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 1.127 1998/04/28 18:15:04 eivind 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 #include "opt_trap.h" 49 #include "opt_vm86.h" 50 51 #include <sys/param.h> 52 #include <sys/systm.h> 53 #include <sys/proc.h> 54 #include <sys/pioctl.h> 55 #include <sys/kernel.h> 56 #include <sys/resourcevar.h> 57 #include <sys/signalvar.h> 58 #include <sys/syscall.h> 59 #include <sys/sysent.h> 60 #include <sys/uio.h> 61 #include <sys/vmmeter.h> 62 #ifdef KTRACE 63 #include <sys/ktrace.h> 64 #endif 65 66 #include <vm/vm.h> 67 #include <vm/vm_param.h> 68 #include <vm/vm_prot.h> 69 #include <sys/lock.h> 70 #include <vm/pmap.h> 71 #include <vm/vm_kern.h> 72 #include <vm/vm_map.h> 73 #include <vm/vm_page.h> 74 #include <vm/vm_extern.h> 75 76 #include <machine/cpu.h> 77 #include <machine/ipl.h> 78 #include <machine/md_var.h> 79 #include <machine/pcb.h> 80 #ifdef SMP 81 #include <machine/smp.h> 82 #endif 83 #include <machine/tss.h> 84 85 #include <i386/isa/intr_machdep.h> 86 87 #ifdef POWERFAIL_NMI 88 #include <sys/syslog.h> 89 #include <machine/clock.h> 90 #endif 91 92 #ifdef VM86 93 #include <machine/vm86.h> 94 #endif 95 96 #include "isa.h" 97 #include "npx.h" 98 99 extern struct i386tss common_tss; 100 101 int (*pmath_emulate) __P((struct trapframe *)); 102 103 extern void trap __P((struct trapframe frame)); 104 extern int trapwrite __P((unsigned addr)); 105 extern void syscall __P((struct trapframe frame)); 106 107 static int trap_pfault __P((struct trapframe *, int)); 108 static void trap_fatal __P((struct trapframe *)); 109 void dblfault_handler __P((void)); 110 111 extern inthand_t IDTVEC(syscall); 112 113 #define MAX_TRAP_MSG 28 114 static char *trap_msg[] = { 115 "", /* 0 unused */ 116 "privileged instruction fault", /* 1 T_PRIVINFLT */ 117 "", /* 2 unused */ 118 "breakpoint instruction fault", /* 3 T_BPTFLT */ 119 "", /* 4 unused */ 120 "", /* 5 unused */ 121 "arithmetic trap", /* 6 T_ARITHTRAP */ 122 "system forced exception", /* 7 T_ASTFLT */ 123 "", /* 8 unused */ 124 "general protection fault", /* 9 T_PROTFLT */ 125 "trace trap", /* 10 T_TRCTRAP */ 126 "", /* 11 unused */ 127 "page fault", /* 12 T_PAGEFLT */ 128 "", /* 13 unused */ 129 "alignment fault", /* 14 T_ALIGNFLT */ 130 "", /* 15 unused */ 131 "", /* 16 unused */ 132 "", /* 17 unused */ 133 "integer divide fault", /* 18 T_DIVIDE */ 134 "non-maskable interrupt trap", /* 19 T_NMI */ 135 "overflow trap", /* 20 T_OFLOW */ 136 "FPU bounds check fault", /* 21 T_BOUND */ 137 "FPU device not available", /* 22 T_DNA */ 138 "double fault", /* 23 T_DOUBLEFLT */ 139 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 140 "invalid TSS fault", /* 25 T_TSSFLT */ 141 "segment not present fault", /* 26 T_SEGNPFLT */ 142 "stack fault", /* 27 T_STKFLT */ 143 "machine check trap", /* 28 T_MCHK */ 144 }; 145 146 static __inline void userret __P((struct proc *p, struct trapframe *frame, 147 u_quad_t oticks)); 148 149 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 150 extern struct gate_descriptor *t_idt; 151 extern int has_f00f_bug; 152 #endif 153 154 static __inline void 155 userret(p, frame, oticks) 156 struct proc *p; 157 struct trapframe *frame; 158 u_quad_t oticks; 159 { 160 int sig, s; 161 162 while ((sig = CURSIG(p)) != 0) 163 postsig(sig); 164 165 #if 0 166 if (!want_resched && 167 (p->p_priority <= p->p_usrpri) && 168 (p->p_rtprio.type == RTP_PRIO_NORMAL)) { 169 int newpriority; 170 p->p_estcpu += 1; 171 newpriority = PUSER + p->p_estcpu / 4 + 2 * p->p_nice; 172 newpriority = min(newpriority, MAXPRI); 173 p->p_usrpri = newpriority; 174 } 175 #endif 176 177 p->p_priority = p->p_usrpri; 178 if (want_resched) { 179 /* 180 * Since we are curproc, clock will normally just change 181 * our priority without moving us from one queue to another 182 * (since the running process is not on a queue.) 183 * If that happened after we setrunqueue ourselves but before we 184 * mi_switch()'ed, we might not be on the queue indicated by 185 * our priority. 186 */ 187 s = splhigh(); 188 setrunqueue(p); 189 p->p_stats->p_ru.ru_nivcsw++; 190 mi_switch(); 191 splx(s); 192 while ((sig = CURSIG(p)) != 0) 193 postsig(sig); 194 } 195 /* 196 * Charge system time if profiling. 197 */ 198 if (p->p_flag & P_PROFIL) 199 addupc_task(p, frame->tf_eip, 200 (u_int)(p->p_sticks - oticks) * psratio); 201 202 curpriority = p->p_priority; 203 } 204 205 /* 206 * Exception, fault, and trap interface to the FreeBSD kernel. 207 * This common code is called from assembly language IDT gate entry 208 * routines that prepare a suitable stack frame, and restore this 209 * frame after the exception has been processed. 210 */ 211 212 void 213 trap(frame) 214 struct trapframe frame; 215 { 216 struct proc *p = curproc; 217 u_quad_t sticks = 0; 218 int i = 0, ucode = 0, type, code; 219 #ifdef DEBUG 220 u_long eva; 221 #endif 222 223 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 224 restart: 225 #endif 226 type = frame.tf_trapno; 227 code = frame.tf_err; 228 229 #ifdef VM86 230 if (in_vm86call) { 231 if (frame.tf_eflags & PSL_VM && 232 (type == T_PROTFLT || type == T_STKFLT)) { 233 i = vm86_emulate((struct vm86frame *)&frame); 234 if (i != 0) 235 /* 236 * returns to original process 237 */ 238 vm86_trap((struct vm86frame *)&frame); 239 return; 240 } 241 switch (type) { 242 /* 243 * these traps want either a process context, or 244 * assume a normal userspace trap. 245 */ 246 case T_PROTFLT: 247 case T_SEGNPFLT: 248 trap_fatal(&frame); 249 return; 250 case T_TRCTRAP: 251 type = T_BPTFLT; /* kernel breakpoint */ 252 /* FALL THROUGH */ 253 } 254 goto kernel_trap; /* normal kernel trap handling */ 255 } 256 #endif 257 258 if ((ISPL(frame.tf_cs) == SEL_UPL) || (frame.tf_eflags & PSL_VM)) { 259 /* user trap */ 260 261 sticks = p->p_sticks; 262 p->p_md.md_regs = &frame; 263 264 switch (type) { 265 case T_PRIVINFLT: /* privileged instruction fault */ 266 ucode = type; 267 i = SIGILL; 268 break; 269 270 case T_BPTFLT: /* bpt instruction fault */ 271 case T_TRCTRAP: /* trace trap */ 272 frame.tf_eflags &= ~PSL_T; 273 i = SIGTRAP; 274 break; 275 276 case T_ARITHTRAP: /* arithmetic trap */ 277 ucode = code; 278 i = SIGFPE; 279 break; 280 281 case T_ASTFLT: /* Allow process switch */ 282 astoff(); 283 cnt.v_soft++; 284 if (p->p_flag & P_OWEUPC) { 285 p->p_flag &= ~P_OWEUPC; 286 addupc_task(p, p->p_stats->p_prof.pr_addr, 287 p->p_stats->p_prof.pr_ticks); 288 } 289 goto out; 290 291 /* 292 * The following two traps can happen in 293 * vm86 mode, and, if so, we want to handle 294 * them specially. 295 */ 296 case T_PROTFLT: /* general protection fault */ 297 case T_STKFLT: /* stack fault */ 298 #ifdef VM86 299 if (frame.tf_eflags & PSL_VM) { 300 i = vm86_emulate((struct vm86frame *)&frame); 301 if (i == 0) 302 goto out; 303 break; 304 } 305 #endif /* VM86 */ 306 /* FALL THROUGH */ 307 308 case T_SEGNPFLT: /* segment not present fault */ 309 case T_TSSFLT: /* invalid TSS fault */ 310 case T_DOUBLEFLT: /* double fault */ 311 default: 312 ucode = code + BUS_SEGM_FAULT ; 313 i = SIGBUS; 314 break; 315 316 case T_PAGEFLT: /* page fault */ 317 i = trap_pfault(&frame, TRUE); 318 if (i == -1) 319 return; 320 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 321 if (i == -2) 322 goto restart; 323 #endif 324 if (i == 0) 325 goto out; 326 327 ucode = T_PAGEFLT; 328 break; 329 330 case T_DIVIDE: /* integer divide fault */ 331 ucode = FPE_INTDIV_TRAP; 332 i = SIGFPE; 333 break; 334 335 #if NISA > 0 336 case T_NMI: 337 #ifdef POWERFAIL_NMI 338 goto handle_powerfail; 339 #else /* !POWERFAIL_NMI */ 340 #ifdef DDB 341 /* NMI can be hooked up to a pushbutton for debugging */ 342 printf ("NMI ... going to debugger\n"); 343 if (kdb_trap (type, 0, &frame)) 344 return; 345 #endif /* DDB */ 346 /* machine/parity/power fail/"kitchen sink" faults */ 347 if (isa_nmi(code) == 0) return; 348 panic("NMI indicates hardware failure"); 349 #endif /* POWERFAIL_NMI */ 350 #endif /* NISA > 0 */ 351 352 case T_OFLOW: /* integer overflow fault */ 353 ucode = FPE_INTOVF_TRAP; 354 i = SIGFPE; 355 break; 356 357 case T_BOUND: /* bounds check fault */ 358 ucode = FPE_SUBRNG_TRAP; 359 i = SIGFPE; 360 break; 361 362 case T_DNA: 363 #if NNPX > 0 364 /* if a transparent fault (due to context switch "late") */ 365 if (npxdna()) 366 return; 367 #endif 368 if (!pmath_emulate) { 369 i = SIGFPE; 370 ucode = FPE_FPU_NP_TRAP; 371 break; 372 } 373 i = (*pmath_emulate)(&frame); 374 if (i == 0) { 375 if (!(frame.tf_eflags & PSL_T)) 376 return; 377 frame.tf_eflags &= ~PSL_T; 378 i = SIGTRAP; 379 } 380 /* else ucode = emulator_only_knows() XXX */ 381 break; 382 383 case T_FPOPFLT: /* FPU operand fetch fault */ 384 ucode = T_FPOPFLT; 385 i = SIGILL; 386 break; 387 } 388 } else { 389 #ifdef VM86 390 kernel_trap: 391 #endif 392 /* kernel trap */ 393 394 switch (type) { 395 case T_PAGEFLT: /* page fault */ 396 (void) trap_pfault(&frame, FALSE); 397 return; 398 399 case T_DNA: 400 #if NNPX > 0 401 /* 402 * The kernel is apparently using npx for copying. 403 * XXX this should be fatal unless the kernel has 404 * registered such use. 405 */ 406 if (npxdna()) 407 return; 408 #endif 409 break; 410 411 case T_PROTFLT: /* general protection fault */ 412 case T_SEGNPFLT: /* segment not present fault */ 413 /* 414 * Invalid segment selectors and out of bounds 415 * %eip's and %esp's can be set up in user mode. 416 * This causes a fault in kernel mode when the 417 * kernel tries to return to user mode. We want 418 * to get this fault so that we can fix the 419 * problem here and not have to check all the 420 * selectors and pointers when the user changes 421 * them. 422 */ 423 #define MAYBE_DORETI_FAULT(where, whereto) \ 424 do { \ 425 if (frame.tf_eip == (int)where) { \ 426 frame.tf_eip = (int)whereto; \ 427 return; \ 428 } \ 429 } while (0) 430 431 if (intr_nesting_level == 0) { 432 /* 433 * Invalid %fs's and %gs's can be created using 434 * procfs or PT_SETREGS or by invalidating the 435 * underlying LDT entry. This causes a fault 436 * in kernel mode when the kernel attempts to 437 * switch contexts. Lose the bad context 438 * (XXX) so that we can continue, and generate 439 * a signal. 440 */ 441 if (frame.tf_eip == (int)cpu_switch_load_fs) { 442 curpcb->pcb_fs = 0; 443 psignal(p, SIGBUS); 444 return; 445 } 446 if (frame.tf_eip == (int)cpu_switch_load_gs) { 447 curpcb->pcb_gs = 0; 448 psignal(p, SIGBUS); 449 return; 450 } 451 MAYBE_DORETI_FAULT(doreti_iret, 452 doreti_iret_fault); 453 MAYBE_DORETI_FAULT(doreti_popl_ds, 454 doreti_popl_ds_fault); 455 MAYBE_DORETI_FAULT(doreti_popl_es, 456 doreti_popl_es_fault); 457 if (curpcb && curpcb->pcb_onfault) { 458 frame.tf_eip = (int)curpcb->pcb_onfault; 459 return; 460 } 461 } 462 break; 463 464 case T_TSSFLT: 465 /* 466 * PSL_NT can be set in user mode and isn't cleared 467 * automatically when the kernel is entered. This 468 * causes a TSS fault when the kernel attempts to 469 * `iret' because the TSS link is uninitialized. We 470 * want to get this fault so that we can fix the 471 * problem here and not every time the kernel is 472 * entered. 473 */ 474 if (frame.tf_eflags & PSL_NT) { 475 frame.tf_eflags &= ~PSL_NT; 476 return; 477 } 478 break; 479 480 case T_TRCTRAP: /* trace trap */ 481 if (frame.tf_eip == (int)IDTVEC(syscall)) { 482 /* 483 * We've just entered system mode via the 484 * syscall lcall. Continue single stepping 485 * silently until the syscall handler has 486 * saved the flags. 487 */ 488 return; 489 } 490 if (frame.tf_eip == (int)IDTVEC(syscall) + 1) { 491 /* 492 * The syscall handler has now saved the 493 * flags. Stop single stepping it. 494 */ 495 frame.tf_eflags &= ~PSL_T; 496 return; 497 } 498 /* 499 * Fall through. 500 */ 501 case T_BPTFLT: 502 /* 503 * If DDB is enabled, let it handle the debugger trap. 504 * Otherwise, debugger traps "can't happen". 505 */ 506 #ifdef DDB 507 if (kdb_trap (type, 0, &frame)) 508 return; 509 #endif 510 break; 511 512 #if NISA > 0 513 case T_NMI: 514 #ifdef POWERFAIL_NMI 515 #ifndef TIMER_FREQ 516 # define TIMER_FREQ 1193182 517 #endif 518 handle_powerfail: 519 { 520 static unsigned lastalert = 0; 521 522 if(time_second - lastalert > 10) 523 { 524 log(LOG_WARNING, "NMI: power fail\n"); 525 sysbeep(TIMER_FREQ/880, hz); 526 lastalert = time_second; 527 } 528 return; 529 } 530 #else /* !POWERFAIL_NMI */ 531 #ifdef DDB 532 /* NMI can be hooked up to a pushbutton for debugging */ 533 printf ("NMI ... going to debugger\n"); 534 if (kdb_trap (type, 0, &frame)) 535 return; 536 #endif /* DDB */ 537 /* machine/parity/power fail/"kitchen sink" faults */ 538 if (isa_nmi(code) == 0) return; 539 /* FALL THROUGH */ 540 #endif /* POWERFAIL_NMI */ 541 #endif /* NISA > 0 */ 542 } 543 544 trap_fatal(&frame); 545 return; 546 } 547 548 /* Translate fault for emulators (e.g. Linux) */ 549 if (*p->p_sysent->sv_transtrap) 550 i = (*p->p_sysent->sv_transtrap)(i, type); 551 552 trapsignal(p, i, ucode); 553 554 #ifdef DEBUG 555 eva = rcr2(); 556 if (type <= MAX_TRAP_MSG) { 557 uprintf("fatal process exception: %s", 558 trap_msg[type]); 559 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 560 uprintf(", fault VA = 0x%lx", eva); 561 uprintf("\n"); 562 } 563 #endif 564 565 out: 566 userret(p, &frame, sticks); 567 } 568 569 #ifdef notyet 570 /* 571 * This version doesn't allow a page fault to user space while 572 * in the kernel. The rest of the kernel needs to be made "safe" 573 * before this can be used. I think the only things remaining 574 * to be made safe are the iBCS2 code and the process tracing/ 575 * debugging code. 576 */ 577 static int 578 trap_pfault(frame, usermode) 579 struct trapframe *frame; 580 int usermode; 581 { 582 vm_offset_t va; 583 struct vmspace *vm = NULL; 584 vm_map_t map = 0; 585 int rv = 0; 586 vm_prot_t ftype; 587 int eva; 588 struct proc *p = curproc; 589 590 if (frame->tf_err & PGEX_W) 591 ftype = VM_PROT_READ | VM_PROT_WRITE; 592 else 593 ftype = VM_PROT_READ; 594 595 eva = rcr2(); 596 va = trunc_page((vm_offset_t)eva); 597 598 if (va < VM_MIN_KERNEL_ADDRESS) { 599 vm_offset_t v; 600 vm_page_t mpte; 601 602 if (p == NULL || 603 (!usermode && va < VM_MAXUSER_ADDRESS && 604 (intr_nesting_level != 0 || curpcb == NULL || 605 curpcb->pcb_onfault == NULL))) { 606 trap_fatal(frame); 607 return (-1); 608 } 609 610 /* 611 * This is a fault on non-kernel virtual memory. 612 * vm is initialized above to NULL. If curproc is NULL 613 * or curproc->p_vmspace is NULL the fault is fatal. 614 */ 615 vm = p->p_vmspace; 616 if (vm == NULL) 617 goto nogo; 618 619 map = &vm->vm_map; 620 621 /* 622 * Keep swapout from messing with us during this 623 * critical time. 624 */ 625 ++p->p_lock; 626 627 /* 628 * Grow the stack if necessary 629 */ 630 if ((caddr_t)va > vm->vm_maxsaddr 631 && (caddr_t)va < (caddr_t)USRSTACK) { 632 if (!grow(p, va)) { 633 rv = KERN_FAILURE; 634 --p->p_lock; 635 goto nogo; 636 } 637 } 638 639 /* Fault in the user page: */ 640 rv = vm_fault(map, va, ftype, 641 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 642 643 --p->p_lock; 644 } else { 645 /* 646 * Don't allow user-mode faults in kernel address space. 647 */ 648 if (usermode) 649 goto nogo; 650 651 /* 652 * Since we know that kernel virtual address addresses 653 * always have pte pages mapped, we just have to fault 654 * the page. 655 */ 656 rv = vm_fault(kernel_map, va, ftype, FALSE); 657 } 658 659 if (rv == KERN_SUCCESS) 660 return (0); 661 nogo: 662 if (!usermode) { 663 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 664 frame->tf_eip = (int)curpcb->pcb_onfault; 665 return (0); 666 } 667 trap_fatal(frame); 668 return (-1); 669 } 670 671 /* kludge to pass faulting virtual address to sendsig */ 672 frame->tf_err = eva; 673 674 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 675 } 676 #endif 677 678 int 679 trap_pfault(frame, usermode) 680 struct trapframe *frame; 681 int usermode; 682 { 683 vm_offset_t va; 684 struct vmspace *vm = NULL; 685 vm_map_t map = 0; 686 int rv = 0; 687 vm_prot_t ftype; 688 int eva; 689 struct proc *p = curproc; 690 691 eva = rcr2(); 692 va = trunc_page((vm_offset_t)eva); 693 694 if (va >= KERNBASE) { 695 /* 696 * Don't allow user-mode faults in kernel address space. 697 * An exception: if the faulting address is the invalid 698 * instruction entry in the IDT, then the Intel Pentium 699 * F00F bug workaround was triggered, and we need to 700 * treat it is as an illegal instruction, and not a page 701 * fault. 702 */ 703 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 704 if ((eva == (unsigned int)&t_idt[6]) && has_f00f_bug) { 705 frame->tf_trapno = T_PRIVINFLT; 706 return -2; 707 } 708 #endif 709 if (usermode) 710 goto nogo; 711 712 map = kernel_map; 713 } else { 714 /* 715 * This is a fault on non-kernel virtual memory. 716 * vm is initialized above to NULL. If curproc is NULL 717 * or curproc->p_vmspace is NULL the fault is fatal. 718 */ 719 if (p != NULL) 720 vm = p->p_vmspace; 721 722 if (vm == NULL) 723 goto nogo; 724 725 map = &vm->vm_map; 726 } 727 728 if (frame->tf_err & PGEX_W) 729 ftype = VM_PROT_READ | VM_PROT_WRITE; 730 else 731 ftype = VM_PROT_READ; 732 733 if (map != kernel_map) { 734 /* 735 * Keep swapout from messing with us during this 736 * critical time. 737 */ 738 ++p->p_lock; 739 740 /* 741 * Grow the stack if necessary 742 */ 743 if ((caddr_t)va > vm->vm_maxsaddr 744 && (caddr_t)va < (caddr_t)USRSTACK) { 745 if (!grow(p, va)) { 746 rv = KERN_FAILURE; 747 --p->p_lock; 748 goto nogo; 749 } 750 } 751 752 /* Fault in the user page: */ 753 rv = vm_fault(map, va, ftype, 754 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 755 756 --p->p_lock; 757 } else { 758 /* 759 * Don't have to worry about process locking or stacks in the kernel. 760 */ 761 rv = vm_fault(map, va, ftype, FALSE); 762 } 763 764 if (rv == KERN_SUCCESS) 765 return (0); 766 nogo: 767 if (!usermode) { 768 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 769 frame->tf_eip = (int)curpcb->pcb_onfault; 770 return (0); 771 } 772 trap_fatal(frame); 773 return (-1); 774 } 775 776 /* kludge to pass faulting virtual address to sendsig */ 777 frame->tf_err = eva; 778 779 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 780 } 781 782 static void 783 trap_fatal(frame) 784 struct trapframe *frame; 785 { 786 int code, type, eva, ss, esp; 787 struct soft_segment_descriptor softseg; 788 789 code = frame->tf_err; 790 type = frame->tf_trapno; 791 eva = rcr2(); 792 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 793 794 if (type <= MAX_TRAP_MSG) 795 printf("\n\nFatal trap %d: %s while in %s mode\n", 796 type, trap_msg[type], 797 frame->tf_eflags & PSL_VM ? "vm86" : 798 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 799 #ifdef SMP 800 /* three seperate prints in case of a trap on an unmapped page */ 801 printf("mp_lock = %08x; ", mp_lock); 802 printf("cpuid = %d; ", cpuid); 803 printf("lapic.id = %08x\n", lapic.id); 804 #endif 805 if (type == T_PAGEFLT) { 806 printf("fault virtual address = 0x%x\n", eva); 807 printf("fault code = %s %s, %s\n", 808 code & PGEX_U ? "user" : "supervisor", 809 code & PGEX_W ? "write" : "read", 810 code & PGEX_P ? "protection violation" : "page not present"); 811 } 812 printf("instruction pointer = 0x%x:0x%x\n", 813 frame->tf_cs & 0xffff, frame->tf_eip); 814 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 815 ss = frame->tf_ss & 0xffff; 816 esp = frame->tf_esp; 817 } else { 818 ss = GSEL(GDATA_SEL, SEL_KPL); 819 esp = (int)&frame->tf_esp; 820 } 821 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 822 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 823 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 824 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 825 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 826 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 827 softseg.ssd_gran); 828 printf("processor eflags = "); 829 if (frame->tf_eflags & PSL_T) 830 printf("trace trap, "); 831 if (frame->tf_eflags & PSL_I) 832 printf("interrupt enabled, "); 833 if (frame->tf_eflags & PSL_NT) 834 printf("nested task, "); 835 if (frame->tf_eflags & PSL_RF) 836 printf("resume, "); 837 if (frame->tf_eflags & PSL_VM) 838 printf("vm86, "); 839 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 840 printf("current process = "); 841 if (curproc) { 842 printf("%lu (%s)\n", 843 (u_long)curproc->p_pid, curproc->p_comm ? 844 curproc->p_comm : ""); 845 } else { 846 printf("Idle\n"); 847 } 848 printf("interrupt mask = "); 849 if ((cpl & net_imask) == net_imask) 850 printf("net "); 851 if ((cpl & tty_imask) == tty_imask) 852 printf("tty "); 853 if ((cpl & bio_imask) == bio_imask) 854 printf("bio "); 855 if ((cpl & cam_imask) == cam_imask) 856 printf("cam "); 857 if (cpl == 0) 858 printf("none"); 859 #ifdef SMP 860 /** 861 * XXX FIXME: 862 * we probably SHOULD have stopped the other CPUs before now! 863 * another CPU COULD have been touching cpl at this moment... 864 */ 865 printf(" <- SMP: XXX"); 866 #endif 867 printf("\n"); 868 869 #ifdef KDB 870 if (kdb_trap(&psl)) 871 return; 872 #endif 873 #ifdef DDB 874 if (kdb_trap (type, 0, frame)) 875 return; 876 #endif 877 printf("trap number = %d\n", type); 878 if (type <= MAX_TRAP_MSG) 879 panic(trap_msg[type]); 880 else 881 panic("unknown/reserved trap"); 882 } 883 884 /* 885 * Double fault handler. Called when a fault occurs while writing 886 * a frame for a trap/exception onto the stack. This usually occurs 887 * when the stack overflows (such is the case with infinite recursion, 888 * for example). 889 * 890 * XXX Note that the current PTD gets replaced by IdlePTD when the 891 * task switch occurs. This means that the stack that was active at 892 * the time of the double fault is not available at <kstack> unless 893 * the machine was idle when the double fault occurred. The downside 894 * of this is that "trace <ebp>" in ddb won't work. 895 */ 896 void 897 dblfault_handler() 898 { 899 printf("\nFatal double fault:\n"); 900 printf("eip = 0x%x\n", common_tss.tss_eip); 901 printf("esp = 0x%x\n", common_tss.tss_esp); 902 printf("ebp = 0x%x\n", common_tss.tss_ebp); 903 #ifdef SMP 904 /* three seperate prints in case of a trap on an unmapped page */ 905 printf("mp_lock = %08x; ", mp_lock); 906 printf("cpuid = %d; ", cpuid); 907 printf("lapic.id = %08x\n", lapic.id); 908 #endif 909 panic("double fault"); 910 } 911 912 /* 913 * Compensate for 386 brain damage (missing URKR). 914 * This is a little simpler than the pagefault handler in trap() because 915 * it the page tables have already been faulted in and high addresses 916 * are thrown out early for other reasons. 917 */ 918 int trapwrite(addr) 919 unsigned addr; 920 { 921 struct proc *p; 922 vm_offset_t va; 923 struct vmspace *vm; 924 int rv; 925 926 va = trunc_page((vm_offset_t)addr); 927 /* 928 * XXX - MAX is END. Changed > to >= for temp. fix. 929 */ 930 if (va >= VM_MAXUSER_ADDRESS) 931 return (1); 932 933 p = curproc; 934 vm = p->p_vmspace; 935 936 ++p->p_lock; 937 938 if ((caddr_t)va >= vm->vm_maxsaddr 939 && (caddr_t)va < (caddr_t)USRSTACK) { 940 if (!grow(p, va)) { 941 --p->p_lock; 942 return (1); 943 } 944 } 945 946 /* 947 * fault the data page 948 */ 949 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, VM_FAULT_DIRTY); 950 951 --p->p_lock; 952 953 if (rv != KERN_SUCCESS) 954 return 1; 955 956 return (0); 957 } 958 959 /* 960 * System call request from POSIX system call gate interface to kernel. 961 * Like trap(), argument is call by reference. 962 */ 963 void 964 syscall(frame) 965 struct trapframe frame; 966 { 967 caddr_t params; 968 int i; 969 struct sysent *callp; 970 struct proc *p = curproc; 971 u_quad_t sticks; 972 int error; 973 int args[8]; 974 u_int code; 975 976 #ifdef DIAGNOSTIC 977 if (ISPL(frame.tf_cs) != SEL_UPL) 978 panic("syscall"); 979 #endif 980 sticks = p->p_sticks; 981 p->p_md.md_regs = &frame; 982 params = (caddr_t)frame.tf_esp + sizeof(int); 983 code = frame.tf_eax; 984 if (p->p_sysent->sv_prepsyscall) { 985 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); 986 } else { 987 /* 988 * Need to check if this is a 32 bit or 64 bit syscall. 989 */ 990 if (code == SYS_syscall) { 991 /* 992 * Code is first argument, followed by actual args. 993 */ 994 code = fuword(params); 995 params += sizeof(int); 996 } else if (code == SYS___syscall) { 997 /* 998 * Like syscall, but code is a quad, so as to maintain 999 * quad alignment for the rest of the arguments. 1000 */ 1001 code = fuword(params); 1002 params += sizeof(quad_t); 1003 } 1004 } 1005 1006 if (p->p_sysent->sv_mask) 1007 code &= p->p_sysent->sv_mask; 1008 1009 if (code >= p->p_sysent->sv_size) 1010 callp = &p->p_sysent->sv_table[0]; 1011 else 1012 callp = &p->p_sysent->sv_table[code]; 1013 1014 if (params && (i = callp->sy_narg * sizeof(int)) && 1015 (error = copyin(params, (caddr_t)args, (u_int)i))) { 1016 #ifdef KTRACE 1017 if (KTRPOINT(p, KTR_SYSCALL)) 1018 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 1019 #endif 1020 goto bad; 1021 } 1022 #ifdef KTRACE 1023 if (KTRPOINT(p, KTR_SYSCALL)) 1024 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 1025 #endif 1026 p->p_retval[0] = 0; 1027 p->p_retval[1] = frame.tf_edx; 1028 1029 STOPEVENT(p, S_SCE, callp->sy_narg); 1030 1031 error = (*callp->sy_call)(p, args); 1032 1033 switch (error) { 1034 1035 case 0: 1036 /* 1037 * Reinitialize proc pointer `p' as it may be different 1038 * if this is a child returning from fork syscall. 1039 */ 1040 p = curproc; 1041 frame.tf_eax = p->p_retval[0]; 1042 frame.tf_edx = p->p_retval[1]; 1043 frame.tf_eflags &= ~PSL_C; 1044 break; 1045 1046 case ERESTART: 1047 /* 1048 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 1049 * int 0x80 is 2 bytes. We saved this in tf_err. 1050 */ 1051 frame.tf_eip -= frame.tf_err; 1052 break; 1053 1054 case EJUSTRETURN: 1055 break; 1056 1057 default: 1058 bad: 1059 if (p->p_sysent->sv_errsize) 1060 if (error >= p->p_sysent->sv_errsize) 1061 error = -1; /* XXX */ 1062 else 1063 error = p->p_sysent->sv_errtbl[error]; 1064 frame.tf_eax = error; 1065 frame.tf_eflags |= PSL_C; 1066 break; 1067 } 1068 1069 if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) { 1070 /* Traced syscall. */ 1071 frame.tf_eflags &= ~PSL_T; 1072 trapsignal(p, SIGTRAP, 0); 1073 } 1074 1075 userret(p, &frame, sticks); 1076 1077 #ifdef KTRACE 1078 if (KTRPOINT(p, KTR_SYSRET)) 1079 ktrsysret(p->p_tracep, code, error, p->p_retval[0]); 1080 #endif 1081 1082 /* 1083 * This works because errno is findable through the 1084 * register set. If we ever support an emulation where this 1085 * is not the case, this code will need to be revisited. 1086 */ 1087 STOPEVENT(p, S_SCX, code); 1088 1089 } 1090 1091 /* 1092 * Simplified back end of syscall(), used when returning from fork() 1093 * directly into user mode. 1094 */ 1095 void 1096 fork_return(p, frame) 1097 struct proc *p; 1098 struct trapframe frame; 1099 { 1100 frame.tf_eax = 0; /* Child returns zero */ 1101 frame.tf_eflags &= ~PSL_C; /* success */ 1102 frame.tf_edx = 1; 1103 1104 userret(p, &frame, 0); 1105 #ifdef KTRACE 1106 if (KTRPOINT(p, KTR_SYSRET)) 1107 ktrsysret(p->p_tracep, SYS_fork, 0, 0); 1108 #endif 1109 } 1110