1 /* $NetBSD: fault.c,v 1.80 2012/02/19 21:06:04 rmind 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 83 #include <sys/types.h> 84 __KERNEL_RCSID(0, "$NetBSD: fault.c,v 1.80 2012/02/19 21:06:04 rmind Exp $"); 85 86 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/proc.h> 89 #include <sys/kernel.h> 90 #include <sys/kauth.h> 91 #include <sys/cpu.h> 92 93 #include <uvm/uvm_extern.h> 94 #include <uvm/uvm_stat.h> 95 #ifdef UVMHIST 96 #include <uvm/uvm.h> 97 #endif 98 99 #include <arm/cpuconf.h> 100 101 #include <machine/frame.h> 102 #include <arm/arm32/katelib.h> 103 #include <machine/intr.h> 104 #if defined(DDB) || defined(KGDB) 105 #include <machine/db_machdep.h> 106 #ifdef KGDB 107 #include <sys/kgdb.h> 108 #endif 109 #if !defined(DDB) 110 #define kdb_trap kgdb_trap 111 #endif 112 #endif 113 114 #include <arch/arm/arm/disassem.h> 115 #include <arm/arm32/machdep.h> 116 117 extern char fusubailout[]; 118 119 #ifdef DEBUG 120 int last_fault_code; /* For the benefit of pmap_fault_fixup() */ 121 #endif 122 123 #if defined(CPU_ARM3) || defined(CPU_ARM6) || \ 124 defined(CPU_ARM7) || defined(CPU_ARM7TDMI) 125 /* These CPUs may need data/prefetch abort fixups */ 126 #define CPU_ABORT_FIXUP_REQUIRED 127 #endif 128 129 struct data_abort { 130 int (*func)(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 131 const char *desc; 132 }; 133 134 static int dab_fatal(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 135 static int dab_align(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 136 static int dab_buserr(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 137 138 static const struct data_abort data_aborts[] = { 139 {dab_fatal, "Vector Exception"}, 140 {dab_align, "Alignment Fault 1"}, 141 {dab_fatal, "Terminal Exception"}, 142 {dab_align, "Alignment Fault 3"}, 143 {dab_buserr, "External Linefetch Abort (S)"}, 144 {NULL, "Translation Fault (S)"}, 145 {dab_buserr, "External Linefetch Abort (P)"}, 146 {NULL, "Translation Fault (P)"}, 147 {dab_buserr, "External Non-Linefetch Abort (S)"}, 148 {NULL, "Domain Fault (S)"}, 149 {dab_buserr, "External Non-Linefetch Abort (P)"}, 150 {NULL, "Domain Fault (P)"}, 151 {dab_buserr, "External Translation Abort (L1)"}, 152 {NULL, "Permission Fault (S)"}, 153 {dab_buserr, "External Translation Abort (L2)"}, 154 {NULL, "Permission Fault (P)"} 155 }; 156 157 /* Determine if a fault came from user mode */ 158 #define TRAP_USERMODE(tf) ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE) 159 160 /* Determine if 'x' is a permission fault */ 161 #define IS_PERMISSION_FAULT(x) \ 162 (((1 << ((x) & FAULT_TYPE_MASK)) & \ 163 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) 164 165 #if 0 166 /* maybe one day we'll do emulations */ 167 #define TRAPSIGNAL(l,k) (*(l)->l_proc->p_emul->e_trapsignal)((l), (k)) 168 #else 169 #define TRAPSIGNAL(l,k) trapsignal((l), (k)) 170 #endif 171 172 static inline void 173 call_trapsignal(struct lwp *l, ksiginfo_t *ksi) 174 { 175 176 TRAPSIGNAL(l, ksi); 177 } 178 179 static inline int 180 data_abort_fixup(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l) 181 { 182 #ifdef CPU_ABORT_FIXUP_REQUIRED 183 int error; 184 185 /* Call the CPU specific data abort fixup routine */ 186 error = cpu_dataabt_fixup(tf); 187 if (__predict_true(error != ABORT_FIXUP_FAILED)) 188 return (error); 189 190 /* 191 * Oops, couldn't fix up the instruction 192 */ 193 printf("%s: fixup for %s mode data abort failed.\n", __func__, 194 TRAP_USERMODE(tf) ? "user" : "kernel"); 195 #ifdef THUMB_CODE 196 if (tf->tf_spsr & PSR_T_bit) { 197 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 198 tf->tf_pc, *((u_int16 *)(tf->tf_pc & ~1)), 199 *((u_int16 *)((tf->tf_pc + 2) & ~1))); 200 } 201 else 202 #endif 203 { 204 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 205 *((u_int *)tf->tf_pc)); 206 } 207 disassemble(tf->tf_pc); 208 209 /* Die now if this happened in kernel mode */ 210 if (!TRAP_USERMODE(tf)) 211 dab_fatal(tf, fsr, far, l, NULL); 212 213 return (error); 214 #else 215 return (ABORT_FIXUP_OK); 216 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 217 } 218 219 void 220 data_abort_handler(trapframe_t *tf) 221 { 222 struct vm_map *map; 223 struct pcb *pcb; 224 struct lwp *l; 225 u_int user, far, fsr; 226 vm_prot_t ftype; 227 void *onfault; 228 vaddr_t va; 229 int error; 230 ksiginfo_t ksi; 231 232 UVMHIST_FUNC("data_abort_handler"); 233 234 /* Grab FAR/FSR before enabling interrupts */ 235 far = cpu_faultaddress(); 236 fsr = cpu_faultstatus(); 237 238 UVMHIST_CALLED(maphist); 239 /* Update vmmeter statistics */ 240 curcpu()->ci_data.cpu_ntrap++; 241 242 /* Re-enable interrupts if they were enabled previously */ 243 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 244 if (__predict_true((tf->tf_spsr & IF32_bits) != IF32_bits)) 245 restore_interrupts(tf->tf_spsr & IF32_bits); 246 247 /* Get the current lwp structure */ 248 KASSERT(curlwp != NULL); 249 l = curlwp; 250 251 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, far=0x%x, fsr=0x%x)", 252 tf->tf_pc, l, far, fsr); 253 254 /* Data abort came from user mode? */ 255 if ((user = TRAP_USERMODE(tf)) != 0) 256 LWP_CACHE_CREDS(l, l->l_proc); 257 258 /* Grab the current pcb */ 259 pcb = lwp_getpcb(l); 260 261 /* Invoke the appropriate handler, if necessary */ 262 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 263 #ifdef DIAGNOSTIC 264 printf("%s: data_aborts fsr=0x%x far=0x%x\n", 265 __func__, fsr, far); 266 #endif 267 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, 268 l, &ksi)) 269 goto do_trapsignal; 270 goto out; 271 } 272 273 /* 274 * At this point, we're dealing with one of the following data aborts: 275 * 276 * FAULT_TRANS_S - Translation -- Section 277 * FAULT_TRANS_P - Translation -- Page 278 * FAULT_DOMAIN_S - Domain -- Section 279 * FAULT_DOMAIN_P - Domain -- Page 280 * FAULT_PERM_S - Permission -- Section 281 * FAULT_PERM_P - Permission -- Page 282 * 283 * These are the main virtual memory-related faults signalled by 284 * the MMU. 285 */ 286 287 /* fusubailout is used by [fs]uswintr to avoid page faulting */ 288 if (__predict_false(pcb->pcb_onfault == fusubailout)) { 289 tf->tf_r0 = EFAULT; 290 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 291 return; 292 } 293 294 if (user) { 295 pcb->pcb_tf = tf; 296 } 297 298 /* 299 * Make sure the Program Counter is sane. We could fall foul of 300 * someone executing Thumb code, in which case the PC might not 301 * be word-aligned. This would cause a kernel alignment fault 302 * further down if we have to decode the current instruction. 303 */ 304 #ifdef THUMB_CODE 305 /* 306 * XXX: It would be nice to be able to support Thumb in the kernel 307 * at some point. 308 */ 309 if (__predict_false(!user && (tf->tf_pc & 3) != 0)) { 310 printf("\n%s: Misaligned Kernel-mode Program Counter\n", 311 __func__); 312 dab_fatal(tf, fsr, far, l, NULL); 313 } 314 #else 315 if (__predict_false((tf->tf_pc & 3) != 0)) { 316 if (user) { 317 /* 318 * Give the user an illegal instruction signal. 319 */ 320 /* Deliver a SIGILL to the process */ 321 KSI_INIT_TRAP(&ksi); 322 ksi.ksi_signo = SIGILL; 323 ksi.ksi_code = ILL_ILLOPC; 324 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 325 ksi.ksi_trap = fsr; 326 goto do_trapsignal; 327 } 328 329 /* 330 * The kernel never executes Thumb code. 331 */ 332 printf("\n%s: Misaligned Kernel-mode Program Counter\n", 333 __func__); 334 dab_fatal(tf, fsr, far, l, NULL); 335 } 336 #endif 337 338 /* See if the CPU state needs to be fixed up */ 339 switch (data_abort_fixup(tf, fsr, far, l)) { 340 case ABORT_FIXUP_RETURN: 341 return; 342 case ABORT_FIXUP_FAILED: 343 /* Deliver a SIGILL to the process */ 344 KSI_INIT_TRAP(&ksi); 345 ksi.ksi_signo = SIGILL; 346 ksi.ksi_code = ILL_ILLOPC; 347 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 348 ksi.ksi_trap = fsr; 349 goto do_trapsignal; 350 default: 351 break; 352 } 353 354 va = trunc_page((vaddr_t)far); 355 356 /* 357 * It is only a kernel address space fault iff: 358 * 1. user == 0 and 359 * 2. pcb_onfault not set or 360 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. 361 */ 362 if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS || 363 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && 364 __predict_true((pcb->pcb_onfault == NULL || 365 (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) { 366 map = kernel_map; 367 368 /* Was the fault due to the FPE/IPKDB ? */ 369 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { 370 KSI_INIT_TRAP(&ksi); 371 ksi.ksi_signo = SIGSEGV; 372 ksi.ksi_code = SEGV_ACCERR; 373 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 374 ksi.ksi_trap = fsr; 375 376 /* 377 * Force exit via userret() 378 * This is necessary as the FPE is an extension to 379 * userland that actually runs in a priveledged mode 380 * but uses USR mode permissions for its accesses. 381 */ 382 user = 1; 383 goto do_trapsignal; 384 } 385 } else { 386 map = &l->l_proc->p_vmspace->vm_map; 387 } 388 389 /* 390 * We need to know whether the page should be mapped 391 * as R or R/W. The MMU does not give us the info as 392 * to whether the fault was caused by a read or a write. 393 * 394 * However, we know that a permission fault can only be 395 * the result of a write to a read-only location, so 396 * we can deal with those quickly. 397 * 398 * Otherwise we need to disassemble the instruction 399 * responsible to determine if it was a write. 400 */ 401 if (IS_PERMISSION_FAULT(fsr)) 402 ftype = VM_PROT_WRITE; 403 else { 404 #ifdef THUMB_CODE 405 /* Fast track the ARM case. */ 406 if (__predict_false(tf->tf_spsr & PSR_T_bit)) { 407 u_int insn = fusword((void *)(tf->tf_pc & ~1)); 408 u_int insn_f8 = insn & 0xf800; 409 u_int insn_fe = insn & 0xfe00; 410 411 if (insn_f8 == 0x6000 || /* STR(1) */ 412 insn_f8 == 0x7000 || /* STRB(1) */ 413 insn_f8 == 0x8000 || /* STRH(1) */ 414 insn_f8 == 0x9000 || /* STR(3) */ 415 insn_f8 == 0xc000 || /* STM */ 416 insn_fe == 0x5000 || /* STR(2) */ 417 insn_fe == 0x5200 || /* STRH(2) */ 418 insn_fe == 0x5400) /* STRB(2) */ 419 ftype = VM_PROT_WRITE; 420 else 421 ftype = VM_PROT_READ; 422 } 423 else 424 #endif 425 { 426 u_int insn = ReadWord(tf->tf_pc); 427 428 if (((insn & 0x0c100000) == 0x04000000) || /* STR[B] */ 429 ((insn & 0x0e1000b0) == 0x000000b0) || /* STR[HD]*/ 430 ((insn & 0x0a100000) == 0x08000000)) /* STM/CDT*/ 431 ftype = VM_PROT_WRITE; 432 else if ((insn & 0x0fb00ff0) == 0x01000090)/* SWP */ 433 ftype = VM_PROT_READ | VM_PROT_WRITE; 434 else 435 ftype = VM_PROT_READ; 436 } 437 } 438 439 /* 440 * See if the fault is as a result of ref/mod emulation, 441 * or domain mismatch. 442 */ 443 #ifdef DEBUG 444 last_fault_code = fsr; 445 #endif 446 if (pmap_fault_fixup(map->pmap, va, ftype, user)) { 447 UVMHIST_LOG(maphist, " <- ref/mod emul", 0, 0, 0, 0); 448 goto out; 449 } 450 451 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 452 if (pcb->pcb_onfault) { 453 tf->tf_r0 = EINVAL; 454 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 455 return; 456 } 457 printf("\nNon-emulated page fault with intr_depth > 0\n"); 458 dab_fatal(tf, fsr, far, l, NULL); 459 } 460 461 onfault = pcb->pcb_onfault; 462 pcb->pcb_onfault = NULL; 463 error = uvm_fault(map, va, ftype); 464 pcb->pcb_onfault = onfault; 465 466 if (__predict_true(error == 0)) { 467 if (user) 468 uvm_grow(l->l_proc, va); /* Record any stack growth */ 469 else 470 ucas_ras_check(tf); 471 UVMHIST_LOG(maphist, " <- uvm", 0, 0, 0, 0); 472 goto out; 473 } 474 475 if (user == 0) { 476 if (pcb->pcb_onfault) { 477 tf->tf_r0 = error; 478 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 479 return; 480 } 481 482 printf("\nuvm_fault(%p, %lx, %x) -> %x\n", map, va, ftype, 483 error); 484 dab_fatal(tf, fsr, far, l, NULL); 485 } 486 487 KSI_INIT_TRAP(&ksi); 488 489 if (error == ENOMEM) { 490 printf("UVM: pid %d (%s), uid %d killed: " 491 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 492 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 493 ksi.ksi_signo = SIGKILL; 494 } else 495 ksi.ksi_signo = SIGSEGV; 496 497 ksi.ksi_code = (error == EACCES) ? SEGV_ACCERR : SEGV_MAPERR; 498 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 499 ksi.ksi_trap = fsr; 500 UVMHIST_LOG(maphist, " <- error (%d)", error, 0, 0, 0); 501 502 do_trapsignal: 503 call_trapsignal(l, &ksi); 504 out: 505 /* If returning to user mode, make sure to invoke userret() */ 506 if (user) 507 userret(l); 508 } 509 510 /* 511 * dab_fatal() handles the following data aborts: 512 * 513 * FAULT_WRTBUF_0 - Vector Exception 514 * FAULT_WRTBUF_1 - Terminal Exception 515 * 516 * We should never see these on a properly functioning system. 517 * 518 * This function is also called by the other handlers if they 519 * detect a fatal problem. 520 * 521 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 522 */ 523 static int 524 dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 525 { 526 const char *mode; 527 528 mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 529 530 if (l != NULL) { 531 printf("Fatal %s mode data abort: '%s'\n", mode, 532 data_aborts[fsr & FAULT_TYPE_MASK].desc); 533 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 534 if ((fsr & FAULT_IMPRECISE) == 0) 535 printf("%08x, ", far); 536 else 537 printf("Invalid, "); 538 printf("spsr=%08x\n", tf->tf_spsr); 539 } else { 540 printf("Fatal %s mode prefetch abort at 0x%08x\n", 541 mode, tf->tf_pc); 542 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 543 } 544 545 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 546 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 547 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 548 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 549 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 550 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 551 printf("r12=%08x, ", tf->tf_r12); 552 553 if (TRAP_USERMODE(tf)) 554 printf("usp=%08x, ulr=%08x", 555 tf->tf_usr_sp, tf->tf_usr_lr); 556 else 557 printf("ssp=%08x, slr=%08x", 558 tf->tf_svc_sp, tf->tf_svc_lr); 559 printf(", pc =%08x\n\n", tf->tf_pc); 560 561 #if defined(DDB) || defined(KGDB) 562 kdb_trap(T_FAULT, tf); 563 #endif 564 panic("Fatal abort"); 565 /*NOTREACHED*/ 566 } 567 568 /* 569 * dab_align() handles the following data aborts: 570 * 571 * FAULT_ALIGN_0 - Alignment fault 572 * FAULT_ALIGN_0 - Alignment fault 573 * 574 * These faults are fatal if they happen in kernel mode. Otherwise, we 575 * deliver a bus error to the process. 576 */ 577 static int 578 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 579 { 580 struct pcb *pcb = lwp_getpcb(l); 581 582 /* Alignment faults are always fatal if they occur in kernel mode */ 583 if (!TRAP_USERMODE(tf)) 584 dab_fatal(tf, fsr, far, l, NULL); 585 586 /* pcb_onfault *must* be NULL at this point */ 587 KDASSERT(pcb->pcb_onfault == NULL); 588 589 /* See if the CPU state needs to be fixed up */ 590 (void) data_abort_fixup(tf, fsr, far, l); 591 592 /* Deliver a bus error signal to the process */ 593 KSI_INIT_TRAP(ksi); 594 ksi->ksi_signo = SIGBUS; 595 ksi->ksi_code = BUS_ADRALN; 596 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 597 ksi->ksi_trap = fsr; 598 599 pcb->pcb_tf = tf; 600 601 return (1); 602 } 603 604 /* 605 * dab_buserr() handles the following data aborts: 606 * 607 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 608 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 609 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 610 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 611 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 612 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 613 * 614 * If pcb_onfault is set, flag the fault and return to the handler. 615 * If the fault occurred in user mode, give the process a SIGBUS. 616 * 617 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 618 * can be flagged as imprecise in the FSR. This causes a real headache 619 * since some of the machine state is lost. In this case, tf->tf_pc 620 * may not actually point to the offending instruction. In fact, if 621 * we've taken a double abort fault, it generally points somewhere near 622 * the top of "data_abort_entry" in exception.S. 623 * 624 * In all other cases, these data aborts are considered fatal. 625 */ 626 static int 627 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 628 ksiginfo_t *ksi) 629 { 630 struct pcb *pcb = lwp_getpcb(l); 631 632 #ifdef __XSCALE__ 633 if ((fsr & FAULT_IMPRECISE) != 0 && 634 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 635 /* 636 * Oops, an imprecise, double abort fault. We've lost the 637 * r14_abt/spsr_abt values corresponding to the original 638 * abort, and the spsr saved in the trapframe indicates 639 * ABT mode. 640 */ 641 tf->tf_spsr &= ~PSR_MODE; 642 643 /* 644 * We use a simple heuristic to determine if the double abort 645 * happened as a result of a kernel or user mode access. 646 * If the current trapframe is at the top of the kernel stack, 647 * the fault _must_ have come from user mode. 648 */ 649 if (tf != ((trapframe_t *)pcb->pcb_un.un_32.pcb32_sp) - 1) { 650 /* 651 * Kernel mode. We're either about to die a 652 * spectacular death, or pcb_onfault will come 653 * to our rescue. Either way, the current value 654 * of tf->tf_pc is irrelevant. 655 */ 656 tf->tf_spsr |= PSR_SVC32_MODE; 657 if (pcb->pcb_onfault == NULL) 658 printf("\nKernel mode double abort!\n"); 659 } else { 660 /* 661 * User mode. We've lost the program counter at the 662 * time of the fault (not that it was accurate anyway; 663 * it's not called an imprecise fault for nothing). 664 * About all we can do is copy r14_usr to tf_pc and 665 * hope for the best. The process is about to get a 666 * SIGBUS, so it's probably history anyway. 667 */ 668 tf->tf_spsr |= PSR_USR32_MODE; 669 tf->tf_pc = tf->tf_usr_lr; 670 #ifdef THUMB_CODE 671 tf->tf_spsr &= ~PSR_T_bit; 672 if (tf->tf_usr_lr & 1) 673 tf->tf_spsr |= PSR_T_bit; 674 #endif 675 } 676 } 677 678 /* FAR is invalid for imprecise exceptions */ 679 if ((fsr & FAULT_IMPRECISE) != 0) 680 far = 0; 681 #endif /* __XSCALE__ */ 682 683 if (pcb->pcb_onfault) { 684 KDASSERT(TRAP_USERMODE(tf) == 0); 685 tf->tf_r0 = EFAULT; 686 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 687 return (0); 688 } 689 690 /* See if the CPU state needs to be fixed up */ 691 (void) data_abort_fixup(tf, fsr, far, l); 692 693 /* 694 * At this point, if the fault happened in kernel mode, we're toast 695 */ 696 if (!TRAP_USERMODE(tf)) 697 dab_fatal(tf, fsr, far, l, NULL); 698 699 /* Deliver a bus error signal to the process */ 700 KSI_INIT_TRAP(ksi); 701 ksi->ksi_signo = SIGBUS; 702 ksi->ksi_code = BUS_ADRERR; 703 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 704 ksi->ksi_trap = fsr; 705 706 pcb->pcb_tf = tf; 707 708 return (1); 709 } 710 711 static inline int 712 prefetch_abort_fixup(trapframe_t *tf) 713 { 714 #ifdef CPU_ABORT_FIXUP_REQUIRED 715 int error; 716 717 /* Call the CPU specific prefetch abort fixup routine */ 718 error = cpu_prefetchabt_fixup(tf); 719 if (__predict_true(error != ABORT_FIXUP_FAILED)) 720 return (error); 721 722 /* 723 * Oops, couldn't fix up the instruction 724 */ 725 printf("%s: fixup for %s mode prefetch abort failed.\n", __func__, 726 TRAP_USERMODE(tf) ? "user" : "kernel"); 727 #ifdef THUMB_CODE 728 if (tf->tf_spsr & PSR_T_bit) { 729 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 730 tf->tf_pc, *((u_int16 *)(tf->tf_pc & ~1)), 731 *((u_int16 *)((tf->tf_pc + 2) & ~1))); 732 } 733 else 734 #endif 735 { 736 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 737 *((u_int *)tf->tf_pc)); 738 } 739 disassemble(tf->tf_pc); 740 741 /* Die now if this happened in kernel mode */ 742 if (!TRAP_USERMODE(tf)) 743 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 744 745 return (error); 746 #else 747 return (ABORT_FIXUP_OK); 748 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 749 } 750 751 /* 752 * void prefetch_abort_handler(trapframe_t *tf) 753 * 754 * Abort handler called when instruction execution occurs at 755 * a non existent or restricted (access permissions) memory page. 756 * If the address is invalid and we were in SVC mode then panic as 757 * the kernel should never prefetch abort. 758 * If the address is invalid and the page is mapped then the user process 759 * does no have read permission so send it a signal. 760 * Otherwise fault the page in and try again. 761 */ 762 void 763 prefetch_abort_handler(trapframe_t *tf) 764 { 765 struct lwp *l; 766 struct pcb *pcb; 767 struct vm_map *map; 768 vaddr_t fault_pc, va; 769 ksiginfo_t ksi; 770 int error, user; 771 772 UVMHIST_FUNC("prefetch_abort_handler"); UVMHIST_CALLED(maphist); 773 774 /* Update vmmeter statistics */ 775 curcpu()->ci_data.cpu_ntrap++; 776 777 l = curlwp; 778 pcb = lwp_getpcb(l); 779 780 if ((user = TRAP_USERMODE(tf)) != 0) 781 LWP_CACHE_CREDS(l, l->l_proc); 782 783 /* 784 * Enable IRQ's (disabled by the abort) This always comes 785 * from user mode so we know interrupts were not disabled. 786 * But we check anyway. 787 */ 788 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 789 if (__predict_true((tf->tf_spsr & I32_bit) != IF32_bits)) 790 restore_interrupts(tf->tf_spsr & IF32_bits); 791 792 /* See if the CPU state needs to be fixed up */ 793 switch (prefetch_abort_fixup(tf)) { 794 case ABORT_FIXUP_RETURN: 795 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 796 return; 797 case ABORT_FIXUP_FAILED: 798 /* Deliver a SIGILL to the process */ 799 KSI_INIT_TRAP(&ksi); 800 ksi.ksi_signo = SIGILL; 801 ksi.ksi_code = ILL_ILLOPC; 802 ksi.ksi_addr = (u_int32_t *)(intptr_t) tf->tf_pc; 803 pcb->pcb_tf = tf; 804 goto do_trapsignal; 805 default: 806 break; 807 } 808 809 /* Prefetch aborts cannot happen in kernel mode */ 810 if (__predict_false(!user)) 811 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 812 813 /* Get fault address */ 814 fault_pc = tf->tf_pc; 815 pcb->pcb_tf = tf; 816 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, tf=0x%x)", fault_pc, l, tf, 817 0); 818 819 /* Ok validate the address, can only execute in USER space */ 820 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 821 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 822 KSI_INIT_TRAP(&ksi); 823 ksi.ksi_signo = SIGSEGV; 824 ksi.ksi_code = SEGV_ACCERR; 825 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 826 ksi.ksi_trap = fault_pc; 827 goto do_trapsignal; 828 } 829 830 map = &l->l_proc->p_vmspace->vm_map; 831 va = trunc_page(fault_pc); 832 833 /* 834 * See if the pmap can handle this fault on its own... 835 */ 836 #ifdef DEBUG 837 last_fault_code = -1; 838 #endif 839 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1)) { 840 UVMHIST_LOG (maphist, " <- emulated", 0, 0, 0, 0); 841 goto out; 842 } 843 844 #ifdef DIAGNOSTIC 845 if (__predict_false(l->l_cpu->ci_intr_depth > 0)) { 846 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 847 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 848 } 849 #endif 850 851 KASSERT(pcb->pcb_onfault == NULL); 852 error = uvm_fault(map, va, VM_PROT_READ); 853 854 if (__predict_true(error == 0)) { 855 UVMHIST_LOG (maphist, " <- uvm", 0, 0, 0, 0); 856 goto out; 857 } 858 KSI_INIT_TRAP(&ksi); 859 860 UVMHIST_LOG (maphist, " <- fatal (%d)", error, 0, 0, 0); 861 if (error == ENOMEM) { 862 printf("UVM: pid %d (%s), uid %d killed: " 863 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 864 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 865 ksi.ksi_signo = SIGKILL; 866 } else 867 ksi.ksi_signo = SIGSEGV; 868 869 ksi.ksi_code = SEGV_MAPERR; 870 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 871 ksi.ksi_trap = fault_pc; 872 873 do_trapsignal: 874 call_trapsignal(l, &ksi); 875 876 out: 877 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 878 userret(l); 879 } 880 881 /* 882 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 883 * If the read succeeds, the value is written to 'rptr' and zero is returned. 884 * Else, return EFAULT. 885 */ 886 int 887 badaddr_read(void *addr, size_t size, void *rptr) 888 { 889 extern int badaddr_read_1(const uint8_t *, uint8_t *); 890 extern int badaddr_read_2(const uint16_t *, uint16_t *); 891 extern int badaddr_read_4(const uint32_t *, uint32_t *); 892 union { 893 uint8_t v1; 894 uint16_t v2; 895 uint32_t v4; 896 } u; 897 struct pcb *curpcb_save; 898 int rv, s; 899 900 cpu_drain_writebuf(); 901 902 /* 903 * We might be called at interrupt time, so arrange to steal 904 * lwp0's PCB temporarily, if required, so that pcb_onfault 905 * handling works correctly. 906 */ 907 s = splhigh(); 908 if ((curpcb_save = curpcb) == NULL) 909 curpcb = lwp_getpcb(&lwp0); 910 911 /* Read from the test address. */ 912 switch (size) { 913 case sizeof(uint8_t): 914 rv = badaddr_read_1(addr, &u.v1); 915 if (rv == 0 && rptr) 916 *(uint8_t *) rptr = u.v1; 917 break; 918 919 case sizeof(uint16_t): 920 rv = badaddr_read_2(addr, &u.v2); 921 if (rv == 0 && rptr) 922 *(uint16_t *) rptr = u.v2; 923 break; 924 925 case sizeof(uint32_t): 926 rv = badaddr_read_4(addr, &u.v4); 927 if (rv == 0 && rptr) 928 *(uint32_t *) rptr = u.v4; 929 break; 930 931 default: 932 curpcb = curpcb_save; 933 panic("%s: invalid size (%lu)", __func__, (u_long)size); 934 } 935 936 /* Restore curpcb */ 937 curpcb = curpcb_save; 938 splx(s); 939 940 /* Return EFAULT if the address was invalid, else zero */ 941 return (rv); 942 } 943