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/11.0/sys/i386/i386/trap.c 287645 2015-09-11 03:54:37Z markj $"); 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> 76 PMC_SOFT_DEFINE( , , page_fault, all); 77 PMC_SOFT_DEFINE( , , page_fault, read); 78 PMC_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 110 111 extern void trap(struct trapframe *frame); 112 extern void syscall(struct trapframe *frame); 113 114 static int trap_pfault(struct trapframe *, int, vm_offset_t); 115 static void trap_fatal(struct trapframe *, vm_offset_t); 116 void dblfault_handler(void); 117 118 extern inthand_t IDTVEC(lcall_syscall); 119 120 #define MAX_TRAP_MSG 32 121 static 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) 158 int has_f00f_bug = 0; /* Initialized so that it can be patched. */ 159 #endif 160 161 #ifdef KDB 162 static int kdb_on_nmi = 1; 163 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RWTUN, 164 &kdb_on_nmi, 0, "Go to KDB on NMI"); 165 #endif 166 static int panic_on_nmi = 1; 167 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RWTUN, 168 &panic_on_nmi, 0, "Panic on NMI"); 169 static int prot_fault_translation = 0; 170 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 171 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 172 static int uprintf_signal; 173 SYSCTL_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 */ 183 184 void 185 trap(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 int i = 0, ucode = 0, code; 193 u_int type; 194 register_t addr = 0; 195 vm_offset_t eva; 196 ksiginfo_t ksi; 197 #ifdef POWERFAIL_NMI 198 static int lastalert = 0; 199 #endif 200 201 PCPU_INC(cnt.v_trap); 202 type = frame->tf_trapno; 203 204 #ifdef SMP 205 /* Handler for NMI IPIs used for stopping CPUs. */ 206 if (type == T_NMI) { 207 if (ipi_nmi_handler() == 0) 208 goto out; 209 } 210 #endif /* SMP */ 211 212 #ifdef KDB 213 if (kdb_active) { 214 kdb_reenter(); 215 goto out; 216 } 217 #endif 218 219 if (type == T_RESERVED) { 220 trap_fatal(frame, 0); 221 goto out; 222 } 223 224 if (type == T_NMI) { 225 #ifdef HWPMC_HOOKS 226 /* 227 * CPU PMCs interrupt using an NMI so we check for that first. 228 * If the HWPMC module is active, 'pmc_hook' will point to 229 * the function to be called. A non-zero return value from the 230 * hook means that the NMI was consumed by it and that we can 231 * return immediately. 232 */ 233 if (pmc_intr != NULL && 234 (*pmc_intr)(PCPU_GET(cpuid), frame) != 0) 235 goto out; 236 #endif 237 238 #ifdef STACK 239 if (stack_nmi_handler(frame) != 0) 240 goto out; 241 #endif 242 } 243 244 if (type == T_MCHK) { 245 mca_intr(); 246 goto out; 247 } 248 249 #ifdef KDTRACE_HOOKS 250 /* 251 * A trap can occur while DTrace executes a probe. Before 252 * executing the probe, DTrace blocks re-scheduling and sets 253 * a flag in its per-cpu flags to indicate that it doesn't 254 * want to fault. On returning from the probe, the no-fault 255 * flag is cleared and finally re-scheduling is enabled. 256 */ 257 if ((type == T_PROTFLT || type == T_PAGEFLT) && 258 dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type)) 259 goto out; 260 #endif 261 262 if ((frame->tf_eflags & PSL_I) == 0) { 263 /* 264 * Buggy application or kernel code has disabled 265 * interrupts and then trapped. Enabling interrupts 266 * now is wrong, but it is better than running with 267 * interrupts disabled until they are accidentally 268 * enabled later. 269 */ 270 if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM)) 271 uprintf( 272 "pid %ld (%s): trap %d with interrupts disabled\n", 273 (long)curproc->p_pid, curthread->td_name, type); 274 else if (type != T_NMI && type != T_BPTFLT && 275 type != T_TRCTRAP && 276 frame->tf_eip != (int)cpu_switch_load_gs) { 277 /* 278 * XXX not quite right, since this may be for a 279 * multiple fault in user mode. 280 */ 281 printf("kernel trap %d with interrupts disabled\n", 282 type); 283 /* 284 * Page faults need interrupts disabled until later, 285 * and we shouldn't enable interrupts while holding 286 * a spin lock. 287 */ 288 if (type != T_PAGEFLT && 289 td->td_md.md_spinlock_count == 0) 290 enable_intr(); 291 } 292 } 293 eva = 0; 294 code = frame->tf_err; 295 if (type == T_PAGEFLT) { 296 /* 297 * For some Cyrix CPUs, %cr2 is clobbered by 298 * interrupts. This problem is worked around by using 299 * an interrupt gate for the pagefault handler. We 300 * are finally ready to read %cr2 and conditionally 301 * reenable interrupts. If we hold a spin lock, then 302 * we must not reenable interrupts. This might be a 303 * spurious page fault. 304 */ 305 eva = rcr2(); 306 if (td->td_md.md_spinlock_count == 0) 307 enable_intr(); 308 } 309 310 if ((ISPL(frame->tf_cs) == SEL_UPL) || 311 ((frame->tf_eflags & PSL_VM) && 312 !(curpcb->pcb_flags & PCB_VM86CALL))) { 313 /* user trap */ 314 315 td->td_pticks = 0; 316 td->td_frame = frame; 317 addr = frame->tf_eip; 318 if (td->td_cowgen != p->p_cowgen) 319 thread_cow_update(td); 320 321 switch (type) { 322 case T_PRIVINFLT: /* privileged instruction fault */ 323 i = SIGILL; 324 ucode = ILL_PRVOPC; 325 break; 326 327 case T_BPTFLT: /* bpt instruction fault */ 328 case T_TRCTRAP: /* trace trap */ 329 enable_intr(); 330 #ifdef KDTRACE_HOOKS 331 if (type == T_BPTFLT) { 332 fill_frame_regs(frame, ®s); 333 if (dtrace_pid_probe_ptr != NULL && 334 dtrace_pid_probe_ptr(®s) == 0) 335 goto out; 336 } 337 #endif 338 frame->tf_eflags &= ~PSL_T; 339 i = SIGTRAP; 340 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 341 break; 342 343 case T_ARITHTRAP: /* arithmetic trap */ 344 #ifdef DEV_NPX 345 ucode = npxtrap_x87(); 346 if (ucode == -1) 347 goto userout; 348 #else 349 ucode = 0; 350 #endif 351 i = SIGFPE; 352 break; 353 354 /* 355 * The following two traps can happen in 356 * vm86 mode, and, if so, we want to handle 357 * them specially. 358 */ 359 case T_PROTFLT: /* general protection fault */ 360 case T_STKFLT: /* stack fault */ 361 if (frame->tf_eflags & PSL_VM) { 362 i = vm86_emulate((struct vm86frame *)frame); 363 if (i == 0) 364 goto user; 365 break; 366 } 367 i = SIGBUS; 368 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; 369 break; 370 case T_SEGNPFLT: /* segment not present fault */ 371 i = SIGBUS; 372 ucode = BUS_ADRERR; 373 break; 374 case T_TSSFLT: /* invalid TSS fault */ 375 i = SIGBUS; 376 ucode = BUS_OBJERR; 377 break; 378 case T_ALIGNFLT: 379 i = SIGBUS; 380 ucode = BUS_ADRALN; 381 break; 382 case T_DOUBLEFLT: /* double fault */ 383 default: 384 i = SIGBUS; 385 ucode = BUS_OBJERR; 386 break; 387 388 case T_PAGEFLT: /* page fault */ 389 390 i = trap_pfault(frame, TRUE, eva); 391 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 392 if (i == -2) { 393 /* 394 * The f00f hack workaround has triggered, so 395 * treat the fault as an illegal instruction 396 * (T_PRIVINFLT) instead of a page fault. 397 */ 398 type = frame->tf_trapno = T_PRIVINFLT; 399 400 /* Proceed as in that case. */ 401 ucode = ILL_PRVOPC; 402 i = SIGILL; 403 break; 404 } 405 #endif 406 if (i == -1) 407 goto userout; 408 if (i == 0) 409 goto user; 410 411 if (i == SIGSEGV) 412 ucode = SEGV_MAPERR; 413 else { 414 if (prot_fault_translation == 0) { 415 /* 416 * Autodetect. 417 * This check also covers the images 418 * without the ABI-tag ELF note. 419 */ 420 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 421 && p->p_osrel >= P_OSREL_SIGSEGV) { 422 i = SIGSEGV; 423 ucode = SEGV_ACCERR; 424 } else { 425 i = SIGBUS; 426 ucode = BUS_PAGE_FAULT; 427 } 428 } else if (prot_fault_translation == 1) { 429 /* 430 * Always compat mode. 431 */ 432 i = SIGBUS; 433 ucode = BUS_PAGE_FAULT; 434 } else { 435 /* 436 * Always SIGSEGV mode. 437 */ 438 i = SIGSEGV; 439 ucode = SEGV_ACCERR; 440 } 441 } 442 addr = eva; 443 break; 444 445 case T_DIVIDE: /* integer divide fault */ 446 ucode = FPE_INTDIV; 447 i = SIGFPE; 448 break; 449 450 #ifdef DEV_ISA 451 case T_NMI: 452 #ifdef POWERFAIL_NMI 453 #ifndef TIMER_FREQ 454 # define TIMER_FREQ 1193182 455 #endif 456 if (time_second - lastalert > 10) { 457 log(LOG_WARNING, "NMI: power fail\n"); 458 sysbeep(880, hz); 459 lastalert = time_second; 460 } 461 goto userout; 462 #else /* !POWERFAIL_NMI */ 463 /* machine/parity/power fail/"kitchen sink" faults */ 464 if (isa_nmi(code) == 0) { 465 #ifdef KDB 466 /* 467 * NMI can be hooked up to a pushbutton 468 * for debugging. 469 */ 470 if (kdb_on_nmi) { 471 printf ("NMI ... going to debugger\n"); 472 kdb_trap(type, 0, frame); 473 } 474 #endif /* KDB */ 475 goto userout; 476 } else if (panic_on_nmi) 477 panic("NMI indicates hardware failure"); 478 break; 479 #endif /* POWERFAIL_NMI */ 480 #endif /* DEV_ISA */ 481 482 case T_OFLOW: /* integer overflow fault */ 483 ucode = FPE_INTOVF; 484 i = SIGFPE; 485 break; 486 487 case T_BOUND: /* bounds check fault */ 488 ucode = FPE_FLTSUB; 489 i = SIGFPE; 490 break; 491 492 case T_DNA: 493 #ifdef DEV_NPX 494 KASSERT(PCB_USER_FPU(td->td_pcb), 495 ("kernel FPU ctx has leaked")); 496 /* transparent fault (due to context switch "late") */ 497 if (npxdna()) 498 goto userout; 499 #endif 500 uprintf("pid %d killed due to lack of floating point\n", 501 p->p_pid); 502 i = SIGKILL; 503 ucode = 0; 504 break; 505 506 case T_FPOPFLT: /* FPU operand fetch fault */ 507 ucode = ILL_COPROC; 508 i = SIGILL; 509 break; 510 511 case T_XMMFLT: /* SIMD floating-point exception */ 512 #if defined(DEV_NPX) && !defined(CPU_DISABLE_SSE) && defined(I686_CPU) 513 ucode = npxtrap_sse(); 514 if (ucode == -1) 515 goto userout; 516 #else 517 ucode = 0; 518 #endif 519 i = SIGFPE; 520 break; 521 #ifdef KDTRACE_HOOKS 522 case T_DTRACE_RET: 523 enable_intr(); 524 fill_frame_regs(frame, ®s); 525 if (dtrace_return_probe_ptr != NULL && 526 dtrace_return_probe_ptr(®s) == 0) 527 goto out; 528 break; 529 #endif 530 } 531 } else { 532 /* kernel trap */ 533 534 KASSERT(cold || td->td_ucred != NULL, 535 ("kernel trap doesn't have ucred")); 536 switch (type) { 537 case T_PAGEFLT: /* page fault */ 538 (void) trap_pfault(frame, FALSE, eva); 539 goto out; 540 541 case T_DNA: 542 #ifdef DEV_NPX 543 KASSERT(!PCB_USER_FPU(td->td_pcb), 544 ("Unregistered use of FPU in kernel")); 545 if (npxdna()) 546 goto out; 547 #endif 548 break; 549 550 case T_ARITHTRAP: /* arithmetic trap */ 551 case T_XMMFLT: /* SIMD floating-point exception */ 552 case T_FPOPFLT: /* FPU operand fetch fault */ 553 /* 554 * XXXKIB for now disable any FPU traps in kernel 555 * handler registration seems to be overkill 556 */ 557 trap_fatal(frame, 0); 558 goto out; 559 560 /* 561 * The following two traps can happen in 562 * vm86 mode, and, if so, we want to handle 563 * them specially. 564 */ 565 case T_PROTFLT: /* general protection fault */ 566 case T_STKFLT: /* stack fault */ 567 if (frame->tf_eflags & PSL_VM) { 568 i = vm86_emulate((struct vm86frame *)frame); 569 if (i != 0) 570 /* 571 * returns to original process 572 */ 573 vm86_trap((struct vm86frame *)frame); 574 goto out; 575 } 576 if (type == T_STKFLT) 577 break; 578 579 /* FALL THROUGH */ 580 581 case T_SEGNPFLT: /* segment not present fault */ 582 if (curpcb->pcb_flags & PCB_VM86CALL) 583 break; 584 585 /* 586 * Invalid %fs's and %gs's can be created using 587 * procfs or PT_SETREGS or by invalidating the 588 * underlying LDT entry. This causes a fault 589 * in kernel mode when the kernel attempts to 590 * switch contexts. Lose the bad context 591 * (XXX) so that we can continue, and generate 592 * a signal. 593 */ 594 if (frame->tf_eip == (int)cpu_switch_load_gs) { 595 curpcb->pcb_gs = 0; 596 #if 0 597 PROC_LOCK(p); 598 kern_psignal(p, SIGBUS); 599 PROC_UNLOCK(p); 600 #endif 601 goto out; 602 } 603 604 if (td->td_intr_nesting_level != 0) 605 break; 606 607 /* 608 * Invalid segment selectors and out of bounds 609 * %eip's and %esp's can be set up in user mode. 610 * This causes a fault in kernel mode when the 611 * kernel tries to return to user mode. We want 612 * to get this fault so that we can fix the 613 * problem here and not have to check all the 614 * selectors and pointers when the user changes 615 * them. 616 */ 617 if (frame->tf_eip == (int)doreti_iret) { 618 frame->tf_eip = (int)doreti_iret_fault; 619 goto out; 620 } 621 if (frame->tf_eip == (int)doreti_popl_ds) { 622 frame->tf_eip = (int)doreti_popl_ds_fault; 623 goto out; 624 } 625 if (frame->tf_eip == (int)doreti_popl_es) { 626 frame->tf_eip = (int)doreti_popl_es_fault; 627 goto out; 628 } 629 if (frame->tf_eip == (int)doreti_popl_fs) { 630 frame->tf_eip = (int)doreti_popl_fs_fault; 631 goto out; 632 } 633 if (curpcb->pcb_onfault != NULL) { 634 frame->tf_eip = 635 (int)curpcb->pcb_onfault; 636 goto out; 637 } 638 break; 639 640 case T_TSSFLT: 641 /* 642 * PSL_NT can be set in user mode and isn't cleared 643 * automatically when the kernel is entered. This 644 * causes a TSS fault when the kernel attempts to 645 * `iret' because the TSS link is uninitialized. We 646 * want to get this fault so that we can fix the 647 * problem here and not every time the kernel is 648 * entered. 649 */ 650 if (frame->tf_eflags & PSL_NT) { 651 frame->tf_eflags &= ~PSL_NT; 652 goto out; 653 } 654 break; 655 656 case T_TRCTRAP: /* trace trap */ 657 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) { 658 /* 659 * We've just entered system mode via the 660 * syscall lcall. Continue single stepping 661 * silently until the syscall handler has 662 * saved the flags. 663 */ 664 goto out; 665 } 666 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 667 /* 668 * The syscall handler has now saved the 669 * flags. Stop single stepping it. 670 */ 671 frame->tf_eflags &= ~PSL_T; 672 goto out; 673 } 674 /* 675 * Ignore debug register trace traps due to 676 * accesses in the user's address space, which 677 * can happen under several conditions such as 678 * if a user sets a watchpoint on a buffer and 679 * then passes that buffer to a system call. 680 * We still want to get TRCTRAPS for addresses 681 * in kernel space because that is useful when 682 * debugging the kernel. 683 */ 684 if (user_dbreg_trap() && 685 !(curpcb->pcb_flags & PCB_VM86CALL)) { 686 /* 687 * Reset breakpoint bits because the 688 * processor doesn't 689 */ 690 load_dr6(rdr6() & 0xfffffff0); 691 goto out; 692 } 693 /* 694 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 695 */ 696 case T_BPTFLT: 697 /* 698 * If KDB is enabled, let it handle the debugger trap. 699 * Otherwise, debugger traps "can't happen". 700 */ 701 #ifdef KDB 702 if (kdb_trap(type, 0, frame)) 703 goto out; 704 #endif 705 break; 706 707 #ifdef DEV_ISA 708 case T_NMI: 709 #ifdef POWERFAIL_NMI 710 if (time_second - lastalert > 10) { 711 log(LOG_WARNING, "NMI: power fail\n"); 712 sysbeep(880, hz); 713 lastalert = time_second; 714 } 715 goto out; 716 #else /* !POWERFAIL_NMI */ 717 /* machine/parity/power fail/"kitchen sink" faults */ 718 if (isa_nmi(code) == 0) { 719 #ifdef KDB 720 /* 721 * NMI can be hooked up to a pushbutton 722 * for debugging. 723 */ 724 if (kdb_on_nmi) { 725 printf ("NMI ... going to debugger\n"); 726 kdb_trap(type, 0, frame); 727 } 728 #endif /* KDB */ 729 goto out; 730 } else if (panic_on_nmi == 0) 731 goto out; 732 /* FALLTHROUGH */ 733 #endif /* POWERFAIL_NMI */ 734 #endif /* DEV_ISA */ 735 } 736 737 trap_fatal(frame, eva); 738 goto out; 739 } 740 741 /* Translate fault for emulators (e.g. Linux) */ 742 if (*p->p_sysent->sv_transtrap) 743 i = (*p->p_sysent->sv_transtrap)(i, type); 744 745 ksiginfo_init_trap(&ksi); 746 ksi.ksi_signo = i; 747 ksi.ksi_code = ucode; 748 ksi.ksi_addr = (void *)addr; 749 ksi.ksi_trapno = type; 750 if (uprintf_signal) { 751 uprintf("pid %d comm %s: signal %d err %x code %d type %d " 752 "addr 0x%x esp 0x%08x eip 0x%08x " 753 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 754 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 755 frame->tf_esp, frame->tf_eip, 756 fubyte((void *)(frame->tf_eip + 0)), 757 fubyte((void *)(frame->tf_eip + 1)), 758 fubyte((void *)(frame->tf_eip + 2)), 759 fubyte((void *)(frame->tf_eip + 3)), 760 fubyte((void *)(frame->tf_eip + 4)), 761 fubyte((void *)(frame->tf_eip + 5)), 762 fubyte((void *)(frame->tf_eip + 6)), 763 fubyte((void *)(frame->tf_eip + 7))); 764 } 765 KASSERT((read_eflags() & PSL_I) != 0, ("interrupts disabled")); 766 trapsignal(td, &ksi); 767 768 #ifdef DEBUG 769 if (type <= MAX_TRAP_MSG) { 770 uprintf("fatal process exception: %s", 771 trap_msg[type]); 772 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 773 uprintf(", fault VA = 0x%lx", (u_long)eva); 774 uprintf("\n"); 775 } 776 #endif 777 778 user: 779 userret(td, frame); 780 KASSERT(PCB_USER_FPU(td->td_pcb), 781 ("Return from trap with kernel FPU ctx leaked")); 782 userout: 783 out: 784 return; 785 } 786 787 static int 788 trap_pfault(frame, usermode, eva) 789 struct trapframe *frame; 790 int usermode; 791 vm_offset_t eva; 792 { 793 vm_offset_t va; 794 vm_map_t map; 795 int rv = 0; 796 vm_prot_t ftype; 797 struct thread *td = curthread; 798 struct proc *p = td->td_proc; 799 800 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 801 /* 802 * Due to both processor errata and lazy TLB invalidation when 803 * access restrictions are removed from virtual pages, memory 804 * accesses that are allowed by the physical mapping layer may 805 * nonetheless cause one spurious page fault per virtual page. 806 * When the thread is executing a "no faulting" section that 807 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 808 * every page fault is treated as a spurious page fault, 809 * unless it accesses the same virtual address as the most 810 * recent page fault within the same "no faulting" section. 811 */ 812 if (td->td_md.md_spurflt_addr != eva || 813 (td->td_pflags & TDP_RESETSPUR) != 0) { 814 /* 815 * Do nothing to the TLB. A stale TLB entry is 816 * flushed automatically by a page fault. 817 */ 818 td->td_md.md_spurflt_addr = eva; 819 td->td_pflags &= ~TDP_RESETSPUR; 820 return (0); 821 } 822 } else { 823 /* 824 * If we get a page fault while in a critical section, then 825 * it is most likely a fatal kernel page fault. The kernel 826 * is already going to panic trying to get a sleep lock to 827 * do the VM lookup, so just consider it a fatal trap so the 828 * kernel can print out a useful trap message and even get 829 * to the debugger. 830 * 831 * If we get a page fault while holding a non-sleepable 832 * lock, then it is most likely a fatal kernel page fault. 833 * If WITNESS is enabled, then it's going to whine about 834 * bogus LORs with various VM locks, so just skip to the 835 * fatal trap handling directly. 836 */ 837 if (td->td_critnest != 0 || 838 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 839 "Kernel page fault") != 0) { 840 trap_fatal(frame, eva); 841 return (-1); 842 } 843 } 844 va = trunc_page(eva); 845 if (va >= KERNBASE) { 846 /* 847 * Don't allow user-mode faults in kernel address space. 848 * An exception: if the faulting address is the invalid 849 * instruction entry in the IDT, then the Intel Pentium 850 * F00F bug workaround was triggered, and we need to 851 * treat it is as an illegal instruction, and not a page 852 * fault. 853 */ 854 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 855 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) 856 return (-2); 857 #endif 858 if (usermode) 859 goto nogo; 860 861 map = kernel_map; 862 } else { 863 map = &p->p_vmspace->vm_map; 864 865 /* 866 * When accessing a user-space address, kernel must be 867 * ready to accept the page fault, and provide a 868 * handling routine. Since accessing the address 869 * without the handler is a bug, do not try to handle 870 * it normally, and panic immediately. 871 */ 872 if (!usermode && (td->td_intr_nesting_level != 0 || 873 curpcb->pcb_onfault == NULL)) { 874 trap_fatal(frame, eva); 875 return (-1); 876 } 877 } 878 879 /* 880 * PGEX_I is defined only if the execute disable bit capability is 881 * supported and enabled. 882 */ 883 if (frame->tf_err & PGEX_W) 884 ftype = VM_PROT_WRITE; 885 #if defined(PAE) || defined(PAE_TABLES) 886 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 887 ftype = VM_PROT_EXECUTE; 888 #endif 889 else 890 ftype = VM_PROT_READ; 891 892 /* Fault in the page. */ 893 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 894 if (rv == KERN_SUCCESS) { 895 #ifdef HWPMC_HOOKS 896 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 897 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 898 if (ftype == VM_PROT_READ) 899 PMC_SOFT_CALL_TF( , , page_fault, read, 900 frame); 901 else 902 PMC_SOFT_CALL_TF( , , page_fault, write, 903 frame); 904 } 905 #endif 906 return (0); 907 } 908 nogo: 909 if (!usermode) { 910 if (td->td_intr_nesting_level == 0 && 911 curpcb->pcb_onfault != NULL) { 912 frame->tf_eip = (int)curpcb->pcb_onfault; 913 return (0); 914 } 915 trap_fatal(frame, eva); 916 return (-1); 917 } 918 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 919 } 920 921 static void 922 trap_fatal(frame, eva) 923 struct trapframe *frame; 924 vm_offset_t eva; 925 { 926 int code, ss, esp; 927 u_int type; 928 struct soft_segment_descriptor softseg; 929 char *msg; 930 931 code = frame->tf_err; 932 type = frame->tf_trapno; 933 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 934 935 if (type <= MAX_TRAP_MSG) 936 msg = trap_msg[type]; 937 else 938 msg = "UNKNOWN"; 939 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 940 frame->tf_eflags & PSL_VM ? "vm86" : 941 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 942 #ifdef SMP 943 /* two separate prints in case of a trap on an unmapped page */ 944 printf("cpuid = %d; ", PCPU_GET(cpuid)); 945 printf("apic id = %02x\n", PCPU_GET(apic_id)); 946 #endif 947 if (type == T_PAGEFLT) { 948 printf("fault virtual address = 0x%x\n", eva); 949 printf("fault code = %s %s, %s\n", 950 code & PGEX_U ? "user" : "supervisor", 951 code & PGEX_W ? "write" : "read", 952 code & PGEX_P ? "protection violation" : "page not present"); 953 } 954 printf("instruction pointer = 0x%x:0x%x\n", 955 frame->tf_cs & 0xffff, frame->tf_eip); 956 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 957 ss = frame->tf_ss & 0xffff; 958 esp = frame->tf_esp; 959 } else { 960 ss = GSEL(GDATA_SEL, SEL_KPL); 961 esp = (int)&frame->tf_esp; 962 } 963 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 964 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 965 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 966 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 967 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 968 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 969 softseg.ssd_gran); 970 printf("processor eflags = "); 971 if (frame->tf_eflags & PSL_T) 972 printf("trace trap, "); 973 if (frame->tf_eflags & PSL_I) 974 printf("interrupt enabled, "); 975 if (frame->tf_eflags & PSL_NT) 976 printf("nested task, "); 977 if (frame->tf_eflags & PSL_RF) 978 printf("resume, "); 979 if (frame->tf_eflags & PSL_VM) 980 printf("vm86, "); 981 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 982 printf("current process = %d (%s)\n", 983 curproc->p_pid, curthread->td_name); 984 985 #ifdef KDB 986 if (debugger_on_panic || kdb_active) { 987 frame->tf_err = eva; /* smuggle fault address to ddb */ 988 if (kdb_trap(type, 0, frame)) { 989 frame->tf_err = code; /* restore error code */ 990 return; 991 } 992 frame->tf_err = code; /* restore error code */ 993 } 994 #endif 995 printf("trap number = %d\n", type); 996 if (type <= MAX_TRAP_MSG) 997 panic("%s", trap_msg[type]); 998 else 999 panic("unknown/reserved trap"); 1000 } 1001 1002 /* 1003 * Double fault handler. Called when a fault occurs while writing 1004 * a frame for a trap/exception onto the stack. This usually occurs 1005 * when the stack overflows (such is the case with infinite recursion, 1006 * for example). 1007 * 1008 * XXX Note that the current PTD gets replaced by IdlePTD when the 1009 * task switch occurs. This means that the stack that was active at 1010 * the time of the double fault is not available at <kstack> unless 1011 * the machine was idle when the double fault occurred. The downside 1012 * of this is that "trace <ebp>" in ddb won't work. 1013 */ 1014 void 1015 dblfault_handler() 1016 { 1017 #ifdef KDTRACE_HOOKS 1018 if (dtrace_doubletrap_func != NULL) 1019 (*dtrace_doubletrap_func)(); 1020 #endif 1021 printf("\nFatal double fault:\n"); 1022 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 1023 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 1024 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 1025 #ifdef SMP 1026 /* two separate prints in case of a trap on an unmapped page */ 1027 printf("cpuid = %d; ", PCPU_GET(cpuid)); 1028 printf("apic id = %02x\n", PCPU_GET(apic_id)); 1029 #endif 1030 panic("double fault"); 1031 } 1032 1033 int 1034 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 1035 { 1036 struct proc *p; 1037 struct trapframe *frame; 1038 caddr_t params; 1039 long tmp; 1040 int error; 1041 1042 p = td->td_proc; 1043 frame = td->td_frame; 1044 1045 params = (caddr_t)frame->tf_esp + sizeof(int); 1046 sa->code = frame->tf_eax; 1047 1048 /* 1049 * Need to check if this is a 32 bit or 64 bit syscall. 1050 */ 1051 if (sa->code == SYS_syscall) { 1052 /* 1053 * Code is first argument, followed by actual args. 1054 */ 1055 error = fueword(params, &tmp); 1056 if (error == -1) 1057 return (EFAULT); 1058 sa->code = tmp; 1059 params += sizeof(int); 1060 } else if (sa->code == SYS___syscall) { 1061 /* 1062 * Like syscall, but code is a quad, so as to maintain 1063 * quad alignment for the rest of the arguments. 1064 */ 1065 error = fueword(params, &tmp); 1066 if (error == -1) 1067 return (EFAULT); 1068 sa->code = tmp; 1069 params += sizeof(quad_t); 1070 } 1071 1072 if (p->p_sysent->sv_mask) 1073 sa->code &= p->p_sysent->sv_mask; 1074 if (sa->code >= p->p_sysent->sv_size) 1075 sa->callp = &p->p_sysent->sv_table[0]; 1076 else 1077 sa->callp = &p->p_sysent->sv_table[sa->code]; 1078 sa->narg = sa->callp->sy_narg; 1079 1080 if (params != NULL && sa->narg != 0) 1081 error = copyin(params, (caddr_t)sa->args, 1082 (u_int)(sa->narg * sizeof(int))); 1083 else 1084 error = 0; 1085 1086 if (error == 0) { 1087 td->td_retval[0] = 0; 1088 td->td_retval[1] = frame->tf_edx; 1089 } 1090 1091 return (error); 1092 } 1093 1094 #include "../../kern/subr_syscall.c" 1095 1096 /* 1097 * syscall - system call request C handler. A system call is 1098 * essentially treated as a trap by reusing the frame layout. 1099 */ 1100 void 1101 syscall(struct trapframe *frame) 1102 { 1103 struct thread *td; 1104 struct syscall_args sa; 1105 register_t orig_tf_eflags; 1106 int error; 1107 ksiginfo_t ksi; 1108 1109 #ifdef DIAGNOSTIC 1110 if (ISPL(frame->tf_cs) != SEL_UPL) { 1111 panic("syscall"); 1112 /* NOT REACHED */ 1113 } 1114 #endif 1115 orig_tf_eflags = frame->tf_eflags; 1116 1117 td = curthread; 1118 td->td_frame = frame; 1119 1120 error = syscallenter(td, &sa); 1121 1122 /* 1123 * Traced syscall. 1124 */ 1125 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { 1126 frame->tf_eflags &= ~PSL_T; 1127 ksiginfo_init_trap(&ksi); 1128 ksi.ksi_signo = SIGTRAP; 1129 ksi.ksi_code = TRAP_TRACE; 1130 ksi.ksi_addr = (void *)frame->tf_eip; 1131 trapsignal(td, &ksi); 1132 } 1133 1134 KASSERT(PCB_USER_FPU(td->td_pcb), 1135 ("System call %s returning with kernel FPU ctx leaked", 1136 syscallname(td->td_proc, sa.code))); 1137 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td), 1138 ("System call %s returning with mangled pcb_save", 1139 syscallname(td->td_proc, sa.code))); 1140 1141 syscallret(td, error, &sa); 1142 }
Cache object: d16e314a5b7a2d09525bfdcf6094fedb
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