fault.c revision 1.59
1 /* $NetBSD: fault.c,v 1.59 2006/05/14 21:55:09 elad 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 1.59 2006/05/14 21:55:09 elad 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 #include <uvm/uvm_stat.h> 95 #ifdef UVMHIST 96 #include <uvm/uvm.h> 97 #endif 98 99 #include <arm/cpuconf.h> 100 101 #include <machine/frame.h> 102 #include <arm/arm32/katelib.h> 103 #include <machine/cpu.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_PROC_LOCK(l); 178 TRAPSIGNAL(l, ksi); 179 KERNEL_PROC_UNLOCK(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 or lwp0 if there is none */ 250 l = (curlwp != NULL) ? curlwp : &lwp0; 251 252 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, far=0x%x, fsr=0x%x)", 253 tf->tf_pc, l, far, fsr); 254 255 /* Data abort came from user mode? */ 256 user = TRAP_USERMODE(tf); 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 if (l->l_flag & L_SA) { 383 l->l_savp->savp_faultaddr = (vaddr_t)far; 384 l->l_flag |= L_SA_PAGEFAULT; 385 } 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 ftype = VM_PROT_WRITE; 431 else if ((insn & 0x0fb00ff0) == 0x01000090)/* SWP */ 432 ftype = VM_PROT_READ | VM_PROT_WRITE; 433 else 434 ftype = VM_PROT_READ; 435 } 436 } 437 438 /* 439 * See if the fault is as a result of ref/mod emulation, 440 * or domain mismatch. 441 */ 442 #ifdef DEBUG 443 last_fault_code = fsr; 444 #endif 445 if (pmap_fault_fixup(map->pmap, va, ftype, user)) { 446 if (map != kernel_map) 447 l->l_flag &= ~L_SA_PAGEFAULT; 448 UVMHIST_LOG(maphist, " <- ref/mod emul", 0, 0, 0, 0); 449 goto out; 450 } 451 452 if (__predict_false(current_intr_depth > 0)) { 453 if (pcb->pcb_onfault) { 454 tf->tf_r0 = EINVAL; 455 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 456 return; 457 } 458 printf("\nNon-emulated page fault with intr_depth > 0\n"); 459 dab_fatal(tf, fsr, far, l, NULL); 460 } 461 462 onfault = pcb->pcb_onfault; 463 pcb->pcb_onfault = NULL; 464 error = uvm_fault(map, va, ftype); 465 pcb->pcb_onfault = onfault; 466 467 if (map != kernel_map) 468 l->l_flag &= ~L_SA_PAGEFAULT; 469 470 if (__predict_true(error == 0)) { 471 if (user) 472 uvm_grow(l->l_proc, va); /* Record any stack growth */ 473 UVMHIST_LOG(maphist, " <- uvm", 0, 0, 0, 0); 474 goto out; 475 } 476 477 if (user == 0) { 478 if (pcb->pcb_onfault) { 479 tf->tf_r0 = error; 480 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 481 return; 482 } 483 484 printf("\nuvm_fault(%p, %lx, %x) -> %x\n", map, va, ftype, 485 error); 486 dab_fatal(tf, fsr, far, l, NULL); 487 } 488 489 KSI_INIT_TRAP(&ksi); 490 491 if (error == ENOMEM) { 492 printf("UVM: pid %d (%s), uid %d killed: " 493 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 494 l->l_proc->p_cred ? kauth_cred_geteuid(l->l_proc->p_cred) : -1); 495 ksi.ksi_signo = SIGKILL; 496 } else 497 ksi.ksi_signo = SIGSEGV; 498 499 ksi.ksi_code = (error == EACCES) ? SEGV_ACCERR : SEGV_MAPERR; 500 ksi.ksi_addr = (u_int32_t *)(intptr_t) far; 501 ksi.ksi_trap = fsr; 502 UVMHIST_LOG(maphist, " <- erorr (%d)", error, 0, 0, 0); 503 504 do_trapsignal: 505 call_trapsignal(l, &ksi); 506 out: 507 /* If returning to user mode, make sure to invoke userret() */ 508 if (user) 509 userret(l); 510 } 511 512 /* 513 * dab_fatal() handles the following data aborts: 514 * 515 * FAULT_WRTBUF_0 - Vector Exception 516 * FAULT_WRTBUF_1 - Terminal Exception 517 * 518 * We should never see these on a properly functioning system. 519 * 520 * This function is also called by the other handlers if they 521 * detect a fatal problem. 522 * 523 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 524 */ 525 static int 526 dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 527 { 528 const char *mode; 529 530 mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 531 532 if (l != NULL) { 533 printf("Fatal %s mode data abort: '%s'\n", mode, 534 data_aborts[fsr & FAULT_TYPE_MASK].desc); 535 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 536 if ((fsr & FAULT_IMPRECISE) == 0) 537 printf("%08x, ", far); 538 else 539 printf("Invalid, "); 540 printf("spsr=%08x\n", tf->tf_spsr); 541 } else { 542 printf("Fatal %s mode prefetch abort at 0x%08x\n", 543 mode, tf->tf_pc); 544 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 545 } 546 547 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 548 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 549 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 550 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 551 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 552 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 553 printf("r12=%08x, ", tf->tf_r12); 554 555 if (TRAP_USERMODE(tf)) 556 printf("usp=%08x, ulr=%08x", 557 tf->tf_usr_sp, tf->tf_usr_lr); 558 else 559 printf("ssp=%08x, slr=%08x", 560 tf->tf_svc_sp, tf->tf_svc_lr); 561 printf(", pc =%08x\n\n", tf->tf_pc); 562 563 #if defined(DDB) || defined(KGDB) 564 kdb_trap(T_FAULT, tf); 565 #endif 566 panic("Fatal abort"); 567 /*NOTREACHED*/ 568 } 569 570 /* 571 * dab_align() handles the following data aborts: 572 * 573 * FAULT_ALIGN_0 - Alignment fault 574 * FAULT_ALIGN_0 - Alignment fault 575 * 576 * These faults are fatal if they happen in kernel mode. Otherwise, we 577 * deliver a bus error to the process. 578 */ 579 static int 580 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 581 { 582 583 /* Alignment faults are always fatal if they occur in kernel mode */ 584 if (!TRAP_USERMODE(tf)) 585 dab_fatal(tf, fsr, far, l, NULL); 586 587 /* pcb_onfault *must* be NULL at this point */ 588 KDASSERT(l->l_addr->u_pcb.pcb_onfault == NULL); 589 590 /* See if the CPU state needs to be fixed up */ 591 (void) data_abort_fixup(tf, fsr, far, l); 592 593 /* Deliver a bus error signal to the process */ 594 KSI_INIT_TRAP(ksi); 595 ksi->ksi_signo = SIGBUS; 596 ksi->ksi_code = BUS_ADRALN; 597 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 598 ksi->ksi_trap = fsr; 599 600 l->l_addr->u_pcb.pcb_tf = tf; 601 602 return (1); 603 } 604 605 /* 606 * dab_buserr() handles the following data aborts: 607 * 608 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 609 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 610 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 611 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 612 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 613 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 614 * 615 * If pcb_onfault is set, flag the fault and return to the handler. 616 * If the fault occurred in user mode, give the process a SIGBUS. 617 * 618 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 619 * can be flagged as imprecise in the FSR. This causes a real headache 620 * since some of the machine state is lost. In this case, tf->tf_pc 621 * may not actually point to the offending instruction. In fact, if 622 * we've taken a double abort fault, it generally points somewhere near 623 * the top of "data_abort_entry" in exception.S. 624 * 625 * In all other cases, these data aborts are considered fatal. 626 */ 627 static int 628 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 629 ksiginfo_t *ksi) 630 { 631 struct pcb *pcb = &l->l_addr->u_pcb; 632 633 #ifdef __XSCALE__ 634 if ((fsr & FAULT_IMPRECISE) != 0 && 635 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 636 /* 637 * Oops, an imprecise, double abort fault. We've lost the 638 * r14_abt/spsr_abt values corresponding to the original 639 * abort, and the spsr saved in the trapframe indicates 640 * ABT mode. 641 */ 642 tf->tf_spsr &= ~PSR_MODE; 643 644 /* 645 * We use a simple heuristic to determine if the double abort 646 * happened as a result of a kernel or user mode access. 647 * If the current trapframe is at the top of the kernel stack, 648 * the fault _must_ have come from user mode. 649 */ 650 if (tf != ((trapframe_t *)pcb->pcb_un.un_32.pcb32_sp) - 1) { 651 /* 652 * Kernel mode. We're either about to die a 653 * spectacular death, or pcb_onfault will come 654 * to our rescue. Either way, the current value 655 * of tf->tf_pc is irrelevant. 656 */ 657 tf->tf_spsr |= PSR_SVC32_MODE; 658 if (pcb->pcb_onfault == NULL) 659 printf("\nKernel mode double abort!\n"); 660 } else { 661 /* 662 * User mode. We've lost the program counter at the 663 * time of the fault (not that it was accurate anyway; 664 * it's not called an imprecise fault for nothing). 665 * About all we can do is copy r14_usr to tf_pc and 666 * hope for the best. The process is about to get a 667 * SIGBUS, so it's probably history anyway. 668 */ 669 tf->tf_spsr |= PSR_USR32_MODE; 670 tf->tf_pc = tf->tf_usr_lr; 671 #ifdef THUMB_CODE 672 tf->tf_spsr &= ~PSR_T_bit; 673 if (tf->tf_usr_lr & 1) 674 tf->tf_spsr |= PSR_T_bit; 675 #endif 676 } 677 } 678 679 /* FAR is invalid for imprecise exceptions */ 680 if ((fsr & FAULT_IMPRECISE) != 0) 681 far = 0; 682 #endif /* __XSCALE__ */ 683 684 if (pcb->pcb_onfault) { 685 KDASSERT(TRAP_USERMODE(tf) == 0); 686 tf->tf_r0 = EFAULT; 687 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 688 return (0); 689 } 690 691 /* See if the CPU state needs to be fixed up */ 692 (void) data_abort_fixup(tf, fsr, far, l); 693 694 /* 695 * At this point, if the fault happened in kernel mode, we're toast 696 */ 697 if (!TRAP_USERMODE(tf)) 698 dab_fatal(tf, fsr, far, l, NULL); 699 700 /* Deliver a bus error signal to the process */ 701 KSI_INIT_TRAP(ksi); 702 ksi->ksi_signo = SIGBUS; 703 ksi->ksi_code = BUS_ADRERR; 704 ksi->ksi_addr = (u_int32_t *)(intptr_t)far; 705 ksi->ksi_trap = fsr; 706 707 l->l_addr->u_pcb.pcb_tf = tf; 708 709 return (1); 710 } 711 712 static inline int 713 prefetch_abort_fixup(trapframe_t *tf) 714 { 715 #ifdef CPU_ABORT_FIXUP_REQUIRED 716 int error; 717 718 /* Call the CPU specific prefetch abort fixup routine */ 719 error = cpu_prefetchabt_fixup(tf); 720 if (__predict_true(error != ABORT_FIXUP_FAILED)) 721 return (error); 722 723 /* 724 * Oops, couldn't fix up the instruction 725 */ 726 printf( 727 "prefetch_abort_fixup: fixup for %s mode prefetch abort failed.\n", 728 TRAP_USERMODE(tf) ? "user" : "kernel"); 729 #ifdef THUMB_CODE 730 if (tf->tf_spsr & PSR_T_bit) { 731 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 732 tf->tf_pc, *((u_int16 *)(tf->tf_pc & ~1), 733 *((u_int16 *)((tf->tf_pc + 2) & ~1)); 734 } 735 else 736 #endif 737 { 738 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 739 *((u_int *)tf->tf_pc)); 740 } 741 disassemble(tf->tf_pc); 742 743 /* Die now if this happened in kernel mode */ 744 if (!TRAP_USERMODE(tf)) 745 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 746 747 return (error); 748 #else 749 return (ABORT_FIXUP_OK); 750 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 751 } 752 753 /* 754 * void prefetch_abort_handler(trapframe_t *tf) 755 * 756 * Abort handler called when instruction execution occurs at 757 * a non existent or restricted (access permissions) memory page. 758 * If the address is invalid and we were in SVC mode then panic as 759 * the kernel should never prefetch abort. 760 * If the address is invalid and the page is mapped then the user process 761 * does no have read permission so send it a signal. 762 * Otherwise fault the page in and try again. 763 */ 764 void 765 prefetch_abort_handler(trapframe_t *tf) 766 { 767 struct lwp *l; 768 struct vm_map *map; 769 vaddr_t fault_pc, va; 770 ksiginfo_t ksi; 771 int error; 772 773 UVMHIST_FUNC("prefetch_abort_handler"); UVMHIST_CALLED(maphist); 774 775 /* Update vmmeter statistics */ 776 uvmexp.traps++; 777 778 /* 779 * Enable IRQ's (disabled by the abort) This always comes 780 * from user mode so we know interrupts were not disabled. 781 * But we check anyway. 782 */ 783 if (__predict_true((tf->tf_spsr & I32_bit) == 0)) 784 enable_interrupts(I32_bit); 785 786 /* See if the CPU state needs to be fixed up */ 787 switch (prefetch_abort_fixup(tf)) { 788 case ABORT_FIXUP_RETURN: 789 return; 790 case ABORT_FIXUP_FAILED: 791 /* Deliver a SIGILL to the process */ 792 KSI_INIT_TRAP(&ksi); 793 ksi.ksi_signo = SIGILL; 794 ksi.ksi_code = ILL_ILLOPC; 795 ksi.ksi_addr = (u_int32_t *)(intptr_t) tf->tf_pc; 796 l = curlwp; 797 l->l_addr->u_pcb.pcb_tf = tf; 798 goto do_trapsignal; 799 default: 800 break; 801 } 802 803 /* Prefetch aborts cannot happen in kernel mode */ 804 if (__predict_false(!TRAP_USERMODE(tf))) 805 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 806 807 /* Get fault address */ 808 fault_pc = tf->tf_pc; 809 l = curlwp; 810 l->l_addr->u_pcb.pcb_tf = tf; 811 UVMHIST_LOG(maphist, " (pc=0x%x, l=0x%x, tf=0x%x)", fault_pc, l, tf, 812 0); 813 814 /* Ok validate the address, can only execute in USER space */ 815 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 816 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 817 KSI_INIT_TRAP(&ksi); 818 ksi.ksi_signo = SIGSEGV; 819 ksi.ksi_code = SEGV_ACCERR; 820 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 821 ksi.ksi_trap = fault_pc; 822 goto do_trapsignal; 823 } 824 825 map = &l->l_proc->p_vmspace->vm_map; 826 va = trunc_page(fault_pc); 827 828 /* 829 * See if the pmap can handle this fault on its own... 830 */ 831 #ifdef DEBUG 832 last_fault_code = -1; 833 #endif 834 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1)) { 835 UVMHIST_LOG (maphist, " <- emulated", 0, 0, 0, 0); 836 goto out; 837 } 838 839 #ifdef DIAGNOSTIC 840 if (__predict_false(current_intr_depth > 0)) { 841 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 842 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 843 } 844 #endif 845 if (map != kernel_map && l->l_flag & L_SA) { 846 l->l_savp->savp_faultaddr = fault_pc; 847 l->l_flag |= L_SA_PAGEFAULT; 848 } 849 850 error = uvm_fault(map, va, VM_PROT_READ); 851 852 if (map != kernel_map) 853 l->l_flag &= ~L_SA_PAGEFAULT; 854 855 if (__predict_true(error == 0)) { 856 UVMHIST_LOG (maphist, " <- uvm", 0, 0, 0, 0); 857 goto out; 858 } 859 KSI_INIT_TRAP(&ksi); 860 861 UVMHIST_LOG (maphist, " <- fatal (%d)", error, 0, 0, 0); 862 if (error == ENOMEM) { 863 printf("UVM: pid %d (%s), uid %d killed: " 864 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 865 l->l_proc->p_cred ? kauth_cred_geteuid(l->l_proc->p_cred) : -1); 866 ksi.ksi_signo = SIGKILL; 867 } else 868 ksi.ksi_signo = SIGSEGV; 869 870 ksi.ksi_code = SEGV_MAPERR; 871 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc; 872 ksi.ksi_trap = fault_pc; 873 874 do_trapsignal: 875 call_trapsignal(l, &ksi); 876 877 out: 878 userret(l); 879 } 880 881 /* 882 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 883 * If the read succeeds, the value is written to 'rptr' and zero is returned. 884 * Else, return EFAULT. 885 */ 886 int 887 badaddr_read(void *addr, size_t size, void *rptr) 888 { 889 extern int badaddr_read_1(const uint8_t *, uint8_t *); 890 extern int badaddr_read_2(const uint16_t *, uint16_t *); 891 extern int badaddr_read_4(const uint32_t *, uint32_t *); 892 union { 893 uint8_t v1; 894 uint16_t v2; 895 uint32_t v4; 896 } u; 897 struct pcb *curpcb_save; 898 int rv, s; 899 900 cpu_drain_writebuf(); 901 902 /* 903 * We might be called at interrupt time, so arrange to steal 904 * lwp0's PCB temporarily, if required, so that pcb_onfault 905 * handling works correctly. 906 */ 907 s = splhigh(); 908 if ((curpcb_save = curpcb) == NULL) 909 curpcb = &lwp0.l_addr->u_pcb; 910 911 /* Read from the test address. */ 912 switch (size) { 913 case sizeof(uint8_t): 914 rv = badaddr_read_1(addr, &u.v1); 915 if (rv == 0 && rptr) 916 *(uint8_t *) rptr = u.v1; 917 break; 918 919 case sizeof(uint16_t): 920 rv = badaddr_read_2(addr, &u.v2); 921 if (rv == 0 && rptr) 922 *(uint16_t *) rptr = u.v2; 923 break; 924 925 case sizeof(uint32_t): 926 rv = badaddr_read_4(addr, &u.v4); 927 if (rv == 0 && rptr) 928 *(uint32_t *) rptr = u.v4; 929 break; 930 931 default: 932 curpcb = curpcb_save; 933 panic("badaddr: invalid size (%lu)", (u_long) size); 934 } 935 936 /* Restore curpcb */ 937 curpcb = curpcb_save; 938 splx(s); 939 940 /* Return EFAULT if the address was invalid, else zero */ 941 return (rv); 942 } 943
Indexes created Wed Sep 24 14:09:57 GMT 2025