1 /* $NetBSD: fault.c,v 1.116 2021/02/01 19:31:34 skrll 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 #include "opt_multiprocessor.h" 83 84 #include <sys/types.h> 85 __KERNEL_RCSID(0, "$NetBSD: fault.c,v 1.116 2021/02/01 19:31:34 skrll Exp $"); 86 87 #include <sys/param.h> 88 89 #include <sys/cpu.h> 90 #include <sys/intr.h> 91 #include <sys/kauth.h> 92 #include <sys/kernel.h> 93 #include <sys/proc.h> 94 #include <sys/systm.h> 95 96 #include <uvm/uvm_extern.h> 97 #include <uvm/uvm_stat.h> 98 #ifdef UVMHIST 99 #include <uvm/uvm.h> 100 #endif 101 102 #include <arm/locore.h> 103 104 #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 #if defined(DEBUG) && !defined(MULTIPROCESSOR) 119 int last_fault_code; /* For the benefit of pmap_fault_fixup() */ 120 #endif 121 122 #if defined(CPU_ARM6) || defined(CPU_ARM7) || defined(CPU_ARM7TDMI) 123 /* These CPUs may need data/prefetch abort fixups */ 124 #define CPU_ABORT_FIXUP_REQUIRED 125 #endif 126 127 struct data_abort { 128 int (*func)(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 129 const char *desc; 130 }; 131 132 static int dab_fatal(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 133 static int dab_align(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 134 static int dab_buserr(trapframe_t *, u_int, u_int, struct lwp *, ksiginfo_t *); 135 136 static const struct data_abort data_aborts[] = { 137 {dab_fatal, "Vector Exception"}, 138 {dab_align, "Alignment Fault 1"}, 139 {dab_fatal, "Terminal Exception"}, 140 {dab_align, "Alignment Fault 3"}, 141 {dab_buserr, "External Linefetch Abort (S)"}, 142 {NULL, "Translation Fault (S)"}, 143 {dab_buserr, "External Linefetch Abort (P)"}, 144 {NULL, "Translation Fault (P)"}, 145 {dab_buserr, "External Non-Linefetch Abort (S)"}, 146 {NULL, "Domain Fault (S)"}, 147 {dab_buserr, "External Non-Linefetch Abort (P)"}, 148 {NULL, "Domain Fault (P)"}, 149 {dab_buserr, "External Translation Abort (L1)"}, 150 {NULL, "Permission Fault (S)"}, 151 {dab_buserr, "External Translation Abort (L2)"}, 152 {NULL, "Permission Fault (P)"} 153 }; 154 155 /* Determine if 'x' is a permission fault */ 156 #define IS_PERMISSION_FAULT(x) \ 157 (((1 << ((x) & FAULT_TYPE_MASK)) & \ 158 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) 159 160 #if 0 161 /* maybe one day we'll do emulations */ 162 #define TRAPSIGNAL(l,k) (*(l)->l_proc->p_emul->e_trapsignal)((l), (k)) 163 #else 164 #define TRAPSIGNAL(l,k) trapsignal((l), (k)) 165 #endif 166 167 static inline void 168 call_trapsignal(struct lwp *l, const struct trapframe *tf, ksiginfo_t *ksi) 169 { 170 if (l->l_proc->p_pid == 1 || cpu_printfataltraps) { 171 printf("%d.%d(%s): trap: signo=%d code=%d addr=%p trap=%#x\n", 172 l->l_proc->p_pid, l->l_lid, l->l_proc->p_comm, 173 ksi->ksi_signo, ksi->ksi_code, ksi->ksi_addr, 174 ksi->ksi_trap); 175 printf("r0=%08x r1=%08x r2=%08x r3=%08x\n", 176 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 177 printf("r4=%08x r5=%08x r6=%08x r7=%08x\n", 178 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 179 printf("r8=%08x r9=%08x rA=%08x rB=%08x\n", 180 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 181 printf("ip=%08x sp=%08x lr=%08x pc=%08x spsr=%08x\n", 182 tf->tf_r12, tf->tf_usr_sp, tf->tf_usr_lr, tf->tf_pc, 183 tf->tf_spsr); 184 } 185 186 TRAPSIGNAL(l, ksi); 187 } 188 189 static inline int 190 data_abort_fixup(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l) 191 { 192 #ifdef CPU_ABORT_FIXUP_REQUIRED 193 int error; 194 195 /* Call the CPU specific data abort fixup routine */ 196 error = cpu_dataabt_fixup(tf); 197 if (__predict_true(error != ABORT_FIXUP_FAILED)) 198 return error; 199 200 /* 201 * Oops, couldn't fix up the instruction 202 */ 203 printf("%s: fixup for %s mode data abort failed.\n", __func__, 204 TRAP_USERMODE(tf) ? "user" : "kernel"); 205 #ifdef THUMB_CODE 206 if (tf->tf_spsr & PSR_T_bit) { 207 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 208 tf->tf_pc, *((uint16 *)(tf->tf_pc & ~1)), 209 *((uint16 *)((tf->tf_pc + 2) & ~1))); 210 } 211 else 212 #endif 213 { 214 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 215 *((u_int *)tf->tf_pc)); 216 } 217 disassemble(tf->tf_pc); 218 219 /* Die now if this happened in kernel mode */ 220 if (!TRAP_USERMODE(tf)) 221 dab_fatal(tf, fsr, far, l, NULL); 222 223 return error; 224 #else 225 return ABORT_FIXUP_OK; 226 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 227 } 228 229 void 230 data_abort_handler(trapframe_t *tf) 231 { 232 struct vm_map *map; 233 struct lwp * const l = curlwp; 234 struct cpu_info * const ci = curcpu(); 235 u_int far, fsr; 236 vm_prot_t ftype; 237 void *onfault; 238 vaddr_t va; 239 int error; 240 ksiginfo_t ksi; 241 242 UVMHIST_FUNC(__func__); 243 UVMHIST_CALLED(maphist); 244 245 /* Grab FAR/FSR before enabling interrupts */ 246 far = cpu_faultaddress(); 247 fsr = cpu_faultstatus(); 248 249 /* Update vmmeter statistics */ 250 ci->ci_data.cpu_ntrap++; 251 252 /* Re-enable interrupts if they were enabled previously */ 253 KASSERT(!TRAP_USERMODE(tf) || VALID_PSR(tf->tf_spsr)); 254 #ifdef __NO_FIQ 255 if (__predict_true((tf->tf_spsr & I32_bit) != I32_bit)) 256 restore_interrupts(tf->tf_spsr & IF32_bits); 257 #else 258 if (__predict_true((tf->tf_spsr & IF32_bits) != IF32_bits)) 259 restore_interrupts(tf->tf_spsr & IF32_bits); 260 #endif 261 262 /* Get the current lwp structure */ 263 264 UVMHIST_LOG(maphist, " (l=%#jx, far=%#jx, fsr=%#jx", 265 (uintptr_t)l, far, fsr, 0); 266 UVMHIST_LOG(maphist, " tf=%#jx, pc=%#jx)", 267 (uintptr_t)tf, (uintptr_t)tf->tf_pc, 0, 0); 268 269 /* Data abort came from user mode? */ 270 bool user = (TRAP_USERMODE(tf) != 0); 271 if (user) 272 LWP_CACHE_CREDS(l, l->l_proc); 273 274 /* Grab the current pcb */ 275 struct pcb * const pcb = lwp_getpcb(l); 276 277 curcpu()->ci_abt_evs[fsr & FAULT_TYPE_MASK].ev_count++; 278 279 /* Invoke the appropriate handler, if necessary */ 280 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 281 #ifdef DIAGNOSTIC 282 printf("%s: data_aborts fsr=0x%x far=0x%x\n", 283 __func__, fsr, far); 284 #endif 285 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, 286 l, &ksi)) 287 goto do_trapsignal; 288 goto out; 289 } 290 291 /* 292 * At this point, we're dealing with one of the following data aborts: 293 * 294 * FAULT_TRANS_S - Translation -- Section 295 * FAULT_TRANS_P - Translation -- Page 296 * FAULT_DOMAIN_S - Domain -- Section 297 * FAULT_DOMAIN_P - Domain -- Page 298 * FAULT_PERM_S - Permission -- Section 299 * FAULT_PERM_P - Permission -- Page 300 * 301 * These are the main virtual memory-related faults signalled by 302 * the MMU. 303 */ 304 305 KASSERTMSG(!user || tf == lwp_trapframe(l), "tf %p vs %p", tf, 306 lwp_trapframe(l)); 307 308 /* 309 * Make sure the Program Counter is sane. We could fall foul of 310 * someone executing Thumb code, in which case the PC might not 311 * be word-aligned. This would cause a kernel alignment fault 312 * further down if we have to decode the current instruction. 313 */ 314 #ifdef THUMB_CODE 315 /* 316 * XXX: It would be nice to be able to support Thumb in the kernel 317 * at some point. 318 */ 319 if (__predict_false(!user && (tf->tf_pc & 3) != 0)) { 320 printf("\n%s: Misaligned Kernel-mode Program Counter\n", 321 __func__); 322 dab_fatal(tf, fsr, far, l, NULL); 323 } 324 #else 325 if (__predict_false((tf->tf_pc & 3) != 0)) { 326 if (user) { 327 /* 328 * Give the user an illegal instruction signal. 329 */ 330 /* Deliver a SIGILL to the process */ 331 KSI_INIT_TRAP(&ksi); 332 ksi.ksi_signo = SIGILL; 333 ksi.ksi_code = ILL_ILLOPC; 334 ksi.ksi_addr = (uint32_t *)(intptr_t) far; 335 ksi.ksi_trap = fsr; 336 goto do_trapsignal; 337 } 338 339 /* 340 * The kernel never executes Thumb code. 341 */ 342 printf("\n%s: Misaligned Kernel-mode Program Counter\n", 343 __func__); 344 dab_fatal(tf, fsr, far, l, NULL); 345 } 346 #endif 347 348 /* See if the CPU state needs to be fixed up */ 349 switch (data_abort_fixup(tf, fsr, far, l)) { 350 case ABORT_FIXUP_RETURN: 351 return; 352 case ABORT_FIXUP_FAILED: 353 /* Deliver a SIGILL to the process */ 354 KSI_INIT_TRAP(&ksi); 355 ksi.ksi_signo = SIGILL; 356 ksi.ksi_code = ILL_ILLOPC; 357 ksi.ksi_addr = (uint32_t *)(intptr_t) far; 358 ksi.ksi_trap = fsr; 359 goto do_trapsignal; 360 default: 361 break; 362 } 363 364 va = trunc_page((vaddr_t)far); 365 366 /* 367 * It is only a kernel address space fault iff: 368 * 1. user == 0 and 369 * 2. pcb_onfault not set or 370 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. 371 */ 372 if (!user && (va >= VM_MIN_KERNEL_ADDRESS || 373 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && 374 __predict_true((pcb->pcb_onfault == NULL || 375 (read_insn(tf->tf_pc, false) & 0x05200000) != 0x04200000))) { 376 map = kernel_map; 377 378 /* Was the fault due to the FPE ? */ 379 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { 380 KSI_INIT_TRAP(&ksi); 381 ksi.ksi_signo = SIGSEGV; 382 ksi.ksi_code = SEGV_ACCERR; 383 ksi.ksi_addr = (uint32_t *)(intptr_t) far; 384 ksi.ksi_trap = fsr; 385 386 /* 387 * Force exit via userret() 388 * This is necessary as the FPE is an extension to 389 * userland that actually runs in a priveledged mode 390 * but uses USR mode permissions for its accesses. 391 */ 392 user = true; 393 goto do_trapsignal; 394 } 395 } else { 396 map = &l->l_proc->p_vmspace->vm_map; 397 } 398 399 /* 400 * We need to know whether the page should be mapped as R or R/W. 401 * Before ARMv6, the MMU did not give us the info as to whether the 402 * fault was caused by a read or a write. 403 * 404 * However, we know that a permission fault can only be the result of 405 * a write to a read-only location, so we can deal with those quickly. 406 * 407 * Otherwise we need to disassemble the instruction responsible to 408 * determine if it was a write. 409 */ 410 if (CPU_IS_ARMV6_P() || CPU_IS_ARMV7_P()) { 411 ftype = (fsr & FAULT_WRITE) ? VM_PROT_WRITE : VM_PROT_READ; 412 } else if (IS_PERMISSION_FAULT(fsr)) { 413 ftype = VM_PROT_WRITE; 414 } else { 415 #ifdef THUMB_CODE 416 /* Fast track the ARM case. */ 417 if (__predict_false(tf->tf_spsr & PSR_T_bit)) { 418 u_int insn = read_thumb_insn(tf->tf_pc, user); 419 u_int insn_f8 = insn & 0xf800; 420 u_int insn_fe = insn & 0xfe00; 421 422 if (insn_f8 == 0x6000 || /* STR(1) */ 423 insn_f8 == 0x7000 || /* STRB(1) */ 424 insn_f8 == 0x8000 || /* STRH(1) */ 425 insn_f8 == 0x9000 || /* STR(3) */ 426 insn_f8 == 0xc000 || /* STM */ 427 insn_fe == 0x5000 || /* STR(2) */ 428 insn_fe == 0x5200 || /* STRH(2) */ 429 insn_fe == 0x5400) /* STRB(2) */ 430 ftype = VM_PROT_WRITE; 431 else 432 ftype = VM_PROT_READ; 433 } 434 else 435 #endif 436 { 437 u_int insn = read_insn(tf->tf_pc, user); 438 439 if (((insn & 0x0c100000) == 0x04000000) || /* STR[B] */ 440 ((insn & 0x0e1000b0) == 0x000000b0) || /* STR[HD]*/ 441 ((insn & 0x0a100000) == 0x08000000) || /* STM/CDT*/ 442 ((insn & 0x0f9000f0) == 0x01800090)) /* STREX[BDH] */ 443 ftype = VM_PROT_WRITE; 444 else if ((insn & 0x0fb00ff0) == 0x01000090)/* SWP */ 445 ftype = VM_PROT_READ | VM_PROT_WRITE; 446 else 447 ftype = VM_PROT_READ; 448 } 449 } 450 451 /* 452 * See if the fault is as a result of ref/mod emulation, 453 * or domain mismatch. 454 */ 455 #if defined(DEBUG) && !defined(MULTIPROCESSOR) 456 last_fault_code = fsr; 457 #endif 458 if (pmap_fault_fixup(map->pmap, va, ftype, user)) { 459 UVMHIST_LOG(maphist, " <- ref/mod emul", 0, 0, 0, 0); 460 goto out; 461 } 462 463 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 464 if (pcb->pcb_onfault) { 465 tf->tf_r0 = EINVAL; 466 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 467 return; 468 } 469 printf("\nNon-emulated page fault with intr_depth > 0\n"); 470 dab_fatal(tf, fsr, far, l, NULL); 471 } 472 473 #ifdef PMAP_FAULTINFO 474 struct pcb_faultinfo * const pfi = &pcb->pcb_faultinfo; 475 struct proc * const p = curproc; 476 477 if (p->p_pid == pfi->pfi_lastpid && va == pfi->pfi_faultaddr) { 478 if (++pfi->pfi_repeats > 4) { 479 tlb_asid_t asid = tlb_get_asid(); 480 pt_entry_t *ptep = pfi->pfi_faultptep; 481 482 printf("%s: fault #%u (%x/%s) for %#" PRIxVADDR 483 "(%#x) at pc %#" PRIxREGISTER " curpid=%u/%u " 484 "ptep@%p=%#" PRIxPTE ")\n", __func__, 485 pfi->pfi_repeats, fsr & FAULT_TYPE_MASK, 486 data_aborts[fsr & FAULT_TYPE_MASK].desc, va, 487 far, tf->tf_pc, map->pmap->pm_pai[0].pai_asid, 488 asid, ptep, ptep ? *ptep : 0); 489 cpu_Debugger(); 490 } 491 } else { 492 pfi->pfi_lastpid = p->p_pid; 493 pfi->pfi_faultaddr = va; 494 pfi->pfi_repeats = 0; 495 pfi->pfi_faultptep = NULL; 496 pfi->pfi_faulttype = fsr & FAULT_TYPE_MASK; 497 } 498 #endif /* PMAP_FAULTINFO */ 499 500 onfault = pcb->pcb_onfault; 501 pcb->pcb_onfault = NULL; 502 error = uvm_fault(map, va, ftype); 503 pcb->pcb_onfault = onfault; 504 505 if (__predict_true(error == 0)) { 506 if (user) 507 uvm_grow(l->l_proc, va); /* Record any stack growth */ 508 UVMHIST_LOG(maphist, " <- uvm", 0, 0, 0, 0); 509 goto out; 510 } 511 512 if (user == 0) { 513 if (pcb->pcb_onfault) { 514 tf->tf_r0 = error; 515 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 516 return; 517 } 518 519 printf("\nuvm_fault(%p, %lx, %x) -> %x\n", map, va, ftype, 520 error); 521 dab_fatal(tf, fsr, far, l, NULL); 522 } 523 524 KSI_INIT_TRAP(&ksi); 525 526 switch (error) { 527 case ENOMEM: 528 printf("UVM: pid %d (%s), uid %d killed: " 529 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 530 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 531 ksi.ksi_signo = SIGKILL; 532 break; 533 case EACCES: 534 ksi.ksi_signo = SIGSEGV; 535 ksi.ksi_code = SEGV_ACCERR; 536 break; 537 case EINVAL: 538 ksi.ksi_signo = SIGBUS; 539 ksi.ksi_code = BUS_ADRERR; 540 break; 541 default: 542 ksi.ksi_signo = SIGSEGV; 543 ksi.ksi_code = SEGV_MAPERR; 544 break; 545 } 546 ksi.ksi_addr = (uint32_t *)(intptr_t) far; 547 ksi.ksi_trap = fsr; 548 UVMHIST_LOG(maphist, " <- error (%jd)", error, 0, 0, 0); 549 550 do_trapsignal: 551 call_trapsignal(l, tf, &ksi); 552 out: 553 /* If returning to user mode, make sure to invoke userret() */ 554 if (user) 555 userret(l); 556 } 557 558 /* 559 * dab_fatal() handles the following data aborts: 560 * 561 * FAULT_WRTBUF_0 - Vector Exception 562 * FAULT_WRTBUF_1 - Terminal Exception 563 * 564 * We should never see these on a properly functioning system. 565 * 566 * This function is also called by the other handlers if they 567 * detect a fatal problem. 568 * 569 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 570 */ 571 static int 572 dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 573 { 574 const char * const mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 575 576 if (l != NULL) { 577 printf("Fatal %s mode data abort: '%s'\n", mode, 578 data_aborts[fsr & FAULT_TYPE_MASK].desc); 579 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 580 if ((fsr & FAULT_IMPRECISE) == 0) 581 printf("%08x, ", far); 582 else 583 printf("Invalid, "); 584 printf("spsr=%08x\n", tf->tf_spsr); 585 } else { 586 printf("Fatal %s mode prefetch abort at 0x%08x\n", 587 mode, tf->tf_pc); 588 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 589 } 590 591 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 592 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 593 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 594 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 595 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 596 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 597 printf("r12=%08x, ", tf->tf_r12); 598 599 if (TRAP_USERMODE(tf)) 600 printf("usp=%08x, ulr=%08x", 601 tf->tf_usr_sp, tf->tf_usr_lr); 602 else 603 printf("ssp=%08x, slr=%08x", 604 tf->tf_svc_sp, tf->tf_svc_lr); 605 printf(", pc =%08x\n\n", tf->tf_pc); 606 607 #if defined(DDB) || defined(KGDB) 608 kdb_trap(T_FAULT, tf); 609 #endif 610 panic("Fatal abort"); 611 /*NOTREACHED*/ 612 } 613 614 /* 615 * dab_align() handles the following data aborts: 616 * 617 * FAULT_ALIGN_0 - Alignment fault 618 * FAULT_ALIGN_0 - Alignment fault 619 * 620 * These faults are fatal if they happen in kernel mode. Otherwise, we 621 * deliver a bus error to the process. 622 */ 623 static int 624 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 625 { 626 /* Alignment faults are always fatal if they occur in kernel mode */ 627 if (!TRAP_USERMODE(tf)) 628 dab_fatal(tf, fsr, far, l, NULL); 629 630 /* pcb_onfault *must* be NULL at this point */ 631 KDASSERT(((struct pcb *)lwp_getpcb(l))->pcb_onfault == NULL); 632 633 /* See if the CPU state needs to be fixed up */ 634 (void) data_abort_fixup(tf, fsr, far, l); 635 636 /* Deliver a bus error signal to the process */ 637 KSI_INIT_TRAP(ksi); 638 ksi->ksi_signo = SIGBUS; 639 ksi->ksi_code = BUS_ADRALN; 640 ksi->ksi_addr = (uint32_t *)(intptr_t)far; 641 ksi->ksi_trap = fsr; 642 643 KASSERTMSG(tf == lwp_trapframe(l), "tf %p vs %p", tf, lwp_trapframe(l)); 644 645 return 1; 646 } 647 648 /* 649 * dab_buserr() handles the following data aborts: 650 * 651 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 652 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 653 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 654 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 655 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 656 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 657 * 658 * If pcb_onfault is set, flag the fault and return to the handler. 659 * If the fault occurred in user mode, give the process a SIGBUS. 660 * 661 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 662 * can be flagged as imprecise in the FSR. This causes a real headache 663 * since some of the machine state is lost. In this case, tf->tf_pc 664 * may not actually point to the offending instruction. In fact, if 665 * we've taken a double abort fault, it generally points somewhere near 666 * the top of "data_abort_entry" in exception.S. 667 * 668 * In all other cases, these data aborts are considered fatal. 669 */ 670 static int 671 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 672 ksiginfo_t *ksi) 673 { 674 struct pcb *pcb = lwp_getpcb(l); 675 676 #ifdef __XSCALE__ 677 if ((fsr & FAULT_IMPRECISE) != 0 && 678 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 679 /* 680 * Oops, an imprecise, double abort fault. We've lost the 681 * r14_abt/spsr_abt values corresponding to the original 682 * abort, and the spsr saved in the trapframe indicates 683 * ABT mode. 684 */ 685 tf->tf_spsr &= ~PSR_MODE; 686 687 /* 688 * We use a simple heuristic to determine if the double abort 689 * happened as a result of a kernel or user mode access. 690 * If the current trapframe is at the top of the kernel stack, 691 * the fault _must_ have come from user mode. 692 */ 693 if (tf != ((trapframe_t *)pcb->pcb_ksp) - 1) { 694 /* 695 * Kernel mode. We're either about to die a 696 * spectacular death, or pcb_onfault will come 697 * to our rescue. Either way, the current value 698 * of tf->tf_pc is irrelevant. 699 */ 700 tf->tf_spsr |= PSR_SVC32_MODE; 701 if (pcb->pcb_onfault == NULL) 702 printf("\nKernel mode double abort!\n"); 703 } else { 704 /* 705 * User mode. We've lost the program counter at the 706 * time of the fault (not that it was accurate anyway; 707 * it's not called an imprecise fault for nothing). 708 * About all we can do is copy r14_usr to tf_pc and 709 * hope for the best. The process is about to get a 710 * SIGBUS, so it's probably history anyway. 711 */ 712 tf->tf_spsr |= PSR_USR32_MODE; 713 tf->tf_pc = tf->tf_usr_lr; 714 #ifdef THUMB_CODE 715 tf->tf_spsr &= ~PSR_T_bit; 716 if (tf->tf_usr_lr & 1) 717 tf->tf_spsr |= PSR_T_bit; 718 #endif 719 } 720 } 721 722 /* FAR is invalid for imprecise exceptions */ 723 if ((fsr & FAULT_IMPRECISE) != 0) 724 far = 0; 725 #endif /* __XSCALE__ */ 726 727 if (pcb->pcb_onfault) { 728 KDASSERT(TRAP_USERMODE(tf) == 0); 729 tf->tf_r0 = EFAULT; 730 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 731 return 0; 732 } 733 734 /* See if the CPU state needs to be fixed up */ 735 (void) data_abort_fixup(tf, fsr, far, l); 736 737 /* 738 * At this point, if the fault happened in kernel mode, we're toast 739 */ 740 if (!TRAP_USERMODE(tf)) 741 dab_fatal(tf, fsr, far, l, NULL); 742 743 /* Deliver a bus error signal to the process */ 744 KSI_INIT_TRAP(ksi); 745 ksi->ksi_signo = SIGBUS; 746 ksi->ksi_code = BUS_ADRERR; 747 ksi->ksi_addr = (uint32_t *)(intptr_t)far; 748 ksi->ksi_trap = fsr; 749 750 KASSERTMSG(tf == lwp_trapframe(l), "tf %p vs %p", tf, lwp_trapframe(l)); 751 752 return 1; 753 } 754 755 static inline int 756 prefetch_abort_fixup(trapframe_t *tf) 757 { 758 #ifdef CPU_ABORT_FIXUP_REQUIRED 759 int error; 760 761 /* Call the CPU specific prefetch abort fixup routine */ 762 error = cpu_prefetchabt_fixup(tf); 763 if (__predict_true(error != ABORT_FIXUP_FAILED)) 764 return error; 765 766 /* 767 * Oops, couldn't fix up the instruction 768 */ 769 printf("%s: fixup for %s mode prefetch abort failed.\n", __func__, 770 TRAP_USERMODE(tf) ? "user" : "kernel"); 771 #ifdef THUMB_CODE 772 if (tf->tf_spsr & PSR_T_bit) { 773 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 774 tf->tf_pc, *((uint16 *)(tf->tf_pc & ~1)), 775 *((uint16 *)((tf->tf_pc + 2) & ~1))); 776 } 777 else 778 #endif 779 { 780 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 781 *((u_int *)tf->tf_pc)); 782 } 783 disassemble(tf->tf_pc); 784 785 /* Die now if this happened in kernel mode */ 786 if (!TRAP_USERMODE(tf)) 787 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 788 789 return error; 790 #else 791 return ABORT_FIXUP_OK; 792 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 793 } 794 795 /* 796 * void prefetch_abort_handler(trapframe_t *tf) 797 * 798 * Abort handler called when instruction execution occurs at 799 * a non existent or restricted (access permissions) memory page. 800 * If the address is invalid and we were in SVC mode then panic as 801 * the kernel should never prefetch abort. 802 * If the address is invalid and the page is mapped then the user process 803 * does not have read permission so send it a signal. 804 * Otherwise fault the page in and try again. 805 */ 806 void 807 prefetch_abort_handler(trapframe_t *tf) 808 { 809 struct lwp *l; 810 struct pcb *pcb __diagused; 811 struct vm_map *map; 812 vaddr_t fault_pc, va; 813 ksiginfo_t ksi; 814 int error, user; 815 816 UVMHIST_FUNC(__func__); 817 UVMHIST_CALLED(maphist); 818 819 /* Update vmmeter statistics */ 820 curcpu()->ci_data.cpu_ntrap++; 821 822 l = curlwp; 823 pcb = lwp_getpcb(l); 824 825 if ((user = TRAP_USERMODE(tf)) != 0) 826 LWP_CACHE_CREDS(l, l->l_proc); 827 828 /* 829 * Enable IRQ's (disabled by the abort) This always comes 830 * from user mode so we know interrupts were not disabled. 831 * But we check anyway. 832 */ 833 KASSERT(!TRAP_USERMODE(tf) || VALID_PSR(tf->tf_spsr)); 834 #ifdef __NO_FIQ 835 if (__predict_true((tf->tf_spsr & I32_bit) != I32_bit)) 836 restore_interrupts(tf->tf_spsr & IF32_bits); 837 #else 838 if (__predict_true((tf->tf_spsr & IF32_bits) != IF32_bits)) 839 restore_interrupts(tf->tf_spsr & IF32_bits); 840 #endif 841 842 /* See if the CPU state needs to be fixed up */ 843 switch (prefetch_abort_fixup(tf)) { 844 case ABORT_FIXUP_RETURN: 845 KASSERT(!TRAP_USERMODE(tf) || VALID_PSR(tf->tf_spsr)); 846 return; 847 case ABORT_FIXUP_FAILED: 848 /* Deliver a SIGILL to the process */ 849 KSI_INIT_TRAP(&ksi); 850 ksi.ksi_signo = SIGILL; 851 ksi.ksi_code = ILL_ILLOPC; 852 ksi.ksi_addr = (uint32_t *)(intptr_t) tf->tf_pc; 853 KASSERTMSG(tf == lwp_trapframe(l), "tf %p vs %p", tf, 854 lwp_trapframe(l)); 855 goto do_trapsignal; 856 default: 857 break; 858 } 859 860 /* Prefetch aborts cannot happen in kernel mode */ 861 if (__predict_false(!user)) 862 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 863 864 /* Get fault address */ 865 fault_pc = tf->tf_pc; 866 KASSERTMSG(tf == lwp_trapframe(l), "tf %p vs %p", tf, lwp_trapframe(l)); 867 UVMHIST_LOG(maphist, " (pc=%#jx, l=%#jx, tf=%#jx)", 868 fault_pc, (uintptr_t)l, (uintptr_t)tf, 0); 869 870 #ifdef THUMB_CODE 871 recheck: 872 #endif 873 /* Ok validate the address, can only execute in USER space */ 874 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 875 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 876 KSI_INIT_TRAP(&ksi); 877 ksi.ksi_signo = SIGSEGV; 878 ksi.ksi_code = SEGV_ACCERR; 879 ksi.ksi_addr = (uint32_t *)(intptr_t) fault_pc; 880 ksi.ksi_trap = fault_pc; 881 goto do_trapsignal; 882 } 883 884 map = &l->l_proc->p_vmspace->vm_map; 885 va = trunc_page(fault_pc); 886 887 /* 888 * See if the pmap can handle this fault on its own... 889 */ 890 #if defined(DEBUG) && !defined(MULTIPROCESSOR) 891 last_fault_code = -1; 892 #endif 893 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ|VM_PROT_EXECUTE, 1)) { 894 UVMHIST_LOG (maphist, " <- emulated", 0, 0, 0, 0); 895 goto out; 896 } 897 898 #ifdef DIAGNOSTIC 899 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 900 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 901 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 902 } 903 #endif 904 905 KASSERT(pcb->pcb_onfault == NULL); 906 error = uvm_fault(map, va, VM_PROT_READ|VM_PROT_EXECUTE); 907 908 if (__predict_true(error == 0)) { 909 UVMHIST_LOG (maphist, " <- uvm", 0, 0, 0, 0); 910 goto out; 911 } 912 KSI_INIT_TRAP(&ksi); 913 914 UVMHIST_LOG (maphist, " <- fatal (%jd)", error, 0, 0, 0); 915 916 if (error == ENOMEM) { 917 printf("UVM: pid %d (%s), uid %d killed: " 918 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 919 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 920 ksi.ksi_signo = SIGKILL; 921 } else 922 ksi.ksi_signo = SIGSEGV; 923 924 ksi.ksi_code = SEGV_MAPERR; 925 ksi.ksi_addr = (uint32_t *)(intptr_t) fault_pc; 926 ksi.ksi_trap = fault_pc; 927 928 do_trapsignal: 929 call_trapsignal(l, tf, &ksi); 930 931 out: 932 933 #ifdef THUMB_CODE 934 #define THUMB_32BIT(hi) (((hi) & 0xe000) == 0xe000 && ((hi) & 0x1800)) 935 /* thumb-32 instruction was located on page boundary? */ 936 if ((tf->tf_spsr & PSR_T_bit) && 937 ((fault_pc & PAGE_MASK) == (PAGE_SIZE - THUMB_INSN_SIZE)) && 938 THUMB_32BIT(*(uint16_t *)tf->tf_pc)) { 939 fault_pc = tf->tf_pc + THUMB_INSN_SIZE; 940 goto recheck; 941 } 942 #endif /* THUMB_CODE */ 943 944 KASSERT(!TRAP_USERMODE(tf) || VALID_PSR(tf->tf_spsr)); 945 userret(l); 946 } 947 948 /* 949 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 950 * If the read succeeds, the value is written to 'rptr' and zero is returned. 951 * Else, return EFAULT. 952 */ 953 int 954 badaddr_read(void *addr, size_t size, void *rptr) 955 { 956 extern int badaddr_read_1(const uint8_t *, uint8_t *); 957 extern int badaddr_read_2(const uint16_t *, uint16_t *); 958 extern int badaddr_read_4(const uint32_t *, uint32_t *); 959 union { 960 uint8_t v1; 961 uint16_t v2; 962 uint32_t v4; 963 } u; 964 int rv, s; 965 966 cpu_drain_writebuf(); 967 968 s = splhigh(); 969 970 /* Read from the test address. */ 971 switch (size) { 972 case sizeof(uint8_t): 973 rv = badaddr_read_1(addr, &u.v1); 974 if (rv == 0 && rptr) 975 *(uint8_t *) rptr = u.v1; 976 break; 977 978 case sizeof(uint16_t): 979 rv = badaddr_read_2(addr, &u.v2); 980 if (rv == 0 && rptr) 981 *(uint16_t *) rptr = u.v2; 982 break; 983 984 case sizeof(uint32_t): 985 rv = badaddr_read_4(addr, &u.v4); 986 if (rv == 0 && rptr) 987 *(uint32_t *) rptr = u.v4; 988 break; 989 990 default: 991 panic("%s: invalid size (%zu)", __func__, size); 992 } 993 994 splx(s); 995 996 /* Return EFAULT if the address was invalid, else zero */ 997 return rv; 998 } 999