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: releng/10.0/sys/i386/i386/trap.c 251324 2013-06-03 17:40:05Z kib $"); 42 43 /* 44 * 386 Trap and System call handling 45 */ 46 47 #include "opt_clock.h" 48 #include "opt_cpu.h" 49 #include "opt_hwpmc_hooks.h" 50 #include "opt_isa.h" 51 #include "opt_kdb.h" 52 #include "opt_kdtrace.h" 53 #include "opt_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 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/tss.h> 99 #include <machine/vm86.h> 100 101 #ifdef POWERFAIL_NMI 102 #include <sys/syslog.h> 103 #include <machine/clock.h> 104 #endif 105 106 #ifdef KDTRACE_HOOKS 107 #include <sys/dtrace_bsd.h> 108 109 /* 110 * This is a hook which is initialised by the dtrace module 111 * to handle traps which might occur during DTrace probe 112 * execution. 113 */ 114 dtrace_trap_func_t dtrace_trap_func; 115 116 dtrace_doubletrap_func_t dtrace_doubletrap_func; 117 118 /* 119 * This is a hook which is initialised by the systrace module 120 * when it is loaded. This keeps the DTrace syscall provider 121 * implementation opaque. 122 */ 123 systrace_probe_func_t systrace_probe_func; 124 125 /* 126 * These hooks are necessary for the pid, usdt and fasttrap providers. 127 */ 128 dtrace_fasttrap_probe_ptr_t dtrace_fasttrap_probe_ptr; 129 dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr; 130 dtrace_return_probe_ptr_t dtrace_return_probe_ptr; 131 #endif 132 133 extern void trap(struct trapframe *frame); 134 extern void syscall(struct trapframe *frame); 135 136 static int trap_pfault(struct trapframe *, int, vm_offset_t); 137 static void trap_fatal(struct trapframe *, vm_offset_t); 138 void dblfault_handler(void); 139 140 extern inthand_t IDTVEC(lcall_syscall); 141 142 #define MAX_TRAP_MSG 33 143 static char *trap_msg[] = { 144 "", /* 0 unused */ 145 "privileged instruction fault", /* 1 T_PRIVINFLT */ 146 "", /* 2 unused */ 147 "breakpoint instruction fault", /* 3 T_BPTFLT */ 148 "", /* 4 unused */ 149 "", /* 5 unused */ 150 "arithmetic trap", /* 6 T_ARITHTRAP */ 151 "", /* 7 unused */ 152 "", /* 8 unused */ 153 "general protection fault", /* 9 T_PROTFLT */ 154 "trace trap", /* 10 T_TRCTRAP */ 155 "", /* 11 unused */ 156 "page fault", /* 12 T_PAGEFLT */ 157 "", /* 13 unused */ 158 "alignment fault", /* 14 T_ALIGNFLT */ 159 "", /* 15 unused */ 160 "", /* 16 unused */ 161 "", /* 17 unused */ 162 "integer divide fault", /* 18 T_DIVIDE */ 163 "non-maskable interrupt trap", /* 19 T_NMI */ 164 "overflow trap", /* 20 T_OFLOW */ 165 "FPU bounds check fault", /* 21 T_BOUND */ 166 "FPU device not available", /* 22 T_DNA */ 167 "double fault", /* 23 T_DOUBLEFLT */ 168 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 169 "invalid TSS fault", /* 25 T_TSSFLT */ 170 "segment not present fault", /* 26 T_SEGNPFLT */ 171 "stack fault", /* 27 T_STKFLT */ 172 "machine check trap", /* 28 T_MCHK */ 173 "SIMD floating-point exception", /* 29 T_XMMFLT */ 174 "reserved (unknown) fault", /* 30 T_RESERVED */ 175 "", /* 31 unused (reserved) */ 176 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 177 "DTrace fasttrap probe trap", /* 33 T_DTRACE_PROBE */ 178 179 }; 180 181 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 182 extern int has_f00f_bug; 183 #endif 184 185 #ifdef KDB 186 static int kdb_on_nmi = 1; 187 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 188 &kdb_on_nmi, 0, "Go to KDB on NMI"); 189 TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi); 190 #endif 191 static int panic_on_nmi = 1; 192 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 193 &panic_on_nmi, 0, "Panic on NMI"); 194 TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi); 195 static int prot_fault_translation = 0; 196 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 197 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 198 static int uprintf_signal; 199 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW, 200 &uprintf_signal, 0, 201 "Print debugging information on trap signal to ctty"); 202 203 /* 204 * Exception, fault, and trap interface to the FreeBSD kernel. 205 * This common code is called from assembly language IDT gate entry 206 * routines that prepare a suitable stack frame, and restore this 207 * frame after the exception has been processed. 208 */ 209 210 void 211 trap(struct trapframe *frame) 212 { 213 struct thread *td = curthread; 214 struct proc *p = td->td_proc; 215 int i = 0, ucode = 0, code; 216 u_int type; 217 register_t addr = 0; 218 vm_offset_t eva; 219 ksiginfo_t ksi; 220 #ifdef POWERFAIL_NMI 221 static int lastalert = 0; 222 #endif 223 224 PCPU_INC(cnt.v_trap); 225 type = frame->tf_trapno; 226 227 #ifdef SMP 228 /* Handler for NMI IPIs used for stopping CPUs. */ 229 if (type == T_NMI) { 230 if (ipi_nmi_handler() == 0) 231 goto out; 232 } 233 #endif /* SMP */ 234 235 #ifdef KDB 236 if (kdb_active) { 237 kdb_reenter(); 238 goto out; 239 } 240 #endif 241 242 if (type == T_RESERVED) { 243 trap_fatal(frame, 0); 244 goto out; 245 } 246 247 #ifdef HWPMC_HOOKS 248 /* 249 * CPU PMCs interrupt using an NMI so we check for that first. 250 * If the HWPMC module is active, 'pmc_hook' will point to 251 * the function to be called. A return value of '1' from the 252 * hook means that the NMI was handled by it and that we can 253 * return immediately. 254 */ 255 if (type == T_NMI && pmc_intr && 256 (*pmc_intr)(PCPU_GET(cpuid), frame)) 257 goto out; 258 #endif 259 260 if (type == T_MCHK) { 261 mca_intr(); 262 goto out; 263 } 264 265 #ifdef KDTRACE_HOOKS 266 /* 267 * A trap can occur while DTrace executes a probe. Before 268 * executing the probe, DTrace blocks re-scheduling and sets 269 * a flag in it's per-cpu flags to indicate that it doesn't 270 * want to fault. On returning from the probe, the no-fault 271 * flag is cleared and finally re-scheduling is enabled. 272 * 273 * If the DTrace kernel module has registered a trap handler, 274 * call it and if it returns non-zero, assume that it has 275 * handled the trap and modified the trap frame so that this 276 * function can return normally. 277 */ 278 if (type == T_DTRACE_PROBE || type == T_DTRACE_RET || 279 type == T_BPTFLT) { 280 struct reg regs; 281 282 fill_frame_regs(frame, ®s); 283 if (type == T_DTRACE_PROBE && 284 dtrace_fasttrap_probe_ptr != NULL && 285 dtrace_fasttrap_probe_ptr(®s) == 0) 286 goto out; 287 if (type == T_BPTFLT && 288 dtrace_pid_probe_ptr != NULL && 289 dtrace_pid_probe_ptr(®s) == 0) 290 goto out; 291 if (type == T_DTRACE_RET && 292 dtrace_return_probe_ptr != NULL && 293 dtrace_return_probe_ptr(®s) == 0) 294 goto out; 295 } 296 if ((type == T_PROTFLT || type == T_PAGEFLT) && 297 dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type)) 298 goto out; 299 #endif 300 301 if ((frame->tf_eflags & PSL_I) == 0) { 302 /* 303 * Buggy application or kernel code has disabled 304 * interrupts and then trapped. Enabling interrupts 305 * now is wrong, but it is better than running with 306 * interrupts disabled until they are accidentally 307 * enabled later. 308 */ 309 if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM)) 310 uprintf( 311 "pid %ld (%s): trap %d with interrupts disabled\n", 312 (long)curproc->p_pid, curthread->td_name, type); 313 else if (type != T_NMI && type != T_BPTFLT && 314 type != T_TRCTRAP && 315 frame->tf_eip != (int)cpu_switch_load_gs) { 316 /* 317 * XXX not quite right, since this may be for a 318 * multiple fault in user mode. 319 */ 320 printf("kernel trap %d with interrupts disabled\n", 321 type); 322 /* 323 * Page faults need interrupts disabled until later, 324 * and we shouldn't enable interrupts while holding 325 * a spin lock. 326 */ 327 if (type != T_PAGEFLT && 328 td->td_md.md_spinlock_count == 0) 329 enable_intr(); 330 } 331 } 332 eva = 0; 333 code = frame->tf_err; 334 if (type == T_PAGEFLT) { 335 /* 336 * For some Cyrix CPUs, %cr2 is clobbered by 337 * interrupts. This problem is worked around by using 338 * an interrupt gate for the pagefault handler. We 339 * are finally ready to read %cr2 and conditionally 340 * reenable interrupts. If we hold a spin lock, then 341 * we must not reenable interrupts. This might be a 342 * spurious page fault. 343 */ 344 eva = rcr2(); 345 if (td->td_md.md_spinlock_count == 0) 346 enable_intr(); 347 } 348 349 if ((ISPL(frame->tf_cs) == SEL_UPL) || 350 ((frame->tf_eflags & PSL_VM) && 351 !(curpcb->pcb_flags & PCB_VM86CALL))) { 352 /* user trap */ 353 354 td->td_pticks = 0; 355 td->td_frame = frame; 356 addr = frame->tf_eip; 357 if (td->td_ucred != p->p_ucred) 358 cred_update_thread(td); 359 360 switch (type) { 361 case T_PRIVINFLT: /* privileged instruction fault */ 362 i = SIGILL; 363 ucode = ILL_PRVOPC; 364 break; 365 366 case T_BPTFLT: /* bpt instruction fault */ 367 case T_TRCTRAP: /* trace trap */ 368 enable_intr(); 369 frame->tf_eflags &= ~PSL_T; 370 i = SIGTRAP; 371 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 372 break; 373 374 case T_ARITHTRAP: /* arithmetic trap */ 375 #ifdef DEV_NPX 376 ucode = npxtrap_x87(); 377 if (ucode == -1) 378 goto userout; 379 #else 380 ucode = 0; 381 #endif 382 i = SIGFPE; 383 break; 384 385 /* 386 * The following two traps can happen in 387 * vm86 mode, and, if so, we want to handle 388 * them specially. 389 */ 390 case T_PROTFLT: /* general protection fault */ 391 case T_STKFLT: /* stack fault */ 392 if (frame->tf_eflags & PSL_VM) { 393 i = vm86_emulate((struct vm86frame *)frame); 394 if (i == 0) 395 goto user; 396 break; 397 } 398 i = SIGBUS; 399 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; 400 break; 401 case T_SEGNPFLT: /* segment not present fault */ 402 i = SIGBUS; 403 ucode = BUS_ADRERR; 404 break; 405 case T_TSSFLT: /* invalid TSS fault */ 406 i = SIGBUS; 407 ucode = BUS_OBJERR; 408 break; 409 case T_DOUBLEFLT: /* double fault */ 410 default: 411 i = SIGBUS; 412 ucode = BUS_OBJERR; 413 break; 414 415 case T_PAGEFLT: /* page fault */ 416 417 i = trap_pfault(frame, TRUE, eva); 418 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 419 if (i == -2) { 420 /* 421 * The f00f hack workaround has triggered, so 422 * treat the fault as an illegal instruction 423 * (T_PRIVINFLT) instead of a page fault. 424 */ 425 type = frame->tf_trapno = T_PRIVINFLT; 426 427 /* Proceed as in that case. */ 428 ucode = ILL_PRVOPC; 429 i = SIGILL; 430 break; 431 } 432 #endif 433 if (i == -1) 434 goto userout; 435 if (i == 0) 436 goto user; 437 438 if (i == SIGSEGV) 439 ucode = SEGV_MAPERR; 440 else { 441 if (prot_fault_translation == 0) { 442 /* 443 * Autodetect. 444 * This check also covers the images 445 * without the ABI-tag ELF note. 446 */ 447 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 448 && p->p_osrel >= P_OSREL_SIGSEGV) { 449 i = SIGSEGV; 450 ucode = SEGV_ACCERR; 451 } else { 452 i = SIGBUS; 453 ucode = BUS_PAGE_FAULT; 454 } 455 } else if (prot_fault_translation == 1) { 456 /* 457 * Always compat mode. 458 */ 459 i = SIGBUS; 460 ucode = BUS_PAGE_FAULT; 461 } else { 462 /* 463 * Always SIGSEGV mode. 464 */ 465 i = SIGSEGV; 466 ucode = SEGV_ACCERR; 467 } 468 } 469 addr = eva; 470 break; 471 472 case T_DIVIDE: /* integer divide fault */ 473 ucode = FPE_INTDIV; 474 i = SIGFPE; 475 break; 476 477 #ifdef DEV_ISA 478 case T_NMI: 479 #ifdef POWERFAIL_NMI 480 #ifndef TIMER_FREQ 481 # define TIMER_FREQ 1193182 482 #endif 483 if (time_second - lastalert > 10) { 484 log(LOG_WARNING, "NMI: power fail\n"); 485 sysbeep(880, hz); 486 lastalert = time_second; 487 } 488 goto userout; 489 #else /* !POWERFAIL_NMI */ 490 /* machine/parity/power fail/"kitchen sink" faults */ 491 if (isa_nmi(code) == 0) { 492 #ifdef KDB 493 /* 494 * NMI can be hooked up to a pushbutton 495 * for debugging. 496 */ 497 if (kdb_on_nmi) { 498 printf ("NMI ... going to debugger\n"); 499 kdb_trap(type, 0, frame); 500 } 501 #endif /* KDB */ 502 goto userout; 503 } else if (panic_on_nmi) 504 panic("NMI indicates hardware failure"); 505 break; 506 #endif /* POWERFAIL_NMI */ 507 #endif /* DEV_ISA */ 508 509 case T_OFLOW: /* integer overflow fault */ 510 ucode = FPE_INTOVF; 511 i = SIGFPE; 512 break; 513 514 case T_BOUND: /* bounds check fault */ 515 ucode = FPE_FLTSUB; 516 i = SIGFPE; 517 break; 518 519 case T_DNA: 520 #ifdef DEV_NPX 521 KASSERT(PCB_USER_FPU(td->td_pcb), 522 ("kernel FPU ctx has leaked")); 523 /* transparent fault (due to context switch "late") */ 524 if (npxdna()) 525 goto userout; 526 #endif 527 uprintf("pid %d killed due to lack of floating point\n", 528 p->p_pid); 529 i = SIGKILL; 530 ucode = 0; 531 break; 532 533 case T_FPOPFLT: /* FPU operand fetch fault */ 534 ucode = ILL_COPROC; 535 i = SIGILL; 536 break; 537 538 case T_XMMFLT: /* SIMD floating-point exception */ 539 #if defined(DEV_NPX) && !defined(CPU_DISABLE_SSE) && defined(I686_CPU) 540 ucode = npxtrap_sse(); 541 if (ucode == -1) 542 goto userout; 543 #else 544 ucode = 0; 545 #endif 546 i = SIGFPE; 547 break; 548 } 549 } else { 550 /* kernel trap */ 551 552 KASSERT(cold || td->td_ucred != NULL, 553 ("kernel trap doesn't have ucred")); 554 switch (type) { 555 case T_PAGEFLT: /* page fault */ 556 (void) trap_pfault(frame, FALSE, eva); 557 goto out; 558 559 case T_DNA: 560 #ifdef DEV_NPX 561 KASSERT(!PCB_USER_FPU(td->td_pcb), 562 ("Unregistered use of FPU in kernel")); 563 if (npxdna()) 564 goto out; 565 #endif 566 break; 567 568 case T_ARITHTRAP: /* arithmetic trap */ 569 case T_XMMFLT: /* SIMD floating-point exception */ 570 case T_FPOPFLT: /* FPU operand fetch fault */ 571 /* 572 * XXXKIB for now disable any FPU traps in kernel 573 * handler registration seems to be overkill 574 */ 575 trap_fatal(frame, 0); 576 goto out; 577 578 /* 579 * The following two traps can happen in 580 * vm86 mode, and, if so, we want to handle 581 * them specially. 582 */ 583 case T_PROTFLT: /* general protection fault */ 584 case T_STKFLT: /* stack fault */ 585 if (frame->tf_eflags & PSL_VM) { 586 i = vm86_emulate((struct vm86frame *)frame); 587 if (i != 0) 588 /* 589 * returns to original process 590 */ 591 vm86_trap((struct vm86frame *)frame); 592 goto out; 593 } 594 if (type == T_STKFLT) 595 break; 596 597 /* FALL THROUGH */ 598 599 case T_SEGNPFLT: /* segment not present fault */ 600 if (curpcb->pcb_flags & PCB_VM86CALL) 601 break; 602 603 /* 604 * Invalid %fs's and %gs's can be created using 605 * procfs or PT_SETREGS or by invalidating the 606 * underlying LDT entry. This causes a fault 607 * in kernel mode when the kernel attempts to 608 * switch contexts. Lose the bad context 609 * (XXX) so that we can continue, and generate 610 * a signal. 611 */ 612 if (frame->tf_eip == (int)cpu_switch_load_gs) { 613 curpcb->pcb_gs = 0; 614 #if 0 615 PROC_LOCK(p); 616 kern_psignal(p, SIGBUS); 617 PROC_UNLOCK(p); 618 #endif 619 goto out; 620 } 621 622 if (td->td_intr_nesting_level != 0) 623 break; 624 625 /* 626 * Invalid segment selectors and out of bounds 627 * %eip's and %esp's can be set up in user mode. 628 * This causes a fault in kernel mode when the 629 * kernel tries to return to user mode. We want 630 * to get this fault so that we can fix the 631 * problem here and not have to check all the 632 * selectors and pointers when the user changes 633 * them. 634 */ 635 if (frame->tf_eip == (int)doreti_iret) { 636 frame->tf_eip = (int)doreti_iret_fault; 637 goto out; 638 } 639 if (frame->tf_eip == (int)doreti_popl_ds) { 640 frame->tf_eip = (int)doreti_popl_ds_fault; 641 goto out; 642 } 643 if (frame->tf_eip == (int)doreti_popl_es) { 644 frame->tf_eip = (int)doreti_popl_es_fault; 645 goto out; 646 } 647 if (frame->tf_eip == (int)doreti_popl_fs) { 648 frame->tf_eip = (int)doreti_popl_fs_fault; 649 goto out; 650 } 651 if (curpcb->pcb_onfault != NULL) { 652 frame->tf_eip = 653 (int)curpcb->pcb_onfault; 654 goto out; 655 } 656 break; 657 658 case T_TSSFLT: 659 /* 660 * PSL_NT can be set in user mode and isn't cleared 661 * automatically when the kernel is entered. This 662 * causes a TSS fault when the kernel attempts to 663 * `iret' because the TSS link is uninitialized. We 664 * want to get this fault so that we can fix the 665 * problem here and not every time the kernel is 666 * entered. 667 */ 668 if (frame->tf_eflags & PSL_NT) { 669 frame->tf_eflags &= ~PSL_NT; 670 goto out; 671 } 672 break; 673 674 case T_TRCTRAP: /* trace trap */ 675 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) { 676 /* 677 * We've just entered system mode via the 678 * syscall lcall. Continue single stepping 679 * silently until the syscall handler has 680 * saved the flags. 681 */ 682 goto out; 683 } 684 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 685 /* 686 * The syscall handler has now saved the 687 * flags. Stop single stepping it. 688 */ 689 frame->tf_eflags &= ~PSL_T; 690 goto out; 691 } 692 /* 693 * Ignore debug register trace traps due to 694 * accesses in the user's address space, which 695 * can happen under several conditions such as 696 * if a user sets a watchpoint on a buffer and 697 * then passes that buffer to a system call. 698 * We still want to get TRCTRAPS for addresses 699 * in kernel space because that is useful when 700 * debugging the kernel. 701 */ 702 if (user_dbreg_trap() && 703 !(curpcb->pcb_flags & PCB_VM86CALL)) { 704 /* 705 * Reset breakpoint bits because the 706 * processor doesn't 707 */ 708 load_dr6(rdr6() & 0xfffffff0); 709 goto out; 710 } 711 /* 712 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 713 */ 714 case T_BPTFLT: 715 /* 716 * If KDB is enabled, let it handle the debugger trap. 717 * Otherwise, debugger traps "can't happen". 718 */ 719 #ifdef KDB 720 if (kdb_trap(type, 0, frame)) 721 goto out; 722 #endif 723 break; 724 725 #ifdef DEV_ISA 726 case T_NMI: 727 #ifdef POWERFAIL_NMI 728 if (time_second - lastalert > 10) { 729 log(LOG_WARNING, "NMI: power fail\n"); 730 sysbeep(880, hz); 731 lastalert = time_second; 732 } 733 goto out; 734 #else /* !POWERFAIL_NMI */ 735 /* machine/parity/power fail/"kitchen sink" faults */ 736 if (isa_nmi(code) == 0) { 737 #ifdef KDB 738 /* 739 * NMI can be hooked up to a pushbutton 740 * for debugging. 741 */ 742 if (kdb_on_nmi) { 743 printf ("NMI ... going to debugger\n"); 744 kdb_trap(type, 0, frame); 745 } 746 #endif /* KDB */ 747 goto out; 748 } else if (panic_on_nmi == 0) 749 goto out; 750 /* FALLTHROUGH */ 751 #endif /* POWERFAIL_NMI */ 752 #endif /* DEV_ISA */ 753 } 754 755 trap_fatal(frame, eva); 756 goto out; 757 } 758 759 /* Translate fault for emulators (e.g. Linux) */ 760 if (*p->p_sysent->sv_transtrap) 761 i = (*p->p_sysent->sv_transtrap)(i, type); 762 763 ksiginfo_init_trap(&ksi); 764 ksi.ksi_signo = i; 765 ksi.ksi_code = ucode; 766 ksi.ksi_addr = (void *)addr; 767 ksi.ksi_trapno = type; 768 if (uprintf_signal) { 769 uprintf("pid %d comm %s: signal %d err %x code %d type %d " 770 "addr 0x%x esp 0x%08x eip 0x%08x " 771 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 772 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 773 frame->tf_esp, frame->tf_eip, 774 fubyte((void *)(frame->tf_eip + 0)), 775 fubyte((void *)(frame->tf_eip + 1)), 776 fubyte((void *)(frame->tf_eip + 2)), 777 fubyte((void *)(frame->tf_eip + 3)), 778 fubyte((void *)(frame->tf_eip + 4)), 779 fubyte((void *)(frame->tf_eip + 5)), 780 fubyte((void *)(frame->tf_eip + 6)), 781 fubyte((void *)(frame->tf_eip + 7))); 782 } 783 KASSERT((read_eflags() & PSL_I) != 0, ("interrupts disabled")); 784 trapsignal(td, &ksi); 785 786 #ifdef DEBUG 787 if (type <= MAX_TRAP_MSG) { 788 uprintf("fatal process exception: %s", 789 trap_msg[type]); 790 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 791 uprintf(", fault VA = 0x%lx", (u_long)eva); 792 uprintf("\n"); 793 } 794 #endif 795 796 user: 797 userret(td, frame); 798 KASSERT(PCB_USER_FPU(td->td_pcb), 799 ("Return from trap with kernel FPU ctx leaked")); 800 userout: 801 out: 802 return; 803 } 804 805 static int 806 trap_pfault(frame, usermode, eva) 807 struct trapframe *frame; 808 int usermode; 809 vm_offset_t eva; 810 { 811 vm_offset_t va; 812 struct vmspace *vm; 813 vm_map_t map; 814 int rv = 0; 815 vm_prot_t ftype; 816 struct thread *td = curthread; 817 struct proc *p = td->td_proc; 818 819 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 820 /* 821 * Due to both processor errata and lazy TLB invalidation when 822 * access restrictions are removed from virtual pages, memory 823 * accesses that are allowed by the physical mapping layer may 824 * nonetheless cause one spurious page fault per virtual page. 825 * When the thread is executing a "no faulting" section that 826 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 827 * every page fault is treated as a spurious page fault, 828 * unless it accesses the same virtual address as the most 829 * recent page fault within the same "no faulting" section. 830 */ 831 if (td->td_md.md_spurflt_addr != eva || 832 (td->td_pflags & TDP_RESETSPUR) != 0) { 833 /* 834 * Do nothing to the TLB. A stale TLB entry is 835 * flushed automatically by a page fault. 836 */ 837 td->td_md.md_spurflt_addr = eva; 838 td->td_pflags &= ~TDP_RESETSPUR; 839 return (0); 840 } 841 } else { 842 /* 843 * If we get a page fault while in a critical section, then 844 * it is most likely a fatal kernel page fault. The kernel 845 * is already going to panic trying to get a sleep lock to 846 * do the VM lookup, so just consider it a fatal trap so the 847 * kernel can print out a useful trap message and even get 848 * to the debugger. 849 * 850 * If we get a page fault while holding a non-sleepable 851 * lock, then it is most likely a fatal kernel page fault. 852 * If WITNESS is enabled, then it's going to whine about 853 * bogus LORs with various VM locks, so just skip to the 854 * fatal trap handling directly. 855 */ 856 if (td->td_critnest != 0 || 857 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 858 "Kernel page fault") != 0) { 859 trap_fatal(frame, eva); 860 return (-1); 861 } 862 } 863 va = trunc_page(eva); 864 if (va >= KERNBASE) { 865 /* 866 * Don't allow user-mode faults in kernel address space. 867 * An exception: if the faulting address is the invalid 868 * instruction entry in the IDT, then the Intel Pentium 869 * F00F bug workaround was triggered, and we need to 870 * treat it is as an illegal instruction, and not a page 871 * fault. 872 */ 873 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 874 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) 875 return (-2); 876 #endif 877 if (usermode) 878 goto nogo; 879 880 map = kernel_map; 881 } else { 882 /* 883 * This is a fault on non-kernel virtual memory. If either 884 * p or p->p_vmspace is NULL, then the fault is fatal. 885 */ 886 if (p == NULL || (vm = p->p_vmspace) == NULL) 887 goto nogo; 888 889 map = &vm->vm_map; 890 891 /* 892 * When accessing a user-space address, kernel must be 893 * ready to accept the page fault, and provide a 894 * handling routine. Since accessing the address 895 * without the handler is a bug, do not try to handle 896 * it normally, and panic immediately. 897 */ 898 if (!usermode && (td->td_intr_nesting_level != 0 || 899 curpcb->pcb_onfault == NULL)) { 900 trap_fatal(frame, eva); 901 return (-1); 902 } 903 } 904 905 /* 906 * PGEX_I is defined only if the execute disable bit capability is 907 * supported and enabled. 908 */ 909 if (frame->tf_err & PGEX_W) 910 ftype = VM_PROT_WRITE; 911 #ifdef PAE 912 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 913 ftype = VM_PROT_EXECUTE; 914 #endif 915 else 916 ftype = VM_PROT_READ; 917 918 if (map != kernel_map) { 919 /* 920 * Keep swapout from messing with us during this 921 * critical time. 922 */ 923 PROC_LOCK(p); 924 ++p->p_lock; 925 PROC_UNLOCK(p); 926 927 /* Fault in the user page: */ 928 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 929 930 PROC_LOCK(p); 931 --p->p_lock; 932 PROC_UNLOCK(p); 933 } else { 934 /* 935 * Don't have to worry about process locking or stacks in the 936 * kernel. 937 */ 938 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 939 } 940 if (rv == KERN_SUCCESS) { 941 #ifdef HWPMC_HOOKS 942 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 943 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 944 if (ftype == VM_PROT_READ) 945 PMC_SOFT_CALL_TF( , , page_fault, read, 946 frame); 947 else 948 PMC_SOFT_CALL_TF( , , page_fault, write, 949 frame); 950 } 951 #endif 952 return (0); 953 } 954 nogo: 955 if (!usermode) { 956 if (td->td_intr_nesting_level == 0 && 957 curpcb->pcb_onfault != NULL) { 958 frame->tf_eip = (int)curpcb->pcb_onfault; 959 return (0); 960 } 961 trap_fatal(frame, eva); 962 return (-1); 963 } 964 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 965 } 966 967 static void 968 trap_fatal(frame, eva) 969 struct trapframe *frame; 970 vm_offset_t eva; 971 { 972 int code, ss, esp; 973 u_int type; 974 struct soft_segment_descriptor softseg; 975 char *msg; 976 977 code = frame->tf_err; 978 type = frame->tf_trapno; 979 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 980 981 if (type <= MAX_TRAP_MSG) 982 msg = trap_msg[type]; 983 else 984 msg = "UNKNOWN"; 985 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 986 frame->tf_eflags & PSL_VM ? "vm86" : 987 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 988 #ifdef SMP 989 /* two separate prints in case of a trap on an unmapped page */ 990 printf("cpuid = %d; ", PCPU_GET(cpuid)); 991 printf("apic id = %02x\n", PCPU_GET(apic_id)); 992 #endif 993 if (type == T_PAGEFLT) { 994 printf("fault virtual address = 0x%x\n", eva); 995 printf("fault code = %s %s, %s\n", 996 code & PGEX_U ? "user" : "supervisor", 997 code & PGEX_W ? "write" : "read", 998 code & PGEX_P ? "protection violation" : "page not present"); 999 } 1000 printf("instruction pointer = 0x%x:0x%x\n", 1001 frame->tf_cs & 0xffff, frame->tf_eip); 1002 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 1003 ss = frame->tf_ss & 0xffff; 1004 esp = frame->tf_esp; 1005 } else { 1006 ss = GSEL(GDATA_SEL, SEL_KPL); 1007 esp = (int)&frame->tf_esp; 1008 } 1009 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 1010 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 1011 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 1012 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 1013 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 1014 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 1015 softseg.ssd_gran); 1016 printf("processor eflags = "); 1017 if (frame->tf_eflags & PSL_T) 1018 printf("trace trap, "); 1019 if (frame->tf_eflags & PSL_I) 1020 printf("interrupt enabled, "); 1021 if (frame->tf_eflags & PSL_NT) 1022 printf("nested task, "); 1023 if (frame->tf_eflags & PSL_RF) 1024 printf("resume, "); 1025 if (frame->tf_eflags & PSL_VM) 1026 printf("vm86, "); 1027 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 1028 printf("current process = "); 1029 if (curproc) { 1030 printf("%lu (%s)\n", (u_long)curproc->p_pid, curthread->td_name); 1031 } else { 1032 printf("Idle\n"); 1033 } 1034 1035 #ifdef KDB 1036 if (debugger_on_panic || kdb_active) { 1037 frame->tf_err = eva; /* smuggle fault address to ddb */ 1038 if (kdb_trap(type, 0, frame)) { 1039 frame->tf_err = code; /* restore error code */ 1040 return; 1041 } 1042 frame->tf_err = code; /* restore error code */ 1043 } 1044 #endif 1045 printf("trap number = %d\n", type); 1046 if (type <= MAX_TRAP_MSG) 1047 panic("%s", trap_msg[type]); 1048 else 1049 panic("unknown/reserved trap"); 1050 } 1051 1052 /* 1053 * Double fault handler. Called when a fault occurs while writing 1054 * a frame for a trap/exception onto the stack. This usually occurs 1055 * when the stack overflows (such is the case with infinite recursion, 1056 * for example). 1057 * 1058 * XXX Note that the current PTD gets replaced by IdlePTD when the 1059 * task switch occurs. This means that the stack that was active at 1060 * the time of the double fault is not available at <kstack> unless 1061 * the machine was idle when the double fault occurred. The downside 1062 * of this is that "trace <ebp>" in ddb won't work. 1063 */ 1064 void 1065 dblfault_handler() 1066 { 1067 #ifdef KDTRACE_HOOKS 1068 if (dtrace_doubletrap_func != NULL) 1069 (*dtrace_doubletrap_func)(); 1070 #endif 1071 printf("\nFatal double fault:\n"); 1072 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 1073 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 1074 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 1075 #ifdef SMP 1076 /* two separate prints in case of a trap on an unmapped page */ 1077 printf("cpuid = %d; ", PCPU_GET(cpuid)); 1078 printf("apic id = %02x\n", PCPU_GET(apic_id)); 1079 #endif 1080 panic("double fault"); 1081 } 1082 1083 int 1084 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 1085 { 1086 struct proc *p; 1087 struct trapframe *frame; 1088 caddr_t params; 1089 int error; 1090 1091 p = td->td_proc; 1092 frame = td->td_frame; 1093 1094 params = (caddr_t)frame->tf_esp + sizeof(int); 1095 sa->code = frame->tf_eax; 1096 1097 /* 1098 * Need to check if this is a 32 bit or 64 bit syscall. 1099 */ 1100 if (sa->code == SYS_syscall) { 1101 /* 1102 * Code is first argument, followed by actual args. 1103 */ 1104 sa->code = fuword(params); 1105 params += sizeof(int); 1106 } else if (sa->code == SYS___syscall) { 1107 /* 1108 * Like syscall, but code is a quad, so as to maintain 1109 * quad alignment for the rest of the arguments. 1110 */ 1111 sa->code = fuword(params); 1112 params += sizeof(quad_t); 1113 } 1114 1115 if (p->p_sysent->sv_mask) 1116 sa->code &= p->p_sysent->sv_mask; 1117 if (sa->code >= p->p_sysent->sv_size) 1118 sa->callp = &p->p_sysent->sv_table[0]; 1119 else 1120 sa->callp = &p->p_sysent->sv_table[sa->code]; 1121 sa->narg = sa->callp->sy_narg; 1122 1123 if (params != NULL && sa->narg != 0) 1124 error = copyin(params, (caddr_t)sa->args, 1125 (u_int)(sa->narg * sizeof(int))); 1126 else 1127 error = 0; 1128 1129 if (error == 0) { 1130 td->td_retval[0] = 0; 1131 td->td_retval[1] = frame->tf_edx; 1132 } 1133 1134 return (error); 1135 } 1136 1137 #include "../../kern/subr_syscall.c" 1138 1139 /* 1140 * syscall - system call request C handler. A system call is 1141 * essentially treated as a trap by reusing the frame layout. 1142 */ 1143 void 1144 syscall(struct trapframe *frame) 1145 { 1146 struct thread *td; 1147 struct syscall_args sa; 1148 register_t orig_tf_eflags; 1149 int error; 1150 ksiginfo_t ksi; 1151 1152 #ifdef DIAGNOSTIC 1153 if (ISPL(frame->tf_cs) != SEL_UPL) { 1154 panic("syscall"); 1155 /* NOT REACHED */ 1156 } 1157 #endif 1158 orig_tf_eflags = frame->tf_eflags; 1159 1160 td = curthread; 1161 td->td_frame = frame; 1162 1163 error = syscallenter(td, &sa); 1164 1165 /* 1166 * Traced syscall. 1167 */ 1168 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { 1169 frame->tf_eflags &= ~PSL_T; 1170 ksiginfo_init_trap(&ksi); 1171 ksi.ksi_signo = SIGTRAP; 1172 ksi.ksi_code = TRAP_TRACE; 1173 ksi.ksi_addr = (void *)frame->tf_eip; 1174 trapsignal(td, &ksi); 1175 } 1176 1177 KASSERT(PCB_USER_FPU(td->td_pcb), 1178 ("System call %s returning with kernel FPU ctx leaked", 1179 syscallname(td->td_proc, sa.code))); 1180 KASSERT(td->td_pcb->pcb_save == &td->td_pcb->pcb_user_save, 1181 ("System call %s returning with mangled pcb_save", 1182 syscallname(td->td_proc, sa.code))); 1183 1184 syscallret(td, error, &sa); 1185 }
Cache object: 5b20a79401ad8b467086fda385ba050c
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