trap.c revision 308418
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: stable/11/sys/i386/i386/trap.c 308418 2016-11-07 12:10:17Z 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_npx.h" 53#include "opt_stack.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 HWPMC_HOOKS 75#include <sys/pmckern.h> 76PMC_SOFT_DEFINE( , , page_fault, all); 77PMC_SOFT_DEFINE( , , page_fault, read); 78PMC_SOFT_DEFINE( , , page_fault, write); 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 <x86/mca.h> 93#include <machine/md_var.h> 94#include <machine/pcb.h> 95#ifdef SMP 96#include <machine/smp.h> 97#endif 98#include <machine/stack.h> 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#endif 110 111extern void trap(struct trapframe *frame); 112extern void syscall(struct trapframe *frame); 113 114static int trap_pfault(struct trapframe *, int, vm_offset_t); 115static void trap_fatal(struct trapframe *, vm_offset_t); 116void dblfault_handler(void); 117 118extern inthand_t IDTVEC(lcall_syscall); 119 120#define MAX_TRAP_MSG 32 121static char *trap_msg[] = { 122 "", /* 0 unused */ 123 "privileged instruction fault", /* 1 T_PRIVINFLT */ 124 "", /* 2 unused */ 125 "breakpoint instruction fault", /* 3 T_BPTFLT */ 126 "", /* 4 unused */ 127 "", /* 5 unused */ 128 "arithmetic trap", /* 6 T_ARITHTRAP */ 129 "", /* 7 unused */ 130 "", /* 8 unused */ 131 "general protection fault", /* 9 T_PROTFLT */ 132 "trace trap", /* 10 T_TRCTRAP */ 133 "", /* 11 unused */ 134 "page fault", /* 12 T_PAGEFLT */ 135 "", /* 13 unused */ 136 "alignment fault", /* 14 T_ALIGNFLT */ 137 "", /* 15 unused */ 138 "", /* 16 unused */ 139 "", /* 17 unused */ 140 "integer divide fault", /* 18 T_DIVIDE */ 141 "non-maskable interrupt trap", /* 19 T_NMI */ 142 "overflow trap", /* 20 T_OFLOW */ 143 "FPU bounds check fault", /* 21 T_BOUND */ 144 "FPU device not available", /* 22 T_DNA */ 145 "double fault", /* 23 T_DOUBLEFLT */ 146 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 147 "invalid TSS fault", /* 25 T_TSSFLT */ 148 "segment not present fault", /* 26 T_SEGNPFLT */ 149 "stack fault", /* 27 T_STKFLT */ 150 "machine check trap", /* 28 T_MCHK */ 151 "SIMD floating-point exception", /* 29 T_XMMFLT */ 152 "reserved (unknown) fault", /* 30 T_RESERVED */ 153 "", /* 31 unused (reserved) */ 154 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 155}; 156 157#if defined(I586_CPU) && !defined(NO_F00F_HACK) 158int has_f00f_bug = 0; /* Initialized so that it can be patched. */ 159#endif 160 161#ifdef KDB 162static int kdb_on_nmi = 1; 163SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RWTUN, 164 &kdb_on_nmi, 0, "Go to KDB on NMI"); 165#endif 166static int panic_on_nmi = 1; 167SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RWTUN, 168 &panic_on_nmi, 0, "Panic on NMI"); 169static int prot_fault_translation = 0; 170SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 171 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 172static int uprintf_signal; 173SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW, 174 &uprintf_signal, 0, 175 "Print debugging information on trap signal to ctty"); 176 177/* 178 * Exception, fault, and trap interface to the FreeBSD kernel. 179 * This common code is called from assembly language IDT gate entry 180 * routines that prepare a suitable stack frame, and restore this 181 * frame after the exception has been processed. 182 */ 183 184void 185trap(struct trapframe *frame) 186{ 187#ifdef KDTRACE_HOOKS 188 struct reg regs; 189#endif 190 struct thread *td = curthread; 191 struct proc *p = td->td_proc; 192#ifdef KDB 193 register_t dr6; 194#endif 195 int i = 0, ucode = 0; 196 u_int type; 197 register_t addr = 0; 198 vm_offset_t eva; 199 ksiginfo_t ksi; 200#ifdef POWERFAIL_NMI 201 static int lastalert = 0; 202#endif 203 204 PCPU_INC(cnt.v_trap); 205 type = frame->tf_trapno; 206 207#ifdef SMP 208 /* Handler for NMI IPIs used for stopping CPUs. */ 209 if (type == T_NMI) { 210 if (ipi_nmi_handler() == 0) 211 goto out; 212 } 213#endif /* SMP */ 214 215#ifdef KDB 216 if (kdb_active) { 217 kdb_reenter(); 218 goto out; 219 } 220#endif 221 222 if (type == T_RESERVED) { 223 trap_fatal(frame, 0); 224 goto out; 225 } 226 227 if (type == T_NMI) { 228#ifdef HWPMC_HOOKS 229 /* 230 * CPU PMCs interrupt using an NMI so we check for that first. 231 * If the HWPMC module is active, 'pmc_hook' will point to 232 * the function to be called. A non-zero return value from the 233 * hook means that the NMI was consumed by it and that we can 234 * return immediately. 235 */ 236 if (pmc_intr != NULL && 237 (*pmc_intr)(PCPU_GET(cpuid), frame) != 0) 238 goto out; 239#endif 240 241#ifdef STACK 242 if (stack_nmi_handler(frame) != 0) 243 goto out; 244#endif 245 } 246 247 if (type == T_MCHK) { 248 mca_intr(); 249 goto out; 250 } 251 252#ifdef KDTRACE_HOOKS 253 /* 254 * A trap can occur while DTrace executes a probe. Before 255 * executing the probe, DTrace blocks re-scheduling and sets 256 * a flag in its per-cpu flags to indicate that it doesn't 257 * want to fault. On returning from the probe, the no-fault 258 * flag is cleared and finally re-scheduling is enabled. 259 */ 260 if ((type == T_PROTFLT || type == T_PAGEFLT) && 261 dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type)) 262 goto out; 263#endif 264 265 if ((frame->tf_eflags & PSL_I) == 0) { 266 /* 267 * Buggy application or kernel code has disabled 268 * interrupts and then trapped. Enabling interrupts 269 * now is wrong, but it is better than running with 270 * interrupts disabled until they are accidentally 271 * enabled later. 272 */ 273 if (TRAPF_USERMODE(frame) && 274 (curpcb->pcb_flags & PCB_VM86CALL) == 0) 275 uprintf( 276 "pid %ld (%s): trap %d with interrupts disabled\n", 277 (long)curproc->p_pid, curthread->td_name, type); 278 else if (type != T_NMI && type != T_BPTFLT && 279 type != T_TRCTRAP && 280 frame->tf_eip != (int)cpu_switch_load_gs) { 281 /* 282 * XXX not quite right, since this may be for a 283 * multiple fault in user mode. 284 */ 285 printf("kernel trap %d with interrupts disabled\n", 286 type); 287 /* 288 * Page faults need interrupts disabled until later, 289 * and we shouldn't enable interrupts while holding 290 * a spin lock. 291 */ 292 if (type != T_PAGEFLT && 293 td->td_md.md_spinlock_count == 0) 294 enable_intr(); 295 } 296 } 297 eva = 0; 298 if (type == T_PAGEFLT) { 299 /* 300 * For some Cyrix CPUs, %cr2 is clobbered by 301 * interrupts. This problem is worked around by using 302 * an interrupt gate for the pagefault handler. We 303 * are finally ready to read %cr2 and conditionally 304 * reenable interrupts. If we hold a spin lock, then 305 * we must not reenable interrupts. This might be a 306 * spurious page fault. 307 */ 308 eva = rcr2(); 309 if (td->td_md.md_spinlock_count == 0) 310 enable_intr(); 311 } 312 313 if (TRAPF_USERMODE(frame) && (curpcb->pcb_flags & PCB_VM86CALL) == 0) { 314 /* user trap */ 315 316 td->td_pticks = 0; 317 td->td_frame = frame; 318 addr = frame->tf_eip; 319 if (td->td_cowgen != p->p_cowgen) 320 thread_cow_update(td); 321 322 switch (type) { 323 case T_PRIVINFLT: /* privileged instruction fault */ 324 i = SIGILL; 325 ucode = ILL_PRVOPC; 326 break; 327 328 case T_BPTFLT: /* bpt instruction fault */ 329 case T_TRCTRAP: /* trace trap */ 330 enable_intr(); 331#ifdef KDTRACE_HOOKS 332 if (type == T_BPTFLT) { 333 fill_frame_regs(frame, ®s); 334 if (dtrace_pid_probe_ptr != NULL && 335 dtrace_pid_probe_ptr(®s) == 0) 336 goto out; 337 } 338#endif 339user_trctrap_out: 340 frame->tf_eflags &= ~PSL_T; 341 i = SIGTRAP; 342 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 343 break; 344 345 case T_ARITHTRAP: /* arithmetic trap */ 346#ifdef DEV_NPX 347 ucode = npxtrap_x87(); 348 if (ucode == -1) 349 goto userout; 350#else 351 ucode = 0; 352#endif 353 i = SIGFPE; 354 break; 355 356 /* 357 * The following two traps can happen in 358 * vm86 mode, and, if so, we want to handle 359 * them specially. 360 */ 361 case T_PROTFLT: /* general protection fault */ 362 case T_STKFLT: /* stack fault */ 363 if (frame->tf_eflags & PSL_VM) { 364 i = vm86_emulate((struct vm86frame *)frame); 365 if (i == SIGTRAP) { 366 type = T_TRCTRAP; 367 load_dr6(rdr6() | 0x4000); 368 goto user_trctrap_out; 369 } 370 if (i == 0) 371 goto user; 372 break; 373 } 374 i = SIGBUS; 375 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; 376 break; 377 case T_SEGNPFLT: /* segment not present fault */ 378 i = SIGBUS; 379 ucode = BUS_ADRERR; 380 break; 381 case T_TSSFLT: /* invalid TSS fault */ 382 i = SIGBUS; 383 ucode = BUS_OBJERR; 384 break; 385 case T_ALIGNFLT: 386 i = SIGBUS; 387 ucode = BUS_ADRALN; 388 break; 389 case T_DOUBLEFLT: /* double fault */ 390 default: 391 i = SIGBUS; 392 ucode = BUS_OBJERR; 393 break; 394 395 case T_PAGEFLT: /* page fault */ 396 397 i = trap_pfault(frame, TRUE, eva); 398#if defined(I586_CPU) && !defined(NO_F00F_HACK) 399 if (i == -2) { 400 /* 401 * The f00f hack workaround has triggered, so 402 * treat the fault as an illegal instruction 403 * (T_PRIVINFLT) instead of a page fault. 404 */ 405 type = frame->tf_trapno = T_PRIVINFLT; 406 407 /* Proceed as in that case. */ 408 ucode = ILL_PRVOPC; 409 i = SIGILL; 410 break; 411 } 412#endif 413 if (i == -1) 414 goto userout; 415 if (i == 0) 416 goto user; 417 418 if (i == SIGSEGV) 419 ucode = SEGV_MAPERR; 420 else { 421 if (prot_fault_translation == 0) { 422 /* 423 * Autodetect. 424 * This check also covers the images 425 * without the ABI-tag ELF note. 426 */ 427 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 428 && p->p_osrel >= P_OSREL_SIGSEGV) { 429 i = SIGSEGV; 430 ucode = SEGV_ACCERR; 431 } else { 432 i = SIGBUS; 433 ucode = BUS_PAGE_FAULT; 434 } 435 } else if (prot_fault_translation == 1) { 436 /* 437 * Always compat mode. 438 */ 439 i = SIGBUS; 440 ucode = BUS_PAGE_FAULT; 441 } else { 442 /* 443 * Always SIGSEGV mode. 444 */ 445 i = SIGSEGV; 446 ucode = SEGV_ACCERR; 447 } 448 } 449 addr = eva; 450 break; 451 452 case T_DIVIDE: /* integer divide fault */ 453 ucode = FPE_INTDIV; 454 i = SIGFPE; 455 break; 456 457#ifdef DEV_ISA 458 case T_NMI: 459#ifdef POWERFAIL_NMI 460#ifndef TIMER_FREQ 461# define TIMER_FREQ 1193182 462#endif 463 if (time_second - lastalert > 10) { 464 log(LOG_WARNING, "NMI: power fail\n"); 465 sysbeep(880, hz); 466 lastalert = time_second; 467 } 468 goto userout; 469#else /* !POWERFAIL_NMI */ 470 /* machine/parity/power fail/"kitchen sink" faults */ 471 if (isa_nmi(frame->tf_err) == 0) { 472#ifdef KDB 473 /* 474 * NMI can be hooked up to a pushbutton 475 * for debugging. 476 */ 477 if (kdb_on_nmi) { 478 printf ("NMI ... going to debugger\n"); 479 kdb_trap(type, 0, frame); 480 } 481#endif /* KDB */ 482 goto userout; 483 } else if (panic_on_nmi) 484 panic("NMI indicates hardware failure"); 485 break; 486#endif /* POWERFAIL_NMI */ 487#endif /* DEV_ISA */ 488 489 case T_OFLOW: /* integer overflow fault */ 490 ucode = FPE_INTOVF; 491 i = SIGFPE; 492 break; 493 494 case T_BOUND: /* bounds check fault */ 495 ucode = FPE_FLTSUB; 496 i = SIGFPE; 497 break; 498 499 case T_DNA: 500#ifdef DEV_NPX 501 KASSERT(PCB_USER_FPU(td->td_pcb), 502 ("kernel FPU ctx has leaked")); 503 /* transparent fault (due to context switch "late") */ 504 if (npxdna()) 505 goto userout; 506#endif 507 uprintf("pid %d killed due to lack of floating point\n", 508 p->p_pid); 509 i = SIGKILL; 510 ucode = 0; 511 break; 512 513 case T_FPOPFLT: /* FPU operand fetch fault */ 514 ucode = ILL_COPROC; 515 i = SIGILL; 516 break; 517 518 case T_XMMFLT: /* SIMD floating-point exception */ 519#if defined(DEV_NPX) && !defined(CPU_DISABLE_SSE) && defined(I686_CPU) 520 ucode = npxtrap_sse(); 521 if (ucode == -1) 522 goto userout; 523#else 524 ucode = 0; 525#endif 526 i = SIGFPE; 527 break; 528#ifdef KDTRACE_HOOKS 529 case T_DTRACE_RET: 530 enable_intr(); 531 fill_frame_regs(frame, ®s); 532 if (dtrace_return_probe_ptr != NULL && 533 dtrace_return_probe_ptr(®s) == 0) 534 goto out; 535 break; 536#endif 537 } 538 } else { 539 /* kernel trap */ 540 541 KASSERT(cold || td->td_ucred != NULL, 542 ("kernel trap doesn't have ucred")); 543 switch (type) { 544 case T_PAGEFLT: /* page fault */ 545 (void) trap_pfault(frame, FALSE, eva); 546 goto out; 547 548 case T_DNA: 549#ifdef DEV_NPX 550 if (PCB_USER_FPU(td->td_pcb)) 551 panic("Unregistered use of FPU in kernel"); 552 if (npxdna()) 553 goto out; 554#endif 555 break; 556 557 case T_ARITHTRAP: /* arithmetic trap */ 558 case T_XMMFLT: /* SIMD floating-point exception */ 559 case T_FPOPFLT: /* FPU operand fetch fault */ 560 /* 561 * XXXKIB for now disable any FPU traps in kernel 562 * handler registration seems to be overkill 563 */ 564 trap_fatal(frame, 0); 565 goto out; 566 567 /* 568 * The following two traps can happen in 569 * vm86 mode, and, if so, we want to handle 570 * them specially. 571 */ 572 case T_PROTFLT: /* general protection fault */ 573 case T_STKFLT: /* stack fault */ 574 if (frame->tf_eflags & PSL_VM) { 575 i = vm86_emulate((struct vm86frame *)frame); 576 if (i == SIGTRAP) { 577 type = T_TRCTRAP; 578 load_dr6(rdr6() | 0x4000); 579 goto kernel_trctrap; 580 } 581 if (i != 0) 582 /* 583 * returns to original process 584 */ 585 vm86_trap((struct vm86frame *)frame); 586 goto out; 587 } 588 if (type == T_STKFLT) 589 break; 590 591 /* FALL THROUGH */ 592 593 case T_SEGNPFLT: /* segment not present fault */ 594 if (curpcb->pcb_flags & PCB_VM86CALL) 595 break; 596 597 /* 598 * Invalid %fs's and %gs's can be created using 599 * procfs or PT_SETREGS or by invalidating the 600 * underlying LDT entry. This causes a fault 601 * in kernel mode when the kernel attempts to 602 * switch contexts. Lose the bad context 603 * (XXX) so that we can continue, and generate 604 * a signal. 605 */ 606 if (frame->tf_eip == (int)cpu_switch_load_gs) { 607 curpcb->pcb_gs = 0; 608#if 0 609 PROC_LOCK(p); 610 kern_psignal(p, SIGBUS); 611 PROC_UNLOCK(p); 612#endif 613 goto out; 614 } 615 616 if (td->td_intr_nesting_level != 0) 617 break; 618 619 /* 620 * Invalid segment selectors and out of bounds 621 * %eip's and %esp's can be set up in user mode. 622 * This causes a fault in kernel mode when the 623 * kernel tries to return to user mode. We want 624 * to get this fault so that we can fix the 625 * problem here and not have to check all the 626 * selectors and pointers when the user changes 627 * them. 628 */ 629 if (frame->tf_eip == (int)doreti_iret) { 630 frame->tf_eip = (int)doreti_iret_fault; 631 goto out; 632 } 633 if (frame->tf_eip == (int)doreti_popl_ds) { 634 frame->tf_eip = (int)doreti_popl_ds_fault; 635 goto out; 636 } 637 if (frame->tf_eip == (int)doreti_popl_es) { 638 frame->tf_eip = (int)doreti_popl_es_fault; 639 goto out; 640 } 641 if (frame->tf_eip == (int)doreti_popl_fs) { 642 frame->tf_eip = (int)doreti_popl_fs_fault; 643 goto out; 644 } 645 if (curpcb->pcb_onfault != NULL) { 646 frame->tf_eip = 647 (int)curpcb->pcb_onfault; 648 goto out; 649 } 650 break; 651 652 case T_TSSFLT: 653 /* 654 * PSL_NT can be set in user mode and isn't cleared 655 * automatically when the kernel is entered. This 656 * causes a TSS fault when the kernel attempts to 657 * `iret' because the TSS link is uninitialized. We 658 * want to get this fault so that we can fix the 659 * problem here and not every time the kernel is 660 * entered. 661 */ 662 if (frame->tf_eflags & PSL_NT) { 663 frame->tf_eflags &= ~PSL_NT; 664 goto out; 665 } 666 break; 667 668 case T_TRCTRAP: /* trace trap */ 669kernel_trctrap: 670 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) { 671 /* 672 * We've just entered system mode via the 673 * syscall lcall. Continue single stepping 674 * silently until the syscall handler has 675 * saved the flags. 676 */ 677 goto out; 678 } 679 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 680 /* 681 * The syscall handler has now saved the 682 * flags. Stop single stepping it. 683 */ 684 frame->tf_eflags &= ~PSL_T; 685 goto out; 686 } 687 /* 688 * Ignore debug register trace traps due to 689 * accesses in the user's address space, which 690 * can happen under several conditions such as 691 * if a user sets a watchpoint on a buffer and 692 * then passes that buffer to a system call. 693 * We still want to get TRCTRAPS for addresses 694 * in kernel space because that is useful when 695 * debugging the kernel. 696 */ 697 if (user_dbreg_trap() && 698 !(curpcb->pcb_flags & PCB_VM86CALL)) { 699 /* 700 * Reset breakpoint bits because the 701 * processor doesn't 702 */ 703 load_dr6(rdr6() & ~0xf); 704 goto out; 705 } 706 /* 707 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 708 */ 709 case T_BPTFLT: 710 /* 711 * If KDB is enabled, let it handle the debugger trap. 712 * Otherwise, debugger traps "can't happen". 713 */ 714#ifdef KDB 715 /* XXX %dr6 is not quite reentrant. */ 716 dr6 = rdr6(); 717 load_dr6(dr6 & ~0x4000); 718 if (kdb_trap(type, dr6, frame)) 719 goto out; 720#endif 721 break; 722 723#ifdef DEV_ISA 724 case T_NMI: 725#ifdef POWERFAIL_NMI 726 if (time_second - lastalert > 10) { 727 log(LOG_WARNING, "NMI: power fail\n"); 728 sysbeep(880, hz); 729 lastalert = time_second; 730 } 731 goto out; 732#else /* !POWERFAIL_NMI */ 733 /* machine/parity/power fail/"kitchen sink" faults */ 734 if (isa_nmi(frame->tf_err) == 0) { 735#ifdef KDB 736 /* 737 * NMI can be hooked up to a pushbutton 738 * for debugging. 739 */ 740 if (kdb_on_nmi) { 741 printf ("NMI ... going to debugger\n"); 742 kdb_trap(type, 0, frame); 743 } 744#endif /* KDB */ 745 goto out; 746 } else if (panic_on_nmi == 0) 747 goto out; 748 /* FALLTHROUGH */ 749#endif /* POWERFAIL_NMI */ 750#endif /* DEV_ISA */ 751 } 752 753 trap_fatal(frame, eva); 754 goto out; 755 } 756 757 /* Translate fault for emulators (e.g. Linux) */ 758 if (*p->p_sysent->sv_transtrap) 759 i = (*p->p_sysent->sv_transtrap)(i, type); 760 761 ksiginfo_init_trap(&ksi); 762 ksi.ksi_signo = i; 763 ksi.ksi_code = ucode; 764 ksi.ksi_addr = (void *)addr; 765 ksi.ksi_trapno = type; 766 if (uprintf_signal) { 767 uprintf("pid %d comm %s: signal %d err %x code %d type %d " 768 "addr 0x%x esp 0x%08x eip 0x%08x " 769 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 770 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 771 frame->tf_esp, frame->tf_eip, 772 fubyte((void *)(frame->tf_eip + 0)), 773 fubyte((void *)(frame->tf_eip + 1)), 774 fubyte((void *)(frame->tf_eip + 2)), 775 fubyte((void *)(frame->tf_eip + 3)), 776 fubyte((void *)(frame->tf_eip + 4)), 777 fubyte((void *)(frame->tf_eip + 5)), 778 fubyte((void *)(frame->tf_eip + 6)), 779 fubyte((void *)(frame->tf_eip + 7))); 780 } 781 KASSERT((read_eflags() & PSL_I) != 0, ("interrupts disabled")); 782 trapsignal(td, &ksi); 783 784#ifdef DEBUG 785 if (type <= MAX_TRAP_MSG) { 786 uprintf("fatal process exception: %s", 787 trap_msg[type]); 788 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 789 uprintf(", fault VA = 0x%lx", (u_long)eva); 790 uprintf("\n"); 791 } 792#endif 793 794user: 795 userret(td, frame); 796 KASSERT(PCB_USER_FPU(td->td_pcb), 797 ("Return from trap with kernel FPU ctx leaked")); 798userout: 799out: 800 return; 801} 802 803static int 804trap_pfault(frame, usermode, eva) 805 struct trapframe *frame; 806 int usermode; 807 vm_offset_t eva; 808{ 809 vm_offset_t va; 810 vm_map_t map; 811 int rv = 0; 812 vm_prot_t ftype; 813 struct thread *td = curthread; 814 struct proc *p = td->td_proc; 815 816 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 817 /* 818 * Due to both processor errata and lazy TLB invalidation when 819 * access restrictions are removed from virtual pages, memory 820 * accesses that are allowed by the physical mapping layer may 821 * nonetheless cause one spurious page fault per virtual page. 822 * When the thread is executing a "no faulting" section that 823 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 824 * every page fault is treated as a spurious page fault, 825 * unless it accesses the same virtual address as the most 826 * recent page fault within the same "no faulting" section. 827 */ 828 if (td->td_md.md_spurflt_addr != eva || 829 (td->td_pflags & TDP_RESETSPUR) != 0) { 830 /* 831 * Do nothing to the TLB. A stale TLB entry is 832 * flushed automatically by a page fault. 833 */ 834 td->td_md.md_spurflt_addr = eva; 835 td->td_pflags &= ~TDP_RESETSPUR; 836 return (0); 837 } 838 } else { 839 /* 840 * If we get a page fault while in a critical section, then 841 * it is most likely a fatal kernel page fault. The kernel 842 * is already going to panic trying to get a sleep lock to 843 * do the VM lookup, so just consider it a fatal trap so the 844 * kernel can print out a useful trap message and even get 845 * to the debugger. 846 * 847 * If we get a page fault while holding a non-sleepable 848 * lock, then it is most likely a fatal kernel page fault. 849 * If WITNESS is enabled, then it's going to whine about 850 * bogus LORs with various VM locks, so just skip to the 851 * fatal trap handling directly. 852 */ 853 if (td->td_critnest != 0 || 854 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 855 "Kernel page fault") != 0) { 856 trap_fatal(frame, eva); 857 return (-1); 858 } 859 } 860 va = trunc_page(eva); 861 if (va >= KERNBASE) { 862 /* 863 * Don't allow user-mode faults in kernel address space. 864 * An exception: if the faulting address is the invalid 865 * instruction entry in the IDT, then the Intel Pentium 866 * F00F bug workaround was triggered, and we need to 867 * treat it is as an illegal instruction, and not a page 868 * fault. 869 */ 870#if defined(I586_CPU) && !defined(NO_F00F_HACK) 871 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) 872 return (-2); 873#endif 874 if (usermode) 875 goto nogo; 876 877 map = kernel_map; 878 } else { 879 map = &p->p_vmspace->vm_map; 880 881 /* 882 * When accessing a user-space address, kernel must be 883 * ready to accept the page fault, and provide a 884 * handling routine. Since accessing the address 885 * without the handler is a bug, do not try to handle 886 * it normally, and panic immediately. 887 */ 888 if (!usermode && (td->td_intr_nesting_level != 0 || 889 curpcb->pcb_onfault == NULL)) { 890 trap_fatal(frame, eva); 891 return (-1); 892 } 893 } 894 895 /* 896 * PGEX_I is defined only if the execute disable bit capability is 897 * supported and enabled. 898 */ 899 if (frame->tf_err & PGEX_W) 900 ftype = VM_PROT_WRITE; 901#if defined(PAE) || defined(PAE_TABLES) 902 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 903 ftype = VM_PROT_EXECUTE; 904#endif 905 else 906 ftype = VM_PROT_READ; 907 908 /* Fault in the page. */ 909 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 910 if (rv == KERN_SUCCESS) { 911#ifdef HWPMC_HOOKS 912 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 913 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 914 if (ftype == VM_PROT_READ) 915 PMC_SOFT_CALL_TF( , , page_fault, read, 916 frame); 917 else 918 PMC_SOFT_CALL_TF( , , page_fault, write, 919 frame); 920 } 921#endif 922 return (0); 923 } 924nogo: 925 if (!usermode) { 926 if (td->td_intr_nesting_level == 0 && 927 curpcb->pcb_onfault != NULL) { 928 frame->tf_eip = (int)curpcb->pcb_onfault; 929 return (0); 930 } 931 trap_fatal(frame, eva); 932 return (-1); 933 } 934 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 935} 936 937static void 938trap_fatal(frame, eva) 939 struct trapframe *frame; 940 vm_offset_t eva; 941{ 942 int code, ss, esp; 943 u_int type; 944 struct soft_segment_descriptor softseg; 945 char *msg; 946 947 code = frame->tf_err; 948 type = frame->tf_trapno; 949 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 950 951 if (type <= MAX_TRAP_MSG) 952 msg = trap_msg[type]; 953 else 954 msg = "UNKNOWN"; 955 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 956 frame->tf_eflags & PSL_VM ? "vm86" : 957 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 958#ifdef SMP 959 /* two separate prints in case of a trap on an unmapped page */ 960 printf("cpuid = %d; ", PCPU_GET(cpuid)); 961 printf("apic id = %02x\n", PCPU_GET(apic_id)); 962#endif 963 if (type == T_PAGEFLT) { 964 printf("fault virtual address = 0x%x\n", eva); 965 printf("fault code = %s %s, %s\n", 966 code & PGEX_U ? "user" : "supervisor", 967 code & PGEX_W ? "write" : "read", 968 code & PGEX_P ? "protection violation" : "page not present"); 969 } 970 printf("instruction pointer = 0x%x:0x%x\n", 971 frame->tf_cs & 0xffff, frame->tf_eip); 972 if (TF_HAS_STACKREGS(frame)) { 973 ss = frame->tf_ss & 0xffff; 974 esp = frame->tf_esp; 975 } else { 976 ss = GSEL(GDATA_SEL, SEL_KPL); 977 esp = (int)&frame->tf_esp; 978 } 979 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 980 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 981 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 982 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 983 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 984 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 985 softseg.ssd_gran); 986 printf("processor eflags = "); 987 if (frame->tf_eflags & PSL_T) 988 printf("trace trap, "); 989 if (frame->tf_eflags & PSL_I) 990 printf("interrupt enabled, "); 991 if (frame->tf_eflags & PSL_NT) 992 printf("nested task, "); 993 if (frame->tf_eflags & PSL_RF) 994 printf("resume, "); 995 if (frame->tf_eflags & PSL_VM) 996 printf("vm86, "); 997 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 998 printf("current process = %d (%s)\n", 999 curproc->p_pid, curthread->td_name); 1000 1001#ifdef KDB 1002 if (debugger_on_panic || kdb_active) { 1003 frame->tf_err = eva; /* smuggle fault address to ddb */ 1004 if (kdb_trap(type, 0, frame)) { 1005 frame->tf_err = code; /* restore error code */ 1006 return; 1007 } 1008 frame->tf_err = code; /* restore error code */ 1009 } 1010#endif 1011 printf("trap number = %d\n", type); 1012 if (type <= MAX_TRAP_MSG) 1013 panic("%s", trap_msg[type]); 1014 else 1015 panic("unknown/reserved trap"); 1016} 1017 1018/* 1019 * Double fault handler. Called when a fault occurs while writing 1020 * a frame for a trap/exception onto the stack. This usually occurs 1021 * when the stack overflows (such is the case with infinite recursion, 1022 * for example). 1023 * 1024 * XXX Note that the current PTD gets replaced by IdlePTD when the 1025 * task switch occurs. This means that the stack that was active at 1026 * the time of the double fault is not available at <kstack> unless 1027 * the machine was idle when the double fault occurred. The downside 1028 * of this is that "trace <ebp>" in ddb won't work. 1029 */ 1030void 1031dblfault_handler() 1032{ 1033#ifdef KDTRACE_HOOKS 1034 if (dtrace_doubletrap_func != NULL) 1035 (*dtrace_doubletrap_func)(); 1036#endif 1037 printf("\nFatal double fault:\n"); 1038 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 1039 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 1040 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 1041#ifdef SMP 1042 /* two separate prints in case of a trap on an unmapped page */ 1043 printf("cpuid = %d; ", PCPU_GET(cpuid)); 1044 printf("apic id = %02x\n", PCPU_GET(apic_id)); 1045#endif 1046 panic("double fault"); 1047} 1048 1049int 1050cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 1051{ 1052 struct proc *p; 1053 struct trapframe *frame; 1054 caddr_t params; 1055 long tmp; 1056 int error; 1057 1058 p = td->td_proc; 1059 frame = td->td_frame; 1060 1061 params = (caddr_t)frame->tf_esp + sizeof(int); 1062 sa->code = frame->tf_eax; 1063 1064 /* 1065 * Need to check if this is a 32 bit or 64 bit syscall. 1066 */ 1067 if (sa->code == SYS_syscall) { 1068 /* 1069 * Code is first argument, followed by actual args. 1070 */ 1071 error = fueword(params, &tmp); 1072 if (error == -1) 1073 return (EFAULT); 1074 sa->code = tmp; 1075 params += sizeof(int); 1076 } else if (sa->code == SYS___syscall) { 1077 /* 1078 * Like syscall, but code is a quad, so as to maintain 1079 * quad alignment for the rest of the arguments. 1080 */ 1081 error = fueword(params, &tmp); 1082 if (error == -1) 1083 return (EFAULT); 1084 sa->code = tmp; 1085 params += sizeof(quad_t); 1086 } 1087 1088 if (p->p_sysent->sv_mask) 1089 sa->code &= p->p_sysent->sv_mask; 1090 if (sa->code >= p->p_sysent->sv_size) 1091 sa->callp = &p->p_sysent->sv_table[0]; 1092 else 1093 sa->callp = &p->p_sysent->sv_table[sa->code]; 1094 sa->narg = sa->callp->sy_narg; 1095 1096 if (params != NULL && sa->narg != 0) 1097 error = copyin(params, (caddr_t)sa->args, 1098 (u_int)(sa->narg * sizeof(int))); 1099 else 1100 error = 0; 1101 1102 if (error == 0) { 1103 td->td_retval[0] = 0; 1104 td->td_retval[1] = frame->tf_edx; 1105 } 1106 1107 return (error); 1108} 1109 1110#include "../../kern/subr_syscall.c" 1111 1112/* 1113 * syscall - system call request C handler. A system call is 1114 * essentially treated as a trap by reusing the frame layout. 1115 */ 1116void 1117syscall(struct trapframe *frame) 1118{ 1119 struct thread *td; 1120 struct syscall_args sa; 1121 register_t orig_tf_eflags; 1122 int error; 1123 ksiginfo_t ksi; 1124 1125#ifdef DIAGNOSTIC 1126 if (!(TRAPF_USERMODE(frame) && 1127 (curpcb->pcb_flags & PCB_VM86CALL) == 0)) { 1128 panic("syscall"); 1129 /* NOT REACHED */ 1130 } 1131#endif 1132 orig_tf_eflags = frame->tf_eflags; 1133 1134 td = curthread; 1135 td->td_frame = frame; 1136 1137 error = syscallenter(td, &sa); 1138 1139 /* 1140 * Traced syscall. 1141 */ 1142 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { 1143 frame->tf_eflags &= ~PSL_T; 1144 ksiginfo_init_trap(&ksi); 1145 ksi.ksi_signo = SIGTRAP; 1146 ksi.ksi_code = TRAP_TRACE; 1147 ksi.ksi_addr = (void *)frame->tf_eip; 1148 trapsignal(td, &ksi); 1149 } 1150 1151 KASSERT(PCB_USER_FPU(td->td_pcb), 1152 ("System call %s returning with kernel FPU ctx leaked", 1153 syscallname(td->td_proc, sa.code))); 1154 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td), 1155 ("System call %s returning with mangled pcb_save", 1156 syscallname(td->td_proc, sa.code))); 1157 1158 syscallret(td, error, &sa); 1159} 1160