Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/i386/i386/trap.c
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1 /*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the University of Utah, and William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 38 */ 39 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD: releng/8.2/sys/i386/i386/trap.c 215609 2010-11-21 10:00:43Z kib $"); 42 43 /* 44 * 386 Trap and System call handling 45 */ 46 47 #include "opt_clock.h" 48 #include "opt_cpu.h" 49 #include "opt_hwpmc_hooks.h" 50 #include "opt_isa.h" 51 #include "opt_kdb.h" 52 #include "opt_kdtrace.h" 53 #include "opt_ktrace.h" 54 #include "opt_npx.h" 55 #include "opt_trap.h" 56 57 #include <sys/param.h> 58 #include <sys/bus.h> 59 #include <sys/systm.h> 60 #include <sys/proc.h> 61 #include <sys/pioctl.h> 62 #include <sys/ptrace.h> 63 #include <sys/kdb.h> 64 #include <sys/kernel.h> 65 #include <sys/ktr.h> 66 #include <sys/lock.h> 67 #include <sys/mutex.h> 68 #include <sys/resourcevar.h> 69 #include <sys/signalvar.h> 70 #include <sys/syscall.h> 71 #include <sys/sysctl.h> 72 #include <sys/sysent.h> 73 #include <sys/uio.h> 74 #include <sys/vmmeter.h> 75 #ifdef KTRACE 76 #include <sys/ktrace.h> 77 #endif 78 #ifdef HWPMC_HOOKS 79 #include <sys/pmckern.h> 80 #endif 81 #include <security/audit/audit.h> 82 83 #include <vm/vm.h> 84 #include <vm/vm_param.h> 85 #include <vm/pmap.h> 86 #include <vm/vm_kern.h> 87 #include <vm/vm_map.h> 88 #include <vm/vm_page.h> 89 #include <vm/vm_extern.h> 90 91 #include <machine/cpu.h> 92 #include <machine/intr_machdep.h> 93 #include <machine/mca.h> 94 #include <machine/md_var.h> 95 #include <machine/pcb.h> 96 #ifdef SMP 97 #include <machine/smp.h> 98 #endif 99 #include <machine/tss.h> 100 #include <machine/vm86.h> 101 102 #ifdef POWERFAIL_NMI 103 #include <sys/syslog.h> 104 #include <machine/clock.h> 105 #endif 106 107 #ifdef KDTRACE_HOOKS 108 #include <sys/dtrace_bsd.h> 109 110 /* 111 * This is a hook which is initialised by the dtrace module 112 * to handle traps which might occur during DTrace probe 113 * execution. 114 */ 115 dtrace_trap_func_t dtrace_trap_func; 116 117 dtrace_doubletrap_func_t dtrace_doubletrap_func; 118 119 /* 120 * This is a hook which is initialised by the systrace module 121 * when it is loaded. This keeps the DTrace syscall provider 122 * implementation opaque. 123 */ 124 systrace_probe_func_t systrace_probe_func; 125 #endif 126 127 extern void trap(struct trapframe *frame); 128 extern void syscall(struct trapframe *frame); 129 130 static int trap_pfault(struct trapframe *, int, vm_offset_t); 131 static void trap_fatal(struct trapframe *, vm_offset_t); 132 void dblfault_handler(void); 133 134 extern inthand_t IDTVEC(lcall_syscall); 135 136 #define MAX_TRAP_MSG 30 137 static char *trap_msg[] = { 138 "", /* 0 unused */ 139 "privileged instruction fault", /* 1 T_PRIVINFLT */ 140 "", /* 2 unused */ 141 "breakpoint instruction fault", /* 3 T_BPTFLT */ 142 "", /* 4 unused */ 143 "", /* 5 unused */ 144 "arithmetic trap", /* 6 T_ARITHTRAP */ 145 "", /* 7 unused */ 146 "", /* 8 unused */ 147 "general protection fault", /* 9 T_PROTFLT */ 148 "trace trap", /* 10 T_TRCTRAP */ 149 "", /* 11 unused */ 150 "page fault", /* 12 T_PAGEFLT */ 151 "", /* 13 unused */ 152 "alignment fault", /* 14 T_ALIGNFLT */ 153 "", /* 15 unused */ 154 "", /* 16 unused */ 155 "", /* 17 unused */ 156 "integer divide fault", /* 18 T_DIVIDE */ 157 "non-maskable interrupt trap", /* 19 T_NMI */ 158 "overflow trap", /* 20 T_OFLOW */ 159 "FPU bounds check fault", /* 21 T_BOUND */ 160 "FPU device not available", /* 22 T_DNA */ 161 "double fault", /* 23 T_DOUBLEFLT */ 162 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 163 "invalid TSS fault", /* 25 T_TSSFLT */ 164 "segment not present fault", /* 26 T_SEGNPFLT */ 165 "stack fault", /* 27 T_STKFLT */ 166 "machine check trap", /* 28 T_MCHK */ 167 "SIMD floating-point exception", /* 29 T_XMMFLT */ 168 "reserved (unknown) fault", /* 30 T_RESERVED */ 169 }; 170 171 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 172 extern int has_f00f_bug; 173 #endif 174 175 #ifdef KDB 176 static int kdb_on_nmi = 1; 177 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 178 &kdb_on_nmi, 0, "Go to KDB on NMI"); 179 #endif 180 static int panic_on_nmi = 1; 181 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 182 &panic_on_nmi, 0, "Panic on NMI"); 183 static int prot_fault_translation = 0; 184 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 185 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 186 187 /* 188 * Exception, fault, and trap interface to the FreeBSD kernel. 189 * This common code is called from assembly language IDT gate entry 190 * routines that prepare a suitable stack frame, and restore this 191 * frame after the exception has been processed. 192 */ 193 194 void 195 trap(struct trapframe *frame) 196 { 197 struct thread *td = curthread; 198 struct proc *p = td->td_proc; 199 int i = 0, ucode = 0, code; 200 u_int type; 201 register_t addr = 0; 202 vm_offset_t eva; 203 ksiginfo_t ksi; 204 #ifdef POWERFAIL_NMI 205 static int lastalert = 0; 206 #endif 207 208 PCPU_INC(cnt.v_trap); 209 type = frame->tf_trapno; 210 211 #ifdef SMP 212 /* Handler for NMI IPIs used for stopping CPUs. */ 213 if (type == T_NMI) { 214 if (ipi_nmi_handler() == 0) 215 goto out; 216 } 217 #endif /* SMP */ 218 219 #ifdef KDB 220 if (kdb_active) { 221 kdb_reenter(); 222 goto out; 223 } 224 #endif 225 226 if (type == T_RESERVED) { 227 trap_fatal(frame, 0); 228 goto out; 229 } 230 231 #ifdef HWPMC_HOOKS 232 /* 233 * CPU PMCs interrupt using an NMI so we check for that first. 234 * If the HWPMC module is active, 'pmc_hook' will point to 235 * the function to be called. A return value of '1' from the 236 * hook means that the NMI was handled by it and that we can 237 * return immediately. 238 */ 239 if (type == T_NMI && pmc_intr && 240 (*pmc_intr)(PCPU_GET(cpuid), frame)) 241 goto out; 242 #endif 243 244 if (type == T_MCHK) { 245 if (!mca_intr()) 246 trap_fatal(frame, 0); 247 goto out; 248 } 249 250 #ifdef KDTRACE_HOOKS 251 /* 252 * A trap can occur while DTrace executes a probe. Before 253 * executing the probe, DTrace blocks re-scheduling and sets 254 * a flag in it's per-cpu flags to indicate that it doesn't 255 * want to fault. On returning from the the probe, the no-fault 256 * flag is cleared and finally re-scheduling is enabled. 257 * 258 * If the DTrace kernel module has registered a trap handler, 259 * call it and if it returns non-zero, assume that it has 260 * handled the trap and modified the trap frame so that this 261 * function can return normally. 262 */ 263 if ((type == T_PROTFLT || type == T_PAGEFLT) && 264 dtrace_trap_func != NULL) 265 if ((*dtrace_trap_func)(frame, type)) 266 goto out; 267 #endif 268 269 if ((frame->tf_eflags & PSL_I) == 0) { 270 /* 271 * Buggy application or kernel code has disabled 272 * interrupts and then trapped. Enabling interrupts 273 * now is wrong, but it is better than running with 274 * interrupts disabled until they are accidentally 275 * enabled later. 276 */ 277 if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM)) 278 uprintf( 279 "pid %ld (%s): trap %d with interrupts disabled\n", 280 (long)curproc->p_pid, curthread->td_name, type); 281 else if (type != T_BPTFLT && type != T_TRCTRAP && 282 frame->tf_eip != (int)cpu_switch_load_gs) { 283 /* 284 * XXX not quite right, since this may be for a 285 * multiple fault in user mode. 286 */ 287 printf("kernel trap %d with interrupts disabled\n", 288 type); 289 /* 290 * Page faults need interrupts disabled until later, 291 * and we shouldn't enable interrupts while holding 292 * a spin lock or if servicing an NMI. 293 */ 294 if (type != T_NMI && type != T_PAGEFLT && 295 td->td_md.md_spinlock_count == 0) 296 enable_intr(); 297 } 298 } 299 eva = 0; 300 code = frame->tf_err; 301 if (type == T_PAGEFLT) { 302 /* 303 * For some Cyrix CPUs, %cr2 is clobbered by 304 * interrupts. This problem is worked around by using 305 * an interrupt gate for the pagefault handler. We 306 * are finally ready to read %cr2 and then must 307 * reenable interrupts. 308 * 309 * If we get a page fault while in a critical section, then 310 * it is most likely a fatal kernel page fault. The kernel 311 * is already going to panic trying to get a sleep lock to 312 * do the VM lookup, so just consider it a fatal trap so the 313 * kernel can print out a useful trap message and even get 314 * to the debugger. 315 * 316 * If we get a page fault while holding a non-sleepable 317 * lock, then it is most likely a fatal kernel page fault. 318 * If WITNESS is enabled, then it's going to whine about 319 * bogus LORs with various VM locks, so just skip to the 320 * fatal trap handling directly. 321 */ 322 eva = rcr2(); 323 if (td->td_critnest != 0 || 324 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 325 "Kernel page fault") != 0) 326 trap_fatal(frame, eva); 327 else 328 enable_intr(); 329 } 330 331 if ((ISPL(frame->tf_cs) == SEL_UPL) || 332 ((frame->tf_eflags & PSL_VM) && 333 !(PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL))) { 334 /* user trap */ 335 336 td->td_pticks = 0; 337 td->td_frame = frame; 338 addr = frame->tf_eip; 339 if (td->td_ucred != p->p_ucred) 340 cred_update_thread(td); 341 342 switch (type) { 343 case T_PRIVINFLT: /* privileged instruction fault */ 344 i = SIGILL; 345 ucode = ILL_PRVOPC; 346 break; 347 348 case T_BPTFLT: /* bpt instruction fault */ 349 case T_TRCTRAP: /* trace trap */ 350 enable_intr(); 351 frame->tf_eflags &= ~PSL_T; 352 i = SIGTRAP; 353 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 354 break; 355 356 case T_ARITHTRAP: /* arithmetic trap */ 357 #ifdef DEV_NPX 358 ucode = npxtrap(); 359 if (ucode == -1) 360 goto userout; 361 #else 362 ucode = 0; 363 #endif 364 i = SIGFPE; 365 break; 366 367 /* 368 * The following two traps can happen in 369 * vm86 mode, and, if so, we want to handle 370 * them specially. 371 */ 372 case T_PROTFLT: /* general protection fault */ 373 case T_STKFLT: /* stack fault */ 374 if (frame->tf_eflags & PSL_VM) { 375 i = vm86_emulate((struct vm86frame *)frame); 376 if (i == 0) 377 goto user; 378 break; 379 } 380 i = SIGBUS; 381 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; 382 break; 383 case T_SEGNPFLT: /* segment not present fault */ 384 i = SIGBUS; 385 ucode = BUS_ADRERR; 386 break; 387 case T_TSSFLT: /* invalid TSS fault */ 388 i = SIGBUS; 389 ucode = BUS_OBJERR; 390 break; 391 case T_DOUBLEFLT: /* double fault */ 392 default: 393 i = SIGBUS; 394 ucode = BUS_OBJERR; 395 break; 396 397 case T_PAGEFLT: /* page fault */ 398 399 i = trap_pfault(frame, TRUE, eva); 400 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 401 if (i == -2) { 402 /* 403 * The f00f hack workaround has triggered, so 404 * treat the fault as an illegal instruction 405 * (T_PRIVINFLT) instead of a page fault. 406 */ 407 type = frame->tf_trapno = T_PRIVINFLT; 408 409 /* Proceed as in that case. */ 410 ucode = ILL_PRVOPC; 411 i = SIGILL; 412 break; 413 } 414 #endif 415 if (i == -1) 416 goto userout; 417 if (i == 0) 418 goto user; 419 420 if (i == SIGSEGV) 421 ucode = SEGV_MAPERR; 422 else { 423 if (prot_fault_translation == 0) { 424 /* 425 * Autodetect. 426 * This check also covers the images 427 * without the ABI-tag ELF note. 428 */ 429 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 430 && p->p_osrel >= P_OSREL_SIGSEGV) { 431 i = SIGSEGV; 432 ucode = SEGV_ACCERR; 433 } else { 434 i = SIGBUS; 435 ucode = BUS_PAGE_FAULT; 436 } 437 } else if (prot_fault_translation == 1) { 438 /* 439 * Always compat mode. 440 */ 441 i = SIGBUS; 442 ucode = BUS_PAGE_FAULT; 443 } else { 444 /* 445 * Always SIGSEGV mode. 446 */ 447 i = SIGSEGV; 448 ucode = SEGV_ACCERR; 449 } 450 } 451 addr = eva; 452 break; 453 454 case T_DIVIDE: /* integer divide fault */ 455 ucode = FPE_INTDIV; 456 i = SIGFPE; 457 break; 458 459 #ifdef DEV_ISA 460 case T_NMI: 461 #ifdef POWERFAIL_NMI 462 #ifndef TIMER_FREQ 463 # define TIMER_FREQ 1193182 464 #endif 465 if (time_second - lastalert > 10) { 466 log(LOG_WARNING, "NMI: power fail\n"); 467 sysbeep(880, hz); 468 lastalert = time_second; 469 } 470 goto userout; 471 #else /* !POWERFAIL_NMI */ 472 /* machine/parity/power fail/"kitchen sink" faults */ 473 if (isa_nmi(code) == 0) { 474 #ifdef KDB 475 /* 476 * NMI can be hooked up to a pushbutton 477 * for debugging. 478 */ 479 if (kdb_on_nmi) { 480 printf ("NMI ... going to debugger\n"); 481 kdb_trap(type, 0, frame); 482 } 483 #endif /* KDB */ 484 goto userout; 485 } else if (panic_on_nmi) 486 panic("NMI indicates hardware failure"); 487 break; 488 #endif /* POWERFAIL_NMI */ 489 #endif /* DEV_ISA */ 490 491 case T_OFLOW: /* integer overflow fault */ 492 ucode = FPE_INTOVF; 493 i = SIGFPE; 494 break; 495 496 case T_BOUND: /* bounds check fault */ 497 ucode = FPE_FLTSUB; 498 i = SIGFPE; 499 break; 500 501 case T_DNA: 502 #ifdef DEV_NPX 503 KASSERT(PCB_USER_FPU(td->td_pcb), 504 ("kernel FPU ctx has leaked")); 505 /* transparent fault (due to context switch "late") */ 506 if (npxdna()) 507 goto userout; 508 #endif 509 uprintf("pid %d killed due to lack of floating point\n", 510 p->p_pid); 511 i = SIGKILL; 512 ucode = 0; 513 break; 514 515 case T_FPOPFLT: /* FPU operand fetch fault */ 516 ucode = ILL_COPROC; 517 i = SIGILL; 518 break; 519 520 case T_XMMFLT: /* SIMD floating-point exception */ 521 ucode = 0; /* XXX */ 522 i = SIGFPE; 523 break; 524 } 525 } else { 526 /* kernel trap */ 527 528 KASSERT(cold || td->td_ucred != NULL, 529 ("kernel trap doesn't have ucred")); 530 switch (type) { 531 case T_PAGEFLT: /* page fault */ 532 (void) trap_pfault(frame, FALSE, eva); 533 goto out; 534 535 case T_DNA: 536 #ifdef DEV_NPX 537 KASSERT(!PCB_USER_FPU(td->td_pcb), 538 ("Unregistered use of FPU in kernel")); 539 if (npxdna()) 540 goto out; 541 #endif 542 break; 543 544 case T_ARITHTRAP: /* arithmetic trap */ 545 case T_XMMFLT: /* SIMD floating-point exception */ 546 case T_FPOPFLT: /* FPU operand fetch fault */ 547 /* 548 * XXXKIB for now disable any FPU traps in kernel 549 * handler registration seems to be overkill 550 */ 551 trap_fatal(frame, 0); 552 goto out; 553 554 /* 555 * The following two traps can happen in 556 * vm86 mode, and, if so, we want to handle 557 * them specially. 558 */ 559 case T_PROTFLT: /* general protection fault */ 560 case T_STKFLT: /* stack fault */ 561 if (frame->tf_eflags & PSL_VM) { 562 i = vm86_emulate((struct vm86frame *)frame); 563 if (i != 0) 564 /* 565 * returns to original process 566 */ 567 vm86_trap((struct vm86frame *)frame); 568 goto out; 569 } 570 if (type == T_STKFLT) 571 break; 572 573 /* FALL THROUGH */ 574 575 case T_SEGNPFLT: /* segment not present fault */ 576 if (PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL) 577 break; 578 579 /* 580 * Invalid %fs's and %gs's can be created using 581 * procfs or PT_SETREGS or by invalidating the 582 * underlying LDT entry. This causes a fault 583 * in kernel mode when the kernel attempts to 584 * switch contexts. Lose the bad context 585 * (XXX) so that we can continue, and generate 586 * a signal. 587 */ 588 if (frame->tf_eip == (int)cpu_switch_load_gs) { 589 PCPU_GET(curpcb)->pcb_gs = 0; 590 #if 0 591 PROC_LOCK(p); 592 psignal(p, SIGBUS); 593 PROC_UNLOCK(p); 594 #endif 595 goto out; 596 } 597 598 if (td->td_intr_nesting_level != 0) 599 break; 600 601 /* 602 * Invalid segment selectors and out of bounds 603 * %eip's and %esp's can be set up in user mode. 604 * This causes a fault in kernel mode when the 605 * kernel tries to return to user mode. We want 606 * to get this fault so that we can fix the 607 * problem here and not have to check all the 608 * selectors and pointers when the user changes 609 * them. 610 */ 611 if (frame->tf_eip == (int)doreti_iret) { 612 frame->tf_eip = (int)doreti_iret_fault; 613 goto out; 614 } 615 if (frame->tf_eip == (int)doreti_popl_ds) { 616 frame->tf_eip = (int)doreti_popl_ds_fault; 617 goto out; 618 } 619 if (frame->tf_eip == (int)doreti_popl_es) { 620 frame->tf_eip = (int)doreti_popl_es_fault; 621 goto out; 622 } 623 if (frame->tf_eip == (int)doreti_popl_fs) { 624 frame->tf_eip = (int)doreti_popl_fs_fault; 625 goto out; 626 } 627 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 628 frame->tf_eip = 629 (int)PCPU_GET(curpcb)->pcb_onfault; 630 goto out; 631 } 632 break; 633 634 case T_TSSFLT: 635 /* 636 * PSL_NT can be set in user mode and isn't cleared 637 * automatically when the kernel is entered. This 638 * causes a TSS fault when the kernel attempts to 639 * `iret' because the TSS link is uninitialized. We 640 * want to get this fault so that we can fix the 641 * problem here and not every time the kernel is 642 * entered. 643 */ 644 if (frame->tf_eflags & PSL_NT) { 645 frame->tf_eflags &= ~PSL_NT; 646 goto out; 647 } 648 break; 649 650 case T_TRCTRAP: /* trace trap */ 651 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) { 652 /* 653 * We've just entered system mode via the 654 * syscall lcall. Continue single stepping 655 * silently until the syscall handler has 656 * saved the flags. 657 */ 658 goto out; 659 } 660 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 661 /* 662 * The syscall handler has now saved the 663 * flags. Stop single stepping it. 664 */ 665 frame->tf_eflags &= ~PSL_T; 666 goto out; 667 } 668 /* 669 * Ignore debug register trace traps due to 670 * accesses in the user's address space, which 671 * can happen under several conditions such as 672 * if a user sets a watchpoint on a buffer and 673 * then passes that buffer to a system call. 674 * We still want to get TRCTRAPS for addresses 675 * in kernel space because that is useful when 676 * debugging the kernel. 677 */ 678 if (user_dbreg_trap() && 679 !(PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL)) { 680 /* 681 * Reset breakpoint bits because the 682 * processor doesn't 683 */ 684 load_dr6(rdr6() & 0xfffffff0); 685 goto out; 686 } 687 /* 688 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 689 */ 690 case T_BPTFLT: 691 /* 692 * If KDB is enabled, let it handle the debugger trap. 693 * Otherwise, debugger traps "can't happen". 694 */ 695 #ifdef KDB 696 if (kdb_trap(type, 0, frame)) 697 goto out; 698 #endif 699 break; 700 701 #ifdef DEV_ISA 702 case T_NMI: 703 #ifdef POWERFAIL_NMI 704 if (time_second - lastalert > 10) { 705 log(LOG_WARNING, "NMI: power fail\n"); 706 sysbeep(880, hz); 707 lastalert = time_second; 708 } 709 goto out; 710 #else /* !POWERFAIL_NMI */ 711 /* machine/parity/power fail/"kitchen sink" faults */ 712 if (isa_nmi(code) == 0) { 713 #ifdef KDB 714 /* 715 * NMI can be hooked up to a pushbutton 716 * for debugging. 717 */ 718 if (kdb_on_nmi) { 719 printf ("NMI ... going to debugger\n"); 720 kdb_trap(type, 0, frame); 721 } 722 #endif /* KDB */ 723 goto out; 724 } else if (panic_on_nmi == 0) 725 goto out; 726 /* FALLTHROUGH */ 727 #endif /* POWERFAIL_NMI */ 728 #endif /* DEV_ISA */ 729 } 730 731 trap_fatal(frame, eva); 732 goto out; 733 } 734 735 /* Translate fault for emulators (e.g. Linux) */ 736 if (*p->p_sysent->sv_transtrap) 737 i = (*p->p_sysent->sv_transtrap)(i, type); 738 739 ksiginfo_init_trap(&ksi); 740 ksi.ksi_signo = i; 741 ksi.ksi_code = ucode; 742 ksi.ksi_addr = (void *)addr; 743 ksi.ksi_trapno = type; 744 trapsignal(td, &ksi); 745 746 #ifdef DEBUG 747 if (type <= MAX_TRAP_MSG) { 748 uprintf("fatal process exception: %s", 749 trap_msg[type]); 750 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 751 uprintf(", fault VA = 0x%lx", (u_long)eva); 752 uprintf("\n"); 753 } 754 #endif 755 756 user: 757 userret(td, frame); 758 mtx_assert(&Giant, MA_NOTOWNED); 759 KASSERT(PCB_USER_FPU(td->td_pcb), 760 ("Return from trap with kernel FPU ctx leaked")); 761 userout: 762 out: 763 return; 764 } 765 766 static int 767 trap_pfault(frame, usermode, eva) 768 struct trapframe *frame; 769 int usermode; 770 vm_offset_t eva; 771 { 772 vm_offset_t va; 773 struct vmspace *vm = NULL; 774 vm_map_t map; 775 int rv = 0; 776 vm_prot_t ftype; 777 struct thread *td = curthread; 778 struct proc *p = td->td_proc; 779 780 va = trunc_page(eva); 781 if (va >= KERNBASE) { 782 /* 783 * Don't allow user-mode faults in kernel address space. 784 * An exception: if the faulting address is the invalid 785 * instruction entry in the IDT, then the Intel Pentium 786 * F00F bug workaround was triggered, and we need to 787 * treat it is as an illegal instruction, and not a page 788 * fault. 789 */ 790 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 791 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) 792 return -2; 793 #endif 794 if (usermode) 795 goto nogo; 796 797 map = kernel_map; 798 } else { 799 /* 800 * This is a fault on non-kernel virtual memory. 801 * vm is initialized above to NULL. If curproc is NULL 802 * or curproc->p_vmspace is NULL the fault is fatal. 803 */ 804 if (p != NULL) 805 vm = p->p_vmspace; 806 807 if (vm == NULL) 808 goto nogo; 809 810 map = &vm->vm_map; 811 } 812 813 /* 814 * PGEX_I is defined only if the execute disable bit capability is 815 * supported and enabled. 816 */ 817 if (frame->tf_err & PGEX_W) 818 ftype = VM_PROT_WRITE; 819 #ifdef PAE 820 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 821 ftype = VM_PROT_EXECUTE; 822 #endif 823 else 824 ftype = VM_PROT_READ; 825 826 if (map != kernel_map) { 827 /* 828 * Keep swapout from messing with us during this 829 * critical time. 830 */ 831 PROC_LOCK(p); 832 ++p->p_lock; 833 PROC_UNLOCK(p); 834 835 /* Fault in the user page: */ 836 rv = vm_fault(map, va, ftype, 837 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 838 : VM_FAULT_NORMAL); 839 840 PROC_LOCK(p); 841 --p->p_lock; 842 PROC_UNLOCK(p); 843 } else { 844 /* 845 * Don't have to worry about process locking or stacks in the 846 * kernel. 847 */ 848 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 849 } 850 if (rv == KERN_SUCCESS) 851 return (0); 852 nogo: 853 if (!usermode) { 854 if (td->td_intr_nesting_level == 0 && 855 PCPU_GET(curpcb)->pcb_onfault != NULL) { 856 frame->tf_eip = (int)PCPU_GET(curpcb)->pcb_onfault; 857 return (0); 858 } 859 trap_fatal(frame, eva); 860 return (-1); 861 } 862 863 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 864 } 865 866 static void 867 trap_fatal(frame, eva) 868 struct trapframe *frame; 869 vm_offset_t eva; 870 { 871 int code, ss, esp; 872 u_int type; 873 struct soft_segment_descriptor softseg; 874 char *msg; 875 876 code = frame->tf_err; 877 type = frame->tf_trapno; 878 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 879 880 if (type <= MAX_TRAP_MSG) 881 msg = trap_msg[type]; 882 else 883 msg = "UNKNOWN"; 884 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 885 frame->tf_eflags & PSL_VM ? "vm86" : 886 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 887 #ifdef SMP 888 /* two separate prints in case of a trap on an unmapped page */ 889 printf("cpuid = %d; ", PCPU_GET(cpuid)); 890 printf("apic id = %02x\n", PCPU_GET(apic_id)); 891 #endif 892 if (type == T_PAGEFLT) { 893 printf("fault virtual address = 0x%x\n", eva); 894 printf("fault code = %s %s, %s\n", 895 code & PGEX_U ? "user" : "supervisor", 896 code & PGEX_W ? "write" : "read", 897 code & PGEX_P ? "protection violation" : "page not present"); 898 } 899 printf("instruction pointer = 0x%x:0x%x\n", 900 frame->tf_cs & 0xffff, frame->tf_eip); 901 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 902 ss = frame->tf_ss & 0xffff; 903 esp = frame->tf_esp; 904 } else { 905 ss = GSEL(GDATA_SEL, SEL_KPL); 906 esp = (int)&frame->tf_esp; 907 } 908 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 909 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 910 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 911 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 912 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 913 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 914 softseg.ssd_gran); 915 printf("processor eflags = "); 916 if (frame->tf_eflags & PSL_T) 917 printf("trace trap, "); 918 if (frame->tf_eflags & PSL_I) 919 printf("interrupt enabled, "); 920 if (frame->tf_eflags & PSL_NT) 921 printf("nested task, "); 922 if (frame->tf_eflags & PSL_RF) 923 printf("resume, "); 924 if (frame->tf_eflags & PSL_VM) 925 printf("vm86, "); 926 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 927 printf("current process = "); 928 if (curproc) { 929 printf("%lu (%s)\n", (u_long)curproc->p_pid, curthread->td_name); 930 } else { 931 printf("Idle\n"); 932 } 933 934 #ifdef KDB 935 if (debugger_on_panic || kdb_active) { 936 frame->tf_err = eva; /* smuggle fault address to ddb */ 937 if (kdb_trap(type, 0, frame)) { 938 frame->tf_err = code; /* restore error code */ 939 return; 940 } 941 frame->tf_err = code; /* restore error code */ 942 } 943 #endif 944 printf("trap number = %d\n", type); 945 if (type <= MAX_TRAP_MSG) 946 panic("%s", trap_msg[type]); 947 else 948 panic("unknown/reserved trap"); 949 } 950 951 /* 952 * Double fault handler. Called when a fault occurs while writing 953 * a frame for a trap/exception onto the stack. This usually occurs 954 * when the stack overflows (such is the case with infinite recursion, 955 * for example). 956 * 957 * XXX Note that the current PTD gets replaced by IdlePTD when the 958 * task switch occurs. This means that the stack that was active at 959 * the time of the double fault is not available at <kstack> unless 960 * the machine was idle when the double fault occurred. The downside 961 * of this is that "trace <ebp>" in ddb won't work. 962 */ 963 void 964 dblfault_handler() 965 { 966 #ifdef KDTRACE_HOOKS 967 if (dtrace_doubletrap_func != NULL) 968 (*dtrace_doubletrap_func)(); 969 #endif 970 printf("\nFatal double fault:\n"); 971 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 972 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 973 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 974 #ifdef SMP 975 /* two separate prints in case of a trap on an unmapped page */ 976 printf("cpuid = %d; ", PCPU_GET(cpuid)); 977 printf("apic id = %02x\n", PCPU_GET(apic_id)); 978 #endif 979 panic("double fault"); 980 } 981 982 int 983 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 984 { 985 struct proc *p; 986 struct trapframe *frame; 987 caddr_t params; 988 int error; 989 990 p = td->td_proc; 991 frame = td->td_frame; 992 993 params = (caddr_t)frame->tf_esp + sizeof(int); 994 sa->code = frame->tf_eax; 995 996 /* 997 * Need to check if this is a 32 bit or 64 bit syscall. 998 */ 999 if (sa->code == SYS_syscall) { 1000 /* 1001 * Code is first argument, followed by actual args. 1002 */ 1003 sa->code = fuword(params); 1004 params += sizeof(int); 1005 } else if (sa->code == SYS___syscall) { 1006 /* 1007 * Like syscall, but code is a quad, so as to maintain 1008 * quad alignment for the rest of the arguments. 1009 */ 1010 sa->code = fuword(params); 1011 params += sizeof(quad_t); 1012 } 1013 1014 if (p->p_sysent->sv_mask) 1015 sa->code &= p->p_sysent->sv_mask; 1016 if (sa->code >= p->p_sysent->sv_size) 1017 sa->callp = &p->p_sysent->sv_table[0]; 1018 else 1019 sa->callp = &p->p_sysent->sv_table[sa->code]; 1020 sa->narg = sa->callp->sy_narg; 1021 1022 if (params != NULL && sa->narg != 0) 1023 error = copyin(params, (caddr_t)sa->args, 1024 (u_int)(sa->narg * sizeof(int))); 1025 else 1026 error = 0; 1027 1028 if (error == 0) { 1029 td->td_retval[0] = 0; 1030 td->td_retval[1] = frame->tf_edx; 1031 } 1032 1033 return (error); 1034 } 1035 1036 /* 1037 * syscall - system call request C handler 1038 * 1039 * A system call is essentially treated as a trap. 1040 */ 1041 void 1042 syscall(struct trapframe *frame) 1043 { 1044 struct thread *td; 1045 struct syscall_args sa; 1046 register_t orig_tf_eflags; 1047 int error; 1048 ksiginfo_t ksi; 1049 1050 #ifdef DIAGNOSTIC 1051 if (ISPL(frame->tf_cs) != SEL_UPL) { 1052 panic("syscall"); 1053 /* NOT REACHED */ 1054 } 1055 #endif 1056 orig_tf_eflags = frame->tf_eflags; 1057 1058 td = curthread; 1059 td->td_frame = frame; 1060 1061 error = syscallenter(td, &sa); 1062 1063 /* 1064 * Traced syscall. 1065 */ 1066 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { 1067 frame->tf_eflags &= ~PSL_T; 1068 ksiginfo_init_trap(&ksi); 1069 ksi.ksi_signo = SIGTRAP; 1070 ksi.ksi_code = TRAP_TRACE; 1071 ksi.ksi_addr = (void *)frame->tf_eip; 1072 trapsignal(td, &ksi); 1073 } 1074 1075 KASSERT(PCB_USER_FPU(td->td_pcb), 1076 ("System call %s returning with kernel FPU ctx leaked", 1077 syscallname(td->td_proc, sa.code))); 1078 KASSERT(td->td_pcb->pcb_save == &td->td_pcb->pcb_user_save, 1079 ("System call %s returning with mangled pcb_save", 1080 syscallname(td->td_proc, sa.code))); 1081 1082 syscallret(td, error, &sa); 1083 }
Cache object: bf775726d99644bbdddf161f7747e74e
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