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/9.2/sys/i386/i386/trap.c 251594 2013-06-10 04:12:48Z 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_BPTFLT && type != T_TRCTRAP && 314 frame->tf_eip != (int)cpu_switch_load_gs) { 315 /* 316 * XXX not quite right, since this may be for a 317 * multiple fault in user mode. 318 */ 319 printf("kernel trap %d with interrupts disabled\n", 320 type); 321 /* 322 * Page faults need interrupts disabled until later, 323 * and we shouldn't enable interrupts while holding 324 * a spin lock or if servicing an NMI. 325 */ 326 if (type != T_NMI && type != T_PAGEFLT && 327 td->td_md.md_spinlock_count == 0) 328 enable_intr(); 329 } 330 } 331 eva = 0; 332 code = frame->tf_err; 333 if (type == T_PAGEFLT) { 334 /* 335 * For some Cyrix CPUs, %cr2 is clobbered by 336 * interrupts. This problem is worked around by using 337 * an interrupt gate for the pagefault handler. We 338 * are finally ready to read %cr2 and conditionally 339 * reenable interrupts. If we hold a spin lock, then 340 * we must not reenable interrupts. This might be a 341 * spurious page fault. 342 */ 343 eva = rcr2(); 344 if (td->td_md.md_spinlock_count == 0) 345 enable_intr(); 346 } 347 348 if ((ISPL(frame->tf_cs) == SEL_UPL) || 349 ((frame->tf_eflags & PSL_VM) && 350 !(curpcb->pcb_flags & PCB_VM86CALL))) { 351 /* user trap */ 352 353 td->td_pticks = 0; 354 td->td_frame = frame; 355 addr = frame->tf_eip; 356 if (td->td_ucred != p->p_ucred) 357 cred_update_thread(td); 358 359 switch (type) { 360 case T_PRIVINFLT: /* privileged instruction fault */ 361 i = SIGILL; 362 ucode = ILL_PRVOPC; 363 break; 364 365 case T_BPTFLT: /* bpt instruction fault */ 366 case T_TRCTRAP: /* trace trap */ 367 enable_intr(); 368 frame->tf_eflags &= ~PSL_T; 369 i = SIGTRAP; 370 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 371 break; 372 373 case T_ARITHTRAP: /* arithmetic trap */ 374 #ifdef DEV_NPX 375 ucode = npxtrap_x87(); 376 if (ucode == -1) 377 goto userout; 378 #else 379 ucode = 0; 380 #endif 381 i = SIGFPE; 382 break; 383 384 /* 385 * The following two traps can happen in 386 * vm86 mode, and, if so, we want to handle 387 * them specially. 388 */ 389 case T_PROTFLT: /* general protection fault */ 390 case T_STKFLT: /* stack fault */ 391 if (frame->tf_eflags & PSL_VM) { 392 i = vm86_emulate((struct vm86frame *)frame); 393 if (i == 0) 394 goto user; 395 break; 396 } 397 i = SIGBUS; 398 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; 399 break; 400 case T_SEGNPFLT: /* segment not present fault */ 401 i = SIGBUS; 402 ucode = BUS_ADRERR; 403 break; 404 case T_TSSFLT: /* invalid TSS fault */ 405 i = SIGBUS; 406 ucode = BUS_OBJERR; 407 break; 408 case T_DOUBLEFLT: /* double fault */ 409 default: 410 i = SIGBUS; 411 ucode = BUS_OBJERR; 412 break; 413 414 case T_PAGEFLT: /* page fault */ 415 416 i = trap_pfault(frame, TRUE, eva); 417 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 418 if (i == -2) { 419 /* 420 * The f00f hack workaround has triggered, so 421 * treat the fault as an illegal instruction 422 * (T_PRIVINFLT) instead of a page fault. 423 */ 424 type = frame->tf_trapno = T_PRIVINFLT; 425 426 /* Proceed as in that case. */ 427 ucode = ILL_PRVOPC; 428 i = SIGILL; 429 break; 430 } 431 #endif 432 if (i == -1) 433 goto userout; 434 if (i == 0) 435 goto user; 436 437 if (i == SIGSEGV) 438 ucode = SEGV_MAPERR; 439 else { 440 if (prot_fault_translation == 0) { 441 /* 442 * Autodetect. 443 * This check also covers the images 444 * without the ABI-tag ELF note. 445 */ 446 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 447 && p->p_osrel >= P_OSREL_SIGSEGV) { 448 i = SIGSEGV; 449 ucode = SEGV_ACCERR; 450 } else { 451 i = SIGBUS; 452 ucode = BUS_PAGE_FAULT; 453 } 454 } else if (prot_fault_translation == 1) { 455 /* 456 * Always compat mode. 457 */ 458 i = SIGBUS; 459 ucode = BUS_PAGE_FAULT; 460 } else { 461 /* 462 * Always SIGSEGV mode. 463 */ 464 i = SIGSEGV; 465 ucode = SEGV_ACCERR; 466 } 467 } 468 addr = eva; 469 break; 470 471 case T_DIVIDE: /* integer divide fault */ 472 ucode = FPE_INTDIV; 473 i = SIGFPE; 474 break; 475 476 #ifdef DEV_ISA 477 case T_NMI: 478 #ifdef POWERFAIL_NMI 479 #ifndef TIMER_FREQ 480 # define TIMER_FREQ 1193182 481 #endif 482 if (time_second - lastalert > 10) { 483 log(LOG_WARNING, "NMI: power fail\n"); 484 sysbeep(880, hz); 485 lastalert = time_second; 486 } 487 goto userout; 488 #else /* !POWERFAIL_NMI */ 489 /* machine/parity/power fail/"kitchen sink" faults */ 490 if (isa_nmi(code) == 0) { 491 #ifdef KDB 492 /* 493 * NMI can be hooked up to a pushbutton 494 * for debugging. 495 */ 496 if (kdb_on_nmi) { 497 printf ("NMI ... going to debugger\n"); 498 kdb_trap(type, 0, frame); 499 } 500 #endif /* KDB */ 501 goto userout; 502 } else if (panic_on_nmi) 503 panic("NMI indicates hardware failure"); 504 break; 505 #endif /* POWERFAIL_NMI */ 506 #endif /* DEV_ISA */ 507 508 case T_OFLOW: /* integer overflow fault */ 509 ucode = FPE_INTOVF; 510 i = SIGFPE; 511 break; 512 513 case T_BOUND: /* bounds check fault */ 514 ucode = FPE_FLTSUB; 515 i = SIGFPE; 516 break; 517 518 case T_DNA: 519 #ifdef DEV_NPX 520 KASSERT(PCB_USER_FPU(td->td_pcb), 521 ("kernel FPU ctx has leaked")); 522 /* transparent fault (due to context switch "late") */ 523 if (npxdna()) 524 goto userout; 525 #endif 526 uprintf("pid %d killed due to lack of floating point\n", 527 p->p_pid); 528 i = SIGKILL; 529 ucode = 0; 530 break; 531 532 case T_FPOPFLT: /* FPU operand fetch fault */ 533 ucode = ILL_COPROC; 534 i = SIGILL; 535 break; 536 537 case T_XMMFLT: /* SIMD floating-point exception */ 538 #if defined(DEV_NPX) && !defined(CPU_DISABLE_SSE) && defined(I686_CPU) 539 ucode = npxtrap_sse(); 540 if (ucode == -1) 541 goto userout; 542 #else 543 ucode = 0; 544 #endif 545 i = SIGFPE; 546 break; 547 } 548 } else { 549 /* kernel trap */ 550 551 KASSERT(cold || td->td_ucred != NULL, 552 ("kernel trap doesn't have ucred")); 553 switch (type) { 554 case T_PAGEFLT: /* page fault */ 555 (void) trap_pfault(frame, FALSE, eva); 556 goto out; 557 558 case T_DNA: 559 #ifdef DEV_NPX 560 KASSERT(!PCB_USER_FPU(td->td_pcb), 561 ("Unregistered use of FPU in kernel")); 562 if (npxdna()) 563 goto out; 564 #endif 565 break; 566 567 case T_ARITHTRAP: /* arithmetic trap */ 568 case T_XMMFLT: /* SIMD floating-point exception */ 569 case T_FPOPFLT: /* FPU operand fetch fault */ 570 /* 571 * XXXKIB for now disable any FPU traps in kernel 572 * handler registration seems to be overkill 573 */ 574 trap_fatal(frame, 0); 575 goto out; 576 577 /* 578 * The following two traps can happen in 579 * vm86 mode, and, if so, we want to handle 580 * them specially. 581 */ 582 case T_PROTFLT: /* general protection fault */ 583 case T_STKFLT: /* stack fault */ 584 if (frame->tf_eflags & PSL_VM) { 585 i = vm86_emulate((struct vm86frame *)frame); 586 if (i != 0) 587 /* 588 * returns to original process 589 */ 590 vm86_trap((struct vm86frame *)frame); 591 goto out; 592 } 593 if (type == T_STKFLT) 594 break; 595 596 /* FALL THROUGH */ 597 598 case T_SEGNPFLT: /* segment not present fault */ 599 if (curpcb->pcb_flags & PCB_VM86CALL) 600 break; 601 602 /* 603 * Invalid %fs's and %gs's can be created using 604 * procfs or PT_SETREGS or by invalidating the 605 * underlying LDT entry. This causes a fault 606 * in kernel mode when the kernel attempts to 607 * switch contexts. Lose the bad context 608 * (XXX) so that we can continue, and generate 609 * a signal. 610 */ 611 if (frame->tf_eip == (int)cpu_switch_load_gs) { 612 curpcb->pcb_gs = 0; 613 #if 0 614 PROC_LOCK(p); 615 kern_psignal(p, SIGBUS); 616 PROC_UNLOCK(p); 617 #endif 618 goto out; 619 } 620 621 if (td->td_intr_nesting_level != 0) 622 break; 623 624 /* 625 * Invalid segment selectors and out of bounds 626 * %eip's and %esp's can be set up in user mode. 627 * This causes a fault in kernel mode when the 628 * kernel tries to return to user mode. We want 629 * to get this fault so that we can fix the 630 * problem here and not have to check all the 631 * selectors and pointers when the user changes 632 * them. 633 */ 634 if (frame->tf_eip == (int)doreti_iret) { 635 frame->tf_eip = (int)doreti_iret_fault; 636 goto out; 637 } 638 if (frame->tf_eip == (int)doreti_popl_ds) { 639 frame->tf_eip = (int)doreti_popl_ds_fault; 640 goto out; 641 } 642 if (frame->tf_eip == (int)doreti_popl_es) { 643 frame->tf_eip = (int)doreti_popl_es_fault; 644 goto out; 645 } 646 if (frame->tf_eip == (int)doreti_popl_fs) { 647 frame->tf_eip = (int)doreti_popl_fs_fault; 648 goto out; 649 } 650 if (curpcb->pcb_onfault != NULL) { 651 frame->tf_eip = 652 (int)curpcb->pcb_onfault; 653 goto out; 654 } 655 break; 656 657 case T_TSSFLT: 658 /* 659 * PSL_NT can be set in user mode and isn't cleared 660 * automatically when the kernel is entered. This 661 * causes a TSS fault when the kernel attempts to 662 * `iret' because the TSS link is uninitialized. We 663 * want to get this fault so that we can fix the 664 * problem here and not every time the kernel is 665 * entered. 666 */ 667 if (frame->tf_eflags & PSL_NT) { 668 frame->tf_eflags &= ~PSL_NT; 669 goto out; 670 } 671 break; 672 673 case T_TRCTRAP: /* trace trap */ 674 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) { 675 /* 676 * We've just entered system mode via the 677 * syscall lcall. Continue single stepping 678 * silently until the syscall handler has 679 * saved the flags. 680 */ 681 goto out; 682 } 683 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 684 /* 685 * The syscall handler has now saved the 686 * flags. Stop single stepping it. 687 */ 688 frame->tf_eflags &= ~PSL_T; 689 goto out; 690 } 691 /* 692 * Ignore debug register trace traps due to 693 * accesses in the user's address space, which 694 * can happen under several conditions such as 695 * if a user sets a watchpoint on a buffer and 696 * then passes that buffer to a system call. 697 * We still want to get TRCTRAPS for addresses 698 * in kernel space because that is useful when 699 * debugging the kernel. 700 */ 701 if (user_dbreg_trap() && 702 !(curpcb->pcb_flags & PCB_VM86CALL)) { 703 /* 704 * Reset breakpoint bits because the 705 * processor doesn't 706 */ 707 load_dr6(rdr6() & 0xfffffff0); 708 goto out; 709 } 710 /* 711 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 712 */ 713 case T_BPTFLT: 714 /* 715 * If KDB is enabled, let it handle the debugger trap. 716 * Otherwise, debugger traps "can't happen". 717 */ 718 #ifdef KDB 719 if (kdb_trap(type, 0, frame)) 720 goto out; 721 #endif 722 break; 723 724 #ifdef DEV_ISA 725 case T_NMI: 726 #ifdef POWERFAIL_NMI 727 if (time_second - lastalert > 10) { 728 log(LOG_WARNING, "NMI: power fail\n"); 729 sysbeep(880, hz); 730 lastalert = time_second; 731 } 732 goto out; 733 #else /* !POWERFAIL_NMI */ 734 /* machine/parity/power fail/"kitchen sink" faults */ 735 if (isa_nmi(code) == 0) { 736 #ifdef KDB 737 /* 738 * NMI can be hooked up to a pushbutton 739 * for debugging. 740 */ 741 if (kdb_on_nmi) { 742 printf ("NMI ... going to debugger\n"); 743 kdb_trap(type, 0, frame); 744 } 745 #endif /* KDB */ 746 goto out; 747 } else if (panic_on_nmi == 0) 748 goto out; 749 /* FALLTHROUGH */ 750 #endif /* POWERFAIL_NMI */ 751 #endif /* DEV_ISA */ 752 } 753 754 trap_fatal(frame, eva); 755 goto out; 756 } 757 758 /* Translate fault for emulators (e.g. Linux) */ 759 if (*p->p_sysent->sv_transtrap) 760 i = (*p->p_sysent->sv_transtrap)(i, type); 761 762 ksiginfo_init_trap(&ksi); 763 ksi.ksi_signo = i; 764 ksi.ksi_code = ucode; 765 ksi.ksi_addr = (void *)addr; 766 ksi.ksi_trapno = type; 767 if (uprintf_signal) { 768 uprintf("pid %d comm %s: signal %d err %x code %d type %d " 769 "addr 0x%x esp 0x%08x eip 0x%08x " 770 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 771 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 772 frame->tf_esp, frame->tf_eip, 773 fubyte((void *)(frame->tf_eip + 0)), 774 fubyte((void *)(frame->tf_eip + 1)), 775 fubyte((void *)(frame->tf_eip + 2)), 776 fubyte((void *)(frame->tf_eip + 3)), 777 fubyte((void *)(frame->tf_eip + 4)), 778 fubyte((void *)(frame->tf_eip + 5)), 779 fubyte((void *)(frame->tf_eip + 6)), 780 fubyte((void *)(frame->tf_eip + 7))); 781 } 782 KASSERT((read_eflags() & PSL_I) != 0, ("interrupts disabled")); 783 trapsignal(td, &ksi); 784 785 #ifdef DEBUG 786 if (type <= MAX_TRAP_MSG) { 787 uprintf("fatal process exception: %s", 788 trap_msg[type]); 789 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 790 uprintf(", fault VA = 0x%lx", (u_long)eva); 791 uprintf("\n"); 792 } 793 #endif 794 795 user: 796 userret(td, frame); 797 mtx_assert(&Giant, MA_NOTOWNED); 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 = NULL; 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. 884 * vm is initialized above to NULL. If curproc is NULL 885 * or curproc->p_vmspace is NULL the fault is fatal. 886 */ 887 if (p != NULL) 888 vm = p->p_vmspace; 889 890 if (vm == NULL) 891 goto nogo; 892 893 map = &vm->vm_map; 894 if (!usermode && (td->td_intr_nesting_level != 0 || 895 curpcb->pcb_onfault == NULL)) { 896 trap_fatal(frame, eva); 897 return (-1); 898 } 899 } 900 901 /* 902 * PGEX_I is defined only if the execute disable bit capability is 903 * supported and enabled. 904 */ 905 if (frame->tf_err & PGEX_W) 906 ftype = VM_PROT_WRITE; 907 #ifdef PAE 908 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 909 ftype = VM_PROT_EXECUTE; 910 #endif 911 else 912 ftype = VM_PROT_READ; 913 914 if (map != kernel_map) { 915 /* 916 * Keep swapout from messing with us during this 917 * critical time. 918 */ 919 PROC_LOCK(p); 920 ++p->p_lock; 921 PROC_UNLOCK(p); 922 923 /* Fault in the user page: */ 924 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 925 926 PROC_LOCK(p); 927 --p->p_lock; 928 PROC_UNLOCK(p); 929 } else { 930 /* 931 * Don't have to worry about process locking or stacks in the 932 * kernel. 933 */ 934 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 935 } 936 if (rv == KERN_SUCCESS) { 937 #ifdef HWPMC_HOOKS 938 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 939 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 940 if (ftype == VM_PROT_READ) 941 PMC_SOFT_CALL_TF( , , page_fault, read, 942 frame); 943 else 944 PMC_SOFT_CALL_TF( , , page_fault, write, 945 frame); 946 } 947 #endif 948 return (0); 949 } 950 nogo: 951 if (!usermode) { 952 if (td->td_intr_nesting_level == 0 && 953 curpcb->pcb_onfault != NULL) { 954 frame->tf_eip = (int)curpcb->pcb_onfault; 955 return (0); 956 } 957 trap_fatal(frame, eva); 958 return (-1); 959 } 960 961 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 962 } 963 964 static void 965 trap_fatal(frame, eva) 966 struct trapframe *frame; 967 vm_offset_t eva; 968 { 969 int code, ss, esp; 970 u_int type; 971 struct soft_segment_descriptor softseg; 972 char *msg; 973 974 code = frame->tf_err; 975 type = frame->tf_trapno; 976 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 977 978 if (type <= MAX_TRAP_MSG) 979 msg = trap_msg[type]; 980 else 981 msg = "UNKNOWN"; 982 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 983 frame->tf_eflags & PSL_VM ? "vm86" : 984 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 985 #ifdef SMP 986 /* two separate prints in case of a trap on an unmapped page */ 987 printf("cpuid = %d; ", PCPU_GET(cpuid)); 988 printf("apic id = %02x\n", PCPU_GET(apic_id)); 989 #endif 990 if (type == T_PAGEFLT) { 991 printf("fault virtual address = 0x%x\n", eva); 992 printf("fault code = %s %s, %s\n", 993 code & PGEX_U ? "user" : "supervisor", 994 code & PGEX_W ? "write" : "read", 995 code & PGEX_P ? "protection violation" : "page not present"); 996 } 997 printf("instruction pointer = 0x%x:0x%x\n", 998 frame->tf_cs & 0xffff, frame->tf_eip); 999 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 1000 ss = frame->tf_ss & 0xffff; 1001 esp = frame->tf_esp; 1002 } else { 1003 ss = GSEL(GDATA_SEL, SEL_KPL); 1004 esp = (int)&frame->tf_esp; 1005 } 1006 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 1007 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 1008 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 1009 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 1010 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 1011 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 1012 softseg.ssd_gran); 1013 printf("processor eflags = "); 1014 if (frame->tf_eflags & PSL_T) 1015 printf("trace trap, "); 1016 if (frame->tf_eflags & PSL_I) 1017 printf("interrupt enabled, "); 1018 if (frame->tf_eflags & PSL_NT) 1019 printf("nested task, "); 1020 if (frame->tf_eflags & PSL_RF) 1021 printf("resume, "); 1022 if (frame->tf_eflags & PSL_VM) 1023 printf("vm86, "); 1024 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 1025 printf("current process = "); 1026 if (curproc) { 1027 printf("%lu (%s)\n", (u_long)curproc->p_pid, curthread->td_name); 1028 } else { 1029 printf("Idle\n"); 1030 } 1031 1032 #ifdef KDB 1033 if (debugger_on_panic || kdb_active) { 1034 frame->tf_err = eva; /* smuggle fault address to ddb */ 1035 if (kdb_trap(type, 0, frame)) { 1036 frame->tf_err = code; /* restore error code */ 1037 return; 1038 } 1039 frame->tf_err = code; /* restore error code */ 1040 } 1041 #endif 1042 printf("trap number = %d\n", type); 1043 if (type <= MAX_TRAP_MSG) 1044 panic("%s", trap_msg[type]); 1045 else 1046 panic("unknown/reserved trap"); 1047 } 1048 1049 /* 1050 * Double fault handler. Called when a fault occurs while writing 1051 * a frame for a trap/exception onto the stack. This usually occurs 1052 * when the stack overflows (such is the case with infinite recursion, 1053 * for example). 1054 * 1055 * XXX Note that the current PTD gets replaced by IdlePTD when the 1056 * task switch occurs. This means that the stack that was active at 1057 * the time of the double fault is not available at <kstack> unless 1058 * the machine was idle when the double fault occurred. The downside 1059 * of this is that "trace <ebp>" in ddb won't work. 1060 */ 1061 void 1062 dblfault_handler() 1063 { 1064 #ifdef KDTRACE_HOOKS 1065 if (dtrace_doubletrap_func != NULL) 1066 (*dtrace_doubletrap_func)(); 1067 #endif 1068 printf("\nFatal double fault:\n"); 1069 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 1070 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 1071 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 1072 #ifdef SMP 1073 /* two separate prints in case of a trap on an unmapped page */ 1074 printf("cpuid = %d; ", PCPU_GET(cpuid)); 1075 printf("apic id = %02x\n", PCPU_GET(apic_id)); 1076 #endif 1077 panic("double fault"); 1078 } 1079 1080 int 1081 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 1082 { 1083 struct proc *p; 1084 struct trapframe *frame; 1085 caddr_t params; 1086 int error; 1087 1088 p = td->td_proc; 1089 frame = td->td_frame; 1090 1091 params = (caddr_t)frame->tf_esp + sizeof(int); 1092 sa->code = frame->tf_eax; 1093 1094 /* 1095 * Need to check if this is a 32 bit or 64 bit syscall. 1096 */ 1097 if (sa->code == SYS_syscall) { 1098 /* 1099 * Code is first argument, followed by actual args. 1100 */ 1101 sa->code = fuword(params); 1102 params += sizeof(int); 1103 } else if (sa->code == SYS___syscall) { 1104 /* 1105 * Like syscall, but code is a quad, so as to maintain 1106 * quad alignment for the rest of the arguments. 1107 */ 1108 sa->code = fuword(params); 1109 params += sizeof(quad_t); 1110 } 1111 1112 if (p->p_sysent->sv_mask) 1113 sa->code &= p->p_sysent->sv_mask; 1114 if (sa->code >= p->p_sysent->sv_size) 1115 sa->callp = &p->p_sysent->sv_table[0]; 1116 else 1117 sa->callp = &p->p_sysent->sv_table[sa->code]; 1118 sa->narg = sa->callp->sy_narg; 1119 1120 if (params != NULL && sa->narg != 0) 1121 error = copyin(params, (caddr_t)sa->args, 1122 (u_int)(sa->narg * sizeof(int))); 1123 else 1124 error = 0; 1125 1126 if (error == 0) { 1127 td->td_retval[0] = 0; 1128 td->td_retval[1] = frame->tf_edx; 1129 } 1130 1131 return (error); 1132 } 1133 1134 #include "../../kern/subr_syscall.c" 1135 1136 /* 1137 * syscall - system call request C handler. A system call is 1138 * essentially treated as a trap by reusing the frame layout. 1139 */ 1140 void 1141 syscall(struct trapframe *frame) 1142 { 1143 struct thread *td; 1144 struct syscall_args sa; 1145 register_t orig_tf_eflags; 1146 int error; 1147 ksiginfo_t ksi; 1148 1149 #ifdef DIAGNOSTIC 1150 if (ISPL(frame->tf_cs) != SEL_UPL) { 1151 panic("syscall"); 1152 /* NOT REACHED */ 1153 } 1154 #endif 1155 orig_tf_eflags = frame->tf_eflags; 1156 1157 td = curthread; 1158 td->td_frame = frame; 1159 1160 error = syscallenter(td, &sa); 1161 1162 /* 1163 * Traced syscall. 1164 */ 1165 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { 1166 frame->tf_eflags &= ~PSL_T; 1167 ksiginfo_init_trap(&ksi); 1168 ksi.ksi_signo = SIGTRAP; 1169 ksi.ksi_code = TRAP_TRACE; 1170 ksi.ksi_addr = (void *)frame->tf_eip; 1171 trapsignal(td, &ksi); 1172 } 1173 1174 KASSERT(PCB_USER_FPU(td->td_pcb), 1175 ("System call %s returning with kernel FPU ctx leaked", 1176 syscallname(td->td_proc, sa.code))); 1177 KASSERT(td->td_pcb->pcb_save == &td->td_pcb->pcb_user_save, 1178 ("System call %s returning with mangled pcb_save", 1179 syscallname(td->td_proc, sa.code))); 1180 1181 syscallret(td, error, &sa); 1182 }
Cache object: 5c062500b7b343cbb0c5d737550cee8a
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