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 1.138 1999/06/01 18:19:47 jlemon 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 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 #include <machine/vm86.h> 93 94 #ifdef DDB 95 extern int in_Debugger, debugger_on_panic; 96 #endif 97 98 #include "isa.h" 99 #include "npx.h" 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, vm_offset_t)); 108 static void trap_fatal __P((struct trapframe *, vm_offset_t)); 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 int has_f00f_bug; 151 #endif 152 153 static __inline void 154 userret(p, frame, oticks) 155 struct proc *p; 156 struct trapframe *frame; 157 u_quad_t oticks; 158 { 159 int sig, s; 160 161 while ((sig = CURSIG(p)) != 0) 162 postsig(sig); 163 164 #if 0 165 if (!want_resched && 166 (p->p_priority <= p->p_usrpri) && 167 (p->p_rtprio.type == RTP_PRIO_NORMAL)) { 168 int newpriority; 169 p->p_estcpu += 1; 170 newpriority = PUSER + p->p_estcpu / 4 + 2 * p->p_nice; 171 newpriority = min(newpriority, MAXPRI); 172 p->p_usrpri = newpriority; 173 } 174 #endif 175 176 p->p_priority = p->p_usrpri; 177 if (want_resched) { 178 /* 179 * Since we are curproc, clock will normally just change 180 * our priority without moving us from one queue to another 181 * (since the running process is not on a queue.) 182 * If that happened after we setrunqueue ourselves but before we 183 * mi_switch()'ed, we might not be on the queue indicated by 184 * our priority. 185 */ 186 s = splhigh(); 187 setrunqueue(p); 188 p->p_stats->p_ru.ru_nivcsw++; 189 mi_switch(); 190 splx(s); 191 while ((sig = CURSIG(p)) != 0) 192 postsig(sig); 193 } 194 /* 195 * Charge system time if profiling. 196 */ 197 if (p->p_flag & P_PROFIL) 198 addupc_task(p, frame->tf_eip, 199 (u_int)(p->p_sticks - oticks) * psratio); 200 201 curpriority = p->p_priority; 202 } 203 204 /* 205 * Exception, fault, and trap interface to the FreeBSD kernel. 206 * This common code is called from assembly language IDT gate entry 207 * routines that prepare a suitable stack frame, and restore this 208 * frame after the exception has been processed. 209 */ 210 211 void 212 trap(frame) 213 struct trapframe frame; 214 { 215 struct proc *p = curproc; 216 u_quad_t sticks = 0; 217 int i = 0, ucode = 0, type, code; 218 vm_offset_t eva; 219 220 if (!(frame.tf_eflags & PSL_I)) { 221 /* 222 * Buggy application or kernel code has disabled interrupts 223 * and then trapped. Enabling interrupts now is wrong, but 224 * it is better than running with interrupts disabled until 225 * they are accidentally enabled later. 226 */ 227 type = frame.tf_trapno; 228 if (ISPL(frame.tf_cs) == SEL_UPL || (frame.tf_eflags & PSL_VM)) 229 printf( 230 "pid %ld (%s): trap %d with interrupts disabled\n", 231 (long)curproc->p_pid, curproc->p_comm, type); 232 else if (type != T_BPTFLT && type != T_TRCTRAP) 233 /* 234 * XXX not quite right, since this may be for a 235 * multiple fault in user mode. 236 */ 237 printf("kernel trap %d with interrupts disabled\n", 238 type); 239 enable_intr(); 240 } 241 242 eva = 0; 243 if (frame.tf_trapno == T_PAGEFLT) { 244 /* 245 * For some Cyrix CPUs, %cr2 is clobbered by interrupts. 246 * This problem is worked around by using an interrupt 247 * gate for the pagefault handler. We are finally ready 248 * to read %cr2 and then must reenable interrupts. 249 * 250 * XXX this should be in the switch statement, but the 251 * NO_FOOF_HACK and VM86 goto and ifdefs obfuscate the 252 * flow of control too much for this to be obviously 253 * correct. 254 */ 255 eva = rcr2(); 256 enable_intr(); 257 } 258 259 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 260 restart: 261 #endif 262 type = frame.tf_trapno; 263 code = frame.tf_err; 264 265 if (in_vm86call) { 266 if (frame.tf_eflags & PSL_VM && 267 (type == T_PROTFLT || type == T_STKFLT)) { 268 i = vm86_emulate((struct vm86frame *)&frame); 269 if (i != 0) 270 /* 271 * returns to original process 272 */ 273 vm86_trap((struct vm86frame *)&frame); 274 return; 275 } 276 switch (type) { 277 /* 278 * these traps want either a process context, or 279 * assume a normal userspace trap. 280 */ 281 case T_PROTFLT: 282 case T_SEGNPFLT: 283 trap_fatal(&frame, eva); 284 return; 285 case T_TRCTRAP: 286 type = T_BPTFLT; /* kernel breakpoint */ 287 /* FALL THROUGH */ 288 } 289 goto kernel_trap; /* normal kernel trap handling */ 290 } 291 292 if ((ISPL(frame.tf_cs) == SEL_UPL) || (frame.tf_eflags & PSL_VM)) { 293 /* user trap */ 294 295 sticks = p->p_sticks; 296 p->p_md.md_regs = &frame; 297 298 switch (type) { 299 case T_PRIVINFLT: /* privileged instruction fault */ 300 ucode = type; 301 i = SIGILL; 302 break; 303 304 case T_BPTFLT: /* bpt instruction fault */ 305 case T_TRCTRAP: /* trace trap */ 306 frame.tf_eflags &= ~PSL_T; 307 i = SIGTRAP; 308 break; 309 310 case T_ARITHTRAP: /* arithmetic trap */ 311 ucode = code; 312 i = SIGFPE; 313 break; 314 315 case T_ASTFLT: /* Allow process switch */ 316 astoff(); 317 cnt.v_soft++; 318 if (p->p_flag & P_OWEUPC) { 319 p->p_flag &= ~P_OWEUPC; 320 addupc_task(p, p->p_stats->p_prof.pr_addr, 321 p->p_stats->p_prof.pr_ticks); 322 } 323 goto out; 324 325 /* 326 * The following two traps can happen in 327 * vm86 mode, and, if so, we want to handle 328 * them specially. 329 */ 330 case T_PROTFLT: /* general protection fault */ 331 case T_STKFLT: /* stack fault */ 332 if (frame.tf_eflags & PSL_VM) { 333 i = vm86_emulate((struct vm86frame *)&frame); 334 if (i == 0) 335 goto out; 336 break; 337 } 338 /* FALL THROUGH */ 339 340 case T_SEGNPFLT: /* segment not present fault */ 341 case T_TSSFLT: /* invalid TSS fault */ 342 case T_DOUBLEFLT: /* double fault */ 343 default: 344 ucode = code + BUS_SEGM_FAULT ; 345 i = SIGBUS; 346 break; 347 348 case T_PAGEFLT: /* page fault */ 349 i = trap_pfault(&frame, TRUE, eva); 350 if (i == -1) 351 return; 352 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 353 if (i == -2) 354 goto restart; 355 #endif 356 if (i == 0) 357 goto out; 358 359 ucode = T_PAGEFLT; 360 break; 361 362 case T_DIVIDE: /* integer divide fault */ 363 ucode = FPE_INTDIV_TRAP; 364 i = SIGFPE; 365 break; 366 367 #if NISA > 0 368 case T_NMI: 369 #ifdef POWERFAIL_NMI 370 goto handle_powerfail; 371 #else /* !POWERFAIL_NMI */ 372 #ifdef DDB 373 /* NMI can be hooked up to a pushbutton for debugging */ 374 printf ("NMI ... going to debugger\n"); 375 if (kdb_trap (type, 0, &frame)) 376 return; 377 #endif /* DDB */ 378 /* machine/parity/power fail/"kitchen sink" faults */ 379 if (isa_nmi(code) == 0) return; 380 panic("NMI indicates hardware failure"); 381 #endif /* POWERFAIL_NMI */ 382 #endif /* NISA > 0 */ 383 384 case T_OFLOW: /* integer overflow fault */ 385 ucode = FPE_INTOVF_TRAP; 386 i = SIGFPE; 387 break; 388 389 case T_BOUND: /* bounds check fault */ 390 ucode = FPE_SUBRNG_TRAP; 391 i = SIGFPE; 392 break; 393 394 case T_DNA: 395 #if NNPX > 0 396 /* if a transparent fault (due to context switch "late") */ 397 if (npxdna()) 398 return; 399 #endif 400 if (!pmath_emulate) { 401 i = SIGFPE; 402 ucode = FPE_FPU_NP_TRAP; 403 break; 404 } 405 i = (*pmath_emulate)(&frame); 406 if (i == 0) { 407 if (!(frame.tf_eflags & PSL_T)) 408 return; 409 frame.tf_eflags &= ~PSL_T; 410 i = SIGTRAP; 411 } 412 /* else ucode = emulator_only_knows() XXX */ 413 break; 414 415 case T_FPOPFLT: /* FPU operand fetch fault */ 416 ucode = T_FPOPFLT; 417 i = SIGILL; 418 break; 419 } 420 } else { 421 kernel_trap: 422 /* kernel trap */ 423 424 switch (type) { 425 case T_PAGEFLT: /* page fault */ 426 (void) trap_pfault(&frame, FALSE, eva); 427 return; 428 429 case T_DNA: 430 #if NNPX > 0 431 /* 432 * The kernel is apparently using npx for copying. 433 * XXX this should be fatal unless the kernel has 434 * registered such use. 435 */ 436 if (npxdna()) 437 return; 438 #endif 439 break; 440 441 case T_PROTFLT: /* general protection fault */ 442 case T_SEGNPFLT: /* segment not present fault */ 443 /* 444 * Invalid segment selectors and out of bounds 445 * %eip's and %esp's can be set up in user mode. 446 * This causes a fault in kernel mode when the 447 * kernel tries to return to user mode. We want 448 * to get this fault so that we can fix the 449 * problem here and not have to check all the 450 * selectors and pointers when the user changes 451 * them. 452 */ 453 #define MAYBE_DORETI_FAULT(where, whereto) \ 454 do { \ 455 if (frame.tf_eip == (int)where) { \ 456 frame.tf_eip = (int)whereto; \ 457 return; \ 458 } \ 459 } while (0) 460 461 if (intr_nesting_level == 0) { 462 /* 463 * Invalid %fs's and %gs's can be created using 464 * procfs or PT_SETREGS or by invalidating the 465 * underlying LDT entry. This causes a fault 466 * in kernel mode when the kernel attempts to 467 * switch contexts. Lose the bad context 468 * (XXX) so that we can continue, and generate 469 * a signal. 470 */ 471 if (frame.tf_eip == (int)cpu_switch_load_gs) { 472 curpcb->pcb_gs = 0; 473 psignal(p, SIGBUS); 474 return; 475 } 476 MAYBE_DORETI_FAULT(doreti_iret, 477 doreti_iret_fault); 478 MAYBE_DORETI_FAULT(doreti_popl_ds, 479 doreti_popl_ds_fault); 480 MAYBE_DORETI_FAULT(doreti_popl_es, 481 doreti_popl_es_fault); 482 MAYBE_DORETI_FAULT(doreti_popl_fs, 483 doreti_popl_fs_fault); 484 if (curpcb && curpcb->pcb_onfault) { 485 frame.tf_eip = (int)curpcb->pcb_onfault; 486 return; 487 } 488 } 489 break; 490 491 case T_TSSFLT: 492 /* 493 * PSL_NT can be set in user mode and isn't cleared 494 * automatically when the kernel is entered. This 495 * causes a TSS fault when the kernel attempts to 496 * `iret' because the TSS link is uninitialized. We 497 * want to get this fault so that we can fix the 498 * problem here and not every time the kernel is 499 * entered. 500 */ 501 if (frame.tf_eflags & PSL_NT) { 502 frame.tf_eflags &= ~PSL_NT; 503 return; 504 } 505 break; 506 507 case T_TRCTRAP: /* trace trap */ 508 if (frame.tf_eip == (int)IDTVEC(syscall)) { 509 /* 510 * We've just entered system mode via the 511 * syscall lcall. Continue single stepping 512 * silently until the syscall handler has 513 * saved the flags. 514 */ 515 return; 516 } 517 if (frame.tf_eip == (int)IDTVEC(syscall) + 1) { 518 /* 519 * The syscall handler has now saved the 520 * flags. Stop single stepping it. 521 */ 522 frame.tf_eflags &= ~PSL_T; 523 return; 524 } 525 /* 526 * Fall through. 527 */ 528 case T_BPTFLT: 529 /* 530 * If DDB is enabled, let it handle the debugger trap. 531 * Otherwise, debugger traps "can't happen". 532 */ 533 #ifdef DDB 534 if (kdb_trap (type, 0, &frame)) 535 return; 536 #endif 537 break; 538 539 #if NISA > 0 540 case T_NMI: 541 #ifdef POWERFAIL_NMI 542 #ifndef TIMER_FREQ 543 # define TIMER_FREQ 1193182 544 #endif 545 handle_powerfail: 546 { 547 static unsigned lastalert = 0; 548 549 if(time_second - lastalert > 10) 550 { 551 log(LOG_WARNING, "NMI: power fail\n"); 552 sysbeep(TIMER_FREQ/880, hz); 553 lastalert = time_second; 554 } 555 return; 556 } 557 #else /* !POWERFAIL_NMI */ 558 #ifdef DDB 559 /* NMI can be hooked up to a pushbutton for debugging */ 560 printf ("NMI ... going to debugger\n"); 561 if (kdb_trap (type, 0, &frame)) 562 return; 563 #endif /* DDB */ 564 /* machine/parity/power fail/"kitchen sink" faults */ 565 if (isa_nmi(code) == 0) return; 566 /* FALL THROUGH */ 567 #endif /* POWERFAIL_NMI */ 568 #endif /* NISA > 0 */ 569 } 570 571 trap_fatal(&frame, eva); 572 return; 573 } 574 575 /* Translate fault for emulators (e.g. Linux) */ 576 if (*p->p_sysent->sv_transtrap) 577 i = (*p->p_sysent->sv_transtrap)(i, type); 578 579 trapsignal(p, i, ucode); 580 581 #ifdef DEBUG 582 if (type <= MAX_TRAP_MSG) { 583 uprintf("fatal process exception: %s", 584 trap_msg[type]); 585 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 586 uprintf(", fault VA = 0x%lx", (u_long)eva); 587 uprintf("\n"); 588 } 589 #endif 590 591 out: 592 userret(p, &frame, sticks); 593 } 594 595 #ifdef notyet 596 /* 597 * This version doesn't allow a page fault to user space while 598 * in the kernel. The rest of the kernel needs to be made "safe" 599 * before this can be used. I think the only things remaining 600 * to be made safe are the iBCS2 code and the process tracing/ 601 * debugging code. 602 */ 603 static int 604 trap_pfault(frame, usermode, eva) 605 struct trapframe *frame; 606 int usermode; 607 vm_offset_t eva; 608 { 609 vm_offset_t va; 610 struct vmspace *vm = NULL; 611 vm_map_t map = 0; 612 int rv = 0; 613 vm_prot_t ftype; 614 struct proc *p = curproc; 615 616 if (frame->tf_err & PGEX_W) 617 ftype = VM_PROT_READ | VM_PROT_WRITE; 618 else 619 ftype = VM_PROT_READ; 620 621 va = trunc_page(eva); 622 if (va < VM_MIN_KERNEL_ADDRESS) { 623 vm_offset_t v; 624 vm_page_t mpte; 625 626 if (p == NULL || 627 (!usermode && va < VM_MAXUSER_ADDRESS && 628 (intr_nesting_level != 0 || curpcb == NULL || 629 curpcb->pcb_onfault == NULL))) { 630 trap_fatal(frame, eva); 631 return (-1); 632 } 633 634 /* 635 * This is a fault on non-kernel virtual memory. 636 * vm is initialized above to NULL. If curproc is NULL 637 * or curproc->p_vmspace is NULL the fault is fatal. 638 */ 639 vm = p->p_vmspace; 640 if (vm == NULL) 641 goto nogo; 642 643 map = &vm->vm_map; 644 645 /* 646 * Keep swapout from messing with us during this 647 * critical time. 648 */ 649 ++p->p_lock; 650 651 /* 652 * Grow the stack if necessary 653 */ 654 /* grow_stack returns false only if va falls into 655 * a growable stack region and the stack growth 656 * fails. It returns true if va was not within 657 * a growable stack region, or if the stack 658 * growth succeeded. 659 */ 660 if (!grow_stack (p, va)) { 661 rv = KERN_FAILURE; 662 --p->p_lock; 663 goto nogo; 664 } 665 666 /* Fault in the user page: */ 667 rv = vm_fault(map, va, ftype, 668 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 669 670 --p->p_lock; 671 } else { 672 /* 673 * Don't allow user-mode faults in kernel address space. 674 */ 675 if (usermode) 676 goto nogo; 677 678 /* 679 * Since we know that kernel virtual address addresses 680 * always have pte pages mapped, we just have to fault 681 * the page. 682 */ 683 rv = vm_fault(kernel_map, va, ftype, FALSE); 684 } 685 686 if (rv == KERN_SUCCESS) 687 return (0); 688 nogo: 689 if (!usermode) { 690 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 691 frame->tf_eip = (int)curpcb->pcb_onfault; 692 return (0); 693 } 694 trap_fatal(frame, eva); 695 return (-1); 696 } 697 698 /* kludge to pass faulting virtual address to sendsig */ 699 frame->tf_err = eva; 700 701 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 702 } 703 #endif 704 705 int 706 trap_pfault(frame, usermode, eva) 707 struct trapframe *frame; 708 int usermode; 709 vm_offset_t eva; 710 { 711 vm_offset_t va; 712 struct vmspace *vm = NULL; 713 vm_map_t map = 0; 714 int rv = 0; 715 vm_prot_t ftype; 716 struct proc *p = curproc; 717 718 va = trunc_page(eva); 719 if (va >= KERNBASE) { 720 /* 721 * Don't allow user-mode faults in kernel address space. 722 * An exception: if the faulting address is the invalid 723 * instruction entry in the IDT, then the Intel Pentium 724 * F00F bug workaround was triggered, and we need to 725 * treat it is as an illegal instruction, and not a page 726 * fault. 727 */ 728 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 729 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) { 730 frame->tf_trapno = T_PRIVINFLT; 731 return -2; 732 } 733 #endif 734 if (usermode) 735 goto nogo; 736 737 map = kernel_map; 738 } else { 739 /* 740 * This is a fault on non-kernel virtual memory. 741 * vm is initialized above to NULL. If curproc is NULL 742 * or curproc->p_vmspace is NULL the fault is fatal. 743 */ 744 if (p != NULL) 745 vm = p->p_vmspace; 746 747 if (vm == NULL) 748 goto nogo; 749 750 map = &vm->vm_map; 751 } 752 753 if (frame->tf_err & PGEX_W) 754 ftype = VM_PROT_READ | VM_PROT_WRITE; 755 else 756 ftype = VM_PROT_READ; 757 758 if (map != kernel_map) { 759 /* 760 * Keep swapout from messing with us during this 761 * critical time. 762 */ 763 ++p->p_lock; 764 765 /* 766 * Grow the stack if necessary 767 */ 768 /* grow_stack returns false only if va falls into 769 * a growable stack region and the stack growth 770 * fails. It returns true if va was not within 771 * a growable stack region, or if the stack 772 * growth succeeded. 773 */ 774 if (!grow_stack (p, va)) { 775 rv = KERN_FAILURE; 776 --p->p_lock; 777 goto nogo; 778 } 779 780 /* Fault in the user page: */ 781 rv = vm_fault(map, va, ftype, 782 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY : 0); 783 784 --p->p_lock; 785 } else { 786 /* 787 * Don't have to worry about process locking or stacks in the kernel. 788 */ 789 rv = vm_fault(map, va, ftype, FALSE); 790 } 791 792 if (rv == KERN_SUCCESS) 793 return (0); 794 nogo: 795 if (!usermode) { 796 if (intr_nesting_level == 0 && curpcb && curpcb->pcb_onfault) { 797 frame->tf_eip = (int)curpcb->pcb_onfault; 798 return (0); 799 } 800 trap_fatal(frame, eva); 801 return (-1); 802 } 803 804 /* kludge to pass faulting virtual address to sendsig */ 805 frame->tf_err = eva; 806 807 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 808 } 809 810 static void 811 trap_fatal(frame, eva) 812 struct trapframe *frame; 813 vm_offset_t eva; 814 { 815 int code, type, ss, esp; 816 struct soft_segment_descriptor softseg; 817 818 code = frame->tf_err; 819 type = frame->tf_trapno; 820 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 821 822 if (type <= MAX_TRAP_MSG) 823 printf("\n\nFatal trap %d: %s while in %s mode\n", 824 type, trap_msg[type], 825 frame->tf_eflags & PSL_VM ? "vm86" : 826 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 827 #ifdef SMP 828 /* three seperate prints in case of a trap on an unmapped page */ 829 printf("mp_lock = %08x; ", mp_lock); 830 printf("cpuid = %d; ", cpuid); 831 printf("lapic.id = %08x\n", lapic.id); 832 #endif 833 if (type == T_PAGEFLT) { 834 printf("fault virtual address = 0x%x\n", eva); 835 printf("fault code = %s %s, %s\n", 836 code & PGEX_U ? "user" : "supervisor", 837 code & PGEX_W ? "write" : "read", 838 code & PGEX_P ? "protection violation" : "page not present"); 839 } 840 printf("instruction pointer = 0x%x:0x%x\n", 841 frame->tf_cs & 0xffff, frame->tf_eip); 842 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 843 ss = frame->tf_ss & 0xffff; 844 esp = frame->tf_esp; 845 } else { 846 ss = GSEL(GDATA_SEL, SEL_KPL); 847 esp = (int)&frame->tf_esp; 848 } 849 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 850 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 851 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 852 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 853 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 854 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 855 softseg.ssd_gran); 856 printf("processor eflags = "); 857 if (frame->tf_eflags & PSL_T) 858 printf("trace trap, "); 859 if (frame->tf_eflags & PSL_I) 860 printf("interrupt enabled, "); 861 if (frame->tf_eflags & PSL_NT) 862 printf("nested task, "); 863 if (frame->tf_eflags & PSL_RF) 864 printf("resume, "); 865 if (frame->tf_eflags & PSL_VM) 866 printf("vm86, "); 867 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 868 printf("current process = "); 869 if (curproc) { 870 printf("%lu (%s)\n", 871 (u_long)curproc->p_pid, curproc->p_comm ? 872 curproc->p_comm : ""); 873 } else { 874 printf("Idle\n"); 875 } 876 printf("interrupt mask = "); 877 if ((cpl & net_imask) == net_imask) 878 printf("net "); 879 if ((cpl & tty_imask) == tty_imask) 880 printf("tty "); 881 if ((cpl & bio_imask) == bio_imask) 882 printf("bio "); 883 if ((cpl & cam_imask) == cam_imask) 884 printf("cam "); 885 if (cpl == 0) 886 printf("none"); 887 #ifdef SMP 888 /** 889 * XXX FIXME: 890 * we probably SHOULD have stopped the other CPUs before now! 891 * another CPU COULD have been touching cpl at this moment... 892 */ 893 printf(" <- SMP: XXX"); 894 #endif 895 printf("\n"); 896 897 #ifdef KDB 898 if (kdb_trap(&psl)) 899 return; 900 #endif 901 #ifdef DDB 902 if ((debugger_on_panic || in_Debugger) && kdb_trap(type, 0, frame)) 903 return; 904 #endif 905 printf("trap number = %d\n", type); 906 if (type <= MAX_TRAP_MSG) 907 panic(trap_msg[type]); 908 else 909 panic("unknown/reserved trap"); 910 } 911 912 /* 913 * Double fault handler. Called when a fault occurs while writing 914 * a frame for a trap/exception onto the stack. This usually occurs 915 * when the stack overflows (such is the case with infinite recursion, 916 * for example). 917 * 918 * XXX Note that the current PTD gets replaced by IdlePTD when the 919 * task switch occurs. This means that the stack that was active at 920 * the time of the double fault is not available at <kstack> unless 921 * the machine was idle when the double fault occurred. The downside 922 * of this is that "trace <ebp>" in ddb won't work. 923 */ 924 void 925 dblfault_handler() 926 { 927 printf("\nFatal double fault:\n"); 928 printf("eip = 0x%x\n", common_tss.tss_eip); 929 printf("esp = 0x%x\n", common_tss.tss_esp); 930 printf("ebp = 0x%x\n", common_tss.tss_ebp); 931 #ifdef SMP 932 /* three seperate prints in case of a trap on an unmapped page */ 933 printf("mp_lock = %08x; ", mp_lock); 934 printf("cpuid = %d; ", cpuid); 935 printf("lapic.id = %08x\n", lapic.id); 936 #endif 937 panic("double fault"); 938 } 939 940 /* 941 * Compensate for 386 brain damage (missing URKR). 942 * This is a little simpler than the pagefault handler in trap() because 943 * it the page tables have already been faulted in and high addresses 944 * are thrown out early for other reasons. 945 */ 946 int trapwrite(addr) 947 unsigned addr; 948 { 949 struct proc *p; 950 vm_offset_t va; 951 struct vmspace *vm; 952 int rv; 953 954 va = trunc_page((vm_offset_t)addr); 955 /* 956 * XXX - MAX is END. Changed > to >= for temp. fix. 957 */ 958 if (va >= VM_MAXUSER_ADDRESS) 959 return (1); 960 961 p = curproc; 962 vm = p->p_vmspace; 963 964 ++p->p_lock; 965 966 if (!grow_stack (p, va)) { 967 --p->p_lock; 968 return (1); 969 } 970 971 /* 972 * fault the data page 973 */ 974 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, VM_FAULT_DIRTY); 975 976 --p->p_lock; 977 978 if (rv != KERN_SUCCESS) 979 return 1; 980 981 return (0); 982 } 983 984 /* 985 * System call request from POSIX system call gate interface to kernel. 986 * Like trap(), argument is call by reference. 987 */ 988 void 989 syscall(frame) 990 struct trapframe frame; 991 { 992 caddr_t params; 993 int i; 994 struct sysent *callp; 995 struct proc *p = curproc; 996 u_quad_t sticks; 997 int error; 998 int args[8]; 999 u_int code; 1000 1001 #ifdef DIAGNOSTIC 1002 if (ISPL(frame.tf_cs) != SEL_UPL) 1003 panic("syscall"); 1004 #endif 1005 sticks = p->p_sticks; 1006 p->p_md.md_regs = &frame; 1007 params = (caddr_t)frame.tf_esp + sizeof(int); 1008 code = frame.tf_eax; 1009 if (p->p_sysent->sv_prepsyscall) { 1010 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); 1011 } else { 1012 /* 1013 * Need to check if this is a 32 bit or 64 bit syscall. 1014 */ 1015 if (code == SYS_syscall) { 1016 /* 1017 * Code is first argument, followed by actual args. 1018 */ 1019 code = fuword(params); 1020 params += sizeof(int); 1021 } else if (code == SYS___syscall) { 1022 /* 1023 * Like syscall, but code is a quad, so as to maintain 1024 * quad alignment for the rest of the arguments. 1025 */ 1026 code = fuword(params); 1027 params += sizeof(quad_t); 1028 } 1029 } 1030 1031 if (p->p_sysent->sv_mask) 1032 code &= p->p_sysent->sv_mask; 1033 1034 if (code >= p->p_sysent->sv_size) 1035 callp = &p->p_sysent->sv_table[0]; 1036 else 1037 callp = &p->p_sysent->sv_table[code]; 1038 1039 if (params && (i = callp->sy_narg * sizeof(int)) && 1040 (error = copyin(params, (caddr_t)args, (u_int)i))) { 1041 #ifdef KTRACE 1042 if (KTRPOINT(p, KTR_SYSCALL)) 1043 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 1044 #endif 1045 goto bad; 1046 } 1047 #ifdef KTRACE 1048 if (KTRPOINT(p, KTR_SYSCALL)) 1049 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 1050 #endif 1051 p->p_retval[0] = 0; 1052 p->p_retval[1] = frame.tf_edx; 1053 1054 STOPEVENT(p, S_SCE, callp->sy_narg); 1055 1056 error = (*callp->sy_call)(p, args); 1057 1058 switch (error) { 1059 1060 case 0: 1061 /* 1062 * Reinitialize proc pointer `p' as it may be different 1063 * if this is a child returning from fork syscall. 1064 */ 1065 p = curproc; 1066 frame.tf_eax = p->p_retval[0]; 1067 frame.tf_edx = p->p_retval[1]; 1068 frame.tf_eflags &= ~PSL_C; 1069 break; 1070 1071 case ERESTART: 1072 /* 1073 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 1074 * int 0x80 is 2 bytes. We saved this in tf_err. 1075 */ 1076 frame.tf_eip -= frame.tf_err; 1077 break; 1078 1079 case EJUSTRETURN: 1080 break; 1081 1082 default: 1083 bad: 1084 if (p->p_sysent->sv_errsize) { 1085 if (error >= p->p_sysent->sv_errsize) 1086 error = -1; /* XXX */ 1087 else 1088 error = p->p_sysent->sv_errtbl[error]; 1089 } 1090 frame.tf_eax = error; 1091 frame.tf_eflags |= PSL_C; 1092 break; 1093 } 1094 1095 if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) { 1096 /* Traced syscall. */ 1097 frame.tf_eflags &= ~PSL_T; 1098 trapsignal(p, SIGTRAP, 0); 1099 } 1100 1101 userret(p, &frame, sticks); 1102 1103 #ifdef KTRACE 1104 if (KTRPOINT(p, KTR_SYSRET)) 1105 ktrsysret(p->p_tracep, code, error, p->p_retval[0]); 1106 #endif 1107 1108 /* 1109 * This works because errno is findable through the 1110 * register set. If we ever support an emulation where this 1111 * is not the case, this code will need to be revisited. 1112 */ 1113 STOPEVENT(p, S_SCX, code); 1114 1115 } 1116 1117 /* 1118 * Simplified back end of syscall(), used when returning from fork() 1119 * directly into user mode. 1120 */ 1121 void 1122 fork_return(p, frame) 1123 struct proc *p; 1124 struct trapframe frame; 1125 { 1126 frame.tf_eax = 0; /* Child returns zero */ 1127 frame.tf_eflags &= ~PSL_C; /* success */ 1128 frame.tf_edx = 1; 1129 1130 userret(p, &frame, 0); 1131 #ifdef KTRACE 1132 if (KTRPOINT(p, KTR_SYSRET)) 1133 ktrsysret(p->p_tracep, SYS_fork, 0, 0); 1134 #endif 1135 } 1136