Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
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("$FreeBSD$"); 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_ktrace.h" 53 #include "opt_npx.h" 54 #include "opt_trap.h" 55 56 #include <sys/param.h> 57 #include <sys/bus.h> 58 #include <sys/systm.h> 59 #include <sys/proc.h> 60 #include <sys/pioctl.h> 61 #include <sys/ptrace.h> 62 #include <sys/kdb.h> 63 #include <sys/kernel.h> 64 #include <sys/ktr.h> 65 #include <sys/lock.h> 66 #include <sys/mutex.h> 67 #include <sys/resourcevar.h> 68 #include <sys/signalvar.h> 69 #include <sys/syscall.h> 70 #include <sys/sysctl.h> 71 #include <sys/sysent.h> 72 #include <sys/uio.h> 73 #include <sys/vmmeter.h> 74 #ifdef KTRACE 75 #include <sys/ktrace.h> 76 #endif 77 #ifdef HWPMC_HOOKS 78 #include <sys/pmckern.h> 79 #endif 80 #include <security/audit/audit.h> 81 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <vm/pmap.h> 85 #include <vm/vm_kern.h> 86 #include <vm/vm_map.h> 87 #include <vm/vm_page.h> 88 #include <vm/vm_extern.h> 89 90 #include <machine/cpu.h> 91 #include <machine/intr_machdep.h> 92 #include <machine/md_var.h> 93 #include <machine/pcb.h> 94 #ifdef SMP 95 #include <machine/smp.h> 96 #endif 97 #include <machine/tss.h> 98 #include <machine/vm86.h> 99 100 #ifdef POWERFAIL_NMI 101 #include <sys/syslog.h> 102 #include <machine/clock.h> 103 #endif 104 105 extern void trap(struct trapframe *frame); 106 extern void syscall(struct trapframe *frame); 107 108 static int trap_pfault(struct trapframe *, int, vm_offset_t); 109 static void trap_fatal(struct trapframe *, vm_offset_t); 110 void dblfault_handler(void); 111 112 extern inthand_t IDTVEC(lcall_syscall); 113 114 #define MAX_TRAP_MSG 30 115 static char *trap_msg[] = { 116 "", /* 0 unused */ 117 "privileged instruction fault", /* 1 T_PRIVINFLT */ 118 "", /* 2 unused */ 119 "breakpoint instruction fault", /* 3 T_BPTFLT */ 120 "", /* 4 unused */ 121 "", /* 5 unused */ 122 "arithmetic trap", /* 6 T_ARITHTRAP */ 123 "", /* 7 unused */ 124 "", /* 8 unused */ 125 "general protection fault", /* 9 T_PROTFLT */ 126 "trace trap", /* 10 T_TRCTRAP */ 127 "", /* 11 unused */ 128 "page fault", /* 12 T_PAGEFLT */ 129 "", /* 13 unused */ 130 "alignment fault", /* 14 T_ALIGNFLT */ 131 "", /* 15 unused */ 132 "", /* 16 unused */ 133 "", /* 17 unused */ 134 "integer divide fault", /* 18 T_DIVIDE */ 135 "non-maskable interrupt trap", /* 19 T_NMI */ 136 "overflow trap", /* 20 T_OFLOW */ 137 "FPU bounds check fault", /* 21 T_BOUND */ 138 "FPU device not available", /* 22 T_DNA */ 139 "double fault", /* 23 T_DOUBLEFLT */ 140 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 141 "invalid TSS fault", /* 25 T_TSSFLT */ 142 "segment not present fault", /* 26 T_SEGNPFLT */ 143 "stack fault", /* 27 T_STKFLT */ 144 "machine check trap", /* 28 T_MCHK */ 145 "SIMD floating-point exception", /* 29 T_XMMFLT */ 146 "reserved (unknown) fault", /* 30 T_RESERVED */ 147 }; 148 149 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 150 extern int has_f00f_bug; 151 #endif 152 153 #ifdef KDB 154 static int kdb_on_nmi = 1; 155 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 156 &kdb_on_nmi, 0, "Go to KDB on NMI"); 157 #endif 158 static int panic_on_nmi = 1; 159 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 160 &panic_on_nmi, 0, "Panic on NMI"); 161 static int prot_fault_translation = 0; 162 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 163 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 164 165 extern char *syscallnames[]; 166 167 /* 168 * Exception, fault, and trap interface to the FreeBSD kernel. 169 * This common code is called from assembly language IDT gate entry 170 * routines that prepare a suitable stack frame, and restore this 171 * frame after the exception has been processed. 172 */ 173 174 void 175 trap(struct trapframe *frame) 176 { 177 struct thread *td = curthread; 178 struct proc *p = td->td_proc; 179 int i = 0, ucode = 0, code; 180 u_int type; 181 register_t addr = 0; 182 vm_offset_t eva; 183 ksiginfo_t ksi; 184 #ifdef POWERFAIL_NMI 185 static int lastalert = 0; 186 #endif 187 188 PCPU_INC(cnt.v_trap); 189 type = frame->tf_trapno; 190 191 #ifdef SMP 192 #ifdef STOP_NMI 193 /* Handler for NMI IPIs used for stopping CPUs. */ 194 if (type == T_NMI) { 195 if (ipi_nmi_handler() == 0) 196 goto out; 197 } 198 #endif /* STOP_NMI */ 199 #endif /* SMP */ 200 201 #ifdef KDB 202 if (kdb_active) { 203 kdb_reenter(); 204 goto out; 205 } 206 #endif 207 208 #ifdef HWPMC_HOOKS 209 /* 210 * CPU PMCs interrupt using an NMI so we check for that first. 211 * If the HWPMC module is active, 'pmc_hook' will point to 212 * the function to be called. A return value of '1' from the 213 * hook means that the NMI was handled by it and that we can 214 * return immediately. 215 */ 216 if (type == T_NMI && pmc_intr && 217 (*pmc_intr)(PCPU_GET(cpuid), (uintptr_t) frame->tf_eip, 218 TRAPF_USERMODE(frame))) 219 goto out; 220 #endif 221 222 if ((frame->tf_eflags & PSL_I) == 0) { 223 /* 224 * Buggy application or kernel code has disabled 225 * interrupts and then trapped. Enabling interrupts 226 * now is wrong, but it is better than running with 227 * interrupts disabled until they are accidentally 228 * enabled later. 229 */ 230 if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM)) 231 printf( 232 "pid %ld (%s): trap %d with interrupts disabled\n", 233 (long)curproc->p_pid, curproc->p_comm, type); 234 else if (type != T_BPTFLT && type != T_TRCTRAP && 235 frame->tf_eip != (int)cpu_switch_load_gs) { 236 /* 237 * XXX not quite right, since this may be for a 238 * multiple fault in user mode. 239 */ 240 printf("kernel trap %d with interrupts disabled\n", 241 type); 242 /* 243 * Page faults need interrupts disabled until later, 244 * and we shouldn't enable interrupts while holding 245 * a spin lock or if servicing an NMI. 246 */ 247 if (type != T_NMI && type != T_PAGEFLT && 248 td->td_md.md_spinlock_count == 0) 249 enable_intr(); 250 } 251 } 252 253 eva = 0; 254 code = frame->tf_err; 255 if (type == T_PAGEFLT) { 256 /* 257 * For some Cyrix CPUs, %cr2 is clobbered by 258 * interrupts. This problem is worked around by using 259 * an interrupt gate for the pagefault handler. We 260 * are finally ready to read %cr2 and then must 261 * reenable interrupts. 262 * 263 * If we get a page fault while in a critical section, then 264 * it is most likely a fatal kernel page fault. The kernel 265 * is already going to panic trying to get a sleep lock to 266 * do the VM lookup, so just consider it a fatal trap so the 267 * kernel can print out a useful trap message and even get 268 * to the debugger. 269 * 270 * If we get a page fault while holding a non-sleepable 271 * lock, then it is most likely a fatal kernel page fault. 272 * If WITNESS is enabled, then it's going to whine about 273 * bogus LORs with various VM locks, so just skip to the 274 * fatal trap handling directly. 275 */ 276 eva = rcr2(); 277 if (td->td_critnest != 0 || 278 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 279 "Kernel page fault") != 0) 280 trap_fatal(frame, eva); 281 else 282 enable_intr(); 283 } 284 285 if ((ISPL(frame->tf_cs) == SEL_UPL) || 286 ((frame->tf_eflags & PSL_VM) && 287 !(PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL))) { 288 /* user trap */ 289 290 td->td_pticks = 0; 291 td->td_frame = frame; 292 addr = frame->tf_eip; 293 if (td->td_ucred != p->p_ucred) 294 cred_update_thread(td); 295 296 switch (type) { 297 case T_PRIVINFLT: /* privileged instruction fault */ 298 i = SIGILL; 299 ucode = ILL_PRVOPC; 300 break; 301 302 case T_BPTFLT: /* bpt instruction fault */ 303 case T_TRCTRAP: /* trace trap */ 304 enable_intr(); 305 frame->tf_eflags &= ~PSL_T; 306 i = SIGTRAP; 307 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 308 break; 309 310 case T_ARITHTRAP: /* arithmetic trap */ 311 #ifdef DEV_NPX 312 ucode = npxtrap(); 313 if (ucode == -1) 314 goto userout; 315 #else 316 ucode = 0; 317 #endif 318 i = SIGFPE; 319 break; 320 321 /* 322 * The following two traps can happen in 323 * vm86 mode, and, if so, we want to handle 324 * them specially. 325 */ 326 case T_PROTFLT: /* general protection fault */ 327 case T_STKFLT: /* stack fault */ 328 if (frame->tf_eflags & PSL_VM) { 329 i = vm86_emulate((struct vm86frame *)frame); 330 if (i == 0) 331 goto user; 332 break; 333 } 334 i = SIGBUS; 335 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; 336 break; 337 case T_SEGNPFLT: /* segment not present fault */ 338 i = SIGBUS; 339 ucode = BUS_ADRERR; 340 break; 341 case T_TSSFLT: /* invalid TSS fault */ 342 i = SIGBUS; 343 ucode = BUS_OBJERR; 344 break; 345 case T_DOUBLEFLT: /* double fault */ 346 default: 347 i = SIGBUS; 348 ucode = BUS_OBJERR; 349 break; 350 351 case T_PAGEFLT: /* page fault */ 352 #ifdef KSE 353 if (td->td_pflags & TDP_SA) 354 thread_user_enter(td); 355 #endif 356 357 i = trap_pfault(frame, TRUE, eva); 358 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 359 if (i == -2) { 360 /* 361 * The f00f hack workaround has triggered, so 362 * treat the fault as an illegal instruction 363 * (T_PRIVINFLT) instead of a page fault. 364 */ 365 type = frame->tf_trapno = T_PRIVINFLT; 366 367 /* Proceed as in that case. */ 368 ucode = ILL_PRVOPC; 369 i = SIGILL; 370 break; 371 } 372 #endif 373 if (i == -1) 374 goto userout; 375 if (i == 0) 376 goto user; 377 378 if (i == SIGSEGV) 379 ucode = SEGV_MAPERR; 380 else { 381 if (prot_fault_translation == 0) { 382 /* 383 * Autodetect. 384 * This check also covers the images 385 * without the ABI-tag ELF note. 386 */ 387 if (p->p_osrel >= 700004) { 388 i = SIGSEGV; 389 ucode = SEGV_ACCERR; 390 } else { 391 i = SIGBUS; 392 ucode = BUS_PAGE_FAULT; 393 } 394 } else if (prot_fault_translation == 1) { 395 /* 396 * Always compat mode. 397 */ 398 i = SIGBUS; 399 ucode = BUS_PAGE_FAULT; 400 } else { 401 /* 402 * Always SIGSEGV mode. 403 */ 404 i = SIGSEGV; 405 ucode = SEGV_ACCERR; 406 } 407 } 408 addr = eva; 409 break; 410 411 case T_DIVIDE: /* integer divide fault */ 412 ucode = FPE_INTDIV; 413 i = SIGFPE; 414 break; 415 416 #ifdef DEV_ISA 417 case T_NMI: 418 #ifdef POWERFAIL_NMI 419 #ifndef TIMER_FREQ 420 # define TIMER_FREQ 1193182 421 #endif 422 mtx_lock(&Giant); 423 if (time_second - lastalert > 10) { 424 log(LOG_WARNING, "NMI: power fail\n"); 425 sysbeep(TIMER_FREQ/880, hz); 426 lastalert = time_second; 427 } 428 mtx_unlock(&Giant); 429 goto userout; 430 #else /* !POWERFAIL_NMI */ 431 /* machine/parity/power fail/"kitchen sink" faults */ 432 /* XXX Giant */ 433 if (isa_nmi(code) == 0) { 434 #ifdef KDB 435 /* 436 * NMI can be hooked up to a pushbutton 437 * for debugging. 438 */ 439 if (kdb_on_nmi) { 440 printf ("NMI ... going to debugger\n"); 441 kdb_trap(type, 0, frame); 442 } 443 #endif /* KDB */ 444 goto userout; 445 } else if (panic_on_nmi) 446 panic("NMI indicates hardware failure"); 447 break; 448 #endif /* POWERFAIL_NMI */ 449 #endif /* DEV_ISA */ 450 451 case T_OFLOW: /* integer overflow fault */ 452 ucode = FPE_INTOVF; 453 i = SIGFPE; 454 break; 455 456 case T_BOUND: /* bounds check fault */ 457 ucode = FPE_FLTSUB; 458 i = SIGFPE; 459 break; 460 461 case T_DNA: 462 #ifdef DEV_NPX 463 /* transparent fault (due to context switch "late") */ 464 if (npxdna()) 465 goto userout; 466 #endif 467 printf("pid %d killed due to lack of floating point\n", 468 p->p_pid); 469 i = SIGKILL; 470 ucode = 0; 471 break; 472 473 case T_FPOPFLT: /* FPU operand fetch fault */ 474 ucode = ILL_COPROC; 475 i = SIGILL; 476 break; 477 478 case T_XMMFLT: /* SIMD floating-point exception */ 479 ucode = 0; /* XXX */ 480 i = SIGFPE; 481 break; 482 } 483 } else { 484 /* kernel trap */ 485 486 KASSERT(cold || td->td_ucred != NULL, 487 ("kernel trap doesn't have ucred")); 488 switch (type) { 489 case T_PAGEFLT: /* page fault */ 490 (void) trap_pfault(frame, FALSE, eva); 491 goto out; 492 493 case T_DNA: 494 #ifdef DEV_NPX 495 /* 496 * The kernel is apparently using npx for copying. 497 * XXX this should be fatal unless the kernel has 498 * registered such use. 499 */ 500 if (npxdna()) 501 goto out; 502 #endif 503 break; 504 505 /* 506 * The following two traps can happen in 507 * vm86 mode, and, if so, we want to handle 508 * them specially. 509 */ 510 case T_PROTFLT: /* general protection fault */ 511 case T_STKFLT: /* stack fault */ 512 if (frame->tf_eflags & PSL_VM) { 513 i = vm86_emulate((struct vm86frame *)frame); 514 if (i != 0) 515 /* 516 * returns to original process 517 */ 518 vm86_trap((struct vm86frame *)frame); 519 goto out; 520 } 521 if (type == T_STKFLT) 522 break; 523 524 /* FALL THROUGH */ 525 526 case T_SEGNPFLT: /* segment not present fault */ 527 if (PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL) 528 break; 529 530 /* 531 * Invalid %fs's and %gs's can be created using 532 * procfs or PT_SETREGS or by invalidating the 533 * underlying LDT entry. This causes a fault 534 * in kernel mode when the kernel attempts to 535 * switch contexts. Lose the bad context 536 * (XXX) so that we can continue, and generate 537 * a signal. 538 */ 539 if (frame->tf_eip == (int)cpu_switch_load_gs) { 540 PCPU_GET(curpcb)->pcb_gs = 0; 541 #if 0 542 PROC_LOCK(p); 543 psignal(p, SIGBUS); 544 PROC_UNLOCK(p); 545 #endif 546 goto out; 547 } 548 549 if (td->td_intr_nesting_level != 0) 550 break; 551 552 /* 553 * Invalid segment selectors and out of bounds 554 * %eip's and %esp's can be set up in user mode. 555 * This causes a fault in kernel mode when the 556 * kernel tries to return to user mode. We want 557 * to get this fault so that we can fix the 558 * problem here and not have to check all the 559 * selectors and pointers when the user changes 560 * them. 561 */ 562 if (frame->tf_eip == (int)doreti_iret) { 563 frame->tf_eip = (int)doreti_iret_fault; 564 goto out; 565 } 566 if (frame->tf_eip == (int)doreti_popl_ds) { 567 frame->tf_eip = (int)doreti_popl_ds_fault; 568 goto out; 569 } 570 if (frame->tf_eip == (int)doreti_popl_es) { 571 frame->tf_eip = (int)doreti_popl_es_fault; 572 goto out; 573 } 574 if (frame->tf_eip == (int)doreti_popl_fs) { 575 frame->tf_eip = (int)doreti_popl_fs_fault; 576 goto out; 577 } 578 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 579 frame->tf_eip = 580 (int)PCPU_GET(curpcb)->pcb_onfault; 581 goto out; 582 } 583 break; 584 585 case T_TSSFLT: 586 /* 587 * PSL_NT can be set in user mode and isn't cleared 588 * automatically when the kernel is entered. This 589 * causes a TSS fault when the kernel attempts to 590 * `iret' because the TSS link is uninitialized. We 591 * want to get this fault so that we can fix the 592 * problem here and not every time the kernel is 593 * entered. 594 */ 595 if (frame->tf_eflags & PSL_NT) { 596 frame->tf_eflags &= ~PSL_NT; 597 goto out; 598 } 599 break; 600 601 case T_TRCTRAP: /* trace trap */ 602 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) { 603 /* 604 * We've just entered system mode via the 605 * syscall lcall. Continue single stepping 606 * silently until the syscall handler has 607 * saved the flags. 608 */ 609 goto out; 610 } 611 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 612 /* 613 * The syscall handler has now saved the 614 * flags. Stop single stepping it. 615 */ 616 frame->tf_eflags &= ~PSL_T; 617 goto out; 618 } 619 /* 620 * Ignore debug register trace traps due to 621 * accesses in the user's address space, which 622 * can happen under several conditions such as 623 * if a user sets a watchpoint on a buffer and 624 * then passes that buffer to a system call. 625 * We still want to get TRCTRAPS for addresses 626 * in kernel space because that is useful when 627 * debugging the kernel. 628 */ 629 /* XXX Giant */ 630 if (user_dbreg_trap() && 631 !(PCPU_GET(curpcb)->pcb_flags & PCB_VM86CALL)) { 632 /* 633 * Reset breakpoint bits because the 634 * processor doesn't 635 */ 636 load_dr6(rdr6() & 0xfffffff0); 637 goto out; 638 } 639 /* 640 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 641 */ 642 case T_BPTFLT: 643 /* 644 * If KDB is enabled, let it handle the debugger trap. 645 * Otherwise, debugger traps "can't happen". 646 */ 647 #ifdef KDB 648 if (kdb_trap(type, 0, frame)) 649 goto out; 650 #endif 651 break; 652 653 #ifdef DEV_ISA 654 case T_NMI: 655 #ifdef POWERFAIL_NMI 656 mtx_lock(&Giant); 657 if (time_second - lastalert > 10) { 658 log(LOG_WARNING, "NMI: power fail\n"); 659 sysbeep(TIMER_FREQ/880, hz); 660 lastalert = time_second; 661 } 662 mtx_unlock(&Giant); 663 goto out; 664 #else /* !POWERFAIL_NMI */ 665 /* XXX Giant */ 666 /* machine/parity/power fail/"kitchen sink" faults */ 667 if (isa_nmi(code) == 0) { 668 #ifdef KDB 669 /* 670 * NMI can be hooked up to a pushbutton 671 * for debugging. 672 */ 673 if (kdb_on_nmi) { 674 printf ("NMI ... going to debugger\n"); 675 kdb_trap(type, 0, frame); 676 } 677 #endif /* KDB */ 678 goto out; 679 } else if (panic_on_nmi == 0) 680 goto out; 681 /* FALLTHROUGH */ 682 #endif /* POWERFAIL_NMI */ 683 #endif /* DEV_ISA */ 684 } 685 686 trap_fatal(frame, eva); 687 goto out; 688 } 689 690 /* Translate fault for emulators (e.g. Linux) */ 691 if (*p->p_sysent->sv_transtrap) 692 i = (*p->p_sysent->sv_transtrap)(i, type); 693 694 ksiginfo_init_trap(&ksi); 695 ksi.ksi_signo = i; 696 ksi.ksi_code = ucode; 697 ksi.ksi_addr = (void *)addr; 698 ksi.ksi_trapno = type; 699 trapsignal(td, &ksi); 700 701 #ifdef DEBUG 702 if (type <= MAX_TRAP_MSG) { 703 uprintf("fatal process exception: %s", 704 trap_msg[type]); 705 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 706 uprintf(", fault VA = 0x%lx", (u_long)eva); 707 uprintf("\n"); 708 } 709 #endif 710 711 user: 712 userret(td, frame); 713 mtx_assert(&Giant, MA_NOTOWNED); 714 userout: 715 out: 716 return; 717 } 718 719 static int 720 trap_pfault(frame, usermode, eva) 721 struct trapframe *frame; 722 int usermode; 723 vm_offset_t eva; 724 { 725 vm_offset_t va; 726 struct vmspace *vm = NULL; 727 vm_map_t map; 728 int rv = 0; 729 vm_prot_t ftype; 730 struct thread *td = curthread; 731 struct proc *p = td->td_proc; 732 733 va = trunc_page(eva); 734 if (va >= KERNBASE) { 735 /* 736 * Don't allow user-mode faults in kernel address space. 737 * An exception: if the faulting address is the invalid 738 * instruction entry in the IDT, then the Intel Pentium 739 * F00F bug workaround was triggered, and we need to 740 * treat it is as an illegal instruction, and not a page 741 * fault. 742 */ 743 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 744 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) 745 return -2; 746 #endif 747 if (usermode) 748 goto nogo; 749 750 map = kernel_map; 751 } else { 752 /* 753 * This is a fault on non-kernel virtual memory. 754 * vm is initialized above to NULL. If curproc is NULL 755 * or curproc->p_vmspace is NULL the fault is fatal. 756 */ 757 if (p != NULL) 758 vm = p->p_vmspace; 759 760 if (vm == NULL) 761 goto nogo; 762 763 map = &vm->vm_map; 764 } 765 766 /* 767 * PGEX_I is defined only if the execute disable bit capability is 768 * supported and enabled. 769 */ 770 if (frame->tf_err & PGEX_W) 771 ftype = VM_PROT_WRITE; 772 #ifdef PAE 773 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 774 ftype = VM_PROT_EXECUTE; 775 #endif 776 else 777 ftype = VM_PROT_READ; 778 779 if (map != kernel_map) { 780 /* 781 * Keep swapout from messing with us during this 782 * critical time. 783 */ 784 PROC_LOCK(p); 785 ++p->p_lock; 786 PROC_UNLOCK(p); 787 788 /* Fault in the user page: */ 789 rv = vm_fault(map, va, ftype, 790 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 791 : VM_FAULT_NORMAL); 792 793 PROC_LOCK(p); 794 --p->p_lock; 795 PROC_UNLOCK(p); 796 } else { 797 /* 798 * Don't have to worry about process locking or stacks in the 799 * kernel. 800 */ 801 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 802 } 803 if (rv == KERN_SUCCESS) 804 return (0); 805 nogo: 806 if (!usermode) { 807 if (td->td_intr_nesting_level == 0 && 808 PCPU_GET(curpcb)->pcb_onfault != NULL) { 809 frame->tf_eip = (int)PCPU_GET(curpcb)->pcb_onfault; 810 return (0); 811 } 812 trap_fatal(frame, eva); 813 return (-1); 814 } 815 816 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 817 } 818 819 static void 820 trap_fatal(frame, eva) 821 struct trapframe *frame; 822 vm_offset_t eva; 823 { 824 int code, ss, esp; 825 u_int type; 826 struct soft_segment_descriptor softseg; 827 char *msg; 828 829 code = frame->tf_err; 830 type = frame->tf_trapno; 831 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 832 833 if (type <= MAX_TRAP_MSG) 834 msg = trap_msg[type]; 835 else 836 msg = "UNKNOWN"; 837 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 838 frame->tf_eflags & PSL_VM ? "vm86" : 839 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 840 #ifdef SMP 841 /* two separate prints in case of a trap on an unmapped page */ 842 printf("cpuid = %d; ", PCPU_GET(cpuid)); 843 printf("apic id = %02x\n", PCPU_GET(apic_id)); 844 #endif 845 if (type == T_PAGEFLT) { 846 printf("fault virtual address = 0x%x\n", eva); 847 printf("fault code = %s %s, %s\n", 848 code & PGEX_U ? "user" : "supervisor", 849 code & PGEX_W ? "write" : "read", 850 code & PGEX_P ? "protection violation" : "page not present"); 851 } 852 printf("instruction pointer = 0x%x:0x%x\n", 853 frame->tf_cs & 0xffff, frame->tf_eip); 854 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 855 ss = frame->tf_ss & 0xffff; 856 esp = frame->tf_esp; 857 } else { 858 ss = GSEL(GDATA_SEL, SEL_KPL); 859 esp = (int)&frame->tf_esp; 860 } 861 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 862 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 863 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 864 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 865 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 866 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 867 softseg.ssd_gran); 868 printf("processor eflags = "); 869 if (frame->tf_eflags & PSL_T) 870 printf("trace trap, "); 871 if (frame->tf_eflags & PSL_I) 872 printf("interrupt enabled, "); 873 if (frame->tf_eflags & PSL_NT) 874 printf("nested task, "); 875 if (frame->tf_eflags & PSL_RF) 876 printf("resume, "); 877 if (frame->tf_eflags & PSL_VM) 878 printf("vm86, "); 879 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 880 printf("current process = "); 881 if (curproc) { 882 printf("%lu (%s)\n", (u_long)curproc->p_pid, curproc->p_comm); 883 } else { 884 printf("Idle\n"); 885 } 886 887 #ifdef KDB 888 if (debugger_on_panic || kdb_active) { 889 frame->tf_err = eva; /* smuggle fault address to ddb */ 890 if (kdb_trap(type, 0, frame)) { 891 frame->tf_err = code; /* restore error code */ 892 return; 893 } 894 frame->tf_err = code; /* restore error code */ 895 } 896 #endif 897 printf("trap number = %d\n", type); 898 if (type <= MAX_TRAP_MSG) 899 panic("%s", trap_msg[type]); 900 else 901 panic("unknown/reserved trap"); 902 } 903 904 /* 905 * Double fault handler. Called when a fault occurs while writing 906 * a frame for a trap/exception onto the stack. This usually occurs 907 * when the stack overflows (such is the case with infinite recursion, 908 * for example). 909 * 910 * XXX Note that the current PTD gets replaced by IdlePTD when the 911 * task switch occurs. This means that the stack that was active at 912 * the time of the double fault is not available at <kstack> unless 913 * the machine was idle when the double fault occurred. The downside 914 * of this is that "trace <ebp>" in ddb won't work. 915 */ 916 void 917 dblfault_handler() 918 { 919 printf("\nFatal double fault:\n"); 920 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 921 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 922 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 923 #ifdef SMP 924 /* two separate prints in case of a trap on an unmapped page */ 925 printf("cpuid = %d; ", PCPU_GET(cpuid)); 926 printf("apic id = %02x\n", PCPU_GET(apic_id)); 927 #endif 928 panic("double fault"); 929 } 930 931 /* 932 * syscall - system call request C handler 933 * 934 * A system call is essentially treated as a trap. 935 */ 936 void 937 syscall(struct trapframe *frame) 938 { 939 caddr_t params; 940 struct sysent *callp; 941 struct thread *td = curthread; 942 struct proc *p = td->td_proc; 943 register_t orig_tf_eflags; 944 int error; 945 int narg; 946 int args[8]; 947 u_int code; 948 ksiginfo_t ksi; 949 950 PCPU_INC(cnt.v_syscall); 951 952 #ifdef DIAGNOSTIC 953 if (ISPL(frame->tf_cs) != SEL_UPL) { 954 panic("syscall"); 955 /* NOT REACHED */ 956 } 957 #endif 958 959 td->td_pticks = 0; 960 td->td_frame = frame; 961 if (td->td_ucred != p->p_ucred) 962 cred_update_thread(td); 963 #ifdef KSE 964 if (p->p_flag & P_SA) 965 thread_user_enter(td); 966 #endif 967 params = (caddr_t)frame->tf_esp + sizeof(int); 968 code = frame->tf_eax; 969 orig_tf_eflags = frame->tf_eflags; 970 971 if (p->p_sysent->sv_prepsyscall) { 972 /* 973 * The prep code is MP aware. 974 */ 975 (*p->p_sysent->sv_prepsyscall)(frame, args, &code, ¶ms); 976 } else { 977 /* 978 * Need to check if this is a 32 bit or 64 bit syscall. 979 * fuword is MP aware. 980 */ 981 if (code == SYS_syscall) { 982 /* 983 * Code is first argument, followed by actual args. 984 */ 985 code = fuword(params); 986 params += sizeof(int); 987 } else if (code == SYS___syscall) { 988 /* 989 * Like syscall, but code is a quad, so as to maintain 990 * quad alignment for the rest of the arguments. 991 */ 992 code = fuword(params); 993 params += sizeof(quad_t); 994 } 995 } 996 997 if (p->p_sysent->sv_mask) 998 code &= p->p_sysent->sv_mask; 999 1000 if (code >= p->p_sysent->sv_size) 1001 callp = &p->p_sysent->sv_table[0]; 1002 else 1003 callp = &p->p_sysent->sv_table[code]; 1004 1005 narg = callp->sy_narg; 1006 1007 /* 1008 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 1009 */ 1010 if (params != NULL && narg != 0) 1011 error = copyin(params, (caddr_t)args, 1012 (u_int)(narg * sizeof(int))); 1013 else 1014 error = 0; 1015 1016 #ifdef KTRACE 1017 if (KTRPOINT(td, KTR_SYSCALL)) 1018 ktrsyscall(code, narg, args); 1019 #endif 1020 1021 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 1022 td->td_proc->p_pid, td->td_proc->p_comm, code); 1023 1024 td->td_syscalls++; 1025 1026 if (error == 0) { 1027 td->td_retval[0] = 0; 1028 td->td_retval[1] = frame->tf_edx; 1029 1030 STOPEVENT(p, S_SCE, narg); 1031 1032 PTRACESTOP_SC(p, td, S_PT_SCE); 1033 1034 AUDIT_SYSCALL_ENTER(code, td); 1035 error = (*callp->sy_call)(td, args); 1036 AUDIT_SYSCALL_EXIT(error, td); 1037 } 1038 1039 switch (error) { 1040 case 0: 1041 frame->tf_eax = td->td_retval[0]; 1042 frame->tf_edx = td->td_retval[1]; 1043 frame->tf_eflags &= ~PSL_C; 1044 break; 1045 1046 case ERESTART: 1047 /* 1048 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 1049 * int 0x80 is 2 bytes. We saved this in tf_err. 1050 */ 1051 frame->tf_eip -= frame->tf_err; 1052 break; 1053 1054 case EJUSTRETURN: 1055 break; 1056 1057 default: 1058 if (p->p_sysent->sv_errsize) { 1059 if (error >= p->p_sysent->sv_errsize) 1060 error = -1; /* XXX */ 1061 else 1062 error = p->p_sysent->sv_errtbl[error]; 1063 } 1064 frame->tf_eax = error; 1065 frame->tf_eflags |= PSL_C; 1066 break; 1067 } 1068 1069 /* 1070 * Traced syscall. 1071 */ 1072 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { 1073 frame->tf_eflags &= ~PSL_T; 1074 ksiginfo_init_trap(&ksi); 1075 ksi.ksi_signo = SIGTRAP; 1076 ksi.ksi_code = TRAP_TRACE; 1077 ksi.ksi_addr = (void *)frame->tf_eip; 1078 trapsignal(td, &ksi); 1079 } 1080 1081 /* 1082 * Check for misbehavior. 1083 */ 1084 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 1085 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 1086 KASSERT(td->td_critnest == 0, 1087 ("System call %s returning in a critical section", 1088 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???")); 1089 KASSERT(td->td_locks == 0, 1090 ("System call %s returning with %d locks held", 1091 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???", 1092 td->td_locks)); 1093 1094 /* 1095 * Handle reschedule and other end-of-syscall issues 1096 */ 1097 userret(td, frame); 1098 1099 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 1100 td->td_proc->p_pid, td->td_proc->p_comm, code); 1101 1102 #ifdef KTRACE 1103 if (KTRPOINT(td, KTR_SYSRET)) 1104 ktrsysret(code, error, td->td_retval[0]); 1105 #endif 1106 1107 /* 1108 * This works because errno is findable through the 1109 * register set. If we ever support an emulation where this 1110 * is not the case, this code will need to be revisited. 1111 */ 1112 STOPEVENT(p, S_SCX, code); 1113 1114 PTRACESTOP_SC(p, td, S_PT_SCX); 1115 } 1116
Cache object: d31c6ddee296f701983282f5b57cfaee
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