Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/trap.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
1 /*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the University of Utah, and William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 38 */ 39 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD: releng/11.0/sys/amd64/amd64/trap.c 300863 2016-05-27 18:45:11Z kib $"); 42 43 /* 44 * AMD64 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 54 #include <sys/param.h> 55 #include <sys/bus.h> 56 #include <sys/systm.h> 57 #include <sys/proc.h> 58 #include <sys/pioctl.h> 59 #include <sys/ptrace.h> 60 #include <sys/kdb.h> 61 #include <sys/kernel.h> 62 #include <sys/ktr.h> 63 #include <sys/lock.h> 64 #include <sys/mutex.h> 65 #include <sys/resourcevar.h> 66 #include <sys/signalvar.h> 67 #include <sys/syscall.h> 68 #include <sys/sysctl.h> 69 #include <sys/sysent.h> 70 #include <sys/uio.h> 71 #include <sys/vmmeter.h> 72 #ifdef HWPMC_HOOKS 73 #include <sys/pmckern.h> 74 PMC_SOFT_DEFINE( , , page_fault, all); 75 PMC_SOFT_DEFINE( , , page_fault, read); 76 PMC_SOFT_DEFINE( , , page_fault, write); 77 #endif 78 79 #include <vm/vm.h> 80 #include <vm/vm_param.h> 81 #include <vm/pmap.h> 82 #include <vm/vm_kern.h> 83 #include <vm/vm_map.h> 84 #include <vm/vm_page.h> 85 #include <vm/vm_extern.h> 86 87 #include <machine/cpu.h> 88 #include <machine/intr_machdep.h> 89 #include <x86/mca.h> 90 #include <machine/md_var.h> 91 #include <machine/pcb.h> 92 #ifdef SMP 93 #include <machine/smp.h> 94 #endif 95 #include <machine/stack.h> 96 #include <machine/tss.h> 97 98 #ifdef KDTRACE_HOOKS 99 #include <sys/dtrace_bsd.h> 100 #endif 101 102 extern void __noinline trap(struct trapframe *frame); 103 extern void trap_check(struct trapframe *frame); 104 extern void syscall(struct trapframe *frame); 105 void dblfault_handler(struct trapframe *frame); 106 107 static int trap_pfault(struct trapframe *, int); 108 static void trap_fatal(struct trapframe *, vm_offset_t); 109 110 #define MAX_TRAP_MSG 32 111 static char *trap_msg[] = { 112 "", /* 0 unused */ 113 "privileged instruction fault", /* 1 T_PRIVINFLT */ 114 "", /* 2 unused */ 115 "breakpoint instruction fault", /* 3 T_BPTFLT */ 116 "", /* 4 unused */ 117 "", /* 5 unused */ 118 "arithmetic trap", /* 6 T_ARITHTRAP */ 119 "", /* 7 unused */ 120 "", /* 8 unused */ 121 "general protection fault", /* 9 T_PROTFLT */ 122 "trace trap", /* 10 T_TRCTRAP */ 123 "", /* 11 unused */ 124 "page fault", /* 12 T_PAGEFLT */ 125 "", /* 13 unused */ 126 "alignment fault", /* 14 T_ALIGNFLT */ 127 "", /* 15 unused */ 128 "", /* 16 unused */ 129 "", /* 17 unused */ 130 "integer divide fault", /* 18 T_DIVIDE */ 131 "non-maskable interrupt trap", /* 19 T_NMI */ 132 "overflow trap", /* 20 T_OFLOW */ 133 "FPU bounds check fault", /* 21 T_BOUND */ 134 "FPU device not available", /* 22 T_DNA */ 135 "double fault", /* 23 T_DOUBLEFLT */ 136 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 137 "invalid TSS fault", /* 25 T_TSSFLT */ 138 "segment not present fault", /* 26 T_SEGNPFLT */ 139 "stack fault", /* 27 T_STKFLT */ 140 "machine check trap", /* 28 T_MCHK */ 141 "SIMD floating-point exception", /* 29 T_XMMFLT */ 142 "reserved (unknown) fault", /* 30 T_RESERVED */ 143 "", /* 31 unused (reserved) */ 144 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 145 }; 146 147 #ifdef KDB 148 static int kdb_on_nmi = 1; 149 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RWTUN, 150 &kdb_on_nmi, 0, "Go to KDB on NMI"); 151 #endif 152 static int panic_on_nmi = 1; 153 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RWTUN, 154 &panic_on_nmi, 0, "Panic on NMI"); 155 static int prot_fault_translation; 156 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RWTUN, 157 &prot_fault_translation, 0, 158 "Select signal to deliver on protection fault"); 159 static int uprintf_signal; 160 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RWTUN, 161 &uprintf_signal, 0, 162 "Print debugging information on trap signal to ctty"); 163 164 /* 165 * Exception, fault, and trap interface to the FreeBSD kernel. 166 * This common code is called from assembly language IDT gate entry 167 * routines that prepare a suitable stack frame, and restore this 168 * frame after the exception has been processed. 169 */ 170 171 void 172 trap(struct trapframe *frame) 173 { 174 #ifdef KDTRACE_HOOKS 175 struct reg regs; 176 #endif 177 struct thread *td = curthread; 178 struct proc *p = td->td_proc; 179 int i = 0, ucode = 0, code; 180 u_int type; 181 register_t addr = 0; 182 ksiginfo_t ksi; 183 184 PCPU_INC(cnt.v_trap); 185 type = frame->tf_trapno; 186 187 #ifdef SMP 188 /* Handler for NMI IPIs used for stopping CPUs. */ 189 if (type == T_NMI) { 190 if (ipi_nmi_handler() == 0) 191 goto out; 192 } 193 #endif /* SMP */ 194 195 #ifdef KDB 196 if (kdb_active) { 197 kdb_reenter(); 198 goto out; 199 } 200 #endif 201 202 if (type == T_RESERVED) { 203 trap_fatal(frame, 0); 204 goto out; 205 } 206 207 if (type == T_NMI) { 208 #ifdef HWPMC_HOOKS 209 /* 210 * CPU PMCs interrupt using an NMI. If the PMC module is 211 * active, pass the 'rip' value to the PMC module's interrupt 212 * handler. A non-zero return value from the handler means that 213 * the NMI was consumed by it and we can return immediately. 214 */ 215 if (pmc_intr != NULL && 216 (*pmc_intr)(PCPU_GET(cpuid), frame) != 0) 217 goto out; 218 #endif 219 220 #ifdef STACK 221 if (stack_nmi_handler(frame) != 0) 222 goto out; 223 #endif 224 } 225 226 if (type == T_MCHK) { 227 mca_intr(); 228 goto out; 229 } 230 231 if ((frame->tf_rflags & PSL_I) == 0) { 232 /* 233 * Buggy application or kernel code has disabled 234 * interrupts and then trapped. Enabling interrupts 235 * now is wrong, but it is better than running with 236 * interrupts disabled until they are accidentally 237 * enabled later. 238 */ 239 if (ISPL(frame->tf_cs) == SEL_UPL) 240 uprintf( 241 "pid %ld (%s): trap %d with interrupts disabled\n", 242 (long)curproc->p_pid, curthread->td_name, type); 243 else if (type != T_NMI && type != T_BPTFLT && 244 type != T_TRCTRAP) { 245 /* 246 * XXX not quite right, since this may be for a 247 * multiple fault in user mode. 248 */ 249 printf("kernel trap %d with interrupts disabled\n", 250 type); 251 252 /* 253 * We shouldn't enable interrupts while holding a 254 * spin lock. 255 */ 256 if (td->td_md.md_spinlock_count == 0) 257 enable_intr(); 258 } 259 } 260 261 code = frame->tf_err; 262 263 if (ISPL(frame->tf_cs) == SEL_UPL) { 264 /* user trap */ 265 266 td->td_pticks = 0; 267 td->td_frame = frame; 268 addr = frame->tf_rip; 269 if (td->td_cowgen != p->p_cowgen) 270 thread_cow_update(td); 271 272 switch (type) { 273 case T_PRIVINFLT: /* privileged instruction fault */ 274 i = SIGILL; 275 ucode = ILL_PRVOPC; 276 break; 277 278 case T_BPTFLT: /* bpt instruction fault */ 279 case T_TRCTRAP: /* trace trap */ 280 enable_intr(); 281 #ifdef KDTRACE_HOOKS 282 if (type == T_BPTFLT) { 283 fill_frame_regs(frame, ®s); 284 if (dtrace_pid_probe_ptr != NULL && 285 dtrace_pid_probe_ptr(®s) == 0) 286 goto out; 287 } 288 #endif 289 frame->tf_rflags &= ~PSL_T; 290 i = SIGTRAP; 291 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 292 break; 293 294 case T_ARITHTRAP: /* arithmetic trap */ 295 ucode = fputrap_x87(); 296 if (ucode == -1) 297 goto userout; 298 i = SIGFPE; 299 break; 300 301 case T_PROTFLT: /* general protection fault */ 302 i = SIGBUS; 303 ucode = BUS_OBJERR; 304 break; 305 case T_STKFLT: /* stack fault */ 306 case T_SEGNPFLT: /* segment not present fault */ 307 i = SIGBUS; 308 ucode = BUS_ADRERR; 309 break; 310 case T_TSSFLT: /* invalid TSS fault */ 311 i = SIGBUS; 312 ucode = BUS_OBJERR; 313 break; 314 case T_ALIGNFLT: 315 i = SIGBUS; 316 ucode = BUS_ADRALN; 317 break; 318 case T_DOUBLEFLT: /* double fault */ 319 default: 320 i = SIGBUS; 321 ucode = BUS_OBJERR; 322 break; 323 324 case T_PAGEFLT: /* page fault */ 325 /* 326 * Emulator can take care about this trap? 327 */ 328 if (*p->p_sysent->sv_trap != NULL && 329 (*p->p_sysent->sv_trap)(td) == 0) 330 goto userout; 331 332 addr = frame->tf_addr; 333 i = trap_pfault(frame, TRUE); 334 if (i == -1) 335 goto userout; 336 if (i == 0) 337 goto user; 338 339 if (i == SIGSEGV) 340 ucode = SEGV_MAPERR; 341 else { 342 if (prot_fault_translation == 0) { 343 /* 344 * Autodetect. 345 * This check also covers the images 346 * without the ABI-tag ELF note. 347 */ 348 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 349 && p->p_osrel >= P_OSREL_SIGSEGV) { 350 i = SIGSEGV; 351 ucode = SEGV_ACCERR; 352 } else { 353 i = SIGBUS; 354 ucode = BUS_PAGE_FAULT; 355 } 356 } else if (prot_fault_translation == 1) { 357 /* 358 * Always compat mode. 359 */ 360 i = SIGBUS; 361 ucode = BUS_PAGE_FAULT; 362 } else { 363 /* 364 * Always SIGSEGV mode. 365 */ 366 i = SIGSEGV; 367 ucode = SEGV_ACCERR; 368 } 369 } 370 break; 371 372 case T_DIVIDE: /* integer divide fault */ 373 ucode = FPE_INTDIV; 374 i = SIGFPE; 375 break; 376 377 #ifdef DEV_ISA 378 case T_NMI: 379 /* machine/parity/power fail/"kitchen sink" faults */ 380 if (isa_nmi(code) == 0) { 381 #ifdef KDB 382 /* 383 * NMI can be hooked up to a pushbutton 384 * for debugging. 385 */ 386 if (kdb_on_nmi) { 387 printf ("NMI ... going to debugger\n"); 388 kdb_trap(type, 0, frame); 389 } 390 #endif /* KDB */ 391 goto userout; 392 } else if (panic_on_nmi) 393 panic("NMI indicates hardware failure"); 394 break; 395 #endif /* DEV_ISA */ 396 397 case T_OFLOW: /* integer overflow fault */ 398 ucode = FPE_INTOVF; 399 i = SIGFPE; 400 break; 401 402 case T_BOUND: /* bounds check fault */ 403 ucode = FPE_FLTSUB; 404 i = SIGFPE; 405 break; 406 407 case T_DNA: 408 /* transparent fault (due to context switch "late") */ 409 KASSERT(PCB_USER_FPU(td->td_pcb), 410 ("kernel FPU ctx has leaked")); 411 fpudna(); 412 goto userout; 413 414 case T_FPOPFLT: /* FPU operand fetch fault */ 415 ucode = ILL_COPROC; 416 i = SIGILL; 417 break; 418 419 case T_XMMFLT: /* SIMD floating-point exception */ 420 ucode = fputrap_sse(); 421 if (ucode == -1) 422 goto userout; 423 i = SIGFPE; 424 break; 425 #ifdef KDTRACE_HOOKS 426 case T_DTRACE_RET: 427 enable_intr(); 428 fill_frame_regs(frame, ®s); 429 if (dtrace_return_probe_ptr != NULL && 430 dtrace_return_probe_ptr(®s) == 0) 431 goto out; 432 break; 433 #endif 434 } 435 } else { 436 /* kernel trap */ 437 438 KASSERT(cold || td->td_ucred != NULL, 439 ("kernel trap doesn't have ucred")); 440 switch (type) { 441 case T_PAGEFLT: /* page fault */ 442 (void) trap_pfault(frame, FALSE); 443 goto out; 444 445 case T_DNA: 446 KASSERT(!PCB_USER_FPU(td->td_pcb), 447 ("Unregistered use of FPU in kernel")); 448 fpudna(); 449 goto out; 450 451 case T_ARITHTRAP: /* arithmetic trap */ 452 case T_XMMFLT: /* SIMD floating-point exception */ 453 case T_FPOPFLT: /* FPU operand fetch fault */ 454 /* 455 * For now, supporting kernel handler 456 * registration for FPU traps is overkill. 457 */ 458 trap_fatal(frame, 0); 459 goto out; 460 461 case T_STKFLT: /* stack fault */ 462 case T_PROTFLT: /* general protection fault */ 463 case T_SEGNPFLT: /* segment not present fault */ 464 if (td->td_intr_nesting_level != 0) 465 break; 466 467 /* 468 * Invalid segment selectors and out of bounds 469 * %rip's and %rsp's can be set up in user mode. 470 * This causes a fault in kernel mode when the 471 * kernel tries to return to user mode. We want 472 * to get this fault so that we can fix the 473 * problem here and not have to check all the 474 * selectors and pointers when the user changes 475 * them. 476 */ 477 if (frame->tf_rip == (long)doreti_iret) { 478 frame->tf_rip = (long)doreti_iret_fault; 479 goto out; 480 } 481 if (frame->tf_rip == (long)ld_ds) { 482 frame->tf_rip = (long)ds_load_fault; 483 goto out; 484 } 485 if (frame->tf_rip == (long)ld_es) { 486 frame->tf_rip = (long)es_load_fault; 487 goto out; 488 } 489 if (frame->tf_rip == (long)ld_fs) { 490 frame->tf_rip = (long)fs_load_fault; 491 goto out; 492 } 493 if (frame->tf_rip == (long)ld_gs) { 494 frame->tf_rip = (long)gs_load_fault; 495 goto out; 496 } 497 if (frame->tf_rip == (long)ld_gsbase) { 498 frame->tf_rip = (long)gsbase_load_fault; 499 goto out; 500 } 501 if (frame->tf_rip == (long)ld_fsbase) { 502 frame->tf_rip = (long)fsbase_load_fault; 503 goto out; 504 } 505 if (curpcb->pcb_onfault != NULL) { 506 frame->tf_rip = (long)curpcb->pcb_onfault; 507 goto out; 508 } 509 break; 510 511 case T_TSSFLT: 512 /* 513 * PSL_NT can be set in user mode and isn't cleared 514 * automatically when the kernel is entered. This 515 * causes a TSS fault when the kernel attempts to 516 * `iret' because the TSS link is uninitialized. We 517 * want to get this fault so that we can fix the 518 * problem here and not every time the kernel is 519 * entered. 520 */ 521 if (frame->tf_rflags & PSL_NT) { 522 frame->tf_rflags &= ~PSL_NT; 523 goto out; 524 } 525 break; 526 527 case T_TRCTRAP: /* trace trap */ 528 /* 529 * Ignore debug register trace traps due to 530 * accesses in the user's address space, which 531 * can happen under several conditions such as 532 * if a user sets a watchpoint on a buffer and 533 * then passes that buffer to a system call. 534 * We still want to get TRCTRAPS for addresses 535 * in kernel space because that is useful when 536 * debugging the kernel. 537 */ 538 if (user_dbreg_trap()) { 539 /* 540 * Reset breakpoint bits because the 541 * processor doesn't 542 */ 543 /* XXX check upper bits here */ 544 load_dr6(rdr6() & 0xfffffff0); 545 goto out; 546 } 547 /* 548 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 549 */ 550 case T_BPTFLT: 551 /* 552 * If KDB is enabled, let it handle the debugger trap. 553 * Otherwise, debugger traps "can't happen". 554 */ 555 #ifdef KDB 556 if (kdb_trap(type, 0, frame)) 557 goto out; 558 #endif 559 break; 560 561 #ifdef DEV_ISA 562 case T_NMI: 563 /* machine/parity/power fail/"kitchen sink" faults */ 564 if (isa_nmi(code) == 0) { 565 #ifdef KDB 566 /* 567 * NMI can be hooked up to a pushbutton 568 * for debugging. 569 */ 570 if (kdb_on_nmi) { 571 printf ("NMI ... going to debugger\n"); 572 kdb_trap(type, 0, frame); 573 } 574 #endif /* KDB */ 575 goto out; 576 } else if (panic_on_nmi == 0) 577 goto out; 578 /* FALLTHROUGH */ 579 #endif /* DEV_ISA */ 580 } 581 582 trap_fatal(frame, 0); 583 goto out; 584 } 585 586 /* Translate fault for emulators (e.g. Linux) */ 587 if (*p->p_sysent->sv_transtrap) 588 i = (*p->p_sysent->sv_transtrap)(i, type); 589 590 ksiginfo_init_trap(&ksi); 591 ksi.ksi_signo = i; 592 ksi.ksi_code = ucode; 593 ksi.ksi_trapno = type; 594 ksi.ksi_addr = (void *)addr; 595 if (uprintf_signal) { 596 uprintf("pid %d comm %s: signal %d err %lx code %d type %d " 597 "addr 0x%lx rsp 0x%lx rip 0x%lx " 598 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 599 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 600 frame->tf_rsp, frame->tf_rip, 601 fubyte((void *)(frame->tf_rip + 0)), 602 fubyte((void *)(frame->tf_rip + 1)), 603 fubyte((void *)(frame->tf_rip + 2)), 604 fubyte((void *)(frame->tf_rip + 3)), 605 fubyte((void *)(frame->tf_rip + 4)), 606 fubyte((void *)(frame->tf_rip + 5)), 607 fubyte((void *)(frame->tf_rip + 6)), 608 fubyte((void *)(frame->tf_rip + 7))); 609 } 610 KASSERT((read_rflags() & PSL_I) != 0, ("interrupts disabled")); 611 trapsignal(td, &ksi); 612 613 user: 614 userret(td, frame); 615 KASSERT(PCB_USER_FPU(td->td_pcb), 616 ("Return from trap with kernel FPU ctx leaked")); 617 userout: 618 out: 619 return; 620 } 621 622 /* 623 * Ensure that we ignore any DTrace-induced faults. This function cannot 624 * be instrumented, so it cannot generate such faults itself. 625 */ 626 void 627 trap_check(struct trapframe *frame) 628 { 629 630 #ifdef KDTRACE_HOOKS 631 if (dtrace_trap_func != NULL && 632 (*dtrace_trap_func)(frame, frame->tf_trapno) != 0) 633 return; 634 #endif 635 trap(frame); 636 } 637 638 static int 639 trap_pfault(frame, usermode) 640 struct trapframe *frame; 641 int usermode; 642 { 643 vm_offset_t va; 644 vm_map_t map; 645 int rv = 0; 646 vm_prot_t ftype; 647 struct thread *td = curthread; 648 struct proc *p = td->td_proc; 649 vm_offset_t eva = frame->tf_addr; 650 651 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 652 /* 653 * Due to both processor errata and lazy TLB invalidation when 654 * access restrictions are removed from virtual pages, memory 655 * accesses that are allowed by the physical mapping layer may 656 * nonetheless cause one spurious page fault per virtual page. 657 * When the thread is executing a "no faulting" section that 658 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 659 * every page fault is treated as a spurious page fault, 660 * unless it accesses the same virtual address as the most 661 * recent page fault within the same "no faulting" section. 662 */ 663 if (td->td_md.md_spurflt_addr != eva || 664 (td->td_pflags & TDP_RESETSPUR) != 0) { 665 /* 666 * Do nothing to the TLB. A stale TLB entry is 667 * flushed automatically by a page fault. 668 */ 669 td->td_md.md_spurflt_addr = eva; 670 td->td_pflags &= ~TDP_RESETSPUR; 671 return (0); 672 } 673 } else { 674 /* 675 * If we get a page fault while in a critical section, then 676 * it is most likely a fatal kernel page fault. The kernel 677 * is already going to panic trying to get a sleep lock to 678 * do the VM lookup, so just consider it a fatal trap so the 679 * kernel can print out a useful trap message and even get 680 * to the debugger. 681 * 682 * If we get a page fault while holding a non-sleepable 683 * lock, then it is most likely a fatal kernel page fault. 684 * If WITNESS is enabled, then it's going to whine about 685 * bogus LORs with various VM locks, so just skip to the 686 * fatal trap handling directly. 687 */ 688 if (td->td_critnest != 0 || 689 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 690 "Kernel page fault") != 0) { 691 trap_fatal(frame, eva); 692 return (-1); 693 } 694 } 695 va = trunc_page(eva); 696 if (va >= VM_MIN_KERNEL_ADDRESS) { 697 /* 698 * Don't allow user-mode faults in kernel address space. 699 */ 700 if (usermode) 701 goto nogo; 702 703 map = kernel_map; 704 } else { 705 map = &p->p_vmspace->vm_map; 706 707 /* 708 * When accessing a usermode address, kernel must be 709 * ready to accept the page fault, and provide a 710 * handling routine. Since accessing the address 711 * without the handler is a bug, do not try to handle 712 * it normally, and panic immediately. 713 */ 714 if (!usermode && (td->td_intr_nesting_level != 0 || 715 curpcb->pcb_onfault == NULL)) { 716 trap_fatal(frame, eva); 717 return (-1); 718 } 719 } 720 721 /* 722 * If the trap was caused by errant bits in the PTE then panic. 723 */ 724 if (frame->tf_err & PGEX_RSV) { 725 trap_fatal(frame, eva); 726 return (-1); 727 } 728 729 /* 730 * PGEX_I is defined only if the execute disable bit capability is 731 * supported and enabled. 732 */ 733 if (frame->tf_err & PGEX_W) 734 ftype = VM_PROT_WRITE; 735 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 736 ftype = VM_PROT_EXECUTE; 737 else 738 ftype = VM_PROT_READ; 739 740 /* Fault in the page. */ 741 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 742 if (rv == KERN_SUCCESS) { 743 #ifdef HWPMC_HOOKS 744 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 745 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 746 if (ftype == VM_PROT_READ) 747 PMC_SOFT_CALL_TF( , , page_fault, read, 748 frame); 749 else 750 PMC_SOFT_CALL_TF( , , page_fault, write, 751 frame); 752 } 753 #endif 754 return (0); 755 } 756 nogo: 757 if (!usermode) { 758 if (td->td_intr_nesting_level == 0 && 759 curpcb->pcb_onfault != NULL) { 760 frame->tf_rip = (long)curpcb->pcb_onfault; 761 return (0); 762 } 763 trap_fatal(frame, eva); 764 return (-1); 765 } 766 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 767 } 768 769 static void 770 trap_fatal(frame, eva) 771 struct trapframe *frame; 772 vm_offset_t eva; 773 { 774 int code, ss; 775 u_int type; 776 long esp; 777 struct soft_segment_descriptor softseg; 778 char *msg; 779 780 code = frame->tf_err; 781 type = frame->tf_trapno; 782 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)], 783 &softseg); 784 785 if (type <= MAX_TRAP_MSG) 786 msg = trap_msg[type]; 787 else 788 msg = "UNKNOWN"; 789 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 790 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 791 #ifdef SMP 792 /* two separate prints in case of a trap on an unmapped page */ 793 printf("cpuid = %d; ", PCPU_GET(cpuid)); 794 printf("apic id = %02x\n", PCPU_GET(apic_id)); 795 #endif 796 if (type == T_PAGEFLT) { 797 printf("fault virtual address = 0x%lx\n", eva); 798 printf("fault code = %s %s %s%s, %s\n", 799 code & PGEX_U ? "user" : "supervisor", 800 code & PGEX_W ? "write" : "read", 801 code & PGEX_I ? "instruction" : "data", 802 code & PGEX_RSV ? " rsv" : "", 803 code & PGEX_P ? "protection violation" : "page not present"); 804 } 805 printf("instruction pointer = 0x%lx:0x%lx\n", 806 frame->tf_cs & 0xffff, frame->tf_rip); 807 if (ISPL(frame->tf_cs) == SEL_UPL) { 808 ss = frame->tf_ss & 0xffff; 809 esp = frame->tf_rsp; 810 } else { 811 ss = GSEL(GDATA_SEL, SEL_KPL); 812 esp = (long)&frame->tf_rsp; 813 } 814 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 815 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 816 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 817 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 818 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 819 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 820 softseg.ssd_gran); 821 printf("processor eflags = "); 822 if (frame->tf_rflags & PSL_T) 823 printf("trace trap, "); 824 if (frame->tf_rflags & PSL_I) 825 printf("interrupt enabled, "); 826 if (frame->tf_rflags & PSL_NT) 827 printf("nested task, "); 828 if (frame->tf_rflags & PSL_RF) 829 printf("resume, "); 830 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 831 printf("current process = %d (%s)\n", 832 curproc->p_pid, curthread->td_name); 833 834 #ifdef KDB 835 if (debugger_on_panic || kdb_active) 836 if (kdb_trap(type, 0, frame)) 837 return; 838 #endif 839 printf("trap number = %d\n", type); 840 if (type <= MAX_TRAP_MSG) 841 panic("%s", trap_msg[type]); 842 else 843 panic("unknown/reserved trap"); 844 } 845 846 /* 847 * Double fault handler. Called when a fault occurs while writing 848 * a frame for a trap/exception onto the stack. This usually occurs 849 * when the stack overflows (such is the case with infinite recursion, 850 * for example). 851 */ 852 void 853 dblfault_handler(struct trapframe *frame) 854 { 855 #ifdef KDTRACE_HOOKS 856 if (dtrace_doubletrap_func != NULL) 857 (*dtrace_doubletrap_func)(); 858 #endif 859 printf("\nFatal double fault\n"); 860 printf("rip = 0x%lx\n", frame->tf_rip); 861 printf("rsp = 0x%lx\n", frame->tf_rsp); 862 printf("rbp = 0x%lx\n", frame->tf_rbp); 863 #ifdef SMP 864 /* two separate prints in case of a trap on an unmapped page */ 865 printf("cpuid = %d; ", PCPU_GET(cpuid)); 866 printf("apic id = %02x\n", PCPU_GET(apic_id)); 867 #endif 868 panic("double fault"); 869 } 870 871 int 872 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 873 { 874 struct proc *p; 875 struct trapframe *frame; 876 register_t *argp; 877 caddr_t params; 878 int reg, regcnt, error; 879 880 p = td->td_proc; 881 frame = td->td_frame; 882 reg = 0; 883 regcnt = 6; 884 885 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 886 sa->code = frame->tf_rax; 887 888 if (sa->code == SYS_syscall || sa->code == SYS___syscall) { 889 sa->code = frame->tf_rdi; 890 reg++; 891 regcnt--; 892 } 893 if (p->p_sysent->sv_mask) 894 sa->code &= p->p_sysent->sv_mask; 895 896 if (sa->code >= p->p_sysent->sv_size) 897 sa->callp = &p->p_sysent->sv_table[0]; 898 else 899 sa->callp = &p->p_sysent->sv_table[sa->code]; 900 901 sa->narg = sa->callp->sy_narg; 902 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]), 903 ("Too many syscall arguments!")); 904 error = 0; 905 argp = &frame->tf_rdi; 906 argp += reg; 907 bcopy(argp, sa->args, sizeof(sa->args[0]) * regcnt); 908 if (sa->narg > regcnt) { 909 KASSERT(params != NULL, ("copyin args with no params!")); 910 error = copyin(params, &sa->args[regcnt], 911 (sa->narg - regcnt) * sizeof(sa->args[0])); 912 } 913 914 if (error == 0) { 915 td->td_retval[0] = 0; 916 td->td_retval[1] = frame->tf_rdx; 917 } 918 919 return (error); 920 } 921 922 #include "../../kern/subr_syscall.c" 923 924 /* 925 * System call handler for native binaries. The trap frame is already 926 * set up by the assembler trampoline and a pointer to it is saved in 927 * td_frame. 928 */ 929 void 930 amd64_syscall(struct thread *td, int traced) 931 { 932 struct syscall_args sa; 933 int error; 934 ksiginfo_t ksi; 935 936 #ifdef DIAGNOSTIC 937 if (ISPL(td->td_frame->tf_cs) != SEL_UPL) { 938 panic("syscall"); 939 /* NOT REACHED */ 940 } 941 #endif 942 error = syscallenter(td, &sa); 943 944 /* 945 * Traced syscall. 946 */ 947 if (__predict_false(traced)) { 948 td->td_frame->tf_rflags &= ~PSL_T; 949 ksiginfo_init_trap(&ksi); 950 ksi.ksi_signo = SIGTRAP; 951 ksi.ksi_code = TRAP_TRACE; 952 ksi.ksi_addr = (void *)td->td_frame->tf_rip; 953 trapsignal(td, &ksi); 954 } 955 956 KASSERT(PCB_USER_FPU(td->td_pcb), 957 ("System call %s returing with kernel FPU ctx leaked", 958 syscallname(td->td_proc, sa.code))); 959 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td), 960 ("System call %s returning with mangled pcb_save", 961 syscallname(td->td_proc, sa.code))); 962 KASSERT(td->td_md.md_invl_gen.gen == 0, 963 ("System call %s returning with leaked invl_gen %lu", 964 syscallname(td->td_proc, sa.code), td->td_md.md_invl_gen.gen)); 965 966 967 syscallret(td, error, &sa); 968 969 /* 970 * If the user-supplied value of %rip is not a canonical 971 * address, then some CPUs will trigger a ring 0 #GP during 972 * the sysret instruction. However, the fault handler would 973 * execute in ring 0 with the user's %gs and %rsp which would 974 * not be safe. Instead, use the full return path which 975 * catches the problem safely. 976 */ 977 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) 978 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 979 }
Cache object: 83356c8cc44ce4f3994c3d707c27a50a
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]