Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/trap.c
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1 /*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the University of Utah, and William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 38 */ 39 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 /* 44 * 386 Trap and System call handling 45 */ 46 47 #include "opt_clock.h" 48 #include "opt_cpu.h" 49 #include "opt_hwpmc_hooks.h" 50 #include "opt_isa.h" 51 #include "opt_kdb.h" 52 #include "opt_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 and usdt providers. 127 */ 128 dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr; 129 dtrace_return_probe_ptr_t dtrace_return_probe_ptr; 130 #endif 131 132 extern void trap(struct trapframe *frame); 133 extern void syscall(struct trapframe *frame); 134 135 static int trap_pfault(struct trapframe *, int, vm_offset_t); 136 static void trap_fatal(struct trapframe *, vm_offset_t); 137 void dblfault_handler(void); 138 139 extern inthand_t IDTVEC(lcall_syscall); 140 141 #define MAX_TRAP_MSG 32 142 static char *trap_msg[] = { 143 "", /* 0 unused */ 144 "privileged instruction fault", /* 1 T_PRIVINFLT */ 145 "", /* 2 unused */ 146 "breakpoint instruction fault", /* 3 T_BPTFLT */ 147 "", /* 4 unused */ 148 "", /* 5 unused */ 149 "arithmetic trap", /* 6 T_ARITHTRAP */ 150 "", /* 7 unused */ 151 "", /* 8 unused */ 152 "general protection fault", /* 9 T_PROTFLT */ 153 "trace trap", /* 10 T_TRCTRAP */ 154 "", /* 11 unused */ 155 "page fault", /* 12 T_PAGEFLT */ 156 "", /* 13 unused */ 157 "alignment fault", /* 14 T_ALIGNFLT */ 158 "", /* 15 unused */ 159 "", /* 16 unused */ 160 "", /* 17 unused */ 161 "integer divide fault", /* 18 T_DIVIDE */ 162 "non-maskable interrupt trap", /* 19 T_NMI */ 163 "overflow trap", /* 20 T_OFLOW */ 164 "FPU bounds check fault", /* 21 T_BOUND */ 165 "FPU device not available", /* 22 T_DNA */ 166 "double fault", /* 23 T_DOUBLEFLT */ 167 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 168 "invalid TSS fault", /* 25 T_TSSFLT */ 169 "segment not present fault", /* 26 T_SEGNPFLT */ 170 "stack fault", /* 27 T_STKFLT */ 171 "machine check trap", /* 28 T_MCHK */ 172 "SIMD floating-point exception", /* 29 T_XMMFLT */ 173 "reserved (unknown) fault", /* 30 T_RESERVED */ 174 "", /* 31 unused (reserved) */ 175 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 176 }; 177 178 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 179 extern int has_f00f_bug; 180 #endif 181 182 #ifdef KDB 183 static int kdb_on_nmi = 1; 184 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 185 &kdb_on_nmi, 0, "Go to KDB on NMI"); 186 TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi); 187 #endif 188 static int panic_on_nmi = 1; 189 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 190 &panic_on_nmi, 0, "Panic on NMI"); 191 TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi); 192 static int prot_fault_translation = 0; 193 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 194 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 195 static int uprintf_signal; 196 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW, 197 &uprintf_signal, 0, 198 "Print debugging information on trap signal to ctty"); 199 200 /* 201 * Exception, fault, and trap interface to the FreeBSD kernel. 202 * This common code is called from assembly language IDT gate entry 203 * routines that prepare a suitable stack frame, and restore this 204 * frame after the exception has been processed. 205 */ 206 207 void 208 trap(struct trapframe *frame) 209 { 210 #ifdef KDTRACE_HOOKS 211 struct reg regs; 212 #endif 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 its 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 ((type == T_PROTFLT || type == T_PAGEFLT) && 274 dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type)) 275 goto out; 276 #endif 277 278 if ((frame->tf_eflags & PSL_I) == 0) { 279 /* 280 * Buggy application or kernel code has disabled 281 * interrupts and then trapped. Enabling interrupts 282 * now is wrong, but it is better than running with 283 * interrupts disabled until they are accidentally 284 * enabled later. 285 */ 286 if (ISPL(frame->tf_cs) == SEL_UPL || (frame->tf_eflags & PSL_VM)) 287 uprintf( 288 "pid %ld (%s): trap %d with interrupts disabled\n", 289 (long)curproc->p_pid, curthread->td_name, type); 290 else if (type != T_BPTFLT && type != T_TRCTRAP && 291 frame->tf_eip != (int)cpu_switch_load_gs) { 292 /* 293 * XXX not quite right, since this may be for a 294 * multiple fault in user mode. 295 */ 296 printf("kernel trap %d with interrupts disabled\n", 297 type); 298 /* 299 * Page faults need interrupts disabled until later, 300 * and we shouldn't enable interrupts while holding 301 * a spin lock or if servicing an NMI. 302 */ 303 if (type != T_NMI && type != T_PAGEFLT && 304 td->td_md.md_spinlock_count == 0) 305 enable_intr(); 306 } 307 } 308 eva = 0; 309 code = frame->tf_err; 310 if (type == T_PAGEFLT) { 311 /* 312 * For some Cyrix CPUs, %cr2 is clobbered by 313 * interrupts. This problem is worked around by using 314 * an interrupt gate for the pagefault handler. We 315 * are finally ready to read %cr2 and conditionally 316 * reenable interrupts. If we hold a spin lock, then 317 * we must not reenable interrupts. This might be a 318 * spurious page fault. 319 */ 320 eva = rcr2(); 321 if (td->td_md.md_spinlock_count == 0) 322 enable_intr(); 323 } 324 325 if ((ISPL(frame->tf_cs) == SEL_UPL) || 326 ((frame->tf_eflags & PSL_VM) && 327 !(curpcb->pcb_flags & PCB_VM86CALL))) { 328 /* user trap */ 329 330 td->td_pticks = 0; 331 td->td_frame = frame; 332 addr = frame->tf_eip; 333 if (td->td_ucred != p->p_ucred) 334 cred_update_thread(td); 335 336 switch (type) { 337 case T_PRIVINFLT: /* privileged instruction fault */ 338 i = SIGILL; 339 ucode = ILL_PRVOPC; 340 break; 341 342 case T_BPTFLT: /* bpt instruction fault */ 343 case T_TRCTRAP: /* trace trap */ 344 enable_intr(); 345 #ifdef KDTRACE_HOOKS 346 if (type == T_BPTFLT) { 347 fill_frame_regs(frame, ®s); 348 if (dtrace_pid_probe_ptr != NULL && 349 dtrace_pid_probe_ptr(®s) == 0) 350 goto out; 351 } 352 #endif 353 frame->tf_eflags &= ~PSL_T; 354 i = SIGTRAP; 355 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 356 break; 357 358 case T_ARITHTRAP: /* arithmetic trap */ 359 #ifdef DEV_NPX 360 ucode = npxtrap_x87(); 361 if (ucode == -1) 362 goto userout; 363 #else 364 ucode = 0; 365 #endif 366 i = SIGFPE; 367 break; 368 369 /* 370 * The following two traps can happen in 371 * vm86 mode, and, if so, we want to handle 372 * them specially. 373 */ 374 case T_PROTFLT: /* general protection fault */ 375 case T_STKFLT: /* stack fault */ 376 if (frame->tf_eflags & PSL_VM) { 377 i = vm86_emulate((struct vm86frame *)frame); 378 if (i == 0) 379 goto user; 380 break; 381 } 382 i = SIGBUS; 383 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; 384 break; 385 case T_SEGNPFLT: /* segment not present fault */ 386 i = SIGBUS; 387 ucode = BUS_ADRERR; 388 break; 389 case T_TSSFLT: /* invalid TSS fault */ 390 i = SIGBUS; 391 ucode = BUS_OBJERR; 392 break; 393 case T_ALIGNFLT: 394 i = SIGBUS; 395 ucode = BUS_ADRALN; 396 break; 397 case T_DOUBLEFLT: /* double fault */ 398 default: 399 i = SIGBUS; 400 ucode = BUS_OBJERR; 401 break; 402 403 case T_PAGEFLT: /* page fault */ 404 405 i = trap_pfault(frame, TRUE, eva); 406 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 407 if (i == -2) { 408 /* 409 * The f00f hack workaround has triggered, so 410 * treat the fault as an illegal instruction 411 * (T_PRIVINFLT) instead of a page fault. 412 */ 413 type = frame->tf_trapno = T_PRIVINFLT; 414 415 /* Proceed as in that case. */ 416 ucode = ILL_PRVOPC; 417 i = SIGILL; 418 break; 419 } 420 #endif 421 if (i == -1) 422 goto userout; 423 if (i == 0) 424 goto user; 425 426 if (i == SIGSEGV) 427 ucode = SEGV_MAPERR; 428 else { 429 if (prot_fault_translation == 0) { 430 /* 431 * Autodetect. 432 * This check also covers the images 433 * without the ABI-tag ELF note. 434 */ 435 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 436 && p->p_osrel >= P_OSREL_SIGSEGV) { 437 i = SIGSEGV; 438 ucode = SEGV_ACCERR; 439 } else { 440 i = SIGBUS; 441 ucode = BUS_PAGE_FAULT; 442 } 443 } else if (prot_fault_translation == 1) { 444 /* 445 * Always compat mode. 446 */ 447 i = SIGBUS; 448 ucode = BUS_PAGE_FAULT; 449 } else { 450 /* 451 * Always SIGSEGV mode. 452 */ 453 i = SIGSEGV; 454 ucode = SEGV_ACCERR; 455 } 456 } 457 addr = eva; 458 break; 459 460 case T_DIVIDE: /* integer divide fault */ 461 ucode = FPE_INTDIV; 462 i = SIGFPE; 463 break; 464 465 #ifdef DEV_ISA 466 case T_NMI: 467 #ifdef POWERFAIL_NMI 468 #ifndef TIMER_FREQ 469 # define TIMER_FREQ 1193182 470 #endif 471 if (time_second - lastalert > 10) { 472 log(LOG_WARNING, "NMI: power fail\n"); 473 sysbeep(880, hz); 474 lastalert = time_second; 475 } 476 goto userout; 477 #else /* !POWERFAIL_NMI */ 478 /* machine/parity/power fail/"kitchen sink" faults */ 479 if (isa_nmi(code) == 0) { 480 #ifdef KDB 481 /* 482 * NMI can be hooked up to a pushbutton 483 * for debugging. 484 */ 485 if (kdb_on_nmi) { 486 printf ("NMI ... going to debugger\n"); 487 kdb_trap(type, 0, frame); 488 } 489 #endif /* KDB */ 490 goto userout; 491 } else if (panic_on_nmi) 492 panic("NMI indicates hardware failure"); 493 break; 494 #endif /* POWERFAIL_NMI */ 495 #endif /* DEV_ISA */ 496 497 case T_OFLOW: /* integer overflow fault */ 498 ucode = FPE_INTOVF; 499 i = SIGFPE; 500 break; 501 502 case T_BOUND: /* bounds check fault */ 503 ucode = FPE_FLTSUB; 504 i = SIGFPE; 505 break; 506 507 case T_DNA: 508 #ifdef DEV_NPX 509 KASSERT(PCB_USER_FPU(td->td_pcb), 510 ("kernel FPU ctx has leaked")); 511 /* transparent fault (due to context switch "late") */ 512 if (npxdna()) 513 goto userout; 514 #endif 515 uprintf("pid %d killed due to lack of floating point\n", 516 p->p_pid); 517 i = SIGKILL; 518 ucode = 0; 519 break; 520 521 case T_FPOPFLT: /* FPU operand fetch fault */ 522 ucode = ILL_COPROC; 523 i = SIGILL; 524 break; 525 526 case T_XMMFLT: /* SIMD floating-point exception */ 527 #if defined(DEV_NPX) && !defined(CPU_DISABLE_SSE) && defined(I686_CPU) 528 ucode = npxtrap_sse(); 529 if (ucode == -1) 530 goto userout; 531 #else 532 ucode = 0; 533 #endif 534 i = SIGFPE; 535 break; 536 #ifdef KDTRACE_HOOKS 537 case T_DTRACE_RET: 538 enable_intr(); 539 fill_frame_regs(frame, ®s); 540 if (dtrace_return_probe_ptr != NULL && 541 dtrace_return_probe_ptr(®s) == 0) 542 goto out; 543 break; 544 #endif 545 } 546 } else { 547 /* kernel trap */ 548 549 KASSERT(cold || td->td_ucred != NULL, 550 ("kernel trap doesn't have ucred")); 551 switch (type) { 552 case T_PAGEFLT: /* page fault */ 553 (void) trap_pfault(frame, FALSE, eva); 554 goto out; 555 556 case T_DNA: 557 #ifdef DEV_NPX 558 KASSERT(!PCB_USER_FPU(td->td_pcb), 559 ("Unregistered use of FPU in kernel")); 560 if (npxdna()) 561 goto out; 562 #endif 563 break; 564 565 case T_ARITHTRAP: /* arithmetic trap */ 566 case T_XMMFLT: /* SIMD floating-point exception */ 567 case T_FPOPFLT: /* FPU operand fetch fault */ 568 /* 569 * XXXKIB for now disable any FPU traps in kernel 570 * handler registration seems to be overkill 571 */ 572 trap_fatal(frame, 0); 573 goto out; 574 575 /* 576 * The following two traps can happen in 577 * vm86 mode, and, if so, we want to handle 578 * them specially. 579 */ 580 case T_PROTFLT: /* general protection fault */ 581 case T_STKFLT: /* stack fault */ 582 if (frame->tf_eflags & PSL_VM) { 583 i = vm86_emulate((struct vm86frame *)frame); 584 if (i != 0) 585 /* 586 * returns to original process 587 */ 588 vm86_trap((struct vm86frame *)frame); 589 goto out; 590 } 591 if (type == T_STKFLT) 592 break; 593 594 /* FALL THROUGH */ 595 596 case T_SEGNPFLT: /* segment not present fault */ 597 if (curpcb->pcb_flags & PCB_VM86CALL) 598 break; 599 600 /* 601 * Invalid %fs's and %gs's can be created using 602 * procfs or PT_SETREGS or by invalidating the 603 * underlying LDT entry. This causes a fault 604 * in kernel mode when the kernel attempts to 605 * switch contexts. Lose the bad context 606 * (XXX) so that we can continue, and generate 607 * a signal. 608 */ 609 if (frame->tf_eip == (int)cpu_switch_load_gs) { 610 curpcb->pcb_gs = 0; 611 #if 0 612 PROC_LOCK(p); 613 kern_psignal(p, SIGBUS); 614 PROC_UNLOCK(p); 615 #endif 616 goto out; 617 } 618 619 if (td->td_intr_nesting_level != 0) 620 break; 621 622 /* 623 * Invalid segment selectors and out of bounds 624 * %eip's and %esp's can be set up in user mode. 625 * This causes a fault in kernel mode when the 626 * kernel tries to return to user mode. We want 627 * to get this fault so that we can fix the 628 * problem here and not have to check all the 629 * selectors and pointers when the user changes 630 * them. 631 */ 632 if (frame->tf_eip == (int)doreti_iret) { 633 frame->tf_eip = (int)doreti_iret_fault; 634 goto out; 635 } 636 if (frame->tf_eip == (int)doreti_popl_ds) { 637 frame->tf_eip = (int)doreti_popl_ds_fault; 638 goto out; 639 } 640 if (frame->tf_eip == (int)doreti_popl_es) { 641 frame->tf_eip = (int)doreti_popl_es_fault; 642 goto out; 643 } 644 if (frame->tf_eip == (int)doreti_popl_fs) { 645 frame->tf_eip = (int)doreti_popl_fs_fault; 646 goto out; 647 } 648 if (curpcb->pcb_onfault != NULL) { 649 frame->tf_eip = 650 (int)curpcb->pcb_onfault; 651 goto out; 652 } 653 break; 654 655 case T_TSSFLT: 656 /* 657 * PSL_NT can be set in user mode and isn't cleared 658 * automatically when the kernel is entered. This 659 * causes a TSS fault when the kernel attempts to 660 * `iret' because the TSS link is uninitialized. We 661 * want to get this fault so that we can fix the 662 * problem here and not every time the kernel is 663 * entered. 664 */ 665 if (frame->tf_eflags & PSL_NT) { 666 frame->tf_eflags &= ~PSL_NT; 667 goto out; 668 } 669 break; 670 671 case T_TRCTRAP: /* trace trap */ 672 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) { 673 /* 674 * We've just entered system mode via the 675 * syscall lcall. Continue single stepping 676 * silently until the syscall handler has 677 * saved the flags. 678 */ 679 goto out; 680 } 681 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 682 /* 683 * The syscall handler has now saved the 684 * flags. Stop single stepping it. 685 */ 686 frame->tf_eflags &= ~PSL_T; 687 goto out; 688 } 689 /* 690 * Ignore debug register trace traps due to 691 * accesses in the user's address space, which 692 * can happen under several conditions such as 693 * if a user sets a watchpoint on a buffer and 694 * then passes that buffer to a system call. 695 * We still want to get TRCTRAPS for addresses 696 * in kernel space because that is useful when 697 * debugging the kernel. 698 */ 699 if (user_dbreg_trap() && 700 !(curpcb->pcb_flags & PCB_VM86CALL)) { 701 /* 702 * Reset breakpoint bits because the 703 * processor doesn't 704 */ 705 load_dr6(rdr6() & 0xfffffff0); 706 goto out; 707 } 708 /* 709 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 710 */ 711 case T_BPTFLT: 712 /* 713 * If KDB is enabled, let it handle the debugger trap. 714 * Otherwise, debugger traps "can't happen". 715 */ 716 #ifdef KDB 717 if (kdb_trap(type, 0, frame)) 718 goto out; 719 #endif 720 break; 721 722 #ifdef DEV_ISA 723 case T_NMI: 724 #ifdef POWERFAIL_NMI 725 if (time_second - lastalert > 10) { 726 log(LOG_WARNING, "NMI: power fail\n"); 727 sysbeep(880, hz); 728 lastalert = time_second; 729 } 730 goto out; 731 #else /* !POWERFAIL_NMI */ 732 /* machine/parity/power fail/"kitchen sink" faults */ 733 if (isa_nmi(code) == 0) { 734 #ifdef KDB 735 /* 736 * NMI can be hooked up to a pushbutton 737 * for debugging. 738 */ 739 if (kdb_on_nmi) { 740 printf ("NMI ... going to debugger\n"); 741 kdb_trap(type, 0, frame); 742 } 743 #endif /* KDB */ 744 goto out; 745 } else if (panic_on_nmi == 0) 746 goto out; 747 /* FALLTHROUGH */ 748 #endif /* POWERFAIL_NMI */ 749 #endif /* DEV_ISA */ 750 } 751 752 trap_fatal(frame, eva); 753 goto out; 754 } 755 756 /* Translate fault for emulators (e.g. Linux) */ 757 if (*p->p_sysent->sv_transtrap) 758 i = (*p->p_sysent->sv_transtrap)(i, type); 759 760 ksiginfo_init_trap(&ksi); 761 ksi.ksi_signo = i; 762 ksi.ksi_code = ucode; 763 ksi.ksi_addr = (void *)addr; 764 ksi.ksi_trapno = type; 765 if (uprintf_signal) { 766 uprintf("pid %d comm %s: signal %d err %x code %d type %d " 767 "addr 0x%x esp 0x%08x eip 0x%08x " 768 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 769 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 770 frame->tf_esp, frame->tf_eip, 771 fubyte((void *)(frame->tf_eip + 0)), 772 fubyte((void *)(frame->tf_eip + 1)), 773 fubyte((void *)(frame->tf_eip + 2)), 774 fubyte((void *)(frame->tf_eip + 3)), 775 fubyte((void *)(frame->tf_eip + 4)), 776 fubyte((void *)(frame->tf_eip + 5)), 777 fubyte((void *)(frame->tf_eip + 6)), 778 fubyte((void *)(frame->tf_eip + 7))); 779 } 780 KASSERT((read_eflags() & PSL_I) != 0, ("interrupts disabled")); 781 trapsignal(td, &ksi); 782 783 #ifdef DEBUG 784 if (type <= MAX_TRAP_MSG) { 785 uprintf("fatal process exception: %s", 786 trap_msg[type]); 787 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 788 uprintf(", fault VA = 0x%lx", (u_long)eva); 789 uprintf("\n"); 790 } 791 #endif 792 793 user: 794 userret(td, frame); 795 mtx_assert(&Giant, MA_NOTOWNED); 796 KASSERT(PCB_USER_FPU(td->td_pcb), 797 ("Return from trap with kernel FPU ctx leaked")); 798 userout: 799 out: 800 return; 801 } 802 803 static int 804 trap_pfault(frame, usermode, eva) 805 struct trapframe *frame; 806 int usermode; 807 vm_offset_t eva; 808 { 809 vm_offset_t va; 810 struct vmspace *vm = NULL; 811 vm_map_t map; 812 int rv = 0; 813 vm_prot_t ftype; 814 struct thread *td = curthread; 815 struct proc *p = td->td_proc; 816 817 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 818 /* 819 * Due to both processor errata and lazy TLB invalidation when 820 * access restrictions are removed from virtual pages, memory 821 * accesses that are allowed by the physical mapping layer may 822 * nonetheless cause one spurious page fault per virtual page. 823 * When the thread is executing a "no faulting" section that 824 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 825 * every page fault is treated as a spurious page fault, 826 * unless it accesses the same virtual address as the most 827 * recent page fault within the same "no faulting" section. 828 */ 829 if (td->td_md.md_spurflt_addr != eva || 830 (td->td_pflags & TDP_RESETSPUR) != 0) { 831 /* 832 * Do nothing to the TLB. A stale TLB entry is 833 * flushed automatically by a page fault. 834 */ 835 td->td_md.md_spurflt_addr = eva; 836 td->td_pflags &= ~TDP_RESETSPUR; 837 return (0); 838 } 839 } else { 840 /* 841 * If we get a page fault while in a critical section, then 842 * it is most likely a fatal kernel page fault. The kernel 843 * is already going to panic trying to get a sleep lock to 844 * do the VM lookup, so just consider it a fatal trap so the 845 * kernel can print out a useful trap message and even get 846 * to the debugger. 847 * 848 * If we get a page fault while holding a non-sleepable 849 * lock, then it is most likely a fatal kernel page fault. 850 * If WITNESS is enabled, then it's going to whine about 851 * bogus LORs with various VM locks, so just skip to the 852 * fatal trap handling directly. 853 */ 854 if (td->td_critnest != 0 || 855 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 856 "Kernel page fault") != 0) { 857 trap_fatal(frame, eva); 858 return (-1); 859 } 860 } 861 va = trunc_page(eva); 862 if (va >= KERNBASE) { 863 /* 864 * Don't allow user-mode faults in kernel address space. 865 * An exception: if the faulting address is the invalid 866 * instruction entry in the IDT, then the Intel Pentium 867 * F00F bug workaround was triggered, and we need to 868 * treat it is as an illegal instruction, and not a page 869 * fault. 870 */ 871 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 872 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) 873 return -2; 874 #endif 875 if (usermode) 876 goto nogo; 877 878 map = kernel_map; 879 } else { 880 /* 881 * This is a fault on non-kernel virtual memory. 882 * vm is initialized above to NULL. If curproc is NULL 883 * or curproc->p_vmspace is NULL the fault is fatal. 884 */ 885 if (p != NULL) 886 vm = p->p_vmspace; 887 888 if (vm == NULL) 889 goto nogo; 890 891 map = &vm->vm_map; 892 if (!usermode && (td->td_intr_nesting_level != 0 || 893 curpcb->pcb_onfault == NULL)) { 894 trap_fatal(frame, eva); 895 return (-1); 896 } 897 } 898 899 /* 900 * PGEX_I is defined only if the execute disable bit capability is 901 * supported and enabled. 902 */ 903 if (frame->tf_err & PGEX_W) 904 ftype = VM_PROT_WRITE; 905 #ifdef PAE 906 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 907 ftype = VM_PROT_EXECUTE; 908 #endif 909 else 910 ftype = VM_PROT_READ; 911 912 if (map != kernel_map) { 913 /* 914 * Keep swapout from messing with us during this 915 * critical time. 916 */ 917 PROC_LOCK(p); 918 ++p->p_lock; 919 PROC_UNLOCK(p); 920 921 /* Fault in the user page: */ 922 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 923 924 PROC_LOCK(p); 925 --p->p_lock; 926 PROC_UNLOCK(p); 927 } else { 928 /* 929 * Don't have to worry about process locking or stacks in the 930 * kernel. 931 */ 932 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 933 } 934 if (rv == KERN_SUCCESS) { 935 #ifdef HWPMC_HOOKS 936 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 937 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 938 if (ftype == VM_PROT_READ) 939 PMC_SOFT_CALL_TF( , , page_fault, read, 940 frame); 941 else 942 PMC_SOFT_CALL_TF( , , page_fault, write, 943 frame); 944 } 945 #endif 946 return (0); 947 } 948 nogo: 949 if (!usermode) { 950 if (td->td_intr_nesting_level == 0 && 951 curpcb->pcb_onfault != NULL) { 952 frame->tf_eip = (int)curpcb->pcb_onfault; 953 return (0); 954 } 955 trap_fatal(frame, eva); 956 return (-1); 957 } 958 959 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 960 } 961 962 static void 963 trap_fatal(frame, eva) 964 struct trapframe *frame; 965 vm_offset_t eva; 966 { 967 int code, ss, esp; 968 u_int type; 969 struct soft_segment_descriptor softseg; 970 char *msg; 971 972 code = frame->tf_err; 973 type = frame->tf_trapno; 974 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 975 976 if (type <= MAX_TRAP_MSG) 977 msg = trap_msg[type]; 978 else 979 msg = "UNKNOWN"; 980 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 981 frame->tf_eflags & PSL_VM ? "vm86" : 982 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 983 #ifdef SMP 984 /* two separate prints in case of a trap on an unmapped page */ 985 printf("cpuid = %d; ", PCPU_GET(cpuid)); 986 printf("apic id = %02x\n", PCPU_GET(apic_id)); 987 #endif 988 if (type == T_PAGEFLT) { 989 printf("fault virtual address = 0x%x\n", eva); 990 printf("fault code = %s %s, %s\n", 991 code & PGEX_U ? "user" : "supervisor", 992 code & PGEX_W ? "write" : "read", 993 code & PGEX_P ? "protection violation" : "page not present"); 994 } 995 printf("instruction pointer = 0x%x:0x%x\n", 996 frame->tf_cs & 0xffff, frame->tf_eip); 997 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 998 ss = frame->tf_ss & 0xffff; 999 esp = frame->tf_esp; 1000 } else { 1001 ss = GSEL(GDATA_SEL, SEL_KPL); 1002 esp = (int)&frame->tf_esp; 1003 } 1004 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 1005 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 1006 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 1007 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 1008 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 1009 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 1010 softseg.ssd_gran); 1011 printf("processor eflags = "); 1012 if (frame->tf_eflags & PSL_T) 1013 printf("trace trap, "); 1014 if (frame->tf_eflags & PSL_I) 1015 printf("interrupt enabled, "); 1016 if (frame->tf_eflags & PSL_NT) 1017 printf("nested task, "); 1018 if (frame->tf_eflags & PSL_RF) 1019 printf("resume, "); 1020 if (frame->tf_eflags & PSL_VM) 1021 printf("vm86, "); 1022 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 1023 printf("current process = %d (%s)\n", 1024 curproc->p_pid, curthread->td_name); 1025 1026 #ifdef KDB 1027 if (debugger_on_panic || kdb_active) { 1028 frame->tf_err = eva; /* smuggle fault address to ddb */ 1029 if (kdb_trap(type, 0, frame)) { 1030 frame->tf_err = code; /* restore error code */ 1031 return; 1032 } 1033 frame->tf_err = code; /* restore error code */ 1034 } 1035 #endif 1036 printf("trap number = %d\n", type); 1037 if (type <= MAX_TRAP_MSG) 1038 panic("%s", trap_msg[type]); 1039 else 1040 panic("unknown/reserved trap"); 1041 } 1042 1043 /* 1044 * Double fault handler. Called when a fault occurs while writing 1045 * a frame for a trap/exception onto the stack. This usually occurs 1046 * when the stack overflows (such is the case with infinite recursion, 1047 * for example). 1048 * 1049 * XXX Note that the current PTD gets replaced by IdlePTD when the 1050 * task switch occurs. This means that the stack that was active at 1051 * the time of the double fault is not available at <kstack> unless 1052 * the machine was idle when the double fault occurred. The downside 1053 * of this is that "trace <ebp>" in ddb won't work. 1054 */ 1055 void 1056 dblfault_handler() 1057 { 1058 #ifdef KDTRACE_HOOKS 1059 if (dtrace_doubletrap_func != NULL) 1060 (*dtrace_doubletrap_func)(); 1061 #endif 1062 printf("\nFatal double fault:\n"); 1063 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 1064 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 1065 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 1066 #ifdef SMP 1067 /* two separate prints in case of a trap on an unmapped page */ 1068 printf("cpuid = %d; ", PCPU_GET(cpuid)); 1069 printf("apic id = %02x\n", PCPU_GET(apic_id)); 1070 #endif 1071 panic("double fault"); 1072 } 1073 1074 int 1075 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 1076 { 1077 struct proc *p; 1078 struct trapframe *frame; 1079 caddr_t params; 1080 int error; 1081 1082 p = td->td_proc; 1083 frame = td->td_frame; 1084 1085 params = (caddr_t)frame->tf_esp + sizeof(int); 1086 sa->code = frame->tf_eax; 1087 1088 /* 1089 * Need to check if this is a 32 bit or 64 bit syscall. 1090 */ 1091 if (sa->code == SYS_syscall) { 1092 /* 1093 * Code is first argument, followed by actual args. 1094 */ 1095 sa->code = fuword(params); 1096 params += sizeof(int); 1097 } else if (sa->code == SYS___syscall) { 1098 /* 1099 * Like syscall, but code is a quad, so as to maintain 1100 * quad alignment for the rest of the arguments. 1101 */ 1102 sa->code = fuword(params); 1103 params += sizeof(quad_t); 1104 } 1105 1106 if (p->p_sysent->sv_mask) 1107 sa->code &= p->p_sysent->sv_mask; 1108 if (sa->code >= p->p_sysent->sv_size) 1109 sa->callp = &p->p_sysent->sv_table[0]; 1110 else 1111 sa->callp = &p->p_sysent->sv_table[sa->code]; 1112 sa->narg = sa->callp->sy_narg; 1113 1114 if (params != NULL && sa->narg != 0) 1115 error = copyin(params, (caddr_t)sa->args, 1116 (u_int)(sa->narg * sizeof(int))); 1117 else 1118 error = 0; 1119 1120 if (error == 0) { 1121 td->td_retval[0] = 0; 1122 td->td_retval[1] = frame->tf_edx; 1123 } 1124 1125 return (error); 1126 } 1127 1128 #include "../../kern/subr_syscall.c" 1129 1130 /* 1131 * syscall - system call request C handler. A system call is 1132 * essentially treated as a trap by reusing the frame layout. 1133 */ 1134 void 1135 syscall(struct trapframe *frame) 1136 { 1137 struct thread *td; 1138 struct syscall_args sa; 1139 register_t orig_tf_eflags; 1140 int error; 1141 ksiginfo_t ksi; 1142 1143 #ifdef DIAGNOSTIC 1144 if (ISPL(frame->tf_cs) != SEL_UPL) { 1145 panic("syscall"); 1146 /* NOT REACHED */ 1147 } 1148 #endif 1149 orig_tf_eflags = frame->tf_eflags; 1150 1151 td = curthread; 1152 td->td_frame = frame; 1153 1154 error = syscallenter(td, &sa); 1155 1156 /* 1157 * Traced syscall. 1158 */ 1159 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { 1160 frame->tf_eflags &= ~PSL_T; 1161 ksiginfo_init_trap(&ksi); 1162 ksi.ksi_signo = SIGTRAP; 1163 ksi.ksi_code = TRAP_TRACE; 1164 ksi.ksi_addr = (void *)frame->tf_eip; 1165 trapsignal(td, &ksi); 1166 } 1167 1168 KASSERT(PCB_USER_FPU(td->td_pcb), 1169 ("System call %s returning with kernel FPU ctx leaked", 1170 syscallname(td->td_proc, sa.code))); 1171 KASSERT(td->td_pcb->pcb_save == &td->td_pcb->pcb_user_save, 1172 ("System call %s returning with mangled pcb_save", 1173 syscallname(td->td_proc, sa.code))); 1174 1175 syscallret(td, error, &sa); 1176 }
Cache object: fd5a6c497713fade2c96d23df8b79569
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