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 53 #include <sys/param.h> 54 #include <sys/bus.h> 55 #include <sys/systm.h> 56 #include <sys/proc.h> 57 #include <sys/pioctl.h> 58 #include <sys/ptrace.h> 59 #include <sys/kdb.h> 60 #include <sys/kernel.h> 61 #include <sys/ktr.h> 62 #include <sys/lock.h> 63 #include <sys/mutex.h> 64 #include <sys/resourcevar.h> 65 #include <sys/signalvar.h> 66 #include <sys/syscall.h> 67 #include <sys/sysctl.h> 68 #include <sys/sysent.h> 69 #include <sys/uio.h> 70 #include <sys/vmmeter.h> 71 #ifdef HWPMC_HOOKS 72 #include <sys/pmckern.h> 73 PMC_SOFT_DEFINE( , , page_fault, all); 74 PMC_SOFT_DEFINE( , , page_fault, read); 75 PMC_SOFT_DEFINE( , , page_fault, write); 76 #endif 77 78 #include <vm/vm.h> 79 #include <vm/vm_param.h> 80 #include <vm/pmap.h> 81 #include <vm/vm_kern.h> 82 #include <vm/vm_map.h> 83 #include <vm/vm_page.h> 84 #include <vm/vm_extern.h> 85 86 #include <machine/cpu.h> 87 #include <machine/intr_machdep.h> 88 #include <x86/mca.h> 89 #include <machine/md_var.h> 90 #include <machine/pcb.h> 91 #ifdef SMP 92 #include <machine/smp.h> 93 #endif 94 #include <machine/tss.h> 95 96 #ifdef KDTRACE_HOOKS 97 #include <sys/dtrace_bsd.h> 98 #endif 99 100 extern void __noinline trap(struct trapframe *frame); 101 extern void trap_check(struct trapframe *frame); 102 extern void syscall(struct trapframe *frame); 103 void dblfault_handler(struct trapframe *frame); 104 105 static int trap_pfault(struct trapframe *, int); 106 static void trap_fatal(struct trapframe *, vm_offset_t); 107 108 #define MAX_TRAP_MSG 32 109 static char *trap_msg[] = { 110 "", /* 0 unused */ 111 "privileged instruction fault", /* 1 T_PRIVINFLT */ 112 "", /* 2 unused */ 113 "breakpoint instruction fault", /* 3 T_BPTFLT */ 114 "", /* 4 unused */ 115 "", /* 5 unused */ 116 "arithmetic trap", /* 6 T_ARITHTRAP */ 117 "", /* 7 unused */ 118 "", /* 8 unused */ 119 "general protection fault", /* 9 T_PROTFLT */ 120 "trace trap", /* 10 T_TRCTRAP */ 121 "", /* 11 unused */ 122 "page fault", /* 12 T_PAGEFLT */ 123 "", /* 13 unused */ 124 "alignment fault", /* 14 T_ALIGNFLT */ 125 "", /* 15 unused */ 126 "", /* 16 unused */ 127 "", /* 17 unused */ 128 "integer divide fault", /* 18 T_DIVIDE */ 129 "non-maskable interrupt trap", /* 19 T_NMI */ 130 "overflow trap", /* 20 T_OFLOW */ 131 "FPU bounds check fault", /* 21 T_BOUND */ 132 "FPU device not available", /* 22 T_DNA */ 133 "double fault", /* 23 T_DOUBLEFLT */ 134 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 135 "invalid TSS fault", /* 25 T_TSSFLT */ 136 "segment not present fault", /* 26 T_SEGNPFLT */ 137 "stack fault", /* 27 T_STKFLT */ 138 "machine check trap", /* 28 T_MCHK */ 139 "SIMD floating-point exception", /* 29 T_XMMFLT */ 140 "reserved (unknown) fault", /* 30 T_RESERVED */ 141 "", /* 31 unused (reserved) */ 142 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 143 }; 144 145 #ifdef KDB 146 static int kdb_on_nmi = 1; 147 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RWTUN, 148 &kdb_on_nmi, 0, "Go to KDB on NMI"); 149 #endif 150 static int panic_on_nmi = 1; 151 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RWTUN, 152 &panic_on_nmi, 0, "Panic on NMI"); 153 static int prot_fault_translation; 154 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RWTUN, 155 &prot_fault_translation, 0, 156 "Select signal to deliver on protection fault"); 157 static int uprintf_signal; 158 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RWTUN, 159 &uprintf_signal, 0, 160 "Print debugging information on trap signal to ctty"); 161 162 /* 163 * Exception, fault, and trap interface to the FreeBSD kernel. 164 * This common code is called from assembly language IDT gate entry 165 * routines that prepare a suitable stack frame, and restore this 166 * frame after the exception has been processed. 167 */ 168 169 void 170 trap(struct trapframe *frame) 171 { 172 #ifdef KDTRACE_HOOKS 173 struct reg regs; 174 #endif 175 struct thread *td = curthread; 176 struct proc *p = td->td_proc; 177 int i = 0, ucode = 0, code; 178 u_int type; 179 register_t addr = 0; 180 ksiginfo_t ksi; 181 182 PCPU_INC(cnt.v_trap); 183 type = frame->tf_trapno; 184 185 #ifdef SMP 186 /* Handler for NMI IPIs used for stopping CPUs. */ 187 if (type == T_NMI) { 188 if (ipi_nmi_handler() == 0) 189 goto out; 190 } 191 #endif /* SMP */ 192 193 #ifdef KDB 194 if (kdb_active) { 195 kdb_reenter(); 196 goto out; 197 } 198 #endif 199 200 if (type == T_RESERVED) { 201 trap_fatal(frame, 0); 202 goto out; 203 } 204 205 #ifdef HWPMC_HOOKS 206 /* 207 * CPU PMCs interrupt using an NMI. If the PMC module is 208 * active, pass the 'rip' value to the PMC module's interrupt 209 * handler. A return value of '1' from the handler means that 210 * the NMI was handled by it and we can return immediately. 211 */ 212 if (type == T_NMI && pmc_intr && 213 (*pmc_intr)(PCPU_GET(cpuid), frame)) 214 goto out; 215 #endif 216 217 if (type == T_MCHK) { 218 mca_intr(); 219 goto out; 220 } 221 222 if ((frame->tf_rflags & PSL_I) == 0) { 223 /* 224 * Buggy application or kernel code has disabled 225 * interrupts and then trapped. Enabling interrupts 226 * now is wrong, but it is better than running with 227 * interrupts disabled until they are accidentally 228 * enabled later. 229 */ 230 if (ISPL(frame->tf_cs) == SEL_UPL) 231 uprintf( 232 "pid %ld (%s): trap %d with interrupts disabled\n", 233 (long)curproc->p_pid, curthread->td_name, type); 234 else if (type != T_NMI && type != T_BPTFLT && 235 type != T_TRCTRAP) { 236 /* 237 * XXX not quite right, since this may be for a 238 * multiple fault in user mode. 239 */ 240 printf("kernel trap %d with interrupts disabled\n", 241 type); 242 243 /* 244 * We shouldn't enable interrupts while holding a 245 * spin lock. 246 */ 247 if (td->td_md.md_spinlock_count == 0) 248 enable_intr(); 249 } 250 } 251 252 code = frame->tf_err; 253 254 if (ISPL(frame->tf_cs) == SEL_UPL) { 255 /* user trap */ 256 257 td->td_pticks = 0; 258 td->td_frame = frame; 259 addr = frame->tf_rip; 260 if (td->td_ucred != p->p_ucred) 261 cred_update_thread(td); 262 263 switch (type) { 264 case T_PRIVINFLT: /* privileged instruction fault */ 265 i = SIGILL; 266 ucode = ILL_PRVOPC; 267 break; 268 269 case T_BPTFLT: /* bpt instruction fault */ 270 case T_TRCTRAP: /* trace trap */ 271 enable_intr(); 272 #ifdef KDTRACE_HOOKS 273 if (type == T_BPTFLT) { 274 fill_frame_regs(frame, ®s); 275 if (dtrace_pid_probe_ptr != NULL && 276 dtrace_pid_probe_ptr(®s) == 0) 277 goto out; 278 } 279 #endif 280 frame->tf_rflags &= ~PSL_T; 281 i = SIGTRAP; 282 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 283 break; 284 285 case T_ARITHTRAP: /* arithmetic trap */ 286 ucode = fputrap_x87(); 287 if (ucode == -1) 288 goto userout; 289 i = SIGFPE; 290 break; 291 292 case T_PROTFLT: /* general protection fault */ 293 i = SIGBUS; 294 ucode = BUS_OBJERR; 295 break; 296 case T_STKFLT: /* stack fault */ 297 case T_SEGNPFLT: /* segment not present fault */ 298 i = SIGBUS; 299 ucode = BUS_ADRERR; 300 break; 301 case T_TSSFLT: /* invalid TSS fault */ 302 i = SIGBUS; 303 ucode = BUS_OBJERR; 304 break; 305 case T_ALIGNFLT: 306 i = SIGBUS; 307 ucode = BUS_ADRALN; 308 break; 309 case T_DOUBLEFLT: /* double fault */ 310 default: 311 i = SIGBUS; 312 ucode = BUS_OBJERR; 313 break; 314 315 case T_PAGEFLT: /* page fault */ 316 addr = frame->tf_addr; 317 i = trap_pfault(frame, TRUE); 318 if (i == -1) 319 goto userout; 320 if (i == 0) 321 goto user; 322 323 if (i == SIGSEGV) 324 ucode = SEGV_MAPERR; 325 else { 326 if (prot_fault_translation == 0) { 327 /* 328 * Autodetect. 329 * This check also covers the images 330 * without the ABI-tag ELF note. 331 */ 332 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 333 && p->p_osrel >= P_OSREL_SIGSEGV) { 334 i = SIGSEGV; 335 ucode = SEGV_ACCERR; 336 } else { 337 i = SIGBUS; 338 ucode = BUS_PAGE_FAULT; 339 } 340 } else if (prot_fault_translation == 1) { 341 /* 342 * Always compat mode. 343 */ 344 i = SIGBUS; 345 ucode = BUS_PAGE_FAULT; 346 } else { 347 /* 348 * Always SIGSEGV mode. 349 */ 350 i = SIGSEGV; 351 ucode = SEGV_ACCERR; 352 } 353 } 354 break; 355 356 case T_DIVIDE: /* integer divide fault */ 357 ucode = FPE_INTDIV; 358 i = SIGFPE; 359 break; 360 361 #ifdef DEV_ISA 362 case T_NMI: 363 /* machine/parity/power fail/"kitchen sink" faults */ 364 if (isa_nmi(code) == 0) { 365 #ifdef KDB 366 /* 367 * NMI can be hooked up to a pushbutton 368 * for debugging. 369 */ 370 if (kdb_on_nmi) { 371 printf ("NMI ... going to debugger\n"); 372 kdb_trap(type, 0, frame); 373 } 374 #endif /* KDB */ 375 goto userout; 376 } else if (panic_on_nmi) 377 panic("NMI indicates hardware failure"); 378 break; 379 #endif /* DEV_ISA */ 380 381 case T_OFLOW: /* integer overflow fault */ 382 ucode = FPE_INTOVF; 383 i = SIGFPE; 384 break; 385 386 case T_BOUND: /* bounds check fault */ 387 ucode = FPE_FLTSUB; 388 i = SIGFPE; 389 break; 390 391 case T_DNA: 392 /* transparent fault (due to context switch "late") */ 393 KASSERT(PCB_USER_FPU(td->td_pcb), 394 ("kernel FPU ctx has leaked")); 395 fpudna(); 396 goto userout; 397 398 case T_FPOPFLT: /* FPU operand fetch fault */ 399 ucode = ILL_COPROC; 400 i = SIGILL; 401 break; 402 403 case T_XMMFLT: /* SIMD floating-point exception */ 404 ucode = fputrap_sse(); 405 if (ucode == -1) 406 goto userout; 407 i = SIGFPE; 408 break; 409 #ifdef KDTRACE_HOOKS 410 case T_DTRACE_RET: 411 enable_intr(); 412 fill_frame_regs(frame, ®s); 413 if (dtrace_return_probe_ptr != NULL && 414 dtrace_return_probe_ptr(®s) == 0) 415 goto out; 416 break; 417 #endif 418 } 419 } else { 420 /* kernel trap */ 421 422 KASSERT(cold || td->td_ucred != NULL, 423 ("kernel trap doesn't have ucred")); 424 switch (type) { 425 case T_PAGEFLT: /* page fault */ 426 (void) trap_pfault(frame, FALSE); 427 goto out; 428 429 case T_DNA: 430 KASSERT(!PCB_USER_FPU(td->td_pcb), 431 ("Unregistered use of FPU in kernel")); 432 fpudna(); 433 goto out; 434 435 case T_ARITHTRAP: /* arithmetic trap */ 436 case T_XMMFLT: /* SIMD floating-point exception */ 437 case T_FPOPFLT: /* FPU operand fetch fault */ 438 /* 439 * For now, supporting kernel handler 440 * registration for FPU traps is overkill. 441 */ 442 trap_fatal(frame, 0); 443 goto out; 444 445 case T_STKFLT: /* stack fault */ 446 case T_PROTFLT: /* general protection fault */ 447 case T_SEGNPFLT: /* segment not present fault */ 448 if (td->td_intr_nesting_level != 0) 449 break; 450 451 /* 452 * Invalid segment selectors and out of bounds 453 * %rip's and %rsp's can be set up in user mode. 454 * This causes a fault in kernel mode when the 455 * kernel tries to return to user mode. We want 456 * to get this fault so that we can fix the 457 * problem here and not have to check all the 458 * selectors and pointers when the user changes 459 * them. 460 */ 461 if (frame->tf_rip == (long)doreti_iret) { 462 frame->tf_rip = (long)doreti_iret_fault; 463 goto out; 464 } 465 if (frame->tf_rip == (long)ld_ds) { 466 frame->tf_rip = (long)ds_load_fault; 467 goto out; 468 } 469 if (frame->tf_rip == (long)ld_es) { 470 frame->tf_rip = (long)es_load_fault; 471 goto out; 472 } 473 if (frame->tf_rip == (long)ld_fs) { 474 frame->tf_rip = (long)fs_load_fault; 475 goto out; 476 } 477 if (frame->tf_rip == (long)ld_gs) { 478 frame->tf_rip = (long)gs_load_fault; 479 goto out; 480 } 481 if (frame->tf_rip == (long)ld_gsbase) { 482 frame->tf_rip = (long)gsbase_load_fault; 483 goto out; 484 } 485 if (frame->tf_rip == (long)ld_fsbase) { 486 frame->tf_rip = (long)fsbase_load_fault; 487 goto out; 488 } 489 if (curpcb->pcb_onfault != NULL) { 490 frame->tf_rip = (long)curpcb->pcb_onfault; 491 goto out; 492 } 493 break; 494 495 case T_TSSFLT: 496 /* 497 * PSL_NT can be set in user mode and isn't cleared 498 * automatically when the kernel is entered. This 499 * causes a TSS fault when the kernel attempts to 500 * `iret' because the TSS link is uninitialized. We 501 * want to get this fault so that we can fix the 502 * problem here and not every time the kernel is 503 * entered. 504 */ 505 if (frame->tf_rflags & PSL_NT) { 506 frame->tf_rflags &= ~PSL_NT; 507 goto out; 508 } 509 break; 510 511 case T_TRCTRAP: /* trace trap */ 512 /* 513 * Ignore debug register trace traps due to 514 * accesses in the user's address space, which 515 * can happen under several conditions such as 516 * if a user sets a watchpoint on a buffer and 517 * then passes that buffer to a system call. 518 * We still want to get TRCTRAPS for addresses 519 * in kernel space because that is useful when 520 * debugging the kernel. 521 */ 522 if (user_dbreg_trap()) { 523 /* 524 * Reset breakpoint bits because the 525 * processor doesn't 526 */ 527 /* XXX check upper bits here */ 528 load_dr6(rdr6() & 0xfffffff0); 529 goto out; 530 } 531 /* 532 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 533 */ 534 case T_BPTFLT: 535 /* 536 * If KDB is enabled, let it handle the debugger trap. 537 * Otherwise, debugger traps "can't happen". 538 */ 539 #ifdef KDB 540 if (kdb_trap(type, 0, frame)) 541 goto out; 542 #endif 543 break; 544 545 #ifdef DEV_ISA 546 case T_NMI: 547 /* machine/parity/power fail/"kitchen sink" faults */ 548 if (isa_nmi(code) == 0) { 549 #ifdef KDB 550 /* 551 * NMI can be hooked up to a pushbutton 552 * for debugging. 553 */ 554 if (kdb_on_nmi) { 555 printf ("NMI ... going to debugger\n"); 556 kdb_trap(type, 0, frame); 557 } 558 #endif /* KDB */ 559 goto out; 560 } else if (panic_on_nmi == 0) 561 goto out; 562 /* FALLTHROUGH */ 563 #endif /* DEV_ISA */ 564 } 565 566 trap_fatal(frame, 0); 567 goto out; 568 } 569 570 /* Translate fault for emulators (e.g. Linux) */ 571 if (*p->p_sysent->sv_transtrap) 572 i = (*p->p_sysent->sv_transtrap)(i, type); 573 574 ksiginfo_init_trap(&ksi); 575 ksi.ksi_signo = i; 576 ksi.ksi_code = ucode; 577 ksi.ksi_trapno = type; 578 ksi.ksi_addr = (void *)addr; 579 if (uprintf_signal) { 580 uprintf("pid %d comm %s: signal %d err %lx code %d type %d " 581 "addr 0x%lx rsp 0x%lx rip 0x%lx " 582 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n", 583 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr, 584 frame->tf_rsp, frame->tf_rip, 585 fubyte((void *)(frame->tf_rip + 0)), 586 fubyte((void *)(frame->tf_rip + 1)), 587 fubyte((void *)(frame->tf_rip + 2)), 588 fubyte((void *)(frame->tf_rip + 3)), 589 fubyte((void *)(frame->tf_rip + 4)), 590 fubyte((void *)(frame->tf_rip + 5)), 591 fubyte((void *)(frame->tf_rip + 6)), 592 fubyte((void *)(frame->tf_rip + 7))); 593 } 594 KASSERT((read_rflags() & PSL_I) != 0, ("interrupts disabled")); 595 trapsignal(td, &ksi); 596 597 user: 598 userret(td, frame); 599 KASSERT(PCB_USER_FPU(td->td_pcb), 600 ("Return from trap with kernel FPU ctx leaked")); 601 userout: 602 out: 603 return; 604 } 605 606 /* 607 * Ensure that we ignore any DTrace-induced faults. This function cannot 608 * be instrumented, so it cannot generate such faults itself. 609 */ 610 void 611 trap_check(struct trapframe *frame) 612 { 613 614 #ifdef KDTRACE_HOOKS 615 if (dtrace_trap_func != NULL && 616 (*dtrace_trap_func)(frame, frame->tf_trapno) != 0) 617 return; 618 #endif 619 trap(frame); 620 } 621 622 static int 623 trap_pfault(frame, usermode) 624 struct trapframe *frame; 625 int usermode; 626 { 627 vm_offset_t va; 628 struct vmspace *vm; 629 vm_map_t map; 630 int rv = 0; 631 vm_prot_t ftype; 632 struct thread *td = curthread; 633 struct proc *p = td->td_proc; 634 vm_offset_t eva = frame->tf_addr; 635 636 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) { 637 /* 638 * Due to both processor errata and lazy TLB invalidation when 639 * access restrictions are removed from virtual pages, memory 640 * accesses that are allowed by the physical mapping layer may 641 * nonetheless cause one spurious page fault per virtual page. 642 * When the thread is executing a "no faulting" section that 643 * is bracketed by vm_fault_{disable,enable}_pagefaults(), 644 * every page fault is treated as a spurious page fault, 645 * unless it accesses the same virtual address as the most 646 * recent page fault within the same "no faulting" section. 647 */ 648 if (td->td_md.md_spurflt_addr != eva || 649 (td->td_pflags & TDP_RESETSPUR) != 0) { 650 /* 651 * Do nothing to the TLB. A stale TLB entry is 652 * flushed automatically by a page fault. 653 */ 654 td->td_md.md_spurflt_addr = eva; 655 td->td_pflags &= ~TDP_RESETSPUR; 656 return (0); 657 } 658 } else { 659 /* 660 * If we get a page fault while in a critical section, then 661 * it is most likely a fatal kernel page fault. The kernel 662 * is already going to panic trying to get a sleep lock to 663 * do the VM lookup, so just consider it a fatal trap so the 664 * kernel can print out a useful trap message and even get 665 * to the debugger. 666 * 667 * If we get a page fault while holding a non-sleepable 668 * lock, then it is most likely a fatal kernel page fault. 669 * If WITNESS is enabled, then it's going to whine about 670 * bogus LORs with various VM locks, so just skip to the 671 * fatal trap handling directly. 672 */ 673 if (td->td_critnest != 0 || 674 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 675 "Kernel page fault") != 0) { 676 trap_fatal(frame, eva); 677 return (-1); 678 } 679 } 680 va = trunc_page(eva); 681 if (va >= VM_MIN_KERNEL_ADDRESS) { 682 /* 683 * Don't allow user-mode faults in kernel address space. 684 */ 685 if (usermode) 686 goto nogo; 687 688 map = kernel_map; 689 } else { 690 /* 691 * This is a fault on non-kernel virtual memory. If either 692 * p or p->p_vmspace is NULL, then the fault is fatal. 693 */ 694 if (p == NULL || (vm = p->p_vmspace) == NULL) 695 goto nogo; 696 697 map = &vm->vm_map; 698 699 /* 700 * When accessing a usermode address, kernel must be 701 * ready to accept the page fault, and provide a 702 * handling routine. Since accessing the address 703 * without the handler is a bug, do not try to handle 704 * it normally, and panic immediately. 705 */ 706 if (!usermode && (td->td_intr_nesting_level != 0 || 707 curpcb->pcb_onfault == NULL)) { 708 trap_fatal(frame, eva); 709 return (-1); 710 } 711 } 712 713 /* 714 * If the trap was caused by errant bits in the PTE then panic. 715 */ 716 if (frame->tf_err & PGEX_RSV) { 717 trap_fatal(frame, eva); 718 return (-1); 719 } 720 721 /* 722 * PGEX_I is defined only if the execute disable bit capability is 723 * supported and enabled. 724 */ 725 if (frame->tf_err & PGEX_W) 726 ftype = VM_PROT_WRITE; 727 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 728 ftype = VM_PROT_EXECUTE; 729 else 730 ftype = VM_PROT_READ; 731 732 if (map != kernel_map) { 733 /* 734 * Keep swapout from messing with us during this 735 * critical time. 736 */ 737 PROC_LOCK(p); 738 ++p->p_lock; 739 PROC_UNLOCK(p); 740 741 /* Fault in the user page: */ 742 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 743 744 PROC_LOCK(p); 745 --p->p_lock; 746 PROC_UNLOCK(p); 747 } else { 748 /* 749 * Don't have to worry about process locking or stacks in the 750 * kernel. 751 */ 752 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 753 } 754 if (rv == KERN_SUCCESS) { 755 #ifdef HWPMC_HOOKS 756 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) { 757 PMC_SOFT_CALL_TF( , , page_fault, all, frame); 758 if (ftype == VM_PROT_READ) 759 PMC_SOFT_CALL_TF( , , page_fault, read, 760 frame); 761 else 762 PMC_SOFT_CALL_TF( , , page_fault, write, 763 frame); 764 } 765 #endif 766 return (0); 767 } 768 nogo: 769 if (!usermode) { 770 if (td->td_intr_nesting_level == 0 && 771 curpcb->pcb_onfault != NULL) { 772 frame->tf_rip = (long)curpcb->pcb_onfault; 773 return (0); 774 } 775 trap_fatal(frame, eva); 776 return (-1); 777 } 778 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 779 } 780 781 static void 782 trap_fatal(frame, eva) 783 struct trapframe *frame; 784 vm_offset_t eva; 785 { 786 int code, ss; 787 u_int type; 788 long esp; 789 struct soft_segment_descriptor softseg; 790 char *msg; 791 792 code = frame->tf_err; 793 type = frame->tf_trapno; 794 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)], 795 &softseg); 796 797 if (type <= MAX_TRAP_MSG) 798 msg = trap_msg[type]; 799 else 800 msg = "UNKNOWN"; 801 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 802 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 803 #ifdef SMP 804 /* two separate prints in case of a trap on an unmapped page */ 805 printf("cpuid = %d; ", PCPU_GET(cpuid)); 806 printf("apic id = %02x\n", PCPU_GET(apic_id)); 807 #endif 808 if (type == T_PAGEFLT) { 809 printf("fault virtual address = 0x%lx\n", eva); 810 printf("fault code = %s %s %s%s, %s\n", 811 code & PGEX_U ? "user" : "supervisor", 812 code & PGEX_W ? "write" : "read", 813 code & PGEX_I ? "instruction" : "data", 814 code & PGEX_RSV ? " rsv" : "", 815 code & PGEX_P ? "protection violation" : "page not present"); 816 } 817 printf("instruction pointer = 0x%lx:0x%lx\n", 818 frame->tf_cs & 0xffff, frame->tf_rip); 819 if (ISPL(frame->tf_cs) == SEL_UPL) { 820 ss = frame->tf_ss & 0xffff; 821 esp = frame->tf_rsp; 822 } else { 823 ss = GSEL(GDATA_SEL, SEL_KPL); 824 esp = (long)&frame->tf_rsp; 825 } 826 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 827 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 828 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 829 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 830 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 831 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 832 softseg.ssd_gran); 833 printf("processor eflags = "); 834 if (frame->tf_rflags & PSL_T) 835 printf("trace trap, "); 836 if (frame->tf_rflags & PSL_I) 837 printf("interrupt enabled, "); 838 if (frame->tf_rflags & PSL_NT) 839 printf("nested task, "); 840 if (frame->tf_rflags & PSL_RF) 841 printf("resume, "); 842 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 843 printf("current process = "); 844 if (curproc) { 845 printf("%lu (%s)\n", 846 (u_long)curproc->p_pid, curthread->td_name ? 847 curthread->td_name : ""); 848 } else { 849 printf("Idle\n"); 850 } 851 852 #ifdef KDB 853 if (debugger_on_panic || kdb_active) 854 if (kdb_trap(type, 0, frame)) 855 return; 856 #endif 857 printf("trap number = %d\n", type); 858 if (type <= MAX_TRAP_MSG) 859 panic("%s", trap_msg[type]); 860 else 861 panic("unknown/reserved trap"); 862 } 863 864 /* 865 * Double fault handler. Called when a fault occurs while writing 866 * a frame for a trap/exception onto the stack. This usually occurs 867 * when the stack overflows (such is the case with infinite recursion, 868 * for example). 869 */ 870 void 871 dblfault_handler(struct trapframe *frame) 872 { 873 #ifdef KDTRACE_HOOKS 874 if (dtrace_doubletrap_func != NULL) 875 (*dtrace_doubletrap_func)(); 876 #endif 877 printf("\nFatal double fault\n"); 878 printf("rip = 0x%lx\n", frame->tf_rip); 879 printf("rsp = 0x%lx\n", frame->tf_rsp); 880 printf("rbp = 0x%lx\n", frame->tf_rbp); 881 #ifdef SMP 882 /* two separate prints in case of a trap on an unmapped page */ 883 printf("cpuid = %d; ", PCPU_GET(cpuid)); 884 printf("apic id = %02x\n", PCPU_GET(apic_id)); 885 #endif 886 panic("double fault"); 887 } 888 889 int 890 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 891 { 892 struct proc *p; 893 struct trapframe *frame; 894 register_t *argp; 895 caddr_t params; 896 int reg, regcnt, error; 897 898 p = td->td_proc; 899 frame = td->td_frame; 900 reg = 0; 901 regcnt = 6; 902 903 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 904 sa->code = frame->tf_rax; 905 906 if (sa->code == SYS_syscall || sa->code == SYS___syscall) { 907 sa->code = frame->tf_rdi; 908 reg++; 909 regcnt--; 910 } 911 if (p->p_sysent->sv_mask) 912 sa->code &= p->p_sysent->sv_mask; 913 914 if (sa->code >= p->p_sysent->sv_size) 915 sa->callp = &p->p_sysent->sv_table[0]; 916 else 917 sa->callp = &p->p_sysent->sv_table[sa->code]; 918 919 sa->narg = sa->callp->sy_narg; 920 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]), 921 ("Too many syscall arguments!")); 922 error = 0; 923 argp = &frame->tf_rdi; 924 argp += reg; 925 bcopy(argp, sa->args, sizeof(sa->args[0]) * regcnt); 926 if (sa->narg > regcnt) { 927 KASSERT(params != NULL, ("copyin args with no params!")); 928 error = copyin(params, &sa->args[regcnt], 929 (sa->narg - regcnt) * sizeof(sa->args[0])); 930 } 931 932 if (error == 0) { 933 td->td_retval[0] = 0; 934 td->td_retval[1] = frame->tf_rdx; 935 } 936 937 return (error); 938 } 939 940 #include "../../kern/subr_syscall.c" 941 942 /* 943 * System call handler for native binaries. The trap frame is already 944 * set up by the assembler trampoline and a pointer to it is saved in 945 * td_frame. 946 */ 947 void 948 amd64_syscall(struct thread *td, int traced) 949 { 950 struct syscall_args sa; 951 int error; 952 ksiginfo_t ksi; 953 954 #ifdef DIAGNOSTIC 955 if (ISPL(td->td_frame->tf_cs) != SEL_UPL) { 956 panic("syscall"); 957 /* NOT REACHED */ 958 } 959 #endif 960 error = syscallenter(td, &sa); 961 962 /* 963 * Traced syscall. 964 */ 965 if (__predict_false(traced)) { 966 td->td_frame->tf_rflags &= ~PSL_T; 967 ksiginfo_init_trap(&ksi); 968 ksi.ksi_signo = SIGTRAP; 969 ksi.ksi_code = TRAP_TRACE; 970 ksi.ksi_addr = (void *)td->td_frame->tf_rip; 971 trapsignal(td, &ksi); 972 } 973 974 KASSERT(PCB_USER_FPU(td->td_pcb), 975 ("System call %s returing with kernel FPU ctx leaked", 976 syscallname(td->td_proc, sa.code))); 977 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td), 978 ("System call %s returning with mangled pcb_save", 979 syscallname(td->td_proc, sa.code))); 980 981 syscallret(td, error, &sa); 982 983 /* 984 * If the user-supplied value of %rip is not a canonical 985 * address, then some CPUs will trigger a ring 0 #GP during 986 * the sysret instruction. However, the fault handler would 987 * execute in ring 0 with the user's %gs and %rsp which would 988 * not be safe. Instead, use the full return path which 989 * catches the problem safely. 990 */ 991 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) 992 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 993 } 994