1 /* $NetBSD: fault.c,v 1.74 2010/01/05 13:14:55 mbalmer Exp $ */ 2 3 /* 4 * Copyright 2003 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Steve C. Woodford for Wasabi Systems, Inc. 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 for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 /* 38 * Copyright (c) 1994-1997 Mark Brinicombe. 39 * Copyright (c) 1994 Brini. 40 * All rights reserved. 41 * 42 * This code is derived from software written for Brini by Mark Brinicombe 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. All advertising materials mentioning features or use of this software 53 * must display the following acknowledgement: 54 * This product includes software developed by Brini. 55 * 4. The name of the company nor the name of the author may be used to 56 * endorse or promote products derived from this software without specific 57 * prior written permission. 58 * 59 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED 60 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 61 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 62 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 63 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 64 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 65 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 66 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 67 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 68 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 69 * SUCH DAMAGE. 70 * 71 * RiscBSD kernel project 72 * 73 * fault.c 74 * 75 * Fault handlers 76 * 77 * Created : 28/11/94 78 */ 79 80 #include "opt_ddb.h" 81 #include "opt_kgdb.h" 82 #include "opt_sa.h" 83 84 #include <sys/types.h> 85 __KERNEL_RCSID(0, "$NetBSD: fault.c,v 1.74 2010/01/05 13:14:55 mbalmer Exp $"); 86 87 #include <sys/param.h> 88 #include <sys/systm.h> 89 #include <sys/proc.h> 90 #include <sys/kernel.h> 91 #include <sys/kauth.h> 92 93 #include <sys/savar.h> 94 #include <sys/cpu.h> 95 96 #include <uvm/uvm_extern.h> 97 #include <uvm/uvm_stat.h> 98 #ifdef UVMHIST 99 #include <uvm/uvm.h> 100 #endif 101 102 #include <arm/cpuconf.h> 103 104 #include <machine/frame.h> 105 #include <arm/arm32/katelib.h> 106 #include <machine/intr.h> 107 #if defined(DDB) || defined(KGDB) 108 #include <machine/db_machdep.h> 109 #ifdef KGDB 110 #include <sys/kgdb.h> 111 #endif 112 #if !defined(DDB) 113 #define kdb_trap kgdb_trap 114 #endif 115 #endif 116 117 #include <arch/arm/arm/disassem.h> 118 #include <arm/arm32/machdep.h> 119 120 extern char fusubailout[]; 121 122 #ifdef DEBUG 123 int last_fault_code; /* For the benefit of pmap_fault_fixup() */ 124 #endif 125 126 #if defined(CPU_ARM3) || defined(CPU_ARM6) || \ 127 defined(CPU_ARM7) || defined(CPU_ARM7TDMI) 128 /* These CPUs may need data/prefetch abort fixups */ 129 #define CPU_ABORT_FIXUP_REQUIRED 130 #endif 131 132 struct data_abort { 133 int (*func)(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 134 const char *desc; 135 }; 136 137 static int dab_fatal(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 138 static int dab_align(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 139 static int dab_buserr(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 140 141 static const struct data_abort data_aborts[] = { 142 {dab_fatal, "Vector Exception"}, 143 {dab_align, "Alignment Fault 1"}, 144 {dab_fatal, "Terminal Exception"}, 145 {dab_align, "Alignment Fault 3"}, 146 {dab_buserr, "External Linefetch Abort (S)"}, 147 {NULL, "Translation Fault (S)"}, 148 {dab_buserr, "External Linefetch Abort (P)"}, 149 {NULL, "Translation Fault (P)"}, 150 {dab_buserr, "External Non-Linefetch Abort (S)"}, 151 {NULL, "Domain Fault (S)"}, 152 {dab_buserr, "External Non-Linefetch Abort (P)"}, 153 {NULL, "Domain Fault (P)"}, 154 {dab_buserr, "External Translation Abort (L1)"}, 155 {NULL, "Permission Fault (S)"}, 156 {dab_buserr, "External Translation Abort (L2)"}, 157 {NULL, "Permission Fault (P)"} 158 }; 159 160 /* Determine if a fault came from user mode */ 161 #define TRAP_USERMODE(tf) ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE) 162 163 /* Determine if 'x' is a permission fault */ 164 #define IS_PERMISSION_FAULT(x) \ 165 (((1 << ((x) & FAULT_TYPE_MASK)) & \ 166 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) 167 168 #if 0 169 /* maybe one day we'll do emulations */ 170 #define TRAPSIGNAL(l,k) (*(l)->l_proc->p_emul->e_trapsignal)((l), (k)) 171 #else 172 #define TRAPSIGNAL(l,k) trapsignal((l), (k)) 173 #endif 174 175 static inline void 176 call_trapsignal(struct lwp *l, ksiginfo_t *ksi) 177 { 178 179 TRAPSIGNAL(l, ksi); 180 } 181 182 static inline int 183 data_abort_fixup(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l) 184 { 185 #ifdef CPU_ABORT_FIXUP_REQUIRED 186 int error; 187 188 /* Call the CPU specific data abort fixup routine */ 189 error = cpu_dataabt_fixup(tf); 190 if (__predict_true(error != ABORT_FIXUP_FAILED)) 191 return (error); 192 193 /* 194 * Oops, couldn't fix up the instruction 195 */ 196 printf("data_abort_fixup: fixup for %s mode data abort failed.\n", 197 TRAP_USERMODE(tf) ? "user" : "kernel"); 198 #ifdef THUMB_CODE 199 if (tf->tf_spsr & PSR_T_bit) { 200 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 201 tf->tf_pc, *((u_int16 *)(tf->tf_pc & ~1)), 202 *((u_int16 *)((tf->tf_pc + 2) & ~1))); 203 } 204 else 205 #endif 206 { 207 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 208 *((u_int *)tf->tf_pc)); 209 } 210 disassemble(tf->tf_pc); 211 212 /* Die now if this happened in kernel mode */ 213 if (!TRAP_USERMODE(tf)) 214 dab_fatal(tf, fsr, far, l, NULL); 215 216 return (error); 217 #else 218 return (ABORT_FIXUP_OK); 219 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 220 } 221 222 void 223 data_abort_handler(trapframe_t *tf) 224 { 225 struct vm_map *map; 226 struct pcb *pcb; 227 struct lwp *l; 228 u_int user, far, fsr; 229 vm_prot_t ftype; 230 void *onfault; 231 vaddr_t va; 232 int error; 233 ksiginfo_t ksi; 234 235 UVMHIST_FUNC("data_abort_handler"); 236 237 /* Grab FAR/FSR before enabling interrupts */ 238 far = cpu_faultaddress(); 239 fsr = cpu_faultstatus(); 240 241 UVMHIST_CALLED(maphist); 242 /* Update vmmeter statistics */ 243 uvmexp.traps++; 244 245 /* Re-enable interrupts if they were enabled previously */ 246 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 247 if (__predict_true((tf->tf_spsr & IF32_bits) != IF32_bits)) 248 restore_interrupts(tf->tf_spsr & IF32_bits); 249 250 /* Get the current lwp structure */ 251 KASSERT(curlwp != NULL); 252 l = curlwp; 253 254 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, far=0x%x, fsr=0x%x)", 255 tf->tf_pc, l, far, fsr); 256 257 /* Data abort came from user mode? */ 258 if ((user = TRAP_USERMODE(tf)) != 0) 259 LWP_CACHE_CREDS(l, l->l_proc); 260 261 /* Grab the current pcb */ 262 pcb = lwp_getpcb(l); 263 264 /* Invoke the appropriate handler, if necessary */ 265 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 266 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, 267 l, &ksi)) 268 goto do_trapsignal; 269 goto out; 270 } 271 272 /* 273 * At this point, we're dealing with one of the following data aborts: 274 * 275 * FAULT_TRANS_S - Translation -- Section 276 * FAULT_TRANS_P - Translation -- Page 277 * FAULT_DOMAIN_S - Domain -- Section 278 * FAULT_DOMAIN_P - Domain -- Page 279 * FAULT_PERM_S - Permission -- Section 280 * FAULT_PERM_P - Permission -- Page 281 * 282 * These are the main virtual memory-related faults signalled by 283 * the MMU. 284 */ 285 286 /* fusubailout is used by [fs]uswintr to avoid page faulting */ 287 if (__predict_false(pcb->pcb_onfault == fusubailout)) { 288 tf->tf_r0 = EFAULT; 289 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 290 return; 291 } 292 293 if (user) { 294 pcb->pcb_tf = tf; 295 } 296 297 /* 298 * Make sure the Program Counter is sane. We could fall foul of 299 * someone executing Thumb code, in which case the PC might not 300 * be word-aligned. This would cause a kernel alignment fault 301 * further down if we have to decode the current instruction. 302 */ 303 #ifdef THUMB_CODE 304 /* 305 * XXX: It would be nice to be able to support Thumb in the kernel 306 * at some point. 307 */ 308 if (__predict_false(!user && (tf->tf_pc & 3) != 0)) { 309 printf("\ndata_abort_fault: Misaligned Kernel-mode " 310 "Program Counter\n"); 311 dab_fatal(tf, fsr, far, l, NULL); 312 } 313 #else 314 if (__predict_false((tf->tf_pc & 3) != 0)) { 315 if (user) { 316 /* 317 * Give the user an illegal instruction signal. 318 */ 319 /* Deliver a SIGILL to the process */ 320 KSI_INIT_TRAP(&ksi); 321 ksi.ksi_signo = SIGILL; 322 ksi.ksi_code = ILL_ILLOPC; 323 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 324 ksi.ksi_trap = fsr; 325 goto do_trapsignal; 326 } 327 328 /* 329 * The kernel never executes Thumb code. 330 */ 331 printf("\ndata_abort_fault: Misaligned Kernel-mode " 332 "Program Counter\n"); 333 dab_fatal(tf, fsr, far, l, NULL); 334 } 335 #endif 336 337 /* See if the CPU state needs to be fixed up */ 338 switch (data_abort_fixup(tf, fsr, far, l)) { 339 case ABORT_FIXUP_RETURN: 340 return; 341 case ABORT_FIXUP_FAILED: 342 /* Deliver a SIGILL to the process */ 343 KSI_INIT_TRAP(&ksi); 344 ksi.ksi_signo = SIGILL; 345 ksi.ksi_code = ILL_ILLOPC; 346 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 347 ksi.ksi_trap = fsr; 348 goto do_trapsignal; 349 default: 350 break; 351 } 352 353 va = trunc_page((vaddr_t)far); 354 355 /* 356 * It is only a kernel address space fault iff: 357 * 1. user == 0 and 358 * 2. pcb_onfault not set or 359 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. 360 */ 361 if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS || 362 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && 363 __predict_true((pcb->pcb_onfault == NULL || 364 (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) { 365 map = kernel_map; 366 367 /* Was the fault due to the FPE/IPKDB ? */ 368 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { 369 KSI_INIT_TRAP(&ksi); 370 ksi.ksi_signo = SIGSEGV; 371 ksi.ksi_code = SEGV_ACCERR; 372 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 373 ksi.ksi_trap = fsr; 374 375 /* 376 * Force exit via userret() 377 * This is necessary as the FPE is an extension to 378 * userland that actually runs in a priveledged mode 379 * but uses USR mode permissions for its accesses. 380 */ 381 user = 1; 382 goto do_trapsignal; 383 } 384 } else { 385 map = &l->l_proc->p_vmspace->vm_map; 386 #ifdef KERN_SA 387 if ((l->l_flag & LW_SA) && (~l->l_pflag & LP_SA_NOBLOCK)) { 388 l->l_savp->savp_faultaddr = (vaddr_t)far; 389 l->l_pflag |= LP_SA_PAGEFAULT; 390 } 391 #endif 392 } 393 394 /* 395 * We need to know whether the page should be mapped 396 * as R or R/W. The MMU does not give us the info as 397 * to whether the fault was caused by a read or a write. 398 * 399 * However, we know that a permission fault can only be 400 * the result of a write to a read-only location, so 401 * we can deal with those quickly. 402 * 403 * Otherwise we need to disassemble the instruction 404 * responsible to determine if it was a write. 405 */ 406 if (IS_PERMISSION_FAULT(fsr)) 407 ftype = VM_PROT_WRITE; 408 else { 409 #ifdef THUMB_CODE 410 /* Fast track the ARM case. */ 411 if (__predict_false(tf->tf_spsr & PSR_T_bit)) { 412 u_int insn = fusword((void *)(tf->tf_pc & ~1)); 413 u_int insn_f8 = insn & 0xf800; 414 u_int insn_fe = insn & 0xfe00; 415 416 if (insn_f8 == 0x6000 || /* STR(1) */ 417 insn_f8 == 0x7000 || /* STRB(1) */ 418 insn_f8 == 0x8000 || /* STRH(1) */ 419 insn_f8 == 0x9000 || /* STR(3) */ 420 insn_f8 == 0xc000 || /* STM */ 421 insn_fe == 0x5000 || /* STR(2) */ 422 insn_fe == 0x5200 || /* STRH(2) */ 423 insn_fe == 0x5400) /* STRB(2) */ 424 ftype = VM_PROT_WRITE; 425 else 426 ftype = VM_PROT_READ; 427 } 428 else 429 #endif 430 { 431 u_int insn = ReadWord(tf->tf_pc); 432 433 if (((insn & 0x0c100000) == 0x04000000) || /* STR[B] */ 434 ((insn & 0x0e1000b0) == 0x000000b0) || /* STR[HD]*/ 435 ((insn & 0x0a100000) == 0x08000000)) /* STM/CDT*/ 436 ftype = VM_PROT_WRITE; 437 else if ((insn & 0x0fb00ff0) == 0x01000090)/* SWP */ 438 ftype = VM_PROT_READ | VM_PROT_WRITE; 439 else 440 ftype = VM_PROT_READ; 441 } 442 } 443 444 /* 445 * See if the fault is as a result of ref/mod emulation, 446 * or domain mismatch. 447 */ 448 #ifdef DEBUG 449 last_fault_code = fsr; 450 #endif 451 if (pmap_fault_fixup(map->pmap, va, ftype, user)) { 452 #ifdef KERN_SA 453 if (map != kernel_map) 454 l->l_pflag &= ~LP_SA_PAGEFAULT; 455 #endif 456 UVMHIST_LOG(maphist, " <- ref/mod emul", 0, 0, 0, 0); 457 goto out; 458 } 459 460 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 461 if (pcb->pcb_onfault) { 462 tf->tf_r0 = EINVAL; 463 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 464 return; 465 } 466 printf("\nNon-emulated page fault with intr_depth > 0\n"); 467 dab_fatal(tf, fsr, far, l, NULL); 468 } 469 470 onfault = pcb->pcb_onfault; 471 pcb->pcb_onfault = NULL; 472 error = uvm_fault(map, va, ftype); 473 pcb->pcb_onfault = onfault; 474 475 #ifdef KERN_SA 476 if (map != kernel_map) 477 l->l_pflag &= ~LP_SA_PAGEFAULT; 478 #endif 479 480 if (__predict_true(error == 0)) { 481 if (user) 482 uvm_grow(l->l_proc, va); /* Record any stack growth */ 483 UVMHIST_LOG(maphist, " <- uvm", 0, 0, 0, 0); 484 goto out; 485 } 486 487 if (user == 0) { 488 if (pcb->pcb_onfault) { 489 tf->tf_r0 = error; 490 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 491 return; 492 } 493 494 printf("\nuvm_fault(%p, %lx, %x) -> %x\n", map, va, ftype, 495 error); 496 dab_fatal(tf, fsr, far, l, NULL); 497 } 498 499 KSI_INIT_TRAP(&ksi); 500 501 if (error == ENOMEM) { 502 printf("UVM: pid %d (%s), uid %d killed: " 503 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 504 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 505 ksi.ksi_signo = SIGKILL; 506 } else 507 ksi.ksi_signo = SIGSEGV; 508 509 ksi.ksi_code = (error == EACCES) ? SEGV_ACCERR : SEGV_MAPERR; 510 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 511 ksi.ksi_trap = fsr; 512 UVMHIST_LOG(maphist, " <- error (%d)", error, 0, 0, 0); 513 514 do_trapsignal: 515 call_trapsignal(l, &ksi); 516 out: 517 /* If returning to user mode, make sure to invoke userret() */ 518 if (user) 519 userret(l); 520 } 521 522 /* 523 * dab_fatal() handles the following data aborts: 524 * 525 * FAULT_WRTBUF_0 - Vector Exception 526 * FAULT_WRTBUF_1 - Terminal Exception 527 * 528 * We should never see these on a properly functioning system. 529 * 530 * This function is also called by the other handlers if they 531 * detect a fatal problem. 532 * 533 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 534 */ 535 static int 536 dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 537 { 538 const char *mode; 539 540 mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 541 542 if (l != NULL) { 543 printf("Fatal %s mode data abort: '%s'\n", mode, 544 data_aborts[fsr & FAULT_TYPE_MASK].desc); 545 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 546 if ((fsr & FAULT_IMPRECISE) == 0) 547 printf("%08x, ", far); 548 else 549 printf("Invalid, "); 550 printf("spsr=%08x\n", tf->tf_spsr); 551 } else { 552 printf("Fatal %s mode prefetch abort at 0x%08x\n", 553 mode, tf->tf_pc); 554 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 555 } 556 557 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 558 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 559 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 560 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 561 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 562 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 563 printf("r12=%08x, ", tf->tf_r12); 564 565 if (TRAP_USERMODE(tf)) 566 printf("usp=%08x, ulr=%08x", 567 tf->tf_usr_sp, tf->tf_usr_lr); 568 else 569 printf("ssp=%08x, slr=%08x", 570 tf->tf_svc_sp, tf->tf_svc_lr); 571 printf(", pc =%08x\n\n", tf->tf_pc); 572 573 #if defined(DDB) || defined(KGDB) 574 kdb_trap(T_FAULT, tf); 575 #endif 576 panic("Fatal abort"); 577 /*NOTREACHED*/ 578 } 579 580 /* 581 * dab_align() handles the following data aborts: 582 * 583 * FAULT_ALIGN_0 - Alignment fault 584 * FAULT_ALIGN_0 - Alignment fault 585 * 586 * These faults are fatal if they happen in kernel mode. Otherwise, we 587 * deliver a bus error to the process. 588 */ 589 static int 590 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 591 { 592 struct pcb *pcb = lwp_getpcb(l); 593 594 /* Alignment faults are always fatal if they occur in kernel mode */ 595 if (!TRAP_USERMODE(tf)) 596 dab_fatal(tf, fsr, far, l, NULL); 597 598 /* pcb_onfault *must* be NULL at this point */ 599 KDASSERT(pcb->pcb_onfault == NULL); 600 601 /* See if the CPU state needs to be fixed up */ 602 (void) data_abort_fixup(tf, fsr, far, l); 603 604 /* Deliver a bus error signal to the process */ 605 KSI_INIT_TRAP(ksi); 606 ksi->ksi_signo = SIGBUS; 607 ksi->ksi_code = BUS_ADRALN; 608 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 609 ksi->ksi_trap = fsr; 610 611 pcb->pcb_tf = tf; 612 613 return (1); 614 } 615 616 /* 617 * dab_buserr() handles the following data aborts: 618 * 619 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 620 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 621 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 622 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 623 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 624 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 625 * 626 * If pcb_onfault is set, flag the fault and return to the handler. 627 * If the fault occurred in user mode, give the process a SIGBUS. 628 * 629 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 630 * can be flagged as imprecise in the FSR. This causes a real headache 631 * since some of the machine state is lost. In this case, tf->tf_pc 632 * may not actually point to the offending instruction. In fact, if 633 * we've taken a double abort fault, it generally points somewhere near 634 * the top of "data_abort_entry" in exception.S. 635 * 636 * In all other cases, these data aborts are considered fatal. 637 */ 638 static int 639 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 640 ksiginfo_t *ksi) 641 { 642 struct pcb *pcb = lwp_getpcb(l); 643 644 #ifdef __XSCALE__ 645 if ((fsr & FAULT_IMPRECISE) != 0 && 646 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 647 /* 648 * Oops, an imprecise, double abort fault. We've lost the 649 * r14_abt/spsr_abt values corresponding to the original 650 * abort, and the spsr saved in the trapframe indicates 651 * ABT mode. 652 */ 653 tf->tf_spsr &= ~PSR_MODE; 654 655 /* 656 * We use a simple heuristic to determine if the double abort 657 * happened as a result of a kernel or user mode access. 658 * If the current trapframe is at the top of the kernel stack, 659 * the fault _must_ have come from user mode. 660 */ 661 if (tf != ((trapframe_t *)pcb->pcb_un.un_32.pcb32_sp) - 1) { 662 /* 663 * Kernel mode. We're either about to die a 664 * spectacular death, or pcb_onfault will come 665 * to our rescue. Either way, the current value 666 * of tf->tf_pc is irrelevant. 667 */ 668 tf->tf_spsr |= PSR_SVC32_MODE; 669 if (pcb->pcb_onfault == NULL) 670 printf("\nKernel mode double abort!\n"); 671 } else { 672 /* 673 * User mode. We've lost the program counter at the 674 * time of the fault (not that it was accurate anyway; 675 * it's not called an imprecise fault for nothing). 676 * About all we can do is copy r14_usr to tf_pc and 677 * hope for the best. The process is about to get a 678 * SIGBUS, so it's probably history anyway. 679 */ 680 tf->tf_spsr |= PSR_USR32_MODE; 681 tf->tf_pc = tf->tf_usr_lr; 682 #ifdef THUMB_CODE 683 tf->tf_spsr &= ~PSR_T_bit; 684 if (tf->tf_usr_lr & 1) 685 tf->tf_spsr |= PSR_T_bit; 686 #endif 687 } 688 } 689 690 /* FAR is invalid for imprecise exceptions */ 691 if ((fsr & FAULT_IMPRECISE) != 0) 692 far = 0; 693 #endif /* __XSCALE__ */ 694 695 if (pcb->pcb_onfault) { 696 KDASSERT(TRAP_USERMODE(tf) == 0); 697 tf->tf_r0 = EFAULT; 698 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 699 return (0); 700 } 701 702 /* See if the CPU state needs to be fixed up */ 703 (void) data_abort_fixup(tf, fsr, far, l); 704 705 /* 706 * At this point, if the fault happened in kernel mode, we're toast 707 */ 708 if (!TRAP_USERMODE(tf)) 709 dab_fatal(tf, fsr, far, l, NULL); 710 711 /* Deliver a bus error signal to the process */ 712 KSI_INIT_TRAP(ksi); 713 ksi->ksi_signo = SIGBUS; 714 ksi->ksi_code = BUS_ADRERR; 715 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 716 ksi->ksi_trap = fsr; 717 718 pcb->pcb_tf = tf; 719 720 return (1); 721 } 722 723 static inline int 724 prefetch_abort_fixup(trapframe_t *tf) 725 { 726 #ifdef CPU_ABORT_FIXUP_REQUIRED 727 int error; 728 729 /* Call the CPU specific prefetch abort fixup routine */ 730 error = cpu_prefetchabt_fixup(tf); 731 if (__predict_true(error != ABORT_FIXUP_FAILED)) 732 return (error); 733 734 /* 735 * Oops, couldn't fix up the instruction 736 */ 737 printf( 738 "prefetch_abort_fixup: fixup for %s mode prefetch abort failed.\n", 739 TRAP_USERMODE(tf) ? "user" : "kernel"); 740 #ifdef THUMB_CODE 741 if (tf->tf_spsr & PSR_T_bit) { 742 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 743 tf->tf_pc, *((u_int16 *)(tf->tf_pc & ~1), 744 *((u_int16 *)((tf->tf_pc + 2) & ~1)); 745 } 746 else 747 #endif 748 { 749 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 750 *((u_int *)tf->tf_pc)); 751 } 752 disassemble(tf->tf_pc); 753 754 /* Die now if this happened in kernel mode */ 755 if (!TRAP_USERMODE(tf)) 756 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 757 758 return (error); 759 #else 760 return (ABORT_FIXUP_OK); 761 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 762 } 763 764 /* 765 * void prefetch_abort_handler(trapframe_t *tf) 766 * 767 * Abort handler called when instruction execution occurs at 768 * a non existent or restricted (access permissions) memory page. 769 * If the address is invalid and we were in SVC mode then panic as 770 * the kernel should never prefetch abort. 771 * If the address is invalid and the page is mapped then the user process 772 * does no have read permission so send it a signal. 773 * Otherwise fault the page in and try again. 774 */ 775 void 776 prefetch_abort_handler(trapframe_t *tf) 777 { 778 struct lwp *l; 779 struct pcb *pcb; 780 struct vm_map *map; 781 vaddr_t fault_pc, va; 782 ksiginfo_t ksi; 783 int error, user; 784 785 UVMHIST_FUNC("prefetch_abort_handler"); UVMHIST_CALLED(maphist); 786 787 /* Update vmmeter statistics */ 788 uvmexp.traps++; 789 790 l = curlwp; 791 pcb = lwp_getpcb(l); 792 793 if ((user = TRAP_USERMODE(tf)) != 0) 794 LWP_CACHE_CREDS(l, l->l_proc); 795 796 /* 797 * Enable IRQ's (disabled by the abort) This always comes 798 * from user mode so we know interrupts were not disabled. 799 * But we check anyway. 800 */ 801 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 802 if (__predict_true((tf->tf_spsr & I32_bit) != IF32_bits)) 803 restore_interrupts(tf->tf_spsr & IF32_bits); 804 805 /* See if the CPU state needs to be fixed up */ 806 switch (prefetch_abort_fixup(tf)) { 807 case ABORT_FIXUP_RETURN: 808 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 809 return; 810 case ABORT_FIXUP_FAILED: 811 /* Deliver a SIGILL to the process */ 812 KSI_INIT_TRAP(&ksi); 813 ksi.ksi_signo = SIGILL; 814 ksi.ksi_code = ILL_ILLOPC; 815 ksi.ksi_addr = (u_int32_t *)(intptr_t) tf->tf_pc; 816 pcb->pcb_tf = tf; 817 goto do_trapsignal; 818 default: 819 break; 820 } 821 822 /* Prefetch aborts cannot happen in kernel mode */ 823 if (__predict_false(!user)) 824 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 825 826 /* Get fault address */ 827 fault_pc = tf->tf_pc; 828 pcb->pcb_tf = tf; 829 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, tf=0x%x)", fault_pc, l, tf, 830 0); 831 832 /* Ok validate the address, can only execute in USER space */ 833 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 834 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 835 KSI_INIT_TRAP(&ksi); 836 ksi.ksi_signo = SIGSEGV; 837 ksi.ksi_code = SEGV_ACCERR; 838 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 839 ksi.ksi_trap = fault_pc; 840 goto do_trapsignal; 841 } 842 843 map = &l->l_proc->p_vmspace->vm_map; 844 va = trunc_page(fault_pc); 845 846 /* 847 * See if the pmap can handle this fault on its own... 848 */ 849 #ifdef DEBUG 850 last_fault_code = -1; 851 #endif 852 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1)) { 853 UVMHIST_LOG (maphist, " <- emulated", 0, 0, 0, 0); 854 goto out; 855 } 856 857 #ifdef DIAGNOSTIC 858 if (__predict_false(l->l_cpu->ci_intr_depth > 0)) { 859 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 860 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 861 } 862 #endif 863 864 #ifdef KERN_SA 865 if (map != kernel_map && (l->l_flag & LW_SA)) { 866 l->l_savp->savp_faultaddr = fault_pc; 867 l->l_pflag |= LP_SA_PAGEFAULT; 868 } 869 #endif 870 871 error = uvm_fault(map, va, VM_PROT_READ); 872 873 #ifdef KERN_SA 874 if (map != kernel_map) 875 l->l_pflag &= ~LP_SA_PAGEFAULT; 876 #endif 877 878 if (__predict_true(error == 0)) { 879 UVMHIST_LOG (maphist, " <- uvm", 0, 0, 0, 0); 880 goto out; 881 } 882 KSI_INIT_TRAP(&ksi); 883 884 UVMHIST_LOG (maphist, " <- fatal (%d)", error, 0, 0, 0); 885 if (error == ENOMEM) { 886 printf("UVM: pid %d (%s), uid %d killed: " 887 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 888 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 889 ksi.ksi_signo = SIGKILL; 890 } else 891 ksi.ksi_signo = SIGSEGV; 892 893 ksi.ksi_code = SEGV_MAPERR; 894 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 895 ksi.ksi_trap = fault_pc; 896 897 do_trapsignal: 898 call_trapsignal(l, &ksi); 899 900 out: 901 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 902 userret(l); 903 } 904 905 /* 906 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 907 * If the read succeeds, the value is written to 'rptr' and zero is returned. 908 * Else, return EFAULT. 909 */ 910 int 911 badaddr_read(void *addr, size_t size, void *rptr) 912 { 913 extern int badaddr_read_1(const uint8_t *, uint8_t *); 914 extern int badaddr_read_2(const uint16_t *, uint16_t *); 915 extern int badaddr_read_4(const uint32_t *, uint32_t *); 916 union { 917 uint8_t v1; 918 uint16_t v2; 919 uint32_t v4; 920 } u; 921 struct pcb *curpcb_save; 922 int rv, s; 923 924 cpu_drain_writebuf(); 925 926 /* 927 * We might be called at interrupt time, so arrange to steal 928 * lwp0's PCB temporarily, if required, so that pcb_onfault 929 * handling works correctly. 930 */ 931 s = splhigh(); 932 if ((curpcb_save = curpcb) == NULL) 933 curpcb = lwp_getpcb(&lwp0); 934 935 /* Read from the test address. */ 936 switch (size) { 937 case sizeof(uint8_t): 938 rv = badaddr_read_1(addr, &u.v1); 939 if (rv == 0 && rptr) 940 *(uint8_t *) rptr = u.v1; 941 break; 942 943 case sizeof(uint16_t): 944 rv = badaddr_read_2(addr, &u.v2); 945 if (rv == 0 && rptr) 946 *(uint16_t *) rptr = u.v2; 947 break; 948 949 case sizeof(uint32_t): 950 rv = badaddr_read_4(addr, &u.v4); 951 if (rv == 0 && rptr) 952 *(uint32_t *) rptr = u.v4; 953 break; 954 955 default: 956 curpcb = curpcb_save; 957 panic("badaddr: invalid size (%lu)", (u_long) size); 958 } 959 960 /* Restore curpcb */ 961 curpcb = curpcb_save; 962 splx(s); 963 964 /* Return EFAULT if the address was invalid, else zero */ 965 return (rv); 966 } 967