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 SYSCALL_DEFINE1(sigsuspend, sigset_t __user *, uset) 251 { 252 return sys_rt_sigsuspend(uset, sizeof(sigset_t)); 253 } 254 #endif 255 256 #ifdef CONFIG_TRAD_SIGNALS 257 SYSCALL_DEFINE3(sigaction, int, sig, const struct sigaction __user *, act, 258 struct sigaction __user *, oact) 259 { 260 struct k_sigaction new_ka, old_ka; 261 int ret; 262 int err = 0; 263 264 if (act) { 265 old_sigset_t mask; 266 267 if (!access_ok(VERIFY_READ, act, sizeof(*act))) 268 return -EFAULT; 269 err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler); 270 err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags); 271 err |= __get_user(mask, &act->sa_mask.sig[0]); 272 if (err) 273 return -EFAULT; 274 275 siginitset(&new_ka.sa.sa_mask, mask); 276 } 277 278 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 279 280 if (!ret && oact) { 281 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact))) 282 return -EFAULT; 283 err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 284 err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler); 285 err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig); 286 err |= __put_user(0, &oact->sa_mask.sig[1]); 287 err |= __put_user(0, &oact->sa_mask.sig[2]); 288 err |= __put_user(0, &oact->sa_mask.sig[3]); 289 if (err) 290 return -EFAULT; 291 } 292 293 return ret; 294 } 295 #endif 296 297 #ifdef CONFIG_TRAD_SIGNALS 298 asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs) 299 { 300 struct sigframe __user *frame; 301 sigset_t blocked; 302 int sig; 303 304 frame = (struct sigframe __user *) regs.regs[29]; 305 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 306 goto badframe; 307 if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked))) 308 goto badframe; 309 310 set_current_blocked(&blocked); 311 312 sig = restore_sigcontext(®s, &frame->sf_sc); 313 if (sig < 0) 314 goto badframe; 315 else if (sig) 316 force_sig(sig, current); 317 318 /* 319 * Don't let your children do this ... 320 */ 321 __asm__ __volatile__( 322 "move\t$29, %0\n\t" 323 "j\tsyscall_exit" 324 :/* no outputs */ 325 :"r" (®s)); 326 /* Unreached */ 327 328 badframe: 329 force_sig(SIGSEGV, current); 330 } 331 #endif /* CONFIG_TRAD_SIGNALS */ 332 333 asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs) 334 { 335 struct rt_sigframe __user *frame; 336 sigset_t set; 337 int sig; 338 339 frame = (struct rt_sigframe __user *) regs.regs[29]; 340 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 341 goto badframe; 342 if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set))) 343 goto badframe; 344 345 set_current_blocked(&set); 346 347 sig = restore_sigcontext(®s, &frame->rs_uc.uc_mcontext); 348 if (sig < 0) 349 goto badframe; 350 else if (sig) 351 force_sig(sig, current); 352 353 if (restore_altstack(&frame->rs_uc.uc_stack)) 354 goto badframe; 355 356 /* 357 * Don't let your children do this ... 358 */ 359 __asm__ __volatile__( 360 "move\t$29, %0\n\t" 361 "j\tsyscall_exit" 362 :/* no outputs */ 363 :"r" (®s)); 364 /* Unreached */ 365 366 badframe: 367 force_sig(SIGSEGV, current); 368 } 369 370 #ifdef CONFIG_TRAD_SIGNALS 371 static int setup_frame(void *sig_return, struct k_sigaction *ka, 372 struct pt_regs *regs, int signr, sigset_t *set) 373 { 374 struct sigframe __user *frame; 375 int err = 0; 376 377 frame = get_sigframe(ka, regs, sizeof(*frame)); 378 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) 379 goto give_sigsegv; 380 381 err |= setup_sigcontext(regs, &frame->sf_sc); 382 err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set)); 383 if (err) 384 goto give_sigsegv; 385 386 /* 387 * Arguments to signal handler: 388 * 389 * a0 = signal number 390 * a1 = 0 (should be cause) 391 * a2 = pointer to struct sigcontext 392 * 393 * $25 and c0_epc point to the signal handler, $29 points to the 394 * struct sigframe. 395 */ 396 regs->regs[ 4] = signr; 397 regs->regs[ 5] = 0; 398 regs->regs[ 6] = (unsigned long) &frame->sf_sc; 399 regs->regs[29] = (unsigned long) frame; 400 regs->regs[31] = (unsigned long) sig_return; 401 regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler; 402 403 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", 404 current->comm, current->pid, 405 frame, regs->cp0_epc, regs->regs[31]); 406 return 0; 407 408 give_sigsegv: 409 force_sigsegv(signr, current); 410 return -EFAULT; 411 } 412 #endif 413 414 static int setup_rt_frame(void *sig_return, struct k_sigaction *ka, 415 struct pt_regs *regs, int signr, sigset_t *set, 416 siginfo_t *info) 417 { 418 struct rt_sigframe __user *frame; 419 int err = 0; 420 421 frame = get_sigframe(ka, regs, sizeof(*frame)); 422 if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame))) 423 goto give_sigsegv; 424 425 /* Create siginfo. */ 426 err |= copy_siginfo_to_user(&frame->rs_info, info); 427 428 /* Create the ucontext. */ 429 err |= __put_user(0, &frame->rs_uc.uc_flags); 430 err |= __put_user(NULL, &frame->rs_uc.uc_link); 431 err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]); 432 err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext); 433 err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set)); 434 435 if (err) 436 goto give_sigsegv; 437 438 /* 439 * Arguments to signal handler: 440 * 441 * a0 = signal number 442 * a1 = 0 (should be cause) 443 * a2 = pointer to ucontext 444 * 445 * $25 and c0_epc point to the signal handler, $29 points to 446 * the struct rt_sigframe. 447 */ 448 regs->regs[ 4] = signr; 449 regs->regs[ 5] = (unsigned long) &frame->rs_info; 450 regs->regs[ 6] = (unsigned long) &frame->rs_uc; 451 regs->regs[29] = (unsigned long) frame; 452 regs->regs[31] = (unsigned long) sig_return; 453 regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler; 454 455 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n", 456 current->comm, current->pid, 457 frame, regs->cp0_epc, regs->regs[31]); 458 459 return 0; 460 461 give_sigsegv: 462 force_sigsegv(signr, current); 463 return -EFAULT; 464 } 465 466 struct mips_abi mips_abi = { 467 #ifdef CONFIG_TRAD_SIGNALS 468 .setup_frame = setup_frame, 469 .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline), 470 #endif 471 .setup_rt_frame = setup_rt_frame, 472 .rt_signal_return_offset = 473 offsetof(struct mips_vdso, rt_signal_trampoline), 474 .restart = __NR_restart_syscall 475 }; 476 477 static void handle_signal(unsigned long sig, siginfo_t *info, 478 struct k_sigaction *ka, struct pt_regs *regs) 479 { 480 sigset_t *oldset = sigmask_to_save(); 481 int ret; 482 struct mips_abi *abi = current->thread.abi; 483 void *vdso = current->mm->context.vdso; 484 485 if (regs->regs[0]) { 486 switch(regs->regs[2]) { 487 case ERESTART_RESTARTBLOCK: 488 case ERESTARTNOHAND: 489 regs->regs[2] = EINTR; 490 break; 491 case ERESTARTSYS: 492 if (!(ka->sa.sa_flags & SA_RESTART)) { 493 regs->regs[2] = EINTR; 494 break; 495 } 496 /* fallthrough */ 497 case ERESTARTNOINTR: 498 regs->regs[7] = regs->regs[26]; 499 regs->regs[2] = regs->regs[0]; 500 regs->cp0_epc -= 4; 501 } 502 503 regs->regs[0] = 0; /* Don't deal with this again. */ 504 } 505 506 if (sig_uses_siginfo(ka)) 507 ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset, 508 ka, regs, sig, oldset, info); 509 else 510 ret = abi->setup_frame(vdso + abi->signal_return_offset, 511 ka, regs, sig, oldset); 512 513 if (ret) 514 return; 515 516 signal_delivered(sig, info, ka, regs, 0); 517 } 518 519 static void do_signal(struct pt_regs *regs) 520 { 521 struct k_sigaction ka; 522 siginfo_t info; 523 int signr; 524 525 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 526 if (signr > 0) { 527 /* Whee! Actually deliver the signal. */ 528 handle_signal(signr, &info, &ka, regs); 529 return; 530 } 531 532 if (regs->regs[0]) { 533 switch (regs->regs[2]) { 534 case ERESTARTNOHAND: 535 case ERESTARTSYS: 536 case ERESTARTNOINTR: 537 regs->regs[2] = regs->regs[0]; 538 regs->regs[7] = regs->regs[26]; 539 regs->cp0_epc -= 4; 540 break; 541 542 case ERESTART_RESTARTBLOCK: 543 regs->regs[2] = current->thread.abi->restart; 544 regs->regs[7] = regs->regs[26]; 545 regs->cp0_epc -= 4; 546 break; 547 } 548 regs->regs[0] = 0; /* Don't deal with this again. */ 549 } 550 551 /* 552 * If there's no signal to deliver, we just put the saved sigmask 553 * back 554 */ 555 restore_saved_sigmask(); 556 } 557 558 /* 559 * notification of userspace execution resumption 560 * - triggered by the TIF_WORK_MASK flags 561 */ 562 asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused, 563 __u32 thread_info_flags) 564 { 565 local_irq_enable(); 566 567 /* deal with pending signal delivery */ 568 if (thread_info_flags & _TIF_SIGPENDING) 569 do_signal(regs); 570 571 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 572 clear_thread_flag(TIF_NOTIFY_RESUME); 573 tracehook_notify_resume(regs); 574 } 575 } 576 577 #ifdef CONFIG_SMP 578 static int smp_save_fp_context(struct sigcontext __user *sc) 579 { 580 return raw_cpu_has_fpu 581 ? _save_fp_context(sc) 582 : fpu_emulator_save_context(sc); 583 } 584 585 static int smp_restore_fp_context(struct sigcontext __user *sc) 586 { 587 return raw_cpu_has_fpu 588 ? _restore_fp_context(sc) 589 : fpu_emulator_restore_context(sc); 590 } 591 #endif 592 593 static int signal_setup(void) 594 { 595 #ifdef CONFIG_SMP 596 /* For now just do the cpu_has_fpu check when the functions are invoked */ 597 save_fp_context = smp_save_fp_context; 598 restore_fp_context = smp_restore_fp_context; 599 #else 600 if (cpu_has_fpu) { 601 save_fp_context = _save_fp_context; 602 restore_fp_context = _restore_fp_context; 603 } else { 604 save_fp_context = fpu_emulator_save_context; 605 restore_fp_context = fpu_emulator_restore_context; 606 } 607 #endif 608 609 return 0; 610 } 611 612 arch_initcall(signal_setup); 613