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/7.3/sys/amd64/amd64/trap.c 198589 2009-10-29 14:34:02Z jhb $"); 42 43 /* 44 * AMD64 Trap and System call handling 45 */ 46 47 #include "opt_clock.h" 48 #include "opt_compat.h" 49 #include "opt_cpu.h" 50 #include "opt_hwpmc_hooks.h" 51 #include "opt_isa.h" 52 #include "opt_kdb.h" 53 #include "opt_kdtrace.h" 54 #include "opt_ktrace.h" 55 56 #include <sys/param.h> 57 #include <sys/bus.h> 58 #include <sys/systm.h> 59 #include <sys/proc.h> 60 #include <sys/pioctl.h> 61 #include <sys/ptrace.h> 62 #include <sys/kdb.h> 63 #include <sys/kernel.h> 64 #include <sys/ktr.h> 65 #include <sys/lock.h> 66 #include <sys/mutex.h> 67 #include <sys/resourcevar.h> 68 #include <sys/signalvar.h> 69 #include <sys/syscall.h> 70 #include <sys/sysctl.h> 71 #include <sys/sysent.h> 72 #include <sys/uio.h> 73 #include <sys/vmmeter.h> 74 #ifdef KTRACE 75 #include <sys/ktrace.h> 76 #endif 77 #ifdef HWPMC_HOOKS 78 #include <sys/pmckern.h> 79 #endif 80 #include <security/audit/audit.h> 81 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <vm/pmap.h> 85 #include <vm/vm_kern.h> 86 #include <vm/vm_map.h> 87 #include <vm/vm_page.h> 88 #include <vm/vm_extern.h> 89 90 #include <machine/cpu.h> 91 #include <machine/intr_machdep.h> 92 #include <machine/mca.h> 93 #include <machine/md_var.h> 94 #include <machine/pcb.h> 95 #ifdef SMP 96 #include <machine/smp.h> 97 #endif 98 #include <machine/tss.h> 99 100 #ifdef KDTRACE_HOOKS 101 #include <sys/dtrace_bsd.h> 102 103 /* 104 * This is a hook which is initialised by the dtrace module 105 * to handle traps which might occur during DTrace probe 106 * execution. 107 */ 108 dtrace_trap_func_t dtrace_trap_func; 109 110 dtrace_doubletrap_func_t dtrace_doubletrap_func; 111 112 /* 113 * This is a hook which is initialised by the systrace module 114 * when it is loaded. This keeps the DTrace syscall provider 115 * implementation opaque. 116 */ 117 systrace_probe_func_t systrace_probe_func; 118 #endif 119 120 /* Defined in amd64/amd64/elf_machdep.c. */ 121 extern struct sysentvec elf64_freebsd_sysvec; 122 #ifdef COMPAT_IA32 123 /* Defined in compat/ia32/ia32_sysvec.c. */ 124 extern struct sysentvec ia32_freebsd_sysvec; 125 #endif 126 127 extern void trap(struct trapframe *frame); 128 extern void syscall(struct trapframe *frame); 129 void dblfault_handler(struct trapframe *frame); 130 131 static int trap_pfault(struct trapframe *, int); 132 static void trap_fatal(struct trapframe *, vm_offset_t); 133 134 #define MAX_TRAP_MSG 30 135 static char *trap_msg[] = { 136 "", /* 0 unused */ 137 "privileged instruction fault", /* 1 T_PRIVINFLT */ 138 "", /* 2 unused */ 139 "breakpoint instruction fault", /* 3 T_BPTFLT */ 140 "", /* 4 unused */ 141 "", /* 5 unused */ 142 "arithmetic trap", /* 6 T_ARITHTRAP */ 143 "", /* 7 unused */ 144 "", /* 8 unused */ 145 "general protection fault", /* 9 T_PROTFLT */ 146 "trace trap", /* 10 T_TRCTRAP */ 147 "", /* 11 unused */ 148 "page fault", /* 12 T_PAGEFLT */ 149 "", /* 13 unused */ 150 "alignment fault", /* 14 T_ALIGNFLT */ 151 "", /* 15 unused */ 152 "", /* 16 unused */ 153 "", /* 17 unused */ 154 "integer divide fault", /* 18 T_DIVIDE */ 155 "non-maskable interrupt trap", /* 19 T_NMI */ 156 "overflow trap", /* 20 T_OFLOW */ 157 "FPU bounds check fault", /* 21 T_BOUND */ 158 "FPU device not available", /* 22 T_DNA */ 159 "double fault", /* 23 T_DOUBLEFLT */ 160 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 161 "invalid TSS fault", /* 25 T_TSSFLT */ 162 "segment not present fault", /* 26 T_SEGNPFLT */ 163 "stack fault", /* 27 T_STKFLT */ 164 "machine check trap", /* 28 T_MCHK */ 165 "SIMD floating-point exception", /* 29 T_XMMFLT */ 166 "reserved (unknown) fault", /* 30 T_RESERVED */ 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 #endif 174 static int panic_on_nmi = 1; 175 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 176 &panic_on_nmi, 0, "Panic on NMI"); 177 static int prot_fault_translation = 0; 178 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 179 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 180 181 extern char *syscallnames[]; 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 #ifdef STOP_NMI 205 /* Handler for NMI IPIs used for stopping CPUs. */ 206 if (type == T_NMI) { 207 if (ipi_nmi_handler() == 0) 208 goto out; 209 } 210 #endif /* STOP_NMI */ 211 #endif /* SMP */ 212 213 #ifdef KDB 214 if (kdb_active) { 215 kdb_reenter(); 216 goto out; 217 } 218 #endif 219 220 #ifdef HWPMC_HOOKS 221 /* 222 * CPU PMCs interrupt using an NMI. If the PMC module is 223 * active, pass the 'rip' value to the PMC module's interrupt 224 * handler. A return value of '1' from the handler means that 225 * the NMI was handled by it and we can return immediately. 226 */ 227 if (type == T_NMI && pmc_intr && 228 (*pmc_intr)(PCPU_GET(cpuid), frame)) 229 goto out; 230 #endif 231 232 if (type == T_MCHK) { 233 if (!mca_intr()) 234 trap_fatal(frame, 0); 235 goto out; 236 } 237 238 #ifdef KDTRACE_HOOKS 239 /* 240 * A trap can occur while DTrace executes a probe. Before 241 * executing the probe, DTrace blocks re-scheduling and sets 242 * a flag in it's per-cpu flags to indicate that it doesn't 243 * want to fault. On returning from the the probe, the no-fault 244 * flag is cleared and finally re-scheduling is enabled. 245 * 246 * If the DTrace kernel module has registered a trap handler, 247 * call it and if it returns non-zero, assume that it has 248 * handled the trap and modified the trap frame so that this 249 * function can return normally. 250 */ 251 if (dtrace_trap_func != NULL) 252 if ((*dtrace_trap_func)(frame, type)) 253 goto out; 254 #endif 255 256 if ((frame->tf_rflags & PSL_I) == 0) { 257 /* 258 * Buggy application or kernel code has disabled 259 * interrupts and then trapped. Enabling interrupts 260 * now is wrong, but it is better than running with 261 * interrupts disabled until they are accidentally 262 * enabled later. 263 */ 264 if (ISPL(frame->tf_cs) == SEL_UPL) 265 printf( 266 "pid %ld (%s): trap %d with interrupts disabled\n", 267 (long)curproc->p_pid, curproc->p_comm, type); 268 else if (type != T_NMI && type != T_BPTFLT && 269 type != T_TRCTRAP) { 270 /* 271 * XXX not quite right, since this may be for a 272 * multiple fault in user mode. 273 */ 274 printf("kernel trap %d with interrupts disabled\n", 275 type); 276 /* 277 * We shouldn't enable interrupts while holding a 278 * spin lock or servicing an NMI. 279 */ 280 if (type != T_NMI && td->td_md.md_spinlock_count == 0) 281 enable_intr(); 282 } 283 } 284 285 code = frame->tf_err; 286 if (type == T_PAGEFLT) { 287 /* 288 * If we get a page fault while in a critical section, then 289 * it is most likely a fatal kernel page fault. The kernel 290 * is already going to panic trying to get a sleep lock to 291 * do the VM lookup, so just consider it a fatal trap so the 292 * kernel can print out a useful trap message and even get 293 * to the debugger. 294 * 295 * If we get a page fault while holding a non-sleepable 296 * lock, then it is most likely a fatal kernel page fault. 297 * If WITNESS is enabled, then it's going to whine about 298 * bogus LORs with various VM locks, so just skip to the 299 * fatal trap handling directly. 300 */ 301 if (td->td_critnest != 0 || 302 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 303 "Kernel page fault") != 0) 304 trap_fatal(frame, frame->tf_addr); 305 } 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 #ifdef KSE 359 if (td->td_pflags & TDP_SA) 360 thread_user_enter(td); 361 #endif 362 i = trap_pfault(frame, TRUE); 363 if (i == -1) 364 goto userout; 365 if (i == 0) 366 goto user; 367 368 if (i == SIGSEGV) 369 ucode = SEGV_MAPERR; 370 else { 371 if (prot_fault_translation == 0) { 372 /* 373 * Autodetect. 374 * This check also covers the images 375 * without the ABI-tag ELF note. 376 */ 377 if ((curproc->p_sysent == 378 &elf64_freebsd_sysvec 379 #ifdef COMPAT_IA32 380 || curproc->p_sysent == 381 &ia32_freebsd_sysvec 382 #endif 383 ) && p->p_osrel >= 700004) { 384 i = SIGSEGV; 385 ucode = SEGV_ACCERR; 386 } else { 387 i = SIGBUS; 388 ucode = BUS_PAGE_FAULT; 389 } 390 } else if (prot_fault_translation == 1) { 391 /* 392 * Always compat mode. 393 */ 394 i = SIGBUS; 395 ucode = BUS_PAGE_FAULT; 396 } else { 397 /* 398 * Always SIGSEGV mode. 399 */ 400 i = SIGSEGV; 401 ucode = SEGV_ACCERR; 402 } 403 } 404 break; 405 406 case T_DIVIDE: /* integer divide fault */ 407 ucode = FPE_INTDIV; 408 i = SIGFPE; 409 break; 410 411 #ifdef DEV_ISA 412 case T_NMI: 413 /* machine/parity/power fail/"kitchen sink" faults */ 414 /* XXX Giant */ 415 if (isa_nmi(code) == 0) { 416 #ifdef KDB 417 /* 418 * NMI can be hooked up to a pushbutton 419 * for debugging. 420 */ 421 if (kdb_on_nmi) { 422 printf ("NMI ... going to debugger\n"); 423 kdb_trap(type, 0, frame); 424 } 425 #endif /* KDB */ 426 goto userout; 427 } else if (panic_on_nmi) 428 panic("NMI indicates hardware failure"); 429 break; 430 #endif /* DEV_ISA */ 431 432 case T_OFLOW: /* integer overflow fault */ 433 ucode = FPE_INTOVF; 434 i = SIGFPE; 435 break; 436 437 case T_BOUND: /* bounds check fault */ 438 ucode = FPE_FLTSUB; 439 i = SIGFPE; 440 break; 441 442 case T_DNA: 443 /* transparent fault (due to context switch "late") */ 444 fpudna(); 445 goto userout; 446 447 case T_FPOPFLT: /* FPU operand fetch fault */ 448 ucode = ILL_COPROC; 449 i = SIGILL; 450 break; 451 452 case T_XMMFLT: /* SIMD floating-point exception */ 453 ucode = 0; /* XXX */ 454 i = SIGFPE; 455 break; 456 } 457 } else { 458 /* kernel trap */ 459 460 KASSERT(cold || td->td_ucred != NULL, 461 ("kernel trap doesn't have ucred")); 462 switch (type) { 463 case T_PAGEFLT: /* page fault */ 464 (void) trap_pfault(frame, FALSE); 465 goto out; 466 467 case T_DNA: 468 /* 469 * The kernel is apparently using fpu for copying. 470 * XXX this should be fatal unless the kernel has 471 * registered such use. 472 */ 473 fpudna(); 474 printf("fpudna in kernel mode!\n"); 475 goto out; 476 477 case T_STKFLT: /* stack fault */ 478 break; 479 480 case T_PROTFLT: /* general protection fault */ 481 case T_SEGNPFLT: /* segment not present fault */ 482 if (td->td_intr_nesting_level != 0) 483 break; 484 485 /* 486 * Invalid segment selectors and out of bounds 487 * %rip's and %rsp's can be set up in user mode. 488 * This causes a fault in kernel mode when the 489 * kernel tries to return to user mode. We want 490 * to get this fault so that we can fix the 491 * problem here and not have to check all the 492 * selectors and pointers when the user changes 493 * them. 494 */ 495 if (frame->tf_rip == (long)doreti_iret) { 496 frame->tf_rip = (long)doreti_iret_fault; 497 goto out; 498 } 499 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 500 frame->tf_rip = 501 (long)PCPU_GET(curpcb)->pcb_onfault; 502 goto out; 503 } 504 break; 505 506 case T_TSSFLT: 507 /* 508 * PSL_NT can be set in user mode and isn't cleared 509 * automatically when the kernel is entered. This 510 * causes a TSS fault when the kernel attempts to 511 * `iret' because the TSS link is uninitialized. We 512 * want to get this fault so that we can fix the 513 * problem here and not every time the kernel is 514 * entered. 515 */ 516 if (frame->tf_rflags & PSL_NT) { 517 frame->tf_rflags &= ~PSL_NT; 518 goto out; 519 } 520 break; 521 522 case T_TRCTRAP: /* trace trap */ 523 /* 524 * Ignore debug register trace traps due to 525 * accesses in the user's address space, which 526 * can happen under several conditions such as 527 * if a user sets a watchpoint on a buffer and 528 * then passes that buffer to a system call. 529 * We still want to get TRCTRAPS for addresses 530 * in kernel space because that is useful when 531 * debugging the kernel. 532 */ 533 if (user_dbreg_trap()) { 534 /* 535 * Reset breakpoint bits because the 536 * processor doesn't 537 */ 538 /* XXX check upper bits here */ 539 load_dr6(rdr6() & 0xfffffff0); 540 goto out; 541 } 542 /* 543 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 544 */ 545 case T_BPTFLT: 546 /* 547 * If KDB is enabled, let it handle the debugger trap. 548 * Otherwise, debugger traps "can't happen". 549 */ 550 #ifdef KDB 551 if (kdb_trap(type, 0, frame)) 552 goto out; 553 #endif 554 break; 555 556 #ifdef DEV_ISA 557 case T_NMI: 558 /* XXX Giant */ 559 /* machine/parity/power fail/"kitchen sink" faults */ 560 if (isa_nmi(code) == 0) { 561 #ifdef KDB 562 /* 563 * NMI can be hooked up to a pushbutton 564 * for debugging. 565 */ 566 if (kdb_on_nmi) { 567 printf ("NMI ... going to debugger\n"); 568 kdb_trap(type, 0, frame); 569 } 570 #endif /* KDB */ 571 goto out; 572 } else if (panic_on_nmi == 0) 573 goto out; 574 /* FALLTHROUGH */ 575 #endif /* DEV_ISA */ 576 } 577 578 trap_fatal(frame, 0); 579 goto out; 580 } 581 582 /* Translate fault for emulators (e.g. Linux) */ 583 if (*p->p_sysent->sv_transtrap) 584 i = (*p->p_sysent->sv_transtrap)(i, type); 585 586 ksiginfo_init_trap(&ksi); 587 ksi.ksi_signo = i; 588 ksi.ksi_code = ucode; 589 ksi.ksi_trapno = type; 590 ksi.ksi_addr = (void *)addr; 591 trapsignal(td, &ksi); 592 593 #ifdef DEBUG 594 if (type <= MAX_TRAP_MSG) { 595 uprintf("fatal process exception: %s", 596 trap_msg[type]); 597 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 598 uprintf(", fault VA = 0x%lx", frame->tf_addr); 599 uprintf("\n"); 600 } 601 #endif 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, curproc->p_comm ? 765 curproc->p_comm : ""); 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 /* 808 * syscall - system call request C handler 809 * 810 * A system call is essentially treated as a trap. 811 */ 812 void 813 syscall(struct trapframe *frame) 814 { 815 caddr_t params; 816 struct sysent *callp; 817 struct thread *td = curthread; 818 struct proc *p = td->td_proc; 819 register_t orig_tf_rflags; 820 int error; 821 int narg; 822 register_t args[8]; 823 register_t *argp; 824 u_int code; 825 int reg, regcnt; 826 ksiginfo_t ksi; 827 828 PCPU_INC(cnt.v_syscall); 829 830 #ifdef DIAGNOSTIC 831 if (ISPL(frame->tf_cs) != SEL_UPL) { 832 panic("syscall"); 833 /* NOT REACHED */ 834 } 835 #endif 836 837 reg = 0; 838 regcnt = 6; 839 td->td_pticks = 0; 840 td->td_frame = frame; 841 if (td->td_ucred != p->p_ucred) 842 cred_update_thread(td); 843 #ifdef KSE 844 if (p->p_flag & P_SA) 845 thread_user_enter(td); 846 #endif 847 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 848 code = frame->tf_rax; 849 orig_tf_rflags = frame->tf_rflags; 850 851 if (p->p_sysent->sv_prepsyscall) { 852 /* 853 * The prep code is MP aware. 854 */ 855 (*p->p_sysent->sv_prepsyscall)(frame, (int *)args, &code, ¶ms); 856 } else { 857 if (code == SYS_syscall || code == SYS___syscall) { 858 code = frame->tf_rdi; 859 reg++; 860 regcnt--; 861 } 862 } 863 864 if (p->p_sysent->sv_mask) 865 code &= p->p_sysent->sv_mask; 866 867 if (code >= p->p_sysent->sv_size) 868 callp = &p->p_sysent->sv_table[0]; 869 else 870 callp = &p->p_sysent->sv_table[code]; 871 872 narg = callp->sy_narg; 873 874 /* 875 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 876 */ 877 KASSERT(narg <= sizeof(args) / sizeof(args[0]), 878 ("Too many syscall arguments!")); 879 error = 0; 880 argp = &frame->tf_rdi; 881 argp += reg; 882 bcopy(argp, args, sizeof(args[0]) * regcnt); 883 if (narg > regcnt) { 884 KASSERT(params != NULL, ("copyin args with no params!")); 885 error = copyin(params, &args[regcnt], 886 (narg - regcnt) * sizeof(args[0])); 887 } 888 argp = &args[0]; 889 890 #ifdef KTRACE 891 if (KTRPOINT(td, KTR_SYSCALL)) 892 ktrsyscall(code, narg, argp); 893 #endif 894 895 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 896 td->td_proc->p_pid, td->td_proc->p_comm, code); 897 898 td->td_syscalls++; 899 900 if (error == 0) { 901 td->td_retval[0] = 0; 902 td->td_retval[1] = frame->tf_rdx; 903 904 STOPEVENT(p, S_SCE, narg); 905 906 PTRACESTOP_SC(p, td, S_PT_SCE); 907 908 #ifdef KDTRACE_HOOKS 909 /* 910 * If the systrace module has registered it's probe 911 * callback and if there is a probe active for the 912 * syscall 'entry', process the probe. 913 */ 914 if (systrace_probe_func != NULL && callp->sy_entry != 0) 915 (*systrace_probe_func)(callp->sy_entry, code, callp, 916 args); 917 #endif 918 919 AUDIT_SYSCALL_ENTER(code, td); 920 error = (*callp->sy_call)(td, argp); 921 AUDIT_SYSCALL_EXIT(error, td); 922 923 /* Save the latest error return value. */ 924 td->td_errno = error; 925 926 #ifdef KDTRACE_HOOKS 927 /* 928 * If the systrace module has registered it's probe 929 * callback and if there is a probe active for the 930 * syscall 'return', process the probe. 931 */ 932 if (systrace_probe_func != NULL && callp->sy_return != 0) 933 (*systrace_probe_func)(callp->sy_return, code, callp, 934 args); 935 #endif 936 } 937 938 switch (error) { 939 case 0: 940 frame->tf_rax = td->td_retval[0]; 941 frame->tf_rdx = td->td_retval[1]; 942 frame->tf_rflags &= ~PSL_C; 943 break; 944 945 case ERESTART: 946 /* 947 * Reconstruct pc, we know that 'syscall' is 2 bytes. 948 * We have to do a full context restore so that %r10 949 * (which was holding the value of %rcx) is restored for 950 * the next iteration. 951 */ 952 frame->tf_rip -= frame->tf_err; 953 frame->tf_r10 = frame->tf_rcx; 954 td->td_pcb->pcb_flags |= PCB_FULLCTX; 955 break; 956 957 case EJUSTRETURN: 958 break; 959 960 default: 961 if (p->p_sysent->sv_errsize) { 962 if (error >= p->p_sysent->sv_errsize) 963 error = -1; /* XXX */ 964 else 965 error = p->p_sysent->sv_errtbl[error]; 966 } 967 frame->tf_rax = error; 968 frame->tf_rflags |= PSL_C; 969 break; 970 } 971 972 /* 973 * Traced syscall. 974 */ 975 if (orig_tf_rflags & PSL_T) { 976 frame->tf_rflags &= ~PSL_T; 977 ksiginfo_init_trap(&ksi); 978 ksi.ksi_signo = SIGTRAP; 979 ksi.ksi_code = TRAP_TRACE; 980 ksi.ksi_addr = (void *)frame->tf_rip; 981 trapsignal(td, &ksi); 982 } 983 984 /* 985 * Check for misbehavior. 986 */ 987 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 988 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 989 KASSERT(td->td_critnest == 0, 990 ("System call %s returning in a critical section", 991 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???")); 992 KASSERT(td->td_locks == 0, 993 ("System call %s returning with %d locks held", 994 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???", 995 td->td_locks)); 996 997 /* 998 * Handle reschedule and other end-of-syscall issues 999 */ 1000 userret(td, frame); 1001 1002 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 1003 td->td_proc->p_pid, td->td_proc->p_comm, code); 1004 1005 #ifdef KTRACE 1006 if (KTRPOINT(td, KTR_SYSRET)) 1007 ktrsysret(code, error, td->td_retval[0]); 1008 #endif 1009 1010 /* 1011 * This works because errno is findable through the 1012 * register set. If we ever support an emulation where this 1013 * is not the case, this code will need to be revisited. 1014 */ 1015 STOPEVENT(p, S_SCX, code); 1016 1017 PTRACESTOP_SC(p, td, S_PT_SCX); 1018 }
Cache object: 3c38d136baa1765c9c60cbe60955ddde
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