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: releng/8.1/sys/amd64/amd64/trap.c 237241 2012-06-18 20:48:21Z simon $"); 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 #include "opt_ktrace.h" 54 55 #include <sys/param.h> 56 #include <sys/bus.h> 57 #include <sys/systm.h> 58 #include <sys/proc.h> 59 #include <sys/pioctl.h> 60 #include <sys/ptrace.h> 61 #include <sys/kdb.h> 62 #include <sys/kernel.h> 63 #include <sys/ktr.h> 64 #include <sys/lock.h> 65 #include <sys/mutex.h> 66 #include <sys/resourcevar.h> 67 #include <sys/signalvar.h> 68 #include <sys/syscall.h> 69 #include <sys/sysctl.h> 70 #include <sys/sysent.h> 71 #include <sys/uio.h> 72 #include <sys/vmmeter.h> 73 #ifdef KTRACE 74 #include <sys/ktrace.h> 75 #endif 76 #ifdef HWPMC_HOOKS 77 #include <sys/pmckern.h> 78 #endif 79 #include <security/audit/audit.h> 80 81 #include <vm/vm.h> 82 #include <vm/vm_param.h> 83 #include <vm/pmap.h> 84 #include <vm/vm_kern.h> 85 #include <vm/vm_map.h> 86 #include <vm/vm_page.h> 87 #include <vm/vm_extern.h> 88 89 #include <machine/cpu.h> 90 #include <machine/intr_machdep.h> 91 #include <machine/mca.h> 92 #include <machine/md_var.h> 93 #include <machine/pcb.h> 94 #ifdef SMP 95 #include <machine/smp.h> 96 #endif 97 #include <machine/tss.h> 98 99 #ifdef KDTRACE_HOOKS 100 #include <sys/dtrace_bsd.h> 101 102 /* 103 * This is a hook which is initialised by the dtrace module 104 * to handle traps which might occur during DTrace probe 105 * execution. 106 */ 107 dtrace_trap_func_t dtrace_trap_func; 108 109 dtrace_doubletrap_func_t dtrace_doubletrap_func; 110 111 /* 112 * This is a hook which is initialised by the systrace module 113 * when it is loaded. This keeps the DTrace syscall provider 114 * implementation opaque. 115 */ 116 systrace_probe_func_t systrace_probe_func; 117 #endif 118 119 extern void trap(struct trapframe *frame); 120 extern void syscall(struct trapframe *frame); 121 void dblfault_handler(struct trapframe *frame); 122 123 static int trap_pfault(struct trapframe *, int); 124 static void trap_fatal(struct trapframe *, vm_offset_t); 125 126 #define MAX_TRAP_MSG 30 127 static char *trap_msg[] = { 128 "", /* 0 unused */ 129 "privileged instruction fault", /* 1 T_PRIVINFLT */ 130 "", /* 2 unused */ 131 "breakpoint instruction fault", /* 3 T_BPTFLT */ 132 "", /* 4 unused */ 133 "", /* 5 unused */ 134 "arithmetic trap", /* 6 T_ARITHTRAP */ 135 "", /* 7 unused */ 136 "", /* 8 unused */ 137 "general protection fault", /* 9 T_PROTFLT */ 138 "trace trap", /* 10 T_TRCTRAP */ 139 "", /* 11 unused */ 140 "page fault", /* 12 T_PAGEFLT */ 141 "", /* 13 unused */ 142 "alignment fault", /* 14 T_ALIGNFLT */ 143 "", /* 15 unused */ 144 "", /* 16 unused */ 145 "", /* 17 unused */ 146 "integer divide fault", /* 18 T_DIVIDE */ 147 "non-maskable interrupt trap", /* 19 T_NMI */ 148 "overflow trap", /* 20 T_OFLOW */ 149 "FPU bounds check fault", /* 21 T_BOUND */ 150 "FPU device not available", /* 22 T_DNA */ 151 "double fault", /* 23 T_DOUBLEFLT */ 152 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 153 "invalid TSS fault", /* 25 T_TSSFLT */ 154 "segment not present fault", /* 26 T_SEGNPFLT */ 155 "stack fault", /* 27 T_STKFLT */ 156 "machine check trap", /* 28 T_MCHK */ 157 "SIMD floating-point exception", /* 29 T_XMMFLT */ 158 "reserved (unknown) fault", /* 30 T_RESERVED */ 159 }; 160 161 #ifdef KDB 162 static int kdb_on_nmi = 1; 163 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 164 &kdb_on_nmi, 0, "Go to KDB on NMI"); 165 #endif 166 static int panic_on_nmi = 1; 167 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 168 &panic_on_nmi, 0, "Panic on NMI"); 169 static int prot_fault_translation = 0; 170 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 171 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 172 173 extern char *syscallnames[]; 174 175 /* 176 * Exception, fault, and trap interface to the FreeBSD kernel. 177 * This common code is called from assembly language IDT gate entry 178 * routines that prepare a suitable stack frame, and restore this 179 * frame after the exception has been processed. 180 */ 181 182 void 183 trap(struct trapframe *frame) 184 { 185 struct thread *td = curthread; 186 struct proc *p = td->td_proc; 187 int i = 0, ucode = 0, code; 188 u_int type; 189 register_t addr = 0; 190 ksiginfo_t ksi; 191 192 PCPU_INC(cnt.v_trap); 193 type = frame->tf_trapno; 194 195 #ifdef SMP 196 /* Handler for NMI IPIs used for stopping CPUs. */ 197 if (type == T_NMI) { 198 if (ipi_nmi_handler() == 0) 199 goto out; 200 } 201 #endif /* SMP */ 202 203 #ifdef KDB 204 if (kdb_active) { 205 kdb_reenter(); 206 goto out; 207 } 208 #endif 209 210 if (type == T_RESERVED) { 211 trap_fatal(frame, 0); 212 goto out; 213 } 214 215 #ifdef HWPMC_HOOKS 216 /* 217 * CPU PMCs interrupt using an NMI. If the PMC module is 218 * active, pass the 'rip' value to the PMC module's interrupt 219 * handler. A return value of '1' from the handler means that 220 * the NMI was handled by it and we can return immediately. 221 */ 222 if (type == T_NMI && pmc_intr && 223 (*pmc_intr)(PCPU_GET(cpuid), frame)) 224 goto out; 225 #endif 226 227 if (type == T_MCHK) { 228 if (!mca_intr()) 229 trap_fatal(frame, 0); 230 goto out; 231 } 232 233 #ifdef KDTRACE_HOOKS 234 /* 235 * A trap can occur while DTrace executes a probe. Before 236 * executing the probe, DTrace blocks re-scheduling and sets 237 * a flag in it's per-cpu flags to indicate that it doesn't 238 * want to fault. On returning from the the probe, the no-fault 239 * flag is cleared and finally re-scheduling is enabled. 240 * 241 * If the DTrace kernel module has registered a trap handler, 242 * call it and if it returns non-zero, assume that it has 243 * handled the trap and modified the trap frame so that this 244 * function can return normally. 245 */ 246 if (dtrace_trap_func != NULL) 247 if ((*dtrace_trap_func)(frame, type)) 248 goto out; 249 #endif 250 251 if ((frame->tf_rflags & PSL_I) == 0) { 252 /* 253 * Buggy application or kernel code has disabled 254 * interrupts and then trapped. Enabling interrupts 255 * now is wrong, but it is better than running with 256 * interrupts disabled until they are accidentally 257 * enabled later. 258 */ 259 if (ISPL(frame->tf_cs) == SEL_UPL) 260 uprintf( 261 "pid %ld (%s): trap %d with interrupts disabled\n", 262 (long)curproc->p_pid, curthread->td_name, type); 263 else if (type != T_NMI && type != T_BPTFLT && 264 type != T_TRCTRAP) { 265 /* 266 * XXX not quite right, since this may be for a 267 * multiple fault in user mode. 268 */ 269 printf("kernel trap %d with interrupts disabled\n", 270 type); 271 272 /* 273 * We shouldn't enable interrupts while holding a 274 * spin lock or servicing an NMI. 275 */ 276 if (type != T_NMI && td->td_md.md_spinlock_count == 0) 277 enable_intr(); 278 } 279 } 280 281 code = frame->tf_err; 282 if (type == T_PAGEFLT) { 283 /* 284 * If we get a page fault while in a critical section, then 285 * it is most likely a fatal kernel page fault. The kernel 286 * is already going to panic trying to get a sleep lock to 287 * do the VM lookup, so just consider it a fatal trap so the 288 * kernel can print out a useful trap message and even get 289 * to the debugger. 290 * 291 * If we get a page fault while holding a non-sleepable 292 * lock, then it is most likely a fatal kernel page fault. 293 * If WITNESS is enabled, then it's going to whine about 294 * bogus LORs with various VM locks, so just skip to the 295 * fatal trap handling directly. 296 */ 297 if (td->td_critnest != 0 || 298 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 299 "Kernel page fault") != 0) 300 trap_fatal(frame, frame->tf_addr); 301 } 302 303 if (ISPL(frame->tf_cs) == SEL_UPL) { 304 /* user trap */ 305 306 td->td_pticks = 0; 307 td->td_frame = frame; 308 addr = frame->tf_rip; 309 if (td->td_ucred != p->p_ucred) 310 cred_update_thread(td); 311 312 switch (type) { 313 case T_PRIVINFLT: /* privileged instruction fault */ 314 i = SIGILL; 315 ucode = ILL_PRVOPC; 316 break; 317 318 case T_BPTFLT: /* bpt instruction fault */ 319 case T_TRCTRAP: /* trace trap */ 320 enable_intr(); 321 frame->tf_rflags &= ~PSL_T; 322 i = SIGTRAP; 323 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 324 break; 325 326 case T_ARITHTRAP: /* arithmetic trap */ 327 ucode = fputrap(); 328 if (ucode == -1) 329 goto userout; 330 i = SIGFPE; 331 break; 332 333 case T_PROTFLT: /* general protection fault */ 334 i = SIGBUS; 335 ucode = BUS_OBJERR; 336 break; 337 case T_STKFLT: /* stack fault */ 338 case T_SEGNPFLT: /* segment not present fault */ 339 i = SIGBUS; 340 ucode = BUS_ADRERR; 341 break; 342 case T_TSSFLT: /* invalid TSS fault */ 343 i = SIGBUS; 344 ucode = BUS_OBJERR; 345 break; 346 case T_DOUBLEFLT: /* double fault */ 347 default: 348 i = SIGBUS; 349 ucode = BUS_OBJERR; 350 break; 351 352 case T_PAGEFLT: /* page fault */ 353 addr = frame->tf_addr; 354 i = trap_pfault(frame, TRUE); 355 if (i == -1) 356 goto userout; 357 if (i == 0) 358 goto user; 359 360 if (i == SIGSEGV) 361 ucode = SEGV_MAPERR; 362 else { 363 if (prot_fault_translation == 0) { 364 /* 365 * Autodetect. 366 * This check also covers the images 367 * without the ABI-tag ELF note. 368 */ 369 if (SV_CURPROC_ABI() == 370 SV_ABI_FREEBSD && 371 p->p_osrel >= 700004) { 372 i = SIGSEGV; 373 ucode = SEGV_ACCERR; 374 } else { 375 i = SIGBUS; 376 ucode = BUS_PAGE_FAULT; 377 } 378 } else if (prot_fault_translation == 1) { 379 /* 380 * Always compat mode. 381 */ 382 i = SIGBUS; 383 ucode = BUS_PAGE_FAULT; 384 } else { 385 /* 386 * Always SIGSEGV mode. 387 */ 388 i = SIGSEGV; 389 ucode = SEGV_ACCERR; 390 } 391 } 392 break; 393 394 case T_DIVIDE: /* integer divide fault */ 395 ucode = FPE_INTDIV; 396 i = SIGFPE; 397 break; 398 399 #ifdef DEV_ISA 400 case T_NMI: 401 /* machine/parity/power fail/"kitchen sink" faults */ 402 if (isa_nmi(code) == 0) { 403 #ifdef KDB 404 /* 405 * NMI can be hooked up to a pushbutton 406 * for debugging. 407 */ 408 if (kdb_on_nmi) { 409 printf ("NMI ... going to debugger\n"); 410 kdb_trap(type, 0, frame); 411 } 412 #endif /* KDB */ 413 goto userout; 414 } else if (panic_on_nmi) 415 panic("NMI indicates hardware failure"); 416 break; 417 #endif /* DEV_ISA */ 418 419 case T_OFLOW: /* integer overflow fault */ 420 ucode = FPE_INTOVF; 421 i = SIGFPE; 422 break; 423 424 case T_BOUND: /* bounds check fault */ 425 ucode = FPE_FLTSUB; 426 i = SIGFPE; 427 break; 428 429 case T_DNA: 430 /* transparent fault (due to context switch "late") */ 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 = 0; /* XXX */ 441 i = SIGFPE; 442 break; 443 } 444 } else { 445 /* kernel trap */ 446 447 KASSERT(cold || td->td_ucred != NULL, 448 ("kernel trap doesn't have ucred")); 449 switch (type) { 450 case T_PAGEFLT: /* page fault */ 451 (void) trap_pfault(frame, FALSE); 452 goto out; 453 454 case T_DNA: 455 /* 456 * The kernel is apparently using fpu for copying. 457 * XXX this should be fatal unless the kernel has 458 * registered such use. 459 */ 460 fpudna(); 461 printf("fpudna in kernel mode!\n"); 462 goto out; 463 464 case T_STKFLT: /* stack fault */ 465 break; 466 467 case T_PROTFLT: /* general protection fault */ 468 case T_SEGNPFLT: /* segment not present fault */ 469 if (td->td_intr_nesting_level != 0) 470 break; 471 472 /* 473 * Invalid segment selectors and out of bounds 474 * %rip's and %rsp's can be set up in user mode. 475 * This causes a fault in kernel mode when the 476 * kernel tries to return to user mode. We want 477 * to get this fault so that we can fix the 478 * problem here and not have to check all the 479 * selectors and pointers when the user changes 480 * them. 481 */ 482 if (frame->tf_rip == (long)doreti_iret) { 483 frame->tf_rip = (long)doreti_iret_fault; 484 goto out; 485 } 486 if (frame->tf_rip == (long)ld_ds) { 487 frame->tf_rip = (long)ds_load_fault; 488 goto out; 489 } 490 if (frame->tf_rip == (long)ld_es) { 491 frame->tf_rip = (long)es_load_fault; 492 goto out; 493 } 494 if (frame->tf_rip == (long)ld_fs) { 495 frame->tf_rip = (long)fs_load_fault; 496 goto out; 497 } 498 if (frame->tf_rip == (long)ld_gs) { 499 frame->tf_rip = (long)gs_load_fault; 500 goto out; 501 } 502 if (frame->tf_rip == (long)ld_gsbase) { 503 frame->tf_rip = (long)gsbase_load_fault; 504 goto out; 505 } 506 if (frame->tf_rip == (long)ld_fsbase) { 507 frame->tf_rip = (long)fsbase_load_fault; 508 goto out; 509 } 510 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 511 frame->tf_rip = 512 (long)PCPU_GET(curpcb)->pcb_onfault; 513 goto out; 514 } 515 break; 516 517 case T_TSSFLT: 518 /* 519 * PSL_NT can be set in user mode and isn't cleared 520 * automatically when the kernel is entered. This 521 * causes a TSS fault when the kernel attempts to 522 * `iret' because the TSS link is uninitialized. We 523 * want to get this fault so that we can fix the 524 * problem here and not every time the kernel is 525 * entered. 526 */ 527 if (frame->tf_rflags & PSL_NT) { 528 frame->tf_rflags &= ~PSL_NT; 529 goto out; 530 } 531 break; 532 533 case T_TRCTRAP: /* trace trap */ 534 /* 535 * Ignore debug register trace traps due to 536 * accesses in the user's address space, which 537 * can happen under several conditions such as 538 * if a user sets a watchpoint on a buffer and 539 * then passes that buffer to a system call. 540 * We still want to get TRCTRAPS for addresses 541 * in kernel space because that is useful when 542 * debugging the kernel. 543 */ 544 if (user_dbreg_trap()) { 545 /* 546 * Reset breakpoint bits because the 547 * processor doesn't 548 */ 549 /* XXX check upper bits here */ 550 load_dr6(rdr6() & 0xfffffff0); 551 goto out; 552 } 553 /* 554 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 555 */ 556 case T_BPTFLT: 557 /* 558 * If KDB is enabled, let it handle the debugger trap. 559 * Otherwise, debugger traps "can't happen". 560 */ 561 #ifdef KDB 562 if (kdb_trap(type, 0, frame)) 563 goto out; 564 #endif 565 break; 566 567 #ifdef DEV_ISA 568 case T_NMI: 569 /* machine/parity/power fail/"kitchen sink" faults */ 570 if (isa_nmi(code) == 0) { 571 #ifdef KDB 572 /* 573 * NMI can be hooked up to a pushbutton 574 * for debugging. 575 */ 576 if (kdb_on_nmi) { 577 printf ("NMI ... going to debugger\n"); 578 kdb_trap(type, 0, frame); 579 } 580 #endif /* KDB */ 581 goto out; 582 } else if (panic_on_nmi == 0) 583 goto out; 584 /* FALLTHROUGH */ 585 #endif /* DEV_ISA */ 586 } 587 588 trap_fatal(frame, 0); 589 goto out; 590 } 591 592 /* Translate fault for emulators (e.g. Linux) */ 593 if (*p->p_sysent->sv_transtrap) 594 i = (*p->p_sysent->sv_transtrap)(i, type); 595 596 ksiginfo_init_trap(&ksi); 597 ksi.ksi_signo = i; 598 ksi.ksi_code = ucode; 599 ksi.ksi_trapno = type; 600 ksi.ksi_addr = (void *)addr; 601 trapsignal(td, &ksi); 602 603 user: 604 userret(td, frame); 605 mtx_assert(&Giant, MA_NOTOWNED); 606 userout: 607 out: 608 return; 609 } 610 611 static int 612 trap_pfault(frame, usermode) 613 struct trapframe *frame; 614 int usermode; 615 { 616 vm_offset_t va; 617 struct vmspace *vm = NULL; 618 vm_map_t map; 619 int rv = 0; 620 vm_prot_t ftype; 621 struct thread *td = curthread; 622 struct proc *p = td->td_proc; 623 vm_offset_t eva = frame->tf_addr; 624 625 va = trunc_page(eva); 626 if (va >= VM_MIN_KERNEL_ADDRESS) { 627 /* 628 * Don't allow user-mode faults in kernel address space. 629 */ 630 if (usermode) 631 goto nogo; 632 633 map = kernel_map; 634 } else { 635 /* 636 * This is a fault on non-kernel virtual memory. 637 * vm is initialized above to NULL. If curproc is NULL 638 * or curproc->p_vmspace is NULL the fault is fatal. 639 */ 640 if (p != NULL) 641 vm = p->p_vmspace; 642 643 if (vm == NULL) 644 goto nogo; 645 646 map = &vm->vm_map; 647 } 648 649 /* 650 * PGEX_I is defined only if the execute disable bit capability is 651 * supported and enabled. 652 */ 653 if (frame->tf_err & PGEX_W) 654 ftype = VM_PROT_WRITE; 655 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 656 ftype = VM_PROT_EXECUTE; 657 else 658 ftype = VM_PROT_READ; 659 660 if (map != kernel_map) { 661 /* 662 * Keep swapout from messing with us during this 663 * critical time. 664 */ 665 PROC_LOCK(p); 666 ++p->p_lock; 667 PROC_UNLOCK(p); 668 669 /* Fault in the user page: */ 670 rv = vm_fault(map, va, ftype, 671 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 672 : VM_FAULT_NORMAL); 673 674 PROC_LOCK(p); 675 --p->p_lock; 676 PROC_UNLOCK(p); 677 } else { 678 /* 679 * Don't have to worry about process locking or stacks in the 680 * kernel. 681 */ 682 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 683 } 684 if (rv == KERN_SUCCESS) 685 return (0); 686 nogo: 687 if (!usermode) { 688 if (td->td_intr_nesting_level == 0 && 689 PCPU_GET(curpcb)->pcb_onfault != NULL) { 690 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 691 return (0); 692 } 693 trap_fatal(frame, eva); 694 return (-1); 695 } 696 697 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 698 } 699 700 static void 701 trap_fatal(frame, eva) 702 struct trapframe *frame; 703 vm_offset_t eva; 704 { 705 int code, ss; 706 u_int type; 707 long esp; 708 struct soft_segment_descriptor softseg; 709 char *msg; 710 711 code = frame->tf_err; 712 type = frame->tf_trapno; 713 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)], 714 &softseg); 715 716 if (type <= MAX_TRAP_MSG) 717 msg = trap_msg[type]; 718 else 719 msg = "UNKNOWN"; 720 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 721 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 722 #ifdef SMP 723 /* two separate prints in case of a trap on an unmapped page */ 724 printf("cpuid = %d; ", PCPU_GET(cpuid)); 725 printf("apic id = %02x\n", PCPU_GET(apic_id)); 726 #endif 727 if (type == T_PAGEFLT) { 728 printf("fault virtual address = 0x%lx\n", eva); 729 printf("fault code = %s %s %s, %s\n", 730 code & PGEX_U ? "user" : "supervisor", 731 code & PGEX_W ? "write" : "read", 732 code & PGEX_I ? "instruction" : "data", 733 code & PGEX_P ? "protection violation" : "page not present"); 734 } 735 printf("instruction pointer = 0x%lx:0x%lx\n", 736 frame->tf_cs & 0xffff, frame->tf_rip); 737 if (ISPL(frame->tf_cs) == SEL_UPL) { 738 ss = frame->tf_ss & 0xffff; 739 esp = frame->tf_rsp; 740 } else { 741 ss = GSEL(GDATA_SEL, SEL_KPL); 742 esp = (long)&frame->tf_rsp; 743 } 744 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 745 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 746 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 747 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 748 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 749 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 750 softseg.ssd_gran); 751 printf("processor eflags = "); 752 if (frame->tf_rflags & PSL_T) 753 printf("trace trap, "); 754 if (frame->tf_rflags & PSL_I) 755 printf("interrupt enabled, "); 756 if (frame->tf_rflags & PSL_NT) 757 printf("nested task, "); 758 if (frame->tf_rflags & PSL_RF) 759 printf("resume, "); 760 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 761 printf("current process = "); 762 if (curproc) { 763 printf("%lu (%s)\n", 764 (u_long)curproc->p_pid, curthread->td_name ? 765 curthread->td_name : ""); 766 } else { 767 printf("Idle\n"); 768 } 769 770 #ifdef KDB 771 if (debugger_on_panic || kdb_active) 772 if (kdb_trap(type, 0, frame)) 773 return; 774 #endif 775 printf("trap number = %d\n", type); 776 if (type <= MAX_TRAP_MSG) 777 panic("%s", trap_msg[type]); 778 else 779 panic("unknown/reserved trap"); 780 } 781 782 /* 783 * Double fault handler. Called when a fault occurs while writing 784 * a frame for a trap/exception onto the stack. This usually occurs 785 * when the stack overflows (such is the case with infinite recursion, 786 * for example). 787 */ 788 void 789 dblfault_handler(struct trapframe *frame) 790 { 791 #ifdef KDTRACE_HOOKS 792 if (dtrace_doubletrap_func != NULL) 793 (*dtrace_doubletrap_func)(); 794 #endif 795 printf("\nFatal double fault\n"); 796 printf("rip = 0x%lx\n", frame->tf_rip); 797 printf("rsp = 0x%lx\n", frame->tf_rsp); 798 printf("rbp = 0x%lx\n", frame->tf_rbp); 799 #ifdef SMP 800 /* two separate prints in case of a trap on an unmapped page */ 801 printf("cpuid = %d; ", PCPU_GET(cpuid)); 802 printf("apic id = %02x\n", PCPU_GET(apic_id)); 803 #endif 804 panic("double fault"); 805 } 806 807 struct syscall_args { 808 u_int code; 809 struct sysent *callp; 810 register_t args[8]; 811 register_t *argp; 812 int narg; 813 }; 814 815 static int 816 fetch_syscall_args(struct thread *td, struct syscall_args *sa) 817 { 818 struct proc *p; 819 struct trapframe *frame; 820 caddr_t params; 821 int reg, regcnt, error; 822 823 p = td->td_proc; 824 frame = td->td_frame; 825 reg = 0; 826 regcnt = 6; 827 828 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 829 sa->code = frame->tf_rax; 830 831 if (p->p_sysent->sv_prepsyscall) { 832 (*p->p_sysent->sv_prepsyscall)(frame, (int *)sa->args, 833 &sa->code, ¶ms); 834 } else { 835 if (sa->code == SYS_syscall || sa->code == SYS___syscall) { 836 sa->code = frame->tf_rdi; 837 reg++; 838 regcnt--; 839 } 840 } 841 if (p->p_sysent->sv_mask) 842 sa->code &= p->p_sysent->sv_mask; 843 844 if (sa->code >= p->p_sysent->sv_size) 845 sa->callp = &p->p_sysent->sv_table[0]; 846 else 847 sa->callp = &p->p_sysent->sv_table[sa->code]; 848 849 sa->narg = sa->callp->sy_narg; 850 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]), 851 ("Too many syscall arguments!")); 852 error = 0; 853 sa->argp = &frame->tf_rdi; 854 sa->argp += reg; 855 bcopy(sa->argp, sa->args, sizeof(sa->args[0]) * regcnt); 856 if (sa->narg > regcnt) { 857 KASSERT(params != NULL, ("copyin args with no params!")); 858 error = copyin(params, &sa->args[regcnt], 859 (sa->narg - regcnt) * sizeof(sa->args[0])); 860 } 861 sa->argp = &sa->args[0]; 862 863 /* 864 * This may result in two records if debugger modified 865 * registers or memory during sleep at stop/ptrace point. 866 */ 867 #ifdef KTRACE 868 if (KTRPOINT(td, KTR_SYSCALL)) 869 ktrsyscall(sa->code, sa->narg, sa->argp); 870 #endif 871 return (error); 872 } 873 874 /* 875 * syscall - system call request C handler 876 * 877 * A system call is essentially treated as a trap. 878 */ 879 void 880 syscall(struct trapframe *frame) 881 { 882 struct thread *td; 883 struct proc *p; 884 struct syscall_args sa; 885 register_t orig_tf_rflags; 886 int error; 887 ksiginfo_t ksi; 888 889 PCPU_INC(cnt.v_syscall); 890 td = curthread; 891 p = td->td_proc; 892 td->td_syscalls++; 893 894 #ifdef DIAGNOSTIC 895 if (ISPL(frame->tf_cs) != SEL_UPL) { 896 panic("syscall"); 897 /* NOT REACHED */ 898 } 899 #endif 900 901 td->td_pticks = 0; 902 td->td_frame = frame; 903 if (td->td_ucred != p->p_ucred) 904 cred_update_thread(td); 905 orig_tf_rflags = frame->tf_rflags; 906 if (p->p_flag & P_TRACED) { 907 PROC_LOCK(p); 908 td->td_dbgflags &= ~TDB_USERWR; 909 PROC_UNLOCK(p); 910 } 911 error = fetch_syscall_args(td, &sa); 912 913 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 914 td->td_proc->p_pid, td->td_name, sa.code); 915 916 if (error == 0) { 917 td->td_retval[0] = 0; 918 td->td_retval[1] = frame->tf_rdx; 919 920 STOPEVENT(p, S_SCE, sa.narg); 921 PTRACESTOP_SC(p, td, S_PT_SCE); 922 if (td->td_dbgflags & TDB_USERWR) { 923 /* 924 * Reread syscall number and arguments if 925 * debugger modified registers or memory. 926 */ 927 error = fetch_syscall_args(td, &sa); 928 if (error != 0) 929 goto retval; 930 td->td_retval[1] = frame->tf_rdx; 931 } 932 933 #ifdef KDTRACE_HOOKS 934 /* 935 * If the systrace module has registered it's probe 936 * callback and if there is a probe active for the 937 * syscall 'entry', process the probe. 938 */ 939 if (systrace_probe_func != NULL && sa.callp->sy_entry != 0) 940 (*systrace_probe_func)(sa.callp->sy_entry, sa.code, 941 sa.callp, sa.args); 942 #endif 943 944 AUDIT_SYSCALL_ENTER(sa.code, td); 945 error = (*sa.callp->sy_call)(td, sa.argp); 946 AUDIT_SYSCALL_EXIT(error, td); 947 948 /* Save the latest error return value. */ 949 td->td_errno = error; 950 951 #ifdef KDTRACE_HOOKS 952 /* 953 * If the systrace module has registered it's probe 954 * callback and if there is a probe active for the 955 * syscall 'return', process the probe. 956 */ 957 if (systrace_probe_func != NULL && sa.callp->sy_return != 0) 958 (*systrace_probe_func)(sa.callp->sy_return, sa.code, 959 sa.callp, sa.args); 960 #endif 961 } 962 retval: 963 cpu_set_syscall_retval(td, error); 964 965 /* 966 * Traced syscall. 967 */ 968 if (orig_tf_rflags & PSL_T) { 969 frame->tf_rflags &= ~PSL_T; 970 ksiginfo_init_trap(&ksi); 971 ksi.ksi_signo = SIGTRAP; 972 ksi.ksi_code = TRAP_TRACE; 973 ksi.ksi_addr = (void *)frame->tf_rip; 974 trapsignal(td, &ksi); 975 } 976 977 /* 978 * Check for misbehavior. 979 */ 980 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 981 (sa.code >= 0 && sa.code < SYS_MAXSYSCALL) ? 982 syscallnames[sa.code] : "???"); 983 KASSERT(td->td_critnest == 0, 984 ("System call %s returning in a critical section", 985 (sa.code >= 0 && sa.code < SYS_MAXSYSCALL) ? 986 syscallnames[sa.code] : "???")); 987 KASSERT(td->td_locks == 0, 988 ("System call %s returning with %d locks held", 989 (sa.code >= 0 && sa.code < SYS_MAXSYSCALL) ? 990 syscallnames[sa.code] : "???", td->td_locks)); 991 992 /* 993 * Handle reschedule and other end-of-syscall issues 994 */ 995 userret(td, frame); 996 997 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 998 td->td_proc->p_pid, td->td_name, sa.code); 999 1000 #ifdef KTRACE 1001 if (KTRPOINT(td, KTR_SYSRET)) 1002 ktrsysret(sa.code, error, td->td_retval[0]); 1003 #endif 1004 1005 /* 1006 * This works because errno is findable through the 1007 * register set. If we ever support an emulation where this 1008 * is not the case, this code will need to be revisited. 1009 */ 1010 STOPEVENT(p, S_SCX, sa.code); 1011 1012 PTRACESTOP_SC(p, td, S_PT_SCX); 1013 1014 /* 1015 * If the user-supplied value of %rip is not a canonical 1016 * address, then some CPUs will trigger a ring 0 #GP during 1017 * the sysret instruction. However, the fault handler would 1018 * execute with the user's %gs and %rsp in ring 0 which would 1019 * not be safe. Instead, preemptively kill the thread with a 1020 * SIGBUS. 1021 */ 1022 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) { 1023 ksiginfo_init_trap(&ksi); 1024 ksi.ksi_signo = SIGBUS; 1025 ksi.ksi_code = BUS_OBJERR; 1026 ksi.ksi_trapno = T_PROTFLT; 1027 ksi.ksi_addr = (void *)td->td_frame->tf_rip; 1028 trapsignal(td, &ksi); 1029 } 1030 }
Cache object: 89096397606c9316a93537cc9cc50e58
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