1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 1991, 1992 Linus Torvalds 7 * Copyright (C) 1994 - 2000 Ralf Baechle 8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc. 9 */ 10 #include <linux/cache.h> 11 #include <linux/irqflags.h> 12 #include <linux/sched.h> 13 #include <linux/mm.h> 14 #include <linux/personality.h> 15 #include <linux/smp.h> 16 #include <linux/kernel.h> 17 #include <linux/signal.h> 18 #include <linux/errno.h> 19 #include <linux/wait.h> 20 #include <linux/ptrace.h> 21 #include <linux/unistd.h> 22 #include <linux/compiler.h> 23 #include <linux/syscalls.h> 24 #include <linux/uaccess.h> 25 #include <linux/tracehook.h> 26 27 #include <asm/abi.h> 28 #include <asm/asm.h> 29 #include <linux/bitops.h> 30 #include <asm/cacheflush.h> 31 #include <asm/fpu.h> 32 #include <asm/sim.h> 33 #include <asm/ucontext.h> 34 #include <asm/cpu-features.h> 35 #include <asm/war.h> 36 #include <asm/vdso.h> 37 #include <asm/dsp.h> 38 39 #include "signal-common.h" 40 41 static int (*save_fp_context)(struct sigcontext __user *sc); 42 static int (*restore_fp_context)(struct sigcontext __user *sc); 43 44 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc); 45 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc); 46 47 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc); 48 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc); 49 50 struct sigframe { 51 u32 sf_ass[4]; /* argument save space for o32 */ 52 u32 sf_pad[2]; /* Was: signal trampoline */ 53 struct sigcontext sf_sc; 54 sigset_t sf_mask; 55 }; 56 57 struct rt_sigframe { 58 u32 rs_ass[4]; /* argument save space for o32 */ 59 u32 rs_pad[2]; /* Was: signal trampoline */ 60 struct siginfo rs_info; 61 struct ucontext rs_uc; 62 }; 63 64 /* 65 * Helper routines 66 */ 67 static int protected_save_fp_context(struct sigcontext __user *sc) 68 { 69 int err; 70 while (1) { 71 lock_fpu_owner(); 72 own_fpu_inatomic(1); 73 err = save_fp_context(sc); /* this might fail */ 74 unlock_fpu_owner(); 75 if (likely(!err)) 76 break; 77 /* touch the sigcontext and try again */ 78 err = __put_user(0, &sc->sc_fpregs[0]) | 79 __put_user(0, &sc->sc_fpregs[31]) | 80 __put_user(0, &sc->sc_fpc_csr); 81 if (err) 82 break; /* really bad sigcontext */ 83 } 84 return err; 85 } 86 87 static int protected_restore_fp_context(struct sigcontext __user *sc) 88 { 89 int err, tmp __maybe_unused; 90 while (1) { 91 lock_fpu_owner(); 92 own_fpu_inatomic(0); 93 err = restore_fp_context(sc); /* this might fail */ 94 unlock_fpu_owner(); 95 if (likely(!err)) 96 break; 97 /* touch the sigcontext and try again */ 98 err = __get_user(tmp, &sc->sc_fpregs[0]) | 99 __get_user(tmp, &sc->sc_fpregs[31]) | 100 __get_user(tmp, &sc->sc_fpc_csr); 101 if (err) 102 break; /* really bad sigcontext */ 103 } 104 return err; 105 } 106 107 int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 108 { 109 int err = 0; 110 int i; 111 unsigned int used_math; 112 113 err |= __put_user(regs->cp0_epc, &sc->sc_pc); 114 115 err |= __put_user(0, &sc->sc_regs[0]); 116 for (i = 1; i < 32; i++) 117 err |= __put_user(regs->regs[i], &sc->sc_regs[i]); 118 119 #ifdef CONFIG_CPU_HAS_SMARTMIPS 120 err |= __put_user(regs->acx, &sc->sc_acx); 121 #endif 122 err |= __put_user(regs->hi, &sc->sc_mdhi); 123 err |= __put_user(regs->lo, &sc->sc_mdlo); 124 if (cpu_has_dsp) { 125 err |= __put_user(mfhi1(), &sc->sc_hi1); 126 err |= __put_user(mflo1(), &sc->sc_lo1); 127 err |= __put_user(mfhi2(), &sc->sc_hi2); 128 err |= __put_user(mflo2(), &sc->sc_lo2); 129 err |= __put_user(mfhi3(), &sc->sc_hi3); 130 err |= __put_user(mflo3(), &sc->sc_lo3); 131 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp); 132 } 133 134 used_math = !!used_math(); 135 err |= __put_user(used_math, &sc->sc_used_math); 136 137 if (used_math) { 138 /* 139 * Save FPU state to signal context. Signal handler 140 * will "inherit" current FPU state. 141 */ 142 err |= protected_save_fp_context(sc); 143 } 144 return err; 145 } 146 147 int fpcsr_pending(unsigned int __user *fpcsr) 148 { 149 int err, sig = 0; 150 unsigned int csr, enabled; 151 152 err = __get_user(csr, fpcsr); 153 enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5); 154 /* 155 * If the signal handler set some FPU exceptions, clear it and 156 * send SIGFPE. 157 */ 158 if (csr & enabled) { 159 csr &= ~enabled; 160 err |= __put_user(csr, fpcsr); 161 sig = SIGFPE; 162 } 163 return err ?: sig; 164 } 165 166 static int 167 check_and_restore_fp_context(struct sigcontext __user *sc) 168 { 169 int err, sig; 170 171 err = sig = fpcsr_pending(&sc->sc_fpc_csr); 172 if (err > 0) 173 err = 0; 174 err |= protected_restore_fp_context(sc); 175 return err ?: sig; 176 } 177 178 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 179 { 180 unsigned int used_math; 181 unsigned long treg; 182 int err = 0; 183 int i; 184 185 /* Always make any pending restarted system calls return -EINTR */ 186 current_thread_info()->restart_block.fn = do_no_restart_syscall; 187 188 err |= __get_user(regs->cp0_epc, &sc->sc_pc); 189 190 #ifdef CONFIG_CPU_HAS_SMARTMIPS 191 err |= __get_user(regs->acx, &sc->sc_acx); 192 #endif 193 err |= __get_user(regs->hi, &sc->sc_mdhi); 194 err |= __get_user(regs->lo, &sc->sc_mdlo); 195 if (cpu_has_dsp) { 196 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg); 197 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg); 198 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg); 199 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg); 200 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg); 201 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg); 202 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK); 203 } 204 205 for (i = 1; i < 32; i++) 206 err |= __get_user(regs->regs[i], &sc->sc_regs[i]); 207 208 err |= __get_user(used_math, &sc->sc_used_math); 209 conditional_used_math(used_math); 210 211 if (used_math) { 212 /* restore fpu context if we have used it before */ 213 if (!err) 214 err = check_and_restore_fp_context(sc); 215 } else { 216 /* signal handler may have used FPU. Give it up. */ 217 lose_fpu(0); 218 } 219 220 return err; 221 } 222 223 void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, 224 size_t frame_size) 225 { 226 unsigned long sp; 227 228 /* Default to using normal stack */ 229 sp = regs->regs[29]; 230 231 /* 232 * FPU emulator may have it's own trampoline active just 233 * above the user stack, 16-bytes before the next lowest 234 * 16 byte boundary. Try to avoid trashing it. 235 */ 236 sp -= 32; 237 238 /* This is the X/Open sanctioned signal stack switching. */ 239 if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0)) 240 sp = current->sas_ss_sp + current->sas_ss_size; 241 242 return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK)); 243 } 244 245 /* 246 * Atomically swap in the new signal mask, and wait for a signal. 247 */ 248 249 #ifdef CONFIG_TRAD_SIGNALS 250 asmlinkage int sys_sigsuspend(nabi_no_regargs struct pt_regs regs) 251 { 252 sigset_t newset; 253 sigset_t __user *uset; 254 255 uset = (sigset_t __user *) regs.regs[4]; 256 if (copy_from_user(&newset, uset, sizeof(sigset_t))) 257 return -EFAULT; 258 return sigsuspend(&newset); 259 } 260 #endif 261 262 asmlinkage int sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs) 263 { 264 sigset_t newset; 265 sigset_t __user *unewset; 266 size_t sigsetsize; 267 268 /* XXX Don't preclude handling different sized sigset_t's. */ 269 sigsetsize = regs.regs[5]; 270 if (sigsetsize != sizeof(sigset_t)) 271 return -EINVAL; 272 273 unewset = (sigset_t __user *) regs.regs[4]; 274 if (copy_from_user(&newset, unewset, sizeof(newset))) 275 return -EFAULT; 276 return sigsuspend(&newset); 277 } 278 279 #ifdef CONFIG_TRAD_SIGNALS 280 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act, 281 struct sigaction __user *, oact) 282 { 283 struct k_sigaction new_ka, old_ka; 284 int ret; 285 int err = 0; 286 287 if (act) { 288 old_sigset_t mask; 289 290 if (!access_ok(VERIFY_READ, act, sizeof(*act))) 291 return -EFAULT; 292 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler); 293 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags); 294 err |= __get_user(mask, &act->sa_mask.sig[0]); 295 if (err) 296 return -EFAULT; 297 298 siginitset(&new_ka.sa.sa_mask, mask); 299 } 300 301 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 302 303 if (!ret && oact) { 304 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact))) 305 return -EFAULT; 306 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 307 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler); 308 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig); 309 err |= __put_user(0, &oact->sa_mask.sig[1]); 310 err |= __put_user(0, &oact->sa_mask.sig[2]); 311 err |= __put_user(0, &oact->sa_mask.sig[3]); 312 if (err) 313 return -EFAULT; 314 } 315 316 return ret; 317 } 318 #endif 319 320 asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs) 321 { 322 const stack_t __user *uss = (const stack_t __user *) regs.regs[4]; 323 stack_t __user *uoss = (stack_t __user *) regs.regs[5]; 324 unsigned long usp = regs.regs[29]; 325 326 return do_sigaltstack(uss, uoss, usp); 327 } 328 329 #ifdef CONFIG_TRAD_SIGNALS 330 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs) 331 { 332 struct sigframe __user *frame; 333 sigset_t blocked; 334 int sig; 335 336 frame = (struct sigframe __user *) regs.regs[29]; 337 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 338 goto badframe; 339 if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked))) 340 goto badframe; 341 342 set_current_blocked(&blocked); 343 344 sig = restore_sigcontext(®s, &frame->sf_sc); 345 if (sig < 0) 346 goto badframe; 347 else if (sig) 348 force_sig(sig, current); 349 350 /* 351 * Don't let your children do this ... 352 */ 353 __asm__ __volatile__( 354 "move\t$29, %0\n\t" 355 "j\tsyscall_exit" 356 :/* no outputs */ 357 :"r" (®s)); 358 /* Unreached */ 359 360 badframe: 361 force_sig(SIGSEGV, current); 362 } 363 #endif /* CONFIG_TRAD_SIGNALS */ 364 365 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs) 366 { 367 struct rt_sigframe __user *frame; 368 sigset_t set; 369 int sig; 370 371 frame = (struct rt_sigframe __user *) regs.regs[29]; 372 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 373 goto badframe; 374 if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set))) 375 goto badframe; 376 377 set_current_blocked(&set); 378 379 sig = restore_sigcontext(®s, &frame->rs_uc.uc_mcontext); 380 if (sig < 0) 381 goto badframe; 382 else if (sig) 383 force_sig(sig, current); 384 385 /* It is more difficult to avoid calling this function than to 386 call it and ignore errors. */ 387 do_sigaltstack(&frame->rs_uc.uc_stack, NULL, regs.regs[29]); 388 389 /* 390 * Don't let your children do this ... 391 */ 392 __asm__ __volatile__( 393 "move\t$29, %0\n\t" 394 "j\tsyscall_exit" 395 :/* no outputs */ 396 :"r" (®s)); 397 /* Unreached */ 398 399 badframe: 400 force_sig(SIGSEGV, current); 401 } 402 403 #ifdef CONFIG_TRAD_SIGNALS 404 static int setup_frame(void *sig_return, struct k_sigaction *ka, 405 struct pt_regs *regs, int signr, sigset_t *set) 406 { 407 struct sigframe __user *frame; 408 int err = 0; 409 410 frame = get_sigframe(ka, regs, sizeof(*frame)); 411 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) 412 goto give_sigsegv; 413 414 err |= setup_sigcontext(regs, &frame->sf_sc); 415 err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set)); 416 if (err) 417 goto give_sigsegv; 418 419 /* 420 * Arguments to signal handler: 421 * 422 * a0 = signal number 423 * a1 = 0 (should be cause) 424 * a2 = pointer to struct sigcontext 425 * 426 * $25 and c0_epc point to the signal handler, $29 points to the 427 * struct sigframe. 428 */ 429 regs->regs[ 4] = signr; 430 regs->regs[ 5] = 0; 431 regs->regs[ 6] = (unsigned long) &frame->sf_sc; 432 regs->regs[29] = (unsigned long) frame; 433 regs->regs[31] = (unsigned long) sig_return; 434 regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler; 435 436 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", 437 current->comm, current->pid, 438 frame, regs->cp0_epc, regs->regs[31]); 439 return 0; 440 441 give_sigsegv: 442 force_sigsegv(signr, current); 443 return -EFAULT; 444 } 445 #endif 446 447 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka, 448 struct pt_regs *regs, int signr, sigset_t *set, 449 siginfo_t *info) 450 { 451 struct rt_sigframe __user *frame; 452 int err = 0; 453 454 frame = get_sigframe(ka, regs, sizeof(*frame)); 455 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) 456 goto give_sigsegv; 457 458 /* Create siginfo. */ 459 err |= copy_siginfo_to_user(&frame->rs_info, info); 460 461 /* Create the ucontext. */ 462 err |= __put_user(0, &frame->rs_uc.uc_flags); 463 err |= __put_user(NULL, &frame->rs_uc.uc_link); 464 err |= __put_user((void __user *)current->sas_ss_sp, 465 &frame->rs_uc.uc_stack.ss_sp); 466 err |= __put_user(sas_ss_flags(regs->regs[29]), 467 &frame->rs_uc.uc_stack.ss_flags); 468 err |= __put_user(current->sas_ss_size, 469 &frame->rs_uc.uc_stack.ss_size); 470 err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext); 471 err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)); 472 473 if (err) 474 goto give_sigsegv; 475 476 /* 477 * Arguments to signal handler: 478 * 479 * a0 = signal number 480 * a1 = 0 (should be cause) 481 * a2 = pointer to ucontext 482 * 483 * $25 and c0_epc point to the signal handler, $29 points to 484 * the struct rt_sigframe. 485 */ 486 regs->regs[ 4] = signr; 487 regs->regs[ 5] = (unsigned long) &frame->rs_info; 488 regs->regs[ 6] = (unsigned long) &frame->rs_uc; 489 regs->regs[29] = (unsigned long) frame; 490 regs->regs[31] = (unsigned long) sig_return; 491 regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler; 492 493 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", 494 current->comm, current->pid, 495 frame, regs->cp0_epc, regs->regs[31]); 496 497 return 0; 498 499 give_sigsegv: 500 force_sigsegv(signr, current); 501 return -EFAULT; 502 } 503 504 struct mips_abi mips_abi = { 505 #ifdef CONFIG_TRAD_SIGNALS 506 .setup_frame = setup_frame, 507 .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline), 508 #endif 509 .setup_rt_frame = setup_rt_frame, 510 .rt_signal_return_offset = 511 offsetof(struct mips_vdso, rt_signal_trampoline), 512 .restart = __NR_restart_syscall 513 }; 514 515 static void handle_signal(unsigned long sig, siginfo_t *info, 516 struct k_sigaction *ka, struct pt_regs *regs) 517 { 518 sigset_t *oldset = sigmask_to_save(); 519 int ret; 520 struct mips_abi *abi = current->thread.abi; 521 void *vdso = current->mm->context.vdso; 522 523 if (regs->regs[0]) { 524 switch(regs->regs[2]) { 525 case ERESTART_RESTARTBLOCK: 526 case ERESTARTNOHAND: 527 regs->regs[2] = EINTR; 528 break; 529 case ERESTARTSYS: 530 if (!(ka->sa.sa_flags & SA_RESTART)) { 531 regs->regs[2] = EINTR; 532 break; 533 } 534 /* fallthrough */ 535 case ERESTARTNOINTR: 536 regs->regs[7] = regs->regs[26]; 537 regs->regs[2] = regs->regs[0]; 538 regs->cp0_epc -= 4; 539 } 540 541 regs->regs[0] = 0; /* Don't deal with this again. */ 542 } 543 544 if (sig_uses_siginfo(ka)) 545 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset, 546 ka, regs, sig, oldset, info); 547 else 548 ret = abi->setup_frame(vdso + abi->signal_return_offset, 549 ka, regs, sig, oldset); 550 551 if (ret) 552 return; 553 554 signal_delivered(sig, info, ka, regs, 0); 555 } 556 557 static void do_signal(struct pt_regs *regs) 558 { 559 struct k_sigaction ka; 560 siginfo_t info; 561 int signr; 562 563 /* 564 * We want the common case to go fast, which is why we may in certain 565 * cases get here from kernel mode. Just return without doing anything 566 * if so. 567 */ 568 if (!user_mode(regs)) 569 return; 570 571 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 572 if (signr > 0) { 573 /* Whee! Actually deliver the signal. */ 574 handle_signal(signr, &info, &ka, regs); 575 return; 576 } 577 578 if (regs->regs[0]) { 579 if (regs->regs[2] == ERESTARTNOHAND || 580 regs->regs[2] == ERESTARTSYS || 581 regs->regs[2] == ERESTARTNOINTR) { 582 regs->regs[2] = regs->regs[0]; 583 regs->regs[7] = regs->regs[26]; 584 regs->cp0_epc -= 4; 585 } 586 if (regs->regs[2] == ERESTART_RESTARTBLOCK) { 587 regs->regs[2] = current->thread.abi->restart; 588 regs->regs[7] = regs->regs[26]; 589 regs->cp0_epc -= 4; 590 } 591 regs->regs[0] = 0; /* Don't deal with this again. */ 592 } 593 594 /* 595 * If there's no signal to deliver, we just put the saved sigmask 596 * back 597 */ 598 restore_saved_sigmask(); 599 } 600 601 /* 602 * notification of userspace execution resumption 603 * - triggered by the TIF_WORK_MASK flags 604 */ 605 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused, 606 __u32 thread_info_flags) 607 { 608 local_irq_enable(); 609 610 /* deal with pending signal delivery */ 611 if (thread_info_flags & _TIF_SIGPENDING) 612 do_signal(regs); 613 614 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 615 clear_thread_flag(TIF_NOTIFY_RESUME); 616 tracehook_notify_resume(regs); 617 } 618 } 619 620 #ifdef CONFIG_SMP 621 static int smp_save_fp_context(struct sigcontext __user *sc) 622 { 623 return raw_cpu_has_fpu 624 ? _save_fp_context(sc) 625 : fpu_emulator_save_context(sc); 626 } 627 628 static int smp_restore_fp_context(struct sigcontext __user *sc) 629 { 630 return raw_cpu_has_fpu 631 ? _restore_fp_context(sc) 632 : fpu_emulator_restore_context(sc); 633 } 634 #endif 635 636 static int signal_setup(void) 637 { 638 #ifdef CONFIG_SMP 639 /* For now just do the cpu_has_fpu check when the functions are invoked */ 640 save_fp_context = smp_save_fp_context; 641 restore_fp_context = smp_restore_fp_context; 642 #else 643 if (cpu_has_fpu) { 644 save_fp_context = _save_fp_context; 645 restore_fp_context = _restore_fp_context; 646 } else { 647 save_fp_context = fpu_emulator_save_context; 648 restore_fp_context = fpu_emulator_restore_context; 649 } 650 #endif 651 652 return 0; 653 } 654 655 arch_initcall(signal_setup); 656