subr_syscall.c revision 46568
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 1.136 1999/04/28 01:03:26 luoqi 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_clock.h" 49#include "opt_trap.h" 50#include "opt_vm86.h" 51 52#include <sys/param.h> 53#include <sys/systm.h> 54#include <sys/proc.h> 55#include <sys/pioctl.h> 56#include <sys/kernel.h> 57#include <sys/resourcevar.h> 58#include <sys/signalvar.h> 59#include <sys/syscall.h> 60#include <sys/sysent.h> 61#include <sys/uio.h> 62#include <sys/vmmeter.h> 63#ifdef KTRACE 64#include <sys/ktrace.h> 65#endif 66 67#include <vm/vm.h> 68#include <vm/vm_param.h> 69#include <vm/vm_prot.h> 70#include <sys/lock.h> 71#include <vm/pmap.h> 72#include <vm/vm_kern.h> 73#include <vm/vm_map.h> 74#include <vm/vm_page.h> 75#include <vm/vm_extern.h> 76 77#include <machine/cpu.h> 78#include <machine/ipl.h> 79#include <machine/md_var.h> 80#include <machine/pcb.h> 81#ifdef SMP 82#include <machine/smp.h> 83#endif 84#include <machine/tss.h> 85 86#include <i386/isa/intr_machdep.h> 87 88#ifdef POWERFAIL_NMI 89#include <sys/syslog.h> 90#include <machine/clock.h> 91#endif 92 93#ifdef VM86 94#include <machine/vm86.h> 95#endif 96 97#ifdef DDB 98 extern int in_Debugger, debugger_on_panic; 99#endif 100 101#include "isa.h" 102#include "npx.h" 103 104int (*pmath_emulate) __P((struct trapframe *)); 105 106extern void trap __P((struct trapframe frame)); 107extern int trapwrite __P((unsigned addr)); 108extern void syscall __P((struct trapframe frame)); 109 110static int trap_pfault __P((struct trapframe *, int, vm_offset_t)); 111static void trap_fatal __P((struct trapframe *, vm_offset_t)); 112void dblfault_handler __P((void)); 113 114extern inthand_t IDTVEC(syscall); 115 116#define MAX_TRAP_MSG 28 117static char *trap_msg[] = { 118 "", /* 0 unused */ 119 "privileged instruction fault", /* 1 T_PRIVINFLT */ 120 "", /* 2 unused */ 121 "breakpoint instruction fault", /* 3 T_BPTFLT */ 122 "", /* 4 unused */ 123 "", /* 5 unused */ 124 "arithmetic trap", /* 6 T_ARITHTRAP */ 125 "system forced exception", /* 7 T_ASTFLT */ 126 "", /* 8 unused */ 127 "general protection fault", /* 9 T_PROTFLT */ 128 "trace trap", /* 10 T_TRCTRAP */ 129 "", /* 11 unused */ 130 "page fault", /* 12 T_PAGEFLT */ 131 "", /* 13 unused */ 132 "alignment fault", /* 14 T_ALIGNFLT */ 133 "", /* 15 unused */ 134 "", /* 16 unused */ 135 "", /* 17 unused */ 136 "integer divide fault", /* 18 T_DIVIDE */ 137 "non-maskable interrupt trap", /* 19 T_NMI */ 138 "overflow trap", /* 20 T_OFLOW */ 139 "FPU bounds check fault", /* 21 T_BOUND */ 140 "FPU device not available", /* 22 T_DNA */ 141 "double fault", /* 23 T_DOUBLEFLT */ 142 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 143 "invalid TSS fault", /* 25 T_TSSFLT */ 144 "segment not present fault", /* 26 T_SEGNPFLT */ 145 "stack fault", /* 27 T_STKFLT */ 146 "machine check trap", /* 28 T_MCHK */ 147}; 148 149static __inline void userret __P((struct proc *p, struct trapframe *frame, 150 u_quad_t oticks)); 151 152#if defined(I586_CPU) && !defined(NO_F00F_HACK) 153extern struct gate_descriptor *t_idt; 154extern int has_f00f_bug; 155#endif 156 157static __inline void 158userret(p, frame, oticks) 159 struct proc *p; 160 struct trapframe *frame; 161 u_quad_t oticks; 162{ 163 int sig, s; 164 165 while ((sig = CURSIG(p)) != 0) 166 postsig(sig); 167 168#if 0 169 if (!want_resched && 170 (p->p_priority <= p->p_usrpri) && 171 (p->p_rtprio.type == RTP_PRIO_NORMAL)) { 172 int newpriority; 173 p->p_estcpu += 1; 174 newpriority = PUSER + p->p_estcpu / 4 + 2 * p->p_nice; 175 newpriority = min(newpriority, MAXPRI); 176 p->p_usrpri = newpriority; 177 } 178#endif 179 180 p->p_priority = p->p_usrpri; 181 if (want_resched) { 182 /* 183 * Since we are curproc, clock will normally just change 184 * our priority without moving us from one queue to another 185 * (since the running process is not on a queue.) 186 * If that happened after we setrunqueue ourselves but before we 187 * mi_switch()'ed, we might not be on the queue indicated by 188 * our priority. 189 */ 190 s = splhigh(); 191 setrunqueue(p); 192 p->p_stats->p_ru.ru_nivcsw++; 193 mi_switch(); 194 splx(s); 195 while ((sig = CURSIG(p)) != 0) 196 postsig(sig); 197 } 198 /* 199 * Charge system time if profiling. 200 */ 201 if (p->p_flag & P_PROFIL) 202 addupc_task(p, frame->tf_eip, 203 (u_int)(p->p_sticks - oticks) * psratio); 204 205 curpriority = p->p_priority; 206} 207 208/* 209 * Exception, fault, and trap interface to the FreeBSD kernel. 210 * This common code is called from assembly language IDT gate entry 211 * routines that prepare a suitable stack frame, and restore this 212 * frame after the exception has been processed. 213 */ 214 215void 216trap(frame) 217 struct trapframe frame; 218{ 219 struct proc *p = curproc; 220 u_quad_t sticks = 0; 221 int i = 0, ucode = 0, type, code; 222 vm_offset_t eva; 223 224 if (!(frame.tf_eflags & PSL_I)) { 225 /* 226 * Buggy application or kernel code has disabled interrupts 227 * and then trapped. Enabling interrupts now is wrong, but 228 * it is better than running with interrupts disabled until 229 * they are accidentally enabled later. 230 */ 231 type = frame.tf_trapno; 232 if (ISPL(frame.tf_cs) == SEL_UPL || (frame.tf_eflags & PSL_VM)) 233 printf( 234 "pid %ld (%s): trap %d with interrupts disabled\n", 235 (long)curproc->p_pid, curproc->p_comm, type); 236 else if (type != T_BPTFLT && type != T_TRCTRAP) 237 /* 238 * XXX not quite right, since this may be for a 239 * multiple fault in user mode. 240 */ 241 printf("kernel trap %d with interrupts disabled\n", 242 type); 243 enable_intr(); 244 } 245 246 eva = 0; 247 if (frame.tf_trapno == T_PAGEFLT) { 248 /* 249 * For some Cyrix CPUs, %cr2 is clobbered by interrupts. 250 * This problem is worked around by using an interrupt 251 * gate for the pagefault handler. We are finally ready 252 * to read %cr2 and then must reenable interrupts. 253 * 254 * XXX this should be in the switch statement, but the 255 * NO_FOOF_HACK and VM86 goto and ifdefs obfuscate the 256 * flow of control too much for this to be obviously 257 * correct. 258 */ 259 eva = rcr2(); 260 enable_intr(); 261 } 262 263#if defined(I586_CPU) && !defined(NO_F00F_HACK) 264restart: 265#endif 266 type = frame.tf_trapno; 267 code = frame.tf_err; 268 269#ifdef VM86 270 if (in_vm86call) { 271 if (frame.tf_eflags & PSL_VM && 272 (type == T_PROTFLT || type == T_STKFLT)) { 273 i = vm86_emulate((struct vm86frame *)&frame); 274 if (i != 0) 275 /* 276 * returns to original process 277 */ 278 vm86_trap((struct vm86frame *)&frame); 279 return; 280 } 281 switch (type) { 282 /* 283 * these traps want either a process context, or 284 * assume a normal userspace trap. 285 */ 286 case T_PROTFLT: 287 case T_SEGNPFLT: 288 trap_fatal(&frame, eva); 289 return; 290 case T_TRCTRAP: 291 type = T_BPTFLT; /* kernel breakpoint */ 292 /* FALL THROUGH */ 293 } 294 goto kernel_trap; /* normal kernel trap handling */ 295 } 296#endif 297 298 if ((ISPL(frame.tf_cs) == SEL_UPL) || (frame.tf_eflags & PSL_VM)) { 299 /* user trap */ 300 301 sticks = p->p_sticks; 302 p->p_md.md_regs = &frame; 303 304 switch (type) { 305 case T_PRIVINFLT: /* privileged instruction fault */ 306 ucode = type; 307 i = SIGILL; 308 break; 309 310 case T_BPTFLT: /* bpt instruction fault */ 311 case T_TRCTRAP: /* trace trap */ 312 frame.tf_eflags &= ~PSL_T; 313 i = SIGTRAP; 314 break; 315 316 case T_ARITHTRAP: /* arithmetic trap */ 317 ucode = code; 318 i = SIGFPE; 319 break; 320 321 case T_ASTFLT: /* Allow process switch */ 322 astoff(); 323 cnt.v_soft++; 324 if (p->p_flag & P_OWEUPC) { 325 p->p_flag &= ~P_OWEUPC; 326 addupc_task(p, p->p_stats->p_prof.pr_addr, 327 p->p_stats->p_prof.pr_ticks); 328 } 329 goto out; 330 331 /* 332 * The following two traps can happen in 333 * vm86 mode, and, if so, we want to handle 334 * them specially. 335 */ 336 case T_PROTFLT: /* general protection fault */ 337 case T_STKFLT: /* stack fault */ 338#ifdef VM86 339 if (frame.tf_eflags & PSL_VM) { 340 i = vm86_emulate((struct vm86frame *)&frame); 341 if (i == 0) 342 goto out; 343 break; 344 } 345#endif /* VM86 */ 346 /* FALL THROUGH */ 347 348 case T_SEGNPFLT: /* segment not present fault */ 349 case T_TSSFLT: /* invalid TSS fault */ 350 case T_DOUBLEFLT: /* double fault */ 351 default: 352 ucode = code + BUS_SEGM_FAULT ; 353 i = SIGBUS; 354 break; 355 356 case T_PAGEFLT: /* page fault */ 357 i = trap_pfault(&frame, TRUE, eva); 358 if (i == -1) 359 return; 360#if defined(I586_CPU) && !defined(NO_F00F_HACK) 361 if (i == -2) 362 goto restart; 363#endif 364 if (i == 0) 365 goto out; 366 367 ucode = T_PAGEFLT; 368 break; 369 370 case T_DIVIDE: /* integer divide fault */ 371 ucode = FPE_INTDIV_TRAP; 372 i = SIGFPE; 373 break; 374 375#if NISA > 0 376 case T_NMI: 377#ifdef POWERFAIL_NMI 378 goto handle_powerfail; 379#else /* !POWERFAIL_NMI */ 380#ifdef DDB 381 /* NMI can be hooked up to a pushbutton for debugging */ 382 printf ("NMI ... going to debugger\n"); 383 if (kdb_trap (type, 0, &frame)) 384 return; 385#endif /* DDB */ 386 /* machine/parity/power fail/"kitchen sink" faults */ 387 if (isa_nmi(code) == 0) return; 388 panic("NMI indicates hardware failure"); 389#endif /* POWERFAIL_NMI */ 390#endif /* NISA > 0 */ 391 392 case T_OFLOW: /* integer overflow fault */ 393 ucode = FPE_INTOVF_TRAP; 394 i = SIGFPE; 395 break; 396 397 case T_BOUND: /* bounds check fault */ 398 ucode = FPE_SUBRNG_TRAP; 399 i = SIGFPE; 400 break; 401 402 case T_DNA: 403#if NNPX > 0 404 /* if a transparent fault (due to context switch "late") */ 405 if (npxdna()) 406 return; 407#endif 408 if (!pmath_emulate) { 409 i = SIGFPE; 410 ucode = FPE_FPU_NP_TRAP; 411 break; 412 } 413 i = (*pmath_emulate)(&frame); 414 if (i == 0) { 415 if (!(frame.tf_eflags & PSL_T)) 416 return; 417 frame.tf_eflags &= ~PSL_T; 418 i = SIGTRAP; 419 } 420 /* else ucode = emulator_only_knows() XXX */ 421 break; 422 423 case T_FPOPFLT: /* FPU operand fetch fault */ 424 ucode = T_FPOPFLT; 425 i = SIGILL; 426 break; 427 } 428 } else { 429#ifdef VM86 430kernel_trap: 431#endif 432 /* kernel trap */ 433 434 switch (type) { 435 case T_PAGEFLT: /* page fault */ 436 (void) trap_pfault(&frame, FALSE, eva); 437 return; 438 439 case T_DNA: 440#if NNPX > 0 441 /* 442 * The kernel is apparently using npx for copying. 443 * XXX this should be fatal unless the kernel has 444 * registered such use. 445 */ 446 if (npxdna()) 447 return; 448#endif 449 break; 450 451 case T_PROTFLT: /* general protection fault */ 452 case T_SEGNPFLT: /* segment not present fault */ 453 /* 454 * Invalid segment selectors and out of bounds 455 * %eip's and %esp's can be set up in user mode. 456 * This causes a fault in kernel mode when the 457 * kernel tries to return to user mode. We want 458 * to get this fault so that we can fix the 459 * problem here and not have to check all the 460 * selectors and pointers when the user changes 461 * them. 462 */ 463#define MAYBE_DORETI_FAULT(where, whereto) \ 464 do { \ 465 if (frame.tf_eip == (int)where) { \ 466 frame.tf_eip = (int)whereto; \ 467 return; \ 468 } \ 469 } while (0) 470 471 if (intr_nesting_level == 0) { 472 /* 473 * Invalid %fs's and %gs's can be created using 474 * procfs or PT_SETREGS or by invalidating the 475 * underlying LDT entry. This causes a fault 476 * in kernel mode when the kernel attempts to 477 * switch contexts. Lose the bad context 478 * (XXX) so that we can continue, and generate 479 * a signal. 480 */ 481 if (frame.tf_eip == (int)cpu_switch_load_gs) { 482 curpcb->pcb_gs = 0; 483 psignal(p, SIGBUS); 484 return; 485 } 486 MAYBE_DORETI_FAULT(doreti_iret, 487 doreti_iret_fault); 488 MAYBE_DORETI_FAULT(doreti_popl_ds, 489 doreti_popl_ds_fault); 490 MAYBE_DORETI_FAULT(doreti_popl_es, 491 doreti_popl_es_fault); 492 MAYBE_DORETI_FAULT(doreti_popl_fs, 493 doreti_popl_fs_fault); 494 if (curpcb && curpcb->pcb_onfault) { 495 frame.tf_eip = (int)curpcb->pcb_onfault; 496 return; 497 } 498 } 499 break; 500 501 case T_TSSFLT: 502 /* 503 * PSL_NT can be set in user mode and isn't cleared 504 * automatically when the kernel is entered. This 505 * causes a TSS fault when the kernel attempts to 506 * `iret' because the TSS link is uninitialized. We 507 * want to get this fault so that we can fix the 508 * problem here and not every time the kernel is 509 * entered. 510 */ 511 if (frame.tf_eflags & PSL_NT) { 512 frame.tf_eflags &= ~PSL_NT; 513 return; 514 } 515 break; 516 517 case T_TRCTRAP: /* trace trap */ 518 if (frame.tf_eip == (int)IDTVEC(syscall)) { 519 /* 520 * We've just entered system mode via the 521 * syscall lcall. Continue single stepping 522 * silently until the syscall handler has 523 * saved the flags. 524 */ 525 return; 526 } 527 if (frame.tf_eip == (int)IDTVEC(syscall) + 1) { 528 /* 529 * The syscall handler has now saved the 530 * flags. Stop single stepping it. 531 */ 532 frame.tf_eflags &= ~PSL_T; 533 return; 534 } 535 /* 536 * Fall through. 537 */ 538 case T_BPTFLT: 539 /* 540 * If DDB is enabled, let it handle the debugger trap. 541 * Otherwise, debugger traps "can't happen". 542 */ 543#ifdef DDB 544 if (kdb_trap (type, 0, &frame)) 545 return; 546#endif 547 break; 548 549#if NISA > 0 550 case T_NMI: 551#ifdef POWERFAIL_NMI 552#ifndef TIMER_FREQ 553# define TIMER_FREQ 1193182 554#endif 555 handle_powerfail: 556 { 557 static unsigned lastalert = 0; 558 559 if(time_second - lastalert > 10) 560 { 561 log(LOG_WARNING, "NMI: power fail\n"); 562 sysbeep(TIMER_FREQ/880, hz); 563 lastalert = time_second; 564 } 565 return; 566 } 567#else /* !POWERFAIL_NMI */ 568#ifdef DDB 569 /* NMI can be hooked up to a pushbutton for debugging */ 570 printf ("NMI ... going to debugger\n"); 571 if (kdb_trap (type, 0, &frame)) 572 return; 573#endif /* DDB */ 574 /* machine/parity/power fail/"kitchen sink" faults */ 575 if (isa_nmi(code) == 0) return; 576 /* FALL THROUGH */ 577#endif /* POWERFAIL_NMI */ 578#endif /* NISA > 0 */ 579 } 580 581 trap_fatal(&frame, eva); 582 return; 583 } 584 585 /* Translate fault for emulators (e.g. Linux) */ 586 if (*p->p_sysent->sv_transtrap) 587 i = (*p->p_sysent->sv_transtrap)(i, type); 588 589 trapsignal(p, i, ucode); 590 591#ifdef DEBUG 592 if (type <= MAX_TRAP_MSG) { 593 uprintf("fatal process exception: %s", 594 trap_msg[type]); 595 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 596 uprintf(", fault VA = 0x%lx", (u_long)eva); 597 uprintf("\n"); 598 } 599#endif 600 601out: 602 userret(p, &frame, sticks); 603} 604 605#ifdef notyet 606/* 607 * This version doesn't allow a page fault to user space while 608 * in the kernel. The rest of the kernel needs to be made "safe" 609 * before this can be used. I think the only things remaining 610 * to be made safe are the iBCS2 code and the process tracing/ 611 * debugging code. 612 */ 613static int 614trap_pfault(frame, usermode, eva) 615 struct trapframe *frame; 616 int usermode; 617 vm_offset_t eva; 618{ 619 vm_offset_t va; 620 struct vmspace *vm = NULL; 621 vm_map_t map = 0; 622 int rv = 0; 623 vm_prot_t ftype; 624 struct proc *p = curproc; 625 626 if (frame->tf_err & PGEX_W) 627 ftype = VM_PROT_READ | VM_PROT_WRITE; 628 else 629 ftype = VM_PROT_READ; 630 631 va = trunc_page(eva); 632 if (va < VM_MIN_KERNEL_ADDRESS) { 633 vm_offset_t v; 634 vm_page_t mpte; 635 636 if (p == NULL || 637 (!usermode && va < VM_MAXUSER_ADDRESS && 638 (intr_nesting_level != 0 || curpcb == NULL || 639 curpcb->pcb_onfault == NULL))) { 640 trap_fatal(frame, eva); 641 return (-1); 642 } 643 644 /* 645 * This is a fault on non-kernel virtual memory. 646 * vm is initialized above to NULL. If curproc is NULL 647 * or curproc->p_vmspace is NULL the fault is fatal. 648 */ 649 vm = p->p_vmspace; 650 if (vm == NULL) 651 goto nogo; 652 653 map = &vm->vm_map; 654 655 /* 656 * Keep swapout from messing with us during this 657 * critical time. 658 */ 659 ++p->p_lock; 660 661 /* 662 * Grow the stack if necessary 663 */ 664 /* grow_stack returns false only if va falls into 665 * a growable stack region and the stack growth 666 * fails. It returns true if va was not within 667 * a growable stack region, or if the stack 668 * growth succeeded. 669 */ 670 if (!grow_stack (p, va)) { 671 rv = KERN_FAILURE; 672 --p->p_lock; 673 goto nogo; 674 } 675 676 /* Fault in the user page: */ 677 rv = vm_fault(map, va, ftype, 678 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 679 680 --p->p_lock; 681 } else { 682 /* 683 * Don't allow user-mode faults in kernel address space. 684 */ 685 if (usermode) 686 goto nogo; 687 688 /* 689 * Since we know that kernel virtual address addresses 690 * always have pte pages mapped, we just have to fault 691 * the page. 692 */ 693 rv = vm_fault(kernel_map, va, ftype, FALSE); 694 } 695 696 if (rv == KERN_SUCCESS) 697 return (0); 698nogo: 699 if (!usermode) { 700 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 701 frame->tf_eip = (int)curpcb->pcb_onfault; 702 return (0); 703 } 704 trap_fatal(frame, eva); 705 return (-1); 706 } 707 708 /* kludge to pass faulting virtual address to sendsig */ 709 frame->tf_err = eva; 710 711 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 712} 713#endif 714 715int 716trap_pfault(frame, usermode, eva) 717 struct trapframe *frame; 718 int usermode; 719 vm_offset_t eva; 720{ 721 vm_offset_t va; 722 struct vmspace *vm = NULL; 723 vm_map_t map = 0; 724 int rv = 0; 725 vm_prot_t ftype; 726 struct proc *p = curproc; 727 728 va = trunc_page(eva); 729 if (va >= KERNBASE) { 730 /* 731 * Don't allow user-mode faults in kernel address space. 732 * An exception: if the faulting address is the invalid 733 * instruction entry in the IDT, then the Intel Pentium 734 * F00F bug workaround was triggered, and we need to 735 * treat it is as an illegal instruction, and not a page 736 * fault. 737 */ 738#if defined(I586_CPU) && !defined(NO_F00F_HACK) 739 if ((eva == (unsigned int)&t_idt[6]) && has_f00f_bug) { 740 frame->tf_trapno = T_PRIVINFLT; 741 return -2; 742 } 743#endif 744 if (usermode) 745 goto nogo; 746 747 map = kernel_map; 748 } else { 749 /* 750 * This is a fault on non-kernel virtual memory. 751 * vm is initialized above to NULL. If curproc is NULL 752 * or curproc->p_vmspace is NULL the fault is fatal. 753 */ 754 if (p != NULL) 755 vm = p->p_vmspace; 756 757 if (vm == NULL) 758 goto nogo; 759 760 map = &vm->vm_map; 761 } 762 763 if (frame->tf_err & PGEX_W) 764 ftype = VM_PROT_READ | VM_PROT_WRITE; 765 else 766 ftype = VM_PROT_READ; 767 768 if (map != kernel_map) { 769 /* 770 * Keep swapout from messing with us during this 771 * critical time. 772 */ 773 ++p->p_lock; 774 775 /* 776 * Grow the stack if necessary 777 */ 778 /* grow_stack returns false only if va falls into 779 * a growable stack region and the stack growth 780 * fails. It returns true if va was not within 781 * a growable stack region, or if the stack 782 * growth succeeded. 783 */ 784 if (!grow_stack (p, va)) { 785 rv = KERN_FAILURE; 786 --p->p_lock; 787 goto nogo; 788 } 789 790 /* Fault in the user page: */ 791 rv = vm_fault(map, va, ftype, 792 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 793 794 --p->p_lock; 795 } else { 796 /* 797 * Don't have to worry about process locking or stacks in the kernel. 798 */ 799 rv = vm_fault(map, va, ftype, FALSE); 800 } 801 802 if (rv == KERN_SUCCESS) 803 return (0); 804nogo: 805 if (!usermode) { 806 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 807 frame->tf_eip = (int)curpcb->pcb_onfault; 808 return (0); 809 } 810 trap_fatal(frame, eva); 811 return (-1); 812 } 813 814 /* kludge to pass faulting virtual address to sendsig */ 815 frame->tf_err = eva; 816 817 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 818} 819 820static void 821trap_fatal(frame, eva) 822 struct trapframe *frame; 823 vm_offset_t eva; 824{ 825 int code, type, ss, esp; 826 struct soft_segment_descriptor softseg; 827 828 code = frame->tf_err; 829 type = frame->tf_trapno; 830 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 831 832 if (type <= MAX_TRAP_MSG) 833 printf("\n\nFatal trap %d: %s while in %s mode\n", 834 type, trap_msg[type], 835 frame->tf_eflags & PSL_VM ? "vm86" : 836 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 837#ifdef SMP 838 /* three seperate prints in case of a trap on an unmapped page */ 839 printf("mp_lock = %08x; ", mp_lock); 840 printf("cpuid = %d; ", cpuid); 841 printf("lapic.id = %08x\n", lapic.id); 842#endif 843 if (type == T_PAGEFLT) { 844 printf("fault virtual address = 0x%x\n", eva); 845 printf("fault code = %s %s, %s\n", 846 code & PGEX_U ? "user" : "supervisor", 847 code & PGEX_W ? "write" : "read", 848 code & PGEX_P ? "protection violation" : "page not present"); 849 } 850 printf("instruction pointer = 0x%x:0x%x\n", 851 frame->tf_cs & 0xffff, frame->tf_eip); 852 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 853 ss = frame->tf_ss & 0xffff; 854 esp = frame->tf_esp; 855 } else { 856 ss = GSEL(GDATA_SEL, SEL_KPL); 857 esp = (int)&frame->tf_esp; 858 } 859 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 860 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 861 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 862 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 863 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 864 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 865 softseg.ssd_gran); 866 printf("processor eflags = "); 867 if (frame->tf_eflags & PSL_T) 868 printf("trace trap, "); 869 if (frame->tf_eflags & PSL_I) 870 printf("interrupt enabled, "); 871 if (frame->tf_eflags & PSL_NT) 872 printf("nested task, "); 873 if (frame->tf_eflags & PSL_RF) 874 printf("resume, "); 875 if (frame->tf_eflags & PSL_VM) 876 printf("vm86, "); 877 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 878 printf("current process = "); 879 if (curproc) { 880 printf("%lu (%s)\n", 881 (u_long)curproc->p_pid, curproc->p_comm ? 882 curproc->p_comm : ""); 883 } else { 884 printf("Idle\n"); 885 } 886 printf("interrupt mask = "); 887 if ((cpl & net_imask) == net_imask) 888 printf("net "); 889 if ((cpl & tty_imask) == tty_imask) 890 printf("tty "); 891 if ((cpl & bio_imask) == bio_imask) 892 printf("bio "); 893 if ((cpl & cam_imask) == cam_imask) 894 printf("cam "); 895 if (cpl == 0) 896 printf("none"); 897#ifdef SMP 898/** 899 * XXX FIXME: 900 * we probably SHOULD have stopped the other CPUs before now! 901 * another CPU COULD have been touching cpl at this moment... 902 */ 903 printf(" <- SMP: XXX"); 904#endif 905 printf("\n"); 906 907#ifdef KDB 908 if (kdb_trap(&psl)) 909 return; 910#endif 911#ifdef DDB 912 if ((debugger_on_panic || in_Debugger) && kdb_trap(type, 0, frame)) 913 return; 914#endif 915 printf("trap number = %d\n", type); 916 if (type <= MAX_TRAP_MSG) 917 panic(trap_msg[type]); 918 else 919 panic("unknown/reserved trap"); 920} 921 922/* 923 * Double fault handler. Called when a fault occurs while writing 924 * a frame for a trap/exception onto the stack. This usually occurs 925 * when the stack overflows (such is the case with infinite recursion, 926 * for example). 927 * 928 * XXX Note that the current PTD gets replaced by IdlePTD when the 929 * task switch occurs. This means that the stack that was active at 930 * the time of the double fault is not available at <kstack> unless 931 * the machine was idle when the double fault occurred. The downside 932 * of this is that "trace <ebp>" in ddb won't work. 933 */ 934void 935dblfault_handler() 936{ 937 printf("\nFatal double fault:\n"); 938 printf("eip = 0x%x\n", common_tss.tss_eip); 939 printf("esp = 0x%x\n", common_tss.tss_esp); 940 printf("ebp = 0x%x\n", common_tss.tss_ebp); 941#ifdef SMP 942 /* three seperate prints in case of a trap on an unmapped page */ 943 printf("mp_lock = %08x; ", mp_lock); 944 printf("cpuid = %d; ", cpuid); 945 printf("lapic.id = %08x\n", lapic.id); 946#endif 947 panic("double fault"); 948} 949 950/* 951 * Compensate for 386 brain damage (missing URKR). 952 * This is a little simpler than the pagefault handler in trap() because 953 * it the page tables have already been faulted in and high addresses 954 * are thrown out early for other reasons. 955 */ 956int trapwrite(addr) 957 unsigned addr; 958{ 959 struct proc *p; 960 vm_offset_t va; 961 struct vmspace *vm; 962 int rv; 963 964 va = trunc_page((vm_offset_t)addr); 965 /* 966 * XXX - MAX is END. Changed > to >= for temp. fix. 967 */ 968 if (va >= VM_MAXUSER_ADDRESS) 969 return (1); 970 971 p = curproc; 972 vm = p->p_vmspace; 973 974 ++p->p_lock; 975 976 if (!grow_stack (p, va)) { 977 --p->p_lock; 978 return (1); 979 } 980 981 /* 982 * fault the data page 983 */ 984 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, VM_FAULT_DIRTY); 985 986 --p->p_lock; 987 988 if (rv != KERN_SUCCESS) 989 return 1; 990 991 return (0); 992} 993 994/* 995 * System call request from POSIX system call gate interface to kernel. 996 * Like trap(), argument is call by reference. 997 */ 998void 999syscall(frame) 1000 struct trapframe frame; 1001{ 1002 caddr_t params; 1003 int i; 1004 struct sysent *callp; 1005 struct proc *p = curproc; 1006 u_quad_t sticks; 1007 int error; 1008 int args[8]; 1009 u_int code; 1010 1011#ifdef DIAGNOSTIC 1012 if (ISPL(frame.tf_cs) != SEL_UPL) 1013 panic("syscall"); 1014#endif 1015 sticks = p->p_sticks; 1016 p->p_md.md_regs = &frame; 1017 params = (caddr_t)frame.tf_esp + sizeof(int); 1018 code = frame.tf_eax; 1019 if (p->p_sysent->sv_prepsyscall) { 1020 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); 1021 } else { 1022 /* 1023 * Need to check if this is a 32 bit or 64 bit syscall. 1024 */ 1025 if (code == SYS_syscall) { 1026 /* 1027 * Code is first argument, followed by actual args. 1028 */ 1029 code = fuword(params); 1030 params += sizeof(int); 1031 } else if (code == SYS___syscall) { 1032 /* 1033 * Like syscall, but code is a quad, so as to maintain 1034 * quad alignment for the rest of the arguments. 1035 */ 1036 code = fuword(params); 1037 params += sizeof(quad_t); 1038 } 1039 } 1040 1041 if (p->p_sysent->sv_mask) 1042 code &= p->p_sysent->sv_mask; 1043 1044 if (code >= p->p_sysent->sv_size) 1045 callp = &p->p_sysent->sv_table[0]; 1046 else 1047 callp = &p->p_sysent->sv_table[code]; 1048 1049 if (params && (i = callp->sy_narg * sizeof(int)) && 1050 (error = copyin(params, (caddr_t)args, (u_int)i))) { 1051#ifdef KTRACE 1052 if (KTRPOINT(p, KTR_SYSCALL)) 1053 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 1054#endif 1055 goto bad; 1056 } 1057#ifdef KTRACE 1058 if (KTRPOINT(p, KTR_SYSCALL)) 1059 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 1060#endif 1061 p->p_retval[0] = 0; 1062 p->p_retval[1] = frame.tf_edx; 1063 1064 STOPEVENT(p, S_SCE, callp->sy_narg); 1065 1066 error = (*callp->sy_call)(p, args); 1067 1068 switch (error) { 1069 1070 case 0: 1071 /* 1072 * Reinitialize proc pointer `p' as it may be different 1073 * if this is a child returning from fork syscall. 1074 */ 1075 p = curproc; 1076 frame.tf_eax = p->p_retval[0]; 1077 frame.tf_edx = p->p_retval[1]; 1078 frame.tf_eflags &= ~PSL_C; 1079 break; 1080 1081 case ERESTART: 1082 /* 1083 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 1084 * int 0x80 is 2 bytes. We saved this in tf_err. 1085 */ 1086 frame.tf_eip -= frame.tf_err; 1087 break; 1088 1089 case EJUSTRETURN: 1090 break; 1091 1092 default: 1093bad: 1094 if (p->p_sysent->sv_errsize) { 1095 if (error >= p->p_sysent->sv_errsize) 1096 error = -1; /* XXX */ 1097 else 1098 error = p->p_sysent->sv_errtbl[error]; 1099 } 1100 frame.tf_eax = error; 1101 frame.tf_eflags |= PSL_C; 1102 break; 1103 } 1104 1105 if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) { 1106 /* Traced syscall. */ 1107 frame.tf_eflags &= ~PSL_T; 1108 trapsignal(p, SIGTRAP, 0); 1109 } 1110 1111 userret(p, &frame, sticks); 1112 1113#ifdef KTRACE 1114 if (KTRPOINT(p, KTR_SYSRET)) 1115 ktrsysret(p->p_tracep, code, error, p->p_retval[0]); 1116#endif 1117 1118 /* 1119 * This works because errno is findable through the 1120 * register set. If we ever support an emulation where this 1121 * is not the case, this code will need to be revisited. 1122 */ 1123 STOPEVENT(p, S_SCX, code); 1124 1125} 1126 1127/* 1128 * Simplified back end of syscall(), used when returning from fork() 1129 * directly into user mode. 1130 */ 1131void 1132fork_return(p, frame) 1133 struct proc *p; 1134 struct trapframe frame; 1135{ 1136 frame.tf_eax = 0; /* Child returns zero */ 1137 frame.tf_eflags &= ~PSL_C; /* success */ 1138 frame.tf_edx = 1; 1139 1140 userret(p, &frame, 0); 1141#ifdef KTRACE 1142 if (KTRPOINT(p, KTR_SYSRET)) 1143 ktrsysret(p->p_tracep, SYS_fork, 0, 0); 1144#endif 1145} 1146