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("$FreeBSD$"); 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_ktrace.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 KTRACE 73 #include <sys/ktrace.h> 74 #endif 75 #ifdef HWPMC_HOOKS 76 #include <sys/pmckern.h> 77 #endif 78 #include <security/audit/audit.h> 79 80 #include <vm/vm.h> 81 #include <vm/vm_param.h> 82 #include <vm/pmap.h> 83 #include <vm/vm_kern.h> 84 #include <vm/vm_map.h> 85 #include <vm/vm_page.h> 86 #include <vm/vm_extern.h> 87 88 #include <machine/cpu.h> 89 #include <machine/intr_machdep.h> 90 #include <machine/md_var.h> 91 #include <machine/pcb.h> 92 #ifdef SMP 93 #include <machine/smp.h> 94 #endif 95 #include <machine/tss.h> 96 97 extern void trap(struct trapframe *frame); 98 extern void syscall(struct trapframe *frame); 99 void dblfault_handler(struct trapframe *frame); 100 101 static int trap_pfault(struct trapframe *, int); 102 static void trap_fatal(struct trapframe *, vm_offset_t); 103 104 #define MAX_TRAP_MSG 30 105 static char *trap_msg[] = { 106 "", /* 0 unused */ 107 "privileged instruction fault", /* 1 T_PRIVINFLT */ 108 "", /* 2 unused */ 109 "breakpoint instruction fault", /* 3 T_BPTFLT */ 110 "", /* 4 unused */ 111 "", /* 5 unused */ 112 "arithmetic trap", /* 6 T_ARITHTRAP */ 113 "", /* 7 unused */ 114 "", /* 8 unused */ 115 "general protection fault", /* 9 T_PROTFLT */ 116 "trace trap", /* 10 T_TRCTRAP */ 117 "", /* 11 unused */ 118 "page fault", /* 12 T_PAGEFLT */ 119 "", /* 13 unused */ 120 "alignment fault", /* 14 T_ALIGNFLT */ 121 "", /* 15 unused */ 122 "", /* 16 unused */ 123 "", /* 17 unused */ 124 "integer divide fault", /* 18 T_DIVIDE */ 125 "non-maskable interrupt trap", /* 19 T_NMI */ 126 "overflow trap", /* 20 T_OFLOW */ 127 "FPU bounds check fault", /* 21 T_BOUND */ 128 "FPU device not available", /* 22 T_DNA */ 129 "double fault", /* 23 T_DOUBLEFLT */ 130 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 131 "invalid TSS fault", /* 25 T_TSSFLT */ 132 "segment not present fault", /* 26 T_SEGNPFLT */ 133 "stack fault", /* 27 T_STKFLT */ 134 "machine check trap", /* 28 T_MCHK */ 135 "SIMD floating-point exception", /* 29 T_XMMFLT */ 136 "reserved (unknown) fault", /* 30 T_RESERVED */ 137 }; 138 139 #ifdef KDB 140 static int kdb_on_nmi = 1; 141 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW, 142 &kdb_on_nmi, 0, "Go to KDB on NMI"); 143 #endif 144 static int panic_on_nmi = 1; 145 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 146 &panic_on_nmi, 0, "Panic on NMI"); 147 static int prot_fault_translation = 0; 148 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW, 149 &prot_fault_translation, 0, "Select signal to deliver on protection fault"); 150 151 extern char *syscallnames[]; 152 153 /* 154 * Exception, fault, and trap interface to the FreeBSD kernel. 155 * This common code is called from assembly language IDT gate entry 156 * routines that prepare a suitable stack frame, and restore this 157 * frame after the exception has been processed. 158 */ 159 160 void 161 trap(struct trapframe *frame) 162 { 163 struct thread *td = curthread; 164 struct proc *p = td->td_proc; 165 int i = 0, ucode = 0, code; 166 u_int type; 167 register_t addr = 0; 168 ksiginfo_t ksi; 169 170 PCPU_INC(cnt.v_trap); 171 type = frame->tf_trapno; 172 173 #ifdef SMP 174 #ifdef STOP_NMI 175 /* Handler for NMI IPIs used for stopping CPUs. */ 176 if (type == T_NMI) { 177 if (ipi_nmi_handler() == 0) 178 goto out; 179 } 180 #endif /* STOP_NMI */ 181 #endif /* SMP */ 182 183 #ifdef KDB 184 if (kdb_active) { 185 kdb_reenter(); 186 goto out; 187 } 188 #endif 189 190 #ifdef HWPMC_HOOKS 191 /* 192 * CPU PMCs interrupt using an NMI. If the PMC module is 193 * active, pass the 'rip' value to the PMC module's interrupt 194 * handler. A return value of '1' from the handler means that 195 * the NMI was handled by it and we can return immediately. 196 */ 197 if (type == T_NMI && pmc_intr && 198 (*pmc_intr)(PCPU_GET(cpuid), (uintptr_t) frame->tf_rip, 199 TRAPF_USERMODE(frame))) 200 goto out; 201 #endif 202 203 if ((frame->tf_rflags & PSL_I) == 0) { 204 /* 205 * Buggy application or kernel code has disabled 206 * interrupts and then trapped. Enabling interrupts 207 * now is wrong, but it is better than running with 208 * interrupts disabled until they are accidentally 209 * enabled later. 210 */ 211 if (ISPL(frame->tf_cs) == SEL_UPL) 212 printf( 213 "pid %ld (%s): trap %d with interrupts disabled\n", 214 (long)curproc->p_pid, curproc->p_comm, type); 215 else if (type != T_NMI && type != T_BPTFLT && 216 type != T_TRCTRAP) { 217 /* 218 * XXX not quite right, since this may be for a 219 * multiple fault in user mode. 220 */ 221 printf("kernel trap %d with interrupts disabled\n", 222 type); 223 /* 224 * We shouldn't enable interrupts while holding a 225 * spin lock or servicing an NMI. 226 */ 227 if (type != T_NMI && td->td_md.md_spinlock_count == 0) 228 enable_intr(); 229 } 230 } 231 232 code = frame->tf_err; 233 if (type == T_PAGEFLT) { 234 /* 235 * If we get a page fault while in a critical section, then 236 * it is most likely a fatal kernel page fault. The kernel 237 * is already going to panic trying to get a sleep lock to 238 * do the VM lookup, so just consider it a fatal trap so the 239 * kernel can print out a useful trap message and even get 240 * to the debugger. 241 * 242 * If we get a page fault while holding a non-sleepable 243 * lock, then it is most likely a fatal kernel page fault. 244 * If WITNESS is enabled, then it's going to whine about 245 * bogus LORs with various VM locks, so just skip to the 246 * fatal trap handling directly. 247 */ 248 if (td->td_critnest != 0 || 249 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL, 250 "Kernel page fault") != 0) 251 trap_fatal(frame, frame->tf_addr); 252 } 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 frame->tf_rflags &= ~PSL_T; 273 i = SIGTRAP; 274 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT); 275 break; 276 277 case T_ARITHTRAP: /* arithmetic trap */ 278 ucode = fputrap(); 279 if (ucode == -1) 280 goto userout; 281 i = SIGFPE; 282 break; 283 284 case T_PROTFLT: /* general protection fault */ 285 i = SIGBUS; 286 ucode = BUS_OBJERR; 287 break; 288 case T_STKFLT: /* stack fault */ 289 case T_SEGNPFLT: /* segment not present fault */ 290 i = SIGBUS; 291 ucode = BUS_ADRERR; 292 break; 293 case T_TSSFLT: /* invalid TSS fault */ 294 i = SIGBUS; 295 ucode = BUS_OBJERR; 296 break; 297 case T_DOUBLEFLT: /* double fault */ 298 default: 299 i = SIGBUS; 300 ucode = BUS_OBJERR; 301 break; 302 303 case T_PAGEFLT: /* page fault */ 304 addr = frame->tf_addr; 305 #ifdef KSE 306 if (td->td_pflags & TDP_SA) 307 thread_user_enter(td); 308 #endif 309 i = trap_pfault(frame, TRUE); 310 if (i == -1) 311 goto userout; 312 if (i == 0) 313 goto user; 314 315 if (i == SIGSEGV) 316 ucode = SEGV_MAPERR; 317 else { 318 if (prot_fault_translation == 0) { 319 /* 320 * Autodetect. 321 * This check also covers the images 322 * without the ABI-tag ELF note. 323 */ 324 if (p->p_osrel >= 700004) { 325 i = SIGSEGV; 326 ucode = SEGV_ACCERR; 327 } else { 328 i = SIGBUS; 329 ucode = BUS_PAGE_FAULT; 330 } 331 } else if (prot_fault_translation == 1) { 332 /* 333 * Always compat mode. 334 */ 335 i = SIGBUS; 336 ucode = BUS_PAGE_FAULT; 337 } else { 338 /* 339 * Always SIGSEGV mode. 340 */ 341 i = SIGSEGV; 342 ucode = SEGV_ACCERR; 343 } 344 } 345 break; 346 347 case T_DIVIDE: /* integer divide fault */ 348 ucode = FPE_INTDIV; 349 i = SIGFPE; 350 break; 351 352 #ifdef DEV_ISA 353 case T_NMI: 354 /* machine/parity/power fail/"kitchen sink" faults */ 355 /* XXX Giant */ 356 if (isa_nmi(code) == 0) { 357 #ifdef KDB 358 /* 359 * NMI can be hooked up to a pushbutton 360 * for debugging. 361 */ 362 if (kdb_on_nmi) { 363 printf ("NMI ... going to debugger\n"); 364 kdb_trap(type, 0, frame); 365 } 366 #endif /* KDB */ 367 goto userout; 368 } else if (panic_on_nmi) 369 panic("NMI indicates hardware failure"); 370 break; 371 #endif /* DEV_ISA */ 372 373 case T_OFLOW: /* integer overflow fault */ 374 ucode = FPE_INTOVF; 375 i = SIGFPE; 376 break; 377 378 case T_BOUND: /* bounds check fault */ 379 ucode = FPE_FLTSUB; 380 i = SIGFPE; 381 break; 382 383 case T_DNA: 384 /* transparent fault (due to context switch "late") */ 385 if (fpudna()) 386 goto userout; 387 printf("pid %d killed due to lack of floating point\n", 388 p->p_pid); 389 i = SIGKILL; 390 ucode = 0; 391 break; 392 393 case T_FPOPFLT: /* FPU operand fetch fault */ 394 ucode = ILL_COPROC; 395 i = SIGILL; 396 break; 397 398 case T_XMMFLT: /* SIMD floating-point exception */ 399 ucode = 0; /* XXX */ 400 i = SIGFPE; 401 break; 402 } 403 } else { 404 /* kernel trap */ 405 406 KASSERT(cold || td->td_ucred != NULL, 407 ("kernel trap doesn't have ucred")); 408 switch (type) { 409 case T_PAGEFLT: /* page fault */ 410 (void) trap_pfault(frame, FALSE); 411 goto out; 412 413 case T_DNA: 414 /* 415 * The kernel is apparently using fpu for copying. 416 * XXX this should be fatal unless the kernel has 417 * registered such use. 418 */ 419 if (fpudna()) { 420 printf("fpudna in kernel mode!\n"); 421 goto out; 422 } 423 break; 424 425 case T_STKFLT: /* stack fault */ 426 break; 427 428 case T_PROTFLT: /* general protection fault */ 429 case T_SEGNPFLT: /* segment not present fault */ 430 if (td->td_intr_nesting_level != 0) 431 break; 432 433 /* 434 * Invalid segment selectors and out of bounds 435 * %rip's and %rsp's can be set up in user mode. 436 * This causes a fault in kernel mode when the 437 * kernel tries to return to user mode. We want 438 * to get this fault so that we can fix the 439 * problem here and not have to check all the 440 * selectors and pointers when the user changes 441 * them. 442 */ 443 if (frame->tf_rip == (long)doreti_iret) { 444 frame->tf_rip = (long)doreti_iret_fault; 445 goto out; 446 } 447 if (PCPU_GET(curpcb)->pcb_onfault != NULL) { 448 frame->tf_rip = 449 (long)PCPU_GET(curpcb)->pcb_onfault; 450 goto out; 451 } 452 break; 453 454 case T_TSSFLT: 455 /* 456 * PSL_NT can be set in user mode and isn't cleared 457 * automatically when the kernel is entered. This 458 * causes a TSS fault when the kernel attempts to 459 * `iret' because the TSS link is uninitialized. We 460 * want to get this fault so that we can fix the 461 * problem here and not every time the kernel is 462 * entered. 463 */ 464 if (frame->tf_rflags & PSL_NT) { 465 frame->tf_rflags &= ~PSL_NT; 466 goto out; 467 } 468 break; 469 470 case T_TRCTRAP: /* trace trap */ 471 /* 472 * Ignore debug register trace traps due to 473 * accesses in the user's address space, which 474 * can happen under several conditions such as 475 * if a user sets a watchpoint on a buffer and 476 * then passes that buffer to a system call. 477 * We still want to get TRCTRAPS for addresses 478 * in kernel space because that is useful when 479 * debugging the kernel. 480 */ 481 if (user_dbreg_trap()) { 482 /* 483 * Reset breakpoint bits because the 484 * processor doesn't 485 */ 486 /* XXX check upper bits here */ 487 load_dr6(rdr6() & 0xfffffff0); 488 goto out; 489 } 490 /* 491 * FALLTHROUGH (TRCTRAP kernel mode, kernel address) 492 */ 493 case T_BPTFLT: 494 /* 495 * If KDB is enabled, let it handle the debugger trap. 496 * Otherwise, debugger traps "can't happen". 497 */ 498 #ifdef KDB 499 if (kdb_trap(type, 0, frame)) 500 goto out; 501 #endif 502 break; 503 504 #ifdef DEV_ISA 505 case T_NMI: 506 /* XXX Giant */ 507 /* machine/parity/power fail/"kitchen sink" faults */ 508 if (isa_nmi(code) == 0) { 509 #ifdef KDB 510 /* 511 * NMI can be hooked up to a pushbutton 512 * for debugging. 513 */ 514 if (kdb_on_nmi) { 515 printf ("NMI ... going to debugger\n"); 516 kdb_trap(type, 0, frame); 517 } 518 #endif /* KDB */ 519 goto out; 520 } else if (panic_on_nmi == 0) 521 goto out; 522 /* FALLTHROUGH */ 523 #endif /* DEV_ISA */ 524 } 525 526 trap_fatal(frame, 0); 527 goto out; 528 } 529 530 /* Translate fault for emulators (e.g. Linux) */ 531 if (*p->p_sysent->sv_transtrap) 532 i = (*p->p_sysent->sv_transtrap)(i, type); 533 534 ksiginfo_init_trap(&ksi); 535 ksi.ksi_signo = i; 536 ksi.ksi_code = ucode; 537 ksi.ksi_trapno = type; 538 ksi.ksi_addr = (void *)addr; 539 trapsignal(td, &ksi); 540 541 #ifdef DEBUG 542 if (type <= MAX_TRAP_MSG) { 543 uprintf("fatal process exception: %s", 544 trap_msg[type]); 545 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 546 uprintf(", fault VA = 0x%lx", frame->tf_addr); 547 uprintf("\n"); 548 } 549 #endif 550 551 user: 552 userret(td, frame); 553 mtx_assert(&Giant, MA_NOTOWNED); 554 userout: 555 out: 556 return; 557 } 558 559 static int 560 trap_pfault(frame, usermode) 561 struct trapframe *frame; 562 int usermode; 563 { 564 vm_offset_t va; 565 struct vmspace *vm = NULL; 566 vm_map_t map; 567 int rv = 0; 568 vm_prot_t ftype; 569 struct thread *td = curthread; 570 struct proc *p = td->td_proc; 571 vm_offset_t eva = frame->tf_addr; 572 573 va = trunc_page(eva); 574 if (va >= KERNBASE) { 575 /* 576 * Don't allow user-mode faults in kernel address space. 577 */ 578 if (usermode) 579 goto nogo; 580 581 map = kernel_map; 582 } else { 583 /* 584 * This is a fault on non-kernel virtual memory. 585 * vm is initialized above to NULL. If curproc is NULL 586 * or curproc->p_vmspace is NULL the fault is fatal. 587 */ 588 if (p != NULL) 589 vm = p->p_vmspace; 590 591 if (vm == NULL) 592 goto nogo; 593 594 map = &vm->vm_map; 595 } 596 597 /* 598 * PGEX_I is defined only if the execute disable bit capability is 599 * supported and enabled. 600 */ 601 if (frame->tf_err & PGEX_W) 602 ftype = VM_PROT_WRITE; 603 else if ((frame->tf_err & PGEX_I) && pg_nx != 0) 604 ftype = VM_PROT_EXECUTE; 605 else 606 ftype = VM_PROT_READ; 607 608 if (map != kernel_map) { 609 /* 610 * Keep swapout from messing with us during this 611 * critical time. 612 */ 613 PROC_LOCK(p); 614 ++p->p_lock; 615 PROC_UNLOCK(p); 616 617 /* Fault in the user page: */ 618 rv = vm_fault(map, va, ftype, 619 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 620 : VM_FAULT_NORMAL); 621 622 PROC_LOCK(p); 623 --p->p_lock; 624 PROC_UNLOCK(p); 625 } else { 626 /* 627 * Don't have to worry about process locking or stacks in the 628 * kernel. 629 */ 630 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 631 } 632 if (rv == KERN_SUCCESS) 633 return (0); 634 nogo: 635 if (!usermode) { 636 if (td->td_intr_nesting_level == 0 && 637 PCPU_GET(curpcb)->pcb_onfault != NULL) { 638 frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault; 639 return (0); 640 } 641 trap_fatal(frame, eva); 642 return (-1); 643 } 644 645 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 646 } 647 648 static void 649 trap_fatal(frame, eva) 650 struct trapframe *frame; 651 vm_offset_t eva; 652 { 653 int code, ss; 654 u_int type; 655 long esp; 656 struct soft_segment_descriptor softseg; 657 char *msg; 658 659 code = frame->tf_err; 660 type = frame->tf_trapno; 661 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)], &softseg); 662 663 if (type <= MAX_TRAP_MSG) 664 msg = trap_msg[type]; 665 else 666 msg = "UNKNOWN"; 667 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg, 668 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 669 #ifdef SMP 670 /* two separate prints in case of a trap on an unmapped page */ 671 printf("cpuid = %d; ", PCPU_GET(cpuid)); 672 printf("apic id = %02x\n", PCPU_GET(apic_id)); 673 #endif 674 if (type == T_PAGEFLT) { 675 printf("fault virtual address = 0x%lx\n", eva); 676 printf("fault code = %s %s %s, %s\n", 677 code & PGEX_U ? "user" : "supervisor", 678 code & PGEX_W ? "write" : "read", 679 code & PGEX_I ? "instruction" : "data", 680 code & PGEX_P ? "protection violation" : "page not present"); 681 } 682 printf("instruction pointer = 0x%lx:0x%lx\n", 683 frame->tf_cs & 0xffff, frame->tf_rip); 684 if (ISPL(frame->tf_cs) == SEL_UPL) { 685 ss = frame->tf_ss & 0xffff; 686 esp = frame->tf_rsp; 687 } else { 688 ss = GSEL(GDATA_SEL, SEL_KPL); 689 esp = (long)&frame->tf_rsp; 690 } 691 printf("stack pointer = 0x%x:0x%lx\n", ss, esp); 692 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp); 693 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n", 694 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 695 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n", 696 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32, 697 softseg.ssd_gran); 698 printf("processor eflags = "); 699 if (frame->tf_rflags & PSL_T) 700 printf("trace trap, "); 701 if (frame->tf_rflags & PSL_I) 702 printf("interrupt enabled, "); 703 if (frame->tf_rflags & PSL_NT) 704 printf("nested task, "); 705 if (frame->tf_rflags & PSL_RF) 706 printf("resume, "); 707 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12); 708 printf("current process = "); 709 if (curproc) { 710 printf("%lu (%s)\n", 711 (u_long)curproc->p_pid, curproc->p_comm ? 712 curproc->p_comm : ""); 713 } else { 714 printf("Idle\n"); 715 } 716 717 #ifdef KDB 718 if (debugger_on_panic || kdb_active) 719 if (kdb_trap(type, 0, frame)) 720 return; 721 #endif 722 printf("trap number = %d\n", type); 723 if (type <= MAX_TRAP_MSG) 724 panic("%s", trap_msg[type]); 725 else 726 panic("unknown/reserved trap"); 727 } 728 729 /* 730 * Double fault handler. Called when a fault occurs while writing 731 * a frame for a trap/exception onto the stack. This usually occurs 732 * when the stack overflows (such is the case with infinite recursion, 733 * for example). 734 */ 735 void 736 dblfault_handler(struct trapframe *frame) 737 { 738 printf("\nFatal double fault\n"); 739 printf("rip = 0x%lx\n", frame->tf_rip); 740 printf("rsp = 0x%lx\n", frame->tf_rsp); 741 printf("rbp = 0x%lx\n", frame->tf_rbp); 742 #ifdef SMP 743 /* two separate prints in case of a trap on an unmapped page */ 744 printf("cpuid = %d; ", PCPU_GET(cpuid)); 745 printf("apic id = %02x\n", PCPU_GET(apic_id)); 746 #endif 747 panic("double fault"); 748 } 749 750 /* 751 * syscall - system call request C handler 752 * 753 * A system call is essentially treated as a trap. 754 */ 755 void 756 syscall(struct trapframe *frame) 757 { 758 caddr_t params; 759 struct sysent *callp; 760 struct thread *td = curthread; 761 struct proc *p = td->td_proc; 762 register_t orig_tf_rflags; 763 int error; 764 int narg; 765 register_t args[8]; 766 register_t *argp; 767 u_int code; 768 int reg, regcnt; 769 ksiginfo_t ksi; 770 771 PCPU_INC(cnt.v_syscall); 772 773 #ifdef DIAGNOSTIC 774 if (ISPL(frame->tf_cs) != SEL_UPL) { 775 panic("syscall"); 776 /* NOT REACHED */ 777 } 778 #endif 779 780 reg = 0; 781 regcnt = 6; 782 td->td_pticks = 0; 783 td->td_frame = frame; 784 if (td->td_ucred != p->p_ucred) 785 cred_update_thread(td); 786 #ifdef KSE 787 if (p->p_flag & P_SA) 788 thread_user_enter(td); 789 #endif 790 params = (caddr_t)frame->tf_rsp + sizeof(register_t); 791 code = frame->tf_rax; 792 orig_tf_rflags = frame->tf_rflags; 793 794 if (p->p_sysent->sv_prepsyscall) { 795 /* 796 * The prep code is MP aware. 797 */ 798 (*p->p_sysent->sv_prepsyscall)(frame, (int *)args, &code, ¶ms); 799 } else { 800 if (code == SYS_syscall || code == SYS___syscall) { 801 code = frame->tf_rdi; 802 reg++; 803 regcnt--; 804 } 805 } 806 807 if (p->p_sysent->sv_mask) 808 code &= p->p_sysent->sv_mask; 809 810 if (code >= p->p_sysent->sv_size) 811 callp = &p->p_sysent->sv_table[0]; 812 else 813 callp = &p->p_sysent->sv_table[code]; 814 815 narg = callp->sy_narg; 816 817 /* 818 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware 819 */ 820 KASSERT(narg <= sizeof(args) / sizeof(args[0]), 821 ("Too many syscall arguments!")); 822 error = 0; 823 argp = &frame->tf_rdi; 824 argp += reg; 825 bcopy(argp, args, sizeof(args[0]) * regcnt); 826 if (narg > regcnt) { 827 KASSERT(params != NULL, ("copyin args with no params!")); 828 error = copyin(params, &args[regcnt], 829 (narg - regcnt) * sizeof(args[0])); 830 } 831 argp = &args[0]; 832 833 #ifdef KTRACE 834 if (KTRPOINT(td, KTR_SYSCALL)) 835 ktrsyscall(code, narg, argp); 836 #endif 837 838 CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td, 839 td->td_proc->p_pid, td->td_proc->p_comm, code); 840 841 td->td_syscalls++; 842 843 if (error == 0) { 844 td->td_retval[0] = 0; 845 td->td_retval[1] = frame->tf_rdx; 846 847 STOPEVENT(p, S_SCE, narg); 848 849 PTRACESTOP_SC(p, td, S_PT_SCE); 850 851 AUDIT_SYSCALL_ENTER(code, td); 852 error = (*callp->sy_call)(td, argp); 853 AUDIT_SYSCALL_EXIT(error, td); 854 } 855 856 switch (error) { 857 case 0: 858 frame->tf_rax = td->td_retval[0]; 859 frame->tf_rdx = td->td_retval[1]; 860 frame->tf_rflags &= ~PSL_C; 861 break; 862 863 case ERESTART: 864 /* 865 * Reconstruct pc, we know that 'syscall' is 2 bytes. 866 * We have to do a full context restore so that %r10 867 * (which was holding the value of %rcx) is restored for 868 * the next iteration. 869 */ 870 frame->tf_rip -= frame->tf_err; 871 frame->tf_r10 = frame->tf_rcx; 872 td->td_pcb->pcb_flags |= PCB_FULLCTX; 873 break; 874 875 case EJUSTRETURN: 876 break; 877 878 default: 879 if (p->p_sysent->sv_errsize) { 880 if (error >= p->p_sysent->sv_errsize) 881 error = -1; /* XXX */ 882 else 883 error = p->p_sysent->sv_errtbl[error]; 884 } 885 frame->tf_rax = error; 886 frame->tf_rflags |= PSL_C; 887 break; 888 } 889 890 /* 891 * Traced syscall. 892 */ 893 if (orig_tf_rflags & PSL_T) { 894 frame->tf_rflags &= ~PSL_T; 895 ksiginfo_init_trap(&ksi); 896 ksi.ksi_signo = SIGTRAP; 897 ksi.ksi_code = TRAP_TRACE; 898 ksi.ksi_addr = (void *)frame->tf_rip; 899 trapsignal(td, &ksi); 900 } 901 902 /* 903 * Check for misbehavior. 904 */ 905 WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning", 906 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???"); 907 KASSERT(td->td_critnest == 0, 908 ("System call %s returning in a critical section", 909 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???")); 910 KASSERT(td->td_locks == 0, 911 ("System call %s returning with %d locks held", 912 (code >= 0 && code < SYS_MAXSYSCALL) ? syscallnames[code] : "???", 913 td->td_locks)); 914 915 /* 916 * Handle reschedule and other end-of-syscall issues 917 */ 918 userret(td, frame); 919 920 CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td, 921 td->td_proc->p_pid, td->td_proc->p_comm, code); 922 923 #ifdef KTRACE 924 if (KTRPOINT(td, KTR_SYSRET)) 925 ktrsysret(code, error, td->td_retval[0]); 926 #endif 927 928 /* 929 * This works because errno is findable through the 930 * register set. If we ever support an emulation where this 931 * is not the case, this code will need to be revisited. 932 */ 933 STOPEVENT(p, S_SCX, code); 934 935 PTRACESTOP_SC(p, td, S_PT_SCX); 936 }
Cache object: aa78912c590cba279b7337e2e9d0a16a
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