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 1.29 1994/08/18 22:34:43 wollman Exp $ 39 */ 40 41 /* 42 * 386 Trap and System call handling 43 */ 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/proc.h> 48 #include <sys/user.h> 49 #include <sys/acct.h> 50 #include <sys/kernel.h> 51 #include <sys/syscall.h> 52 #include <sys/sysent.h> 53 #ifdef KTRACE 54 #include <sys/ktrace.h> 55 #endif 56 57 #include <vm/vm_param.h> 58 #include <vm/pmap.h> 59 #include <vm/vm_map.h> 60 #include <vm/vm_page.h> 61 62 #include <machine/cpu.h> 63 #include <machine/psl.h> 64 #include <machine/reg.h> 65 #include <machine/eflags.h> 66 #include <machine/trap.h> 67 68 #include "isa.h" 69 #include "npx.h" 70 #include "ddb.h" 71 72 int trap_pfault __P((struct trapframe *, int)); 73 void trap_fatal __P((struct trapframe *)); 74 75 #define MAX_TRAP_MSG 27 76 char *trap_msg[] = { 77 "reserved addressing fault", /* 0 T_RESADFLT */ 78 "privileged instruction fault", /* 1 T_PRIVINFLT */ 79 "reserved operand fault", /* 2 T_RESOPFLT */ 80 "breakpoint instruction fault", /* 3 T_BPTFLT */ 81 "", /* 4 unused */ 82 "system call trap", /* 5 T_SYSCALL */ 83 "arithmetic trap", /* 6 T_ARITHTRAP */ 84 "system forced exception", /* 7 T_ASTFLT */ 85 "segmentation (limit) fault", /* 8 T_SEGFLT */ 86 "general protection fault", /* 9 T_PROTFLT */ 87 "trace trap", /* 10 T_TRCTRAP */ 88 "", /* 11 unused */ 89 "page fault", /* 12 T_PAGEFLT */ 90 "page table fault", /* 13 T_TABLEFLT */ 91 "alignment fault", /* 14 T_ALIGNFLT */ 92 "kernel stack pointer not valid", /* 15 T_KSPNOTVAL */ 93 "bus error", /* 16 T_BUSERR */ 94 "kernel debugger fault", /* 17 T_KDBTRAP */ 95 "integer divide fault", /* 18 T_DIVIDE */ 96 "non-maskable interrupt trap", /* 19 T_NMI */ 97 "overflow trap", /* 20 T_OFLOW */ 98 "FPU bounds check fault", /* 21 T_BOUND */ 99 "FPU device not available", /* 22 T_DNA */ 100 "double fault", /* 23 T_DOUBLEFLT */ 101 "FPU operand fetch fault", /* 24 T_FPOPFLT */ 102 "invalid TSS fault", /* 25 T_TSSFLT */ 103 "segment not present fault", /* 26 T_SEGNPFLT */ 104 "stack fault", /* 27 T_STKFLT */ 105 }; 106 107 static inline void 108 userret(p, frame, oticks) 109 struct proc *p; 110 struct trapframe *frame; 111 u_quad_t oticks; 112 { 113 int sig, s; 114 115 while (sig = CURSIG(p)) 116 postsig(sig); 117 p->p_priority = p->p_usrpri; 118 if (want_resched) { 119 /* 120 * Since we are curproc, clock will normally just change 121 * our priority without moving us from one queue to another 122 * (since the running process is not on a queue.) 123 * If that happened after we setrunqueue ourselves but before we 124 * mi_switch()'ed, we might not be on the queue indicated by 125 * our priority. 126 */ 127 s = splclock(); 128 setrunqueue(p); 129 p->p_stats->p_ru.ru_nivcsw++; 130 mi_switch(); 131 splx(s); 132 while (sig = CURSIG(p)) 133 postsig(sig); 134 } 135 if (p->p_stats->p_prof.pr_scale) { 136 u_quad_t ticks = p->p_sticks - oticks; 137 138 if (ticks) { 139 #ifdef PROFTIMER 140 extern int profscale; 141 addupc(frame->tf_eip, &p->p_stats->p_prof, 142 ticks * profscale); 143 #else 144 addupc(frame->tf_eip, &p->p_stats->p_prof, ticks); 145 #endif 146 } 147 } 148 curpriority = p->p_priority; 149 } 150 151 /* 152 * trap(frame): 153 * Exception, fault, and trap interface to the FreeBSD kernel. 154 * This common code is called from assembly language IDT gate entry 155 * routines that prepare a suitable stack frame, and restore this 156 * frame after the exception has been processed. 157 */ 158 159 /*ARGSUSED*/ 160 void 161 trap(frame) 162 struct trapframe frame; 163 { 164 struct proc *p = curproc; 165 u_quad_t sticks = 0; 166 int i = 0, ucode = 0, type, code, eva, fault_type; 167 168 frame.tf_eflags &= ~PSL_NT; /* clear nested trap XXX */ 169 type = frame.tf_trapno; 170 code = frame.tf_err; 171 172 if (ISPL(frame.tf_cs) == SEL_UPL) { 173 /* user trap */ 174 175 sticks = p->p_sticks; 176 p->p_md.md_regs = (int *)&frame; 177 178 switch (type) { 179 case T_RESADFLT: /* reserved addressing fault */ 180 case T_PRIVINFLT: /* privileged instruction fault */ 181 case T_RESOPFLT: /* reserved operand fault */ 182 ucode = type; 183 i = SIGILL; 184 break; 185 186 case T_BPTFLT: /* bpt instruction fault */ 187 case T_TRCTRAP: /* trace trap */ 188 frame.tf_eflags &= ~PSL_T; 189 i = SIGTRAP; 190 break; 191 192 case T_ARITHTRAP: /* arithmetic trap */ 193 ucode = code; 194 i = SIGFPE; 195 break; 196 197 case T_ASTFLT: /* Allow process switch */ 198 astoff(); 199 cnt.v_soft++; 200 if ((p->p_flag & P_OWEUPC) && p->p_stats->p_prof.pr_scale) { 201 addupc(frame.tf_eip, &p->p_stats->p_prof, 1); 202 p->p_flag &= ~P_OWEUPC; 203 } 204 goto out; 205 206 case T_PROTFLT: /* general protection fault */ 207 case T_SEGNPFLT: /* segment not present fault */ 208 case T_STKFLT: /* stack fault */ 209 ucode = code + BUS_SEGM_FAULT ; 210 i = SIGBUS; 211 break; 212 213 case T_PAGEFLT: /* page fault */ 214 i = trap_pfault(&frame, TRUE); 215 if (i == 0) 216 goto out; 217 218 ucode = T_PAGEFLT; 219 break; 220 221 case T_DIVIDE: /* integer divide fault */ 222 ucode = FPE_INTDIV_TRAP; 223 i = SIGFPE; 224 break; 225 226 #if NISA > 0 227 case T_NMI: 228 #if NDDB > 0 229 /* NMI can be hooked up to a pushbutton for debugging */ 230 printf ("NMI ... going to debugger\n"); 231 if (kdb_trap (type, 0, &frame)) 232 return; 233 #endif 234 /* machine/parity/power fail/"kitchen sink" faults */ 235 if (isa_nmi(code) == 0) return; 236 panic("NMI indicates hardware failure"); 237 #endif 238 239 case T_OFLOW: /* integer overflow fault */ 240 ucode = FPE_INTOVF_TRAP; 241 i = SIGFPE; 242 break; 243 244 case T_BOUND: /* bounds check fault */ 245 ucode = FPE_SUBRNG_TRAP; 246 i = SIGFPE; 247 break; 248 249 case T_DNA: 250 #if NNPX > 0 251 /* if a transparent fault (due to context switch "late") */ 252 if (npxdna()) 253 return; 254 #endif /* NNPX > 0 */ 255 256 #if defined(MATH_EMULATE) || defined(GPL_MATH_EMULATE) 257 i = math_emulate(&frame); 258 if (i == 0) return; 259 #else /* MATH_EMULATE || GPL_MATH_EMULATE */ 260 panic("trap: math emulation necessary!"); 261 #endif /* MATH_EMULATE || GPL_MATH_EMULATE */ 262 ucode = FPE_FPU_NP_TRAP; 263 break; 264 265 case T_FPOPFLT: /* FPU operand fetch fault */ 266 ucode = T_FPOPFLT; 267 i = SIGILL; 268 break; 269 270 default: 271 trap_fatal(&frame); 272 } 273 } else { 274 /* kernel trap */ 275 276 switch (type) { 277 case T_PAGEFLT: /* page fault */ 278 (void) trap_pfault(&frame, FALSE); 279 return; 280 281 case T_PROTFLT: /* general protection fault */ 282 case T_SEGNPFLT: /* segment not present fault */ 283 if (curpcb && curpcb->pcb_onfault) { 284 frame.tf_eip = (int)curpcb->pcb_onfault; 285 return; 286 } 287 break; 288 289 #if NDDB > 0 290 case T_BPTFLT: 291 case T_TRCTRAP: 292 if (kdb_trap (type, 0, &frame)) 293 return; 294 break; 295 #else 296 case T_TRCTRAP: /* trace trap -- someone single stepping lcall's */ 297 /* Q: how do we turn it on again? */ 298 frame.tf_eflags &= ~PSL_T; 299 return; 300 #endif 301 302 #if NISA > 0 303 case T_NMI: 304 #if NDDB > 0 305 /* NMI can be hooked up to a pushbutton for debugging */ 306 printf ("NMI ... going to debugger\n"); 307 if (kdb_trap (type, 0, &frame)) 308 return; 309 #endif 310 /* machine/parity/power fail/"kitchen sink" faults */ 311 if (isa_nmi(code) == 0) return; 312 /* FALL THROUGH */ 313 #endif 314 } 315 316 trap_fatal(&frame); 317 } 318 319 trapsignal(p, i, ucode); 320 321 #ifdef DIAGNOSTIC 322 eva = rcr2(); 323 if (type <= MAX_TRAP_MSG) { 324 uprintf("fatal process exception: %s", 325 trap_msg[type]); 326 if ((type == T_PAGEFLT) || (type == T_PROTFLT)) 327 uprintf(", fault VA = 0x%x", eva); 328 uprintf("\n"); 329 } 330 #endif 331 332 out: 333 userret(p, &frame, sticks); 334 } 335 336 int 337 trap_pfault(frame, usermode) 338 struct trapframe *frame; 339 int usermode; 340 { 341 vm_offset_t va; 342 struct vmspace *vm; 343 vm_map_t map = 0; 344 int rv = 0, oldflags; 345 vm_prot_t ftype; 346 extern vm_map_t kernel_map; 347 int eva; 348 struct proc *p = curproc; 349 350 eva = rcr2(); 351 va = trunc_page((vm_offset_t)eva); 352 353 /* 354 * Don't allow user-mode faults in kernel address space 355 */ 356 if (usermode && (va >= KERNBASE)) { 357 goto nogo; 358 } 359 360 if ((p == 0) || (va >= KERNBASE)) { 361 vm = 0; 362 map = kernel_map; 363 } else { 364 vm = p->p_vmspace; 365 map = &vm->vm_map; 366 } 367 368 if (frame->tf_err & PGEX_W) 369 ftype = VM_PROT_READ | VM_PROT_WRITE; 370 else 371 ftype = VM_PROT_READ; 372 373 if (map != kernel_map) { 374 vm_offset_t pa; 375 vm_offset_t v = (vm_offset_t) vtopte(va); 376 vm_page_t ptepg; 377 378 /* 379 * Keep swapout from messing with us during this 380 * critical time. 381 */ 382 ++p->p_lock; 383 384 /* 385 * Grow the stack if necessary 386 */ 387 if ((caddr_t)va > vm->vm_maxsaddr 388 && (caddr_t)va < (caddr_t)USRSTACK) { 389 if (!grow(p, va)) { 390 rv = KERN_FAILURE; 391 --p->p_lock; 392 goto nogo; 393 } 394 } 395 396 /* 397 * Check if page table is mapped, if not, 398 * fault it first 399 */ 400 401 /* Fault the pte only if needed: */ 402 *(volatile char *)v += 0; 403 404 ptepg = (vm_page_t) pmap_pte_vm_page(vm_map_pmap(map), v); 405 if( ptepg->hold_count == 0) 406 ptepg->act_count += 3; 407 vm_page_hold(ptepg); 408 409 /* Fault in the user page: */ 410 rv = vm_fault(map, va, ftype, FALSE); 411 412 vm_page_unhold(ptepg); 413 414 /* 415 * page table pages don't need to be kept if they 416 * are not held 417 */ 418 if( ptepg->hold_count == 0 && ptepg->wire_count == 0) { 419 pmap_page_protect( VM_PAGE_TO_PHYS(ptepg), 420 VM_PROT_NONE); 421 vm_page_free(ptepg); 422 } 423 424 --p->p_lock; 425 } else { 426 /* 427 * Since we know that kernel virtual address addresses 428 * always have pte pages mapped, we just have to fault 429 * the page. 430 */ 431 rv = vm_fault(map, va, ftype, FALSE); 432 } 433 434 if (rv == KERN_SUCCESS) 435 return (0); 436 nogo: 437 if (!usermode) { 438 if (curpcb->pcb_onfault) { 439 frame->tf_eip = (int)curpcb->pcb_onfault; 440 return (0); 441 } 442 trap_fatal(frame); 443 } 444 445 /* kludge to pass faulting virtual address to sendsig */ 446 frame->tf_err = eva; 447 448 return((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV); 449 } 450 451 void 452 trap_fatal(frame) 453 struct trapframe *frame; 454 { 455 int code, type, eva; 456 457 code = frame->tf_err; 458 type = frame->tf_trapno; 459 eva = rcr2(); 460 461 if (type <= MAX_TRAP_MSG) 462 printf("\n\nFatal trap %d: %s while in %s mode\n", 463 type, trap_msg[type], 464 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel"); 465 if (type == T_PAGEFLT) { 466 printf("fault virtual address = 0x%x\n", eva); 467 printf("fault code = %s %s, %s\n", 468 code & PGEX_U ? "user" : "supervisor", 469 code & PGEX_W ? "write" : "read", 470 code & PGEX_P ? "protection violation" : "page not present"); 471 } 472 printf("instruction pointer = 0x%x\n", frame->tf_eip); 473 printf("processor eflags = "); 474 if (frame->tf_eflags & EFL_TF) 475 printf("trace/trap, "); 476 if (frame->tf_eflags & EFL_IF) 477 printf("interrupt enabled, "); 478 if (frame->tf_eflags & EFL_NT) 479 printf("nested task, "); 480 if (frame->tf_eflags & EFL_RF) 481 printf("resume, "); 482 if (frame->tf_eflags & EFL_VM) 483 printf("vm86, "); 484 printf("IOPL = %d\n", (frame->tf_eflags & EFL_IOPL) >> 12); 485 printf("current process = "); 486 if (curproc) { 487 printf("%d (%s)\n", 488 curproc->p_pid, curproc->p_comm ? 489 curproc->p_comm : ""); 490 } else { 491 printf("Idle\n"); 492 } 493 printf("interrupt mask = "); 494 if ((cpl & net_imask) == net_imask) 495 printf("net "); 496 if ((cpl & tty_imask) == tty_imask) 497 printf("tty "); 498 if ((cpl & bio_imask) == bio_imask) 499 printf("bio "); 500 if (cpl == 0) 501 printf("none"); 502 printf("\n"); 503 504 #ifdef KDB 505 if (kdb_trap(&psl)) 506 return; 507 #endif 508 #if NDDB > 0 509 if (kdb_trap (type, 0, frame)) 510 return; 511 #endif 512 if (type <= MAX_TRAP_MSG) 513 panic(trap_msg[type]); 514 else 515 panic("unknown/reserved trap"); 516 } 517 518 /* 519 * Compensate for 386 brain damage (missing URKR). 520 * This is a little simpler than the pagefault handler in trap() because 521 * it the page tables have already been faulted in and high addresses 522 * are thrown out early for other reasons. 523 */ 524 int trapwrite(addr) 525 unsigned addr; 526 { 527 struct proc *p; 528 vm_offset_t va, v; 529 struct vmspace *vm; 530 int oldflags; 531 int rv; 532 533 va = trunc_page((vm_offset_t)addr); 534 /* 535 * XXX - MAX is END. Changed > to >= for temp. fix. 536 */ 537 if (va >= VM_MAXUSER_ADDRESS) 538 return (1); 539 540 p = curproc; 541 vm = p->p_vmspace; 542 543 ++p->p_lock; 544 545 if ((caddr_t)va >= vm->vm_maxsaddr 546 && (caddr_t)va < (caddr_t)USRSTACK) { 547 if (!grow(p, va)) { 548 --p->p_lock; 549 return (1); 550 } 551 } 552 553 v = trunc_page(vtopte(va)); 554 555 /* 556 * wire the pte page 557 */ 558 if (va < USRSTACK) { 559 vm_map_pageable(&vm->vm_map, v, round_page(v+1), FALSE); 560 } 561 562 /* 563 * fault the data page 564 */ 565 rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, FALSE); 566 567 /* 568 * unwire the pte page 569 */ 570 if (va < USRSTACK) { 571 vm_map_pageable(&vm->vm_map, v, round_page(v+1), TRUE); 572 } 573 574 --p->p_lock; 575 576 if (rv != KERN_SUCCESS) 577 return 1; 578 579 return (0); 580 } 581 582 /* 583 * syscall(frame): 584 * System call request from POSIX system call gate interface to kernel. 585 * Like trap(), argument is call by reference. 586 */ 587 /*ARGSUSED*/ 588 void 589 syscall(frame) 590 struct trapframe frame; 591 { 592 caddr_t params; 593 int i; 594 struct sysent *callp; 595 struct proc *p = curproc; 596 u_quad_t sticks; 597 int error, opc; 598 int args[8], rval[2]; 599 u_int code; 600 601 sticks = p->p_sticks; 602 if (ISPL(frame.tf_cs) != SEL_UPL) 603 panic("syscall"); 604 605 code = frame.tf_eax; 606 p->p_md.md_regs = (int *)&frame; 607 params = (caddr_t)frame.tf_esp + sizeof (int) ; 608 609 /* 610 * Reconstruct pc, assuming lcall $X,y is 7 bytes, as it is always. 611 */ 612 opc = frame.tf_eip - 7; 613 /* 614 * Need to check if this is a 32 bit or 64 bit syscall. 615 */ 616 if (code == SYS_syscall) { 617 /* 618 * Code is first argument, followed by actual args. 619 */ 620 code = fuword(params); 621 params += sizeof (int); 622 } else if (code == SYS___syscall) { 623 /* 624 * Like syscall, but code is a quad, so as to maintain 625 * quad alignment for the rest of the arguments. 626 */ 627 code = fuword(params + _QUAD_LOWWORD * sizeof(int)); 628 params += sizeof(quad_t); 629 } 630 631 if (p->p_sysent->sv_mask) 632 code = code & p->p_sysent->sv_mask; 633 634 if (code < 0 || code >= p->p_sysent->sv_size) 635 callp = &p->p_sysent->sv_table[0]; 636 else 637 callp = &p->p_sysent->sv_table[code]; 638 639 if ((i = callp->sy_narg * sizeof (int)) && 640 (error = copyin(params, (caddr_t)args, (u_int)i))) { 641 #ifdef KTRACE 642 if (KTRPOINT(p, KTR_SYSCALL)) 643 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 644 #endif 645 goto bad; 646 } 647 #ifdef KTRACE 648 if (KTRPOINT(p, KTR_SYSCALL)) 649 ktrsyscall(p->p_tracep, code, callp->sy_narg, args); 650 #endif 651 rval[0] = 0; 652 rval[1] = frame.tf_edx; 653 654 error = (*callp->sy_call)(p, args, rval); 655 656 switch (error) { 657 658 case 0: 659 /* 660 * Reinitialize proc pointer `p' as it may be different 661 * if this is a child returning from fork syscall. 662 */ 663 p = curproc; 664 frame.tf_eax = rval[0]; 665 frame.tf_edx = rval[1]; 666 frame.tf_eflags &= ~PSL_C; /* carry bit */ 667 break; 668 669 case ERESTART: 670 frame.tf_eip = opc; 671 break; 672 673 case EJUSTRETURN: 674 break; 675 676 default: 677 bad: 678 frame.tf_eax = error; 679 frame.tf_eflags |= PSL_C; /* carry bit */ 680 break; 681 } 682 683 userret(p, &frame, sticks); 684 685 #ifdef KTRACE 686 if (KTRPOINT(p, KTR_SYSRET)) 687 ktrsysret(p->p_tracep, code, error, rval[0]); 688 #endif 689 } 690