1 /* $NetBSD: fault.c,v 1.49 2004/03/14 01:08:47 cl 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 1.49 2004/03/14 01:08:47 cl Exp $"); 85 86 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/proc.h> 89 #include <sys/savar.h> 90 #include <sys/user.h> 91 #include <sys/kernel.h> 92 93 #include <uvm/uvm_extern.h> 94 95 #include <arm/cpuconf.h> 96 97 #include <machine/frame.h> 98 #include <arm/arm32/katelib.h> 99 #include <machine/cpu.h> 100 #include <machine/intr.h> 101 #if defined(DDB) || defined(KGDB) 102 #include <machine/db_machdep.h> 103 #ifdef KGDB 104 #include <sys/kgdb.h> 105 #endif 106 #if !defined(DDB) 107 #define kdb_trap kgdb_trap 108 #endif 109 #endif 110 111 #include <arch/arm/arm/disassem.h> 112 #include <arm/arm32/machdep.h> 113 114 extern char fusubailout[]; 115 116 #ifdef DEBUG 117 int last_fault_code; /* For the benefit of pmap_fault_fixup() */ 118 #endif 119 120 #if defined(CPU_ARM3) || defined(CPU_ARM6) || \ 121 defined(CPU_ARM7) || defined(CPU_ARM7TDMI) 122 /* These CPUs may need data/prefetch abort fixups */ 123 #define CPU_ABORT_FIXUP_REQUIRED 124 #endif 125 126 struct data_abort { 127 int (*func)(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 128 const char *desc; 129 }; 130 131 static int dab_fatal(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 132 static int dab_align(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 133 static int dab_buserr(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 134 135 static const struct data_abort data_aborts[] = { 136 {dab_fatal, "Vector Exception"}, 137 {dab_align, "Alignment Fault 1"}, 138 {dab_fatal, "Terminal Exception"}, 139 {dab_align, "Alignment Fault 3"}, 140 {dab_buserr, "External Linefetch Abort (S)"}, 141 {NULL, "Translation Fault (S)"}, 142 {dab_buserr, "External Linefetch Abort (P)"}, 143 {NULL, "Translation Fault (P)"}, 144 {dab_buserr, "External Non-Linefetch Abort (S)"}, 145 {NULL, "Domain Fault (S)"}, 146 {dab_buserr, "External Non-Linefetch Abort (P)"}, 147 {NULL, "Domain Fault (P)"}, 148 {dab_buserr, "External Translation Abort (L1)"}, 149 {NULL, "Permission Fault (S)"}, 150 {dab_buserr, "External Translation Abort (L2)"}, 151 {NULL, "Permission Fault (P)"} 152 }; 153 154 /* Determine if a fault came from user mode */ 155 #define TRAP_USERMODE(tf) ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE) 156 157 /* Determine if 'x' is a permission fault */ 158 #define IS_PERMISSION_FAULT(x) \ 159 (((1 << ((x) & FAULT_TYPE_MASK)) & \ 160 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) 161 162 #if 0 163 /* maybe one day we'll do emulations */ 164 #define TRAPSIGNAL(l,k) (*(l)->l_proc->p_emul->e_trapsignal)((l), (k)) 165 #else 166 #define TRAPSIGNAL(l,k) trapsignal((l), (k)) 167 #endif 168 169 static __inline void 170 call_trapsignal(struct lwp *l, ksiginfo_t *ksi) 171 { 172 173 KERNEL_PROC_LOCK(l->l_proc); 174 TRAPSIGNAL(l, ksi); 175 KERNEL_PROC_UNLOCK(l->l_proc); 176 } 177 178 static __inline int 179 data_abort_fixup(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l) 180 { 181 #ifdef CPU_ABORT_FIXUP_REQUIRED 182 int error; 183 184 /* Call the CPU specific data abort fixup routine */ 185 error = cpu_dataabt_fixup(tf); 186 if (__predict_true(error != ABORT_FIXUP_FAILED)) 187 return (error); 188 189 /* 190 * Oops, couldn't fix up the instruction 191 */ 192 printf("data_abort_fixup: fixup for %s mode data abort failed.\n", 193 TRAP_USERMODE(tf) ? "user" : "kernel"); 194 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 195 *((u_int *)tf->tf_pc)); 196 disassemble(tf->tf_pc); 197 198 /* Die now if this happened in kernel mode */ 199 if (!TRAP_USERMODE(tf)) 200 dab_fatal(tf, fsr, far, l, NULL); 201 202 return (error); 203 #else 204 return (ABORT_FIXUP_OK); 205 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 206 } 207 208 void 209 data_abort_handler(trapframe_t *tf) 210 { 211 struct vm_map *map; 212 struct pcb *pcb; 213 struct lwp *l; 214 u_int user, far, fsr; 215 vm_prot_t ftype; 216 void *onfault; 217 vaddr_t va; 218 int error; 219 ksiginfo_t ksi; 220 221 /* Grab FAR/FSR before enabling interrupts */ 222 far = cpu_faultaddress(); 223 fsr = cpu_faultstatus(); 224 225 /* Update vmmeter statistics */ 226 uvmexp.traps++; 227 228 /* Re-enable interrupts if they were enabled previously */ 229 if (__predict_true((tf->tf_spsr & I32_bit) == 0)) 230 enable_interrupts(I32_bit); 231 232 /* Get the current lwp structure or lwp0 if there is none */ 233 l = (curlwp != NULL) ? curlwp : &lwp0; 234 235 /* Data abort came from user mode? */ 236 user = TRAP_USERMODE(tf); 237 238 /* Grab the current pcb */ 239 pcb = &l->l_addr->u_pcb; 240 241 /* Invoke the appropriate handler, if necessary */ 242 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 243 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, 244 l, &ksi)) 245 goto do_trapsignal; 246 goto out; 247 } 248 249 /* 250 * At this point, we're dealing with one of the following data aborts: 251 * 252 * FAULT_TRANS_S - Translation -- Section 253 * FAULT_TRANS_P - Translation -- Page 254 * FAULT_DOMAIN_S - Domain -- Section 255 * FAULT_DOMAIN_P - Domain -- Page 256 * FAULT_PERM_S - Permission -- Section 257 * FAULT_PERM_P - Permission -- Page 258 * 259 * These are the main virtual memory-related faults signalled by 260 * the MMU. 261 */ 262 263 /* fusubailout is used by [fs]uswintr to avoid page faulting */ 264 if (__predict_false(pcb->pcb_onfault == fusubailout)) { 265 tf->tf_r0 = EFAULT; 266 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 267 return; 268 } 269 270 if (user) 271 l->l_addr->u_pcb.pcb_tf = tf; 272 273 /* 274 * Make sure the Program Counter is sane. We could fall foul of 275 * someone executing Thumb code, in which case the PC might not 276 * be word-aligned. This would cause a kernel alignment fault 277 * further down if we have to decode the current instruction. 278 * XXX: It would be nice to be able to support Thumb at some point. 279 */ 280 if (__predict_false((tf->tf_pc & 3) != 0)) { 281 if (user) { 282 /* 283 * Give the user an illegal instruction signal. 284 */ 285 /* Deliver a SIGILL to the process */ 286 KSI_INIT_TRAP(&ksi); 287 ksi.ksi_signo = SIGILL; 288 ksi.ksi_code = ILL_ILLOPC; 289 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 290 ksi.ksi_trap = fsr; 291 goto do_trapsignal; 292 } 293 294 /* 295 * The kernel never executes Thumb code. 296 */ 297 printf("\ndata_abort_fault: Misaligned Kernel-mode " 298 "Program Counter\n"); 299 dab_fatal(tf, fsr, far, l, NULL); 300 } 301 302 /* See if the CPU state needs to be fixed up */ 303 switch (data_abort_fixup(tf, fsr, far, l)) { 304 case ABORT_FIXUP_RETURN: 305 return; 306 case ABORT_FIXUP_FAILED: 307 /* Deliver a SIGILL to the process */ 308 KSI_INIT_TRAP(&ksi); 309 ksi.ksi_signo = SIGILL; 310 ksi.ksi_code = ILL_ILLOPC; 311 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 312 ksi.ksi_trap = fsr; 313 goto do_trapsignal; 314 default: 315 break; 316 } 317 318 va = trunc_page((vaddr_t)far); 319 320 /* 321 * It is only a kernel address space fault iff: 322 * 1. user == 0 and 323 * 2. pcb_onfault not set or 324 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. 325 */ 326 if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS || 327 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && 328 __predict_true((pcb->pcb_onfault == NULL || 329 (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) { 330 map = kernel_map; 331 332 /* Was the fault due to the FPE/IPKDB ? */ 333 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { 334 KSI_INIT_TRAP(&ksi); 335 ksi.ksi_signo = SIGSEGV; 336 ksi.ksi_code = SEGV_ACCERR; 337 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 338 ksi.ksi_trap = fsr; 339 340 /* 341 * Force exit via userret() 342 * This is necessary as the FPE is an extension to 343 * userland that actually runs in a priveledged mode 344 * but uses USR mode permissions for its accesses. 345 */ 346 user = 1; 347 goto do_trapsignal; 348 } 349 } else { 350 map = &l->l_proc->p_vmspace->vm_map; 351 if (l->l_flag & L_SA) { 352 l->l_savp->savp_faultaddr = (vaddr_t)far; 353 l->l_flag |= L_SA_PAGEFAULT; 354 } 355 } 356 357 /* 358 * We need to know whether the page should be mapped 359 * as R or R/W. The MMU does not give us the info as 360 * to whether the fault was caused by a read or a write. 361 * 362 * However, we know that a permission fault can only be 363 * the result of a write to a read-only location, so 364 * we can deal with those quickly. 365 * 366 * Otherwise we need to disassemble the instruction 367 * responsible to determine if it was a write. 368 */ 369 if (IS_PERMISSION_FAULT(fsr)) 370 ftype = VM_PROT_WRITE; 371 else { 372 u_int insn = ReadWord(tf->tf_pc); 373 374 if (((insn & 0x0c100000) == 0x04000000) || /* STR/STRB */ 375 ((insn & 0x0e1000b0) == 0x000000b0) || /* STRH/STRD */ 376 ((insn & 0x0a100000) == 0x08000000)) /* STM/CDT */ 377 ftype = VM_PROT_WRITE; 378 else 379 if ((insn & 0x0fb00ff0) == 0x01000090) /* SWP */ 380 ftype = VM_PROT_READ | VM_PROT_WRITE; 381 else 382 ftype = VM_PROT_READ; 383 } 384 385 /* 386 * See if the fault is as a result of ref/mod emulation, 387 * or domain mismatch. 388 */ 389 #ifdef DEBUG 390 last_fault_code = fsr; 391 #endif 392 if (pmap_fault_fixup(map->pmap, va, ftype, user)) { 393 if (map != kernel_map) 394 l->l_flag &= ~L_SA_PAGEFAULT; 395 goto out; 396 } 397 398 if (__predict_false(current_intr_depth > 0)) { 399 if (pcb->pcb_onfault) { 400 tf->tf_r0 = EINVAL; 401 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 402 return; 403 } 404 printf("\nNon-emulated page fault with intr_depth > 0\n"); 405 dab_fatal(tf, fsr, far, l, NULL); 406 } 407 408 onfault = pcb->pcb_onfault; 409 pcb->pcb_onfault = NULL; 410 error = uvm_fault(map, va, 0, ftype); 411 pcb->pcb_onfault = onfault; 412 413 if (map != kernel_map) 414 l->l_flag &= ~L_SA_PAGEFAULT; 415 416 if (__predict_true(error == 0)) { 417 if (user) 418 uvm_grow(l->l_proc, va); /* Record any stack growth */ 419 goto out; 420 } 421 422 if (user == 0) { 423 if (pcb->pcb_onfault) { 424 tf->tf_r0 = error; 425 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 426 return; 427 } 428 429 printf("\nuvm_fault(%p, %lx, %x, 0) -> %x\n", map, va, ftype, 430 error); 431 dab_fatal(tf, fsr, far, l, NULL); 432 } 433 434 KSI_INIT_TRAP(&ksi); 435 436 if (error == ENOMEM) { 437 printf("UVM: pid %d (%s), uid %d killed: " 438 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 439 (l->l_proc->p_cred && l->l_proc->p_ucred) ? 440 l->l_proc->p_ucred->cr_uid : -1); 441 ksi.ksi_signo = SIGKILL; 442 } else 443 ksi.ksi_signo = SIGSEGV; 444 445 ksi.ksi_code = (error == EACCES) ? SEGV_ACCERR : SEGV_MAPERR; 446 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 447 ksi.ksi_trap = fsr; 448 449 do_trapsignal: 450 call_trapsignal(l, &ksi); 451 out: 452 /* If returning to user mode, make sure to invoke userret() */ 453 if (user) 454 userret(l); 455 } 456 457 /* 458 * dab_fatal() handles the following data aborts: 459 * 460 * FAULT_WRTBUF_0 - Vector Exception 461 * FAULT_WRTBUF_1 - Terminal Exception 462 * 463 * We should never see these on a properly functioning system. 464 * 465 * This function is also called by the other handlers if they 466 * detect a fatal problem. 467 * 468 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 469 */ 470 static int 471 dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 472 { 473 const char *mode; 474 475 mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 476 477 if (l != NULL) { 478 printf("Fatal %s mode data abort: '%s'\n", mode, 479 data_aborts[fsr & FAULT_TYPE_MASK].desc); 480 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 481 if ((fsr & FAULT_IMPRECISE) == 0) 482 printf("%08x, ", far); 483 else 484 printf("Invalid, "); 485 printf("spsr=%08x\n", tf->tf_spsr); 486 } else { 487 printf("Fatal %s mode prefetch abort at 0x%08x\n", 488 mode, tf->tf_pc); 489 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 490 } 491 492 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 493 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 494 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 495 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 496 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 497 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 498 printf("r12=%08x, ", tf->tf_r12); 499 500 if (TRAP_USERMODE(tf)) 501 printf("usp=%08x, ulr=%08x", 502 tf->tf_usr_sp, tf->tf_usr_lr); 503 else 504 printf("ssp=%08x, slr=%08x", 505 tf->tf_svc_sp, tf->tf_svc_lr); 506 printf(", pc =%08x\n\n", tf->tf_pc); 507 508 #if defined(DDB) || defined(KGDB) 509 kdb_trap(T_FAULT, tf); 510 #endif 511 panic("Fatal abort"); 512 /*NOTREACHED*/ 513 } 514 515 /* 516 * dab_align() handles the following data aborts: 517 * 518 * FAULT_ALIGN_0 - Alignment fault 519 * FAULT_ALIGN_0 - Alignment fault 520 * 521 * These faults are fatal if they happen in kernel mode. Otherwise, we 522 * deliver a bus error to the process. 523 */ 524 static int 525 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 526 { 527 528 /* Alignment faults are always fatal if they occur in kernel mode */ 529 if (!TRAP_USERMODE(tf)) 530 dab_fatal(tf, fsr, far, l, NULL); 531 532 /* pcb_onfault *must* be NULL at this point */ 533 KDASSERT(l->l_addr->u_pcb.pcb_onfault == NULL); 534 535 /* See if the CPU state needs to be fixed up */ 536 (void) data_abort_fixup(tf, fsr, far, l); 537 538 /* Deliver a bus error signal to the process */ 539 KSI_INIT_TRAP(ksi); 540 ksi->ksi_signo = SIGBUS; 541 ksi->ksi_code = BUS_ADRALN; 542 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 543 ksi->ksi_trap = fsr; 544 545 l->l_addr->u_pcb.pcb_tf = tf; 546 547 return (1); 548 } 549 550 /* 551 * dab_buserr() handles the following data aborts: 552 * 553 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 554 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 555 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 556 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 557 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 558 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 559 * 560 * If pcb_onfault is set, flag the fault and return to the handler. 561 * If the fault occurred in user mode, give the process a SIGBUS. 562 * 563 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 564 * can be flagged as imprecise in the FSR. This causes a real headache 565 * since some of the machine state is lost. In this case, tf->tf_pc 566 * may not actually point to the offending instruction. In fact, if 567 * we've taken a double abort fault, it generally points somewhere near 568 * the top of "data_abort_entry" in exception.S. 569 * 570 * In all other cases, these data aborts are considered fatal. 571 */ 572 static int 573 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 574 ksiginfo_t *ksi) 575 { 576 struct pcb *pcb = &l->l_addr->u_pcb; 577 578 #ifdef __XSCALE__ 579 if ((fsr & FAULT_IMPRECISE) != 0 && 580 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 581 /* 582 * Oops, an imprecise, double abort fault. We've lost the 583 * r14_abt/spsr_abt values corresponding to the original 584 * abort, and the spsr saved in the trapframe indicates 585 * ABT mode. 586 */ 587 tf->tf_spsr &= ~PSR_MODE; 588 589 /* 590 * We use a simple heuristic to determine if the double abort 591 * happened as a result of a kernel or user mode access. 592 * If the current trapframe is at the top of the kernel stack, 593 * the fault _must_ have come from user mode. 594 */ 595 if (tf != ((trapframe_t *)pcb->pcb_un.un_32.pcb32_sp) - 1) { 596 /* 597 * Kernel mode. We're either about to die a 598 * spectacular death, or pcb_onfault will come 599 * to our rescue. Either way, the current value 600 * of tf->tf_pc is irrelevant. 601 */ 602 tf->tf_spsr |= PSR_SVC32_MODE; 603 if (pcb->pcb_onfault == NULL) 604 printf("\nKernel mode double abort!\n"); 605 } else { 606 /* 607 * User mode. We've lost the program counter at the 608 * time of the fault (not that it was accurate anyway; 609 * it's not called an imprecise fault for nothing). 610 * About all we can do is copy r14_usr to tf_pc and 611 * hope for the best. The process is about to get a 612 * SIGBUS, so it's probably history anyway. 613 */ 614 tf->tf_spsr |= PSR_USR32_MODE; 615 tf->tf_pc = tf->tf_usr_lr; 616 } 617 } 618 619 /* FAR is invalid for imprecise exceptions */ 620 if ((fsr & FAULT_IMPRECISE) != 0) 621 far = 0; 622 #endif /* __XSCALE__ */ 623 624 if (pcb->pcb_onfault) { 625 KDASSERT(TRAP_USERMODE(tf) == 0); 626 tf->tf_r0 = EFAULT; 627 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 628 return (0); 629 } 630 631 /* See if the CPU state needs to be fixed up */ 632 (void) data_abort_fixup(tf, fsr, far, l); 633 634 /* 635 * At this point, if the fault happened in kernel mode, we're toast 636 */ 637 if (!TRAP_USERMODE(tf)) 638 dab_fatal(tf, fsr, far, l, NULL); 639 640 /* Deliver a bus error signal to the process */ 641 KSI_INIT_TRAP(ksi); 642 ksi->ksi_signo = SIGBUS; 643 ksi->ksi_code = BUS_ADRERR; 644 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 645 ksi->ksi_trap = fsr; 646 647 l->l_addr->u_pcb.pcb_tf = tf; 648 649 return (1); 650 } 651 652 static __inline int 653 prefetch_abort_fixup(trapframe_t *tf) 654 { 655 #ifdef CPU_ABORT_FIXUP_REQUIRED 656 int error; 657 658 /* Call the CPU specific prefetch abort fixup routine */ 659 error = cpu_prefetchabt_fixup(tf); 660 if (__predict_true(error != ABORT_FIXUP_FAILED)) 661 return (error); 662 663 /* 664 * Oops, couldn't fix up the instruction 665 */ 666 printf( 667 "prefetch_abort_fixup: fixup for %s mode prefetch abort failed.\n", 668 TRAP_USERMODE(tf) ? "user" : "kernel"); 669 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 670 *((u_int *)tf->tf_pc)); 671 disassemble(tf->tf_pc); 672 673 /* Die now if this happened in kernel mode */ 674 if (!TRAP_USERMODE(tf)) 675 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 676 677 return (error); 678 #else 679 return (ABORT_FIXUP_OK); 680 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 681 } 682 683 /* 684 * void prefetch_abort_handler(trapframe_t *tf) 685 * 686 * Abort handler called when instruction execution occurs at 687 * a non existent or restricted (access permissions) memory page. 688 * If the address is invalid and we were in SVC mode then panic as 689 * the kernel should never prefetch abort. 690 * If the address is invalid and the page is mapped then the user process 691 * does no have read permission so send it a signal. 692 * Otherwise fault the page in and try again. 693 */ 694 void 695 prefetch_abort_handler(trapframe_t *tf) 696 { 697 struct lwp *l; 698 struct vm_map *map; 699 vaddr_t fault_pc, va; 700 ksiginfo_t ksi; 701 int error; 702 703 /* Update vmmeter statistics */ 704 uvmexp.traps++; 705 706 /* 707 * Enable IRQ's (disabled by the abort) This always comes 708 * from user mode so we know interrupts were not disabled. 709 * But we check anyway. 710 */ 711 if (__predict_true((tf->tf_spsr & I32_bit) == 0)) 712 enable_interrupts(I32_bit); 713 714 /* See if the CPU state needs to be fixed up */ 715 switch (prefetch_abort_fixup(tf)) { 716 case ABORT_FIXUP_RETURN: 717 return; 718 case ABORT_FIXUP_FAILED: 719 /* Deliver a SIGILL to the process */ 720 KSI_INIT_TRAP(&ksi); 721 ksi.ksi_signo = SIGILL; 722 ksi.ksi_code = ILL_ILLOPC; 723 ksi.ksi_addr = (u_int32_t *)(intptr_t) tf->tf_pc; 724 l = curlwp; 725 l->l_addr->u_pcb.pcb_tf = tf; 726 goto do_trapsignal; 727 default: 728 break; 729 } 730 731 /* Prefetch aborts cannot happen in kernel mode */ 732 if (__predict_false(!TRAP_USERMODE(tf))) 733 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 734 735 /* Get fault address */ 736 fault_pc = tf->tf_pc; 737 l = curlwp; 738 l->l_addr->u_pcb.pcb_tf = tf; 739 740 /* Ok validate the address, can only execute in USER space */ 741 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 742 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 743 KSI_INIT_TRAP(&ksi); 744 ksi.ksi_signo = SIGSEGV; 745 ksi.ksi_code = SEGV_ACCERR; 746 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 747 ksi.ksi_trap = fault_pc; 748 goto do_trapsignal; 749 } 750 751 map = &l->l_proc->p_vmspace->vm_map; 752 va = trunc_page(fault_pc); 753 754 /* 755 * See if the pmap can handle this fault on its own... 756 */ 757 #ifdef DEBUG 758 last_fault_code = -1; 759 #endif 760 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1)) 761 goto out; 762 763 #ifdef DIAGNOSTIC 764 if (__predict_false(current_intr_depth > 0)) { 765 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 766 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 767 } 768 #endif 769 770 error = uvm_fault(map, va, 0, VM_PROT_READ); 771 if (__predict_true(error == 0)) 772 goto out; 773 774 KSI_INIT_TRAP(&ksi); 775 776 if (error == ENOMEM) { 777 printf("UVM: pid %d (%s), uid %d killed: " 778 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 779 (l->l_proc->p_cred && l->l_proc->p_ucred) ? 780 l->l_proc->p_ucred->cr_uid : -1); 781 ksi.ksi_signo = SIGKILL; 782 } else 783 ksi.ksi_signo = SIGSEGV; 784 785 ksi.ksi_code = SEGV_MAPERR; 786 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 787 ksi.ksi_trap = fault_pc; 788 789 do_trapsignal: 790 call_trapsignal(l, &ksi); 791 792 out: 793 userret(l); 794 } 795 796 /* 797 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 798 * If the read succeeds, the value is written to 'rptr' and zero is returned. 799 * Else, return EFAULT. 800 */ 801 int 802 badaddr_read(void *addr, size_t size, void *rptr) 803 { 804 extern int badaddr_read_1(const uint8_t *, uint8_t *); 805 extern int badaddr_read_2(const uint16_t *, uint16_t *); 806 extern int badaddr_read_4(const uint32_t *, uint32_t *); 807 union { 808 uint8_t v1; 809 uint16_t v2; 810 uint32_t v4; 811 } u; 812 struct pcb *curpcb_save; 813 int rv, s; 814 815 cpu_drain_writebuf(); 816 817 /* 818 * We might be called at interrupt time, so arrange to steal 819 * lwp0's PCB temporarily, if required, so that pcb_onfault 820 * handling works correctly. 821 */ 822 s = splhigh(); 823 if ((curpcb_save = curpcb) == NULL) 824 curpcb = &lwp0.l_addr->u_pcb; 825 826 /* Read from the test address. */ 827 switch (size) { 828 case sizeof(uint8_t): 829 rv = badaddr_read_1(addr, &u.v1); 830 if (rv == 0 && rptr) 831 *(uint8_t *) rptr = u.v1; 832 break; 833 834 case sizeof(uint16_t): 835 rv = badaddr_read_2(addr, &u.v2); 836 if (rv == 0 && rptr) 837 *(uint16_t *) rptr = u.v2; 838 break; 839 840 case sizeof(uint32_t): 841 rv = badaddr_read_4(addr, &u.v4); 842 if (rv == 0 && rptr) 843 *(uint32_t *) rptr = u.v4; 844 break; 845 846 default: 847 curpcb = curpcb_save; 848 panic("badaddr: invalid size (%lu)", (u_long) size); 849 } 850 851 /* Restore curpcb */ 852 curpcb = curpcb_save; 853 splx(s); 854 855 /* Return EFAULT if the address was invalid, else zero */ 856 return (rv); 857 } 858