subr_syscall.c revision 14331
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 * $Id: trap.c,v 1.72 1996/02/25 03:02:46 dyson Exp $ 39 */ 40 41/* 42 * 386 Trap and System call handling 43 */ 44 45#include "opt_ktrace.h" 46#include "opt_ddb.h" 47 48#include <sys/param.h> 49#include <sys/systm.h> 50#include <sys/proc.h> 51#include <sys/acct.h> 52#include <sys/kernel.h> 53#include <sys/syscall.h> 54#include <sys/sysent.h> 55#include <sys/queue.h> 56#include <sys/vmmeter.h> 57#ifdef KTRACE 58#include <sys/ktrace.h> 59#endif 60 61#include <vm/vm.h> 62#include <vm/vm_param.h> 63#include <vm/vm_prot.h> 64#include <vm/lock.h> 65#include <vm/pmap.h> 66#include <vm/vm_kern.h> 67#include <vm/vm_map.h> 68#include <vm/vm_page.h> 69#include <vm/vm_extern.h> 70 71#include <sys/user.h> 72 73#include <machine/cpu.h> 74#include <machine/md_var.h> 75#include <machine/psl.h> 76#include <machine/reg.h> 77#include <machine/trap.h> 78#include <machine/../isa/isa_device.h> 79 80#ifdef POWERFAIL_NMI 81# include <syslog.h> 82# include <machine/clock.h> 83#endif 84 85#include "isa.h" 86#include "npx.h" 87 88int (*pmath_emulate) __P((struct trapframe *)); 89 90extern void trap __P((struct trapframe frame)); 91extern int trapwrite __P((unsigned addr)); 92extern void syscall __P((struct trapframe frame)); 93 94static int trap_pfault __P((struct trapframe *, int)); 95static void trap_fatal __P((struct trapframe *)); 96void dblfault_handler __P((void)); 97 98extern inthand_t IDTVEC(syscall); 99 100#define MAX_TRAP_MSG 27 101static char *trap_msg[] = { 102 "", /* 0 unused */ 103 "privileged instruction fault", /* 1 T_PRIVINFLT */ 104 "", /* 2 unused */ 105 "breakpoint instruction fault", /* 3 T_BPTFLT */ 106 "", /* 4 unused */ 107 "", /* 5 unused */ 108 "arithmetic trap", /* 6 T_ARITHTRAP */ 109 "system forced exception", /* 7 T_ASTFLT */ 110 "", /* 8 unused */ 111 "general protection fault", /* 9 T_PROTFLT */ 112 "trace trap", /* 10 T_TRCTRAP */ 113 "", /* 11 unused */ 114 "page fault", /* 12 T_PAGEFLT */ 115 "", /* 13 unused */ 116 "alignment fault", /* 14 T_ALIGNFLT */ 117 "", /* 15 unused */ 118 "", /* 16 unused */ 119 "", /* 17 unused */ 120 "integer divide fault", /* 18 T_DIVIDE */ 121 "non-maskable interrupt trap", /* 19 T_NMI */ 122 "overflow trap", /* 20 T_OFLOW */ 123 "FPU bounds check fault", /* 21 T_BOUND */ 124 "FPU device not available", /* 22 T_DNA */ 125 "double fault", /* 23 T_DOUBLEFLT */ 126 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 127 "invalid TSS fault", /* 25 T_TSSFLT */ 128 "segment not present fault", /* 26 T_SEGNPFLT */ 129 "stack fault", /* 27 T_STKFLT */ 130}; 131 132static void userret __P((struct proc *p, struct trapframe *frame, 133 u_quad_t oticks)); 134 135static inline void 136userret(p, frame, oticks) 137 struct proc *p; 138 struct trapframe *frame; 139 u_quad_t oticks; 140{ 141 int sig, s; 142 143 while ((sig = CURSIG(p)) != 0) 144 postsig(sig); 145 p->p_priority = p->p_usrpri; 146 if (want_resched) { 147 /* 148 * Since we are curproc, clock will normally just change 149 * our priority without moving us from one queue to another 150 * (since the running process is not on a queue.) 151 * If that happened after we setrunqueue ourselves but before we 152 * mi_switch()'ed, we might not be on the queue indicated by 153 * our priority. 154 */ 155 s = splclock(); 156 setrunqueue(p); 157 p->p_stats->p_ru.ru_nivcsw++; 158 mi_switch(); 159 splx(s); 160 while ((sig = CURSIG(p)) != 0) 161 postsig(sig); 162 } 163 /* 164 * Charge system time if profiling. 165 */ 166 if (p->p_flag & P_PROFIL) { 167 u_quad_t ticks = p->p_sticks - oticks; 168 169 if (ticks) { 170#ifdef PROFTIMER 171 extern int profscale; 172 addupc(frame->tf_eip, &p->p_stats->p_prof, 173 ticks * profscale); 174#else 175 addupc(frame->tf_eip, &p->p_stats->p_prof, ticks); 176#endif 177 } 178 } 179 curpriority = p->p_priority; 180} 181 182/* 183 * Exception, fault, and trap interface to the FreeBSD kernel. 184 * This common code is called from assembly language IDT gate entry 185 * routines that prepare a suitable stack frame, and restore this 186 * frame after the exception has been processed. 187 */ 188 189void 190trap(frame) 191 struct trapframe frame; 192{ 193 struct proc *p = curproc; 194 u_quad_t sticks = 0; 195 int i = 0, ucode = 0, type, code; 196#ifdef DEBUG 197 u_long eva; 198#endif 199 200 type = frame.tf_trapno; 201 code = frame.tf_err; 202 203 if (ISPL(frame.tf_cs) == SEL_UPL) { 204 /* user trap */ 205 206 sticks = p->p_sticks; 207 p->p_md.md_regs = (int *)&frame; 208 209 switch (type) { 210 case T_PRIVINFLT: /* privileged instruction fault */ 211 ucode = type; 212 i = SIGILL; 213 break; 214 215 case T_BPTFLT: /* bpt instruction fault */ 216 case T_TRCTRAP: /* trace trap */ 217 frame.tf_eflags &= ~PSL_T; 218 i = SIGTRAP; 219 break; 220 221 case T_ARITHTRAP: /* arithmetic trap */ 222 ucode = code; 223 i = SIGFPE; 224 break; 225 226 case T_ASTFLT: /* Allow process switch */ 227 astoff(); 228 cnt.v_soft++; 229 if (p->p_flag & P_OWEUPC) { 230 addupc(frame.tf_eip, &p->p_stats->p_prof, 1); 231 p->p_flag &= ~P_OWEUPC; 232 } 233 goto out; 234 235 case T_PROTFLT: /* general protection fault */ 236 case T_SEGNPFLT: /* segment not present fault */ 237 case T_STKFLT: /* stack fault */ 238 case T_TSSFLT: /* invalid TSS fault */ 239 case T_DOUBLEFLT: /* double fault */ 240 default: 241 ucode = code + BUS_SEGM_FAULT ; 242 i = SIGBUS; 243 break; 244 245 case T_PAGEFLT: /* page fault */ 246 i = trap_pfault(&frame, TRUE); 247 if (i == -1) 248 return; 249 if (i == 0) 250 goto out; 251 252 ucode = T_PAGEFLT; 253 break; 254 255 case T_DIVIDE: /* integer divide fault */ 256 ucode = FPE_INTDIV_TRAP; 257 i = SIGFPE; 258 break; 259 260#if NISA > 0 261 case T_NMI: 262#ifdef POWERFAIL_NMI 263 goto handle_powerfail; 264#else /* !POWERFAIL_NMI */ 265#ifdef DDB 266 /* NMI can be hooked up to a pushbutton for debugging */ 267 printf ("NMI ... going to debugger\n"); 268 if (kdb_trap (type, 0, &frame)) 269 return; 270#endif /* DDB */ 271 /* machine/parity/power fail/"kitchen sink" faults */ 272 if (isa_nmi(code) == 0) return; 273 panic("NMI indicates hardware failure"); 274#endif /* POWERFAIL_NMI */ 275#endif /* NISA > 0 */ 276 277 case T_OFLOW: /* integer overflow fault */ 278 ucode = FPE_INTOVF_TRAP; 279 i = SIGFPE; 280 break; 281 282 case T_BOUND: /* bounds check fault */ 283 ucode = FPE_SUBRNG_TRAP; 284 i = SIGFPE; 285 break; 286 287 case T_DNA: 288#if NNPX > 0 289 /* if a transparent fault (due to context switch "late") */ 290 if (npxdna()) 291 return; 292#endif /* NNPX > 0 */ 293 294 if (!pmath_emulate) { 295 i = SIGFPE; 296 ucode = FPE_FPU_NP_TRAP; 297 break; 298 } 299 i = (*pmath_emulate)(&frame); 300 if (i == 0) { 301 if (!(frame.tf_eflags & PSL_T)) 302 return; 303 frame.tf_eflags &= ~PSL_T; 304 i = SIGTRAP; 305 } 306 /* else ucode = emulator_only_knows() XXX */ 307 break; 308 309 case T_FPOPFLT: /* FPU operand fetch fault */ 310 ucode = T_FPOPFLT; 311 i = SIGILL; 312 break; 313 } 314 } else { 315 /* kernel trap */ 316 317 switch (type) { 318 case T_PAGEFLT: /* page fault */ 319 (void) trap_pfault(&frame, FALSE); 320 return; 321 322 case T_PROTFLT: /* general protection fault */ 323 case T_SEGNPFLT: /* segment not present fault */ 324 /* 325 * Invalid segment selectors and out of bounds 326 * %eip's and %esp's can be set up in user mode. 327 * This causes a fault in kernel mode when the 328 * kernel tries to return to user mode. We want 329 * to get this fault so that we can fix the 330 * problem here and not have to check all the 331 * selectors and pointers when the user changes 332 * them. 333 */ 334#define MAYBE_DORETI_FAULT(where, whereto) \ 335 do { \ 336 if (frame.tf_eip == (int)where) { \ 337 frame.tf_eip = (int)whereto; \ 338 return; \ 339 } \ 340 } while (0) 341 342 if (intr_nesting_level == 0) { 343 MAYBE_DORETI_FAULT(doreti_iret, 344 doreti_iret_fault); 345 MAYBE_DORETI_FAULT(doreti_popl_ds, 346 doreti_popl_ds_fault); 347 MAYBE_DORETI_FAULT(doreti_popl_es, 348 doreti_popl_es_fault); 349 } 350 if (curpcb && curpcb->pcb_onfault) { 351 frame.tf_eip = (int)curpcb->pcb_onfault; 352 return; 353 } 354 break; 355 356 case T_TSSFLT: 357 /* 358 * PSL_NT can be set in user mode and isn't cleared 359 * automatically when the kernel is entered. This 360 * causes a TSS fault when the kernel attempts to 361 * `iret' because the TSS link is uninitialized. We 362 * want to get this fault so that we can fix the 363 * problem here and not every time the kernel is 364 * entered. 365 */ 366 if (frame.tf_eflags & PSL_NT) { 367 frame.tf_eflags &= ~PSL_NT; 368 return; 369 } 370 break; 371 372 case T_TRCTRAP: /* trace trap */ 373 if (frame.tf_eip == (int)IDTVEC(syscall)) { 374 /* 375 * We've just entered system mode via the 376 * syscall lcall. Continue single stepping 377 * silently until the syscall handler has 378 * saved the flags. 379 */ 380 return; 381 } 382 if (frame.tf_eip == (int)IDTVEC(syscall) + 1) { 383 /* 384 * The syscall handler has now saved the 385 * flags. Stop single stepping it. 386 */ 387 frame.tf_eflags &= ~PSL_T; 388 return; 389 } 390 /* 391 * Fall through. 392 */ 393 case T_BPTFLT: 394 /* 395 * If DDB is enabled, let it handle the debugger trap. 396 * Otherwise, debugger traps "can't happen". 397 */ 398#ifdef DDB 399 if (kdb_trap (type, 0, &frame)) 400 return; 401#endif 402 break; 403 404#if NISA > 0 405 case T_NMI: 406#ifdef POWERFAIL_NMI 407#ifndef TIMER_FREQ 408# define TIMER_FREQ 1193182 409#endif 410 handle_powerfail: 411 { 412 static unsigned lastalert = 0; 413 414 if(time.tv_sec - lastalert > 10) 415 { 416 log(LOG_WARNING, "NMI: power fail\n"); 417 sysbeep(TIMER_FREQ/880, hz); 418 lastalert = time.tv_sec; 419 } 420 return; 421 } 422#else /* !POWERFAIL_NMI */ 423#ifdef DDB 424 /* NMI can be hooked up to a pushbutton for debugging */ 425 printf ("NMI ... going to debugger\n"); 426 if (kdb_trap (type, 0, &frame)) 427 return; 428#endif /* DDB */ 429 /* machine/parity/power fail/"kitchen sink" faults */ 430 if (isa_nmi(code) == 0) return; 431 /* FALL THROUGH */ 432#endif /* POWERFAIL_NMI */ 433#endif /* NISA > 0 */ 434 } 435 436 trap_fatal(&frame); 437 return; 438 } 439 440 trapsignal(p, i, ucode); 441 442#ifdef DEBUG 443 eva = rcr2(); 444 if (type <= MAX_TRAP_MSG) { 445 uprintf("fatal process exception: %s", 446 trap_msg[type]); 447 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 448 uprintf(", fault VA = 0x%x", eva); 449 uprintf("\n"); 450 } 451#endif 452 453out: 454 userret(p, &frame, sticks); 455} 456 457#ifdef notyet 458/* 459 * This version doesn't allow a page fault to user space while 460 * in the kernel. The rest of the kernel needs to be made "safe" 461 * before this can be used. I think the only things remaining 462 * to be made safe are the iBCS2 code and the process tracing/ 463 * debugging code. 464 */ 465static int 466trap_pfault(frame, usermode) 467 struct trapframe *frame; 468 int usermode; 469{ 470 vm_offset_t va; 471 struct vmspace *vm = NULL; 472 vm_map_t map = 0; 473 int rv = 0; 474 vm_prot_t ftype; 475 int eva; 476 struct proc *p = curproc; 477 478 if (frame->tf_err & PGEX_W) 479 ftype = VM_PROT_READ | VM_PROT_WRITE; 480 else 481 ftype = VM_PROT_READ; 482 483 eva = rcr2(); 484 va = trunc_page((vm_offset_t)eva); 485 486 if (va < VM_MIN_KERNEL_ADDRESS) { 487 vm_offset_t v; 488 vm_page_t mpte; 489 490 if (p == NULL || 491 (!usermode && va < VM_MAXUSER_ADDRESS && 492 (curpcb == NULL || curpcb->pcb_onfault == NULL))) { 493 trap_fatal(frame); 494 return (-1); 495 } 496 497 /* 498 * This is a fault on non-kernel virtual memory. 499 * vm is initialized above to NULL. If curproc is NULL 500 * or curproc->p_vmspace is NULL the fault is fatal. 501 */ 502 vm = p->p_vmspace; 503 if (vm == NULL) 504 goto nogo; 505 506 map = &vm->vm_map; 507 508 /* 509 * Keep swapout from messing with us during this 510 * critical time. 511 */ 512 ++p->p_lock; 513 514 /* 515 * Grow the stack if necessary 516 */ 517 if ((caddr_t)va > vm->vm_maxsaddr 518 && (caddr_t)va < (caddr_t)USRSTACK) { 519 if (!grow(p, va)) { 520 rv = KERN_FAILURE; 521 --p->p_lock; 522 goto nogo; 523 } 524 } 525 526 /* 527 * Check if page table is mapped, if not, 528 * fault it first 529 */ 530 v = (vm_offset_t) vtopte(va); 531 532 /* Fault the pte only if needed: */ 533 if (*((int *)vtopte(v)) == 0) 534 (void) vm_fault(map, trunc_page(v), VM_PROT_WRITE, FALSE); 535 536 mpte = pmap_use_pt( vm_map_pmap(map), va); 537 538 /* Fault in the user page: */ 539 rv = vm_fault(map, va, ftype, FALSE); 540 541 pmap_unuse_pt( vm_map_pmap(map), va, mpte); 542 543 --p->p_lock; 544 } else { 545 /* 546 * Don't allow user-mode faults in kernel address space. 547 */ 548 if (usermode) 549 goto nogo; 550 551 /* 552 * Since we know that kernel virtual address addresses 553 * always have pte pages mapped, we just have to fault 554 * the page. 555 */ 556 rv = vm_fault(kernel_map, va, ftype, FALSE); 557 } 558 559 if (rv == KERN_SUCCESS) 560 return (0); 561nogo: 562 if (!usermode) { 563 if (curpcb && curpcb->pcb_onfault) { 564 frame->tf_eip = (int)curpcb->pcb_onfault; 565 return (0); 566 } 567 trap_fatal(frame); 568 return (-1); 569 } 570 571 /* kludge to pass faulting virtual address to sendsig */ 572 frame->tf_err = eva; 573 574 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 575} 576#endif 577 578int 579trap_pfault(frame, usermode) 580 struct trapframe *frame; 581 int usermode; 582{ 583 vm_offset_t va; 584 struct vmspace *vm = NULL; 585 vm_map_t map = 0; 586 int rv = 0; 587 vm_prot_t ftype; 588 int eva; 589 struct proc *p = curproc; 590 591 eva = rcr2(); 592 va = trunc_page((vm_offset_t)eva); 593 594 if (va >= KERNBASE) { 595 /* 596 * Don't allow user-mode faults in kernel address space. 597 */ 598 if (usermode) 599 goto nogo; 600 601 map = kernel_map; 602 } else { 603 /* 604 * This is a fault on non-kernel virtual memory. 605 * vm is initialized above to NULL. If curproc is NULL 606 * or curproc->p_vmspace is NULL the fault is fatal. 607 */ 608 if (p != NULL) 609 vm = p->p_vmspace; 610 611 if (vm == NULL) 612 goto nogo; 613 614 map = &vm->vm_map; 615 } 616 617 if (frame->tf_err & PGEX_W) 618 ftype = VM_PROT_READ | VM_PROT_WRITE; 619 else 620 ftype = VM_PROT_READ; 621 622 if (map != kernel_map) { 623 vm_offset_t v; 624 vm_page_t mpte; 625 626 /* 627 * Keep swapout from messing with us during this 628 * critical time. 629 */ 630 ++p->p_lock; 631 632 /* 633 * Grow the stack if necessary 634 */ 635 if ((caddr_t)va > vm->vm_maxsaddr 636 && (caddr_t)va < (caddr_t)USRSTACK) { 637 if (!grow(p, va)) { 638 rv = KERN_FAILURE; 639 --p->p_lock; 640 goto nogo; 641 } 642 } 643 644 /* 645 * Check if page table is mapped, if not, 646 * fault it first 647 */ 648 v = (vm_offset_t) vtopte(va); 649 650 /* Fault the pte only if needed: */ 651 if (*((int *)vtopte(v)) == 0) 652 (void) vm_fault(map, 653 trunc_page(v), VM_PROT_WRITE, FALSE); 654 655 mpte = pmap_use_pt( vm_map_pmap(map), va); 656 657 /* Fault in the user page: */ 658 rv = vm_fault(map, va, ftype, FALSE); 659 660 pmap_unuse_pt( vm_map_pmap(map), va, mpte); 661 662 --p->p_lock; 663 } else { 664 /* 665 * Since we know that kernel virtual address addresses 666 * always have pte pages mapped, we just have to fault 667 * the page. 668 */ 669 rv = vm_fault(map, va, ftype, FALSE); 670 } 671 672 if (rv == KERN_SUCCESS) 673 return (0); 674nogo: 675 if (!usermode) { 676 if (curpcb && curpcb->pcb_onfault) { 677 frame->tf_eip = (int)curpcb->pcb_onfault; 678 return (0); 679 } 680 trap_fatal(frame); 681 return (-1); 682 } 683 684 /* kludge to pass faulting virtual address to sendsig */ 685 frame->tf_err = eva; 686 687 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 688} 689 690static void 691trap_fatal(frame) 692 struct trapframe *frame; 693{ 694 int code, type, eva; 695 struct soft_segment_descriptor softseg; 696 697 code = frame->tf_err; 698 type = frame->tf_trapno; 699 eva = rcr2(); 700 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 701 702 if (type <= MAX_TRAP_MSG) 703 printf("\n\nFatal trap %d: %s while in %s mode\n", 704 type, trap_msg[type], 705 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 706 if (type == T_PAGEFLT) { 707 printf("fault virtual address = 0x%x\n", eva); 708 printf("fault code = %s %s, %s\n", 709 code & PGEX_U ? "user" : "supervisor", 710 code & PGEX_W ? "write" : "read", 711 code & PGEX_P ? "protection violation" : "page not present"); 712 } 713 printf("instruction pointer = 0x%x:0x%x\n", frame->tf_cs & 0xffff, frame->tf_eip); 714 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 715 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 716 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 717 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, softseg.ssd_gran); 718 printf("processor eflags = "); 719 if (frame->tf_eflags & PSL_T) 720 printf("trace/trap, "); 721 if (frame->tf_eflags & PSL_I) 722 printf("interrupt enabled, "); 723 if (frame->tf_eflags & PSL_NT) 724 printf("nested task, "); 725 if (frame->tf_eflags & PSL_RF) 726 printf("resume, "); 727 if (frame->tf_eflags & PSL_VM) 728 printf("vm86, "); 729 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 730 printf("current process = "); 731 if (curproc) { 732 printf("%lu (%s)\n", 733 (u_long)curproc->p_pid, curproc->p_comm ? 734 curproc->p_comm : ""); 735 } else { 736 printf("Idle\n"); 737 } 738 printf("interrupt mask = "); 739 if ((cpl & net_imask) == net_imask) 740 printf("net "); 741 if ((cpl & tty_imask) == tty_imask) 742 printf("tty "); 743 if ((cpl & bio_imask) == bio_imask) 744 printf("bio "); 745 if (cpl == 0) 746 printf("none"); 747 printf("\n"); 748 749#ifdef KDB 750 if (kdb_trap(&psl)) 751 return; 752#endif 753#ifdef DDB 754 if (kdb_trap (type, 0, frame)) 755 return; 756#endif 757 if (type <= MAX_TRAP_MSG) 758 panic(trap_msg[type]); 759 else 760 panic("unknown/reserved trap"); 761} 762 763/* 764 * Double fault handler. Called when a fault occurs while writing 765 * a frame for a trap/exception onto the stack. This usually occurs 766 * when the stack overflows (such is the case with infinite recursion, 767 * for example). 768 * 769 * XXX Note that the current PTD gets replaced by IdlePTD when the 770 * task switch occurs. This means that the stack that was active at 771 * the time of the double fault is not available at <kstack> unless 772 * the machine was idle when the double fault occurred. The downside 773 * of this is that "trace <ebp>" in ddb won't work. 774 */ 775void 776dblfault_handler() 777{ 778 struct pcb *pcb = curpcb; 779 780 if (pcb != NULL) { 781 printf("\nFatal double fault:\n"); 782 printf("eip = 0x%x\n", pcb->pcb_tss.tss_eip); 783 printf("esp = 0x%x\n", pcb->pcb_tss.tss_esp); 784 printf("ebp = 0x%x\n", pcb->pcb_tss.tss_ebp); 785 } 786 787 panic("double fault"); 788} 789 790/* 791 * Compensate for 386 brain damage (missing URKR). 792 * This is a little simpler than the pagefault handler in trap() because 793 * it the page tables have already been faulted in and high addresses 794 * are thrown out early for other reasons. 795 */ 796int trapwrite(addr) 797 unsigned addr; 798{ 799 struct proc *p; 800 vm_offset_t va, v; 801 struct vmspace *vm; 802 int rv; 803 804 va = trunc_page((vm_offset_t)addr); 805 /* 806 * XXX - MAX is END. Changed > to >= for temp. fix. 807 */ 808 if (va >= VM_MAXUSER_ADDRESS) 809 return (1); 810 811 p = curproc; 812 vm = p->p_vmspace; 813 814 ++p->p_lock; 815 816 if ((caddr_t)va >= vm->vm_maxsaddr 817 && (caddr_t)va < (caddr_t)USRSTACK) { 818 if (!grow(p, va)) { 819 --p->p_lock; 820 return (1); 821 } 822 } 823 824 v = trunc_page(vtopte(va)); 825 826 /* 827 * wire the pte page 828 */ 829 if (va < USRSTACK) { 830 vm_map_pageable(&vm->vm_map, v, round_page(v+1), FALSE); 831 } 832 833 /* 834 * fault the data page 835 */ 836 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, FALSE); 837 838 /* 839 * unwire the pte page 840 */ 841 if (va < USRSTACK) { 842 vm_map_pageable(&vm->vm_map, v, round_page(v+1), TRUE); 843 } 844 845 --p->p_lock; 846 847 if (rv != KERN_SUCCESS) 848 return 1; 849 850 return (0); 851} 852 853/* 854 * System call request from POSIX system call gate interface to kernel. 855 * Like trap(), argument is call by reference. 856 */ 857void 858syscall(frame) 859 struct trapframe frame; 860{ 861 caddr_t params; 862 int i; 863 struct sysent *callp; 864 struct proc *p = curproc; 865 u_quad_t sticks; 866 int error; 867 int args[8], rval[2]; 868 u_int code; 869 870 sticks = p->p_sticks; 871 if (ISPL(frame.tf_cs) != SEL_UPL) 872 panic("syscall"); 873 874 p->p_md.md_regs = (int *)&frame; 875 params = (caddr_t)frame.tf_esp + sizeof(int); 876 code = frame.tf_eax; 877 if (p->p_sysent->sv_prepsyscall) { 878 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); 879 } else { 880 /* 881 * Need to check if this is a 32 bit or 64 bit syscall. 882 */ 883 if (code == SYS_syscall) { 884 /* 885 * Code is first argument, followed by actual args. 886 */ 887 code = fuword(params); 888 params += sizeof(int); 889 } else if (code == SYS___syscall) { 890 /* 891 * Like syscall, but code is a quad, so as to maintain 892 * quad alignment for the rest of the arguments. 893 */ 894 code = fuword(params); 895 params += sizeof(quad_t); 896 } 897 } 898 899 if (p->p_sysent->sv_mask) 900 code &= p->p_sysent->sv_mask; 901 902 if (code >= p->p_sysent->sv_size) 903 callp = &p->p_sysent->sv_table[0]; 904 else 905 callp = &p->p_sysent->sv_table[code]; 906 907 if (params && (i = callp->sy_narg * sizeof(int)) && 908 (error = copyin(params, (caddr_t)args, (u_int)i))) { 909#ifdef KTRACE 910 if (KTRPOINT(p, KTR_SYSCALL)) 911 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 912#endif 913 goto bad; 914 } 915#ifdef KTRACE 916 if (KTRPOINT(p, KTR_SYSCALL)) 917 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 918#endif 919 rval[0] = 0; 920 rval[1] = frame.tf_edx; 921 922 error = (*callp->sy_call)(p, args, rval); 923 924 switch (error) { 925 926 case 0: 927 /* 928 * Reinitialize proc pointer `p' as it may be different 929 * if this is a child returning from fork syscall. 930 */ 931 p = curproc; 932 frame.tf_eax = rval[0]; 933 frame.tf_edx = rval[1]; 934 frame.tf_eflags &= ~PSL_C; 935 break; 936 937 case ERESTART: 938 /* 939 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 940 * int 0x80 is 2 bytes. We saved this in tf_err. 941 */ 942 frame.tf_eip -= frame.tf_err; 943 break; 944 945 case EJUSTRETURN: 946 break; 947 948 default: 949bad: 950 if (p->p_sysent->sv_errsize) 951 if (error >= p->p_sysent->sv_errsize) 952 error = -1; /* XXX */ 953 else 954 error = p->p_sysent->sv_errtbl[error]; 955 frame.tf_eax = error; 956 frame.tf_eflags |= PSL_C; 957 break; 958 } 959 960 if (frame.tf_eflags & PSL_T) { 961 /* Traced syscall. */ 962 frame.tf_eflags &= ~PSL_T; 963 trapsignal(p, SIGTRAP, 0); 964 } 965 966 userret(p, &frame, sticks); 967 968#ifdef KTRACE 969 if (KTRPOINT(p, KTR_SYSRET)) 970 ktrsysret(p->p_tracep, code, error, rval[0]); 971#endif 972} 973