) { 131 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 132 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 133 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) 134 return -EFAULT; 135 __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 136 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 137 } 138 139 return ret; 140 } 141 142 asmlinkage long 143 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 144 struct pt_regs *regs) 145 { 146 return do_sigaltstack(uss, uoss, regs->gprs[15]); 147 } 148 149 150 151 /* Returns non-zero on fault. */ 152 static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs) 153 { 154 unsigned long old_mask = regs->psw.mask; 155 int err; 156 157 save_access_regs(current->thread.acrs); 158 159 /* Copy a 'clean' PSW mask to the user to avoid leaking 160 information about whether PER is currently on. */ 161 regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask); 162 err = __copy_to_user(&sregs->regs.psw, ®s->psw, 163 sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs)); 164 regs->psw.mask = old_mask; 165 if (err != 0) 166 return err; 167 err = __copy_to_user(&sregs->regs.acrs, current->thread.acrs, 168 sizeof(sregs->regs.acrs)); 169 if (err != 0) 170 return err; 171 /* 172 * We have to store the fp registers to current->thread.fp_regs 173 * to merge them with the emulated registers. 174 */ 175 save_fp_regs(¤t->thread.fp_regs); 176 return __copy_to_user(&sregs->fpregs, ¤t->thread.fp_regs, 177 sizeof(s390_fp_regs)); 178 } 179 180 /* Returns positive number on error */ 181 static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs) 182 { 183 unsigned long old_mask = regs->psw.mask; 184 int err; 185 186 /* Alwys make any pending restarted system call return -EINTR */ 187 current_thread_info()->restart_block.fn = do_no_restart_syscall; 188 189 err = __copy_from_user(®s->psw, &sregs->regs.psw, 190 sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs)); 191 regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask); 192 regs->psw.addr |= PSW_ADDR_AMODE; 193 if (err) 194 return err; 195 err = __copy_from_user(¤t->thread.acrs, &sregs->regs.acrs, 196 sizeof(sregs->regs.acrs)); 197 if (err) 198 return err; 199 restore_access_regs(current->thread.acrs); 200 201 err = __copy_from_user(¤t->thread.fp_regs, &sregs->fpregs, 202 sizeof(s390_fp_regs)); 203 current->thread.fp_regs.fpc &= FPC_VALID_MASK; 204 if (err) 205 return err; 206 207 restore_fp_regs(¤t->thread.fp_regs); 208 regs->trap = -1; /* disable syscall checks */ 209 return 0; 210 } 211 212 asmlinkage long sys_sigreturn(struct pt_regs *regs) 213 { 214 sigframe __user *frame = (sigframe __user *)regs->gprs[15]; 215 sigset_t set; 216 217 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 218 goto badframe; 219 if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE)) 220 goto badframe; 221 222 sigdelsetmask(&set, ~_BLOCKABLE); 223 spin_lock_irq(¤t->sighand->siglock); 224 current->blocked = set; 225 recalc_sigpending(); 226 spin_unlock_irq(¤t->sighand->siglock); 227 228 if (restore_sigregs(regs, &frame->sregs)) 229 goto badframe; 230 231 return regs->gprs[2]; 232 233 badframe: 234 force_sig(SIGSEGV, current); 235 return 0; 236 } 237 238 asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) 239 { 240 rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15]; 241 sigset_t set; 242 243 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 244 goto badframe; 245 if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set))) 246 goto badframe; 247 248 sigdelsetmask(&set, ~_BLOCKABLE); 249 spin_lock_irq(¤t->sighand->siglock); 250 current->blocked = set; 251 recalc_sigpending(); 252 spin_unlock_irq(¤t->sighand->siglock); 253 254 if (restore_sigregs(regs, &frame->uc.uc_mcontext)) 255 goto badframe; 256 257 if (do_sigaltstack(&frame->uc.uc_stack, NULL, 258 regs->gprs[15]) == -EFAULT) 259 goto badframe; 260 return regs->gprs[2]; 261 262 badframe: 263 force_sig(SIGSEGV, current); 264 return 0; 265 } 266 267 /* 268 * Set up a signal frame. 269 */ 270 271 272 /* 273 * Determine which stack to use.. 274 */ 275 static inline void __user * 276 get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) 277 { 278 unsigned long sp; 279 280 /* Default to using normal stack */ 281 sp = regs->gprs[15]; 282 283 /* This is the X/Open sanctioned signal stack switching. */ 284 if (ka->sa.sa_flags & SA_ONSTACK) { 285 if (! sas_ss_flags(sp)) 286 sp = current->sas_ss_sp + current->sas_ss_size; 287 } 288 289 /* This is the legacy signal stack switching. */ 290 else if (!user_mode(regs) && 291 !(ka->sa.sa_flags & SA_RESTORER) && 292 ka->sa.sa_restorer) { 293 sp = (unsigned long) ka->sa.sa_restorer; 294 } 295 296 return (void __user *)((sp - frame_size) & -8ul); 297 } 298 299 static inline int map_signal(int sig) 300 { 301 if (current_thread_info()->exec_domain 302 && current_thread_info()->exec_domain->signal_invmap 303 && sig < 32) 304 return current_thread_info()->exec_domain->signal_invmap[sig]; 305 else 306 return sig; 307 } 308 309 static void setup_frame(int sig, struct k_sigaction *ka, 310 sigset_t *set, struct pt_regs * regs) 311 { 312 sigframe __user *frame; 313 314 frame = get_sigframe(ka, regs, sizeof(sigframe)); 315 if (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe))) 316 goto give_sigsegv; 317 318 if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE)) 319 goto give_sigsegv; 320 321 if (save_sigregs(regs, &frame->sregs)) 322 goto give_sigsegv; 323 if (__put_user(&frame->sregs, &frame->sc.sregs)) 324 goto give_sigsegv; 325 326 /* Set up to return from userspace. If provided, use a stub 327 already in userspace. */ 328 if (ka->sa.sa_flags & SA_RESTORER) { 329 regs->gprs[14] = (unsigned long) 330 ka->sa.sa_restorer | PSW_ADDR_AMODE; 331 } else { 332 regs->gprs[14] = (unsigned long) 333 frame->retcode | PSW_ADDR_AMODE; 334 if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn, 335 (u16 __user *)(frame->retcode))) 336 goto give_sigsegv; 337 } 338 339 /* Set up backchain. */ 340 if (__put_user(regs->gprs[15], (addr_t __user *) frame)) 341 goto give_sigsegv; 342 343 /* Set up registers for signal handler */ 344 regs->gprs[15] = (unsigned long) frame; 345 regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE; 346 347 regs->gprs[2] = map_signal(sig); 348 regs->gprs[3] = (unsigned long) &frame->sc; 349 350 /* We forgot to include these in the sigcontext. 351 To avoid breaking binary compatibility, they are passed as args. */ 352 regs->gprs[4] = current->thread.trap_no; 353 regs->gprs[5] = current->thread.prot_addr; 354 355 /* Place signal number on stack to allow backtrace from handler. */ 356 if (__put_user(regs->gprs[2], (int __user *) &frame->signo)) 357 goto give_sigsegv; 358 return; 359 360 give_sigsegv: 361 force_sigsegv(sig, current); 362 } 363 364 static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 365 sigset_t *set, struct pt_regs * regs) 366 { 367 int err = 0; 368 rt_sigframe __user *frame; 369 370 frame = get_sigframe(ka, regs, sizeof(rt_sigframe)); 371 if (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe))) 372 goto give_sigsegv; 373 374 if (copy_siginfo_to_user(&frame->info, info)) 375 goto give_sigsegv; 376 377 /* Create the ucontext. */ 378 err |= __put_user(0, &frame->uc.uc_flags); 379 err |= __put_user(NULL, &frame->uc.uc_link); 380 err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); 381 err |= __put_user(sas_ss_flags(regs->gprs[15]), 382 &frame->uc.uc_stack.ss_flags); 383 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); 384 err |= save_sigregs(regs, &frame->uc.uc_mcontext); 385 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 386 if (err) 387 goto give_sigsegv; 388 389 /* Set up to return from userspace. If provided, use a stub 390 already in userspace. */ 391 if (ka->sa.sa_flags & SA_RESTORER) { 392 regs->gprs[14] = (unsigned long) 393 ka->sa.sa_restorer | PSW_ADDR_AMODE; 394 } else { 395 regs->gprs[14] = (unsigned long) 396 frame->retcode | PSW_ADDR_AMODE; 397 err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn, 398 (u16 __user *)(frame->retcode)); 399 } 400 401 /* Set up backchain. */ 402 if (__put_user(regs->gprs[15], (addr_t __user *) frame)) 403 goto give_sigsegv; 404 405 /* Set up registers for signal handler */ 406 regs->gprs[15] = (unsigned long) frame; 407 regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE; 408 409 regs->gprs[2] = map_signal(sig); 410 regs->gprs[3] = (unsigned long) &frame->info; 411 regs->gprs[4] = (unsigned long) &frame->uc; 412 return; 413 414 give_sigsegv: 415 force_sigsegv(sig, current); 416 } 417 418 /* 419 * OK, we're invoking a handler 420 */ 421 422 static void 423 handle_signal(unsigned long sig, struct k_sigaction *ka, 424 siginfo_t *info, sigset_t *oldset, struct pt_regs * regs) 425 { 426 /* Set up the stack frame */ 427 if (ka->sa.sa_flags & SA_SIGINFO) 428 setup_rt_frame(sig, ka, info, oldset, regs); 429 else 430 setup_frame(sig, ka, oldset, regs); 431 432 spin_lock_irq(¤t->sighand->siglock); 433 sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); 434 if (!(ka->sa.sa_flags & SA_NODEFER)) 435 sigaddset(¤t->blocked,sig); 436 recalc_sigpending(); 437 spin_unlock_irq(¤t->sighand->siglock); 438 } 439 440 /* 441 * Note that 'init' is a special process: it doesn't get signals it doesn't 442 * want to handle. Thus you cannot kill init even with a SIGKILL even by 443 * mistake. 444 * 445 * Note that we go through the signals twice: once to check the signals that 446 * the kernel can handle, and then we build all the user-level signal handling 447 * stack-frames in one go after that. 448 */ 449 int do_signal(struct pt_regs *regs, sigset_t *oldset) 450 { 451 unsigned long retval = 0, continue_addr = 0, restart_addr = 0; 452 siginfo_t info; 453 int signr; 454 struct k_sigaction ka; 455 456 /* 457 * We want the common case to go fast, which 458 * is why we may in certain cases get here from 459 * kernel mode. Just return without doing anything 460 * if so. 461 */ 462 if (!user_mode(regs)) 463 return 1; 464 465 if (!oldset) 466 oldset = ¤t->blocked; 467 468 /* Are we from a system call? */ 469 if (regs->trap == __LC_SVC_OLD_PSW) { 470 continue_addr = regs->psw.addr; 471 restart_addr = continue_addr - regs->ilc; 472 retval = regs->gprs[2]; 473 474 /* Prepare for system call restart. We do this here so that a 475 debugger will see the already changed PSW. */ 476 if (retval == -ERESTARTNOHAND || 477 retval == -ERESTARTSYS || 478 retval == -ERESTARTNOINTR) { 479 regs->gprs[2] = regs->orig_gpr2; 480 regs->psw.addr = restart_addr; 481 } else if (retval == -ERESTART_RESTARTBLOCK) { 482 regs->gprs[2] = -EINTR; 483 } 484 } 485 486 /* Get signal to deliver. When running under ptrace, at this point 487 the debugger may change all our registers ... */ 488 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 489 490 /* Depending on the signal settings we may need to revert the 491 decision to restart the system call. */ 492 if (signr > 0 && regs->psw.addr == restart_addr) { 493 if (retval == -ERESTARTNOHAND 494 || (retval == -ERESTARTSYS 495 && !(current->sighand->action[signr-1].sa.sa_flags 496 & SA_RESTART))) { 497 regs->gprs[2] = -EINTR; 498 regs->psw.addr = continue_addr; 499 } 500 } 501 502 if (signr > 0) { 503 /* Whee! Actually deliver the signal. */ 504 #ifdef CONFIG_COMPAT 505 if (test_thread_flag(TIF_31BIT)) { 506 extern void handle_signal32(unsigned long sig, 507 struct k_sigaction *ka, 508 siginfo_t *info, 509 sigset_t *oldset, 510 struct pt_regs *regs); 511 handle_signal32(signr, &ka, &info, oldset, regs); 512 return 1; 513 } 514 #endif 515 handle_signal(signr, &ka, &info, oldset, regs); 516 return 1; 517 } 518 519 /* Restart a different system call. */ 520 if (retval == -ERESTART_RESTARTBLOCK 521 && regs->psw.addr == continue_addr) { 522 regs->gprs[2] = __NR_restart_syscall; 523 set_thread_flag(TIF_RESTART_SVC); 524 } 525 return 0; 526 } 527