trap.c revision 323143
1/*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the University of Utah, and William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 38 */ 39 40#include <sys/cdefs.h> 41__FBSDID("$FreeBSD: stable/11/sys/i386/i386/trap.c 323143 2017-09-03 09:14:06Z 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_stack.h" 53#include "opt_trap.h" 54 55#include <sys/param.h> 56#include <sys/bus.h> 57#include <sys/systm.h> 58#include <sys/proc.h> 59#include <sys/pioctl.h> 60#include <sys/ptrace.h> 61#include <sys/kdb.h> 62#include <sys/kernel.h> 63#include <sys/ktr.h> 64#include <sys/lock.h> 65#include <sys/mutex.h> 66#include <sys/resourcevar.h> 67#include <sys/signalvar.h> 68#include <sys/syscall.h> 69#include <sys/sysctl.h> 70#include <sys/sysent.h> 71#include <sys/uio.h> 72#include <sys/vmmeter.h> 73#ifdef HWPMC_HOOKS 74#include <sys/pmckern.h> 75PMC_SOFT_DEFINE( , , page_fault, all); 76PMC_SOFT_DEFINE( , , page_fault, read); 77PMC_SOFT_DEFINE( , , page_fault, write); 78#endif 79#include <security/audit/audit.h> 80 81#include <vm/vm.h> 82#include <vm/vm_param.h> 83#include <vm/pmap.h> 84#include <vm/vm_kern.h> 85#include <vm/vm_map.h> 86#include <vm/vm_page.h> 87#include <vm/vm_extern.h> 88 89#include <machine/cpu.h> 90#include <machine/intr_machdep.h> 91#include <x86/mca.h> 92#include <machine/md_var.h> 93#include <machine/pcb.h> 94#ifdef SMP 95#include <machine/smp.h> 96#endif 97#include <machine/stack.h> 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#endif 109 110void trap(struct trapframe *frame); 111void syscall(struct trapframe *frame); 112 113static int trap_pfault(struct trapframe *, int, vm_offset_t); 114static void trap_fatal(struct trapframe *, vm_offset_t); 115void dblfault_handler(void); 116 117extern inthand_t IDTVEC(lcall_syscall); 118 119#define MAX_TRAP_MSG 32 120static char *trap_msg[] = { 121 "", /* 0 unused */ 122 "privileged instruction fault", /* 1 T_PRIVINFLT */ 123 "", /* 2 unused */ 124 "breakpoint instruction fault", /* 3 T_BPTFLT */ 125 "", /* 4 unused */ 126 "", /* 5 unused */ 127 "arithmetic trap", /* 6 T_ARITHTRAP */ 128 "", /* 7 unused */ 129 "", /* 8 unused */ 130 "general protection fault", /* 9 T_PROTFLT */ 131 "trace trap", /* 10 T_TRCTRAP */ 132 "", /* 11 unused */ 133 "page fault", /* 12 T_PAGEFLT */ 134 "", /* 13 unused */ 135 "alignment fault", /* 14 T_ALIGNFLT */ 136 "", /* 15 unused */ 137 "", /* 16 unused */ 138 "", /* 17 unused */ 139 "integer divide fault", /* 18 T_DIVIDE */ 140 "non-maskable interrupt trap", /* 19 T_NMI */ 141 "overflow trap", /* 20 T_OFLOW */ 142 "FPU bounds check fault", /* 21 T_BOUND */ 143 "FPU device not available", /* 22 T_DNA */ 144 "double fault", /* 23 T_DOUBLEFLT */ 145 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 146 "invalid TSS fault", /* 25 T_TSSFLT */ 147 "segment not present fault", /* 26 T_SEGNPFLT */ 148 "stack fault", /* 27 T_STKFLT */ 149 "machine check trap", /* 28 T_MCHK */ 150 "SIMD floating-point exception", /* 29 T_XMMFLT */ 151 "reserved (unknown) fault", /* 30 T_RESERVED */ 152 "", /* 31 unused (reserved) */ 153 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 154}; 155 156#if defined(I586_CPU) && !defined(NO_F00F_HACK) 157int has_f00f_bug = 0; /* Initialized so that it can be patched. */ 158#endif 159 160static int prot_fault_translation = 0; 161SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 162 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 163static int uprintf_signal; 164SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW, 165 &uprintf_signal, 0, 166 "Print debugging information on trap signal to ctty"); 167 168/* 169 * Exception, fault, and trap interface to the FreeBSD kernel. 170 * This common code is called from assembly language IDT gate entry 171 * routines that prepare a suitable stack frame, and restore this 172 * frame after the exception has been processed. 173 */ 174 175void 176trap(struct trapframe *frame) 177{ 178#ifdef KDTRACE_HOOKS 179 struct reg regs; 180#endif 181 struct thread *td = curthread; 182 struct proc *p = td->td_proc; 183#ifdef KDB 184 register_t dr6; 185#endif 186 int i = 0, ucode = 0; 187 u_int type; 188 register_t addr = 0; 189 vm_offset_t eva; 190 ksiginfo_t ksi; 191#ifdef POWERFAIL_NMI 192 static int lastalert = 0; 193#endif 194 195 PCPU_INC(cnt.v_trap); 196 type = frame->tf_trapno; 197 198#ifdef SMP 199 /* Handler for NMI IPIs used for stopping CPUs. */ 200 if (type == T_NMI) { 201 if (ipi_nmi_handler() == 0) 202 goto out; 203 } 204#endif /* SMP */ 205 206#ifdef KDB 207 if (kdb_active) { 208 kdb_reenter(); 209 goto out; 210 } 211#endif 212 213 if (type == T_RESERVED) { 214 trap_fatal(frame, 0); 215 goto out; 216 } 217 218 if (type == T_NMI) { 219#ifdef HWPMC_HOOKS 220 /* 221 * CPU PMCs interrupt using an NMI so we check for that first. 222 * If the HWPMC module is active, 'pmc_hook' will point to 223 * the function to be called. A non-zero return value from the 224 * hook means that the NMI was consumed by it and that we can 225 * return immediately. 226 */ 227 if (pmc_intr != NULL && 228 (*pmc_intr)(PCPU_GET(cpuid), frame) != 0) 229 goto out; 230#endif 231 232#ifdef STACK 233 if (stack_nmi_handler(frame) != 0) 234 goto out; 235#endif 236 } 237 238 if (type == T_MCHK) { 239 mca_intr(); 240 goto out; 241 } 242 243#ifdef KDTRACE_HOOKS 244 /* 245 * A trap can occur while DTrace executes a probe. Before 246 * executing the probe, DTrace blocks re-scheduling and sets 247 * a flag in its per-cpu flags to indicate that it doesn't 248 * want to fault. On returning from the probe, the no-fault 249 * flag is cleared and finally re-scheduling is enabled. 250 */ 251 if ((type == T_PROTFLT || type == T_PAGEFLT) && 252 dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type)) 253 goto out; 254#endif 255 256 if ((frame->tf_eflags & PSL_I) == 0) { 257 /* 258 * Buggy application or kernel code has disabled 259 * interrupts and then trapped. Enabling interrupts 260 * now is wrong, but it is better than running with 261 * interrupts disabled until they are accidentally 262 * enabled later. 263 */ 264 if (TRAPF_USERMODE(frame) && 265 (curpcb->pcb_flags & PCB_VM86CALL) == 0) 266 uprintf( 267 "pid %ld (%s): trap %d with interrupts disabled\n", 268 (long)curproc->p_pid, curthread->td_name, type); 269 else if (type != T_NMI && type != T_BPTFLT && 270 type != T_TRCTRAP && 271 frame->tf_eip != (int)cpu_switch_load_gs) { 272 /* 273 * XXX not quite right, since this may be for a 274 * multiple fault in user mode. 275 */ 276 printf("kernel trap %d with interrupts disabled\n", 277 type); 278 /* 279 * Page faults need interrupts disabled until later, 280 * and we shouldn't enable interrupts while holding 281 * a spin lock. 282 */ 283 if (type != T_PAGEFLT && 284 td->td_md.md_spinlock_count == 0) 285 enable_intr(); 286 } 287 } 288 eva = 0; 289 if (type == T_PAGEFLT) { 290 /* 291 * For some Cyrix CPUs, %cr2 is clobbered by 292 * interrupts. This problem is worked around by using 293 * an interrupt gate for the pagefault handler. We 294 * are finally ready to read %cr2 and conditionally 295 * reenable interrupts. If we hold a spin lock, then 296 * we must not reenable interrupts. This might be a 297 * spurious page fault. 298 */ 299 eva = rcr2(); 300 if (td->td_md.md_spinlock_count == 0) 301 enable_intr(); 302 } 303 304 if (TRAPF_USERMODE(frame) && (curpcb->pcb_flags & PCB_VM86CALL) == 0) { 305 /* user trap */ 306 307 td->td_pticks = 0; 308 td->td_frame = frame; 309 addr = frame->tf_eip; 310 if (td->td_cowgen != p->p_cowgen) 311 thread_cow_update(td); 312 313 switch (type) { 314 case T_PRIVINFLT: /* privileged instruction fault */ 315 i = SIGILL; 316 ucode = ILL_PRVOPC; 317 break; 318 319 case T_BPTFLT: /* bpt instruction fault */ 320 case T_TRCTRAP: /* trace trap */ 321 enable_intr(); 322#ifdef KDTRACE_HOOKS 323 if (type == T_BPTFLT) { 324 fill_frame_regs(frame, ®s); 325 if (dtrace_pid_probe_ptr != NULL && 326 dtrace_pid_probe_ptr(®s) == 0) 327 goto out; 328 } 329#endif 330user_trctrap_out: 331 frame->tf_eflags &= ~PSL_T; 332 i = SIGTRAP; 333 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 334 break; 335 336 case T_ARITHTRAP: /* arithmetic trap */ 337 ucode = npxtrap_x87(); 338 if (ucode == -1) 339 goto userout; 340 i = SIGFPE; 341 break; 342 343 /* 344 * The following two traps can happen in 345 * vm86 mode, and, if so, we want to handle 346 * them specially. 347 */ 348 case T_PROTFLT: /* general protection fault */ 349 case T_STKFLT: /* stack fault */ 350 if (frame->tf_eflags & PSL_VM) { 351 i = vm86_emulate((struct vm86frame *)frame); 352 if (i == SIGTRAP) { 353 type = T_TRCTRAP; 354 load_dr6(rdr6() | 0x4000); 355 goto user_trctrap_out; 356 } 357 if (i == 0) 358 goto user; 359 break; 360 } 361 i = SIGBUS; 362 ucode = (type == T_PROTFLT) ? BUS_OBJERR : BUS_ADRERR; 363 break; 364 case T_SEGNPFLT: /* segment not present fault */ 365 i = SIGBUS; 366 ucode = BUS_ADRERR; 367 break; 368 case T_TSSFLT: /* invalid TSS fault */ 369 i = SIGBUS; 370 ucode = BUS_OBJERR; 371 break; 372 case T_ALIGNFLT: 373 i = SIGBUS; 374 ucode = BUS_ADRALN; 375 break; 376 case T_DOUBLEFLT: /* double fault */ 377 default: 378 i = SIGBUS; 379 ucode = BUS_OBJERR; 380 break; 381 382 case T_PAGEFLT: /* page fault */ 383 384 i = trap_pfault(frame, TRUE, eva); 385#if defined(I586_CPU) && !defined(NO_F00F_HACK) 386 if (i == -2) { 387 /* 388 * The f00f hack workaround has triggered, so 389 * treat the fault as an illegal instruction 390 * (T_PRIVINFLT) instead of a page fault. 391 */ 392 type = frame->tf_trapno = T_PRIVINFLT; 393 394 /* Proceed as in that case. */ 395 ucode = ILL_PRVOPC; 396 i = SIGILL; 397 break; 398 } 399#endif 400 if (i == -1) 401 goto userout; 402 if (i == 0) 403 goto user; 404 405 if (i == SIGSEGV) 406 ucode = SEGV_MAPERR; 407 else { 408 if (prot_fault_translation == 0) { 409 /* 410 * Autodetect. 411 * This check also covers the images 412 * without the ABI-tag ELF note. 413 */ 414 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 415 && p->p_osrel >= P_OSREL_SIGSEGV) { 416 i = SIGSEGV; 417 ucode = SEGV_ACCERR; 418 } else { 419 i = SIGBUS; 420 ucode = BUS_PAGE_FAULT; 421 } 422 } else if (prot_fault_translation == 1) { 423 /* 424 * Always compat mode. 425 */ 426 i = SIGBUS; 427 ucode = BUS_PAGE_FAULT; 428 } else { 429 /* 430 * Always SIGSEGV mode. 431 */ 432 i = SIGSEGV; 433 ucode = SEGV_ACCERR; 434 } 435 } 436 addr = eva; 437 break; 438 439 case T_DIVIDE: /* integer divide fault */ 440 ucode = FPE_INTDIV; 441 i = SIGFPE; 442 break; 443 444#ifdef DEV_ISA 445 case T_NMI: 446#ifdef POWERFAIL_NMI 447#ifndef TIMER_FREQ 448# define TIMER_FREQ 1193182 449#endif 450 if (time_second - lastalert > 10) { 451 log(LOG_WARNING, "NMI: power fail\n"); 452 sysbeep(880, hz); 453 lastalert = time_second; 454 } 455 goto userout; 456#else /* !POWERFAIL_NMI */ 457 nmi_handle_intr(type, frame); 458 goto out; 459#endif /* POWERFAIL_NMI */ 460#endif /* DEV_ISA */ 461 462 case T_OFLOW: /* integer overflow fault */ 463 ucode = FPE_INTOVF; 464 i = SIGFPE; 465 break; 466 467 case T_BOUND: /* bounds check fault */ 468 ucode = FPE_FLTSUB; 469 i = SIGFPE; 470 break; 471 472 case T_DNA: 473 KASSERT(PCB_USER_FPU(td->td_pcb), 474 ("kernel FPU ctx has leaked")); 475 /* transparent fault (due to context switch "late") */ 476 if (npxdna()) 477 goto userout; 478 uprintf("pid %d killed due to lack of floating point\n", 479 p->p_pid); 480 i = SIGKILL; 481 ucode = 0; 482 break; 483 484 case T_FPOPFLT: /* FPU operand fetch fault */ 485 ucode = ILL_COPROC; 486 i = SIGILL; 487 break; 488 489 case T_XMMFLT: /* SIMD floating-point exception */ 490 ucode = npxtrap_sse(); 491 if (ucode == -1) 492 goto userout; 493 i = SIGFPE; 494 break; 495#ifdef KDTRACE_HOOKS 496 case T_DTRACE_RET: 497 enable_intr(); 498 fill_frame_regs(frame, ®s); 499 if (dtrace_return_probe_ptr != NULL && 500 dtrace_return_probe_ptr(®s) == 0) 501 goto out; 502 goto userout; 503#endif 504 } 505 } else { 506 /* kernel trap */ 507 508 KASSERT(cold || td->td_ucred != NULL, 509 ("kernel trap doesn't have ucred")); 510 switch (type) { 511 case T_PAGEFLT: /* page fault */ 512 (void) trap_pfault(frame, FALSE, eva); 513 goto out; 514 515 case T_DNA: 516 if (PCB_USER_FPU(td->td_pcb)) 517 panic("Unregistered use of FPU in kernel"); 518 if (npxdna()) 519 goto out; 520 break; 521 522 case T_ARITHTRAP: /* arithmetic trap */ 523 case T_XMMFLT: /* SIMD floating-point exception */ 524 case T_FPOPFLT: /* FPU operand fetch fault */ 525 /* 526 * XXXKIB for now disable any FPU traps in kernel 527 * handler registration seems to be overkill 528 */ 529 trap_fatal(frame, 0); 530 goto out; 531 532 /* 533 * The following two traps can happen in 534 * vm86 mode, and, if so, we want to handle 535 * them specially. 536 */ 537 case T_PROTFLT: /* general protection fault */ 538 case T_STKFLT: /* stack fault */ 539 if (frame->tf_eflags & PSL_VM) { 540 i = vm86_emulate((struct vm86frame *)frame); 541 if (i == SIGTRAP) { 542 type = T_TRCTRAP; 543 load_dr6(rdr6() | 0x4000); 544 goto kernel_trctrap; 545 } 546 if (i != 0) 547 /* 548 * returns to original process 549 */ 550 vm86_trap((struct vm86frame *)frame); 551 goto out; 552 } 553 /* FALL THROUGH */ 554 case T_SEGNPFLT: /* segment not present fault */ 555 if (curpcb->pcb_flags & PCB_VM86CALL) 556 break; 557 558 /* 559 * Invalid %fs's and %gs's can be created using 560 * procfs or PT_SETREGS or by invalidating the 561 * underlying LDT entry. This causes a fault 562 * in kernel mode when the kernel attempts to 563 * switch contexts. Lose the bad context 564 * (XXX) so that we can continue, and generate 565 * a signal. 566 */ 567 if (frame->tf_eip == (int)cpu_switch_load_gs) { 568 curpcb->pcb_gs = 0; 569#if 0 570 PROC_LOCK(p); 571 kern_psignal(p, SIGBUS); 572 PROC_UNLOCK(p); 573#endif 574 goto out; 575 } 576 577 if (td->td_intr_nesting_level != 0) 578 break; 579 580 /* 581 * Invalid segment selectors and out of bounds 582 * %eip's and %esp's can be set up in user mode. 583 * This causes a fault in kernel mode when the 584 * kernel tries to return to user mode. We want 585 * to get this fault so that we can fix the 586 * problem here and not have to check all the 587 * selectors and pointers when the user changes 588 * them. 589 */ 590 if (frame->tf_eip == (int)doreti_iret) { 591 frame->tf_eip = (int)doreti_iret_fault; 592 goto out; 593 } 594 if (type == T_STKFLT) 595 break; 596 597 if (frame->tf_eip == (int)doreti_popl_ds) { 598 frame->tf_eip = (int)doreti_popl_ds_fault; 599 goto out; 600 } 601 if (frame->tf_eip == (int)doreti_popl_es) { 602 frame->tf_eip = (int)doreti_popl_es_fault; 603 goto out; 604 } 605 if (frame->tf_eip == (int)doreti_popl_fs) { 606 frame->tf_eip = (int)doreti_popl_fs_fault; 607 goto out; 608 } 609 if (curpcb->pcb_onfault != NULL) { 610 frame->tf_eip = 611 (int)curpcb->pcb_onfault; 612 goto out; 613 } 614 break; 615 616 case T_TSSFLT: 617 /* 618 * PSL_NT can be set in user mode and isn't cleared 619 * automatically when the kernel is entered. This 620 * causes a TSS fault when the kernel attempts to 621 * `iret' because the TSS link is uninitialized. We 622 * want to get this fault so that we can fix the 623 * problem here and not every time the kernel is 624 * entered. 625 */ 626 if (frame->tf_eflags & PSL_NT) { 627 frame->tf_eflags &= ~PSL_NT; 628 goto out; 629 } 630 break; 631 632 case T_TRCTRAP: /* trace trap */ 633kernel_trctrap: 634 if (frame->tf_eip == (int)IDTVEC(lcall_syscall)) { 635 /* 636 * We've just entered system mode via the 637 * syscall lcall. Continue single stepping 638 * silently until the syscall handler has 639 * saved the flags. 640 */ 641 goto out; 642 } 643 if (frame->tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 644 /* 645 * The syscall handler has now saved the 646 * flags. Stop single stepping it. 647 */ 648 frame->tf_eflags &= ~PSL_T; 649 goto out; 650 } 651 /* 652 * Ignore debug register trace traps due to 653 * accesses in the user's address space, which 654 * can happen under several conditions such as 655 * if a user sets a watchpoint on a buffer and 656 * then passes that buffer to a system call. 657 * We still want to get TRCTRAPS for addresses 658 * in kernel space because that is useful when 659 * debugging the kernel. 660 */ 661 if (user_dbreg_trap() && 662 !(curpcb->pcb_flags & PCB_VM86CALL)) { 663 /* 664 * Reset breakpoint bits because the 665 * processor doesn't 666 */ 667 load_dr6(rdr6() & ~0xf); 668 goto out; 669 } 670 /* 671 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 672 */ 673 case T_BPTFLT: 674 /* 675 * If KDB is enabled, let it handle the debugger trap. 676 * Otherwise, debugger traps "can't happen". 677 */ 678#ifdef KDB 679 /* XXX %dr6 is not quite reentrant. */ 680 dr6 = rdr6(); 681 load_dr6(dr6 & ~0x4000); 682 if (kdb_trap(type, dr6, frame)) 683 goto out; 684#endif 685 break; 686 687#ifdef DEV_ISA 688 case T_NMI: 689#ifdef POWERFAIL_NMI 690 if (time_second - lastalert > 10) { 691 log(LOG_WARNING, "NMI: power fail\n"); 692 sysbeep(880, hz); 693 lastalert = time_second; 694 } 695 goto out; 696#else /* !POWERFAIL_NMI */ 697 nmi_handle_intr(type, frame); 698 goto out; 699#endif /* POWERFAIL_NMI */ 700#endif /* DEV_ISA */ 701 } 702 703 trap_fatal(frame, eva); 704 goto out; 705 } 706 707 /* Translate fault for emulators (e.g. Linux) */ 708 if (*p->p_sysent->sv_transtrap) 709 i = (*p->p_sysent->sv_transtrap)(i, type); 710 711 ksiginfo_init_trap(&ksi); 712 ksi.ksi_signo = i; 713 ksi.ksi_code = ucode; 714 ksi.ksi_addr = (void *)addr; 715 ksi.ksi_trapno = type; 716 if (uprintf_signal) { 717 uprintf("pid %d comm %s: signal %d err %x code %d type %d " 718 "addr 0x%x esp 0x%08x eip 0x%08x " 719 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 720 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 721 frame->tf_esp, frame->tf_eip, 722 fubyte((void *)(frame->tf_eip + 0)), 723 fubyte((void *)(frame->tf_eip + 1)), 724 fubyte((void *)(frame->tf_eip + 2)), 725 fubyte((void *)(frame->tf_eip + 3)), 726 fubyte((void *)(frame->tf_eip + 4)), 727 fubyte((void *)(frame->tf_eip + 5)), 728 fubyte((void *)(frame->tf_eip + 6)), 729 fubyte((void *)(frame->tf_eip + 7))); 730 } 731 KASSERT((read_eflags() & PSL_I) != 0, ("interrupts disabled")); 732 trapsignal(td, &ksi); 733 734#ifdef DEBUG 735 if (type <= MAX_TRAP_MSG) { 736 uprintf("fatal process exception: %s", 737 trap_msg[type]); 738 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 739 uprintf(", fault VA = 0x%lx", (u_long)eva); 740 uprintf("\n"); 741 } 742#endif 743 744user: 745 userret(td, frame); 746 KASSERT(PCB_USER_FPU(td->td_pcb), 747 ("Return from trap with kernel FPU ctx leaked")); 748userout: 749out: 750 return; 751} 752 753static int 754trap_pfault(frame, usermode, eva) 755 struct trapframe *frame; 756 int usermode; 757 vm_offset_t eva; 758{ 759 vm_offset_t va; 760 vm_map_t map; 761 int rv = 0; 762 vm_prot_t ftype; 763 struct thread *td = curthread; 764 struct proc *p = td->td_proc; 765 766 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 767 /* 768 * Due to both processor errata and lazy TLB invalidation when 769 * access restrictions are removed from virtual pages, memory 770 * accesses that are allowed by the physical mapping layer may 771 * nonetheless cause one spurious page fault per virtual page. 772 * When the thread is executing a "no faulting" section that 773 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 774 * every page fault is treated as a spurious page fault, 775 * unless it accesses the same virtual address as the most 776 * recent page fault within the same "no faulting" section. 777 */ 778 if (td->td_md.md_spurflt_addr != eva || 779 (td->td_pflags & TDP_RESETSPUR) != 0) { 780 /* 781 * Do nothing to the TLB. A stale TLB entry is 782 * flushed automatically by a page fault. 783 */ 784 td->td_md.md_spurflt_addr = eva; 785 td->td_pflags &= ~TDP_RESETSPUR; 786 return (0); 787 } 788 } else { 789 /* 790 * If we get a page fault while in a critical section, then 791 * it is most likely a fatal kernel page fault. The kernel 792 * is already going to panic trying to get a sleep lock to 793 * do the VM lookup, so just consider it a fatal trap so the 794 * kernel can print out a useful trap message and even get 795 * to the debugger. 796 * 797 * If we get a page fault while holding a non-sleepable 798 * lock, then it is most likely a fatal kernel page fault. 799 * If WITNESS is enabled, then it's going to whine about 800 * bogus LORs with various VM locks, so just skip to the 801 * fatal trap handling directly. 802 */ 803 if (td->td_critnest != 0 || 804 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 805 "Kernel page fault") != 0) { 806 trap_fatal(frame, eva); 807 return (-1); 808 } 809 } 810 va = trunc_page(eva); 811 if (va >= KERNBASE) { 812 /* 813 * Don't allow user-mode faults in kernel address space. 814 * An exception: if the faulting address is the invalid 815 * instruction entry in the IDT, then the Intel Pentium 816 * F00F bug workaround was triggered, and we need to 817 * treat it is as an illegal instruction, and not a page 818 * fault. 819 */ 820#if defined(I586_CPU) && !defined(NO_F00F_HACK) 821 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) 822 return (-2); 823#endif 824 if (usermode) 825 goto nogo; 826 827 map = kernel_map; 828 } else { 829 map = &p->p_vmspace->vm_map; 830 831 /* 832 * When accessing a user-space address, kernel must be 833 * ready to accept the page fault, and provide a 834 * handling routine. Since accessing the address 835 * without the handler is a bug, do not try to handle 836 * it normally, and panic immediately. 837 */ 838 if (!usermode && (td->td_intr_nesting_level != 0 || 839 curpcb->pcb_onfault == NULL)) { 840 trap_fatal(frame, eva); 841 return (-1); 842 } 843 } 844 845 /* 846 * If the trap was caused by errant bits in the PTE then panic. 847 */ 848 if (frame->tf_err & PGEX_RSV) { 849 trap_fatal(frame, eva); 850 return (-1); 851 } 852 853 /* 854 * PGEX_I is defined only if the execute disable bit capability is 855 * supported and enabled. 856 */ 857 if (frame->tf_err & PGEX_W) 858 ftype = VM_PROT_WRITE; 859#if defined(PAE) || defined(PAE_TABLES) 860 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 861 ftype = VM_PROT_EXECUTE; 862#endif 863 else 864 ftype = VM_PROT_READ; 865 866 /* Fault in the page. */ 867 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 868 if (rv == KERN_SUCCESS) { 869#ifdef HWPMC_HOOKS 870 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 871 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 872 if (ftype == VM_PROT_READ) 873 PMC_SOFT_CALL_TF( , , page_fault, read, 874 frame); 875 else 876 PMC_SOFT_CALL_TF( , , page_fault, write, 877 frame); 878 } 879#endif 880 return (0); 881 } 882nogo: 883 if (!usermode) { 884 if (td->td_intr_nesting_level == 0 && 885 curpcb->pcb_onfault != NULL) { 886 frame->tf_eip = (int)curpcb->pcb_onfault; 887 return (0); 888 } 889 trap_fatal(frame, eva); 890 return (-1); 891 } 892 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 893} 894 895static void 896trap_fatal(frame, eva) 897 struct trapframe *frame; 898 vm_offset_t eva; 899{ 900 int code, ss, esp; 901 u_int type; 902 struct soft_segment_descriptor softseg; 903 char *msg; 904 905 code = frame->tf_err; 906 type = frame->tf_trapno; 907 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 908 909 if (type <= MAX_TRAP_MSG) 910 msg = trap_msg[type]; 911 else 912 msg = "UNKNOWN"; 913 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 914 frame->tf_eflags & PSL_VM ? "vm86" : 915 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 916#ifdef SMP 917 /* two separate prints in case of a trap on an unmapped page */ 918 printf("cpuid = %d; ", PCPU_GET(cpuid)); 919 printf("apic id = %02x\n", PCPU_GET(apic_id)); 920#endif 921 if (type == T_PAGEFLT) { 922 printf("fault virtual address = 0x%x\n", eva); 923 printf("fault code = %s %s%s, %s\n", 924 code & PGEX_U ? "user" : "supervisor", 925 code & PGEX_W ? "write" : "read", 926#if defined(PAE) || defined(PAE_TABLES) 927 pg_nx != 0 ? 928 (code & PGEX_I ? " instruction" : " data") : 929#endif 930 "", 931 code & PGEX_RSV ? "reserved bits in PTE" : 932 code & PGEX_P ? "protection violation" : "page not present"); 933 } 934 printf("instruction pointer = 0x%x:0x%x\n", 935 frame->tf_cs & 0xffff, frame->tf_eip); 936 if (TF_HAS_STACKREGS(frame)) { 937 ss = frame->tf_ss & 0xffff; 938 esp = frame->tf_esp; 939 } else { 940 ss = GSEL(GDATA_SEL, SEL_KPL); 941 esp = (int)&frame->tf_esp; 942 } 943 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 944 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 945 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 946 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 947 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 948 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 949 softseg.ssd_gran); 950 printf("processor eflags = "); 951 if (frame->tf_eflags & PSL_T) 952 printf("trace trap, "); 953 if (frame->tf_eflags & PSL_I) 954 printf("interrupt enabled, "); 955 if (frame->tf_eflags & PSL_NT) 956 printf("nested task, "); 957 if (frame->tf_eflags & PSL_RF) 958 printf("resume, "); 959 if (frame->tf_eflags & PSL_VM) 960 printf("vm86, "); 961 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 962 printf("current process = %d (%s)\n", 963 curproc->p_pid, curthread->td_name); 964 965#ifdef KDB 966 if (debugger_on_panic || kdb_active) { 967 frame->tf_err = eva; /* smuggle fault address to ddb */ 968 if (kdb_trap(type, 0, frame)) { 969 frame->tf_err = code; /* restore error code */ 970 return; 971 } 972 frame->tf_err = code; /* restore error code */ 973 } 974#endif 975 printf("trap number = %d\n", type); 976 if (type <= MAX_TRAP_MSG) 977 panic("%s", trap_msg[type]); 978 else 979 panic("unknown/reserved trap"); 980} 981 982/* 983 * Double fault handler. Called when a fault occurs while writing 984 * a frame for a trap/exception onto the stack. This usually occurs 985 * when the stack overflows (such is the case with infinite recursion, 986 * for example). 987 * 988 * XXX Note that the current PTD gets replaced by IdlePTD when the 989 * task switch occurs. This means that the stack that was active at 990 * the time of the double fault is not available at <kstack> unless 991 * the machine was idle when the double fault occurred. The downside 992 * of this is that "trace <ebp>" in ddb won't work. 993 */ 994void 995dblfault_handler() 996{ 997#ifdef KDTRACE_HOOKS 998 if (dtrace_doubletrap_func != NULL) 999 (*dtrace_doubletrap_func)(); 1000#endif 1001 printf("\nFatal double fault:\n"); 1002 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 1003 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 1004 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 1005#ifdef SMP 1006 /* two separate prints in case of a trap on an unmapped page */ 1007 printf("cpuid = %d; ", PCPU_GET(cpuid)); 1008 printf("apic id = %02x\n", PCPU_GET(apic_id)); 1009#endif 1010 panic("double fault"); 1011} 1012 1013int 1014cpu_fetch_syscall_args(struct thread *td) 1015{ 1016 struct proc *p; 1017 struct trapframe *frame; 1018 struct syscall_args *sa; 1019 caddr_t params; 1020 long tmp; 1021 int error; 1022 1023 p = td->td_proc; 1024 frame = td->td_frame; 1025 sa = &td->td_sa; 1026 1027 params = (caddr_t)frame->tf_esp + sizeof(int); 1028 sa->code = frame->tf_eax; 1029 1030 /* 1031 * Need to check if this is a 32 bit or 64 bit syscall. 1032 */ 1033 if (sa->code == SYS_syscall) { 1034 /* 1035 * Code is first argument, followed by actual args. 1036 */ 1037 error = fueword(params, &tmp); 1038 if (error == -1) 1039 return (EFAULT); 1040 sa->code = tmp; 1041 params += sizeof(int); 1042 } else if (sa->code == SYS___syscall) { 1043 /* 1044 * Like syscall, but code is a quad, so as to maintain 1045 * quad alignment for the rest of the arguments. 1046 */ 1047 error = fueword(params, &tmp); 1048 if (error == -1) 1049 return (EFAULT); 1050 sa->code = tmp; 1051 params += sizeof(quad_t); 1052 } 1053 1054 if (p->p_sysent->sv_mask) 1055 sa->code &= p->p_sysent->sv_mask; 1056 if (sa->code >= p->p_sysent->sv_size) 1057 sa->callp = &p->p_sysent->sv_table[0]; 1058 else 1059 sa->callp = &p->p_sysent->sv_table[sa->code]; 1060 sa->narg = sa->callp->sy_narg; 1061 1062 if (params != NULL && sa->narg != 0) 1063 error = copyin(params, (caddr_t)sa->args, 1064 (u_int)(sa->narg * sizeof(int))); 1065 else 1066 error = 0; 1067 1068 if (error == 0) { 1069 td->td_retval[0] = 0; 1070 td->td_retval[1] = frame->tf_edx; 1071 } 1072 1073 return (error); 1074} 1075 1076#include "../../kern/subr_syscall.c" 1077 1078/* 1079 * syscall - system call request C handler. A system call is 1080 * essentially treated as a trap by reusing the frame layout. 1081 */ 1082void 1083syscall(struct trapframe *frame) 1084{ 1085 struct thread *td; 1086 register_t orig_tf_eflags; 1087 int error; 1088 ksiginfo_t ksi; 1089 1090#ifdef DIAGNOSTIC 1091 if (!(TRAPF_USERMODE(frame) && 1092 (curpcb->pcb_flags & PCB_VM86CALL) == 0)) { 1093 panic("syscall"); 1094 /* NOT REACHED */ 1095 } 1096#endif 1097 orig_tf_eflags = frame->tf_eflags; 1098 1099 td = curthread; 1100 td->td_frame = frame; 1101 1102 error = syscallenter(td); 1103 1104 /* 1105 * Traced syscall. 1106 */ 1107 if ((orig_tf_eflags & PSL_T) && !(orig_tf_eflags & PSL_VM)) { 1108 frame->tf_eflags &= ~PSL_T; 1109 ksiginfo_init_trap(&ksi); 1110 ksi.ksi_signo = SIGTRAP; 1111 ksi.ksi_code = TRAP_TRACE; 1112 ksi.ksi_addr = (void *)frame->tf_eip; 1113 trapsignal(td, &ksi); 1114 } 1115 1116 KASSERT(PCB_USER_FPU(td->td_pcb), 1117 ("System call %s returning with kernel FPU ctx leaked", 1118 syscallname(td->td_proc, td->td_sa.code))); 1119 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td), 1120 ("System call %s returning with mangled pcb_save", 1121 syscallname(td->td_proc, td->td_sa.code))); 1122 1123 syscallret(td, error); 1124} 1125