1 /* $NetBSD: fault.c,v 1.68 2008/05/21 14:10:28 ad 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 1.68 2008/05/21 14:10:28 ad Exp $"); 85 86 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/proc.h> 89 #include <sys/user.h> 90 #include <sys/kernel.h> 91 #include <sys/kauth.h> 92 #include <sys/cpu.h> 93 94 #include <uvm/uvm_extern.h> 95 #include <uvm/uvm_stat.h> 96 #ifdef UVMHIST 97 #include <uvm/uvm.h> 98 #endif 99 100 #include <arm/cpuconf.h> 101 102 #include <machine/frame.h> 103 #include <arm/arm32/katelib.h> 104 #include <machine/intr.h> 105 #if defined(DDB) || defined(KGDB) 106 #include <machine/db_machdep.h> 107 #ifdef KGDB 108 #include <sys/kgdb.h> 109 #endif 110 #if !defined(DDB) 111 #define kdb_trap kgdb_trap 112 #endif 113 #endif 114 115 #include <arch/arm/arm/disassem.h> 116 #include <arm/arm32/machdep.h> 117 118 extern char fusubailout[]; 119 120 #ifdef DEBUG 121 int last_fault_code; /* For the benefit of pmap_fault_fixup() */ 122 #endif 123 124 #if defined(CPU_ARM3) || defined(CPU_ARM6) || \ 125 defined(CPU_ARM7) || defined(CPU_ARM7TDMI) 126 /* These CPUs may need data/prefetch abort fixups */ 127 #define CPU_ABORT_FIXUP_REQUIRED 128 #endif 129 130 struct data_abort { 131 int (*func)(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 132 const char *desc; 133 }; 134 135 static int dab_fatal(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 136 static int dab_align(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 137 static int dab_buserr(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 138 139 static const struct data_abort data_aborts[] = { 140 {dab_fatal, "Vector Exception"}, 141 {dab_align, "Alignment Fault 1"}, 142 {dab_fatal, "Terminal Exception"}, 143 {dab_align, "Alignment Fault 3"}, 144 {dab_buserr, "External Linefetch Abort (S)"}, 145 {NULL, "Translation Fault (S)"}, 146 {dab_buserr, "External Linefetch Abort (P)"}, 147 {NULL, "Translation Fault (P)"}, 148 {dab_buserr, "External Non-Linefetch Abort (S)"}, 149 {NULL, "Domain Fault (S)"}, 150 {dab_buserr, "External Non-Linefetch Abort (P)"}, 151 {NULL, "Domain Fault (P)"}, 152 {dab_buserr, "External Translation Abort (L1)"}, 153 {NULL, "Permission Fault (S)"}, 154 {dab_buserr, "External Translation Abort (L2)"}, 155 {NULL, "Permission Fault (P)"} 156 }; 157 158 /* Determine if a fault came from user mode */ 159 #define TRAP_USERMODE(tf) ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE) 160 161 /* Determine if 'x' is a permission fault */ 162 #define IS_PERMISSION_FAULT(x) \ 163 (((1 << ((x) & FAULT_TYPE_MASK)) & \ 164 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) 165 166 #if 0 167 /* maybe one day we'll do emulations */ 168 #define TRAPSIGNAL(l,k) (*(l)->l_proc->p_emul->e_trapsignal)((l), (k)) 169 #else 170 #define TRAPSIGNAL(l,k) trapsignal((l), (k)) 171 #endif 172 173 static inline void 174 call_trapsignal(struct lwp *l, ksiginfo_t *ksi) 175 { 176 177 TRAPSIGNAL(l, ksi); 178 } 179 180 static inline int 181 data_abort_fixup(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l) 182 { 183 #ifdef CPU_ABORT_FIXUP_REQUIRED 184 int error; 185 186 /* Call the CPU specific data abort fixup routine */ 187 error = cpu_dataabt_fixup(tf); 188 if (__predict_true(error != ABORT_FIXUP_FAILED)) 189 return (error); 190 191 /* 192 * Oops, couldn't fix up the instruction 193 */ 194 printf("data_abort_fixup: fixup for %s mode data abort failed.\n", 195 TRAP_USERMODE(tf) ? "user" : "kernel"); 196 #ifdef THUMB_CODE 197 if (tf->tf_spsr & PSR_T_bit) { 198 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 199 tf->tf_pc, *((u_int16 *)(tf->tf_pc & ~1)), 200 *((u_int16 *)((tf->tf_pc + 2) & ~1))); 201 } 202 else 203 #endif 204 { 205 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 206 *((u_int *)tf->tf_pc)); 207 } 208 disassemble(tf->tf_pc); 209 210 /* Die now if this happened in kernel mode */ 211 if (!TRAP_USERMODE(tf)) 212 dab_fatal(tf, fsr, far, l, NULL); 213 214 return (error); 215 #else 216 return (ABORT_FIXUP_OK); 217 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 218 } 219 220 void 221 data_abort_handler(trapframe_t *tf) 222 { 223 struct vm_map *map; 224 struct pcb *pcb; 225 struct lwp *l; 226 u_int user, far, fsr; 227 vm_prot_t ftype; 228 void *onfault; 229 vaddr_t va; 230 int error; 231 ksiginfo_t ksi; 232 233 UVMHIST_FUNC("data_abort_handler"); 234 235 /* Grab FAR/FSR before enabling interrupts */ 236 far = cpu_faultaddress(); 237 fsr = cpu_faultstatus(); 238 239 UVMHIST_CALLED(maphist); 240 /* Update vmmeter statistics */ 241 uvmexp.traps++; 242 243 /* Re-enable interrupts if they were enabled previously */ 244 if (__predict_true((tf->tf_spsr & I32_bit) == 0)) 245 enable_interrupts(I32_bit); 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 = &l->l_addr->u_pcb; 260 261 /* Invoke the appropriate handler, if necessary */ 262 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 263 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, 264 l, &ksi)) 265 goto do_trapsignal; 266 goto out; 267 } 268 269 /* 270 * At this point, we're dealing with one of the following data aborts: 271 * 272 * FAULT_TRANS_S - Translation -- Section 273 * FAULT_TRANS_P - Translation -- Page 274 * FAULT_DOMAIN_S - Domain -- Section 275 * FAULT_DOMAIN_P - Domain -- Page 276 * FAULT_PERM_S - Permission -- Section 277 * FAULT_PERM_P - Permission -- Page 278 * 279 * These are the main virtual memory-related faults signalled by 280 * the MMU. 281 */ 282 283 /* fusubailout is used by [fs]uswintr to avoid page faulting */ 284 if (__predict_false(pcb->pcb_onfault == fusubailout)) { 285 tf->tf_r0 = EFAULT; 286 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 287 return; 288 } 289 290 if (user) 291 l->l_addr->u_pcb.pcb_tf = tf; 292 293 /* 294 * Make sure the Program Counter is sane. We could fall foul of 295 * someone executing Thumb code, in which case the PC might not 296 * be word-aligned. This would cause a kernel alignment fault 297 * further down if we have to decode the current instruction. 298 */ 299 #ifdef THUMB_CODE 300 /* 301 * XXX: It would be nice to be able to support Thumb in the kernel 302 * at some point. 303 */ 304 if (__predict_false(!user && (tf->tf_pc & 3) != 0)) { 305 printf("\ndata_abort_fault: Misaligned Kernel-mode " 306 "Program Counter\n"); 307 dab_fatal(tf, fsr, far, l, NULL); 308 } 309 #else 310 if (__predict_false((tf->tf_pc & 3) != 0)) { 311 if (user) { 312 /* 313 * Give the user an illegal instruction signal. 314 */ 315 /* Deliver a SIGILL to the process */ 316 KSI_INIT_TRAP(&ksi); 317 ksi.ksi_signo = SIGILL; 318 ksi.ksi_code = ILL_ILLOPC; 319 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 320 ksi.ksi_trap = fsr; 321 goto do_trapsignal; 322 } 323 324 /* 325 * The kernel never executes Thumb code. 326 */ 327 printf("\ndata_abort_fault: Misaligned Kernel-mode " 328 "Program Counter\n"); 329 dab_fatal(tf, fsr, far, l, NULL); 330 } 331 #endif 332 333 /* See if the CPU state needs to be fixed up */ 334 switch (data_abort_fixup(tf, fsr, far, l)) { 335 case ABORT_FIXUP_RETURN: 336 return; 337 case ABORT_FIXUP_FAILED: 338 /* Deliver a SIGILL to the process */ 339 KSI_INIT_TRAP(&ksi); 340 ksi.ksi_signo = SIGILL; 341 ksi.ksi_code = ILL_ILLOPC; 342 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 343 ksi.ksi_trap = fsr; 344 goto do_trapsignal; 345 default: 346 break; 347 } 348 349 va = trunc_page((vaddr_t)far); 350 351 /* 352 * It is only a kernel address space fault iff: 353 * 1. user == 0 and 354 * 2. pcb_onfault not set or 355 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. 356 */ 357 if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS || 358 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && 359 __predict_true((pcb->pcb_onfault == NULL || 360 (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) { 361 map = kernel_map; 362 363 /* Was the fault due to the FPE/IPKDB ? */ 364 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { 365 KSI_INIT_TRAP(&ksi); 366 ksi.ksi_signo = SIGSEGV; 367 ksi.ksi_code = SEGV_ACCERR; 368 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 369 ksi.ksi_trap = fsr; 370 371 /* 372 * Force exit via userret() 373 * This is necessary as the FPE is an extension to 374 * userland that actually runs in a priveledged mode 375 * but uses USR mode permissions for its accesses. 376 */ 377 user = 1; 378 goto do_trapsignal; 379 } 380 } else 381 map = &l->l_proc->p_vmspace->vm_map; 382 383 /* 384 * We need to know whether the page should be mapped 385 * as R or R/W. The MMU does not give us the info as 386 * to whether the fault was caused by a read or a write. 387 * 388 * However, we know that a permission fault can only be 389 * the result of a write to a read-only location, so 390 * we can deal with those quickly. 391 * 392 * Otherwise we need to disassemble the instruction 393 * responsible to determine if it was a write. 394 */ 395 if (IS_PERMISSION_FAULT(fsr)) 396 ftype = VM_PROT_WRITE; 397 else { 398 #ifdef THUMB_CODE 399 /* Fast track the ARM case. */ 400 if (__predict_false(tf->tf_spsr & PSR_T_bit)) { 401 u_int insn = fusword((void *)(tf->tf_pc & ~1)); 402 u_int insn_f8 = insn & 0xf800; 403 u_int insn_fe = insn & 0xfe00; 404 405 if (insn_f8 == 0x6000 || /* STR(1) */ 406 insn_f8 == 0x7000 || /* STRB(1) */ 407 insn_f8 == 0x8000 || /* STRH(1) */ 408 insn_f8 == 0x9000 || /* STR(3) */ 409 insn_f8 == 0xc000 || /* STM */ 410 insn_fe == 0x5000 || /* STR(2) */ 411 insn_fe == 0x5200 || /* STRH(2) */ 412 insn_fe == 0x5400) /* STRB(2) */ 413 ftype = VM_PROT_WRITE; 414 else 415 ftype = VM_PROT_READ; 416 } 417 else 418 #endif 419 { 420 u_int insn = ReadWord(tf->tf_pc); 421 422 if (((insn & 0x0c100000) == 0x04000000) || /* STR[B] */ 423 ((insn & 0x0e1000b0) == 0x000000b0) || /* STR[HD]*/ 424 ((insn & 0x0a100000) == 0x08000000)) /* STM/CDT*/ 425 ftype = VM_PROT_WRITE; 426 else if ((insn & 0x0fb00ff0) == 0x01000090)/* SWP */ 427 ftype = VM_PROT_READ | VM_PROT_WRITE; 428 else 429 ftype = VM_PROT_READ; 430 } 431 } 432 433 /* 434 * See if the fault is as a result of ref/mod emulation, 435 * or domain mismatch. 436 */ 437 #ifdef DEBUG 438 last_fault_code = fsr; 439 #endif 440 if (pmap_fault_fixup(map->pmap, va, ftype, user)) { 441 UVMHIST_LOG(maphist, " <- ref/mod emul", 0, 0, 0, 0); 442 goto out; 443 } 444 445 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 446 if (pcb->pcb_onfault) { 447 tf->tf_r0 = EINVAL; 448 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 449 return; 450 } 451 printf("\nNon-emulated page fault with intr_depth > 0\n"); 452 dab_fatal(tf, fsr, far, l, NULL); 453 } 454 455 onfault = pcb->pcb_onfault; 456 pcb->pcb_onfault = NULL; 457 error = uvm_fault(map, va, ftype); 458 pcb->pcb_onfault = onfault; 459 460 if (__predict_true(error == 0)) { 461 if (user) 462 uvm_grow(l->l_proc, va); /* Record any stack growth */ 463 UVMHIST_LOG(maphist, " <- uvm", 0, 0, 0, 0); 464 goto out; 465 } 466 467 if (user == 0) { 468 if (pcb->pcb_onfault) { 469 tf->tf_r0 = error; 470 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 471 return; 472 } 473 474 printf("\nuvm_fault(%p, %lx, %x) -> %x\n", map, va, ftype, 475 error); 476 dab_fatal(tf, fsr, far, l, NULL); 477 } 478 479 KSI_INIT_TRAP(&ksi); 480 481 if (error == ENOMEM) { 482 printf("UVM: pid %d (%s), uid %d killed: " 483 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 484 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 485 ksi.ksi_signo = SIGKILL; 486 } else 487 ksi.ksi_signo = SIGSEGV; 488 489 ksi.ksi_code = (error == EACCES) ? SEGV_ACCERR : SEGV_MAPERR; 490 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 491 ksi.ksi_trap = fsr; 492 UVMHIST_LOG(maphist, " <- erorr (%d)", error, 0, 0, 0); 493 494 do_trapsignal: 495 call_trapsignal(l, &ksi); 496 out: 497 /* If returning to user mode, make sure to invoke userret() */ 498 if (user) 499 userret(l); 500 } 501 502 /* 503 * dab_fatal() handles the following data aborts: 504 * 505 * FAULT_WRTBUF_0 - Vector Exception 506 * FAULT_WRTBUF_1 - Terminal Exception 507 * 508 * We should never see these on a properly functioning system. 509 * 510 * This function is also called by the other handlers if they 511 * detect a fatal problem. 512 * 513 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 514 */ 515 static int 516 dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 517 { 518 const char *mode; 519 520 mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 521 522 if (l != NULL) { 523 printf("Fatal %s mode data abort: '%s'\n", mode, 524 data_aborts[fsr & FAULT_TYPE_MASK].desc); 525 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 526 if ((fsr & FAULT_IMPRECISE) == 0) 527 printf("%08x, ", far); 528 else 529 printf("Invalid, "); 530 printf("spsr=%08x\n", tf->tf_spsr); 531 } else { 532 printf("Fatal %s mode prefetch abort at 0x%08x\n", 533 mode, tf->tf_pc); 534 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 535 } 536 537 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 538 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 539 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 540 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 541 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 542 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 543 printf("r12=%08x, ", tf->tf_r12); 544 545 if (TRAP_USERMODE(tf)) 546 printf("usp=%08x, ulr=%08x", 547 tf->tf_usr_sp, tf->tf_usr_lr); 548 else 549 printf("ssp=%08x, slr=%08x", 550 tf->tf_svc_sp, tf->tf_svc_lr); 551 printf(", pc =%08x\n\n", tf->tf_pc); 552 553 #if defined(DDB) || defined(KGDB) 554 kdb_trap(T_FAULT, tf); 555 #endif 556 panic("Fatal abort"); 557 /*NOTREACHED*/ 558 } 559 560 /* 561 * dab_align() handles the following data aborts: 562 * 563 * FAULT_ALIGN_0 - Alignment fault 564 * FAULT_ALIGN_0 - Alignment fault 565 * 566 * These faults are fatal if they happen in kernel mode. Otherwise, we 567 * deliver a bus error to the process. 568 */ 569 static int 570 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 571 { 572 573 /* Alignment faults are always fatal if they occur in kernel mode */ 574 if (!TRAP_USERMODE(tf)) 575 dab_fatal(tf, fsr, far, l, NULL); 576 577 /* pcb_onfault *must* be NULL at this point */ 578 KDASSERT(l->l_addr->u_pcb.pcb_onfault == NULL); 579 580 /* See if the CPU state needs to be fixed up */ 581 (void) data_abort_fixup(tf, fsr, far, l); 582 583 /* Deliver a bus error signal to the process */ 584 KSI_INIT_TRAP(ksi); 585 ksi->ksi_signo = SIGBUS; 586 ksi->ksi_code = BUS_ADRALN; 587 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 588 ksi->ksi_trap = fsr; 589 590 l->l_addr->u_pcb.pcb_tf = tf; 591 592 return (1); 593 } 594 595 /* 596 * dab_buserr() handles the following data aborts: 597 * 598 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 599 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 600 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 601 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 602 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 603 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 604 * 605 * If pcb_onfault is set, flag the fault and return to the handler. 606 * If the fault occurred in user mode, give the process a SIGBUS. 607 * 608 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 609 * can be flagged as imprecise in the FSR. This causes a real headache 610 * since some of the machine state is lost. In this case, tf->tf_pc 611 * may not actually point to the offending instruction. In fact, if 612 * we've taken a double abort fault, it generally points somewhere near 613 * the top of "data_abort_entry" in exception.S. 614 * 615 * In all other cases, these data aborts are considered fatal. 616 */ 617 static int 618 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 619 ksiginfo_t *ksi) 620 { 621 struct pcb *pcb = &l->l_addr->u_pcb; 622 623 #ifdef __XSCALE__ 624 if ((fsr & FAULT_IMPRECISE) != 0 && 625 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 626 /* 627 * Oops, an imprecise, double abort fault. We've lost the 628 * r14_abt/spsr_abt values corresponding to the original 629 * abort, and the spsr saved in the trapframe indicates 630 * ABT mode. 631 */ 632 tf->tf_spsr &= ~PSR_MODE; 633 634 /* 635 * We use a simple heuristic to determine if the double abort 636 * happened as a result of a kernel or user mode access. 637 * If the current trapframe is at the top of the kernel stack, 638 * the fault _must_ have come from user mode. 639 */ 640 if (tf != ((trapframe_t *)pcb->pcb_un.un_32.pcb32_sp) - 1) { 641 /* 642 * Kernel mode. We're either about to die a 643 * spectacular death, or pcb_onfault will come 644 * to our rescue. Either way, the current value 645 * of tf->tf_pc is irrelevant. 646 */ 647 tf->tf_spsr |= PSR_SVC32_MODE; 648 if (pcb->pcb_onfault == NULL) 649 printf("\nKernel mode double abort!\n"); 650 } else { 651 /* 652 * User mode. We've lost the program counter at the 653 * time of the fault (not that it was accurate anyway; 654 * it's not called an imprecise fault for nothing). 655 * About all we can do is copy r14_usr to tf_pc and 656 * hope for the best. The process is about to get a 657 * SIGBUS, so it's probably history anyway. 658 */ 659 tf->tf_spsr |= PSR_USR32_MODE; 660 tf->tf_pc = tf->tf_usr_lr; 661 #ifdef THUMB_CODE 662 tf->tf_spsr &= ~PSR_T_bit; 663 if (tf->tf_usr_lr & 1) 664 tf->tf_spsr |= PSR_T_bit; 665 #endif 666 } 667 } 668 669 /* FAR is invalid for imprecise exceptions */ 670 if ((fsr & FAULT_IMPRECISE) != 0) 671 far = 0; 672 #endif /* __XSCALE__ */ 673 674 if (pcb->pcb_onfault) { 675 KDASSERT(TRAP_USERMODE(tf) == 0); 676 tf->tf_r0 = EFAULT; 677 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 678 return (0); 679 } 680 681 /* See if the CPU state needs to be fixed up */ 682 (void) data_abort_fixup(tf, fsr, far, l); 683 684 /* 685 * At this point, if the fault happened in kernel mode, we're toast 686 */ 687 if (!TRAP_USERMODE(tf)) 688 dab_fatal(tf, fsr, far, l, NULL); 689 690 /* Deliver a bus error signal to the process */ 691 KSI_INIT_TRAP(ksi); 692 ksi->ksi_signo = SIGBUS; 693 ksi->ksi_code = BUS_ADRERR; 694 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 695 ksi->ksi_trap = fsr; 696 697 l->l_addr->u_pcb.pcb_tf = tf; 698 699 return (1); 700 } 701 702 static inline int 703 prefetch_abort_fixup(trapframe_t *tf) 704 { 705 #ifdef CPU_ABORT_FIXUP_REQUIRED 706 int error; 707 708 /* Call the CPU specific prefetch abort fixup routine */ 709 error = cpu_prefetchabt_fixup(tf); 710 if (__predict_true(error != ABORT_FIXUP_FAILED)) 711 return (error); 712 713 /* 714 * Oops, couldn't fix up the instruction 715 */ 716 printf( 717 "prefetch_abort_fixup: fixup for %s mode prefetch abort failed.\n", 718 TRAP_USERMODE(tf) ? "user" : "kernel"); 719 #ifdef THUMB_CODE 720 if (tf->tf_spsr & PSR_T_bit) { 721 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 722 tf->tf_pc, *((u_int16 *)(tf->tf_pc & ~1), 723 *((u_int16 *)((tf->tf_pc + 2) & ~1)); 724 } 725 else 726 #endif 727 { 728 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 729 *((u_int *)tf->tf_pc)); 730 } 731 disassemble(tf->tf_pc); 732 733 /* Die now if this happened in kernel mode */ 734 if (!TRAP_USERMODE(tf)) 735 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 736 737 return (error); 738 #else 739 return (ABORT_FIXUP_OK); 740 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 741 } 742 743 /* 744 * void prefetch_abort_handler(trapframe_t *tf) 745 * 746 * Abort handler called when instruction execution occurs at 747 * a non existent or restricted (access permissions) memory page. 748 * If the address is invalid and we were in SVC mode then panic as 749 * the kernel should never prefetch abort. 750 * If the address is invalid and the page is mapped then the user process 751 * does no have read permission so send it a signal. 752 * Otherwise fault the page in and try again. 753 */ 754 void 755 prefetch_abort_handler(trapframe_t *tf) 756 { 757 struct lwp *l; 758 struct vm_map *map; 759 vaddr_t fault_pc, va; 760 ksiginfo_t ksi; 761 int error, user; 762 763 UVMHIST_FUNC("prefetch_abort_handler"); UVMHIST_CALLED(maphist); 764 765 /* Update vmmeter statistics */ 766 uvmexp.traps++; 767 768 l = curlwp; 769 770 if ((user = TRAP_USERMODE(tf)) != 0) 771 LWP_CACHE_CREDS(l, l->l_proc); 772 773 /* 774 * Enable IRQ's (disabled by the abort) This always comes 775 * from user mode so we know interrupts were not disabled. 776 * But we check anyway. 777 */ 778 if (__predict_true((tf->tf_spsr & I32_bit) == 0)) 779 enable_interrupts(I32_bit); 780 781 /* See if the CPU state needs to be fixed up */ 782 switch (prefetch_abort_fixup(tf)) { 783 case ABORT_FIXUP_RETURN: 784 return; 785 case ABORT_FIXUP_FAILED: 786 /* Deliver a SIGILL to the process */ 787 KSI_INIT_TRAP(&ksi); 788 ksi.ksi_signo = SIGILL; 789 ksi.ksi_code = ILL_ILLOPC; 790 ksi.ksi_addr = (u_int32_t *)(intptr_t) tf->tf_pc; 791 l->l_addr->u_pcb.pcb_tf = tf; 792 goto do_trapsignal; 793 default: 794 break; 795 } 796 797 /* Prefetch aborts cannot happen in kernel mode */ 798 if (__predict_false(!user)) 799 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 800 801 /* Get fault address */ 802 fault_pc = tf->tf_pc; 803 l = curlwp; 804 l->l_addr->u_pcb.pcb_tf = tf; 805 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, tf=0x%x)", fault_pc, l, tf, 806 0); 807 808 /* Ok validate the address, can only execute in USER space */ 809 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 810 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 811 KSI_INIT_TRAP(&ksi); 812 ksi.ksi_signo = SIGSEGV; 813 ksi.ksi_code = SEGV_ACCERR; 814 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 815 ksi.ksi_trap = fault_pc; 816 goto do_trapsignal; 817 } 818 819 map = &l->l_proc->p_vmspace->vm_map; 820 va = trunc_page(fault_pc); 821 822 /* 823 * See if the pmap can handle this fault on its own... 824 */ 825 #ifdef DEBUG 826 last_fault_code = -1; 827 #endif 828 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1)) { 829 UVMHIST_LOG (maphist, " <- emulated", 0, 0, 0, 0); 830 goto out; 831 } 832 833 #ifdef DIAGNOSTIC 834 if (__predict_false(l->l_cpu->ci_intr_depth > 0)) { 835 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 836 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 837 } 838 #endif 839 error = uvm_fault(map, va, VM_PROT_READ); 840 841 if (__predict_true(error == 0)) { 842 UVMHIST_LOG (maphist, " <- uvm", 0, 0, 0, 0); 843 goto out; 844 } 845 KSI_INIT_TRAP(&ksi); 846 847 UVMHIST_LOG (maphist, " <- fatal (%d)", error, 0, 0, 0); 848 if (error == ENOMEM) { 849 printf("UVM: pid %d (%s), uid %d killed: " 850 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 851 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 852 ksi.ksi_signo = SIGKILL; 853 } else 854 ksi.ksi_signo = SIGSEGV; 855 856 ksi.ksi_code = SEGV_MAPERR; 857 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 858 ksi.ksi_trap = fault_pc; 859 860 do_trapsignal: 861 call_trapsignal(l, &ksi); 862 863 out: 864 userret(l); 865 } 866 867 /* 868 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 869 * If the read succeeds, the value is written to 'rptr' and zero is returned. 870 * Else, return EFAULT. 871 */ 872 int 873 badaddr_read(void *addr, size_t size, void *rptr) 874 { 875 extern int badaddr_read_1(const uint8_t *, uint8_t *); 876 extern int badaddr_read_2(const uint16_t *, uint16_t *); 877 extern int badaddr_read_4(const uint32_t *, uint32_t *); 878 union { 879 uint8_t v1; 880 uint16_t v2; 881 uint32_t v4; 882 } u; 883 struct pcb *curpcb_save; 884 int rv, s; 885 886 cpu_drain_writebuf(); 887 888 /* 889 * We might be called at interrupt time, so arrange to steal 890 * lwp0's PCB temporarily, if required, so that pcb_onfault 891 * handling works correctly. 892 */ 893 s = splhigh(); 894 if ((curpcb_save = curpcb) == NULL) 895 curpcb = &lwp0.l_addr->u_pcb; 896 897 /* Read from the test address. */ 898 switch (size) { 899 case sizeof(uint8_t): 900 rv = badaddr_read_1(addr, &u.v1); 901 if (rv == 0 && rptr) 902 *(uint8_t *) rptr = u.v1; 903 break; 904 905 case sizeof(uint16_t): 906 rv = badaddr_read_2(addr, &u.v2); 907 if (rv == 0 && rptr) 908 *(uint16_t *) rptr = u.v2; 909 break; 910 911 case sizeof(uint32_t): 912 rv = badaddr_read_4(addr, &u.v4); 913 if (rv == 0 && rptr) 914 *(uint32_t *) rptr = u.v4; 915 break; 916 917 default: 918 curpcb = curpcb_save; 919 panic("badaddr: invalid size (%lu)", (u_long) size); 920 } 921 922 /* Restore curpcb */ 923 curpcb = curpcb_save; 924 splx(s); 925 926 /* Return EFAULT if the address was invalid, else zero */ 927 return (rv); 928 } 929