1 /* $NetBSD: fault.c,v 1.88 2013/02/18 05:14:13 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 1.88 2013/02/18 05:14:13 matt 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 <arm/arm32/katelib.h> 102 103 #include <machine/intr.h> 104 #include <machine/pcb.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 'x' is a permission fault */ 159 #define IS_PERMISSION_FAULT(x) \ 160 (((1 << ((x) & FAULT_TYPE_MASK)) & \ 161 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) 162 163 #if 0 164 /* maybe one day we'll do emulations */ 165 #define TRAPSIGNAL(l,k) (*(l)->l_proc->p_emul->e_trapsignal)((l), (k)) 166 #else 167 #define TRAPSIGNAL(l,k) trapsignal((l), (k)) 168 #endif 169 170 static inline void 171 call_trapsignal(struct lwp *l, ksiginfo_t *ksi) 172 { 173 174 TRAPSIGNAL(l, ksi); 175 } 176 177 static inline int 178 data_abort_fixup(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l) 179 { 180 #ifdef CPU_ABORT_FIXUP_REQUIRED 181 int error; 182 183 /* Call the CPU specific data abort fixup routine */ 184 error = cpu_dataabt_fixup(tf); 185 if (__predict_true(error != ABORT_FIXUP_FAILED)) 186 return (error); 187 188 /* 189 * Oops, couldn't fix up the instruction 190 */ 191 printf("%s: fixup for %s mode data abort failed.\n", __func__, 192 TRAP_USERMODE(tf) ? "user" : "kernel"); 193 #ifdef THUMB_CODE 194 if (tf->tf_spsr & PSR_T_bit) { 195 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 196 tf->tf_pc, *((uint16 *)(tf->tf_pc & ~1)), 197 *((uint16 *)((tf->tf_pc + 2) & ~1))); 198 } 199 else 200 #endif 201 { 202 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 203 *((u_int *)tf->tf_pc)); 204 } 205 disassemble(tf->tf_pc); 206 207 /* Die now if this happened in kernel mode */ 208 if (!TRAP_USERMODE(tf)) 209 dab_fatal(tf, fsr, far, l, NULL); 210 211 return (error); 212 #else 213 return (ABORT_FIXUP_OK); 214 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 215 } 216 217 void 218 data_abort_handler(trapframe_t *tf) 219 { 220 struct vm_map *map; 221 struct lwp * const l = curlwp; 222 struct cpu_info * const ci = curcpu(); 223 u_int far, fsr; 224 vm_prot_t ftype; 225 void *onfault; 226 vaddr_t va; 227 int error; 228 ksiginfo_t ksi; 229 230 UVMHIST_FUNC("data_abort_handler"); 231 232 /* Grab FAR/FSR before enabling interrupts */ 233 far = cpu_faultaddress(); 234 fsr = cpu_faultstatus(); 235 236 UVMHIST_CALLED(maphist); 237 /* Update vmmeter statistics */ 238 ci->ci_data.cpu_ntrap++; 239 240 /* Re-enable interrupts if they were enabled previously */ 241 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 242 if (__predict_true((tf->tf_spsr & IF32_bits) != IF32_bits)) 243 restore_interrupts(tf->tf_spsr & IF32_bits); 244 245 /* Get the current lwp structure */ 246 247 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, far=0x%x, fsr=0x%x)", 248 tf->tf_pc, l, far, fsr); 249 250 /* Data abort came from user mode? */ 251 bool user = (TRAP_USERMODE(tf) != 0); 252 if (user) 253 LWP_CACHE_CREDS(l, l->l_proc); 254 255 /* Grab the current pcb */ 256 struct pcb * const pcb = lwp_getpcb(l); 257 258 curcpu()->ci_abt_evs[fsr & FAULT_TYPE_MASK].ev_count++; 259 260 /* Invoke the appropriate handler, if necessary */ 261 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 262 #ifdef DIAGNOSTIC 263 printf("%s: data_aborts fsr=0x%x far=0x%x\n", 264 __func__, fsr, far); 265 #endif 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 = (intptr_t) pcb->pcb_onfault; 290 return; 291 } 292 293 if (user) { 294 lwp_settrapframe(l, 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("\n%s: Misaligned Kernel-mode Program Counter\n", 310 __func__); 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 = (uint32_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("\n%s: Misaligned Kernel-mode Program Counter\n", 332 __func__); 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 = (uint32_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 && (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 = (uint32_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 = true; 382 goto do_trapsignal; 383 } 384 } else { 385 map = &l->l_proc->p_vmspace->vm_map; 386 } 387 388 /* 389 * We need to know whether the page should be mapped 390 * as R or R/W. The MMU does not give us the info as 391 * to whether the fault was caused by a read or a write. 392 * 393 * However, we know that a permission fault can only be 394 * the result of a write to a read-only location, so 395 * we can deal with those quickly. 396 * 397 * Otherwise we need to disassemble the instruction 398 * responsible to determine if it was a write. 399 */ 400 if (IS_PERMISSION_FAULT(fsr)) 401 ftype = VM_PROT_WRITE; 402 else { 403 #ifdef THUMB_CODE 404 /* Fast track the ARM case. */ 405 if (__predict_false(tf->tf_spsr & PSR_T_bit)) { 406 u_int insn = fusword((void *)(tf->tf_pc & ~1)); 407 u_int insn_f8 = insn & 0xf800; 408 u_int insn_fe = insn & 0xfe00; 409 410 if (insn_f8 == 0x6000 || /* STR(1) */ 411 insn_f8 == 0x7000 || /* STRB(1) */ 412 insn_f8 == 0x8000 || /* STRH(1) */ 413 insn_f8 == 0x9000 || /* STR(3) */ 414 insn_f8 == 0xc000 || /* STM */ 415 insn_fe == 0x5000 || /* STR(2) */ 416 insn_fe == 0x5200 || /* STRH(2) */ 417 insn_fe == 0x5400) /* STRB(2) */ 418 ftype = VM_PROT_WRITE; 419 else 420 ftype = VM_PROT_READ; 421 } 422 else 423 #endif 424 { 425 u_int insn = ReadWord(tf->tf_pc); 426 427 if (((insn & 0x0c100000) == 0x04000000) || /* STR[B] */ 428 ((insn & 0x0e1000b0) == 0x000000b0) || /* STR[HD]*/ 429 ((insn & 0x0a100000) == 0x08000000) || /* STM/CDT*/ 430 ((insn & 0x0f9000f0) == 0x01800090)) /* STREX[BDH] */ 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 = (uint32_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 * const mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 527 528 if (l != NULL) { 529 printf("Fatal %s mode data abort: '%s'\n", mode, 530 data_aborts[fsr & FAULT_TYPE_MASK].desc); 531 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 532 if ((fsr & FAULT_IMPRECISE) == 0) 533 printf("%08x, ", far); 534 else 535 printf("Invalid, "); 536 printf("spsr=%08x\n", tf->tf_spsr); 537 } else { 538 printf("Fatal %s mode prefetch abort at 0x%08x\n", 539 mode, tf->tf_pc); 540 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 541 } 542 543 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 544 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 545 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 546 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 547 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 548 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 549 printf("r12=%08x, ", tf->tf_r12); 550 551 if (TRAP_USERMODE(tf)) 552 printf("usp=%08x, ulr=%08x", 553 tf->tf_usr_sp, tf->tf_usr_lr); 554 else 555 printf("ssp=%08x, slr=%08x", 556 tf->tf_svc_sp, tf->tf_svc_lr); 557 printf(", pc =%08x\n\n", tf->tf_pc); 558 559 #if defined(DDB) || defined(KGDB) 560 kdb_trap(T_FAULT, tf); 561 #endif 562 panic("Fatal abort"); 563 /*NOTREACHED*/ 564 } 565 566 /* 567 * dab_align() handles the following data aborts: 568 * 569 * FAULT_ALIGN_0 - Alignment fault 570 * FAULT_ALIGN_0 - Alignment fault 571 * 572 * These faults are fatal if they happen in kernel mode. Otherwise, we 573 * deliver a bus error to the process. 574 */ 575 static int 576 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 577 { 578 /* Alignment faults are always fatal if they occur in kernel mode */ 579 if (!TRAP_USERMODE(tf)) 580 dab_fatal(tf, fsr, far, l, NULL); 581 582 /* pcb_onfault *must* be NULL at this point */ 583 KDASSERT(((struct pcb *)lwp_getpcb(l))->pcb_onfault == NULL); 584 585 /* See if the CPU state needs to be fixed up */ 586 (void) data_abort_fixup(tf, fsr, far, l); 587 588 /* Deliver a bus error signal to the process */ 589 KSI_INIT_TRAP(ksi); 590 ksi->ksi_signo = SIGBUS; 591 ksi->ksi_code = BUS_ADRALN; 592 ksi->ksi_addr = (uint32_t *)(intptr_t)far; 593 ksi->ksi_trap = fsr; 594 595 lwp_settrapframe(l, tf); 596 597 return (1); 598 } 599 600 /* 601 * dab_buserr() handles the following data aborts: 602 * 603 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 604 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 605 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 606 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 607 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 608 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 609 * 610 * If pcb_onfault is set, flag the fault and return to the handler. 611 * If the fault occurred in user mode, give the process a SIGBUS. 612 * 613 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 614 * can be flagged as imprecise in the FSR. This causes a real headache 615 * since some of the machine state is lost. In this case, tf->tf_pc 616 * may not actually point to the offending instruction. In fact, if 617 * we've taken a double abort fault, it generally points somewhere near 618 * the top of "data_abort_entry" in exception.S. 619 * 620 * In all other cases, these data aborts are considered fatal. 621 */ 622 static int 623 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 624 ksiginfo_t *ksi) 625 { 626 struct pcb *pcb = lwp_getpcb(l); 627 628 #ifdef __XSCALE__ 629 if ((fsr & FAULT_IMPRECISE) != 0 && 630 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 631 /* 632 * Oops, an imprecise, double abort fault. We've lost the 633 * r14_abt/spsr_abt values corresponding to the original 634 * abort, and the spsr saved in the trapframe indicates 635 * ABT mode. 636 */ 637 tf->tf_spsr &= ~PSR_MODE; 638 639 /* 640 * We use a simple heuristic to determine if the double abort 641 * happened as a result of a kernel or user mode access. 642 * If the current trapframe is at the top of the kernel stack, 643 * the fault _must_ have come from user mode. 644 */ 645 if (tf != ((trapframe_t *)pcb->pcb_ksp) - 1) { 646 /* 647 * Kernel mode. We're either about to die a 648 * spectacular death, or pcb_onfault will come 649 * to our rescue. Either way, the current value 650 * of tf->tf_pc is irrelevant. 651 */ 652 tf->tf_spsr |= PSR_SVC32_MODE; 653 if (pcb->pcb_onfault == NULL) 654 printf("\nKernel mode double abort!\n"); 655 } else { 656 /* 657 * User mode. We've lost the program counter at the 658 * time of the fault (not that it was accurate anyway; 659 * it's not called an imprecise fault for nothing). 660 * About all we can do is copy r14_usr to tf_pc and 661 * hope for the best. The process is about to get a 662 * SIGBUS, so it's probably history anyway. 663 */ 664 tf->tf_spsr |= PSR_USR32_MODE; 665 tf->tf_pc = tf->tf_usr_lr; 666 #ifdef THUMB_CODE 667 tf->tf_spsr &= ~PSR_T_bit; 668 if (tf->tf_usr_lr & 1) 669 tf->tf_spsr |= PSR_T_bit; 670 #endif 671 } 672 } 673 674 /* FAR is invalid for imprecise exceptions */ 675 if ((fsr & FAULT_IMPRECISE) != 0) 676 far = 0; 677 #endif /* __XSCALE__ */ 678 679 if (pcb->pcb_onfault) { 680 KDASSERT(TRAP_USERMODE(tf) == 0); 681 tf->tf_r0 = EFAULT; 682 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 683 return (0); 684 } 685 686 /* See if the CPU state needs to be fixed up */ 687 (void) data_abort_fixup(tf, fsr, far, l); 688 689 /* 690 * At this point, if the fault happened in kernel mode, we're toast 691 */ 692 if (!TRAP_USERMODE(tf)) 693 dab_fatal(tf, fsr, far, l, NULL); 694 695 /* Deliver a bus error signal to the process */ 696 KSI_INIT_TRAP(ksi); 697 ksi->ksi_signo = SIGBUS; 698 ksi->ksi_code = BUS_ADRERR; 699 ksi->ksi_addr = (uint32_t *)(intptr_t)far; 700 ksi->ksi_trap = fsr; 701 702 lwp_settrapframe(l, tf); 703 704 return (1); 705 } 706 707 static inline int 708 prefetch_abort_fixup(trapframe_t *tf) 709 { 710 #ifdef CPU_ABORT_FIXUP_REQUIRED 711 int error; 712 713 /* Call the CPU specific prefetch abort fixup routine */ 714 error = cpu_prefetchabt_fixup(tf); 715 if (__predict_true(error != ABORT_FIXUP_FAILED)) 716 return (error); 717 718 /* 719 * Oops, couldn't fix up the instruction 720 */ 721 printf("%s: fixup for %s mode prefetch abort failed.\n", __func__, 722 TRAP_USERMODE(tf) ? "user" : "kernel"); 723 #ifdef THUMB_CODE 724 if (tf->tf_spsr & PSR_T_bit) { 725 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 726 tf->tf_pc, *((uint16 *)(tf->tf_pc & ~1)), 727 *((uint16 *)((tf->tf_pc + 2) & ~1))); 728 } 729 else 730 #endif 731 { 732 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 733 *((u_int *)tf->tf_pc)); 734 } 735 disassemble(tf->tf_pc); 736 737 /* Die now if this happened in kernel mode */ 738 if (!TRAP_USERMODE(tf)) 739 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 740 741 return (error); 742 #else 743 return (ABORT_FIXUP_OK); 744 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 745 } 746 747 /* 748 * void prefetch_abort_handler(trapframe_t *tf) 749 * 750 * Abort handler called when instruction execution occurs at 751 * a non existent or restricted (access permissions) memory page. 752 * If the address is invalid and we were in SVC mode then panic as 753 * the kernel should never prefetch abort. 754 * If the address is invalid and the page is mapped then the user process 755 * does no have read permission so send it a signal. 756 * Otherwise fault the page in and try again. 757 */ 758 void 759 prefetch_abort_handler(trapframe_t *tf) 760 { 761 struct lwp *l; 762 struct pcb *pcb; 763 struct vm_map *map; 764 vaddr_t fault_pc, va; 765 ksiginfo_t ksi; 766 int error, user; 767 768 UVMHIST_FUNC("prefetch_abort_handler"); UVMHIST_CALLED(maphist); 769 770 /* Update vmmeter statistics */ 771 curcpu()->ci_data.cpu_ntrap++; 772 773 l = curlwp; 774 pcb = lwp_getpcb(l); 775 776 if ((user = TRAP_USERMODE(tf)) != 0) 777 LWP_CACHE_CREDS(l, l->l_proc); 778 779 /* 780 * Enable IRQ's (disabled by the abort) This always comes 781 * from user mode so we know interrupts were not disabled. 782 * But we check anyway. 783 */ 784 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 785 if (__predict_true((tf->tf_spsr & I32_bit) != IF32_bits)) 786 restore_interrupts(tf->tf_spsr & IF32_bits); 787 788 /* See if the CPU state needs to be fixed up */ 789 switch (prefetch_abort_fixup(tf)) { 790 case ABORT_FIXUP_RETURN: 791 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 792 return; 793 case ABORT_FIXUP_FAILED: 794 /* Deliver a SIGILL to the process */ 795 KSI_INIT_TRAP(&ksi); 796 ksi.ksi_signo = SIGILL; 797 ksi.ksi_code = ILL_ILLOPC; 798 ksi.ksi_addr = (uint32_t *)(intptr_t) tf->tf_pc; 799 lwp_settrapframe(l, tf); 800 goto do_trapsignal; 801 default: 802 break; 803 } 804 805 /* Prefetch aborts cannot happen in kernel mode */ 806 if (__predict_false(!user)) 807 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 808 809 /* Get fault address */ 810 fault_pc = tf->tf_pc; 811 lwp_settrapframe(l, tf); 812 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, tf=0x%x)", fault_pc, l, tf, 813 0); 814 815 /* Ok validate the address, can only execute in USER space */ 816 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 817 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 818 KSI_INIT_TRAP(&ksi); 819 ksi.ksi_signo = SIGSEGV; 820 ksi.ksi_code = SEGV_ACCERR; 821 ksi.ksi_addr = (uint32_t *)(intptr_t) fault_pc; 822 ksi.ksi_trap = fault_pc; 823 goto do_trapsignal; 824 } 825 826 map = &l->l_proc->p_vmspace->vm_map; 827 va = trunc_page(fault_pc); 828 829 /* 830 * See if the pmap can handle this fault on its own... 831 */ 832 #ifdef DEBUG 833 last_fault_code = -1; 834 #endif 835 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ|VM_PROT_EXECUTE, 1)) { 836 UVMHIST_LOG (maphist, " <- emulated", 0, 0, 0, 0); 837 goto out; 838 } 839 840 #ifdef DIAGNOSTIC 841 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 842 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 843 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 844 } 845 #endif 846 847 KASSERT(pcb->pcb_onfault == NULL); 848 error = uvm_fault(map, va, VM_PROT_READ); 849 850 if (__predict_true(error == 0)) { 851 UVMHIST_LOG (maphist, " <- uvm", 0, 0, 0, 0); 852 goto out; 853 } 854 KSI_INIT_TRAP(&ksi); 855 856 UVMHIST_LOG (maphist, " <- fatal (%d)", error, 0, 0, 0); 857 if (error == ENOMEM) { 858 printf("UVM: pid %d (%s), uid %d killed: " 859 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 860 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 861 ksi.ksi_signo = SIGKILL; 862 } else 863 ksi.ksi_signo = SIGSEGV; 864 865 ksi.ksi_code = SEGV_MAPERR; 866 ksi.ksi_addr = (uint32_t *)(intptr_t) fault_pc; 867 ksi.ksi_trap = fault_pc; 868 869 do_trapsignal: 870 call_trapsignal(l, &ksi); 871 872 out: 873 KASSERT(!TRAP_USERMODE(tf) || (tf->tf_spsr & IF32_bits) == 0); 874 userret(l); 875 } 876 877 /* 878 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 879 * If the read succeeds, the value is written to 'rptr' and zero is returned. 880 * Else, return EFAULT. 881 */ 882 int 883 badaddr_read(void *addr, size_t size, void *rptr) 884 { 885 extern int badaddr_read_1(const uint8_t *, uint8_t *); 886 extern int badaddr_read_2(const uint16_t *, uint16_t *); 887 extern int badaddr_read_4(const uint32_t *, uint32_t *); 888 union { 889 uint8_t v1; 890 uint16_t v2; 891 uint32_t v4; 892 } u; 893 int rv, s; 894 895 cpu_drain_writebuf(); 896 897 s = splhigh(); 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 panic("%s: invalid size (%zu)", __func__, size); 921 } 922 923 splx(s); 924 925 /* Return EFAULT if the address was invalid, else zero */ 926 return (rv); 927 } 928