Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/trap.c
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1 /*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the University of Utah, and William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 38 */ 39 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 /* 44 * 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_kdtrace.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/tss.h> 96 97 #ifdef KDTRACE_HOOKS 98 #include <sys/dtrace_bsd.h> 99 100 /* 101 * This is a hook which is initialised by the dtrace module 102 * to handle traps which might occur during DTrace probe 103 * execution. 104 */ 105 dtrace_trap_func_t dtrace_trap_func; 106 107 dtrace_doubletrap_func_t dtrace_doubletrap_func; 108 109 /* 110 * This is a hook which is initialised by the systrace module 111 * when it is loaded. This keeps the DTrace syscall provider 112 * implementation opaque. 113 */ 114 systrace_probe_func_t systrace_probe_func; 115 116 /* 117 * These hooks are necessary for the pid and usdt providers. 118 */ 119 dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr; 120 dtrace_return_probe_ptr_t dtrace_return_probe_ptr; 121 #endif 122 123 extern void trap(struct trapframe *frame); 124 extern void syscall(struct trapframe *frame); 125 void dblfault_handler(struct trapframe *frame); 126 127 static int trap_pfault(struct trapframe *, int); 128 static void trap_fatal(struct trapframe *, vm_offset_t); 129 130 #define MAX_TRAP_MSG 32 131 static char *trap_msg[] = { 132 "", /* 0 unused */ 133 "privileged instruction fault", /* 1 T_PRIVINFLT */ 134 "", /* 2 unused */ 135 "breakpoint instruction fault", /* 3 T_BPTFLT */ 136 "", /* 4 unused */ 137 "", /* 5 unused */ 138 "arithmetic trap", /* 6 T_ARITHTRAP */ 139 "", /* 7 unused */ 140 "", /* 8 unused */ 141 "general protection fault", /* 9 T_PROTFLT */ 142 "trace trap", /* 10 T_TRCTRAP */ 143 "", /* 11 unused */ 144 "page fault", /* 12 T_PAGEFLT */ 145 "", /* 13 unused */ 146 "alignment fault", /* 14 T_ALIGNFLT */ 147 "", /* 15 unused */ 148 "", /* 16 unused */ 149 "", /* 17 unused */ 150 "integer divide fault", /* 18 T_DIVIDE */ 151 "non-maskable interrupt trap", /* 19 T_NMI */ 152 "overflow trap", /* 20 T_OFLOW */ 153 "FPU bounds check fault", /* 21 T_BOUND */ 154 "FPU device not available", /* 22 T_DNA */ 155 "double fault", /* 23 T_DOUBLEFLT */ 156 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 157 "invalid TSS fault", /* 25 T_TSSFLT */ 158 "segment not present fault", /* 26 T_SEGNPFLT */ 159 "stack fault", /* 27 T_STKFLT */ 160 "machine check trap", /* 28 T_MCHK */ 161 "SIMD floating-point exception", /* 29 T_XMMFLT */ 162 "reserved (unknown) fault", /* 30 T_RESERVED */ 163 "", /* 31 unused (reserved) */ 164 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 165 }; 166 167 #ifdef KDB 168 static int kdb_on_nmi = 1; 169 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 170 &kdb_on_nmi, 0, "Go to KDB on NMI"); 171 TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi); 172 #endif 173 static int panic_on_nmi = 1; 174 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 175 &panic_on_nmi, 0, "Panic on NMI"); 176 TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi); 177 static int prot_fault_translation; 178 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 179 &prot_fault_translation, 0, 180 "Select signal to deliver on protection fault"); 181 static int uprintf_signal; 182 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW, 183 &uprintf_signal, 0, 184 "Print debugging information on trap signal to ctty"); 185 186 /* 187 * Exception, fault, and trap interface to the FreeBSD kernel. 188 * This common code is called from assembly language IDT gate entry 189 * routines that prepare a suitable stack frame, and restore this 190 * frame after the exception has been processed. 191 */ 192 193 void 194 trap(struct trapframe *frame) 195 { 196 #ifdef KDTRACE_HOOKS 197 struct reg regs; 198 #endif 199 struct thread *td = curthread; 200 struct proc *p = td->td_proc; 201 int i = 0, ucode = 0, code; 202 u_int type; 203 register_t addr = 0; 204 ksiginfo_t ksi; 205 206 PCPU_INC(cnt.v_trap); 207 type = frame->tf_trapno; 208 209 #ifdef SMP 210 /* Handler for NMI IPIs used for stopping CPUs. */ 211 if (type == T_NMI) { 212 if (ipi_nmi_handler() == 0) 213 goto out; 214 } 215 #endif /* SMP */ 216 217 #ifdef KDB 218 if (kdb_active) { 219 kdb_reenter(); 220 goto out; 221 } 222 #endif 223 224 if (type == T_RESERVED) { 225 trap_fatal(frame, 0); 226 goto out; 227 } 228 229 #ifdef HWPMC_HOOKS 230 /* 231 * CPU PMCs interrupt using an NMI. If the PMC module is 232 * active, pass the 'rip' value to the PMC module's interrupt 233 * handler. A return value of '1' from the handler means that 234 * the NMI was handled by it and we can return immediately. 235 */ 236 if (type == T_NMI && pmc_intr && 237 (*pmc_intr)(PCPU_GET(cpuid), frame)) 238 goto out; 239 #endif 240 241 if (type == T_MCHK) { 242 mca_intr(); 243 goto out; 244 } 245 246 #ifdef KDTRACE_HOOKS 247 /* 248 * A trap can occur while DTrace executes a probe. Before 249 * executing the probe, DTrace blocks re-scheduling and sets 250 * a flag in its per-cpu flags to indicate that it doesn't 251 * want to fault. On returning from the probe, the no-fault 252 * flag is cleared and finally re-scheduling is enabled. 253 */ 254 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type)) 255 goto out; 256 #endif 257 258 if ((frame->tf_rflags & PSL_I) == 0) { 259 /* 260 * Buggy application or kernel code has disabled 261 * interrupts and then trapped. Enabling interrupts 262 * now is wrong, but it is better than running with 263 * interrupts disabled until they are accidentally 264 * enabled later. 265 */ 266 if (ISPL(frame->tf_cs) == SEL_UPL) 267 uprintf( 268 "pid %ld (%s): trap %d with interrupts disabled\n", 269 (long)curproc->p_pid, curthread->td_name, type); 270 else if (type != T_NMI && type != T_BPTFLT && 271 type != T_TRCTRAP) { 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 /* 280 * We shouldn't enable interrupts while holding a 281 * spin lock. 282 */ 283 if (td->td_md.md_spinlock_count == 0) 284 enable_intr(); 285 } 286 } 287 288 code = frame->tf_err; 289 290 if (ISPL(frame->tf_cs) == SEL_UPL) { 291 /* user trap */ 292 293 td->td_pticks = 0; 294 td->td_frame = frame; 295 addr = frame->tf_rip; 296 if (td->td_ucred != p->p_ucred) 297 cred_update_thread(td); 298 299 switch (type) { 300 case T_PRIVINFLT: /* privileged instruction fault */ 301 i = SIGILL; 302 ucode = ILL_PRVOPC; 303 break; 304 305 case T_BPTFLT: /* bpt instruction fault */ 306 case T_TRCTRAP: /* trace trap */ 307 enable_intr(); 308 #ifdef KDTRACE_HOOKS 309 if (type == T_BPTFLT) { 310 fill_frame_regs(frame, ®s); 311 if (dtrace_pid_probe_ptr != NULL && 312 dtrace_pid_probe_ptr(®s) == 0) 313 goto out; 314 } 315 #endif 316 frame->tf_rflags &= ~PSL_T; 317 i = SIGTRAP; 318 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 319 break; 320 321 case T_ARITHTRAP: /* arithmetic trap */ 322 ucode = fputrap_x87(); 323 if (ucode == -1) 324 goto userout; 325 i = SIGFPE; 326 break; 327 328 case T_PROTFLT: /* general protection fault */ 329 i = SIGBUS; 330 ucode = BUS_OBJERR; 331 break; 332 case T_STKFLT: /* stack fault */ 333 case T_SEGNPFLT: /* segment not present fault */ 334 i = SIGBUS; 335 ucode = BUS_ADRERR; 336 break; 337 case T_TSSFLT: /* invalid TSS fault */ 338 i = SIGBUS; 339 ucode = BUS_OBJERR; 340 break; 341 case T_ALIGNFLT: 342 i = SIGBUS; 343 ucode = BUS_ADRALN; 344 break; 345 case T_DOUBLEFLT: /* double fault */ 346 default: 347 i = SIGBUS; 348 ucode = BUS_OBJERR; 349 break; 350 351 case T_PAGEFLT: /* page fault */ 352 addr = frame->tf_addr; 353 i = trap_pfault(frame, TRUE); 354 if (i == -1) 355 goto userout; 356 if (i == 0) 357 goto user; 358 359 if (i == SIGSEGV) 360 ucode = SEGV_MAPERR; 361 else { 362 if (prot_fault_translation == 0) { 363 /* 364 * Autodetect. 365 * This check also covers the images 366 * without the ABI-tag ELF note. 367 */ 368 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 369 && p->p_osrel >= P_OSREL_SIGSEGV) { 370 i = SIGSEGV; 371 ucode = SEGV_ACCERR; 372 } else { 373 i = SIGBUS; 374 ucode = BUS_PAGE_FAULT; 375 } 376 } else if (prot_fault_translation == 1) { 377 /* 378 * Always compat mode. 379 */ 380 i = SIGBUS; 381 ucode = BUS_PAGE_FAULT; 382 } else { 383 /* 384 * Always SIGSEGV mode. 385 */ 386 i = SIGSEGV; 387 ucode = SEGV_ACCERR; 388 } 389 } 390 break; 391 392 case T_DIVIDE: /* integer divide fault */ 393 ucode = FPE_INTDIV; 394 i = SIGFPE; 395 break; 396 397 #ifdef DEV_ISA 398 case T_NMI: 399 /* machine/parity/power fail/"kitchen sink" faults */ 400 if (isa_nmi(code) == 0) { 401 #ifdef KDB 402 /* 403 * NMI can be hooked up to a pushbutton 404 * for debugging. 405 */ 406 if (kdb_on_nmi) { 407 printf ("NMI ... going to debugger\n"); 408 kdb_trap(type, 0, frame); 409 } 410 #endif /* KDB */ 411 goto userout; 412 } else if (panic_on_nmi) 413 panic("NMI indicates hardware failure"); 414 break; 415 #endif /* DEV_ISA */ 416 417 case T_OFLOW: /* integer overflow fault */ 418 ucode = FPE_INTOVF; 419 i = SIGFPE; 420 break; 421 422 case T_BOUND: /* bounds check fault */ 423 ucode = FPE_FLTSUB; 424 i = SIGFPE; 425 break; 426 427 case T_DNA: 428 /* transparent fault (due to context switch "late") */ 429 KASSERT(PCB_USER_FPU(td->td_pcb), 430 ("kernel FPU ctx has leaked")); 431 fpudna(); 432 goto userout; 433 434 case T_FPOPFLT: /* FPU operand fetch fault */ 435 ucode = ILL_COPROC; 436 i = SIGILL; 437 break; 438 439 case T_XMMFLT: /* SIMD floating-point exception */ 440 ucode = fputrap_sse(); 441 if (ucode == -1) 442 goto userout; 443 i = SIGFPE; 444 break; 445 #ifdef KDTRACE_HOOKS 446 case T_DTRACE_RET: 447 enable_intr(); 448 fill_frame_regs(frame, ®s); 449 if (dtrace_return_probe_ptr != NULL && 450 dtrace_return_probe_ptr(®s) == 0) 451 goto out; 452 break; 453 #endif 454 } 455 } else { 456 /* kernel trap */ 457 458 KASSERT(cold || td->td_ucred != NULL, 459 ("kernel trap doesn't have ucred")); 460 switch (type) { 461 case T_PAGEFLT: /* page fault */ 462 (void) trap_pfault(frame, FALSE); 463 goto out; 464 465 case T_DNA: 466 KASSERT(!PCB_USER_FPU(td->td_pcb), 467 ("Unregistered use of FPU in kernel")); 468 fpudna(); 469 goto out; 470 471 case T_ARITHTRAP: /* arithmetic trap */ 472 case T_XMMFLT: /* SIMD floating-point exception */ 473 case T_FPOPFLT: /* FPU operand fetch fault */ 474 /* 475 * XXXKIB for now disable any FPU traps in kernel 476 * handler registration seems to be overkill 477 */ 478 trap_fatal(frame, 0); 479 goto out; 480 481 case T_STKFLT: /* stack fault */ 482 case T_PROTFLT: /* general protection fault */ 483 case T_SEGNPFLT: /* segment not present fault */ 484 if (td->td_intr_nesting_level != 0) 485 break; 486 487 /* 488 * Invalid segment selectors and out of bounds 489 * %rip's and %rsp's can be set up in user mode. 490 * This causes a fault in kernel mode when the 491 * kernel tries to return to user mode. We want 492 * to get this fault so that we can fix the 493 * problem here and not have to check all the 494 * selectors and pointers when the user changes 495 * them. 496 */ 497 if (frame->tf_rip == (long)doreti_iret) { 498 frame->tf_rip = (long)doreti_iret_fault; 499 goto out; 500 } 501 if (frame->tf_rip == (long)ld_ds) { 502 frame->tf_rip = (long)ds_load_fault; 503 goto out; 504 } 505 if (frame->tf_rip == (long)ld_es) { 506 frame->tf_rip = (long)es_load_fault; 507 goto out; 508 } 509 if (frame->tf_rip == (long)ld_fs) { 510 frame->tf_rip = (long)fs_load_fault; 511 goto out; 512 } 513 if (frame->tf_rip == (long)ld_gs) { 514 frame->tf_rip = (long)gs_load_fault; 515 goto out; 516 } 517 if (frame->tf_rip == (long)ld_gsbase) { 518 frame->tf_rip = (long)gsbase_load_fault; 519 goto out; 520 } 521 if (frame->tf_rip == (long)ld_fsbase) { 522 frame->tf_rip = (long)fsbase_load_fault; 523 goto out; 524 } 525 if (curpcb->pcb_onfault != NULL) { 526 frame->tf_rip = (long)curpcb->pcb_onfault; 527 goto out; 528 } 529 break; 530 531 case T_TSSFLT: 532 /* 533 * PSL_NT can be set in user mode and isn't cleared 534 * automatically when the kernel is entered. This 535 * causes a TSS fault when the kernel attempts to 536 * `iret' because the TSS link is uninitialized. We 537 * want to get this fault so that we can fix the 538 * problem here and not every time the kernel is 539 * entered. 540 */ 541 if (frame->tf_rflags & PSL_NT) { 542 frame->tf_rflags &= ~PSL_NT; 543 goto out; 544 } 545 break; 546 547 case T_TRCTRAP: /* trace trap */ 548 /* 549 * Ignore debug register trace traps due to 550 * accesses in the user's address space, which 551 * can happen under several conditions such as 552 * if a user sets a watchpoint on a buffer and 553 * then passes that buffer to a system call. 554 * We still want to get TRCTRAPS for addresses 555 * in kernel space because that is useful when 556 * debugging the kernel. 557 */ 558 if (user_dbreg_trap()) { 559 /* 560 * Reset breakpoint bits because the 561 * processor doesn't 562 */ 563 /* XXX check upper bits here */ 564 load_dr6(rdr6() & 0xfffffff0); 565 goto out; 566 } 567 /* 568 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 569 */ 570 case T_BPTFLT: 571 /* 572 * If KDB is enabled, let it handle the debugger trap. 573 * Otherwise, debugger traps "can't happen". 574 */ 575 #ifdef KDB 576 if (kdb_trap(type, 0, frame)) 577 goto out; 578 #endif 579 break; 580 581 #ifdef DEV_ISA 582 case T_NMI: 583 /* machine/parity/power fail/"kitchen sink" faults */ 584 if (isa_nmi(code) == 0) { 585 #ifdef KDB 586 /* 587 * NMI can be hooked up to a pushbutton 588 * for debugging. 589 */ 590 if (kdb_on_nmi) { 591 printf ("NMI ... going to debugger\n"); 592 kdb_trap(type, 0, frame); 593 } 594 #endif /* KDB */ 595 goto out; 596 } else if (panic_on_nmi == 0) 597 goto out; 598 /* FALLTHROUGH */ 599 #endif /* DEV_ISA */ 600 } 601 602 trap_fatal(frame, 0); 603 goto out; 604 } 605 606 /* Translate fault for emulators (e.g. Linux) */ 607 if (*p->p_sysent->sv_transtrap) 608 i = (*p->p_sysent->sv_transtrap)(i, type); 609 610 ksiginfo_init_trap(&ksi); 611 ksi.ksi_signo = i; 612 ksi.ksi_code = ucode; 613 ksi.ksi_trapno = type; 614 ksi.ksi_addr = (void *)addr; 615 if (uprintf_signal) { 616 uprintf("pid %d comm %s: signal %d err %lx code %d type %d " 617 "addr 0x%lx rsp 0x%lx rip 0x%lx " 618 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 619 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 620 frame->tf_rsp, frame->tf_rip, 621 fubyte((void *)(frame->tf_rip + 0)), 622 fubyte((void *)(frame->tf_rip + 1)), 623 fubyte((void *)(frame->tf_rip + 2)), 624 fubyte((void *)(frame->tf_rip + 3)), 625 fubyte((void *)(frame->tf_rip + 4)), 626 fubyte((void *)(frame->tf_rip + 5)), 627 fubyte((void *)(frame->tf_rip + 6)), 628 fubyte((void *)(frame->tf_rip + 7))); 629 } 630 KASSERT((read_rflags() & PSL_I) != 0, ("interrupts disabled")); 631 trapsignal(td, &ksi); 632 633 user: 634 userret(td, frame); 635 mtx_assert(&Giant, MA_NOTOWNED); 636 KASSERT(PCB_USER_FPU(td->td_pcb), 637 ("Return from trap with kernel FPU ctx leaked")); 638 userout: 639 out: 640 return; 641 } 642 643 static int 644 trap_pfault(frame, usermode) 645 struct trapframe *frame; 646 int usermode; 647 { 648 vm_offset_t va; 649 struct vmspace *vm = NULL; 650 vm_map_t map; 651 int rv = 0; 652 vm_prot_t ftype; 653 struct thread *td = curthread; 654 struct proc *p = td->td_proc; 655 vm_offset_t eva = frame->tf_addr; 656 657 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 658 /* 659 * Due to both processor errata and lazy TLB invalidation when 660 * access restrictions are removed from virtual pages, memory 661 * accesses that are allowed by the physical mapping layer may 662 * nonetheless cause one spurious page fault per virtual page. 663 * When the thread is executing a "no faulting" section that 664 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 665 * every page fault is treated as a spurious page fault, 666 * unless it accesses the same virtual address as the most 667 * recent page fault within the same "no faulting" section. 668 */ 669 if (td->td_md.md_spurflt_addr != eva || 670 (td->td_pflags & TDP_RESETSPUR) != 0) { 671 /* 672 * Do nothing to the TLB. A stale TLB entry is 673 * flushed automatically by a page fault. 674 */ 675 td->td_md.md_spurflt_addr = eva; 676 td->td_pflags &= ~TDP_RESETSPUR; 677 return (0); 678 } 679 } else { 680 /* 681 * If we get a page fault while in a critical section, then 682 * it is most likely a fatal kernel page fault. The kernel 683 * is already going to panic trying to get a sleep lock to 684 * do the VM lookup, so just consider it a fatal trap so the 685 * kernel can print out a useful trap message and even get 686 * to the debugger. 687 * 688 * If we get a page fault while holding a non-sleepable 689 * lock, then it is most likely a fatal kernel page fault. 690 * If WITNESS is enabled, then it's going to whine about 691 * bogus LORs with various VM locks, so just skip to the 692 * fatal trap handling directly. 693 */ 694 if (td->td_critnest != 0 || 695 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 696 "Kernel page fault") != 0) { 697 trap_fatal(frame, eva); 698 return (-1); 699 } 700 } 701 va = trunc_page(eva); 702 if (va >= VM_MIN_KERNEL_ADDRESS) { 703 /* 704 * Don't allow user-mode faults in kernel address space. 705 */ 706 if (usermode) 707 goto nogo; 708 709 map = kernel_map; 710 } else { 711 /* 712 * This is a fault on non-kernel virtual memory. 713 * vm is initialized above to NULL. If curproc is NULL 714 * or curproc->p_vmspace is NULL the fault is fatal. 715 */ 716 if (p != NULL) 717 vm = p->p_vmspace; 718 719 if (vm == NULL) 720 goto nogo; 721 722 map = &vm->vm_map; 723 724 /* 725 * When accessing a usermode address, kernel must be 726 * ready to accept the page fault, and provide a 727 * handling routine. Since accessing the address 728 * without the handler is a bug, do not try to handle 729 * it normally, and panic immediately. 730 */ 731 if (!usermode && (td->td_intr_nesting_level != 0 || 732 curpcb->pcb_onfault == NULL)) { 733 trap_fatal(frame, eva); 734 return (-1); 735 } 736 } 737 738 /* 739 * PGEX_I is defined only if the execute disable bit capability is 740 * supported and enabled. 741 */ 742 if (frame->tf_err & PGEX_W) 743 ftype = VM_PROT_WRITE; 744 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 745 ftype = VM_PROT_EXECUTE; 746 else 747 ftype = VM_PROT_READ; 748 749 if (map != kernel_map) { 750 /* 751 * Keep swapout from messing with us during this 752 * critical time. 753 */ 754 PROC_LOCK(p); 755 ++p->p_lock; 756 PROC_UNLOCK(p); 757 758 /* Fault in the user page: */ 759 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 760 761 PROC_LOCK(p); 762 --p->p_lock; 763 PROC_UNLOCK(p); 764 } else { 765 /* 766 * Don't have to worry about process locking or stacks in the 767 * kernel. 768 */ 769 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 770 } 771 if (rv == KERN_SUCCESS) { 772 #ifdef HWPMC_HOOKS 773 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 774 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 775 if (ftype == VM_PROT_READ) 776 PMC_SOFT_CALL_TF( , , page_fault, read, 777 frame); 778 else 779 PMC_SOFT_CALL_TF( , , page_fault, write, 780 frame); 781 } 782 #endif 783 return (0); 784 } 785 nogo: 786 if (!usermode) { 787 if (td->td_intr_nesting_level == 0 && 788 curpcb->pcb_onfault != NULL) { 789 frame->tf_rip = (long)curpcb->pcb_onfault; 790 return (0); 791 } 792 if ((td->td_pflags & TDP_DEVMEMIO) != 0) { 793 KASSERT(curpcb->pcb_onfault != NULL, 794 ("/dev/mem without pcb_onfault")); 795 frame->tf_rip = (long)curpcb->pcb_onfault; 796 return (0); 797 } 798 trap_fatal(frame, eva); 799 return (-1); 800 } 801 802 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 803 } 804 805 static void 806 trap_fatal(frame, eva) 807 struct trapframe *frame; 808 vm_offset_t eva; 809 { 810 int code, ss; 811 u_int type; 812 long esp; 813 struct soft_segment_descriptor softseg; 814 char *msg; 815 816 code = frame->tf_err; 817 type = frame->tf_trapno; 818 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)], 819 &softseg); 820 821 if (type <= MAX_TRAP_MSG) 822 msg = trap_msg[type]; 823 else 824 msg = "UNKNOWN"; 825 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 826 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 827 #ifdef SMP 828 /* two separate prints in case of a trap on an unmapped page */ 829 printf("cpuid = %d; ", PCPU_GET(cpuid)); 830 printf("apic id = %02x\n", PCPU_GET(apic_id)); 831 #endif 832 if (type == T_PAGEFLT) { 833 printf("fault virtual address = 0x%lx\n", eva); 834 printf("fault code = %s %s %s, %s\n", 835 code & PGEX_U ? "user" : "supervisor", 836 code & PGEX_W ? "write" : "read", 837 code & PGEX_I ? "instruction" : "data", 838 code & PGEX_P ? "protection violation" : "page not present"); 839 } 840 printf("instruction pointer = 0x%lx:0x%lx\n", 841 frame->tf_cs & 0xffff, frame->tf_rip); 842 if (ISPL(frame->tf_cs) == SEL_UPL) { 843 ss = frame->tf_ss & 0xffff; 844 esp = frame->tf_rsp; 845 } else { 846 ss = GSEL(GDATA_SEL, SEL_KPL); 847 esp = (long)&frame->tf_rsp; 848 } 849 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 850 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 851 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 852 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 853 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 854 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 855 softseg.ssd_gran); 856 printf("processor eflags = "); 857 if (frame->tf_rflags & PSL_T) 858 printf("trace trap, "); 859 if (frame->tf_rflags & PSL_I) 860 printf("interrupt enabled, "); 861 if (frame->tf_rflags & PSL_NT) 862 printf("nested task, "); 863 if (frame->tf_rflags & PSL_RF) 864 printf("resume, "); 865 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 866 printf("current process = %d (%s)\n", 867 curproc->p_pid, curthread->td_name); 868 869 #ifdef KDB 870 if (debugger_on_panic || kdb_active) 871 if (kdb_trap(type, 0, frame)) 872 return; 873 #endif 874 printf("trap number = %d\n", type); 875 if (type <= MAX_TRAP_MSG) 876 panic("%s", trap_msg[type]); 877 else 878 panic("unknown/reserved trap"); 879 } 880 881 /* 882 * Double fault handler. Called when a fault occurs while writing 883 * a frame for a trap/exception onto the stack. This usually occurs 884 * when the stack overflows (such is the case with infinite recursion, 885 * for example). 886 */ 887 void 888 dblfault_handler(struct trapframe *frame) 889 { 890 #ifdef KDTRACE_HOOKS 891 if (dtrace_doubletrap_func != NULL) 892 (*dtrace_doubletrap_func)(); 893 #endif 894 printf("\nFatal double fault\n"); 895 printf("rip = 0x%lx\n", frame->tf_rip); 896 printf("rsp = 0x%lx\n", frame->tf_rsp); 897 printf("rbp = 0x%lx\n", frame->tf_rbp); 898 #ifdef SMP 899 /* two separate prints in case of a trap on an unmapped page */ 900 printf("cpuid = %d; ", PCPU_GET(cpuid)); 901 printf("apic id = %02x\n", PCPU_GET(apic_id)); 902 #endif 903 panic("double fault"); 904 } 905 906 int 907 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 908 { 909 struct proc *p; 910 struct trapframe *frame; 911 register_t *argp; 912 caddr_t params; 913 int reg, regcnt, error; 914 915 p = td->td_proc; 916 frame = td->td_frame; 917 reg = 0; 918 regcnt = 6; 919 920 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 921 sa->code = frame->tf_rax; 922 923 if (sa->code == SYS_syscall || sa->code == SYS___syscall) { 924 sa->code = frame->tf_rdi; 925 reg++; 926 regcnt--; 927 } 928 if (p->p_sysent->sv_mask) 929 sa->code &= p->p_sysent->sv_mask; 930 931 if (sa->code >= p->p_sysent->sv_size) 932 sa->callp = &p->p_sysent->sv_table[0]; 933 else 934 sa->callp = &p->p_sysent->sv_table[sa->code]; 935 936 sa->narg = sa->callp->sy_narg; 937 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]), 938 ("Too many syscall arguments!")); 939 error = 0; 940 argp = &frame->tf_rdi; 941 argp += reg; 942 bcopy(argp, sa->args, sizeof(sa->args[0]) * regcnt); 943 if (sa->narg > regcnt) { 944 KASSERT(params != NULL, ("copyin args with no params!")); 945 error = copyin(params, &sa->args[regcnt], 946 (sa->narg - regcnt) * sizeof(sa->args[0])); 947 } 948 949 if (error == 0) { 950 td->td_retval[0] = 0; 951 td->td_retval[1] = frame->tf_rdx; 952 } 953 954 return (error); 955 } 956 957 #include "../../kern/subr_syscall.c" 958 959 /* 960 * System call handler for native binaries. The trap frame is already 961 * set up by the assembler trampoline and a pointer to it is saved in 962 * td_frame. 963 */ 964 void 965 amd64_syscall(struct thread *td, int traced) 966 { 967 struct syscall_args sa; 968 int error; 969 ksiginfo_t ksi; 970 971 #ifdef DIAGNOSTIC 972 if (ISPL(td->td_frame->tf_cs) != SEL_UPL) { 973 panic("syscall"); 974 /* NOT REACHED */ 975 } 976 #endif 977 error = syscallenter(td, &sa); 978 979 /* 980 * Traced syscall. 981 */ 982 if (__predict_false(traced)) { 983 td->td_frame->tf_rflags &= ~PSL_T; 984 ksiginfo_init_trap(&ksi); 985 ksi.ksi_signo = SIGTRAP; 986 ksi.ksi_code = TRAP_TRACE; 987 ksi.ksi_addr = (void *)td->td_frame->tf_rip; 988 trapsignal(td, &ksi); 989 } 990 991 KASSERT(PCB_USER_FPU(td->td_pcb), 992 ("System call %s returing with kernel FPU ctx leaked", 993 syscallname(td->td_proc, sa.code))); 994 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td), 995 ("System call %s returning with mangled pcb_save", 996 syscallname(td->td_proc, sa.code))); 997 998 syscallret(td, error, &sa); 999 1000 /* 1001 * If the user-supplied value of %rip is not a canonical 1002 * address, then some CPUs will trigger a ring 0 #GP during 1003 * the sysret instruction. However, the fault handler would 1004 * execute in ring 0 with the user's %gs and %rsp which would 1005 * not be safe. Instead, use the full return path which 1006 * catches the problem safely. 1007 */ 1008 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) 1009 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 1010 }
Cache object: 58e0538c792cd609061ca744efd21f9a
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