Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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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: releng/9.1/sys/amd64/amd64/trap.c 237559 2012-06-25 09:41:47Z 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_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, usdt and fasttrap providers. 118 */ 119 dtrace_fasttrap_probe_ptr_t dtrace_fasttrap_probe_ptr; 120 dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr; 121 dtrace_return_probe_ptr_t dtrace_return_probe_ptr; 122 #endif 123 124 extern void trap(struct trapframe *frame); 125 extern void syscall(struct trapframe *frame); 126 void dblfault_handler(struct trapframe *frame); 127 128 static int trap_pfault(struct trapframe *, int); 129 static void trap_fatal(struct trapframe *, vm_offset_t); 130 131 #define MAX_TRAP_MSG 33 132 static char *trap_msg[] = { 133 "", /* 0 unused */ 134 "privileged instruction fault", /* 1 T_PRIVINFLT */ 135 "", /* 2 unused */ 136 "breakpoint instruction fault", /* 3 T_BPTFLT */ 137 "", /* 4 unused */ 138 "", /* 5 unused */ 139 "arithmetic trap", /* 6 T_ARITHTRAP */ 140 "", /* 7 unused */ 141 "", /* 8 unused */ 142 "general protection fault", /* 9 T_PROTFLT */ 143 "trace trap", /* 10 T_TRCTRAP */ 144 "", /* 11 unused */ 145 "page fault", /* 12 T_PAGEFLT */ 146 "", /* 13 unused */ 147 "alignment fault", /* 14 T_ALIGNFLT */ 148 "", /* 15 unused */ 149 "", /* 16 unused */ 150 "", /* 17 unused */ 151 "integer divide fault", /* 18 T_DIVIDE */ 152 "non-maskable interrupt trap", /* 19 T_NMI */ 153 "overflow trap", /* 20 T_OFLOW */ 154 "FPU bounds check fault", /* 21 T_BOUND */ 155 "FPU device not available", /* 22 T_DNA */ 156 "double fault", /* 23 T_DOUBLEFLT */ 157 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 158 "invalid TSS fault", /* 25 T_TSSFLT */ 159 "segment not present fault", /* 26 T_SEGNPFLT */ 160 "stack fault", /* 27 T_STKFLT */ 161 "machine check trap", /* 28 T_MCHK */ 162 "SIMD floating-point exception", /* 29 T_XMMFLT */ 163 "reserved (unknown) fault", /* 30 T_RESERVED */ 164 "", /* 31 unused (reserved) */ 165 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 166 "DTrace fasttrap probe trap", /* 33 T_DTRACE_PROBE */ 167 }; 168 169 #ifdef KDB 170 static int kdb_on_nmi = 1; 171 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 172 &kdb_on_nmi, 0, "Go to KDB on NMI"); 173 TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi); 174 #endif 175 static int panic_on_nmi = 1; 176 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 177 &panic_on_nmi, 0, "Panic on NMI"); 178 TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi); 179 static int prot_fault_translation = 0; 180 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 181 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 182 183 /* 184 * Exception, fault, and trap interface to the FreeBSD kernel. 185 * This common code is called from assembly language IDT gate entry 186 * routines that prepare a suitable stack frame, and restore this 187 * frame after the exception has been processed. 188 */ 189 190 void 191 trap(struct trapframe *frame) 192 { 193 struct thread *td = curthread; 194 struct proc *p = td->td_proc; 195 int i = 0, ucode = 0, code; 196 u_int type; 197 register_t addr = 0; 198 ksiginfo_t ksi; 199 200 PCPU_INC(cnt.v_trap); 201 type = frame->tf_trapno; 202 203 #ifdef SMP 204 /* Handler for NMI IPIs used for stopping CPUs. */ 205 if (type == T_NMI) { 206 if (ipi_nmi_handler() == 0) 207 goto out; 208 } 209 #endif /* SMP */ 210 211 #ifdef KDB 212 if (kdb_active) { 213 kdb_reenter(); 214 goto out; 215 } 216 #endif 217 218 if (type == T_RESERVED) { 219 trap_fatal(frame, 0); 220 goto out; 221 } 222 223 #ifdef HWPMC_HOOKS 224 /* 225 * CPU PMCs interrupt using an NMI. If the PMC module is 226 * active, pass the 'rip' value to the PMC module's interrupt 227 * handler. A return value of '1' from the handler means that 228 * the NMI was handled by it and we can return immediately. 229 */ 230 if (type == T_NMI && pmc_intr && 231 (*pmc_intr)(PCPU_GET(cpuid), frame)) 232 goto out; 233 #endif 234 235 if (type == T_MCHK) { 236 mca_intr(); 237 goto out; 238 } 239 240 #ifdef KDTRACE_HOOKS 241 /* 242 * A trap can occur while DTrace executes a probe. Before 243 * executing the probe, DTrace blocks re-scheduling and sets 244 * a flag in it's per-cpu flags to indicate that it doesn't 245 * want to fault. On returning from the probe, the no-fault 246 * flag is cleared and finally re-scheduling is enabled. 247 * 248 * If the DTrace kernel module has registered a trap handler, 249 * call it and if it returns non-zero, assume that it has 250 * handled the trap and modified the trap frame so that this 251 * function can return normally. 252 */ 253 if (type == T_DTRACE_PROBE || type == T_DTRACE_RET || 254 type == T_BPTFLT) { 255 struct reg regs; 256 257 fill_frame_regs(frame, ®s); 258 if (type == T_DTRACE_PROBE && 259 dtrace_fasttrap_probe_ptr != NULL && 260 dtrace_fasttrap_probe_ptr(®s) == 0) 261 goto out; 262 else if (type == T_BPTFLT && 263 dtrace_pid_probe_ptr != NULL && 264 dtrace_pid_probe_ptr(®s) == 0) 265 goto out; 266 else if (type == T_DTRACE_RET && 267 dtrace_return_probe_ptr != NULL && 268 dtrace_return_probe_ptr(®s) == 0) 269 goto out; 270 } 271 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type)) 272 goto out; 273 #endif 274 275 if ((frame->tf_rflags & PSL_I) == 0) { 276 /* 277 * Buggy application or kernel code has disabled 278 * interrupts and then trapped. Enabling interrupts 279 * now is wrong, but it is better than running with 280 * interrupts disabled until they are accidentally 281 * enabled later. 282 */ 283 if (ISPL(frame->tf_cs) == SEL_UPL) 284 uprintf( 285 "pid %ld (%s): trap %d with interrupts disabled\n", 286 (long)curproc->p_pid, curthread->td_name, type); 287 else if (type != T_NMI && type != T_BPTFLT && 288 type != T_TRCTRAP) { 289 /* 290 * XXX not quite right, since this may be for a 291 * multiple fault in user mode. 292 */ 293 printf("kernel trap %d with interrupts disabled\n", 294 type); 295 296 /* 297 * We shouldn't enable interrupts while holding a 298 * spin lock. 299 */ 300 if (td->td_md.md_spinlock_count == 0) 301 enable_intr(); 302 } 303 } 304 305 code = frame->tf_err; 306 307 if (ISPL(frame->tf_cs) == SEL_UPL) { 308 /* user trap */ 309 310 td->td_pticks = 0; 311 td->td_frame = frame; 312 addr = frame->tf_rip; 313 if (td->td_ucred != p->p_ucred) 314 cred_update_thread(td); 315 316 switch (type) { 317 case T_PRIVINFLT: /* privileged instruction fault */ 318 i = SIGILL; 319 ucode = ILL_PRVOPC; 320 break; 321 322 case T_BPTFLT: /* bpt instruction fault */ 323 case T_TRCTRAP: /* trace trap */ 324 enable_intr(); 325 frame->tf_rflags &= ~PSL_T; 326 i = SIGTRAP; 327 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 328 break; 329 330 case T_ARITHTRAP: /* arithmetic trap */ 331 ucode = fputrap(); 332 if (ucode == -1) 333 goto userout; 334 i = SIGFPE; 335 break; 336 337 case T_PROTFLT: /* general protection fault */ 338 i = SIGBUS; 339 ucode = BUS_OBJERR; 340 break; 341 case T_STKFLT: /* stack fault */ 342 case T_SEGNPFLT: /* segment not present fault */ 343 i = SIGBUS; 344 ucode = BUS_ADRERR; 345 break; 346 case T_TSSFLT: /* invalid TSS fault */ 347 i = SIGBUS; 348 ucode = BUS_OBJERR; 349 break; 350 case T_DOUBLEFLT: /* double fault */ 351 default: 352 i = SIGBUS; 353 ucode = BUS_OBJERR; 354 break; 355 356 case T_PAGEFLT: /* page fault */ 357 addr = frame->tf_addr; 358 i = trap_pfault(frame, TRUE); 359 if (i == -1) 360 goto userout; 361 if (i == 0) 362 goto user; 363 364 if (i == SIGSEGV) 365 ucode = SEGV_MAPERR; 366 else { 367 if (prot_fault_translation == 0) { 368 /* 369 * Autodetect. 370 * This check also covers the images 371 * without the ABI-tag ELF note. 372 */ 373 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 374 && p->p_osrel >= P_OSREL_SIGSEGV) { 375 i = SIGSEGV; 376 ucode = SEGV_ACCERR; 377 } else { 378 i = SIGBUS; 379 ucode = BUS_PAGE_FAULT; 380 } 381 } else if (prot_fault_translation == 1) { 382 /* 383 * Always compat mode. 384 */ 385 i = SIGBUS; 386 ucode = BUS_PAGE_FAULT; 387 } else { 388 /* 389 * Always SIGSEGV mode. 390 */ 391 i = SIGSEGV; 392 ucode = SEGV_ACCERR; 393 } 394 } 395 break; 396 397 case T_DIVIDE: /* integer divide fault */ 398 ucode = FPE_INTDIV; 399 i = SIGFPE; 400 break; 401 402 #ifdef DEV_ISA 403 case T_NMI: 404 /* machine/parity/power fail/"kitchen sink" faults */ 405 if (isa_nmi(code) == 0) { 406 #ifdef KDB 407 /* 408 * NMI can be hooked up to a pushbutton 409 * for debugging. 410 */ 411 if (kdb_on_nmi) { 412 printf ("NMI ... going to debugger\n"); 413 kdb_trap(type, 0, frame); 414 } 415 #endif /* KDB */ 416 goto userout; 417 } else if (panic_on_nmi) 418 panic("NMI indicates hardware failure"); 419 break; 420 #endif /* DEV_ISA */ 421 422 case T_OFLOW: /* integer overflow fault */ 423 ucode = FPE_INTOVF; 424 i = SIGFPE; 425 break; 426 427 case T_BOUND: /* bounds check fault */ 428 ucode = FPE_FLTSUB; 429 i = SIGFPE; 430 break; 431 432 case T_DNA: 433 /* transparent fault (due to context switch "late") */ 434 KASSERT(PCB_USER_FPU(td->td_pcb), 435 ("kernel FPU ctx has leaked")); 436 fpudna(); 437 goto userout; 438 439 case T_FPOPFLT: /* FPU operand fetch fault */ 440 ucode = ILL_COPROC; 441 i = SIGILL; 442 break; 443 444 case T_XMMFLT: /* SIMD floating-point exception */ 445 ucode = 0; /* XXX */ 446 i = SIGFPE; 447 break; 448 } 449 } else { 450 /* kernel trap */ 451 452 KASSERT(cold || td->td_ucred != NULL, 453 ("kernel trap doesn't have ucred")); 454 switch (type) { 455 case T_PAGEFLT: /* page fault */ 456 (void) trap_pfault(frame, FALSE); 457 goto out; 458 459 case T_DNA: 460 KASSERT(!PCB_USER_FPU(td->td_pcb), 461 ("Unregistered use of FPU in kernel")); 462 fpudna(); 463 goto out; 464 465 case T_ARITHTRAP: /* arithmetic trap */ 466 case T_XMMFLT: /* SIMD floating-point exception */ 467 case T_FPOPFLT: /* FPU operand fetch fault */ 468 /* 469 * XXXKIB for now disable any FPU traps in kernel 470 * handler registration seems to be overkill 471 */ 472 trap_fatal(frame, 0); 473 goto out; 474 475 case T_STKFLT: /* stack fault */ 476 break; 477 478 case T_PROTFLT: /* general protection fault */ 479 case T_SEGNPFLT: /* segment not present fault */ 480 if (td->td_intr_nesting_level != 0) 481 break; 482 483 /* 484 * Invalid segment selectors and out of bounds 485 * %rip's and %rsp's can be set up in user mode. 486 * This causes a fault in kernel mode when the 487 * kernel tries to return to user mode. We want 488 * to get this fault so that we can fix the 489 * problem here and not have to check all the 490 * selectors and pointers when the user changes 491 * them. 492 */ 493 if (frame->tf_rip == (long)doreti_iret) { 494 frame->tf_rip = (long)doreti_iret_fault; 495 goto out; 496 } 497 if (frame->tf_rip == (long)ld_ds) { 498 frame->tf_rip = (long)ds_load_fault; 499 goto out; 500 } 501 if (frame->tf_rip == (long)ld_es) { 502 frame->tf_rip = (long)es_load_fault; 503 goto out; 504 } 505 if (frame->tf_rip == (long)ld_fs) { 506 frame->tf_rip = (long)fs_load_fault; 507 goto out; 508 } 509 if (frame->tf_rip == (long)ld_gs) { 510 frame->tf_rip = (long)gs_load_fault; 511 goto out; 512 } 513 if (frame->tf_rip == (long)ld_gsbase) { 514 frame->tf_rip = (long)gsbase_load_fault; 515 goto out; 516 } 517 if (frame->tf_rip == (long)ld_fsbase) { 518 frame->tf_rip = (long)fsbase_load_fault; 519 goto out; 520 } 521 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 522 frame->tf_rip = 523 (long)PCPU_GET(curpcb)->pcb_onfault; 524 goto out; 525 } 526 break; 527 528 case T_TSSFLT: 529 /* 530 * PSL_NT can be set in user mode and isn't cleared 531 * automatically when the kernel is entered. This 532 * causes a TSS fault when the kernel attempts to 533 * `iret' because the TSS link is uninitialized. We 534 * want to get this fault so that we can fix the 535 * problem here and not every time the kernel is 536 * entered. 537 */ 538 if (frame->tf_rflags & PSL_NT) { 539 frame->tf_rflags &= ~PSL_NT; 540 goto out; 541 } 542 break; 543 544 case T_TRCTRAP: /* trace trap */ 545 /* 546 * Ignore debug register trace traps due to 547 * accesses in the user's address space, which 548 * can happen under several conditions such as 549 * if a user sets a watchpoint on a buffer and 550 * then passes that buffer to a system call. 551 * We still want to get TRCTRAPS for addresses 552 * in kernel space because that is useful when 553 * debugging the kernel. 554 */ 555 if (user_dbreg_trap()) { 556 /* 557 * Reset breakpoint bits because the 558 * processor doesn't 559 */ 560 /* XXX check upper bits here */ 561 load_dr6(rdr6() & 0xfffffff0); 562 goto out; 563 } 564 /* 565 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 566 */ 567 case T_BPTFLT: 568 /* 569 * If KDB is enabled, let it handle the debugger trap. 570 * Otherwise, debugger traps "can't happen". 571 */ 572 #ifdef KDB 573 if (kdb_trap(type, 0, frame)) 574 goto out; 575 #endif 576 break; 577 578 #ifdef DEV_ISA 579 case T_NMI: 580 /* machine/parity/power fail/"kitchen sink" faults */ 581 if (isa_nmi(code) == 0) { 582 #ifdef KDB 583 /* 584 * NMI can be hooked up to a pushbutton 585 * for debugging. 586 */ 587 if (kdb_on_nmi) { 588 printf ("NMI ... going to debugger\n"); 589 kdb_trap(type, 0, frame); 590 } 591 #endif /* KDB */ 592 goto out; 593 } else if (panic_on_nmi == 0) 594 goto out; 595 /* FALLTHROUGH */ 596 #endif /* DEV_ISA */ 597 } 598 599 trap_fatal(frame, 0); 600 goto out; 601 } 602 603 /* Translate fault for emulators (e.g. Linux) */ 604 if (*p->p_sysent->sv_transtrap) 605 i = (*p->p_sysent->sv_transtrap)(i, type); 606 607 ksiginfo_init_trap(&ksi); 608 ksi.ksi_signo = i; 609 ksi.ksi_code = ucode; 610 ksi.ksi_trapno = type; 611 ksi.ksi_addr = (void *)addr; 612 trapsignal(td, &ksi); 613 614 user: 615 userret(td, frame); 616 mtx_assert(&Giant, MA_NOTOWNED); 617 KASSERT(PCB_USER_FPU(td->td_pcb), 618 ("Return from trap with kernel FPU ctx leaked")); 619 userout: 620 out: 621 return; 622 } 623 624 static int 625 trap_pfault(frame, usermode) 626 struct trapframe *frame; 627 int usermode; 628 { 629 vm_offset_t va; 630 struct vmspace *vm = NULL; 631 vm_map_t map; 632 int rv = 0; 633 vm_prot_t ftype; 634 struct thread *td = curthread; 635 struct proc *p = td->td_proc; 636 vm_offset_t eva = frame->tf_addr; 637 638 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 639 /* 640 * Due to both processor errata and lazy TLB invalidation when 641 * access restrictions are removed from virtual pages, memory 642 * accesses that are allowed by the physical mapping layer may 643 * nonetheless cause one spurious page fault per virtual page. 644 * When the thread is executing a "no faulting" section that 645 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 646 * every page fault is treated as a spurious page fault, 647 * unless it accesses the same virtual address as the most 648 * recent page fault within the same "no faulting" section. 649 */ 650 if (td->td_md.md_spurflt_addr != eva || 651 (td->td_pflags & TDP_RESETSPUR) != 0) { 652 /* 653 * Do nothing to the TLB. A stale TLB entry is 654 * flushed automatically by a page fault. 655 */ 656 td->td_md.md_spurflt_addr = eva; 657 td->td_pflags &= ~TDP_RESETSPUR; 658 return (0); 659 } 660 } else { 661 /* 662 * If we get a page fault while in a critical section, then 663 * it is most likely a fatal kernel page fault. The kernel 664 * is already going to panic trying to get a sleep lock to 665 * do the VM lookup, so just consider it a fatal trap so the 666 * kernel can print out a useful trap message and even get 667 * to the debugger. 668 * 669 * If we get a page fault while holding a non-sleepable 670 * lock, then it is most likely a fatal kernel page fault. 671 * If WITNESS is enabled, then it's going to whine about 672 * bogus LORs with various VM locks, so just skip to the 673 * fatal trap handling directly. 674 */ 675 if (td->td_critnest != 0 || 676 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 677 "Kernel page fault") != 0) { 678 trap_fatal(frame, eva); 679 return (-1); 680 } 681 } 682 va = trunc_page(eva); 683 if (va >= VM_MIN_KERNEL_ADDRESS) { 684 /* 685 * Don't allow user-mode faults in kernel address space. 686 */ 687 if (usermode) 688 goto nogo; 689 690 map = kernel_map; 691 } else { 692 /* 693 * This is a fault on non-kernel virtual memory. 694 * vm is initialized above to NULL. If curproc is NULL 695 * or curproc->p_vmspace is NULL the fault is fatal. 696 */ 697 if (p != NULL) 698 vm = p->p_vmspace; 699 700 if (vm == NULL) 701 goto nogo; 702 703 map = &vm->vm_map; 704 705 /* 706 * When accessing a usermode address, kernel must be 707 * ready to accept the page fault, and provide a 708 * handling routine. Since accessing the address 709 * without the handler is a bug, do not try to handle 710 * it normally, and panic immediately. 711 */ 712 if (!usermode && (td->td_intr_nesting_level != 0 || 713 PCPU_GET(curpcb)->pcb_onfault == NULL)) { 714 trap_fatal(frame, eva); 715 return (-1); 716 } 717 } 718 719 /* 720 * PGEX_I is defined only if the execute disable bit capability is 721 * supported and enabled. 722 */ 723 if (frame->tf_err & PGEX_W) 724 ftype = VM_PROT_WRITE; 725 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 726 ftype = VM_PROT_EXECUTE; 727 else 728 ftype = VM_PROT_READ; 729 730 if (map != kernel_map) { 731 /* 732 * Keep swapout from messing with us during this 733 * critical time. 734 */ 735 PROC_LOCK(p); 736 ++p->p_lock; 737 PROC_UNLOCK(p); 738 739 /* Fault in the user page: */ 740 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 741 742 PROC_LOCK(p); 743 --p->p_lock; 744 PROC_UNLOCK(p); 745 } else { 746 /* 747 * Don't have to worry about process locking or stacks in the 748 * kernel. 749 */ 750 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 751 } 752 if (rv == KERN_SUCCESS) { 753 #ifdef HWPMC_HOOKS 754 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 755 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 756 if (ftype == VM_PROT_READ) 757 PMC_SOFT_CALL_TF( , , page_fault, read, 758 frame); 759 else 760 PMC_SOFT_CALL_TF( , , page_fault, write, 761 frame); 762 } 763 #endif 764 return (0); 765 } 766 nogo: 767 if (!usermode) { 768 if (td->td_intr_nesting_level == 0 && 769 PCPU_GET(curpcb)->pcb_onfault != NULL) { 770 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 771 return (0); 772 } 773 trap_fatal(frame, eva); 774 return (-1); 775 } 776 777 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 778 } 779 780 static void 781 trap_fatal(frame, eva) 782 struct trapframe *frame; 783 vm_offset_t eva; 784 { 785 int code, ss; 786 u_int type; 787 long esp; 788 struct soft_segment_descriptor softseg; 789 char *msg; 790 791 code = frame->tf_err; 792 type = frame->tf_trapno; 793 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)], 794 &softseg); 795 796 if (type <= MAX_TRAP_MSG) 797 msg = trap_msg[type]; 798 else 799 msg = "UNKNOWN"; 800 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 801 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 802 #ifdef SMP 803 /* two separate prints in case of a trap on an unmapped page */ 804 printf("cpuid = %d; ", PCPU_GET(cpuid)); 805 printf("apic id = %02x\n", PCPU_GET(apic_id)); 806 #endif 807 if (type == T_PAGEFLT) { 808 printf("fault virtual address = 0x%lx\n", eva); 809 printf("fault code = %s %s %s, %s\n", 810 code & PGEX_U ? "user" : "supervisor", 811 code & PGEX_W ? "write" : "read", 812 code & PGEX_I ? "instruction" : "data", 813 code & PGEX_P ? "protection violation" : "page not present"); 814 } 815 printf("instruction pointer = 0x%lx:0x%lx\n", 816 frame->tf_cs & 0xffff, frame->tf_rip); 817 if (ISPL(frame->tf_cs) == SEL_UPL) { 818 ss = frame->tf_ss & 0xffff; 819 esp = frame->tf_rsp; 820 } else { 821 ss = GSEL(GDATA_SEL, SEL_KPL); 822 esp = (long)&frame->tf_rsp; 823 } 824 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 825 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 826 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 827 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 828 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 829 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 830 softseg.ssd_gran); 831 printf("processor eflags = "); 832 if (frame->tf_rflags & PSL_T) 833 printf("trace trap, "); 834 if (frame->tf_rflags & PSL_I) 835 printf("interrupt enabled, "); 836 if (frame->tf_rflags & PSL_NT) 837 printf("nested task, "); 838 if (frame->tf_rflags & PSL_RF) 839 printf("resume, "); 840 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 841 printf("current process = "); 842 if (curproc) { 843 printf("%lu (%s)\n", 844 (u_long)curproc->p_pid, curthread->td_name ? 845 curthread->td_name : ""); 846 } else { 847 printf("Idle\n"); 848 } 849 850 #ifdef KDB 851 if (debugger_on_panic || kdb_active) 852 if (kdb_trap(type, 0, frame)) 853 return; 854 #endif 855 printf("trap number = %d\n", type); 856 if (type <= MAX_TRAP_MSG) 857 panic("%s", trap_msg[type]); 858 else 859 panic("unknown/reserved trap"); 860 } 861 862 /* 863 * Double fault handler. Called when a fault occurs while writing 864 * a frame for a trap/exception onto the stack. This usually occurs 865 * when the stack overflows (such is the case with infinite recursion, 866 * for example). 867 */ 868 void 869 dblfault_handler(struct trapframe *frame) 870 { 871 #ifdef KDTRACE_HOOKS 872 if (dtrace_doubletrap_func != NULL) 873 (*dtrace_doubletrap_func)(); 874 #endif 875 printf("\nFatal double fault\n"); 876 printf("rip = 0x%lx\n", frame->tf_rip); 877 printf("rsp = 0x%lx\n", frame->tf_rsp); 878 printf("rbp = 0x%lx\n", frame->tf_rbp); 879 #ifdef SMP 880 /* two separate prints in case of a trap on an unmapped page */ 881 printf("cpuid = %d; ", PCPU_GET(cpuid)); 882 printf("apic id = %02x\n", PCPU_GET(apic_id)); 883 #endif 884 panic("double fault"); 885 } 886 887 int 888 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 889 { 890 struct proc *p; 891 struct trapframe *frame; 892 register_t *argp; 893 caddr_t params; 894 int reg, regcnt, error; 895 896 p = td->td_proc; 897 frame = td->td_frame; 898 reg = 0; 899 regcnt = 6; 900 901 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 902 sa->code = frame->tf_rax; 903 904 if (sa->code == SYS_syscall || sa->code == SYS___syscall) { 905 sa->code = frame->tf_rdi; 906 reg++; 907 regcnt--; 908 } 909 if (p->p_sysent->sv_mask) 910 sa->code &= p->p_sysent->sv_mask; 911 912 if (sa->code >= p->p_sysent->sv_size) 913 sa->callp = &p->p_sysent->sv_table[0]; 914 else 915 sa->callp = &p->p_sysent->sv_table[sa->code]; 916 917 sa->narg = sa->callp->sy_narg; 918 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]), 919 ("Too many syscall arguments!")); 920 error = 0; 921 argp = &frame->tf_rdi; 922 argp += reg; 923 bcopy(argp, sa->args, sizeof(sa->args[0]) * regcnt); 924 if (sa->narg > regcnt) { 925 KASSERT(params != NULL, ("copyin args with no params!")); 926 error = copyin(params, &sa->args[regcnt], 927 (sa->narg - regcnt) * sizeof(sa->args[0])); 928 } 929 930 if (error == 0) { 931 td->td_retval[0] = 0; 932 td->td_retval[1] = frame->tf_rdx; 933 } 934 935 return (error); 936 } 937 938 #include "../../kern/subr_syscall.c" 939 940 /* 941 * System call handler for native binaries. The trap frame is already 942 * set up by the assembler trampoline and a pointer to it is saved in 943 * td_frame. 944 */ 945 void 946 amd64_syscall(struct thread *td, int traced) 947 { 948 struct syscall_args sa; 949 int error; 950 ksiginfo_t ksi; 951 952 #ifdef DIAGNOSTIC 953 if (ISPL(td->td_frame->tf_cs) != SEL_UPL) { 954 panic("syscall"); 955 /* NOT REACHED */ 956 } 957 #endif 958 error = syscallenter(td, &sa); 959 960 /* 961 * Traced syscall. 962 */ 963 if (__predict_false(traced)) { 964 td->td_frame->tf_rflags &= ~PSL_T; 965 ksiginfo_init_trap(&ksi); 966 ksi.ksi_signo = SIGTRAP; 967 ksi.ksi_code = TRAP_TRACE; 968 ksi.ksi_addr = (void *)td->td_frame->tf_rip; 969 trapsignal(td, &ksi); 970 } 971 972 KASSERT(PCB_USER_FPU(td->td_pcb), 973 ("System call %s returing with kernel FPU ctx leaked", 974 syscallname(td->td_proc, sa.code))); 975 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td), 976 ("System call %s returning with mangled pcb_save", 977 syscallname(td->td_proc, sa.code))); 978 979 syscallret(td, error, &sa); 980 981 /* 982 * If the user-supplied value of %rip is not a canonical 983 * address, then some CPUs will trigger a ring 0 #GP during 984 * the sysret instruction. However, the fault handler would 985 * execute in ring 0 with the user's %gs and %rsp which would 986 * not be safe. Instead, use the full return path which 987 * catches the problem safely. 988 */ 989 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) 990 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 991 }
Cache object: b8cccc05a5412b6d165344a276cd4c80
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