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 1.74 1996/03/27 17:33:39 bde 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 88 int (*pmath_emulate) __P((struct trapframe *)); 89 90 extern void trap __P((struct trapframe frame)); 91 extern int trapwrite __P((unsigned addr)); 92 extern void syscall __P((struct trapframe frame)); 93 94 static int trap_pfault __P((struct trapframe *, int)); 95 static void trap_fatal __P((struct trapframe *)); 96 void dblfault_handler __P((void)); 97 98 extern inthand_t IDTVEC(syscall); 99 100 #define MAX_TRAP_MSG 27 101 static 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 }; 131 132 static void userret __P((struct proc *p, struct trapframe *frame, 133 u_quad_t oticks)); 134 135 static inline void 136 userret(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 */ 188 189 void 190 trap(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 452 453 out: 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 */ 465 static int 466 trap_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 /* Fault in the user page: */ 527 rv = vm_fault(map, va, ftype, FALSE); 528 529 --p->p_lock; 530 } else { 531 /* 532 * Don't allow user-mode faults in kernel address space. 533 */ 534 if (usermode) 535 goto nogo; 536 537 /* 538 * Since we know that kernel virtual address addresses 539 * always have pte pages mapped, we just have to fault 540 * the page. 541 */ 542 rv = vm_fault(kernel_map, va, ftype, FALSE); 543 } 544 545 if (rv == KERN_SUCCESS) 546 return (0); 547 nogo: 548 if (!usermode) { 549 if (curpcb && curpcb->pcb_onfault) { 550 frame->tf_eip = (int)curpcb->pcb_onfault; 551 return (0); 552 } 553 trap_fatal(frame); 554 return (-1); 555 } 556 557 /* kludge to pass faulting virtual address to sendsig */ 558 frame->tf_err = eva; 559 560 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 561 } 562 #endif 563 564 int 565 trap_pfault(frame, usermode) 566 struct trapframe *frame; 567 int usermode; 568 { 569 vm_offset_t va; 570 struct vmspace *vm = NULL; 571 vm_map_t map = 0; 572 int rv = 0; 573 vm_prot_t ftype; 574 int eva; 575 struct proc *p = curproc; 576 577 eva = rcr2(); 578 va = trunc_page((vm_offset_t)eva); 579 580 if (va >= KERNBASE) { 581 /* 582 * Don't allow user-mode faults in kernel address space. 583 */ 584 if (usermode) 585 goto nogo; 586 587 map = kernel_map; 588 } else { 589 /* 590 * This is a fault on non-kernel virtual memory. 591 * vm is initialized above to NULL. If curproc is NULL 592 * or curproc->p_vmspace is NULL the fault is fatal. 593 */ 594 if (p != NULL) 595 vm = p->p_vmspace; 596 597 if (vm == NULL) 598 goto nogo; 599 600 map = &vm->vm_map; 601 } 602 603 if (frame->tf_err & PGEX_W) 604 ftype = VM_PROT_READ | VM_PROT_WRITE; 605 else 606 ftype = VM_PROT_READ; 607 608 if (map != kernel_map) { 609 vm_offset_t v; 610 vm_page_t mpte; 611 612 /* 613 * Keep swapout from messing with us during this 614 * critical time. 615 */ 616 ++p->p_lock; 617 618 /* 619 * Grow the stack if necessary 620 */ 621 if ((caddr_t)va > vm->vm_maxsaddr 622 && (caddr_t)va < (caddr_t)USRSTACK) { 623 if (!grow(p, va)) { 624 rv = KERN_FAILURE; 625 --p->p_lock; 626 goto nogo; 627 } 628 } 629 630 /* Fault in the user page: */ 631 rv = vm_fault(map, va, ftype, FALSE); 632 633 --p->p_lock; 634 } else { 635 /* 636 * Since we know that kernel virtual address addresses 637 * always have pte pages mapped, we just have to fault 638 * the page. 639 */ 640 rv = vm_fault(map, va, ftype, FALSE); 641 } 642 643 if (rv == KERN_SUCCESS) 644 return (0); 645 nogo: 646 if (!usermode) { 647 if (curpcb && curpcb->pcb_onfault) { 648 frame->tf_eip = (int)curpcb->pcb_onfault; 649 return (0); 650 } 651 trap_fatal(frame); 652 return (-1); 653 } 654 655 /* kludge to pass faulting virtual address to sendsig */ 656 frame->tf_err = eva; 657 658 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 659 } 660 661 static void 662 trap_fatal(frame) 663 struct trapframe *frame; 664 { 665 int code, type, eva, ss, esp; 666 struct soft_segment_descriptor softseg; 667 668 code = frame->tf_err; 669 type = frame->tf_trapno; 670 eva = rcr2(); 671 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 672 673 if (type <= MAX_TRAP_MSG) 674 printf("\n\nFatal trap %d: %s while in %s mode\n", 675 type, trap_msg[type], 676 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 677 if (type == T_PAGEFLT) { 678 printf("fault virtual address = 0x%x\n", eva); 679 printf("fault code = %s %s, %s\n", 680 code & PGEX_U ? "user" : "supervisor", 681 code & PGEX_W ? "write" : "read", 682 code & PGEX_P ? "protection violation" : "page not present"); 683 } 684 printf("instruction pointer = 0x%x:0x%x\n", 685 frame->tf_cs & 0xffff, frame->tf_eip); 686 if (ISPL(frame->tf_cs) == SEL_UPL) { 687 ss = frame->tf_ss & 0xffff; 688 esp = frame->tf_esp; 689 } else { 690 ss = GSEL(GDATA_SEL, SEL_KPL); 691 esp = (int)&frame->tf_esp; 692 } 693 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 694 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 695 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 696 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 697 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 698 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 699 softseg.ssd_gran); 700 printf("processor eflags = "); 701 if (frame->tf_eflags & PSL_T) 702 printf("trace trap, "); 703 if (frame->tf_eflags & PSL_I) 704 printf("interrupt enabled, "); 705 if (frame->tf_eflags & PSL_NT) 706 printf("nested task, "); 707 if (frame->tf_eflags & PSL_RF) 708 printf("resume, "); 709 if (frame->tf_eflags & PSL_VM) 710 printf("vm86, "); 711 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 712 printf("current process = "); 713 if (curproc) { 714 printf("%lu (%s)\n", 715 (u_long)curproc->p_pid, curproc->p_comm ? 716 curproc->p_comm : ""); 717 } else { 718 printf("Idle\n"); 719 } 720 printf("interrupt mask = "); 721 if ((cpl & net_imask) == net_imask) 722 printf("net "); 723 if ((cpl & tty_imask) == tty_imask) 724 printf("tty "); 725 if ((cpl & bio_imask) == bio_imask) 726 printf("bio "); 727 if (cpl == 0) 728 printf("none"); 729 printf("\n"); 730 731 #ifdef KDB 732 if (kdb_trap(&psl)) 733 return; 734 #endif 735 #ifdef DDB 736 if (kdb_trap (type, 0, frame)) 737 return; 738 #endif 739 if (type <= MAX_TRAP_MSG) 740 panic(trap_msg[type]); 741 else 742 panic("unknown/reserved trap"); 743 } 744 745 /* 746 * Double fault handler. Called when a fault occurs while writing 747 * a frame for a trap/exception onto the stack. This usually occurs 748 * when the stack overflows (such is the case with infinite recursion, 749 * for example). 750 * 751 * XXX Note that the current PTD gets replaced by IdlePTD when the 752 * task switch occurs. This means that the stack that was active at 753 * the time of the double fault is not available at <kstack> unless 754 * the machine was idle when the double fault occurred. The downside 755 * of this is that "trace <ebp>" in ddb won't work. 756 */ 757 void 758 dblfault_handler() 759 { 760 struct pcb *pcb = curpcb; 761 762 if (pcb != NULL) { 763 printf("\nFatal double fault:\n"); 764 printf("eip = 0x%x\n", pcb->pcb_tss.tss_eip); 765 printf("esp = 0x%x\n", pcb->pcb_tss.tss_esp); 766 printf("ebp = 0x%x\n", pcb->pcb_tss.tss_ebp); 767 } 768 769 panic("double fault"); 770 } 771 772 /* 773 * Compensate for 386 brain damage (missing URKR). 774 * This is a little simpler than the pagefault handler in trap() because 775 * it the page tables have already been faulted in and high addresses 776 * are thrown out early for other reasons. 777 */ 778 int trapwrite(addr) 779 unsigned addr; 780 { 781 struct proc *p; 782 vm_offset_t va, v; 783 struct vmspace *vm; 784 int rv; 785 786 va = trunc_page((vm_offset_t)addr); 787 /* 788 * XXX - MAX is END. Changed > to >= for temp. fix. 789 */ 790 if (va >= VM_MAXUSER_ADDRESS) 791 return (1); 792 793 p = curproc; 794 vm = p->p_vmspace; 795 796 ++p->p_lock; 797 798 if ((caddr_t)va >= vm->vm_maxsaddr 799 && (caddr_t)va < (caddr_t)USRSTACK) { 800 if (!grow(p, va)) { 801 --p->p_lock; 802 return (1); 803 } 804 } 805 806 v = trunc_page(vtopte(va)); 807 808 /* 809 * wire the pte page 810 */ 811 if (va < USRSTACK) { 812 vm_map_pageable(&vm->vm_map, v, round_page(v+1), FALSE); 813 } 814 815 /* 816 * fault the data page 817 */ 818 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, FALSE); 819 820 /* 821 * unwire the pte page 822 */ 823 if (va < USRSTACK) { 824 vm_map_pageable(&vm->vm_map, v, round_page(v+1), TRUE); 825 } 826 827 --p->p_lock; 828 829 if (rv != KERN_SUCCESS) 830 return 1; 831 832 return (0); 833 } 834 835 /* 836 * System call request from POSIX system call gate interface to kernel. 837 * Like trap(), argument is call by reference. 838 */ 839 void 840 syscall(frame) 841 struct trapframe frame; 842 { 843 caddr_t params; 844 int i; 845 struct sysent *callp; 846 struct proc *p = curproc; 847 u_quad_t sticks; 848 int error; 849 int args[8], rval[2]; 850 u_int code; 851 852 sticks = p->p_sticks; 853 if (ISPL(frame.tf_cs) != SEL_UPL) 854 panic("syscall"); 855 856 p->p_md.md_regs = (int *)&frame; 857 params = (caddr_t)frame.tf_esp + sizeof(int); 858 code = frame.tf_eax; 859 if (p->p_sysent->sv_prepsyscall) { 860 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); 861 } else { 862 /* 863 * Need to check if this is a 32 bit or 64 bit syscall. 864 */ 865 if (code == SYS_syscall) { 866 /* 867 * Code is first argument, followed by actual args. 868 */ 869 code = fuword(params); 870 params += sizeof(int); 871 } else if (code == SYS___syscall) { 872 /* 873 * Like syscall, but code is a quad, so as to maintain 874 * quad alignment for the rest of the arguments. 875 */ 876 code = fuword(params); 877 params += sizeof(quad_t); 878 } 879 } 880 881 if (p->p_sysent->sv_mask) 882 code &= p->p_sysent->sv_mask; 883 884 if (code >= p->p_sysent->sv_size) 885 callp = &p->p_sysent->sv_table[0]; 886 else 887 callp = &p->p_sysent->sv_table[code]; 888 889 if (params && (i = callp->sy_narg * sizeof(int)) && 890 (error = copyin(params, (caddr_t)args, (u_int)i))) { 891 #ifdef KTRACE 892 if (KTRPOINT(p, KTR_SYSCALL)) 893 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 894 #endif 895 goto bad; 896 } 897 #ifdef KTRACE 898 if (KTRPOINT(p, KTR_SYSCALL)) 899 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 900 #endif 901 rval[0] = 0; 902 rval[1] = frame.tf_edx; 903 904 error = (*callp->sy_call)(p, args, rval); 905 906 switch (error) { 907 908 case 0: 909 /* 910 * Reinitialize proc pointer `p' as it may be different 911 * if this is a child returning from fork syscall. 912 */ 913 p = curproc; 914 frame.tf_eax = rval[0]; 915 frame.tf_edx = rval[1]; 916 frame.tf_eflags &= ~PSL_C; 917 break; 918 919 case ERESTART: 920 /* 921 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 922 * int 0x80 is 2 bytes. We saved this in tf_err. 923 */ 924 frame.tf_eip -= frame.tf_err; 925 break; 926 927 case EJUSTRETURN: 928 break; 929 930 default: 931 bad: 932 if (p->p_sysent->sv_errsize) 933 if (error >= p->p_sysent->sv_errsize) 934 error = -1; /* XXX */ 935 else 936 error = p->p_sysent->sv_errtbl[error]; 937 frame.tf_eax = error; 938 frame.tf_eflags |= PSL_C; 939 break; 940 } 941 942 if (frame.tf_eflags & PSL_T) { 943 /* Traced syscall. */ 944 frame.tf_eflags &= ~PSL_T; 945 trapsignal(p, SIGTRAP, 0); 946 } 947 948 userret(p, &frame, sticks); 949 950 #ifdef KTRACE 951 if (KTRPOINT(p, KTR_SYSRET)) 952 ktrsysret(p->p_tracep, code, error, rval[0]); 953 #endif 954 } 955