1 /* $NetBSD: fault.c,v 1.67 2008/04/27 18:58:44 matt 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 1.67 2008/04/27 18:58:44 matt 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 KERNEL_LOCK(1, l); 178 TRAPSIGNAL(l, ksi); 179 KERNEL_UNLOCK_LAST(l); 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 if (__predict_true((tf->tf_spsr & I32_bit) == 0)) 247 enable_interrupts(I32_bit); 248 249 /* Get the current lwp structure */ 250 KASSERT(curlwp != NULL); 251 l = curlwp; 252 253 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, far=0x%x, fsr=0x%x)", 254 tf->tf_pc, l, far, fsr); 255 256 /* Data abort came from user mode? */ 257 if ((user = TRAP_USERMODE(tf)) != 0) 258 LWP_CACHE_CREDS(l, l->l_proc); 259 260 /* Grab the current pcb */ 261 pcb = &l->l_addr->u_pcb; 262 263 /* Invoke the appropriate handler, if necessary */ 264 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 265 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, 266 l, &ksi)) 267 goto do_trapsignal; 268 goto out; 269 } 270 271 /* 272 * At this point, we're dealing with one of the following data aborts: 273 * 274 * FAULT_TRANS_S - Translation -- Section 275 * FAULT_TRANS_P - Translation -- Page 276 * FAULT_DOMAIN_S - Domain -- Section 277 * FAULT_DOMAIN_P - Domain -- Page 278 * FAULT_PERM_S - Permission -- Section 279 * FAULT_PERM_P - Permission -- Page 280 * 281 * These are the main virtual memory-related faults signalled by 282 * the MMU. 283 */ 284 285 /* fusubailout is used by [fs]uswintr to avoid page faulting */ 286 if (__predict_false(pcb->pcb_onfault == fusubailout)) { 287 tf->tf_r0 = EFAULT; 288 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 289 return; 290 } 291 292 if (user) 293 l->l_addr->u_pcb.pcb_tf = tf; 294 295 /* 296 * Make sure the Program Counter is sane. We could fall foul of 297 * someone executing Thumb code, in which case the PC might not 298 * be word-aligned. This would cause a kernel alignment fault 299 * further down if we have to decode the current instruction. 300 */ 301 #ifdef THUMB_CODE 302 /* 303 * XXX: It would be nice to be able to support Thumb in the kernel 304 * at some point. 305 */ 306 if (__predict_false(!user && (tf->tf_pc & 3) != 0)) { 307 printf("\ndata_abort_fault: Misaligned Kernel-mode " 308 "Program Counter\n"); 309 dab_fatal(tf, fsr, far, l, NULL); 310 } 311 #else 312 if (__predict_false((tf->tf_pc & 3) != 0)) { 313 if (user) { 314 /* 315 * Give the user an illegal instruction signal. 316 */ 317 /* Deliver a SIGILL to the process */ 318 KSI_INIT_TRAP(&ksi); 319 ksi.ksi_signo = SIGILL; 320 ksi.ksi_code = ILL_ILLOPC; 321 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 322 ksi.ksi_trap = fsr; 323 goto do_trapsignal; 324 } 325 326 /* 327 * The kernel never executes Thumb code. 328 */ 329 printf("\ndata_abort_fault: Misaligned Kernel-mode " 330 "Program Counter\n"); 331 dab_fatal(tf, fsr, far, l, NULL); 332 } 333 #endif 334 335 /* See if the CPU state needs to be fixed up */ 336 switch (data_abort_fixup(tf, fsr, far, l)) { 337 case ABORT_FIXUP_RETURN: 338 return; 339 case ABORT_FIXUP_FAILED: 340 /* Deliver a SIGILL to the process */ 341 KSI_INIT_TRAP(&ksi); 342 ksi.ksi_signo = SIGILL; 343 ksi.ksi_code = ILL_ILLOPC; 344 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 345 ksi.ksi_trap = fsr; 346 goto do_trapsignal; 347 default: 348 break; 349 } 350 351 va = trunc_page((vaddr_t)far); 352 353 /* 354 * It is only a kernel address space fault iff: 355 * 1. user == 0 and 356 * 2. pcb_onfault not set or 357 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. 358 */ 359 if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS || 360 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && 361 __predict_true((pcb->pcb_onfault == NULL || 362 (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) { 363 map = kernel_map; 364 365 /* Was the fault due to the FPE/IPKDB ? */ 366 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { 367 KSI_INIT_TRAP(&ksi); 368 ksi.ksi_signo = SIGSEGV; 369 ksi.ksi_code = SEGV_ACCERR; 370 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 371 ksi.ksi_trap = fsr; 372 373 /* 374 * Force exit via userret() 375 * This is necessary as the FPE is an extension to 376 * userland that actually runs in a priveledged mode 377 * but uses USR mode permissions for its accesses. 378 */ 379 user = 1; 380 goto do_trapsignal; 381 } 382 } else 383 map = &l->l_proc->p_vmspace->vm_map; 384 385 /* 386 * We need to know whether the page should be mapped 387 * as R or R/W. The MMU does not give us the info as 388 * to whether the fault was caused by a read or a write. 389 * 390 * However, we know that a permission fault can only be 391 * the result of a write to a read-only location, so 392 * we can deal with those quickly. 393 * 394 * Otherwise we need to disassemble the instruction 395 * responsible to determine if it was a write. 396 */ 397 if (IS_PERMISSION_FAULT(fsr)) 398 ftype = VM_PROT_WRITE; 399 else { 400 #ifdef THUMB_CODE 401 /* Fast track the ARM case. */ 402 if (__predict_false(tf->tf_spsr & PSR_T_bit)) { 403 u_int insn = fusword((void *)(tf->tf_pc & ~1)); 404 u_int insn_f8 = insn & 0xf800; 405 u_int insn_fe = insn & 0xfe00; 406 407 if (insn_f8 == 0x6000 || /* STR(1) */ 408 insn_f8 == 0x7000 || /* STRB(1) */ 409 insn_f8 == 0x8000 || /* STRH(1) */ 410 insn_f8 == 0x9000 || /* STR(3) */ 411 insn_f8 == 0xc000 || /* STM */ 412 insn_fe == 0x5000 || /* STR(2) */ 413 insn_fe == 0x5200 || /* STRH(2) */ 414 insn_fe == 0x5400) /* STRB(2) */ 415 ftype = VM_PROT_WRITE; 416 else 417 ftype = VM_PROT_READ; 418 } 419 else 420 #endif 421 { 422 u_int insn = ReadWord(tf->tf_pc); 423 424 if (((insn & 0x0c100000) == 0x04000000) || /* STR[B] */ 425 ((insn & 0x0e1000b0) == 0x000000b0) || /* STR[HD]*/ 426 ((insn & 0x0a100000) == 0x08000000)) /* STM/CDT*/ 427 ftype = VM_PROT_WRITE; 428 else if ((insn & 0x0fb00ff0) == 0x01000090)/* SWP */ 429 ftype = VM_PROT_READ | VM_PROT_WRITE; 430 else 431 ftype = VM_PROT_READ; 432 } 433 } 434 435 /* 436 * See if the fault is as a result of ref/mod emulation, 437 * or domain mismatch. 438 */ 439 #ifdef DEBUG 440 last_fault_code = fsr; 441 #endif 442 if (pmap_fault_fixup(map->pmap, va, ftype, user)) { 443 UVMHIST_LOG(maphist, " <- ref/mod emul", 0, 0, 0, 0); 444 goto out; 445 } 446 447 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 448 if (pcb->pcb_onfault) { 449 tf->tf_r0 = EINVAL; 450 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 451 return; 452 } 453 printf("\nNon-emulated page fault with intr_depth > 0\n"); 454 dab_fatal(tf, fsr, far, l, NULL); 455 } 456 457 onfault = pcb->pcb_onfault; 458 pcb->pcb_onfault = NULL; 459 error = uvm_fault(map, va, ftype); 460 pcb->pcb_onfault = onfault; 461 462 if (__predict_true(error == 0)) { 463 if (user) 464 uvm_grow(l->l_proc, va); /* Record any stack growth */ 465 UVMHIST_LOG(maphist, " <- uvm", 0, 0, 0, 0); 466 goto out; 467 } 468 469 if (user == 0) { 470 if (pcb->pcb_onfault) { 471 tf->tf_r0 = error; 472 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 473 return; 474 } 475 476 printf("\nuvm_fault(%p, %lx, %x) -> %x\n", map, va, ftype, 477 error); 478 dab_fatal(tf, fsr, far, l, NULL); 479 } 480 481 KSI_INIT_TRAP(&ksi); 482 483 if (error == ENOMEM) { 484 printf("UVM: pid %d (%s), uid %d killed: " 485 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 486 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 487 ksi.ksi_signo = SIGKILL; 488 } else 489 ksi.ksi_signo = SIGSEGV; 490 491 ksi.ksi_code = (error == EACCES) ? SEGV_ACCERR : SEGV_MAPERR; 492 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 493 ksi.ksi_trap = fsr; 494 UVMHIST_LOG(maphist, " <- erorr (%d)", error, 0, 0, 0); 495 496 do_trapsignal: 497 call_trapsignal(l, &ksi); 498 out: 499 /* If returning to user mode, make sure to invoke userret() */ 500 if (user) 501 userret(l); 502 } 503 504 /* 505 * dab_fatal() handles the following data aborts: 506 * 507 * FAULT_WRTBUF_0 - Vector Exception 508 * FAULT_WRTBUF_1 - Terminal Exception 509 * 510 * We should never see these on a properly functioning system. 511 * 512 * This function is also called by the other handlers if they 513 * detect a fatal problem. 514 * 515 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 516 */ 517 static int 518 dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 519 { 520 const char *mode; 521 522 mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 523 524 if (l != NULL) { 525 printf("Fatal %s mode data abort: '%s'\n", mode, 526 data_aborts[fsr & FAULT_TYPE_MASK].desc); 527 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 528 if ((fsr & FAULT_IMPRECISE) == 0) 529 printf("%08x, ", far); 530 else 531 printf("Invalid, "); 532 printf("spsr=%08x\n", tf->tf_spsr); 533 } else { 534 printf("Fatal %s mode prefetch abort at 0x%08x\n", 535 mode, tf->tf_pc); 536 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 537 } 538 539 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 540 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 541 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 542 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 543 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 544 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 545 printf("r12=%08x, ", tf->tf_r12); 546 547 if (TRAP_USERMODE(tf)) 548 printf("usp=%08x, ulr=%08x", 549 tf->tf_usr_sp, tf->tf_usr_lr); 550 else 551 printf("ssp=%08x, slr=%08x", 552 tf->tf_svc_sp, tf->tf_svc_lr); 553 printf(", pc =%08x\n\n", tf->tf_pc); 554 555 #if defined(DDB) || defined(KGDB) 556 kdb_trap(T_FAULT, tf); 557 #endif 558 panic("Fatal abort"); 559 /*NOTREACHED*/ 560 } 561 562 /* 563 * dab_align() handles the following data aborts: 564 * 565 * FAULT_ALIGN_0 - Alignment fault 566 * FAULT_ALIGN_0 - Alignment fault 567 * 568 * These faults are fatal if they happen in kernel mode. Otherwise, we 569 * deliver a bus error to the process. 570 */ 571 static int 572 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 573 { 574 575 /* Alignment faults are always fatal if they occur in kernel mode */ 576 if (!TRAP_USERMODE(tf)) 577 dab_fatal(tf, fsr, far, l, NULL); 578 579 /* pcb_onfault *must* be NULL at this point */ 580 KDASSERT(l->l_addr->u_pcb.pcb_onfault == NULL); 581 582 /* See if the CPU state needs to be fixed up */ 583 (void) data_abort_fixup(tf, fsr, far, l); 584 585 /* Deliver a bus error signal to the process */ 586 KSI_INIT_TRAP(ksi); 587 ksi->ksi_signo = SIGBUS; 588 ksi->ksi_code = BUS_ADRALN; 589 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 590 ksi->ksi_trap = fsr; 591 592 l->l_addr->u_pcb.pcb_tf = tf; 593 594 return (1); 595 } 596 597 /* 598 * dab_buserr() handles the following data aborts: 599 * 600 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 601 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 602 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 603 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 604 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 605 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 606 * 607 * If pcb_onfault is set, flag the fault and return to the handler. 608 * If the fault occurred in user mode, give the process a SIGBUS. 609 * 610 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 611 * can be flagged as imprecise in the FSR. This causes a real headache 612 * since some of the machine state is lost. In this case, tf->tf_pc 613 * may not actually point to the offending instruction. In fact, if 614 * we've taken a double abort fault, it generally points somewhere near 615 * the top of "data_abort_entry" in exception.S. 616 * 617 * In all other cases, these data aborts are considered fatal. 618 */ 619 static int 620 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 621 ksiginfo_t *ksi) 622 { 623 struct pcb *pcb = &l->l_addr->u_pcb; 624 625 #ifdef __XSCALE__ 626 if ((fsr & FAULT_IMPRECISE) != 0 && 627 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 628 /* 629 * Oops, an imprecise, double abort fault. We've lost the 630 * r14_abt/spsr_abt values corresponding to the original 631 * abort, and the spsr saved in the trapframe indicates 632 * ABT mode. 633 */ 634 tf->tf_spsr &= ~PSR_MODE; 635 636 /* 637 * We use a simple heuristic to determine if the double abort 638 * happened as a result of a kernel or user mode access. 639 * If the current trapframe is at the top of the kernel stack, 640 * the fault _must_ have come from user mode. 641 */ 642 if (tf != ((trapframe_t *)pcb->pcb_un.un_32.pcb32_sp) - 1) { 643 /* 644 * Kernel mode. We're either about to die a 645 * spectacular death, or pcb_onfault will come 646 * to our rescue. Either way, the current value 647 * of tf->tf_pc is irrelevant. 648 */ 649 tf->tf_spsr |= PSR_SVC32_MODE; 650 if (pcb->pcb_onfault == NULL) 651 printf("\nKernel mode double abort!\n"); 652 } else { 653 /* 654 * User mode. We've lost the program counter at the 655 * time of the fault (not that it was accurate anyway; 656 * it's not called an imprecise fault for nothing). 657 * About all we can do is copy r14_usr to tf_pc and 658 * hope for the best. The process is about to get a 659 * SIGBUS, so it's probably history anyway. 660 */ 661 tf->tf_spsr |= PSR_USR32_MODE; 662 tf->tf_pc = tf->tf_usr_lr; 663 #ifdef THUMB_CODE 664 tf->tf_spsr &= ~PSR_T_bit; 665 if (tf->tf_usr_lr & 1) 666 tf->tf_spsr |= PSR_T_bit; 667 #endif 668 } 669 } 670 671 /* FAR is invalid for imprecise exceptions */ 672 if ((fsr & FAULT_IMPRECISE) != 0) 673 far = 0; 674 #endif /* __XSCALE__ */ 675 676 if (pcb->pcb_onfault) { 677 KDASSERT(TRAP_USERMODE(tf) == 0); 678 tf->tf_r0 = EFAULT; 679 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 680 return (0); 681 } 682 683 /* See if the CPU state needs to be fixed up */ 684 (void) data_abort_fixup(tf, fsr, far, l); 685 686 /* 687 * At this point, if the fault happened in kernel mode, we're toast 688 */ 689 if (!TRAP_USERMODE(tf)) 690 dab_fatal(tf, fsr, far, l, NULL); 691 692 /* Deliver a bus error signal to the process */ 693 KSI_INIT_TRAP(ksi); 694 ksi->ksi_signo = SIGBUS; 695 ksi->ksi_code = BUS_ADRERR; 696 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 697 ksi->ksi_trap = fsr; 698 699 l->l_addr->u_pcb.pcb_tf = tf; 700 701 return (1); 702 } 703 704 static inline int 705 prefetch_abort_fixup(trapframe_t *tf) 706 { 707 #ifdef CPU_ABORT_FIXUP_REQUIRED 708 int error; 709 710 /* Call the CPU specific prefetch abort fixup routine */ 711 error = cpu_prefetchabt_fixup(tf); 712 if (__predict_true(error != ABORT_FIXUP_FAILED)) 713 return (error); 714 715 /* 716 * Oops, couldn't fix up the instruction 717 */ 718 printf( 719 "prefetch_abort_fixup: fixup for %s mode prefetch abort failed.\n", 720 TRAP_USERMODE(tf) ? "user" : "kernel"); 721 #ifdef THUMB_CODE 722 if (tf->tf_spsr & PSR_T_bit) { 723 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 724 tf->tf_pc, *((u_int16 *)(tf->tf_pc & ~1), 725 *((u_int16 *)((tf->tf_pc + 2) & ~1)); 726 } 727 else 728 #endif 729 { 730 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 731 *((u_int *)tf->tf_pc)); 732 } 733 disassemble(tf->tf_pc); 734 735 /* Die now if this happened in kernel mode */ 736 if (!TRAP_USERMODE(tf)) 737 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 738 739 return (error); 740 #else 741 return (ABORT_FIXUP_OK); 742 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 743 } 744 745 /* 746 * void prefetch_abort_handler(trapframe_t *tf) 747 * 748 * Abort handler called when instruction execution occurs at 749 * a non existent or restricted (access permissions) memory page. 750 * If the address is invalid and we were in SVC mode then panic as 751 * the kernel should never prefetch abort. 752 * If the address is invalid and the page is mapped then the user process 753 * does no have read permission so send it a signal. 754 * Otherwise fault the page in and try again. 755 */ 756 void 757 prefetch_abort_handler(trapframe_t *tf) 758 { 759 struct lwp *l; 760 struct vm_map *map; 761 vaddr_t fault_pc, va; 762 ksiginfo_t ksi; 763 int error, user; 764 765 UVMHIST_FUNC("prefetch_abort_handler"); UVMHIST_CALLED(maphist); 766 767 /* Update vmmeter statistics */ 768 uvmexp.traps++; 769 770 l = curlwp; 771 772 if ((user = TRAP_USERMODE(tf)) != 0) 773 LWP_CACHE_CREDS(l, l->l_proc); 774 775 /* 776 * Enable IRQ's (disabled by the abort) This always comes 777 * from user mode so we know interrupts were not disabled. 778 * But we check anyway. 779 */ 780 if (__predict_true((tf->tf_spsr & I32_bit) == 0)) 781 enable_interrupts(I32_bit); 782 783 /* See if the CPU state needs to be fixed up */ 784 switch (prefetch_abort_fixup(tf)) { 785 case ABORT_FIXUP_RETURN: 786 return; 787 case ABORT_FIXUP_FAILED: 788 /* Deliver a SIGILL to the process */ 789 KSI_INIT_TRAP(&ksi); 790 ksi.ksi_signo = SIGILL; 791 ksi.ksi_code = ILL_ILLOPC; 792 ksi.ksi_addr = (u_int32_t *)(intptr_t) tf->tf_pc; 793 l->l_addr->u_pcb.pcb_tf = tf; 794 goto do_trapsignal; 795 default: 796 break; 797 } 798 799 /* Prefetch aborts cannot happen in kernel mode */ 800 if (__predict_false(!user)) 801 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 802 803 /* Get fault address */ 804 fault_pc = tf->tf_pc; 805 l = curlwp; 806 l->l_addr->u_pcb.pcb_tf = tf; 807 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, tf=0x%x)", fault_pc, l, tf, 808 0); 809 810 /* Ok validate the address, can only execute in USER space */ 811 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 812 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 813 KSI_INIT_TRAP(&ksi); 814 ksi.ksi_signo = SIGSEGV; 815 ksi.ksi_code = SEGV_ACCERR; 816 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 817 ksi.ksi_trap = fault_pc; 818 goto do_trapsignal; 819 } 820 821 map = &l->l_proc->p_vmspace->vm_map; 822 va = trunc_page(fault_pc); 823 824 /* 825 * See if the pmap can handle this fault on its own... 826 */ 827 #ifdef DEBUG 828 last_fault_code = -1; 829 #endif 830 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1)) { 831 UVMHIST_LOG (maphist, " <- emulated", 0, 0, 0, 0); 832 goto out; 833 } 834 835 #ifdef DIAGNOSTIC 836 if (__predict_false(l->l_cpu->ci_intr_depth > 0)) { 837 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 838 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 839 } 840 #endif 841 error = uvm_fault(map, va, VM_PROT_READ); 842 843 if (__predict_true(error == 0)) { 844 UVMHIST_LOG (maphist, " <- uvm", 0, 0, 0, 0); 845 goto out; 846 } 847 KSI_INIT_TRAP(&ksi); 848 849 UVMHIST_LOG (maphist, " <- fatal (%d)", error, 0, 0, 0); 850 if (error == ENOMEM) { 851 printf("UVM: pid %d (%s), uid %d killed: " 852 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 853 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 854 ksi.ksi_signo = SIGKILL; 855 } else 856 ksi.ksi_signo = SIGSEGV; 857 858 ksi.ksi_code = SEGV_MAPERR; 859 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 860 ksi.ksi_trap = fault_pc; 861 862 do_trapsignal: 863 call_trapsignal(l, &ksi); 864 865 out: 866 userret(l); 867 } 868 869 /* 870 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 871 * If the read succeeds, the value is written to 'rptr' and zero is returned. 872 * Else, return EFAULT. 873 */ 874 int 875 badaddr_read(void *addr, size_t size, void *rptr) 876 { 877 extern int badaddr_read_1(const uint8_t *, uint8_t *); 878 extern int badaddr_read_2(const uint16_t *, uint16_t *); 879 extern int badaddr_read_4(const uint32_t *, uint32_t *); 880 union { 881 uint8_t v1; 882 uint16_t v2; 883 uint32_t v4; 884 } u; 885 struct pcb *curpcb_save; 886 int rv, s; 887 888 cpu_drain_writebuf(); 889 890 /* 891 * We might be called at interrupt time, so arrange to steal 892 * lwp0's PCB temporarily, if required, so that pcb_onfault 893 * handling works correctly. 894 */ 895 s = splhigh(); 896 if ((curpcb_save = curpcb) == NULL) 897 curpcb = &lwp0.l_addr->u_pcb; 898 899 /* Read from the test address. */ 900 switch (size) { 901 case sizeof(uint8_t): 902 rv = badaddr_read_1(addr, &u.v1); 903 if (rv == 0 && rptr) 904 *(uint8_t *) rptr = u.v1; 905 break; 906 907 case sizeof(uint16_t): 908 rv = badaddr_read_2(addr, &u.v2); 909 if (rv == 0 && rptr) 910 *(uint16_t *) rptr = u.v2; 911 break; 912 913 case sizeof(uint32_t): 914 rv = badaddr_read_4(addr, &u.v4); 915 if (rv == 0 && rptr) 916 *(uint32_t *) rptr = u.v4; 917 break; 918 919 default: 920 curpcb = curpcb_save; 921 panic("badaddr: invalid size (%lu)", (u_long) size); 922 } 923 924 /* Restore curpcb */ 925 curpcb = curpcb_save; 926 splx(s); 927 928 /* Return EFAULT if the address was invalid, else zero */ 929 return (rv); 930 } 931