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/io.h> 26 #include <linux/tracehook.h> 27 #include <asm/ucontext.h> 28 #include <asm/uaccess.h> 29 #include <asm/pgtable.h> 30 #include <asm/cacheflush.h> 31 #include <asm/syscalls.h> 32 #include <asm/fpu.h> 33 34 struct fdpic_func_descriptor { 35 unsigned long text; 36 unsigned long GOT; 37 }; 38 39 /* 40 * The following define adds a 64 byte gap between the signal 41 * stack frame and previous contents of the stack. This allows 42 * frame unwinding in a function epilogue but only if a frame 43 * pointer is used in the function. This is necessary because 44 * current gcc compilers (<4.3) do not generate unwind info on 45 * SH for function epilogues. 46 */ 47 #define UNWINDGUARD 64 48 49 /* 50 * Atomically swap in the new signal mask, and wait for a signal. 51 */ 52 asmlinkage int 53 sys_sigsuspend(old_sigset_t mask) 54 { 55 sigset_t blocked; 56 siginitset(&blocked, mask); 57 return sigsuspend(&blocked); 58 } 59 60 asmlinkage int 61 sys_sigaction(int sig, const struct old_sigaction __user *act, 62 struct old_sigaction __user *oact) 63 { 64 struct k_sigaction new_ka, old_ka; 65 int ret; 66 67 if (act) { 68 old_sigset_t mask; 69 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 70 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 71 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) || 72 __get_user(new_ka.sa.sa_flags, &act->sa_flags) || 73 __get_user(mask, &act->sa_mask)) 74 return -EFAULT; 75 siginitset(&new_ka.sa.sa_mask, mask); 76 } 77 78 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 79 80 if (!ret && oact) { 81 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 82 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 83 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) || 84 __put_user(old_ka.sa.sa_flags, &oact->sa_flags) || 85 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask)) 86 return -EFAULT; 87 } 88 89 return ret; 90 } 91 92 asmlinkage int 93 sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, 94 unsigned long r6, unsigned long r7, 95 struct pt_regs __regs) 96 { 97 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 98 99 return do_sigaltstack(uss, uoss, regs->regs[15]); 100 } 101 102 103 /* 104 * Do a signal return; undo the signal stack. 105 */ 106 107 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ 108 #if defined(CONFIG_CPU_SH2) 109 #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */ 110 #else 111 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */ 112 #endif 113 #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */ 114 115 struct sigframe 116 { 117 struct sigcontext sc; 118 unsigned long extramask[_NSIG_WORDS-1]; 119 u16 retcode[8]; 120 }; 121 122 struct rt_sigframe 123 { 124 struct siginfo info; 125 struct ucontext uc; 126 u16 retcode[8]; 127 }; 128 129 #ifdef CONFIG_SH_FPU 130 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc) 131 { 132 struct task_struct *tsk = current; 133 134 if (!(boot_cpu_data.flags & CPU_HAS_FPU)) 135 return 0; 136 137 set_used_math(); 138 return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0], 139 sizeof(long)*(16*2+2)); 140 } 141 142 static inline int save_sigcontext_fpu(struct sigcontext __user *sc, 143 struct pt_regs *regs) 144 { 145 struct task_struct *tsk = current; 146 147 if (!(boot_cpu_data.flags & CPU_HAS_FPU)) 148 return 0; 149 150 if (!used_math()) 151 return __put_user(0, &sc->sc_ownedfp); 152 153 if (__put_user(1, &sc->sc_ownedfp)) 154 return -EFAULT; 155 156 /* This will cause a "finit" to be triggered by the next 157 attempted FPU operation by the 'current' process. 158 */ 159 clear_used_math(); 160 161 unlazy_fpu(tsk, regs); 162 return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu, 163 sizeof(long)*(16*2+2)); 164 } 165 #endif /* CONFIG_SH_FPU */ 166 167 static int 168 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) 169 { 170 unsigned int err = 0; 171 172 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) 173 COPY(regs[1]); 174 COPY(regs[2]); COPY(regs[3]); 175 COPY(regs[4]); COPY(regs[5]); 176 COPY(regs[6]); COPY(regs[7]); 177 COPY(regs[8]); COPY(regs[9]); 178 COPY(regs[10]); COPY(regs[11]); 179 COPY(regs[12]); COPY(regs[13]); 180 COPY(regs[14]); COPY(regs[15]); 181 COPY(gbr); COPY(mach); 182 COPY(macl); COPY(pr); 183 COPY(sr); COPY(pc); 184 #undef COPY 185 186 #ifdef CONFIG_SH_FPU 187 if (boot_cpu_data.flags & CPU_HAS_FPU) { 188 int owned_fp; 189 struct task_struct *tsk = current; 190 191 regs->sr |= SR_FD; /* Release FPU */ 192 clear_fpu(tsk, regs); 193 clear_used_math(); 194 err |= __get_user (owned_fp, &sc->sc_ownedfp); 195 if (owned_fp) 196 err |= restore_sigcontext_fpu(sc); 197 } 198 #endif 199 200 regs->tra = -1; /* disable syscall checks */ 201 err |= __get_user(*r0_p, &sc->sc_regs[0]); 202 return err; 203 } 204 205 asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5, 206 unsigned long r6, unsigned long r7, 207 struct pt_regs __regs) 208 { 209 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 210 struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15]; 211 sigset_t set; 212 int r0; 213 214 /* Always make any pending restarted system calls return -EINTR */ 215 current_thread_info()->restart_block.fn = do_no_restart_syscall; 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 set_current_blocked(&set); 227 228 if (restore_sigcontext(regs, &frame->sc, &r0)) 229 goto badframe; 230 return r0; 231 232 badframe: 233 force_sig(SIGSEGV, current); 234 return 0; 235 } 236 237 asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5, 238 unsigned long r6, unsigned long r7, 239 struct pt_regs __regs) 240 { 241 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 242 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15]; 243 sigset_t set; 244 int r0; 245 246 /* Always make any pending restarted system calls return -EINTR */ 247 current_thread_info()->restart_block.fn = do_no_restart_syscall; 248 249 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 250 goto badframe; 251 252 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 253 goto badframe; 254 255 set_current_blocked(&set); 256 257 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) 258 goto badframe; 259 260 if (do_sigaltstack(&frame->uc.uc_stack, NULL, 261 regs->regs[15]) == -EFAULT) 262 goto badframe; 263 264 return r0; 265 266 badframe: 267 force_sig(SIGSEGV, current); 268 return 0; 269 } 270 271 /* 272 * Set up a signal frame. 273 */ 274 275 static int 276 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 277 unsigned long mask) 278 { 279 int err = 0; 280 281 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) 282 COPY(regs[0]); COPY(regs[1]); 283 COPY(regs[2]); COPY(regs[3]); 284 COPY(regs[4]); COPY(regs[5]); 285 COPY(regs[6]); COPY(regs[7]); 286 COPY(regs[8]); COPY(regs[9]); 287 COPY(regs[10]); COPY(regs[11]); 288 COPY(regs[12]); COPY(regs[13]); 289 COPY(regs[14]); COPY(regs[15]); 290 COPY(gbr); COPY(mach); 291 COPY(macl); COPY(pr); 292 COPY(sr); COPY(pc); 293 #undef COPY 294 295 #ifdef CONFIG_SH_FPU 296 err |= save_sigcontext_fpu(sc, regs); 297 #endif 298 299 /* non-iBCS2 extensions.. */ 300 err |= __put_user(mask, &sc->oldmask); 301 302 return err; 303 } 304 305 /* 306 * Determine which stack to use.. 307 */ 308 static inline void __user * 309 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) 310 { 311 if (ka->sa.sa_flags & SA_ONSTACK) { 312 if (sas_ss_flags(sp) == 0) 313 sp = current->sas_ss_sp + current->sas_ss_size; 314 } 315 316 return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul); 317 } 318 319 /* These symbols are defined with the addresses in the vsyscall page. 320 See vsyscall-trapa.S. */ 321 extern void __kernel_sigreturn(void); 322 extern void __kernel_rt_sigreturn(void); 323 324 static int setup_frame(int sig, struct k_sigaction *ka, 325 sigset_t *set, struct pt_regs *regs) 326 { 327 struct sigframe __user *frame; 328 int err = 0; 329 int signal; 330 331 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); 332 333 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 334 goto give_sigsegv; 335 336 signal = current_thread_info()->exec_domain 337 && current_thread_info()->exec_domain->signal_invmap 338 && sig < 32 339 ? current_thread_info()->exec_domain->signal_invmap[sig] 340 : sig; 341 342 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); 343 344 if (_NSIG_WORDS > 1) 345 err |= __copy_to_user(frame->extramask, &set->sig[1], 346 sizeof(frame->extramask)); 347 348 /* Set up to return from userspace. If provided, use a stub 349 already in userspace. */ 350 if (ka->sa.sa_flags & SA_RESTORER) { 351 regs->pr = (unsigned long) ka->sa.sa_restorer; 352 #ifdef CONFIG_VSYSCALL 353 } else if (likely(current->mm->context.vdso)) { 354 regs->pr = VDSO_SYM(&__kernel_sigreturn); 355 #endif 356 } else { 357 /* Generate return code (system call to sigreturn) */ 358 err |= __put_user(MOVW(7), &frame->retcode[0]); 359 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 360 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 361 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 362 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 363 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 364 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 365 err |= __put_user((__NR_sigreturn), &frame->retcode[7]); 366 regs->pr = (unsigned long) frame->retcode; 367 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 368 } 369 370 if (err) 371 goto give_sigsegv; 372 373 /* Set up registers for signal handler */ 374 regs->regs[15] = (unsigned long) frame; 375 regs->regs[4] = signal; /* Arg for signal handler */ 376 regs->regs[5] = 0; 377 regs->regs[6] = (unsigned long) &frame->sc; 378 379 if (current->personality & FDPIC_FUNCPTRS) { 380 struct fdpic_func_descriptor __user *funcptr = 381 (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; 382 383 err |= __get_user(regs->pc, &funcptr->text); 384 err |= __get_user(regs->regs[12], &funcptr->GOT); 385 } else 386 regs->pc = (unsigned long)ka->sa.sa_handler; 387 388 if (err) 389 goto give_sigsegv; 390 391 set_fs(USER_DS); 392 393 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 394 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 395 396 return 0; 397 398 give_sigsegv: 399 force_sigsegv(sig, current); 400 return -EFAULT; 401 } 402 403 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, 404 sigset_t *set, struct pt_regs *regs) 405 { 406 struct rt_sigframe __user *frame; 407 int err = 0; 408 int signal; 409 410 frame = get_sigframe(ka, regs->regs[15], sizeof(*frame)); 411 412 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 413 goto give_sigsegv; 414 415 signal = current_thread_info()->exec_domain 416 && current_thread_info()->exec_domain->signal_invmap 417 && sig < 32 418 ? current_thread_info()->exec_domain->signal_invmap[sig] 419 : sig; 420 421 err |= copy_siginfo_to_user(&frame->info, info); 422 423 /* Create the ucontext. */ 424 err |= __put_user(0, &frame->uc.uc_flags); 425 err |= __put_user(NULL, &frame->uc.uc_link); 426 err |= __put_user((void *)current->sas_ss_sp, 427 &frame->uc.uc_stack.ss_sp); 428 err |= __put_user(sas_ss_flags(regs->regs[15]), 429 &frame->uc.uc_stack.ss_flags); 430 err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); 431 err |= setup_sigcontext(&frame->uc.uc_mcontext, 432 regs, set->sig[0]); 433 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 434 435 /* Set up to return from userspace. If provided, use a stub 436 already in userspace. */ 437 if (ka->sa.sa_flags & SA_RESTORER) { 438 regs->pr = (unsigned long) ka->sa.sa_restorer; 439 #ifdef CONFIG_VSYSCALL 440 } else if (likely(current->mm->context.vdso)) { 441 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn); 442 #endif 443 } else { 444 /* Generate return code (system call to rt_sigreturn) */ 445 err |= __put_user(MOVW(7), &frame->retcode[0]); 446 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 447 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 448 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 449 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 450 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 451 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 452 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]); 453 regs->pr = (unsigned long) frame->retcode; 454 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 455 } 456 457 if (err) 458 goto give_sigsegv; 459 460 /* Set up registers for signal handler */ 461 regs->regs[15] = (unsigned long) frame; 462 regs->regs[4] = signal; /* Arg for signal handler */ 463 regs->regs[5] = (unsigned long) &frame->info; 464 regs->regs[6] = (unsigned long) &frame->uc; 465 466 if (current->personality & FDPIC_FUNCPTRS) { 467 struct fdpic_func_descriptor __user *funcptr = 468 (struct fdpic_func_descriptor __user *)ka->sa.sa_handler; 469 470 err |= __get_user(regs->pc, &funcptr->text); 471 err |= __get_user(regs->regs[12], &funcptr->GOT); 472 } else 473 regs->pc = (unsigned long)ka->sa.sa_handler; 474 475 if (err) 476 goto give_sigsegv; 477 478 set_fs(USER_DS); 479 480 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 481 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 482 483 return 0; 484 485 give_sigsegv: 486 force_sigsegv(sig, current); 487 return -EFAULT; 488 } 489 490 static inline void 491 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs, 492 struct sigaction *sa) 493 { 494 /* If we're not from a syscall, bail out */ 495 if (regs->tra < 0) 496 return; 497 498 /* check for system call restart.. */ 499 switch (regs->regs[0]) { 500 case -ERESTART_RESTARTBLOCK: 501 case -ERESTARTNOHAND: 502 no_system_call_restart: 503 regs->regs[0] = -EINTR; 504 break; 505 506 case -ERESTARTSYS: 507 if (!(sa->sa_flags & SA_RESTART)) 508 goto no_system_call_restart; 509 /* fallthrough */ 510 case -ERESTARTNOINTR: 511 regs->regs[0] = save_r0; 512 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 513 break; 514 } 515 } 516 517 /* 518 * OK, we're invoking a handler 519 */ 520 static void 521 handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, 522 struct pt_regs *regs, unsigned int save_r0) 523 { 524 sigset_t *oldset = sigmask_to_save(); 525 int ret; 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 (ret) 534 return; 535 signal_delivered(sig, info, ka, regs, 536 test_thread_flag(TIF_SINGLESTEP)); 537 } 538 539 /* 540 * Note that 'init' is a special process: it doesn't get signals it doesn't 541 * want to handle. Thus you cannot kill init even with a SIGKILL even by 542 * mistake. 543 * 544 * Note that we go through the signals twice: once to check the signals that 545 * the kernel can handle, and then we build all the user-level signal handling 546 * stack-frames in one go after that. 547 */ 548 static void do_signal(struct pt_regs *regs, unsigned int save_r0) 549 { 550 siginfo_t info; 551 int signr; 552 struct k_sigaction ka; 553 554 /* 555 * We want the common case to go fast, which 556 * is why we may in certain cases get here from 557 * kernel mode. Just return without doing anything 558 * if so. 559 */ 560 if (!user_mode(regs)) 561 return; 562 563 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 564 if (signr > 0) { 565 handle_syscall_restart(save_r0, regs, &ka.sa); 566 567 /* Whee! Actually deliver the signal. */ 568 handle_signal(signr, &ka, &info, regs, save_r0); 569 return; 570 } 571 572 /* Did we come from a system call? */ 573 if (regs->tra >= 0) { 574 /* Restart the system call - no handlers present */ 575 if (regs->regs[0] == -ERESTARTNOHAND || 576 regs->regs[0] == -ERESTARTSYS || 577 regs->regs[0] == -ERESTARTNOINTR) { 578 regs->regs[0] = save_r0; 579 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 580 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { 581 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 582 regs->regs[3] = __NR_restart_syscall; 583 } 584 } 585 586 /* 587 * If there's no signal to deliver, we just put the saved sigmask 588 * back. 589 */ 590 restore_saved_sigmask(); 591 } 592 593 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, 594 unsigned long thread_info_flags) 595 { 596 /* deal with pending signal delivery */ 597 if (thread_info_flags & _TIF_SIGPENDING) 598 do_signal(regs, save_r0); 599 600 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 601 clear_thread_flag(TIF_NOTIFY_RESUME); 602 tracehook_notify_resume(regs); 603 } 604 } 605