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/9.0/sys/amd64/amd64/trap.c 236953 2012-06-12 12:10:10Z bz $"); 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 #endif 75 76 #include <vm/vm.h> 77 #include <vm/vm_param.h> 78 #include <vm/pmap.h> 79 #include <vm/vm_kern.h> 80 #include <vm/vm_map.h> 81 #include <vm/vm_page.h> 82 #include <vm/vm_extern.h> 83 84 #include <machine/cpu.h> 85 #include <machine/intr_machdep.h> 86 #include <x86/mca.h> 87 #include <machine/md_var.h> 88 #include <machine/pcb.h> 89 #ifdef SMP 90 #include <machine/smp.h> 91 #endif 92 #include <machine/tss.h> 93 94 #ifdef KDTRACE_HOOKS 95 #include <sys/dtrace_bsd.h> 96 97 /* 98 * This is a hook which is initialised by the dtrace module 99 * to handle traps which might occur during DTrace probe 100 * execution. 101 */ 102 dtrace_trap_func_t dtrace_trap_func; 103 104 dtrace_doubletrap_func_t dtrace_doubletrap_func; 105 106 /* 107 * This is a hook which is initialised by the systrace module 108 * when it is loaded. This keeps the DTrace syscall provider 109 * implementation opaque. 110 */ 111 systrace_probe_func_t systrace_probe_func; 112 113 /* 114 * These hooks are necessary for the pid, usdt and fasttrap providers. 115 */ 116 dtrace_fasttrap_probe_ptr_t dtrace_fasttrap_probe_ptr; 117 dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr; 118 dtrace_return_probe_ptr_t dtrace_return_probe_ptr; 119 #endif 120 121 extern void trap(struct trapframe *frame); 122 extern void syscall(struct trapframe *frame); 123 void dblfault_handler(struct trapframe *frame); 124 125 static int trap_pfault(struct trapframe *, int); 126 static void trap_fatal(struct trapframe *, vm_offset_t); 127 128 #define MAX_TRAP_MSG 33 129 static char *trap_msg[] = { 130 "", /* 0 unused */ 131 "privileged instruction fault", /* 1 T_PRIVINFLT */ 132 "", /* 2 unused */ 133 "breakpoint instruction fault", /* 3 T_BPTFLT */ 134 "", /* 4 unused */ 135 "", /* 5 unused */ 136 "arithmetic trap", /* 6 T_ARITHTRAP */ 137 "", /* 7 unused */ 138 "", /* 8 unused */ 139 "general protection fault", /* 9 T_PROTFLT */ 140 "trace trap", /* 10 T_TRCTRAP */ 141 "", /* 11 unused */ 142 "page fault", /* 12 T_PAGEFLT */ 143 "", /* 13 unused */ 144 "alignment fault", /* 14 T_ALIGNFLT */ 145 "", /* 15 unused */ 146 "", /* 16 unused */ 147 "", /* 17 unused */ 148 "integer divide fault", /* 18 T_DIVIDE */ 149 "non-maskable interrupt trap", /* 19 T_NMI */ 150 "overflow trap", /* 20 T_OFLOW */ 151 "FPU bounds check fault", /* 21 T_BOUND */ 152 "FPU device not available", /* 22 T_DNA */ 153 "double fault", /* 23 T_DOUBLEFLT */ 154 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 155 "invalid TSS fault", /* 25 T_TSSFLT */ 156 "segment not present fault", /* 26 T_SEGNPFLT */ 157 "stack fault", /* 27 T_STKFLT */ 158 "machine check trap", /* 28 T_MCHK */ 159 "SIMD floating-point exception", /* 29 T_XMMFLT */ 160 "reserved (unknown) fault", /* 30 T_RESERVED */ 161 "", /* 31 unused (reserved) */ 162 "DTrace pid return trap", /* 32 T_DTRACE_RET */ 163 "DTrace fasttrap probe trap", /* 33 T_DTRACE_PROBE */ 164 }; 165 166 #ifdef KDB 167 static int kdb_on_nmi = 1; 168 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 169 &kdb_on_nmi, 0, "Go to KDB on NMI"); 170 TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi); 171 #endif 172 static int panic_on_nmi = 1; 173 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 174 &panic_on_nmi, 0, "Panic on NMI"); 175 TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi); 176 static int prot_fault_translation = 0; 177 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 178 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 179 180 /* 181 * Exception, fault, and trap interface to the FreeBSD kernel. 182 * This common code is called from assembly language IDT gate entry 183 * routines that prepare a suitable stack frame, and restore this 184 * frame after the exception has been processed. 185 */ 186 187 void 188 trap(struct trapframe *frame) 189 { 190 struct thread *td = curthread; 191 struct proc *p = td->td_proc; 192 int i = 0, ucode = 0, code; 193 u_int type; 194 register_t addr = 0; 195 ksiginfo_t ksi; 196 197 PCPU_INC(cnt.v_trap); 198 type = frame->tf_trapno; 199 200 #ifdef SMP 201 /* Handler for NMI IPIs used for stopping CPUs. */ 202 if (type == T_NMI) { 203 if (ipi_nmi_handler() == 0) 204 goto out; 205 } 206 #endif /* SMP */ 207 208 #ifdef KDB 209 if (kdb_active) { 210 kdb_reenter(); 211 goto out; 212 } 213 #endif 214 215 if (type == T_RESERVED) { 216 trap_fatal(frame, 0); 217 goto out; 218 } 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 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 (type == T_DTRACE_PROBE || type == T_DTRACE_RET || 252 type == T_BPTFLT) { 253 struct reg regs; 254 255 fill_frame_regs(frame, ®s); 256 if (type == T_DTRACE_PROBE && 257 dtrace_fasttrap_probe_ptr != NULL && 258 dtrace_fasttrap_probe_ptr(®s) == 0) 259 goto out; 260 else if (type == T_BPTFLT && 261 dtrace_pid_probe_ptr != NULL && 262 dtrace_pid_probe_ptr(®s) == 0) 263 goto out; 264 else if (type == T_DTRACE_RET && 265 dtrace_return_probe_ptr != NULL && 266 dtrace_return_probe_ptr(®s) == 0) 267 goto out; 268 } 269 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type)) 270 goto out; 271 #endif 272 273 if ((frame->tf_rflags & PSL_I) == 0) { 274 /* 275 * Buggy application or kernel code has disabled 276 * interrupts and then trapped. Enabling interrupts 277 * now is wrong, but it is better than running with 278 * interrupts disabled until they are accidentally 279 * enabled later. 280 */ 281 if (ISPL(frame->tf_cs) == SEL_UPL) 282 uprintf( 283 "pid %ld (%s): trap %d with interrupts disabled\n", 284 (long)curproc->p_pid, curthread->td_name, type); 285 else if (type != T_NMI && type != T_BPTFLT && 286 type != T_TRCTRAP) { 287 /* 288 * XXX not quite right, since this may be for a 289 * multiple fault in user mode. 290 */ 291 printf("kernel trap %d with interrupts disabled\n", 292 type); 293 294 /* 295 * We shouldn't enable interrupts while holding a 296 * spin lock. 297 */ 298 if (td->td_md.md_spinlock_count == 0) 299 enable_intr(); 300 } 301 } 302 303 code = frame->tf_err; 304 if (type == T_PAGEFLT) { 305 /* 306 * If we get a page fault while in a critical section, then 307 * it is most likely a fatal kernel page fault. The kernel 308 * is already going to panic trying to get a sleep lock to 309 * do the VM lookup, so just consider it a fatal trap so the 310 * kernel can print out a useful trap message and even get 311 * to the debugger. 312 * 313 * If we get a page fault while holding a non-sleepable 314 * lock, then it is most likely a fatal kernel page fault. 315 * If WITNESS is enabled, then it's going to whine about 316 * bogus LORs with various VM locks, so just skip to the 317 * fatal trap handling directly. 318 */ 319 if (td->td_critnest != 0 || 320 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 321 "Kernel page fault") != 0) 322 trap_fatal(frame, frame->tf_addr); 323 } 324 325 if (ISPL(frame->tf_cs) == SEL_UPL) { 326 /* user trap */ 327 328 td->td_pticks = 0; 329 td->td_frame = frame; 330 addr = frame->tf_rip; 331 if (td->td_ucred != p->p_ucred) 332 cred_update_thread(td); 333 334 switch (type) { 335 case T_PRIVINFLT: /* privileged instruction fault */ 336 i = SIGILL; 337 ucode = ILL_PRVOPC; 338 break; 339 340 case T_BPTFLT: /* bpt instruction fault */ 341 case T_TRCTRAP: /* trace trap */ 342 enable_intr(); 343 frame->tf_rflags &= ~PSL_T; 344 i = SIGTRAP; 345 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 346 break; 347 348 case T_ARITHTRAP: /* arithmetic trap */ 349 ucode = fputrap(); 350 if (ucode == -1) 351 goto userout; 352 i = SIGFPE; 353 break; 354 355 case T_PROTFLT: /* general protection fault */ 356 i = SIGBUS; 357 ucode = BUS_OBJERR; 358 break; 359 case T_STKFLT: /* stack fault */ 360 case T_SEGNPFLT: /* segment not present fault */ 361 i = SIGBUS; 362 ucode = BUS_ADRERR; 363 break; 364 case T_TSSFLT: /* invalid TSS fault */ 365 i = SIGBUS; 366 ucode = BUS_OBJERR; 367 break; 368 case T_DOUBLEFLT: /* double fault */ 369 default: 370 i = SIGBUS; 371 ucode = BUS_OBJERR; 372 break; 373 374 case T_PAGEFLT: /* page fault */ 375 addr = frame->tf_addr; 376 i = trap_pfault(frame, TRUE); 377 if (i == -1) 378 goto userout; 379 if (i == 0) 380 goto user; 381 382 if (i == SIGSEGV) 383 ucode = SEGV_MAPERR; 384 else { 385 if (prot_fault_translation == 0) { 386 /* 387 * Autodetect. 388 * This check also covers the images 389 * without the ABI-tag ELF note. 390 */ 391 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD 392 && p->p_osrel >= P_OSREL_SIGSEGV) { 393 i = SIGSEGV; 394 ucode = SEGV_ACCERR; 395 } else { 396 i = SIGBUS; 397 ucode = BUS_PAGE_FAULT; 398 } 399 } else if (prot_fault_translation == 1) { 400 /* 401 * Always compat mode. 402 */ 403 i = SIGBUS; 404 ucode = BUS_PAGE_FAULT; 405 } else { 406 /* 407 * Always SIGSEGV mode. 408 */ 409 i = SIGSEGV; 410 ucode = SEGV_ACCERR; 411 } 412 } 413 break; 414 415 case T_DIVIDE: /* integer divide fault */ 416 ucode = FPE_INTDIV; 417 i = SIGFPE; 418 break; 419 420 #ifdef DEV_ISA 421 case T_NMI: 422 /* machine/parity/power fail/"kitchen sink" faults */ 423 if (isa_nmi(code) == 0) { 424 #ifdef KDB 425 /* 426 * NMI can be hooked up to a pushbutton 427 * for debugging. 428 */ 429 if (kdb_on_nmi) { 430 printf ("NMI ... going to debugger\n"); 431 kdb_trap(type, 0, frame); 432 } 433 #endif /* KDB */ 434 goto userout; 435 } else if (panic_on_nmi) 436 panic("NMI indicates hardware failure"); 437 break; 438 #endif /* DEV_ISA */ 439 440 case T_OFLOW: /* integer overflow fault */ 441 ucode = FPE_INTOVF; 442 i = SIGFPE; 443 break; 444 445 case T_BOUND: /* bounds check fault */ 446 ucode = FPE_FLTSUB; 447 i = SIGFPE; 448 break; 449 450 case T_DNA: 451 /* transparent fault (due to context switch "late") */ 452 KASSERT(PCB_USER_FPU(td->td_pcb), 453 ("kernel FPU ctx has leaked")); 454 fpudna(); 455 goto userout; 456 457 case T_FPOPFLT: /* FPU operand fetch fault */ 458 ucode = ILL_COPROC; 459 i = SIGILL; 460 break; 461 462 case T_XMMFLT: /* SIMD floating-point exception */ 463 ucode = 0; /* XXX */ 464 i = SIGFPE; 465 break; 466 } 467 } else { 468 /* kernel trap */ 469 470 KASSERT(cold || td->td_ucred != NULL, 471 ("kernel trap doesn't have ucred")); 472 switch (type) { 473 case T_PAGEFLT: /* page fault */ 474 (void) trap_pfault(frame, FALSE); 475 goto out; 476 477 case T_DNA: 478 KASSERT(!PCB_USER_FPU(td->td_pcb), 479 ("Unregistered use of FPU in kernel")); 480 fpudna(); 481 goto out; 482 483 case T_ARITHTRAP: /* arithmetic trap */ 484 case T_XMMFLT: /* SIMD floating-point exception */ 485 case T_FPOPFLT: /* FPU operand fetch fault */ 486 /* 487 * XXXKIB for now disable any FPU traps in kernel 488 * handler registration seems to be overkill 489 */ 490 trap_fatal(frame, 0); 491 goto out; 492 493 case T_STKFLT: /* stack fault */ 494 break; 495 496 case T_PROTFLT: /* general protection fault */ 497 case T_SEGNPFLT: /* segment not present fault */ 498 if (td->td_intr_nesting_level != 0) 499 break; 500 501 /* 502 * Invalid segment selectors and out of bounds 503 * %rip's and %rsp's can be set up in user mode. 504 * This causes a fault in kernel mode when the 505 * kernel tries to return to user mode. We want 506 * to get this fault so that we can fix the 507 * problem here and not have to check all the 508 * selectors and pointers when the user changes 509 * them. 510 */ 511 if (frame->tf_rip == (long)doreti_iret) { 512 frame->tf_rip = (long)doreti_iret_fault; 513 goto out; 514 } 515 if (frame->tf_rip == (long)ld_ds) { 516 frame->tf_rip = (long)ds_load_fault; 517 goto out; 518 } 519 if (frame->tf_rip == (long)ld_es) { 520 frame->tf_rip = (long)es_load_fault; 521 goto out; 522 } 523 if (frame->tf_rip == (long)ld_fs) { 524 frame->tf_rip = (long)fs_load_fault; 525 goto out; 526 } 527 if (frame->tf_rip == (long)ld_gs) { 528 frame->tf_rip = (long)gs_load_fault; 529 goto out; 530 } 531 if (frame->tf_rip == (long)ld_gsbase) { 532 frame->tf_rip = (long)gsbase_load_fault; 533 goto out; 534 } 535 if (frame->tf_rip == (long)ld_fsbase) { 536 frame->tf_rip = (long)fsbase_load_fault; 537 goto out; 538 } 539 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 540 frame->tf_rip = 541 (long)PCPU_GET(curpcb)->pcb_onfault; 542 goto out; 543 } 544 break; 545 546 case T_TSSFLT: 547 /* 548 * PSL_NT can be set in user mode and isn't cleared 549 * automatically when the kernel is entered. This 550 * causes a TSS fault when the kernel attempts to 551 * `iret' because the TSS link is uninitialized. We 552 * want to get this fault so that we can fix the 553 * problem here and not every time the kernel is 554 * entered. 555 */ 556 if (frame->tf_rflags & PSL_NT) { 557 frame->tf_rflags &= ~PSL_NT; 558 goto out; 559 } 560 break; 561 562 case T_TRCTRAP: /* trace trap */ 563 /* 564 * Ignore debug register trace traps due to 565 * accesses in the user's address space, which 566 * can happen under several conditions such as 567 * if a user sets a watchpoint on a buffer and 568 * then passes that buffer to a system call. 569 * We still want to get TRCTRAPS for addresses 570 * in kernel space because that is useful when 571 * debugging the kernel. 572 */ 573 if (user_dbreg_trap()) { 574 /* 575 * Reset breakpoint bits because the 576 * processor doesn't 577 */ 578 /* XXX check upper bits here */ 579 load_dr6(rdr6() & 0xfffffff0); 580 goto out; 581 } 582 /* 583 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 584 */ 585 case T_BPTFLT: 586 /* 587 * If KDB is enabled, let it handle the debugger trap. 588 * Otherwise, debugger traps "can't happen". 589 */ 590 #ifdef KDB 591 if (kdb_trap(type, 0, frame)) 592 goto out; 593 #endif 594 break; 595 596 #ifdef DEV_ISA 597 case T_NMI: 598 /* machine/parity/power fail/"kitchen sink" faults */ 599 if (isa_nmi(code) == 0) { 600 #ifdef KDB 601 /* 602 * NMI can be hooked up to a pushbutton 603 * for debugging. 604 */ 605 if (kdb_on_nmi) { 606 printf ("NMI ... going to debugger\n"); 607 kdb_trap(type, 0, frame); 608 } 609 #endif /* KDB */ 610 goto out; 611 } else if (panic_on_nmi == 0) 612 goto out; 613 /* FALLTHROUGH */ 614 #endif /* DEV_ISA */ 615 } 616 617 trap_fatal(frame, 0); 618 goto out; 619 } 620 621 /* Translate fault for emulators (e.g. Linux) */ 622 if (*p->p_sysent->sv_transtrap) 623 i = (*p->p_sysent->sv_transtrap)(i, type); 624 625 ksiginfo_init_trap(&ksi); 626 ksi.ksi_signo = i; 627 ksi.ksi_code = ucode; 628 ksi.ksi_trapno = type; 629 ksi.ksi_addr = (void *)addr; 630 trapsignal(td, &ksi); 631 632 user: 633 userret(td, frame); 634 mtx_assert(&Giant, MA_NOTOWNED); 635 KASSERT(PCB_USER_FPU(td->td_pcb), 636 ("Return from trap with kernel FPU ctx leaked")); 637 userout: 638 out: 639 return; 640 } 641 642 static int 643 trap_pfault(frame, usermode) 644 struct trapframe *frame; 645 int usermode; 646 { 647 vm_offset_t va; 648 struct vmspace *vm = NULL; 649 vm_map_t map; 650 int rv = 0; 651 vm_prot_t ftype; 652 struct thread *td = curthread; 653 struct proc *p = td->td_proc; 654 vm_offset_t eva = frame->tf_addr; 655 656 va = trunc_page(eva); 657 if (va >= VM_MIN_KERNEL_ADDRESS) { 658 /* 659 * Don't allow user-mode faults in kernel address space. 660 */ 661 if (usermode) 662 goto nogo; 663 664 map = kernel_map; 665 } else { 666 /* 667 * This is a fault on non-kernel virtual memory. 668 * vm is initialized above to NULL. If curproc is NULL 669 * or curproc->p_vmspace is NULL the fault is fatal. 670 */ 671 if (p != NULL) 672 vm = p->p_vmspace; 673 674 if (vm == NULL) 675 goto nogo; 676 677 map = &vm->vm_map; 678 679 /* 680 * When accessing a usermode address, kernel must be 681 * ready to accept the page fault, and provide a 682 * handling routine. Since accessing the address 683 * without the handler is a bug, do not try to handle 684 * it normally, and panic immediately. 685 */ 686 if (!usermode && (td->td_intr_nesting_level != 0 || 687 PCPU_GET(curpcb)->pcb_onfault == NULL)) { 688 trap_fatal(frame, eva); 689 return (-1); 690 } 691 } 692 693 /* 694 * PGEX_I is defined only if the execute disable bit capability is 695 * supported and enabled. 696 */ 697 if (frame->tf_err & PGEX_W) 698 ftype = VM_PROT_WRITE; 699 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 700 ftype = VM_PROT_EXECUTE; 701 else 702 ftype = VM_PROT_READ; 703 704 if (map != kernel_map) { 705 /* 706 * Keep swapout from messing with us during this 707 * critical time. 708 */ 709 PROC_LOCK(p); 710 ++p->p_lock; 711 PROC_UNLOCK(p); 712 713 /* Fault in the user page: */ 714 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 715 716 PROC_LOCK(p); 717 --p->p_lock; 718 PROC_UNLOCK(p); 719 } else { 720 /* 721 * Don't have to worry about process locking or stacks in the 722 * kernel. 723 */ 724 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 725 } 726 if (rv == KERN_SUCCESS) 727 return (0); 728 nogo: 729 if (!usermode) { 730 if (td->td_intr_nesting_level == 0 && 731 PCPU_GET(curpcb)->pcb_onfault != NULL) { 732 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 733 return (0); 734 } 735 trap_fatal(frame, eva); 736 return (-1); 737 } 738 739 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 740 } 741 742 static void 743 trap_fatal(frame, eva) 744 struct trapframe *frame; 745 vm_offset_t eva; 746 { 747 int code, ss; 748 u_int type; 749 long esp; 750 struct soft_segment_descriptor softseg; 751 char *msg; 752 753 code = frame->tf_err; 754 type = frame->tf_trapno; 755 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)], 756 &softseg); 757 758 if (type <= MAX_TRAP_MSG) 759 msg = trap_msg[type]; 760 else 761 msg = "UNKNOWN"; 762 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 763 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 764 #ifdef SMP 765 /* two separate prints in case of a trap on an unmapped page */ 766 printf("cpuid = %d; ", PCPU_GET(cpuid)); 767 printf("apic id = %02x\n", PCPU_GET(apic_id)); 768 #endif 769 if (type == T_PAGEFLT) { 770 printf("fault virtual address = 0x%lx\n", eva); 771 printf("fault code = %s %s %s, %s\n", 772 code & PGEX_U ? "user" : "supervisor", 773 code & PGEX_W ? "write" : "read", 774 code & PGEX_I ? "instruction" : "data", 775 code & PGEX_P ? "protection violation" : "page not present"); 776 } 777 printf("instruction pointer = 0x%lx:0x%lx\n", 778 frame->tf_cs & 0xffff, frame->tf_rip); 779 if (ISPL(frame->tf_cs) == SEL_UPL) { 780 ss = frame->tf_ss & 0xffff; 781 esp = frame->tf_rsp; 782 } else { 783 ss = GSEL(GDATA_SEL, SEL_KPL); 784 esp = (long)&frame->tf_rsp; 785 } 786 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 787 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 788 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 789 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 790 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 791 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 792 softseg.ssd_gran); 793 printf("processor eflags = "); 794 if (frame->tf_rflags & PSL_T) 795 printf("trace trap, "); 796 if (frame->tf_rflags & PSL_I) 797 printf("interrupt enabled, "); 798 if (frame->tf_rflags & PSL_NT) 799 printf("nested task, "); 800 if (frame->tf_rflags & PSL_RF) 801 printf("resume, "); 802 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 803 printf("current process = "); 804 if (curproc) { 805 printf("%lu (%s)\n", 806 (u_long)curproc->p_pid, curthread->td_name ? 807 curthread->td_name : ""); 808 } else { 809 printf("Idle\n"); 810 } 811 812 #ifdef KDB 813 if (debugger_on_panic || kdb_active) 814 if (kdb_trap(type, 0, frame)) 815 return; 816 #endif 817 printf("trap number = %d\n", type); 818 if (type <= MAX_TRAP_MSG) 819 panic("%s", trap_msg[type]); 820 else 821 panic("unknown/reserved trap"); 822 } 823 824 /* 825 * Double fault handler. Called when a fault occurs while writing 826 * a frame for a trap/exception onto the stack. This usually occurs 827 * when the stack overflows (such is the case with infinite recursion, 828 * for example). 829 */ 830 void 831 dblfault_handler(struct trapframe *frame) 832 { 833 #ifdef KDTRACE_HOOKS 834 if (dtrace_doubletrap_func != NULL) 835 (*dtrace_doubletrap_func)(); 836 #endif 837 printf("\nFatal double fault\n"); 838 printf("rip = 0x%lx\n", frame->tf_rip); 839 printf("rsp = 0x%lx\n", frame->tf_rsp); 840 printf("rbp = 0x%lx\n", frame->tf_rbp); 841 #ifdef SMP 842 /* two separate prints in case of a trap on an unmapped page */ 843 printf("cpuid = %d; ", PCPU_GET(cpuid)); 844 printf("apic id = %02x\n", PCPU_GET(apic_id)); 845 #endif 846 panic("double fault"); 847 } 848 849 int 850 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 851 { 852 struct proc *p; 853 struct trapframe *frame; 854 register_t *argp; 855 caddr_t params; 856 int reg, regcnt, error; 857 858 p = td->td_proc; 859 frame = td->td_frame; 860 reg = 0; 861 regcnt = 6; 862 863 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 864 sa->code = frame->tf_rax; 865 866 if (sa->code == SYS_syscall || sa->code == SYS___syscall) { 867 sa->code = frame->tf_rdi; 868 reg++; 869 regcnt--; 870 } 871 if (p->p_sysent->sv_mask) 872 sa->code &= p->p_sysent->sv_mask; 873 874 if (sa->code >= p->p_sysent->sv_size) 875 sa->callp = &p->p_sysent->sv_table[0]; 876 else 877 sa->callp = &p->p_sysent->sv_table[sa->code]; 878 879 sa->narg = sa->callp->sy_narg; 880 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]), 881 ("Too many syscall arguments!")); 882 error = 0; 883 argp = &frame->tf_rdi; 884 argp += reg; 885 bcopy(argp, sa->args, sizeof(sa->args[0]) * regcnt); 886 if (sa->narg > regcnt) { 887 KASSERT(params != NULL, ("copyin args with no params!")); 888 error = copyin(params, &sa->args[regcnt], 889 (sa->narg - regcnt) * sizeof(sa->args[0])); 890 } 891 892 if (error == 0) { 893 td->td_retval[0] = 0; 894 td->td_retval[1] = frame->tf_rdx; 895 } 896 897 return (error); 898 } 899 900 #include "../../kern/subr_syscall.c" 901 902 /* 903 * syscall - system call request C handler 904 * 905 * A system call is essentially treated as a trap. 906 */ 907 void 908 amd64_syscall(struct thread *td, int traced) 909 { 910 struct syscall_args sa; 911 int error; 912 ksiginfo_t ksi; 913 914 #ifdef DIAGNOSTIC 915 if (ISPL(td->td_frame->tf_cs) != SEL_UPL) { 916 panic("syscall"); 917 /* NOT REACHED */ 918 } 919 #endif 920 error = syscallenter(td, &sa); 921 922 /* 923 * Traced syscall. 924 */ 925 if (__predict_false(traced)) { 926 td->td_frame->tf_rflags &= ~PSL_T; 927 ksiginfo_init_trap(&ksi); 928 ksi.ksi_signo = SIGTRAP; 929 ksi.ksi_code = TRAP_TRACE; 930 ksi.ksi_addr = (void *)td->td_frame->tf_rip; 931 trapsignal(td, &ksi); 932 } 933 934 KASSERT(PCB_USER_FPU(td->td_pcb), 935 ("System call %s returing with kernel FPU ctx leaked", 936 syscallname(td->td_proc, sa.code))); 937 KASSERT(td->td_pcb->pcb_save == &td->td_pcb->pcb_user_save, 938 ("System call %s returning with mangled pcb_save", 939 syscallname(td->td_proc, sa.code))); 940 941 syscallret(td, error, &sa); 942 943 /* 944 * If the user-supplied value of %rip is not a canonical 945 * address, then some CPUs will trigger a ring 0 #GP during 946 * the sysret instruction. However, the fault handler would 947 * execute with the user's %gs and %rsp in ring 0 which would 948 * not be safe. Instead, preemptively kill the thread with a 949 * SIGBUS. 950 */ 951 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) { 952 ksiginfo_init_trap(&ksi); 953 ksi.ksi_signo = SIGBUS; 954 ksi.ksi_code = BUS_OBJERR; 955 ksi.ksi_trapno = T_PROTFLT; 956 ksi.ksi_addr = (void *)td->td_frame->tf_rip; 957 trapsignal(td, &ksi); 958 } 959 }
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