Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/trap.c
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1 /*- 2 * Copyright (C) 1994, David Greenman 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the University of Utah, and William Jolitz. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91 38 * $FreeBSD$ 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 #ifdef DDB 97 extern int in_Debugger, debugger_on_panic; 98 #endif 99 100 #include "isa.h" 101 #include "npx.h" 102 103 extern struct i386tss common_tss; 104 105 int (*pmath_emulate) __P((struct trapframe *)); 106 107 extern void trap __P((struct trapframe frame)); 108 extern int trapwrite __P((unsigned addr)); 109 extern void syscall __P((struct trapframe frame)); 110 111 static int trap_pfault __P((struct trapframe *, int, vm_offset_t)); 112 static void trap_fatal __P((struct trapframe *, vm_offset_t)); 113 void dblfault_handler __P((void)); 114 115 extern inthand_t IDTVEC(syscall); 116 117 #define MAX_TRAP_MSG 28 118 static char *trap_msg[] = { 119 "", /* 0 unused */ 120 "privileged instruction fault", /* 1 T_PRIVINFLT */ 121 "", /* 2 unused */ 122 "breakpoint instruction fault", /* 3 T_BPTFLT */ 123 "", /* 4 unused */ 124 "", /* 5 unused */ 125 "arithmetic trap", /* 6 T_ARITHTRAP */ 126 "system forced exception", /* 7 T_ASTFLT */ 127 "", /* 8 unused */ 128 "general protection fault", /* 9 T_PROTFLT */ 129 "trace trap", /* 10 T_TRCTRAP */ 130 "", /* 11 unused */ 131 "page fault", /* 12 T_PAGEFLT */ 132 "", /* 13 unused */ 133 "alignment fault", /* 14 T_ALIGNFLT */ 134 "", /* 15 unused */ 135 "", /* 16 unused */ 136 "", /* 17 unused */ 137 "integer divide fault", /* 18 T_DIVIDE */ 138 "non-maskable interrupt trap", /* 19 T_NMI */ 139 "overflow trap", /* 20 T_OFLOW */ 140 "FPU bounds check fault", /* 21 T_BOUND */ 141 "FPU device not available", /* 22 T_DNA */ 142 "double fault", /* 23 T_DOUBLEFLT */ 143 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 144 "invalid TSS fault", /* 25 T_TSSFLT */ 145 "segment not present fault", /* 26 T_SEGNPFLT */ 146 "stack fault", /* 27 T_STKFLT */ 147 "machine check trap", /* 28 T_MCHK */ 148 }; 149 150 static __inline void userret __P((struct proc *p, struct trapframe *frame, 151 u_quad_t oticks)); 152 153 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 154 extern struct gate_descriptor *t_idt; 155 extern int has_f00f_bug; 156 #endif 157 158 static __inline void 159 userret(p, frame, oticks) 160 struct proc *p; 161 struct trapframe *frame; 162 u_quad_t oticks; 163 { 164 int sig, s; 165 166 while ((sig = CURSIG(p)) != 0) 167 postsig(sig); 168 169 #if 0 170 if (!want_resched && 171 (p->p_priority <= p->p_usrpri) && 172 (p->p_rtprio.type == RTP_PRIO_NORMAL)) { 173 int newpriority; 174 p->p_estcpu += 1; 175 newpriority = PUSER + p->p_estcpu / 4 + 2 * p->p_nice; 176 newpriority = min(newpriority, MAXPRI); 177 p->p_usrpri = newpriority; 178 } 179 #endif 180 181 p->p_priority = p->p_usrpri; 182 if (want_resched) { 183 /* 184 * Since we are curproc, clock will normally just change 185 * our priority without moving us from one queue to another 186 * (since the running process is not on a queue.) 187 * If that happened after we setrunqueue ourselves but before we 188 * mi_switch()'ed, we might not be on the queue indicated by 189 * our priority. 190 */ 191 s = splhigh(); 192 setrunqueue(p); 193 p->p_stats->p_ru.ru_nivcsw++; 194 mi_switch(); 195 splx(s); 196 while ((sig = CURSIG(p)) != 0) 197 postsig(sig); 198 } 199 /* 200 * Charge system time if profiling. 201 */ 202 if (p->p_flag & P_PROFIL) 203 addupc_task(p, frame->tf_eip, 204 (u_int)(p->p_sticks - oticks) * psratio); 205 206 curpriority = p->p_priority; 207 } 208 209 /* 210 * Exception, fault, and trap interface to the FreeBSD kernel. 211 * This common code is called from assembly language IDT gate entry 212 * routines that prepare a suitable stack frame, and restore this 213 * frame after the exception has been processed. 214 */ 215 216 void 217 trap(frame) 218 struct trapframe frame; 219 { 220 struct proc *p = curproc; 221 u_quad_t sticks = 0; 222 int i = 0, ucode = 0, type, code; 223 vm_offset_t eva; 224 225 if (!(frame.tf_eflags & PSL_I)) { 226 /* 227 * Buggy application or kernel code has disabled interrupts 228 * and then trapped. Enabling interrupts now is wrong, but 229 * it is better than running with interrupts disabled until 230 * they are accidentally enabled later. 231 */ 232 type = frame.tf_trapno; 233 if (ISPL(frame.tf_cs) == SEL_UPL || (frame.tf_eflags & PSL_VM)) 234 printf( 235 "pid %ld (%s): trap %d with interrupts disabled\n", 236 (long)curproc->p_pid, curproc->p_comm, type); 237 else if (type != T_BPTFLT && type != T_TRCTRAP) 238 /* 239 * XXX not quite right, since this may be for a 240 * multiple fault in user mode. 241 */ 242 printf("kernel trap %d with interrupts disabled\n", 243 type); 244 enable_intr(); 245 } 246 247 eva = 0; 248 if (frame.tf_trapno == T_PAGEFLT) { 249 /* 250 * For some Cyrix CPUs, %cr2 is clobbered by interrupts. 251 * This problem is worked around by using an interrupt 252 * gate for the pagefault handler. We are finally ready 253 * to read %cr2 and then must reenable interrupts. 254 * 255 * XXX this should be in the switch statement, but the 256 * NO_FOOF_HACK and VM86 goto and ifdefs obfuscate the 257 * flow of control too much for this to be obviously 258 * correct. 259 */ 260 eva = rcr2(); 261 enable_intr(); 262 } 263 264 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 265 restart: 266 #endif 267 type = frame.tf_trapno; 268 code = frame.tf_err; 269 270 #ifdef VM86 271 if (in_vm86call) { 272 if (frame.tf_eflags & PSL_VM && 273 (type == T_PROTFLT || type == T_STKFLT)) { 274 i = vm86_emulate((struct vm86frame *)&frame); 275 if (i != 0) 276 /* 277 * returns to original process 278 */ 279 vm86_trap((struct vm86frame *)&frame); 280 return; 281 } 282 switch (type) { 283 /* 284 * these traps want either a process context, or 285 * assume a normal userspace trap. 286 */ 287 case T_PROTFLT: 288 case T_SEGNPFLT: 289 trap_fatal(&frame, eva); 290 return; 291 case T_TRCTRAP: 292 type = T_BPTFLT; /* kernel breakpoint */ 293 /* FALL THROUGH */ 294 } 295 goto kernel_trap; /* normal kernel trap handling */ 296 } 297 #endif 298 299 if ((ISPL(frame.tf_cs) == SEL_UPL) || (frame.tf_eflags & PSL_VM)) { 300 /* user trap */ 301 302 sticks = p->p_sticks; 303 p->p_md.md_regs = &frame; 304 305 switch (type) { 306 case T_PRIVINFLT: /* privileged instruction fault */ 307 ucode = type; 308 i = SIGILL; 309 break; 310 311 case T_BPTFLT: /* bpt instruction fault */ 312 case T_TRCTRAP: /* trace trap */ 313 frame.tf_eflags &= ~PSL_T; 314 i = SIGTRAP; 315 break; 316 317 case T_ARITHTRAP: /* arithmetic trap */ 318 ucode = code; 319 i = SIGFPE; 320 break; 321 322 case T_ASTFLT: /* Allow process switch */ 323 astoff(); 324 cnt.v_soft++; 325 if (p->p_flag & P_OWEUPC) { 326 p->p_flag &= ~P_OWEUPC; 327 addupc_task(p, p->p_stats->p_prof.pr_addr, 328 p->p_stats->p_prof.pr_ticks); 329 } 330 goto out; 331 332 /* 333 * The following two traps can happen in 334 * vm86 mode, and, if so, we want to handle 335 * them specially. 336 */ 337 case T_PROTFLT: /* general protection fault */ 338 case T_STKFLT: /* stack fault */ 339 #ifdef VM86 340 if (frame.tf_eflags & PSL_VM) { 341 i = vm86_emulate((struct vm86frame *)&frame); 342 if (i == 0) 343 goto out; 344 break; 345 } 346 #endif /* VM86 */ 347 /* FALL THROUGH */ 348 349 case T_SEGNPFLT: /* segment not present fault */ 350 case T_TSSFLT: /* invalid TSS fault */ 351 case T_DOUBLEFLT: /* double fault */ 352 default: 353 ucode = code + BUS_SEGM_FAULT ; 354 i = SIGBUS; 355 break; 356 357 case T_PAGEFLT: /* page fault */ 358 i = trap_pfault(&frame, TRUE, eva); 359 if (i == -1) 360 return; 361 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 362 if (i == -2) 363 goto restart; 364 #endif 365 if (i == 0) 366 goto out; 367 368 ucode = T_PAGEFLT; 369 break; 370 371 case T_DIVIDE: /* integer divide fault */ 372 ucode = FPE_INTDIV_TRAP; 373 i = SIGFPE; 374 break; 375 376 #if NISA > 0 377 case T_NMI: 378 #ifdef POWERFAIL_NMI 379 goto handle_powerfail; 380 #else /* !POWERFAIL_NMI */ 381 #ifdef DDB 382 /* NMI can be hooked up to a pushbutton for debugging */ 383 printf ("NMI ... going to debugger\n"); 384 if (kdb_trap (type, 0, &frame)) 385 return; 386 #endif /* DDB */ 387 /* machine/parity/power fail/"kitchen sink" faults */ 388 if (isa_nmi(code) == 0) return; 389 panic("NMI indicates hardware failure"); 390 #endif /* POWERFAIL_NMI */ 391 #endif /* NISA > 0 */ 392 393 case T_OFLOW: /* integer overflow fault */ 394 ucode = FPE_INTOVF_TRAP; 395 i = SIGFPE; 396 break; 397 398 case T_BOUND: /* bounds check fault */ 399 ucode = FPE_SUBRNG_TRAP; 400 i = SIGFPE; 401 break; 402 403 case T_DNA: 404 #if NNPX > 0 405 /* if a transparent fault (due to context switch "late") */ 406 if (npxdna()) 407 return; 408 #endif 409 if (!pmath_emulate) { 410 i = SIGFPE; 411 ucode = FPE_FPU_NP_TRAP; 412 break; 413 } 414 i = (*pmath_emulate)(&frame); 415 if (i == 0) { 416 if (!(frame.tf_eflags & PSL_T)) 417 return; 418 frame.tf_eflags &= ~PSL_T; 419 i = SIGTRAP; 420 } 421 /* else ucode = emulator_only_knows() XXX */ 422 break; 423 424 case T_FPOPFLT: /* FPU operand fetch fault */ 425 ucode = T_FPOPFLT; 426 i = SIGILL; 427 break; 428 } 429 } else { 430 #ifdef VM86 431 kernel_trap: 432 #endif 433 /* kernel trap */ 434 435 switch (type) { 436 case T_PAGEFLT: /* page fault */ 437 (void) trap_pfault(&frame, FALSE, eva); 438 return; 439 440 case T_DNA: 441 #if NNPX > 0 442 /* 443 * The kernel is apparently using npx for copying. 444 * XXX this should be fatal unless the kernel has 445 * registered such use. 446 */ 447 if (npxdna()) 448 return; 449 #endif 450 break; 451 452 case T_PROTFLT: /* general protection fault */ 453 case T_SEGNPFLT: /* segment not present fault */ 454 /* 455 * Invalid segment selectors and out of bounds 456 * %eip's and %esp's can be set up in user mode. 457 * This causes a fault in kernel mode when the 458 * kernel tries to return to user mode. We want 459 * to get this fault so that we can fix the 460 * problem here and not have to check all the 461 * selectors and pointers when the user changes 462 * them. 463 */ 464 #define MAYBE_DORETI_FAULT(where, whereto) \ 465 do { \ 466 if (frame.tf_eip == (int)where) { \ 467 frame.tf_eip = (int)whereto; \ 468 return; \ 469 } \ 470 } while (0) 471 472 if (intr_nesting_level == 0) { 473 /* 474 * Invalid %fs's and %gs's can be created using 475 * procfs or PT_SETREGS or by invalidating the 476 * underlying LDT entry. This causes a fault 477 * in kernel mode when the kernel attempts to 478 * switch contexts. Lose the bad context 479 * (XXX) so that we can continue, and generate 480 * a signal. 481 */ 482 if (frame.tf_eip == (int)cpu_switch_load_fs) { 483 curpcb->pcb_fs = 0; 484 psignal(p, SIGBUS); 485 return; 486 } 487 if (frame.tf_eip == (int)cpu_switch_load_gs) { 488 curpcb->pcb_gs = 0; 489 psignal(p, SIGBUS); 490 return; 491 } 492 MAYBE_DORETI_FAULT(doreti_iret, 493 doreti_iret_fault); 494 MAYBE_DORETI_FAULT(doreti_popl_ds, 495 doreti_popl_ds_fault); 496 MAYBE_DORETI_FAULT(doreti_popl_es, 497 doreti_popl_es_fault); 498 if (curpcb && curpcb->pcb_onfault) { 499 frame.tf_eip = (int)curpcb->pcb_onfault; 500 return; 501 } 502 } 503 break; 504 505 case T_TSSFLT: 506 /* 507 * PSL_NT can be set in user mode and isn't cleared 508 * automatically when the kernel is entered. This 509 * causes a TSS fault when the kernel attempts to 510 * `iret' because the TSS link is uninitialized. We 511 * want to get this fault so that we can fix the 512 * problem here and not every time the kernel is 513 * entered. 514 */ 515 if (frame.tf_eflags & PSL_NT) { 516 frame.tf_eflags &= ~PSL_NT; 517 return; 518 } 519 break; 520 521 case T_TRCTRAP: /* trace trap */ 522 if (frame.tf_eip == (int)IDTVEC(syscall)) { 523 /* 524 * We've just entered system mode via the 525 * syscall lcall. Continue single stepping 526 * silently until the syscall handler has 527 * saved the flags. 528 */ 529 return; 530 } 531 if (frame.tf_eip == (int)IDTVEC(syscall) + 1) { 532 /* 533 * The syscall handler has now saved the 534 * flags. Stop single stepping it. 535 */ 536 frame.tf_eflags &= ~PSL_T; 537 return; 538 } 539 /* 540 * Fall through. 541 */ 542 case T_BPTFLT: 543 /* 544 * If DDB is enabled, let it handle the debugger trap. 545 * Otherwise, debugger traps "can't happen". 546 */ 547 #ifdef DDB 548 if (kdb_trap (type, 0, &frame)) 549 return; 550 #endif 551 break; 552 553 #if NISA > 0 554 case T_NMI: 555 #ifdef POWERFAIL_NMI 556 #ifndef TIMER_FREQ 557 # define TIMER_FREQ 1193182 558 #endif 559 handle_powerfail: 560 { 561 static unsigned lastalert = 0; 562 563 if(time_second - lastalert > 10) 564 { 565 log(LOG_WARNING, "NMI: power fail\n"); 566 sysbeep(TIMER_FREQ/880, hz); 567 lastalert = time_second; 568 } 569 return; 570 } 571 #else /* !POWERFAIL_NMI */ 572 #ifdef DDB 573 /* NMI can be hooked up to a pushbutton for debugging */ 574 printf ("NMI ... going to debugger\n"); 575 if (kdb_trap (type, 0, &frame)) 576 return; 577 #endif /* DDB */ 578 /* machine/parity/power fail/"kitchen sink" faults */ 579 if (isa_nmi(code) == 0) return; 580 /* FALL THROUGH */ 581 #endif /* POWERFAIL_NMI */ 582 #endif /* NISA > 0 */ 583 } 584 585 trap_fatal(&frame, eva); 586 return; 587 } 588 589 /* Translate fault for emulators (e.g. Linux) */ 590 if (*p->p_sysent->sv_transtrap) 591 i = (*p->p_sysent->sv_transtrap)(i, type); 592 593 trapsignal(p, i, ucode); 594 595 #ifdef DEBUG 596 if (type <= MAX_TRAP_MSG) { 597 uprintf("fatal process exception: %s", 598 trap_msg[type]); 599 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 600 uprintf(", fault VA = 0x%lx", (u_long)eva); 601 uprintf("\n"); 602 } 603 #endif 604 605 out: 606 userret(p, &frame, sticks); 607 } 608 609 #ifdef notyet 610 /* 611 * This version doesn't allow a page fault to user space while 612 * in the kernel. The rest of the kernel needs to be made "safe" 613 * before this can be used. I think the only things remaining 614 * to be made safe are the iBCS2 code and the process tracing/ 615 * debugging code. 616 */ 617 static int 618 trap_pfault(frame, usermode, eva) 619 struct trapframe *frame; 620 int usermode; 621 vm_offset_t eva; 622 { 623 vm_offset_t va; 624 struct vmspace *vm = NULL; 625 vm_map_t map = 0; 626 int rv = 0; 627 vm_prot_t ftype; 628 struct proc *p = curproc; 629 630 if (frame->tf_err & PGEX_W) 631 ftype = VM_PROT_READ | VM_PROT_WRITE; 632 else 633 ftype = VM_PROT_READ; 634 635 va = trunc_page(eva); 636 if (va < VM_MIN_KERNEL_ADDRESS) { 637 vm_offset_t v; 638 vm_page_t mpte; 639 640 if (p == NULL || 641 (!usermode && va < VM_MAXUSER_ADDRESS && 642 (intr_nesting_level != 0 || curpcb == NULL || 643 curpcb->pcb_onfault == NULL))) { 644 trap_fatal(frame, eva); 645 return (-1); 646 } 647 648 /* 649 * This is a fault on non-kernel virtual memory. 650 * vm is initialized above to NULL. If curproc is NULL 651 * or curproc->p_vmspace is NULL the fault is fatal. 652 */ 653 vm = p->p_vmspace; 654 if (vm == NULL) 655 goto nogo; 656 657 map = &vm->vm_map; 658 659 /* 660 * Keep swapout from messing with us during this 661 * critical time. 662 */ 663 ++p->p_lock; 664 665 /* 666 * Grow the stack if necessary 667 */ 668 #ifndef VM_STACK 669 if ((caddr_t)va > vm->vm_maxsaddr && va < USRSTACK) { 670 if (!grow(p, va)) { 671 rv = KERN_FAILURE; 672 --p->p_lock; 673 goto nogo; 674 } 675 } 676 677 #else 678 /* grow_stack returns false only if va falls into 679 * a growable stack region and the stack growth 680 * fails. It returns true if va was not within 681 * a growable stack region, or if the stack 682 * growth succeeded. 683 */ 684 if (!grow_stack (p, va)) { 685 rv = KERN_FAILURE; 686 --p->p_lock; 687 goto nogo; 688 } 689 #endif 690 691 /* Fault in the user page: */ 692 rv = vm_fault(map, va, ftype, 693 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 694 695 --p->p_lock; 696 } else { 697 /* 698 * Don't allow user-mode faults in kernel address space. 699 */ 700 if (usermode) 701 goto nogo; 702 703 /* 704 * Since we know that kernel virtual address addresses 705 * always have pte pages mapped, we just have to fault 706 * the page. 707 */ 708 rv = vm_fault(kernel_map, va, ftype, FALSE); 709 } 710 711 if (rv == KERN_SUCCESS) 712 return (0); 713 nogo: 714 if (!usermode) { 715 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 716 frame->tf_eip = (int)curpcb->pcb_onfault; 717 return (0); 718 } 719 trap_fatal(frame, eva); 720 return (-1); 721 } 722 723 /* kludge to pass faulting virtual address to sendsig */ 724 frame->tf_err = eva; 725 726 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 727 } 728 #endif 729 730 int 731 trap_pfault(frame, usermode, eva) 732 struct trapframe *frame; 733 int usermode; 734 vm_offset_t eva; 735 { 736 vm_offset_t va; 737 struct vmspace *vm = NULL; 738 vm_map_t map = 0; 739 int rv = 0; 740 vm_prot_t ftype; 741 struct proc *p = curproc; 742 743 va = trunc_page(eva); 744 if (va >= KERNBASE) { 745 /* 746 * Don't allow user-mode faults in kernel address space. 747 * An exception: if the faulting address is the invalid 748 * instruction entry in the IDT, then the Intel Pentium 749 * F00F bug workaround was triggered, and we need to 750 * treat it is as an illegal instruction, and not a page 751 * fault. 752 */ 753 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 754 if ((eva == (unsigned int)&t_idt[6]) && has_f00f_bug) { 755 frame->tf_trapno = T_PRIVINFLT; 756 return -2; 757 } 758 #endif 759 if (usermode) 760 goto nogo; 761 762 map = kernel_map; 763 } else { 764 /* 765 * This is a fault on non-kernel virtual memory. 766 * vm is initialized above to NULL. If curproc is NULL 767 * or curproc->p_vmspace is NULL the fault is fatal. 768 */ 769 if (p != NULL) 770 vm = p->p_vmspace; 771 772 if (vm == NULL) 773 goto nogo; 774 775 map = &vm->vm_map; 776 } 777 778 if (frame->tf_err & PGEX_W) 779 ftype = VM_PROT_READ | VM_PROT_WRITE; 780 else 781 ftype = VM_PROT_READ; 782 783 if (map != kernel_map) { 784 /* 785 * Keep swapout from messing with us during this 786 * critical time. 787 */ 788 ++p->p_lock; 789 790 /* 791 * Grow the stack if necessary 792 */ 793 #ifndef VM_STACK 794 if ((caddr_t)va > vm->vm_maxsaddr && va < USRSTACK) { 795 if (!grow(p, va)) { 796 rv = KERN_FAILURE; 797 --p->p_lock; 798 goto nogo; 799 } 800 } 801 #else 802 /* grow_stack returns false only if va falls into 803 * a growable stack region and the stack growth 804 * fails. It returns true if va was not within 805 * a growable stack region, or if the stack 806 * growth succeeded. 807 */ 808 if (!grow_stack (p, va)) { 809 rv = KERN_FAILURE; 810 --p->p_lock; 811 goto nogo; 812 } 813 #endif 814 815 /* Fault in the user page: */ 816 rv = vm_fault(map, va, ftype, 817 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 818 819 --p->p_lock; 820 } else { 821 /* 822 * Don't have to worry about process locking or stacks in the kernel. 823 */ 824 rv = vm_fault(map, va, ftype, FALSE); 825 } 826 827 if (rv == KERN_SUCCESS) 828 return (0); 829 nogo: 830 if (!usermode) { 831 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 832 frame->tf_eip = (int)curpcb->pcb_onfault; 833 return (0); 834 } 835 trap_fatal(frame, eva); 836 return (-1); 837 } 838 839 /* kludge to pass faulting virtual address to sendsig */ 840 frame->tf_err = eva; 841 842 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 843 } 844 845 static void 846 trap_fatal(frame, eva) 847 struct trapframe *frame; 848 vm_offset_t eva; 849 { 850 int code, type, ss, esp; 851 struct soft_segment_descriptor softseg; 852 853 code = frame->tf_err; 854 type = frame->tf_trapno; 855 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 856 857 if (type <= MAX_TRAP_MSG) 858 printf("\n\nFatal trap %d: %s while in %s mode\n", 859 type, trap_msg[type], 860 frame->tf_eflags & PSL_VM ? "vm86" : 861 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 862 #ifdef SMP 863 /* three seperate prints in case of a trap on an unmapped page */ 864 printf("mp_lock = %08x; ", mp_lock); 865 printf("cpuid = %d; ", cpuid); 866 printf("lapic.id = %08x\n", lapic.id); 867 #endif 868 if (type == T_PAGEFLT) { 869 printf("fault virtual address = 0x%x\n", eva); 870 printf("fault code = %s %s, %s\n", 871 code & PGEX_U ? "user" : "supervisor", 872 code & PGEX_W ? "write" : "read", 873 code & PGEX_P ? "protection violation" : "page not present"); 874 } 875 printf("instruction pointer = 0x%x:0x%x\n", 876 frame->tf_cs & 0xffff, frame->tf_eip); 877 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 878 ss = frame->tf_ss & 0xffff; 879 esp = frame->tf_esp; 880 } else { 881 ss = GSEL(GDATA_SEL, SEL_KPL); 882 esp = (int)&frame->tf_esp; 883 } 884 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 885 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 886 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 887 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 888 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 889 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 890 softseg.ssd_gran); 891 printf("processor eflags = "); 892 if (frame->tf_eflags & PSL_T) 893 printf("trace trap, "); 894 if (frame->tf_eflags & PSL_I) 895 printf("interrupt enabled, "); 896 if (frame->tf_eflags & PSL_NT) 897 printf("nested task, "); 898 if (frame->tf_eflags & PSL_RF) 899 printf("resume, "); 900 if (frame->tf_eflags & PSL_VM) 901 printf("vm86, "); 902 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 903 printf("current process = "); 904 if (curproc) { 905 printf("%lu (%s)\n", 906 (u_long)curproc->p_pid, curproc->p_comm ? 907 curproc->p_comm : ""); 908 } else { 909 printf("Idle\n"); 910 } 911 printf("interrupt mask = "); 912 if ((cpl & net_imask) == net_imask) 913 printf("net "); 914 if ((cpl & tty_imask) == tty_imask) 915 printf("tty "); 916 if ((cpl & bio_imask) == bio_imask) 917 printf("bio "); 918 if ((cpl & cam_imask) == cam_imask) 919 printf("cam "); 920 if (cpl == 0) 921 printf("none"); 922 #ifdef SMP 923 /** 924 * XXX FIXME: 925 * we probably SHOULD have stopped the other CPUs before now! 926 * another CPU COULD have been touching cpl at this moment... 927 */ 928 printf(" <- SMP: XXX"); 929 #endif 930 printf("\n"); 931 932 #ifdef KDB 933 if (kdb_trap(&psl)) 934 return; 935 #endif 936 #ifdef DDB 937 if ((debugger_on_panic || in_Debugger) && kdb_trap(type, 0, frame)) 938 return; 939 #endif 940 printf("trap number = %d\n", type); 941 if (type <= MAX_TRAP_MSG) 942 panic(trap_msg[type]); 943 else 944 panic("unknown/reserved trap"); 945 } 946 947 /* 948 * Double fault handler. Called when a fault occurs while writing 949 * a frame for a trap/exception onto the stack. This usually occurs 950 * when the stack overflows (such is the case with infinite recursion, 951 * for example). 952 * 953 * XXX Note that the current PTD gets replaced by IdlePTD when the 954 * task switch occurs. This means that the stack that was active at 955 * the time of the double fault is not available at <kstack> unless 956 * the machine was idle when the double fault occurred. The downside 957 * of this is that "trace <ebp>" in ddb won't work. 958 */ 959 void 960 dblfault_handler() 961 { 962 printf("\nFatal double fault:\n"); 963 printf("eip = 0x%x\n", common_tss.tss_eip); 964 printf("esp = 0x%x\n", common_tss.tss_esp); 965 printf("ebp = 0x%x\n", common_tss.tss_ebp); 966 #ifdef SMP 967 /* three seperate prints in case of a trap on an unmapped page */ 968 printf("mp_lock = %08x; ", mp_lock); 969 printf("cpuid = %d; ", cpuid); 970 printf("lapic.id = %08x\n", lapic.id); 971 #endif 972 panic("double fault"); 973 } 974 975 /* 976 * Compensate for 386 brain damage (missing URKR). 977 * This is a little simpler than the pagefault handler in trap() because 978 * it the page tables have already been faulted in and high addresses 979 * are thrown out early for other reasons. 980 */ 981 int trapwrite(addr) 982 unsigned addr; 983 { 984 struct proc *p; 985 vm_offset_t va; 986 struct vmspace *vm; 987 int rv; 988 989 va = trunc_page((vm_offset_t)addr); 990 /* 991 * XXX - MAX is END. Changed > to >= for temp. fix. 992 */ 993 if (va >= VM_MAXUSER_ADDRESS) 994 return (1); 995 996 p = curproc; 997 vm = p->p_vmspace; 998 999 ++p->p_lock; 1000 1001 #ifndef VM_STACK 1002 if ((caddr_t)va >= vm->vm_maxsaddr && va < USRSTACK) { 1003 if (!grow(p, va)) { 1004 --p->p_lock; 1005 return (1); 1006 } 1007 } 1008 #else 1009 if (!grow_stack (p, va)) { 1010 --p->p_lock; 1011 return (1); 1012 } 1013 #endif 1014 1015 /* 1016 * fault the data page 1017 */ 1018 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, VM_FAULT_DIRTY); 1019 1020 --p->p_lock; 1021 1022 if (rv != KERN_SUCCESS) 1023 return 1; 1024 1025 return (0); 1026 } 1027 1028 /* 1029 * System call request from POSIX system call gate interface to kernel. 1030 * Like trap(), argument is call by reference. 1031 */ 1032 void 1033 syscall(frame) 1034 struct trapframe frame; 1035 { 1036 caddr_t params; 1037 int i; 1038 struct sysent *callp; 1039 struct proc *p = curproc; 1040 u_quad_t sticks; 1041 int error; 1042 int args[8]; 1043 u_int code; 1044 1045 #ifdef DIAGNOSTIC 1046 if (ISPL(frame.tf_cs) != SEL_UPL) 1047 panic("syscall"); 1048 #endif 1049 sticks = p->p_sticks; 1050 p->p_md.md_regs = &frame; 1051 params = (caddr_t)frame.tf_esp + sizeof(int); 1052 code = frame.tf_eax; 1053 if (p->p_sysent->sv_prepsyscall) { 1054 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); 1055 } else { 1056 /* 1057 * Need to check if this is a 32 bit or 64 bit syscall. 1058 */ 1059 if (code == SYS_syscall) { 1060 /* 1061 * Code is first argument, followed by actual args. 1062 */ 1063 code = fuword(params); 1064 params += sizeof(int); 1065 } else if (code == SYS___syscall) { 1066 /* 1067 * Like syscall, but code is a quad, so as to maintain 1068 * quad alignment for the rest of the arguments. 1069 */ 1070 code = fuword(params); 1071 params += sizeof(quad_t); 1072 } 1073 } 1074 1075 if (p->p_sysent->sv_mask) 1076 code &= p->p_sysent->sv_mask; 1077 1078 if (code >= p->p_sysent->sv_size) 1079 callp = &p->p_sysent->sv_table[0]; 1080 else 1081 callp = &p->p_sysent->sv_table[code]; 1082 1083 if (params && (i = callp->sy_narg * sizeof(int)) && 1084 (error = copyin(params, (caddr_t)args, (u_int)i))) { 1085 #ifdef KTRACE 1086 if (KTRPOINT(p, KTR_SYSCALL)) 1087 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 1088 #endif 1089 goto bad; 1090 } 1091 #ifdef KTRACE 1092 if (KTRPOINT(p, KTR_SYSCALL)) 1093 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 1094 #endif 1095 p->p_retval[0] = 0; 1096 p->p_retval[1] = frame.tf_edx; 1097 1098 STOPEVENT(p, S_SCE, callp->sy_narg); 1099 1100 error = (*callp->sy_call)(p, args); 1101 1102 switch (error) { 1103 1104 case 0: 1105 /* 1106 * Reinitialize proc pointer `p' as it may be different 1107 * if this is a child returning from fork syscall. 1108 */ 1109 p = curproc; 1110 frame.tf_eax = p->p_retval[0]; 1111 frame.tf_edx = p->p_retval[1]; 1112 frame.tf_eflags &= ~PSL_C; 1113 break; 1114 1115 case ERESTART: 1116 /* 1117 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 1118 * int 0x80 is 2 bytes. We saved this in tf_err. 1119 */ 1120 frame.tf_eip -= frame.tf_err; 1121 break; 1122 1123 case EJUSTRETURN: 1124 break; 1125 1126 default: 1127 bad: 1128 if (p->p_sysent->sv_errsize) 1129 if (error >= p->p_sysent->sv_errsize) 1130 error = -1; /* XXX */ 1131 else 1132 error = p->p_sysent->sv_errtbl[error]; 1133 frame.tf_eax = error; 1134 frame.tf_eflags |= PSL_C; 1135 break; 1136 } 1137 1138 if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) { 1139 /* Traced syscall. */ 1140 frame.tf_eflags &= ~PSL_T; 1141 trapsignal(p, SIGTRAP, 0); 1142 } 1143 1144 userret(p, &frame, sticks); 1145 1146 #ifdef KTRACE 1147 if (KTRPOINT(p, KTR_SYSRET)) 1148 ktrsysret(p->p_tracep, code, error, p->p_retval[0]); 1149 #endif 1150 1151 /* 1152 * This works because errno is findable through the 1153 * register set. If we ever support an emulation where this 1154 * is not the case, this code will need to be revisited. 1155 */ 1156 STOPEVENT(p, S_SCX, code); 1157 1158 } 1159 1160 /* 1161 * Simplified back end of syscall(), used when returning from fork() 1162 * directly into user mode. 1163 */ 1164 void 1165 fork_return(p, frame) 1166 struct proc *p; 1167 struct trapframe frame; 1168 { 1169 frame.tf_eax = 0; /* Child returns zero */ 1170 frame.tf_eflags &= ~PSL_C; /* success */ 1171 frame.tf_edx = 1; 1172 1173 userret(p, &frame, 0); 1174 #ifdef KTRACE 1175 if (KTRPOINT(p, KTR_SYSRET)) 1176 ktrsysret(p->p_tracep, SYS_fork, 0, 0); 1177 #endif 1178 }
Cache object: d803135cf64778662398fe00da97a983
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