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_clock.h" 46 #include "opt_cpu.h" 47 #include "opt_ddb.h" 48 #include "opt_isa.h" 49 #include "opt_ktrace.h" 50 #include "opt_npx.h" 51 #include "opt_trap.h" 52 53 #include <sys/param.h> 54 #include <sys/bus.h> 55 #include <sys/systm.h> 56 #include <sys/proc.h> 57 #include <sys/pioctl.h> 58 #include <sys/ipl.h> 59 #include <sys/kernel.h> 60 #include <sys/ktr.h> 61 #include <sys/mutex.h> 62 #include <sys/resourcevar.h> 63 #include <sys/signalvar.h> 64 #include <sys/syscall.h> 65 #include <sys/sysctl.h> 66 #include <sys/sysent.h> 67 #include <sys/uio.h> 68 #include <sys/vmmeter.h> 69 #ifdef KTRACE 70 #include <sys/ktrace.h> 71 #endif 72 73 #include <vm/vm.h> 74 #include <vm/vm_param.h> 75 #include <sys/lock.h> 76 #include <vm/pmap.h> 77 #include <vm/vm_kern.h> 78 #include <vm/vm_map.h> 79 #include <vm/vm_page.h> 80 #include <vm/vm_extern.h> 81 82 #include <machine/cpu.h> 83 #include <machine/md_var.h> 84 #include <machine/pcb.h> 85 #ifdef SMP 86 #include <machine/smp.h> 87 #endif 88 #include <machine/tss.h> 89 90 #include <i386/isa/icu.h> 91 #include <i386/isa/intr_machdep.h> 92 93 #ifdef POWERFAIL_NMI 94 #include <sys/syslog.h> 95 #include <machine/clock.h> 96 #endif 97 98 #include <machine/vm86.h> 99 100 #include <ddb/ddb.h> 101 102 #include <sys/sysctl.h> 103 104 int (*pmath_emulate) __P((struct trapframe *)); 105 106 extern void trap __P((struct trapframe frame)); 107 extern int trapwrite __P((unsigned addr)); 108 extern void syscall __P((struct trapframe frame)); 109 extern void ast __P((struct trapframe *framep)); 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(lcall_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 "", /* 7 unused */ 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 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 151 extern int has_f00f_bug; 152 #endif 153 154 #ifdef DDB 155 static int ddb_on_nmi = 1; 156 SYSCTL_INT(_machdep, OID_AUTO, ddb_on_nmi, CTLFLAG_RW, 157 &ddb_on_nmi, 0, "Go to DDB on NMI"); 158 #endif 159 static int panic_on_nmi = 1; 160 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW, 161 &panic_on_nmi, 0, "Panic on NMI"); 162 163 #ifdef WITNESS 164 extern char *syscallnames[]; 165 #endif 166 167 void 168 userret(p, frame, oticks) 169 struct proc *p; 170 struct trapframe *frame; 171 u_quad_t oticks; 172 { 173 int sig; 174 175 while ((sig = CURSIG(p)) != 0) { 176 if (!mtx_owned(&Giant)) 177 mtx_lock(&Giant); 178 postsig(sig); 179 } 180 181 mtx_lock_spin(&sched_lock); 182 p->p_pri.pri_level = p->p_pri.pri_user; 183 if (resched_wanted()) { 184 /* 185 * Since we are curproc, clock will normally just change 186 * our priority without moving us from one queue to another 187 * (since the running process is not on a queue.) 188 * If that happened after we setrunqueue ourselves but before we 189 * mi_switch()'ed, we might not be on the queue indicated by 190 * our priority. 191 */ 192 DROP_GIANT_NOSWITCH(); 193 setrunqueue(p); 194 p->p_stats->p_ru.ru_nivcsw++; 195 mi_switch(); 196 mtx_unlock_spin(&sched_lock); 197 PICKUP_GIANT(); 198 while ((sig = CURSIG(p)) != 0) { 199 if (!mtx_owned(&Giant)) 200 mtx_lock(&Giant); 201 postsig(sig); 202 } 203 mtx_lock_spin(&sched_lock); 204 } 205 206 /* 207 * Charge system time if profiling. 208 */ 209 if (p->p_sflag & PS_PROFIL) { 210 mtx_unlock_spin(&sched_lock); 211 /* XXX - do we need Giant? */ 212 if (!mtx_owned(&Giant)) 213 mtx_lock(&Giant); 214 addupc_task(p, TRAPF_PC(frame), 215 (u_int)(p->p_sticks - oticks) * psratio); 216 } else 217 mtx_unlock_spin(&sched_lock); 218 } 219 220 /* 221 * Exception, fault, and trap interface to the FreeBSD kernel. 222 * This common code is called from assembly language IDT gate entry 223 * routines that prepare a suitable stack frame, and restore this 224 * frame after the exception has been processed. 225 */ 226 227 void 228 trap(frame) 229 struct trapframe frame; 230 { 231 struct proc *p = curproc; 232 u_quad_t sticks = 0; 233 int i = 0, ucode = 0, type, code; 234 vm_offset_t eva; 235 #ifdef POWERFAIL_NMI 236 static int lastalert = 0; 237 #endif 238 239 atomic_add_int(&cnt.v_trap, 1); 240 241 if ((frame.tf_eflags & PSL_I) == 0) { 242 /* 243 * Buggy application or kernel code has disabled 244 * interrupts and then trapped. Enabling interrupts 245 * now is wrong, but it is better than running with 246 * interrupts disabled until they are accidentally 247 * enabled later. XXX This is really bad if we trap 248 * while holding a spin lock. 249 */ 250 type = frame.tf_trapno; 251 if (ISPL(frame.tf_cs) == SEL_UPL || (frame.tf_eflags & PSL_VM)) 252 printf( 253 "pid %ld (%s): trap %d with interrupts disabled\n", 254 (long)curproc->p_pid, curproc->p_comm, type); 255 else if (type != T_BPTFLT && type != T_TRCTRAP) { 256 /* 257 * XXX not quite right, since this may be for a 258 * multiple fault in user mode. 259 */ 260 printf("kernel trap %d with interrupts disabled\n", 261 type); 262 /* 263 * We should walk p_heldmtx here and see if any are 264 * spin mutexes, and not do this if so. 265 */ 266 enable_intr(); 267 } 268 } 269 270 eva = 0; 271 272 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 273 restart: 274 #endif 275 276 type = frame.tf_trapno; 277 code = frame.tf_err; 278 279 if ((ISPL(frame.tf_cs) == SEL_UPL) || 280 ((frame.tf_eflags & PSL_VM) && !in_vm86call)) { 281 /* user trap */ 282 283 mtx_lock_spin(&sched_lock); 284 sticks = p->p_sticks; 285 mtx_unlock_spin(&sched_lock); 286 p->p_md.md_regs = &frame; 287 288 switch (type) { 289 case T_PRIVINFLT: /* privileged instruction fault */ 290 ucode = type; 291 i = SIGILL; 292 break; 293 294 case T_BPTFLT: /* bpt instruction fault */ 295 case T_TRCTRAP: /* trace trap */ 296 frame.tf_eflags &= ~PSL_T; 297 i = SIGTRAP; 298 break; 299 300 case T_ARITHTRAP: /* arithmetic trap */ 301 ucode = code; 302 i = SIGFPE; 303 break; 304 305 /* 306 * The following two traps can happen in 307 * vm86 mode, and, if so, we want to handle 308 * them specially. 309 */ 310 case T_PROTFLT: /* general protection fault */ 311 case T_STKFLT: /* stack fault */ 312 if (frame.tf_eflags & PSL_VM) { 313 mtx_lock(&Giant); 314 i = vm86_emulate((struct vm86frame *)&frame); 315 mtx_unlock(&Giant); 316 if (i == 0) 317 goto user; 318 break; 319 } 320 /* FALL THROUGH */ 321 322 case T_SEGNPFLT: /* segment not present fault */ 323 case T_TSSFLT: /* invalid TSS fault */ 324 case T_DOUBLEFLT: /* double fault */ 325 default: 326 ucode = code + BUS_SEGM_FAULT ; 327 i = SIGBUS; 328 break; 329 330 case T_PAGEFLT: /* page fault */ 331 /* 332 * For some Cyrix CPUs, %cr2 is clobbered by 333 * interrupts. This problem is worked around by using 334 * an interrupt gate for the pagefault handler. We 335 * are finally ready to read %cr2 and then must 336 * reenable interrupts. 337 */ 338 eva = rcr2(); 339 enable_intr(); 340 mtx_lock(&Giant); 341 i = trap_pfault(&frame, TRUE, eva); 342 mtx_unlock(&Giant); 343 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 344 if (i == -2) { 345 /* 346 * f00f hack workaround has triggered, treat 347 * as illegal instruction not page fault. 348 */ 349 frame.tf_trapno = T_PRIVINFLT; 350 goto restart; 351 } 352 #endif 353 if (i == -1) 354 goto out; 355 if (i == 0) 356 goto user; 357 358 ucode = T_PAGEFLT; 359 break; 360 361 case T_DIVIDE: /* integer divide fault */ 362 ucode = FPE_INTDIV; 363 i = SIGFPE; 364 break; 365 366 #ifdef DEV_ISA 367 case T_NMI: 368 #ifdef POWERFAIL_NMI 369 #ifndef TIMER_FREQ 370 # define TIMER_FREQ 1193182 371 #endif 372 mtx_lock(&Giant); 373 if (time_second - lastalert > 10) { 374 log(LOG_WARNING, "NMI: power fail\n"); 375 sysbeep(TIMER_FREQ/880, hz); 376 lastalert = time_second; 377 } 378 mtx_unlock(&Giant); 379 goto out; 380 #else /* !POWERFAIL_NMI */ 381 /* machine/parity/power fail/"kitchen sink" faults */ 382 /* XXX Giant */ 383 if (isa_nmi(code) == 0) { 384 #ifdef DDB 385 /* 386 * NMI can be hooked up to a pushbutton 387 * for debugging. 388 */ 389 if (ddb_on_nmi) { 390 printf ("NMI ... going to debugger\n"); 391 kdb_trap (type, 0, &frame); 392 } 393 #endif /* DDB */ 394 goto out; 395 } else if (panic_on_nmi) 396 panic("NMI indicates hardware failure"); 397 break; 398 #endif /* POWERFAIL_NMI */ 399 #endif /* DEV_ISA */ 400 401 case T_OFLOW: /* integer overflow fault */ 402 ucode = FPE_INTOVF; 403 i = SIGFPE; 404 break; 405 406 case T_BOUND: /* bounds check fault */ 407 ucode = FPE_FLTSUB; 408 i = SIGFPE; 409 break; 410 411 case T_DNA: 412 #ifdef DEV_NPX 413 /* transparent fault (due to context switch "late") */ 414 if (npxdna()) 415 goto out; 416 #endif 417 if (!pmath_emulate) { 418 i = SIGFPE; 419 ucode = FPE_FPU_NP_TRAP; 420 break; 421 } 422 mtx_lock(&Giant); 423 i = (*pmath_emulate)(&frame); 424 mtx_unlock(&Giant); 425 if (i == 0) { 426 if (!(frame.tf_eflags & PSL_T)) 427 goto out; 428 frame.tf_eflags &= ~PSL_T; 429 i = SIGTRAP; 430 } 431 /* else ucode = emulator_only_knows() XXX */ 432 break; 433 434 case T_FPOPFLT: /* FPU operand fetch fault */ 435 ucode = T_FPOPFLT; 436 i = SIGILL; 437 break; 438 } 439 } else { 440 /* kernel trap */ 441 442 switch (type) { 443 case T_PAGEFLT: /* page fault */ 444 /* 445 * For some Cyrix CPUs, %cr2 is clobbered by 446 * interrupts. This problem is worked around by using 447 * an interrupt gate for the pagefault handler. We 448 * are finally ready to read %cr2 and then must 449 * reenable interrupts. 450 */ 451 eva = rcr2(); 452 enable_intr(); 453 mtx_lock(&Giant); 454 (void) trap_pfault(&frame, FALSE, eva); 455 mtx_unlock(&Giant); 456 goto out; 457 458 case T_DNA: 459 #ifdef DEV_NPX 460 /* 461 * The kernel is apparently using npx for copying. 462 * XXX this should be fatal unless the kernel has 463 * registered such use. 464 */ 465 if (npxdna()) 466 goto out; 467 #endif 468 break; 469 470 /* 471 * The following two traps can happen in 472 * vm86 mode, and, if so, we want to handle 473 * them specially. 474 */ 475 case T_PROTFLT: /* general protection fault */ 476 case T_STKFLT: /* stack fault */ 477 if (frame.tf_eflags & PSL_VM) { 478 mtx_lock(&Giant); 479 i = vm86_emulate((struct vm86frame *)&frame); 480 mtx_unlock(&Giant); 481 if (i != 0) 482 /* 483 * returns to original process 484 */ 485 vm86_trap((struct vm86frame *)&frame); 486 goto out; 487 } 488 if (type == T_STKFLT) 489 break; 490 491 /* FALL THROUGH */ 492 493 case T_SEGNPFLT: /* segment not present fault */ 494 if (in_vm86call) 495 break; 496 497 if (p->p_intr_nesting_level != 0) 498 break; 499 500 /* 501 * Invalid %fs's and %gs's can be created using 502 * procfs or PT_SETREGS or by invalidating the 503 * underlying LDT entry. This causes a fault 504 * in kernel mode when the kernel attempts to 505 * switch contexts. Lose the bad context 506 * (XXX) so that we can continue, and generate 507 * a signal. 508 */ 509 if (frame.tf_eip == (int)cpu_switch_load_gs) { 510 PCPU_GET(curpcb)->pcb_gs = 0; 511 mtx_lock(&Giant); 512 psignal(p, SIGBUS); 513 mtx_unlock(&Giant); 514 goto out; 515 } 516 517 /* 518 * Invalid segment selectors and out of bounds 519 * %eip's and %esp's can be set up in user mode. 520 * This causes a fault in kernel mode when the 521 * kernel tries to return to user mode. We want 522 * to get this fault so that we can fix the 523 * problem here and not have to check all the 524 * selectors and pointers when the user changes 525 * them. 526 */ 527 if (frame.tf_eip == (int)doreti_iret) { 528 frame.tf_eip = (int)doreti_iret_fault; 529 goto out; 530 } 531 if (frame.tf_eip == (int)doreti_popl_ds) { 532 frame.tf_eip = (int)doreti_popl_ds_fault; 533 goto out; 534 } 535 if (frame.tf_eip == (int)doreti_popl_es) { 536 frame.tf_eip = (int)doreti_popl_es_fault; 537 goto out; 538 } 539 if (frame.tf_eip == (int)doreti_popl_fs) { 540 frame.tf_eip = (int)doreti_popl_fs_fault; 541 goto out; 542 } 543 if (PCPU_GET(curpcb) != NULL && 544 PCPU_GET(curpcb)->pcb_onfault != NULL) { 545 frame.tf_eip = 546 (int)PCPU_GET(curpcb)->pcb_onfault; 547 goto out; 548 } 549 break; 550 551 case T_TSSFLT: 552 /* 553 * PSL_NT can be set in user mode and isn't cleared 554 * automatically when the kernel is entered. This 555 * causes a TSS fault when the kernel attempts to 556 * `iret' because the TSS link is uninitialized. We 557 * want to get this fault so that we can fix the 558 * problem here and not every time the kernel is 559 * entered. 560 */ 561 if (frame.tf_eflags & PSL_NT) { 562 frame.tf_eflags &= ~PSL_NT; 563 goto out; 564 } 565 break; 566 567 case T_TRCTRAP: /* trace trap */ 568 if (frame.tf_eip == (int)IDTVEC(lcall_syscall)) { 569 /* 570 * We've just entered system mode via the 571 * syscall lcall. Continue single stepping 572 * silently until the syscall handler has 573 * saved the flags. 574 */ 575 goto out; 576 } 577 if (frame.tf_eip == (int)IDTVEC(lcall_syscall) + 1) { 578 /* 579 * The syscall handler has now saved the 580 * flags. Stop single stepping it. 581 */ 582 frame.tf_eflags &= ~PSL_T; 583 goto out; 584 } 585 /* 586 * Ignore debug register trace traps due to 587 * accesses in the user's address space, which 588 * can happen under several conditions such as 589 * if a user sets a watchpoint on a buffer and 590 * then passes that buffer to a system call. 591 * We still want to get TRCTRAPS for addresses 592 * in kernel space because that is useful when 593 * debugging the kernel. 594 */ 595 /* XXX Giant */ 596 if (user_dbreg_trap() && !in_vm86call) { 597 /* 598 * Reset breakpoint bits because the 599 * processor doesn't 600 */ 601 load_dr6(rdr6() & 0xfffffff0); 602 goto out; 603 } 604 /* 605 * Fall through (TRCTRAP kernel mode, kernel address) 606 */ 607 case T_BPTFLT: 608 /* 609 * If DDB is enabled, let it handle the debugger trap. 610 * Otherwise, debugger traps "can't happen". 611 */ 612 #ifdef DDB 613 /* XXX Giant */ 614 if (kdb_trap (type, 0, &frame)) 615 goto out; 616 #endif 617 break; 618 619 #ifdef DEV_ISA 620 case T_NMI: 621 #ifdef POWERFAIL_NMI 622 mtx_lock(&Giant); 623 if (time_second - lastalert > 10) { 624 log(LOG_WARNING, "NMI: power fail\n"); 625 sysbeep(TIMER_FREQ/880, hz); 626 lastalert = time_second; 627 } 628 mtx_unlock(&Giant); 629 goto out; 630 #else /* !POWERFAIL_NMI */ 631 /* XXX Giant */ 632 /* machine/parity/power fail/"kitchen sink" faults */ 633 if (isa_nmi(code) == 0) { 634 #ifdef DDB 635 /* 636 * NMI can be hooked up to a pushbutton 637 * for debugging. 638 */ 639 if (ddb_on_nmi) { 640 printf ("NMI ... going to debugger\n"); 641 kdb_trap (type, 0, &frame); 642 } 643 #endif /* DDB */ 644 goto out; 645 } else if (panic_on_nmi == 0) 646 goto out; 647 /* FALL THROUGH */ 648 #endif /* POWERFAIL_NMI */ 649 #endif /* DEV_ISA */ 650 } 651 652 mtx_lock(&Giant); 653 trap_fatal(&frame, eva); 654 mtx_unlock(&Giant); 655 goto out; 656 } 657 658 mtx_lock(&Giant); 659 /* Translate fault for emulators (e.g. Linux) */ 660 if (*p->p_sysent->sv_transtrap) 661 i = (*p->p_sysent->sv_transtrap)(i, type); 662 663 trapsignal(p, i, ucode); 664 665 #ifdef DEBUG 666 if (type <= MAX_TRAP_MSG) { 667 uprintf("fatal process exception: %s", 668 trap_msg[type]); 669 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 670 uprintf(", fault VA = 0x%lx", (u_long)eva); 671 uprintf("\n"); 672 } 673 #endif 674 mtx_unlock(&Giant); 675 676 user: 677 userret(p, &frame, sticks); 678 if (mtx_owned(&Giant)) 679 mtx_unlock(&Giant); 680 out: 681 return; 682 } 683 684 #ifdef notyet 685 /* 686 * This version doesn't allow a page fault to user space while 687 * in the kernel. The rest of the kernel needs to be made "safe" 688 * before this can be used. I think the only things remaining 689 * to be made safe are the iBCS2 code and the process tracing/ 690 * debugging code. 691 */ 692 static int 693 trap_pfault(frame, usermode, eva) 694 struct trapframe *frame; 695 int usermode; 696 vm_offset_t eva; 697 { 698 vm_offset_t va; 699 struct vmspace *vm = NULL; 700 vm_map_t map = 0; 701 int rv = 0; 702 vm_prot_t ftype; 703 struct proc *p = curproc; 704 705 if (frame->tf_err & PGEX_W) 706 ftype = VM_PROT_WRITE; 707 else 708 ftype = VM_PROT_READ; 709 710 va = trunc_page(eva); 711 if (va < VM_MIN_KERNEL_ADDRESS) { 712 vm_offset_t v; 713 vm_page_t mpte; 714 715 if (p == NULL || 716 (!usermode && va < VM_MAXUSER_ADDRESS && 717 (p->p_intr_nesting_level != 0 || 718 PCPU_GET(curpcb) == NULL || 719 PCPU_GET(curpcb)->pcb_onfault == NULL))) { 720 trap_fatal(frame, eva); 721 return (-1); 722 } 723 724 /* 725 * This is a fault on non-kernel virtual memory. 726 * vm is initialized above to NULL. If curproc is NULL 727 * or curproc->p_vmspace is NULL the fault is fatal. 728 */ 729 vm = p->p_vmspace; 730 if (vm == NULL) 731 goto nogo; 732 733 map = &vm->vm_map; 734 735 /* 736 * Keep swapout from messing with us during this 737 * critical time. 738 */ 739 PROC_LOCK(p); 740 ++p->p_lock; 741 PROC_UNLOCK(p); 742 743 /* 744 * Grow the stack if necessary 745 */ 746 /* grow_stack returns false only if va falls into 747 * a growable stack region and the stack growth 748 * fails. It returns true if va was not within 749 * a growable stack region, or if the stack 750 * growth succeeded. 751 */ 752 if (!grow_stack (p, va)) { 753 rv = KERN_FAILURE; 754 PROC_LOCK(p); 755 --p->p_lock; 756 PROC_UNLOCK(p); 757 goto nogo; 758 } 759 760 /* Fault in the user page: */ 761 rv = vm_fault(map, va, ftype, 762 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 763 : VM_FAULT_NORMAL); 764 765 PROC_LOCK(p); 766 --p->p_lock; 767 PROC_UNLOCK(p); 768 } else { 769 /* 770 * Don't allow user-mode faults in kernel address space. 771 */ 772 if (usermode) 773 goto nogo; 774 775 /* 776 * Since we know that kernel virtual address addresses 777 * always have pte pages mapped, we just have to fault 778 * the page. 779 */ 780 rv = vm_fault(kernel_map, va, ftype, VM_FAULT_NORMAL); 781 } 782 783 if (rv == KERN_SUCCESS) 784 return (0); 785 nogo: 786 if (!usermode) { 787 if (p->p_intr_nesting_level == 0 && 788 PCPU_GET(curpcb) != NULL && 789 PCPU_GET(curpcb)->pcb_onfault != NULL) { 790 frame->tf_eip = (int)PCPU_GET(curpcb)->pcb_onfault; 791 return (0); 792 } 793 trap_fatal(frame, eva); 794 return (-1); 795 } 796 797 /* kludge to pass faulting virtual address to sendsig */ 798 frame->tf_err = eva; 799 800 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 801 } 802 #endif 803 804 int 805 trap_pfault(frame, usermode, eva) 806 struct trapframe *frame; 807 int usermode; 808 vm_offset_t eva; 809 { 810 vm_offset_t va; 811 struct vmspace *vm = NULL; 812 vm_map_t map = 0; 813 int rv = 0; 814 vm_prot_t ftype; 815 struct proc *p = curproc; 816 817 va = trunc_page(eva); 818 if (va >= KERNBASE) { 819 /* 820 * Don't allow user-mode faults in kernel address space. 821 * An exception: if the faulting address is the invalid 822 * instruction entry in the IDT, then the Intel Pentium 823 * F00F bug workaround was triggered, and we need to 824 * treat it is as an illegal instruction, and not a page 825 * fault. 826 */ 827 #if defined(I586_CPU) && !defined(NO_F00F_HACK) 828 if ((eva == (unsigned int)&idt[6]) && has_f00f_bug) 829 return -2; 830 #endif 831 if (usermode) 832 goto nogo; 833 834 map = kernel_map; 835 } else { 836 /* 837 * This is a fault on non-kernel virtual memory. 838 * vm is initialized above to NULL. If curproc is NULL 839 * or curproc->p_vmspace is NULL the fault is fatal. 840 */ 841 if (p != NULL) 842 vm = p->p_vmspace; 843 844 if (vm == NULL) 845 goto nogo; 846 847 map = &vm->vm_map; 848 } 849 850 if (frame->tf_err & PGEX_W) 851 ftype = VM_PROT_WRITE; 852 else 853 ftype = VM_PROT_READ; 854 855 if (map != kernel_map) { 856 /* 857 * Keep swapout from messing with us during this 858 * critical time. 859 */ 860 PROC_LOCK(p); 861 ++p->p_lock; 862 PROC_UNLOCK(p); 863 864 /* 865 * Grow the stack if necessary 866 */ 867 /* grow_stack returns false only if va falls into 868 * a growable stack region and the stack growth 869 * fails. It returns true if va was not within 870 * a growable stack region, or if the stack 871 * growth succeeded. 872 */ 873 if (!grow_stack (p, va)) { 874 rv = KERN_FAILURE; 875 PROC_LOCK(p); 876 --p->p_lock; 877 PROC_UNLOCK(p); 878 goto nogo; 879 } 880 881 /* Fault in the user page: */ 882 rv = vm_fault(map, va, ftype, 883 (ftype & VM_PROT_WRITE) ? VM_FAULT_DIRTY 884 : VM_FAULT_NORMAL); 885 886 PROC_LOCK(p); 887 --p->p_lock; 888 PROC_UNLOCK(p); 889 } else { 890 /* 891 * Don't have to worry about process locking or stacks in the 892 * kernel. 893 */ 894 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 895 } 896 897 if (rv == KERN_SUCCESS) 898 return (0); 899 nogo: 900 if (!usermode) { 901 if (p->p_intr_nesting_level == 0 && 902 PCPU_GET(curpcb) != NULL && 903 PCPU_GET(curpcb)->pcb_onfault != NULL) { 904 frame->tf_eip = (int)PCPU_GET(curpcb)->pcb_onfault; 905 return (0); 906 } 907 trap_fatal(frame, eva); 908 return (-1); 909 } 910 911 /* kludge to pass faulting virtual address to sendsig */ 912 frame->tf_err = eva; 913 914 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 915 } 916 917 static void 918 trap_fatal(frame, eva) 919 struct trapframe *frame; 920 vm_offset_t eva; 921 { 922 int code, type, ss, esp; 923 struct soft_segment_descriptor softseg; 924 925 code = frame->tf_err; 926 type = frame->tf_trapno; 927 sdtossd(&gdt[IDXSEL(frame->tf_cs & 0xffff)].sd, &softseg); 928 929 if (type <= MAX_TRAP_MSG) 930 printf("\n\nFatal trap %d: %s while in %s mode\n", 931 type, trap_msg[type], 932 frame->tf_eflags & PSL_VM ? "vm86" : 933 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 934 #ifdef SMP 935 /* two separate prints in case of a trap on an unmapped page */ 936 printf("cpuid = %d; ", PCPU_GET(cpuid)); 937 printf("lapic.id = %08x\n", lapic.id); 938 #endif 939 if (type == T_PAGEFLT) { 940 printf("fault virtual address = 0x%x\n", eva); 941 printf("fault code = %s %s, %s\n", 942 code & PGEX_U ? "user" : "supervisor", 943 code & PGEX_W ? "write" : "read", 944 code & PGEX_P ? "protection violation" : "page not present"); 945 } 946 printf("instruction pointer = 0x%x:0x%x\n", 947 frame->tf_cs & 0xffff, frame->tf_eip); 948 if ((ISPL(frame->tf_cs) == SEL_UPL) || (frame->tf_eflags & PSL_VM)) { 949 ss = frame->tf_ss & 0xffff; 950 esp = frame->tf_esp; 951 } else { 952 ss = GSEL(GDATA_SEL, SEL_KPL); 953 esp = (int)&frame->tf_esp; 954 } 955 printf("stack pointer = 0x%x:0x%x\n", ss, esp); 956 printf("frame pointer = 0x%x:0x%x\n", ss, frame->tf_ebp); 957 printf("code segment = base 0x%x, limit 0x%x, type 0x%x\n", 958 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type); 959 printf(" = DPL %d, pres %d, def32 %d, gran %d\n", 960 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_def32, 961 softseg.ssd_gran); 962 printf("processor eflags = "); 963 if (frame->tf_eflags & PSL_T) 964 printf("trace trap, "); 965 if (frame->tf_eflags & PSL_I) 966 printf("interrupt enabled, "); 967 if (frame->tf_eflags & PSL_NT) 968 printf("nested task, "); 969 if (frame->tf_eflags & PSL_RF) 970 printf("resume, "); 971 if (frame->tf_eflags & PSL_VM) 972 printf("vm86, "); 973 printf("IOPL = %d\n", (frame->tf_eflags & PSL_IOPL) >> 12); 974 printf("current process = "); 975 if (curproc) { 976 printf("%lu (%s)\n", 977 (u_long)curproc->p_pid, curproc->p_comm ? 978 curproc->p_comm : ""); 979 } else { 980 printf("Idle\n"); 981 } 982 983 #ifdef KDB 984 if (kdb_trap(&psl)) 985 return; 986 #endif 987 #ifdef DDB 988 if ((debugger_on_panic || db_active) && kdb_trap(type, 0, frame)) 989 return; 990 #endif 991 printf("trap number = %d\n", type); 992 if (type <= MAX_TRAP_MSG) 993 panic(trap_msg[type]); 994 else 995 panic("unknown/reserved trap"); 996 } 997 998 /* 999 * Double fault handler. Called when a fault occurs while writing 1000 * a frame for a trap/exception onto the stack. This usually occurs 1001 * when the stack overflows (such is the case with infinite recursion, 1002 * for example). 1003 * 1004 * XXX Note that the current PTD gets replaced by IdlePTD when the 1005 * task switch occurs. This means that the stack that was active at 1006 * the time of the double fault is not available at <kstack> unless 1007 * the machine was idle when the double fault occurred. The downside 1008 * of this is that "trace <ebp>" in ddb won't work. 1009 */ 1010 void 1011 dblfault_handler() 1012 { 1013 printf("\nFatal double fault:\n"); 1014 printf("eip = 0x%x\n", PCPU_GET(common_tss.tss_eip)); 1015 printf("esp = 0x%x\n", PCPU_GET(common_tss.tss_esp)); 1016 printf("ebp = 0x%x\n", PCPU_GET(common_tss.tss_ebp)); 1017 #ifdef SMP 1018 /* two separate prints in case of a trap on an unmapped page */ 1019 printf("cpuid = %d; ", PCPU_GET(cpuid)); 1020 printf("lapic.id = %08x\n", lapic.id); 1021 #endif 1022 panic("double fault"); 1023 } 1024 1025 /* 1026 * Compensate for 386 brain damage (missing URKR). 1027 * This is a little simpler than the pagefault handler in trap() because 1028 * it the page tables have already been faulted in and high addresses 1029 * are thrown out early for other reasons. 1030 */ 1031 int trapwrite(addr) 1032 unsigned addr; 1033 { 1034 struct proc *p; 1035 vm_offset_t va; 1036 struct vmspace *vm; 1037 int rv; 1038 1039 va = trunc_page((vm_offset_t)addr); 1040 /* 1041 * XXX - MAX is END. Changed > to >= for temp. fix. 1042 */ 1043 if (va >= VM_MAXUSER_ADDRESS) 1044 return (1); 1045 1046 p = curproc; 1047 vm = p->p_vmspace; 1048 1049 PROC_LOCK(p); 1050 ++p->p_lock; 1051 PROC_UNLOCK(p); 1052 1053 if (!grow_stack (p, va)) { 1054 PROC_LOCK(p); 1055 --p->p_lock; 1056 PROC_UNLOCK(p); 1057 return (1); 1058 } 1059 1060 /* 1061 * fault the data page 1062 */ 1063 rv = vm_fault(&vm->vm_map, va, VM_PROT_WRITE, VM_FAULT_DIRTY); 1064 1065 PROC_LOCK(p); 1066 --p->p_lock; 1067 PROC_UNLOCK(p); 1068 1069 if (rv != KERN_SUCCESS) 1070 return 1; 1071 1072 return (0); 1073 } 1074 1075 /* 1076 * syscall - MP aware system call request C handler 1077 * 1078 * A system call is essentially treated as a trap except that the 1079 * MP lock is not held on entry or return. We are responsible for 1080 * obtaining the MP lock if necessary and for handling ASTs 1081 * (e.g. a task switch) prior to return. 1082 * 1083 * In general, only simple access and manipulation of curproc and 1084 * the current stack is allowed without having to hold MP lock. 1085 */ 1086 void 1087 syscall(frame) 1088 struct trapframe frame; 1089 { 1090 caddr_t params; 1091 int i; 1092 struct sysent *callp; 1093 struct proc *p = curproc; 1094 u_quad_t sticks; 1095 int error; 1096 int narg; 1097 int args[8]; 1098 u_int code; 1099 1100 atomic_add_int(&cnt.v_syscall, 1); 1101 1102 #ifdef DIAGNOSTIC 1103 if (ISPL(frame.tf_cs) != SEL_UPL) { 1104 mtx_lock(&Giant); 1105 panic("syscall"); 1106 /* NOT REACHED */ 1107 } 1108 #endif 1109 1110 mtx_lock_spin(&sched_lock); 1111 sticks = p->p_sticks; 1112 mtx_unlock_spin(&sched_lock); 1113 1114 p->p_md.md_regs = &frame; 1115 params = (caddr_t)frame.tf_esp + sizeof(int); 1116 code = frame.tf_eax; 1117 1118 if (p->p_sysent->sv_prepsyscall) { 1119 /* 1120 * The prep code is not MP aware. 1121 */ 1122 mtx_lock(&Giant); 1123 (*p->p_sysent->sv_prepsyscall)(&frame, args, &code, ¶ms); 1124 mtx_unlock(&Giant); 1125 } else { 1126 /* 1127 * Need to check if this is a 32 bit or 64 bit syscall. 1128 * fuword is MP aware. 1129 */ 1130 if (code == SYS_syscall) { 1131 /* 1132 * Code is first argument, followed by actual args. 1133 */ 1134 code = fuword(params); 1135 params += sizeof(int); 1136 } else if (code == SYS___syscall) { 1137 /* 1138 * Like syscall, but code is a quad, so as to maintain 1139 * quad alignment for the rest of the arguments. 1140 */ 1141 code = fuword(params); 1142 params += sizeof(quad_t); 1143 } 1144 } 1145 1146 if (p->p_sysent->sv_mask) 1147 code &= p->p_sysent->sv_mask; 1148 1149 if (code >= p->p_sysent->sv_size) 1150 callp = &p->p_sysent->sv_table[0]; 1151 else 1152 callp = &p->p_sysent->sv_table[code]; 1153 1154 narg = callp->sy_narg & SYF_ARGMASK; 1155 1156 /* 1157 * copyin is MP aware, but the tracing code is not 1158 */ 1159 if (params && (i = narg * sizeof(int)) && 1160 (error = copyin(params, (caddr_t)args, (u_int)i))) { 1161 mtx_lock(&Giant); 1162 #ifdef KTRACE 1163 if (KTRPOINT(p, KTR_SYSCALL)) 1164 ktrsyscall(p->p_tracep, code, narg, args); 1165 #endif 1166 goto bad; 1167 } 1168 1169 /* 1170 * Try to run the syscall without the MP lock if the syscall 1171 * is MP safe. We have to obtain the MP lock no matter what if 1172 * we are ktracing 1173 */ 1174 if ((callp->sy_narg & SYF_MPSAFE) == 0) { 1175 mtx_lock(&Giant); 1176 } 1177 1178 #ifdef KTRACE 1179 if (KTRPOINT(p, KTR_SYSCALL)) { 1180 if (!mtx_owned(&Giant)) 1181 mtx_lock(&Giant); 1182 ktrsyscall(p->p_tracep, code, narg, args); 1183 } 1184 #endif 1185 p->p_retval[0] = 0; 1186 p->p_retval[1] = frame.tf_edx; 1187 1188 STOPEVENT(p, S_SCE, narg); /* MP aware */ 1189 1190 error = (*callp->sy_call)(p, args); 1191 1192 /* 1193 * MP SAFE (we may or may not have the MP lock at this point) 1194 */ 1195 switch (error) { 1196 case 0: 1197 frame.tf_eax = p->p_retval[0]; 1198 frame.tf_edx = p->p_retval[1]; 1199 frame.tf_eflags &= ~PSL_C; 1200 break; 1201 1202 case ERESTART: 1203 /* 1204 * Reconstruct pc, assuming lcall $X,y is 7 bytes, 1205 * int 0x80 is 2 bytes. We saved this in tf_err. 1206 */ 1207 frame.tf_eip -= frame.tf_err; 1208 break; 1209 1210 case EJUSTRETURN: 1211 break; 1212 1213 default: 1214 bad: 1215 if (p->p_sysent->sv_errsize) { 1216 if (error >= p->p_sysent->sv_errsize) 1217 error = -1; /* XXX */ 1218 else 1219 error = p->p_sysent->sv_errtbl[error]; 1220 } 1221 frame.tf_eax = error; 1222 frame.tf_eflags |= PSL_C; 1223 break; 1224 } 1225 1226 /* 1227 * Traced syscall. trapsignal() is not MP aware. 1228 */ 1229 if ((frame.tf_eflags & PSL_T) && !(frame.tf_eflags & PSL_VM)) { 1230 if (!mtx_owned(&Giant)) 1231 mtx_lock(&Giant); 1232 frame.tf_eflags &= ~PSL_T; 1233 trapsignal(p, SIGTRAP, 0); 1234 } 1235 1236 /* 1237 * Handle reschedule and other end-of-syscall issues 1238 */ 1239 userret(p, &frame, sticks); 1240 1241 #ifdef KTRACE 1242 if (KTRPOINT(p, KTR_SYSRET)) { 1243 if (!mtx_owned(&Giant)) 1244 mtx_lock(&Giant); 1245 ktrsysret(p->p_tracep, code, error, p->p_retval[0]); 1246 } 1247 #endif 1248 1249 /* 1250 * This works because errno is findable through the 1251 * register set. If we ever support an emulation where this 1252 * is not the case, this code will need to be revisited. 1253 */ 1254 STOPEVENT(p, S_SCX, code); 1255 1256 /* 1257 * Release Giant if we had to get it 1258 */ 1259 if (mtx_owned(&Giant)) 1260 mtx_unlock(&Giant); 1261 1262 #ifdef WITNESS 1263 if (witness_list(p)) { 1264 panic("system call %s returning with mutex(s) held\n", 1265 syscallnames[code]); 1266 } 1267 #endif 1268 mtx_assert(&sched_lock, MA_NOTOWNED); 1269 mtx_assert(&Giant, MA_NOTOWNED); 1270 } 1271 1272 void 1273 ast(framep) 1274 struct trapframe *framep; 1275 { 1276 struct proc *p = CURPROC; 1277 u_quad_t sticks; 1278 1279 KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode")); 1280 1281 /* 1282 * We check for a pending AST here rather than in the assembly as 1283 * acquiring and releasing mutexes in assembly is not fun. 1284 */ 1285 mtx_lock_spin(&sched_lock); 1286 if (!(astpending(p) || resched_wanted())) { 1287 mtx_unlock_spin(&sched_lock); 1288 return; 1289 } 1290 1291 sticks = p->p_sticks; 1292 p->p_md.md_regs = framep; 1293 1294 astoff(p); 1295 cnt.v_soft++; 1296 mtx_intr_enable(&sched_lock); 1297 if (p->p_sflag & PS_OWEUPC) { 1298 p->p_sflag &= ~PS_OWEUPC; 1299 mtx_unlock_spin(&sched_lock); 1300 mtx_lock(&Giant); 1301 mtx_lock_spin(&sched_lock); 1302 addupc_task(p, p->p_stats->p_prof.pr_addr, 1303 p->p_stats->p_prof.pr_ticks); 1304 } 1305 if (p->p_sflag & PS_ALRMPEND) { 1306 p->p_sflag &= ~PS_ALRMPEND; 1307 mtx_unlock_spin(&sched_lock); 1308 if (!mtx_owned(&Giant)) 1309 mtx_lock(&Giant); 1310 psignal(p, SIGVTALRM); 1311 mtx_lock_spin(&sched_lock); 1312 } 1313 if (p->p_sflag & PS_PROFPEND) { 1314 p->p_sflag &= ~PS_PROFPEND; 1315 mtx_unlock_spin(&sched_lock); 1316 if (!mtx_owned(&Giant)) 1317 mtx_lock(&Giant); 1318 psignal(p, SIGPROF); 1319 } else 1320 mtx_unlock_spin(&sched_lock); 1321 1322 userret(p, framep, sticks); 1323 1324 if (mtx_owned(&Giant)) 1325 mtx_unlock(&Giant); 1326 } 1327