Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/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 * $FreeBSD: src/sys/i386/i386/trap.c,v 1.83.2.11 1999/09/05 08:11:18 peter Exp $ 39 */ 40 41 /* 42 * 386 Trap and System call handling 43 */ 44 45 #include "opt_cpu.h" 46 #include "opt_ddb.h" 47 #include "opt_ktrace.h" 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/proc.h> 52 #include <sys/acct.h> 53 #include <sys/kernel.h> 54 #include <sys/syscall.h> 55 #include <sys/sysent.h> 56 #include <sys/queue.h> 57 #include <sys/vmmeter.h> 58 #ifdef KTRACE 59 #include <sys/ktrace.h> 60 #endif 61 62 #include <vm/vm.h> 63 #include <vm/vm_param.h> 64 #include <vm/vm_prot.h> 65 #include <vm/lock.h> 66 #include <vm/pmap.h> 67 #include <vm/vm_kern.h> 68 #include <vm/vm_map.h> 69 #include <vm/vm_page.h> 70 #include <vm/vm_extern.h> 71 72 #include <sys/user.h> 73 74 #include <machine/cpu.h> 75 #include <machine/md_var.h> 76 #include <machine/psl.h> 77 #include <machine/reg.h> 78 #include <machine/trap.h> 79 #include <machine/../isa/isa_device.h> 80 81 #ifdef POWERFAIL_NMI 82 #include <sys/syslog.h> 83 #include <machine/clock.h> 84 #endif 85 86 #include "isa.h" 87 #include "npx.h" 88 89 int (*pmath_emulate) __P((struct trapframe *)); 90 91 extern void trap __P((struct trapframe frame)); 92 extern int trapwrite __P((unsigned addr)); 93 extern void syscall __P((struct trapframe frame)); 94 95 static int trap_pfault __P((struct trapframe *, int)); 96 static void trap_fatal __P((struct trapframe *)); 97 void dblfault_handler __P((void)); 98 99 extern inthand_t IDTVEC(syscall); 100 101 #define MAX_TRAP_MSG 28 102 static char *trap_msg[] = { 103 "", /* 0 unused */ 104 "privileged instruction fault", /* 1 T_PRIVINFLT */ 105 "", /* 2 unused */ 106 "breakpoint instruction fault", /* 3 T_BPTFLT */ 107 "", /* 4 unused */ 108 "", /* 5 unused */ 109 "arithmetic trap", /* 6 T_ARITHTRAP */ 110 "system forced exception", /* 7 T_ASTFLT */ 111 "", /* 8 unused */ 112 "general protection fault", /* 9 T_PROTFLT */ 113 "trace trap", /* 10 T_TRCTRAP */ 114 "", /* 11 unused */ 115 "page fault", /* 12 T_PAGEFLT */ 116 "", /* 13 unused */ 117 "alignment fault", /* 14 T_ALIGNFLT */ 118 "", /* 15 unused */ 119 "", /* 16 unused */ 120 "", /* 17 unused */ 121 "integer divide fault", /* 18 T_DIVIDE */ 122 "non-maskable interrupt trap", /* 19 T_NMI */ 123 "overflow trap", /* 20 T_OFLOW */ 124 "FPU bounds check fault", /* 21 T_BOUND */ 125 "FPU device not available", /* 22 T_DNA */ 126 "double fault", /* 23 T_DOUBLEFLT */ 127 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 128 "invalid TSS fault", /* 25 T_TSSFLT */ 129 "segment not present fault", /* 26 T_SEGNPFLT */ 130 "stack fault", /* 27 T_STKFLT */ 131 "machine check trap", /* 28 T_MCHK */ 132 }; 133 134 static void userret __P((struct proc *p, struct trapframe *frame, 135 u_quad_t oticks)); 136 137 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 138 extern struct gate_descriptor *t_idt; 139 extern int has_f00f_bug; 140 #endif 141 142 static __inline void 143 userret(p, frame, oticks) 144 struct proc *p; 145 struct trapframe *frame; 146 u_quad_t oticks; 147 { 148 int sig, s; 149 150 while ((sig = CURSIG(p)) != 0) 151 postsig(sig); 152 p->p_priority = p->p_usrpri; 153 if (want_resched) { 154 /* 155 * Since we are curproc, clock will normally just change 156 * our priority without moving us from one queue to another 157 * (since the running process is not on a queue.) 158 * If that happened after we setrunqueue ourselves but before we 159 * mi_switch()'ed, we might not be on the queue indicated by 160 * our priority. 161 */ 162 s = splhigh(); 163 setrunqueue(p); 164 p->p_stats->p_ru.ru_nivcsw++; 165 mi_switch(); 166 splx(s); 167 while ((sig = CURSIG(p)) != 0) 168 postsig(sig); 169 } 170 /* 171 * Charge system time if profiling. 172 */ 173 if (p->p_flag & P_PROFIL) 174 addupc_task(p, frame->tf_eip, 175 (u_int)(p->p_sticks - oticks) * psratio); 176 177 curpriority = p->p_priority; 178 } 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(frame) 189 struct trapframe frame; 190 { 191 struct proc *p = curproc; 192 u_quad_t sticks = 0; 193 int i = 0, ucode = 0, type, code; 194 #ifdef DEBUG 195 u_long eva; 196 #endif 197 198 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 199 restart: 200 #endif 201 type = frame.tf_trapno; 202 code = frame.tf_err; 203 204 if (ISPL(frame.tf_cs) == SEL_UPL) { 205 /* user trap */ 206 207 sticks = p->p_sticks; 208 p->p_md.md_regs = (int *)&frame; 209 210 switch (type) { 211 case T_PRIVINFLT: /* privileged instruction fault */ 212 ucode = type; 213 i = SIGILL; 214 break; 215 216 case T_BPTFLT: /* bpt instruction fault */ 217 case T_TRCTRAP: /* trace trap */ 218 frame.tf_eflags &= ~PSL_T; 219 i = SIGTRAP; 220 break; 221 222 case T_ARITHTRAP: /* arithmetic trap */ 223 ucode = code; 224 i = SIGFPE; 225 break; 226 227 case T_ASTFLT: /* Allow process switch */ 228 astoff(); 229 cnt.v_soft++; 230 if (p->p_flag & P_OWEUPC) { 231 p->p_flag &= ~P_OWEUPC; 232 addupc_task(p, p->p_stats->p_prof.pr_addr, 233 p->p_stats->p_prof.pr_ticks); 234 } 235 goto out; 236 237 case T_PROTFLT: /* general protection fault */ 238 case T_SEGNPFLT: /* segment not present fault */ 239 case T_STKFLT: /* stack fault */ 240 case T_TSSFLT: /* invalid TSS fault */ 241 case T_DOUBLEFLT: /* double fault */ 242 default: 243 ucode = code + BUS_SEGM_FAULT ; 244 i = SIGBUS; 245 break; 246 247 case T_PAGEFLT: /* page fault */ 248 i = trap_pfault(&frame, TRUE); 249 if (i == -1) 250 return; 251 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 252 if (i == -2) 253 goto restart; 254 #endif 255 if (i == 0) 256 goto out; 257 258 ucode = T_PAGEFLT; 259 break; 260 261 case T_DIVIDE: /* integer divide fault */ 262 ucode = FPE_INTDIV_TRAP; 263 i = SIGFPE; 264 break; 265 266 #if NISA > 0 267 case T_NMI: 268 #ifdef POWERFAIL_NMI 269 goto handle_powerfail; 270 #else /* !POWERFAIL_NMI */ 271 #ifdef DDB 272 /* NMI can be hooked up to a pushbutton for debugging */ 273 printf ("NMI ... going to debugger\n"); 274 if (kdb_trap (type, 0, &frame)) 275 return; 276 #endif /* DDB */ 277 /* machine/parity/power fail/"kitchen sink" faults */ 278 if (isa_nmi(code) == 0) return; 279 panic("NMI indicates hardware failure"); 280 #endif /* POWERFAIL_NMI */ 281 #endif /* NISA > 0 */ 282 283 case T_OFLOW: /* integer overflow fault */ 284 ucode = FPE_INTOVF_TRAP; 285 i = SIGFPE; 286 break; 287 288 case T_BOUND: /* bounds check fault */ 289 ucode = FPE_SUBRNG_TRAP; 290 i = SIGFPE; 291 break; 292 293 case T_DNA: 294 #if NNPX > 0 295 /* if a transparent fault (due to context switch "late") */ 296 if (npxdna()) 297 return; 298 #endif 299 if (!pmath_emulate) { 300 i = SIGFPE; 301 ucode = FPE_FPU_NP_TRAP; 302 break; 303 } 304 i = (*pmath_emulate)(&frame); 305 if (i == 0) { 306 if (!(frame.tf_eflags & PSL_T)) 307 return; 308 frame.tf_eflags &= ~PSL_T; 309 i = SIGTRAP; 310 } 311 /* else ucode = emulator_only_knows() XXX */ 312 break; 313 314 case T_FPOPFLT: /* FPU operand fetch fault */ 315 ucode = T_FPOPFLT; 316 i = SIGILL; 317 break; 318 } 319 } else { 320 /* kernel trap */ 321 322 switch (type) { 323 case T_PAGEFLT: /* page fault */ 324 (void) trap_pfault(&frame, FALSE); 325 return; 326 327 case T_DNA: 328 #if NNPX > 0 329 /* 330 * The kernel is apparently using npx for copying. 331 * XXX this should be fatal unless the kernel has 332 * registered such use. 333 */ 334 if (npxdna()) 335 return; 336 #endif 337 break; 338 339 case T_PROTFLT: /* general protection fault */ 340 case T_SEGNPFLT: /* segment not present fault */ 341 /* 342 * Invalid segment selectors and out of bounds 343 * %eip's and %esp's can be set up in user mode. 344 * This causes a fault in kernel mode when the 345 * kernel tries to return to user mode. We want 346 * to get this fault so that we can fix the 347 * problem here and not have to check all the 348 * selectors and pointers when the user changes 349 * them. 350 */ 351 #define MAYBE_DORETI_FAULT(where, whereto) \ 352 do { \ 353 if (frame.tf_eip == (int)where) { \ 354 frame.tf_eip = (int)whereto; \ 355 return; \ 356 } \ 357 } while (0) 358 359 if (intr_nesting_level == 0) { 360 MAYBE_DORETI_FAULT(doreti_iret, 361 doreti_iret_fault); 362 MAYBE_DORETI_FAULT(doreti_popl_ds, 363 doreti_popl_ds_fault); 364 MAYBE_DORETI_FAULT(doreti_popl_es, 365 doreti_popl_es_fault); 366 if (curpcb && curpcb->pcb_onfault) { 367 frame.tf_eip = (int)curpcb->pcb_onfault; 368 return; 369 } 370 } 371 break; 372 373 case T_TSSFLT: 374 /* 375 * PSL_NT can be set in user mode and isn't cleared 376 * automatically when the kernel is entered. This 377 * causes a TSS fault when the kernel attempts to 378 * `iret' because the TSS link is uninitialized. We 379 * want to get this fault so that we can fix the 380 * problem here and not every time the kernel is 381 * entered. 382 */ 383 if (frame.tf_eflags & PSL_NT) { 384 frame.tf_eflags &= ~PSL_NT; 385 return; 386 } 387 break; 388 389 case T_TRCTRAP: /* trace trap */ 390 if (frame.tf_eip == (int)IDTVEC(syscall)) { 391 /* 392 * We've just entered system mode via the 393 * syscall lcall. Continue single stepping 394 * silently until the syscall handler has 395 * saved the flags. 396 */ 397 return; 398 } 399 if (frame.tf_eip == (int)IDTVEC(syscall) + 1) { 400 /* 401 * The syscall handler has now saved the 402 * flags. Stop single stepping it. 403 */ 404 frame.tf_eflags &= ~PSL_T; 405 return; 406 } 407 /* 408 * Fall through. 409 */ 410 case T_BPTFLT: 411 /* 412 * If DDB is enabled, let it handle the debugger trap. 413 * Otherwise, debugger traps "can't happen". 414 */ 415 #ifdef DDB 416 if (kdb_trap (type, 0, &frame)) 417 return; 418 #endif 419 break; 420 421 #if NISA > 0 422 case T_NMI: 423 #ifdef POWERFAIL_NMI 424 #ifndef TIMER_FREQ 425 # define TIMER_FREQ 1193182 426 #endif 427 handle_powerfail: 428 { 429 static unsigned lastalert = 0; 430 431 if(time.tv_sec - lastalert > 10) 432 { 433 log(LOG_WARNING, "NMI: power fail\n"); 434 sysbeep(TIMER_FREQ/880, hz); 435 lastalert = time.tv_sec; 436 } 437 return; 438 } 439 #else /* !POWERFAIL_NMI */ 440 #ifdef DDB 441 /* NMI can be hooked up to a pushbutton for debugging */ 442 printf ("NMI ... going to debugger\n"); 443 if (kdb_trap (type, 0, &frame)) 444 return; 445 #endif /* DDB */ 446 /* machine/parity/power fail/"kitchen sink" faults */ 447 if (isa_nmi(code) == 0) return; 448 /* FALL THROUGH */ 449 #endif /* POWERFAIL_NMI */ 450 #endif /* NISA > 0 */ 451 } 452 453 trap_fatal(&frame); 454 return; 455 } 456 457 /* Translate fault for emulators (e.g. Linux) */ 458 if (*p->p_sysent->sv_transtrap) 459 i = (*p->p_sysent->sv_transtrap)(i, type); 460 461 trapsignal(p, i, ucode); 462 463 #ifdef DEBUG 464 eva = rcr2(); 465 if (type <= MAX_TRAP_MSG) { 466 uprintf("fatal process exception: %s", 467 trap_msg[type]); 468 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 469 uprintf(", fault VA = 0x%x", eva); 470 uprintf("\n"); 471 } 472 #endif 473 474 out: 475 userret(p, &frame, sticks); 476 } 477 478 #ifdef notyet 479 /* 480 * This version doesn't allow a page fault to user space while 481 * in the kernel. The rest of the kernel needs to be made "safe" 482 * before this can be used. I think the only things remaining 483 * to be made safe are the iBCS2 code and the process tracing/ 484 * debugging code. 485 */ 486 static int 487 trap_pfault(frame, usermode) 488 struct trapframe *frame; 489 int usermode; 490 { 491 vm_offset_t va; 492 struct vmspace *vm = NULL; 493 vm_map_t map = 0; 494 int rv = 0; 495 vm_prot_t ftype; 496 int eva; 497 struct proc *p = curproc; 498 499 if (frame->tf_err & PGEX_W) 500 ftype = VM_PROT_READ | VM_PROT_WRITE; 501 else 502 ftype = VM_PROT_READ; 503 504 eva = rcr2(); 505 va = trunc_page((vm_offset_t)eva); 506 507 if (va < VM_MIN_KERNEL_ADDRESS) { 508 vm_offset_t v; 509 vm_page_t mpte; 510 511 if (p == NULL || 512 (!usermode && va < VM_MAXUSER_ADDRESS && 513 (intr_nesting_level != 0 || curpcb == NULL || 514 curpcb->pcb_onfault == NULL))) { 515 trap_fatal(frame); 516 return (-1); 517 } 518 519 /* 520 * This is a fault on non-kernel virtual memory. 521 * vm is initialized above to NULL. If curproc is NULL 522 * or curproc->p_vmspace is NULL the fault is fatal. 523 */ 524 vm = p->p_vmspace; 525 if (vm == NULL) 526 goto nogo; 527 528 map = &vm->vm_map; 529 530 /* 531 * Keep swapout from messing with us during this 532 * critical time. 533 */ 534 ++p->p_lock; 535 536 /* 537 * Grow the stack if necessary 538 */ 539 if ((caddr_t)va > vm->vm_maxsaddr 540 && (caddr_t)va < (caddr_t)USRSTACK) { 541 if (!grow(p, va)) { 542 rv = KERN_FAILURE; 543 --p->p_lock; 544 goto nogo; 545 } 546 } 547 548 /* Fault in the user page: */ 549 rv = vm_fault(map, va, ftype, 550 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 551 552 --p->p_lock; 553 } else { 554 /* 555 * Don't allow user-mode faults in kernel address space. 556 */ 557 if (usermode) 558 goto nogo; 559 560 /* 561 * Since we know that kernel virtual address addresses 562 * always have pte pages mapped, we just have to fault 563 * the page. 564 */ 565 rv = vm_fault(kernel_map, va, ftype, FALSE); 566 } 567 568 if (rv == KERN_SUCCESS) 569 return (0); 570 nogo: 571 if (!usermode) { 572 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 573 frame->tf_eip = (int)curpcb->pcb_onfault; 574 return (0); 575 } 576 trap_fatal(frame); 577 return (-1); 578 } 579 580 /* kludge to pass faulting virtual address to sendsig */ 581 frame->tf_err = eva; 582 583 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 584 } 585 #endif 586 587 int 588 trap_pfault(frame, usermode) 589 struct trapframe *frame; 590 int usermode; 591 { 592 vm_offset_t va; 593 struct vmspace *vm = NULL; 594 vm_map_t map = 0; 595 int rv = 0; 596 vm_prot_t ftype; 597 int eva; 598 struct proc *p = curproc; 599 600 eva = rcr2(); 601 va = trunc_page((vm_offset_t)eva); 602 603 if (va >= KERNBASE) { 604 /* 605 * Don't allow user-mode faults in kernel address space. 606 * An exception: if the faulting address is the invalid 607 * instruction entry in the IDT, then the Intel Pentium 608 * F00F bug workaround was triggered, and we need to 609 * treat it is as an illegal instruction, and not a page 610 * fault. 611 */ 612 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 613 if ((eva == (unsigned int)&t_idt[6]) && has_f00f_bug) { 614 frame->tf_trapno = T_PRIVINFLT; 615 return -2; 616 } 617 #endif 618 if (usermode) 619 goto nogo; 620 621 map = kernel_map; 622 } else { 623 /* 624 * This is a fault on non-kernel virtual memory. 625 * vm is initialized above to NULL. If curproc is NULL 626 * or curproc->p_vmspace is NULL the fault is fatal. 627 */ 628 if (p != NULL) 629 vm = p->p_vmspace; 630 631 if (vm == NULL) 632 goto nogo; 633 634 map = &vm->vm_map; 635 } 636 637 if (frame->tf_err & PGEX_W) 638 ftype = VM_PROT_READ | VM_PROT_WRITE; 639 else 640 ftype = VM_PROT_READ; 641 642 if (map != kernel_map) { 643 /* 644 * Keep swapout from messing with us during this 645 * critical time. 646 */ 647 ++p->p_lock; 648 649 /* 650 * Grow the stack if necessary 651 */ 652 if ((caddr_t)va > vm->vm_maxsaddr 653 && (caddr_t)va < (caddr_t)USRSTACK) { 654 if (!grow(p, va)) { 655 rv = KERN_FAILURE; 656 --p->p_lock; 657 goto nogo; 658 } 659 } 660 661 /* Fault in the user page: */ 662 rv = vm_fault(map, va, ftype, 663 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 664 665 --p->p_lock; 666 } else { 667 /* 668 * Don't have to worry about process locking or stacks in the kernel. 669 */ 670 rv = vm_fault(map, va, ftype, FALSE); 671 } 672 673 if (rv == KERN_SUCCESS) 674 return (0); 675 nogo: 676 if (!usermode) { 677 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 678 frame->tf_eip = (int)curpcb->pcb_onfault; 679 return (0); 680 } 681 trap_fatal(frame); 682 return (-1); 683 } 684 685 /* kludge to pass faulting virtual address to sendsig */ 686 frame->tf_err = eva; 687 688 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 689 } 690 691 static void 692 trap_fatal(frame) 693 struct trapframe *frame; 694 { 695 int code, type, eva, ss, esp; 696 struct soft_segment_descriptor softseg; 697 698 code = frame->tf_err; 699 type = frame->tf_trapno; 700 eva = rcr2(); 701 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 702 703 if (type <= MAX_TRAP_MSG) 704 printf("\n\nFatal trap %d: %s while in %s mode\n", 705 type, trap_msg[type], 706 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 707 if (type == T_PAGEFLT) { 708 printf("fault virtual address = 0x%x\n", eva); 709 printf("fault code = %s %s, %s\n", 710 code & PGEX_U ? "user" : "supervisor", 711 code & PGEX_W ? "write" : "read", 712 code & PGEX_P ? "protection violation" : "page not present"); 713 } 714 printf("instruction pointer = 0x%x:0x%x\n", 715 frame->tf_cs & 0xffff, frame->tf_eip); 716 if (ISPL(frame->tf_cs) == SEL_UPL) { 717 ss = frame->tf_ss & 0xffff; 718 esp = frame->tf_esp; 719 } else { 720 ss = GSEL(GDATA_SEL, SEL_KPL); 721 esp = (int)&frame->tf_esp; 722 } 723 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 724 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 725 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 726 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 727 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 728 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 729 softseg.ssd_gran); 730 printf("processor eflags = "); 731 if (frame->tf_eflags & PSL_T) 732 printf("trace trap, "); 733 if (frame->tf_eflags & PSL_I) 734 printf("interrupt enabled, "); 735 if (frame->tf_eflags & PSL_NT) 736 printf("nested task, "); 737 if (frame->tf_eflags & PSL_RF) 738 printf("resume, "); 739 if (frame->tf_eflags & PSL_VM) 740 printf("vm86, "); 741 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 742 printf("current process = "); 743 if (curproc) { 744 printf("%lu (%s)\n", 745 (u_long)curproc->p_pid, curproc->p_comm ? 746 curproc->p_comm : ""); 747 } else { 748 printf("Idle\n"); 749 } 750 printf("interrupt mask = "); 751 if ((cpl & net_imask) == net_imask) 752 printf("net "); 753 if ((cpl & tty_imask) == tty_imask) 754 printf("tty "); 755 if ((cpl & bio_imask) == bio_imask) 756 printf("bio "); 757 if ((cpl & cam_imask) == cam_imask) 758 printf("cam "); 759 if (cpl == 0) 760 printf("none"); 761 printf("\n"); 762 763 #ifdef KDB 764 if (kdb_trap(&psl)) 765 return; 766 #endif 767 #ifdef DDB 768 if (kdb_trap (type, 0, frame)) 769 return; 770 #endif 771 if (type <= MAX_TRAP_MSG) 772 panic(trap_msg[type]); 773 else 774 panic("unknown/reserved trap"); 775 } 776 777 /* 778 * Double fault handler. Called when a fault occurs while writing 779 * a frame for a trap/exception onto the stack. This usually occurs 780 * when the stack overflows (such is the case with infinite recursion, 781 * for example). 782 * 783 * XXX Note that the current PTD gets replaced by IdlePTD when the 784 * task switch occurs. This means that the stack that was active at 785 * the time of the double fault is not available at <kstack> unless 786 * the machine was idle when the double fault occurred. The downside 787 * of this is that "trace <ebp>" in ddb won't work. 788 */ 789 void 790 dblfault_handler() 791 { 792 struct pcb *pcb = curpcb; 793 794 if (pcb != NULL) { 795 printf("\nFatal double fault:\n"); 796 printf("eip = 0x%x\n", pcb->pcb_tss.tss_eip); 797 printf("esp = 0x%x\n", pcb->pcb_tss.tss_esp); 798 printf("ebp = 0x%x\n", pcb->pcb_tss.tss_ebp); 799 } 800 801 panic("double fault"); 802 } 803 804 /* 805 * Compensate for 386 brain damage (missing URKR). 806 * This is a little simpler than the pagefault handler in trap() because 807 * it the page tables have already been faulted in and high addresses 808 * are thrown out early for other reasons. 809 */ 810 int trapwrite(addr) 811 unsigned addr; 812 { 813 struct proc *p; 814 vm_offset_t va; 815 struct vmspace *vm; 816 int rv; 817 818 va = trunc_page((vm_offset_t)addr); 819 /* 820 * XXX - MAX is END. Changed > to >= for temp. fix. 821 */ 822 if (va >= VM_MAXUSER_ADDRESS) 823 return (1); 824 825 p = curproc; 826 vm = p->p_vmspace; 827 828 ++p->p_lock; 829 830 if ((caddr_t)va >= vm->vm_maxsaddr 831 && (caddr_t)va < (caddr_t)USRSTACK) { 832 if (!grow(p, va)) { 833 --p->p_lock; 834 return (1); 835 } 836 } 837 838 /* 839 * fault the data page 840 */ 841 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, VM_FAULT_DIRTY); 842 843 --p->p_lock; 844 845 if (rv != KERN_SUCCESS) 846 return 1; 847 848 return (0); 849 } 850 851 /* 852 * System call request from POSIX system call gate interface to kernel. 853 * Like trap(), argument is call by reference. 854 */ 855 void 856 syscall(frame) 857 struct trapframe frame; 858 { 859 caddr_t params; 860 int i; 861 struct sysent *callp; 862 struct proc *p = curproc; 863 u_quad_t sticks; 864 int error; 865 int args[8], rval[2]; 866 u_int code; 867 868 sticks = p->p_sticks; 869 if (ISPL(frame.tf_cs) != SEL_UPL) 870 panic("syscall"); 871 872 p->p_md.md_regs = (int *)&frame; 873 params = (caddr_t)frame.tf_esp + sizeof(int); 874 code = frame.tf_eax; 875 if (p->p_sysent->sv_prepsyscall) { 876 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); 877 } else { 878 /* 879 * Need to check if this is a 32 bit or 64 bit syscall. 880 */ 881 if (code == SYS_syscall) { 882 /* 883 * Code is first argument, followed by actual args. 884 */ 885 code = fuword(params); 886 params += sizeof(int); 887 } else if (code == SYS___syscall) { 888 /* 889 * Like syscall, but code is a quad, so as to maintain 890 * quad alignment for the rest of the arguments. 891 */ 892 code = fuword(params); 893 params += sizeof(quad_t); 894 } 895 } 896 897 if (p->p_sysent->sv_mask) 898 code &= p->p_sysent->sv_mask; 899 900 if (code >= p->p_sysent->sv_size) 901 callp = &p->p_sysent->sv_table[0]; 902 else 903 callp = &p->p_sysent->sv_table[code]; 904 905 if (params && (i = callp->sy_narg * sizeof(int)) && 906 (error = copyin(params, (caddr_t)args, (u_int)i))) { 907 #ifdef KTRACE 908 if (KTRPOINT(p, KTR_SYSCALL)) 909 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 910 #endif 911 goto bad; 912 } 913 #ifdef KTRACE 914 if (KTRPOINT(p, KTR_SYSCALL)) 915 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 916 #endif 917 rval[0] = 0; 918 rval[1] = frame.tf_edx; 919 920 error = (*callp->sy_call)(p, args, rval); 921 922 switch (error) { 923 924 case 0: 925 /* 926 * Reinitialize proc pointer `p' as it may be different 927 * if this is a child returning from fork syscall. 928 */ 929 p = curproc; 930 frame.tf_eax = rval[0]; 931 frame.tf_edx = rval[1]; 932 frame.tf_eflags &= ~PSL_C; 933 break; 934 935 case ERESTART: 936 /* 937 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 938 * int 0x80 is 2 bytes. We saved this in tf_err. 939 */ 940 frame.tf_eip -= frame.tf_err; 941 break; 942 943 case EJUSTRETURN: 944 break; 945 946 default: 947 bad: 948 if (p->p_sysent->sv_errsize) 949 if (error >= p->p_sysent->sv_errsize) 950 error = -1; /* XXX */ 951 else 952 error = p->p_sysent->sv_errtbl[error]; 953 frame.tf_eax = error; 954 frame.tf_eflags |= PSL_C; 955 break; 956 } 957 958 if (frame.tf_eflags & PSL_T) { 959 /* Traced syscall. */ 960 frame.tf_eflags &= ~PSL_T; 961 trapsignal(p, SIGTRAP, 0); 962 } 963 964 userret(p, &frame, sticks); 965 966 #ifdef KTRACE 967 if (KTRPOINT(p, KTR_SYSRET)) 968 ktrsysret(p->p_tracep, code, error, rval[0]); 969 #endif 970 }
Cache object: b0a289129967ecc4aa1da17fa17f4190
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