1 /* $NetBSD: fault.c,v 1.113 2020/06/20 15:45:22 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 83 #include <sys/types.h> 84 __KERNEL_RCSID(0, "$NetBSD: fault.c,v 1.113 2020/06/20 15:45:22 skrll Exp $"); 85 86 #include <sys/param.h> 87 88 #include <sys/cpu.h> 89 #include <sys/intr.h> 90 #include <sys/kauth.h> 91 #include <sys/kernel.h> 92 #include <sys/proc.h> 93 #include <sys/systm.h> 94 95 #include <uvm/uvm_extern.h> 96 #include <uvm/uvm_stat.h> 97 #ifdef UVMHIST 98 #include <uvm/uvm.h> 99 #endif 100 101 #include <arm/locore.h> 102 103 #include <machine/pcb.h> 104 #if defined(DDB) || defined(KGDB) 105 #include <machine/db_machdep.h> 106 #ifdef KGDB 107 #include <sys/kgdb.h> 108 #endif 109 #if !defined(DDB) 110 #define kdb_trap kgdb_trap 111 #endif 112 #endif 113 114 #include <arch/arm/arm/disassem.h> 115 #include <arm/arm32/machdep.h> 116 117 #ifdef DEBUG 118 int last_fault_code; /* For the benefit of pmap_fault_fixup() */ 119 #endif 120 121 #if defined(CPU_ARM6) || 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 'x' is a permission fault */ 155 #define IS_PERMISSION_FAULT(x) \ 156 (((1 << ((x) & FAULT_TYPE_MASK)) & \ 157 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) 158 159 #if 0 160 /* maybe one day we'll do emulations */ 161 #define TRAPSIGNAL(l,k) (*(l)->l_proc->p_emul->e_trapsignal)((l), (k)) 162 #else 163 #define TRAPSIGNAL(l,k) trapsignal((l), (k)) 164 #endif 165 166 static inline void 167 call_trapsignal(struct lwp *l, const struct trapframe *tf, ksiginfo_t *ksi) 168 { 169 if (l->l_proc->p_pid == 1 || cpu_printfataltraps) { 170 printf("%d.%d(%s): trap: signo=%d code=%d addr=%p trap=%#x\n", 171 l->l_proc->p_pid, l->l_lid, l->l_proc->p_comm, 172 ksi->ksi_signo, ksi->ksi_code, ksi->ksi_addr, 173 ksi->ksi_trap); 174 printf("r0=%08x r1=%08x r2=%08x r3=%08x\n", 175 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 176 printf("r4=%08x r5=%08x r6=%08x r7=%08x\n", 177 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 178 printf("r8=%08x r9=%08x rA=%08x rB=%08x\n", 179 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 180 printf("ip=%08x sp=%08x lr=%08x pc=%08x spsr=%08x\n", 181 tf->tf_r12, tf->tf_usr_sp, tf->tf_usr_lr, tf->tf_pc, 182 tf->tf_spsr); 183 } 184 185 TRAPSIGNAL(l, ksi); 186 } 187 188 static inline int 189 data_abort_fixup(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l) 190 { 191 #ifdef CPU_ABORT_FIXUP_REQUIRED 192 int error; 193 194 /* Call the CPU specific data abort fixup routine */ 195 error = cpu_dataabt_fixup(tf); 196 if (__predict_true(error != ABORT_FIXUP_FAILED)) 197 return error; 198 199 /* 200 * Oops, couldn't fix up the instruction 201 */ 202 printf("%s: fixup for %s mode data abort failed.\n", __func__, 203 TRAP_USERMODE(tf) ? "user" : "kernel"); 204 #ifdef THUMB_CODE 205 if (tf->tf_spsr & PSR_T_bit) { 206 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 207 tf->tf_pc, *((uint16 *)(tf->tf_pc & ~1)), 208 *((uint16 *)((tf->tf_pc + 2) & ~1))); 209 } 210 else 211 #endif 212 { 213 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 214 *((u_int *)tf->tf_pc)); 215 } 216 disassemble(tf->tf_pc); 217 218 /* Die now if this happened in kernel mode */ 219 if (!TRAP_USERMODE(tf)) 220 dab_fatal(tf, fsr, far, l, NULL); 221 222 return error; 223 #else 224 return ABORT_FIXUP_OK; 225 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 226 } 227 228 void 229 data_abort_handler(trapframe_t *tf) 230 { 231 struct vm_map *map; 232 struct lwp * const l = curlwp; 233 struct cpu_info * const ci = curcpu(); 234 u_int far, fsr; 235 vm_prot_t ftype; 236 void *onfault; 237 vaddr_t va; 238 int error; 239 ksiginfo_t ksi; 240 241 UVMHIST_FUNC(__func__); 242 UVMHIST_CALLED(maphist); 243 244 /* Grab FAR/FSR before enabling interrupts */ 245 far = cpu_faultaddress(); 246 fsr = cpu_faultstatus(); 247 248 /* Update vmmeter statistics */ 249 ci->ci_data.cpu_ntrap++; 250 251 /* Re-enable interrupts if they were enabled previously */ 252 KASSERT(!TRAP_USERMODE(tf) || VALID_R15_PSR(tf->tf_pc, tf->tf_spsr)); 253 #ifdef __NO_FIQ 254 if (__predict_true((tf->tf_spsr & I32_bit) != I32_bit)) 255 restore_interrupts(tf->tf_spsr & IF32_bits); 256 #else 257 if (__predict_true((tf->tf_spsr & IF32_bits) != IF32_bits)) 258 restore_interrupts(tf->tf_spsr & IF32_bits); 259 #endif 260 261 /* Get the current lwp structure */ 262 263 UVMHIST_LOG(maphist, " (l=%#jx, far=%#jx, fsr=%#jx", 264 (uintptr_t)l, far, fsr, 0); 265 UVMHIST_LOG(maphist, " tf=%#jx, pc=%#jx)", 266 (uintptr_t)tf, (uintptr_t)tf->tf_pc, 0, 0); 267 268 /* Data abort came from user mode? */ 269 bool user = (TRAP_USERMODE(tf) != 0); 270 if (user) 271 LWP_CACHE_CREDS(l, l->l_proc); 272 273 /* Grab the current pcb */ 274 struct pcb * const pcb = lwp_getpcb(l); 275 276 curcpu()->ci_abt_evs[fsr & FAULT_TYPE_MASK].ev_count++; 277 278 /* Invoke the appropriate handler, if necessary */ 279 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 280 #ifdef DIAGNOSTIC 281 printf("%s: data_aborts fsr=0x%x far=0x%x\n", 282 __func__, fsr, far); 283 #endif 284 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, 285 l, &ksi)) 286 goto do_trapsignal; 287 goto out; 288 } 289 290 /* 291 * At this point, we're dealing with one of the following data aborts: 292 * 293 * FAULT_TRANS_S - Translation -- Section 294 * FAULT_TRANS_P - Translation -- Page 295 * FAULT_DOMAIN_S - Domain -- Section 296 * FAULT_DOMAIN_P - Domain -- Page 297 * FAULT_PERM_S - Permission -- Section 298 * FAULT_PERM_P - Permission -- Page 299 * 300 * These are the main virtual memory-related faults signalled by 301 * the MMU. 302 */ 303 304 KASSERTMSG(!user || tf == lwp_trapframe(l), "tf %p vs %p", tf, 305 lwp_trapframe(l)); 306 307 /* 308 * Make sure the Program Counter is sane. We could fall foul of 309 * someone executing Thumb code, in which case the PC might not 310 * be word-aligned. This would cause a kernel alignment fault 311 * further down if we have to decode the current instruction. 312 */ 313 #ifdef THUMB_CODE 314 /* 315 * XXX: It would be nice to be able to support Thumb in the kernel 316 * at some point. 317 */ 318 if (__predict_false(!user && (tf->tf_pc & 3) != 0)) { 319 printf("\n%s: Misaligned Kernel-mode Program Counter\n", 320 __func__); 321 dab_fatal(tf, fsr, far, l, NULL); 322 } 323 #else 324 if (__predict_false((tf->tf_pc & 3) != 0)) { 325 if (user) { 326 /* 327 * Give the user an illegal instruction signal. 328 */ 329 /* Deliver a SIGILL to the process */ 330 KSI_INIT_TRAP(&ksi); 331 ksi.ksi_signo = SIGILL; 332 ksi.ksi_code = ILL_ILLOPC; 333 ksi.ksi_addr = (uint32_t *)(intptr_t) far; 334 ksi.ksi_trap = fsr; 335 goto do_trapsignal; 336 } 337 338 /* 339 * The kernel never executes Thumb code. 340 */ 341 printf("\n%s: Misaligned Kernel-mode Program Counter\n", 342 __func__); 343 dab_fatal(tf, fsr, far, l, NULL); 344 } 345 #endif 346 347 /* See if the CPU state needs to be fixed up */ 348 switch (data_abort_fixup(tf, fsr, far, l)) { 349 case ABORT_FIXUP_RETURN: 350 return; 351 case ABORT_FIXUP_FAILED: 352 /* Deliver a SIGILL to the process */ 353 KSI_INIT_TRAP(&ksi); 354 ksi.ksi_signo = SIGILL; 355 ksi.ksi_code = ILL_ILLOPC; 356 ksi.ksi_addr = (uint32_t *)(intptr_t) far; 357 ksi.ksi_trap = fsr; 358 goto do_trapsignal; 359 default: 360 break; 361 } 362 363 va = trunc_page((vaddr_t)far); 364 365 /* 366 * It is only a kernel address space fault iff: 367 * 1. user == 0 and 368 * 2. pcb_onfault not set or 369 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. 370 */ 371 if (!user && (va >= VM_MIN_KERNEL_ADDRESS || 372 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && 373 __predict_true((pcb->pcb_onfault == NULL || 374 (read_insn(tf->tf_pc, false) & 0x05200000) != 0x04200000))) { 375 map = kernel_map; 376 377 /* Was the fault due to the FPE ? */ 378 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { 379 KSI_INIT_TRAP(&ksi); 380 ksi.ksi_signo = SIGSEGV; 381 ksi.ksi_code = SEGV_ACCERR; 382 ksi.ksi_addr = (uint32_t *)(intptr_t) far; 383 ksi.ksi_trap = fsr; 384 385 /* 386 * Force exit via userret() 387 * This is necessary as the FPE is an extension to 388 * userland that actually runs in a priveledged mode 389 * but uses USR mode permissions for its accesses. 390 */ 391 user = true; 392 goto do_trapsignal; 393 } 394 } else { 395 map = &l->l_proc->p_vmspace->vm_map; 396 } 397 398 /* 399 * We need to know whether the page should be mapped as R or R/W. 400 * Before ARMv6, the MMU did not give us the info as to whether the 401 * fault was caused by a read or a write. 402 * 403 * However, we know that a permission fault can only be the result of 404 * a write to a read-only location, so we can deal with those quickly. 405 * 406 * Otherwise we need to disassemble the instruction responsible to 407 * determine if it was a write. 408 */ 409 if (CPU_IS_ARMV6_P() || CPU_IS_ARMV7_P()) { 410 ftype = (fsr & FAULT_WRITE) ? VM_PROT_WRITE : VM_PROT_READ; 411 } else if (IS_PERMISSION_FAULT(fsr)) { 412 ftype = VM_PROT_WRITE; 413 } else { 414 #ifdef THUMB_CODE 415 /* Fast track the ARM case. */ 416 if (__predict_false(tf->tf_spsr & PSR_T_bit)) { 417 u_int insn = read_thumb_insn(tf->tf_pc, user); 418 u_int insn_f8 = insn & 0xf800; 419 u_int insn_fe = insn & 0xfe00; 420 421 if (insn_f8 == 0x6000 || /* STR(1) */ 422 insn_f8 == 0x7000 || /* STRB(1) */ 423 insn_f8 == 0x8000 || /* STRH(1) */ 424 insn_f8 == 0x9000 || /* STR(3) */ 425 insn_f8 == 0xc000 || /* STM */ 426 insn_fe == 0x5000 || /* STR(2) */ 427 insn_fe == 0x5200 || /* STRH(2) */ 428 insn_fe == 0x5400) /* STRB(2) */ 429 ftype = VM_PROT_WRITE; 430 else 431 ftype = VM_PROT_READ; 432 } 433 else 434 #endif 435 { 436 u_int insn = read_insn(tf->tf_pc, user); 437 438 if (((insn & 0x0c100000) == 0x04000000) || /* STR[B] */ 439 ((insn & 0x0e1000b0) == 0x000000b0) || /* STR[HD]*/ 440 ((insn & 0x0a100000) == 0x08000000) || /* STM/CDT*/ 441 ((insn & 0x0f9000f0) == 0x01800090)) /* STREX[BDH] */ 442 ftype = VM_PROT_WRITE; 443 else if ((insn & 0x0fb00ff0) == 0x01000090)/* SWP */ 444 ftype = VM_PROT_READ | VM_PROT_WRITE; 445 else 446 ftype = VM_PROT_READ; 447 } 448 } 449 450 /* 451 * See if the fault is as a result of ref/mod emulation, 452 * or domain mismatch. 453 */ 454 #ifdef DEBUG 455 last_fault_code = fsr; 456 #endif 457 if (pmap_fault_fixup(map->pmap, va, ftype, user)) { 458 UVMHIST_LOG(maphist, " <- ref/mod emul", 0, 0, 0, 0); 459 goto out; 460 } 461 462 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 463 if (pcb->pcb_onfault) { 464 tf->tf_r0 = EINVAL; 465 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 466 return; 467 } 468 printf("\nNon-emulated page fault with intr_depth > 0\n"); 469 dab_fatal(tf, fsr, far, l, NULL); 470 } 471 472 #ifdef PMAP_FAULTINFO 473 struct pcb_faultinfo * const pfi = &pcb->pcb_faultinfo; 474 struct proc * const p = curproc; 475 476 if (p->p_pid == pfi->pfi_lastpid && va == pfi->pfi_faultaddr) { 477 if (++pfi->pfi_repeats > 4) { 478 tlb_asid_t asid = tlb_get_asid(); 479 pt_entry_t *ptep = pfi->pfi_faultptep; 480 481 printf("%s: fault #%u (%x/%s) for %#" PRIxVADDR 482 "(%#x) at pc %#" PRIxREGISTER " curpid=%u/%u " 483 "ptep@%p=%#" PRIxPTE ")\n", __func__, 484 pfi->pfi_repeats, fsr & FAULT_TYPE_MASK, 485 data_aborts[fsr & FAULT_TYPE_MASK].desc, va, 486 far, tf->tf_pc, map->pmap->pm_pai[0].pai_asid, 487 asid, ptep, ptep ? *ptep : 0); 488 cpu_Debugger(); 489 } 490 } else { 491 pfi->pfi_lastpid = p->p_pid; 492 pfi->pfi_faultaddr = va; 493 pfi->pfi_repeats = 0; 494 pfi->pfi_faultptep = NULL; 495 pfi->pfi_faulttype = fsr & FAULT_TYPE_MASK; 496 } 497 #endif /* PMAP_FAULTINFO */ 498 499 onfault = pcb->pcb_onfault; 500 pcb->pcb_onfault = NULL; 501 error = uvm_fault(map, va, ftype); 502 pcb->pcb_onfault = onfault; 503 504 if (__predict_true(error == 0)) { 505 if (user) 506 uvm_grow(l->l_proc, va); /* Record any stack growth */ 507 UVMHIST_LOG(maphist, " <- uvm", 0, 0, 0, 0); 508 goto out; 509 } 510 511 if (user == 0) { 512 if (pcb->pcb_onfault) { 513 tf->tf_r0 = error; 514 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 515 return; 516 } 517 518 printf("\nuvm_fault(%p, %lx, %x) -> %x\n", map, va, ftype, 519 error); 520 dab_fatal(tf, fsr, far, l, NULL); 521 } 522 523 KSI_INIT_TRAP(&ksi); 524 525 switch (error) { 526 case ENOMEM: 527 printf("UVM: pid %d (%s), uid %d killed: " 528 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 529 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 530 ksi.ksi_signo = SIGKILL; 531 break; 532 case EACCES: 533 ksi.ksi_signo = SIGSEGV; 534 ksi.ksi_code = SEGV_ACCERR; 535 break; 536 case EINVAL: 537 ksi.ksi_signo = SIGBUS; 538 ksi.ksi_code = BUS_ADRERR; 539 break; 540 default: 541 ksi.ksi_signo = SIGSEGV; 542 ksi.ksi_code = SEGV_MAPERR; 543 break; 544 } 545 ksi.ksi_addr = (uint32_t *)(intptr_t) far; 546 ksi.ksi_trap = fsr; 547 UVMHIST_LOG(maphist, " <- error (%jd)", error, 0, 0, 0); 548 549 do_trapsignal: 550 call_trapsignal(l, tf, &ksi); 551 out: 552 /* If returning to user mode, make sure to invoke userret() */ 553 if (user) 554 userret(l); 555 } 556 557 /* 558 * dab_fatal() handles the following data aborts: 559 * 560 * FAULT_WRTBUF_0 - Vector Exception 561 * FAULT_WRTBUF_1 - Terminal Exception 562 * 563 * We should never see these on a properly functioning system. 564 * 565 * This function is also called by the other handlers if they 566 * detect a fatal problem. 567 * 568 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 569 */ 570 static int 571 dab_fatal(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 572 { 573 const char * const mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 574 575 if (l != NULL) { 576 printf("Fatal %s mode data abort: '%s'\n", mode, 577 data_aborts[fsr & FAULT_TYPE_MASK].desc); 578 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 579 if ((fsr & FAULT_IMPRECISE) == 0) 580 printf("%08x, ", far); 581 else 582 printf("Invalid, "); 583 printf("spsr=%08x\n", tf->tf_spsr); 584 } else { 585 printf("Fatal %s mode prefetch abort at 0x%08x\n", 586 mode, tf->tf_pc); 587 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 588 } 589 590 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 591 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 592 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 593 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 594 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 595 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 596 printf("r12=%08x, ", tf->tf_r12); 597 598 if (TRAP_USERMODE(tf)) 599 printf("usp=%08x, ulr=%08x", 600 tf->tf_usr_sp, tf->tf_usr_lr); 601 else 602 printf("ssp=%08x, slr=%08x", 603 tf->tf_svc_sp, tf->tf_svc_lr); 604 printf(", pc =%08x\n\n", tf->tf_pc); 605 606 #if defined(DDB) || defined(KGDB) 607 kdb_trap(T_FAULT, tf); 608 #endif 609 panic("Fatal abort"); 610 /*NOTREACHED*/ 611 } 612 613 /* 614 * dab_align() handles the following data aborts: 615 * 616 * FAULT_ALIGN_0 - Alignment fault 617 * FAULT_ALIGN_0 - Alignment fault 618 * 619 * These faults are fatal if they happen in kernel mode. Otherwise, we 620 * deliver a bus error to the process. 621 */ 622 static int 623 dab_align(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, ksiginfo_t *ksi) 624 { 625 /* Alignment faults are always fatal if they occur in kernel mode */ 626 if (!TRAP_USERMODE(tf)) 627 dab_fatal(tf, fsr, far, l, NULL); 628 629 /* pcb_onfault *must* be NULL at this point */ 630 KDASSERT(((struct pcb *)lwp_getpcb(l))->pcb_onfault == NULL); 631 632 /* See if the CPU state needs to be fixed up */ 633 (void) data_abort_fixup(tf, fsr, far, l); 634 635 /* Deliver a bus error signal to the process */ 636 KSI_INIT_TRAP(ksi); 637 ksi->ksi_signo = SIGBUS; 638 ksi->ksi_code = BUS_ADRALN; 639 ksi->ksi_addr = (uint32_t *)(intptr_t)far; 640 ksi->ksi_trap = fsr; 641 642 KASSERTMSG(tf == lwp_trapframe(l), "tf %p vs %p", tf, lwp_trapframe(l)); 643 644 return 1; 645 } 646 647 /* 648 * dab_buserr() handles the following data aborts: 649 * 650 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 651 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 652 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 653 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 654 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 655 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 656 * 657 * If pcb_onfault is set, flag the fault and return to the handler. 658 * If the fault occurred in user mode, give the process a SIGBUS. 659 * 660 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 661 * can be flagged as imprecise in the FSR. This causes a real headache 662 * since some of the machine state is lost. In this case, tf->tf_pc 663 * may not actually point to the offending instruction. In fact, if 664 * we've taken a double abort fault, it generally points somewhere near 665 * the top of "data_abort_entry" in exception.S. 666 * 667 * In all other cases, these data aborts are considered fatal. 668 */ 669 static int 670 dab_buserr(trapframe_t *tf, u_int fsr, u_int far, struct lwp *l, 671 ksiginfo_t *ksi) 672 { 673 struct pcb *pcb = lwp_getpcb(l); 674 675 #ifdef __XSCALE__ 676 if ((fsr & FAULT_IMPRECISE) != 0 && 677 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 678 /* 679 * Oops, an imprecise, double abort fault. We've lost the 680 * r14_abt/spsr_abt values corresponding to the original 681 * abort, and the spsr saved in the trapframe indicates 682 * ABT mode. 683 */ 684 tf->tf_spsr &= ~PSR_MODE; 685 686 /* 687 * We use a simple heuristic to determine if the double abort 688 * happened as a result of a kernel or user mode access. 689 * If the current trapframe is at the top of the kernel stack, 690 * the fault _must_ have come from user mode. 691 */ 692 if (tf != ((trapframe_t *)pcb->pcb_ksp) - 1) { 693 /* 694 * Kernel mode. We're either about to die a 695 * spectacular death, or pcb_onfault will come 696 * to our rescue. Either way, the current value 697 * of tf->tf_pc is irrelevant. 698 */ 699 tf->tf_spsr |= PSR_SVC32_MODE; 700 if (pcb->pcb_onfault == NULL) 701 printf("\nKernel mode double abort!\n"); 702 } else { 703 /* 704 * User mode. We've lost the program counter at the 705 * time of the fault (not that it was accurate anyway; 706 * it's not called an imprecise fault for nothing). 707 * About all we can do is copy r14_usr to tf_pc and 708 * hope for the best. The process is about to get a 709 * SIGBUS, so it's probably history anyway. 710 */ 711 tf->tf_spsr |= PSR_USR32_MODE; 712 tf->tf_pc = tf->tf_usr_lr; 713 #ifdef THUMB_CODE 714 tf->tf_spsr &= ~PSR_T_bit; 715 if (tf->tf_usr_lr & 1) 716 tf->tf_spsr |= PSR_T_bit; 717 #endif 718 } 719 } 720 721 /* FAR is invalid for imprecise exceptions */ 722 if ((fsr & FAULT_IMPRECISE) != 0) 723 far = 0; 724 #endif /* __XSCALE__ */ 725 726 if (pcb->pcb_onfault) { 727 KDASSERT(TRAP_USERMODE(tf) == 0); 728 tf->tf_r0 = EFAULT; 729 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 730 return 0; 731 } 732 733 /* See if the CPU state needs to be fixed up */ 734 (void) data_abort_fixup(tf, fsr, far, l); 735 736 /* 737 * At this point, if the fault happened in kernel mode, we're toast 738 */ 739 if (!TRAP_USERMODE(tf)) 740 dab_fatal(tf, fsr, far, l, NULL); 741 742 /* Deliver a bus error signal to the process */ 743 KSI_INIT_TRAP(ksi); 744 ksi->ksi_signo = SIGBUS; 745 ksi->ksi_code = BUS_ADRERR; 746 ksi->ksi_addr = (uint32_t *)(intptr_t)far; 747 ksi->ksi_trap = fsr; 748 749 KASSERTMSG(tf == lwp_trapframe(l), "tf %p vs %p", tf, lwp_trapframe(l)); 750 751 return 1; 752 } 753 754 static inline int 755 prefetch_abort_fixup(trapframe_t *tf) 756 { 757 #ifdef CPU_ABORT_FIXUP_REQUIRED 758 int error; 759 760 /* Call the CPU specific prefetch abort fixup routine */ 761 error = cpu_prefetchabt_fixup(tf); 762 if (__predict_true(error != ABORT_FIXUP_FAILED)) 763 return error; 764 765 /* 766 * Oops, couldn't fix up the instruction 767 */ 768 printf("%s: fixup for %s mode prefetch abort failed.\n", __func__, 769 TRAP_USERMODE(tf) ? "user" : "kernel"); 770 #ifdef THUMB_CODE 771 if (tf->tf_spsr & PSR_T_bit) { 772 printf("pc = 0x%08x, opcode 0x%04x, 0x%04x, insn = ", 773 tf->tf_pc, *((uint16 *)(tf->tf_pc & ~1)), 774 *((uint16 *)((tf->tf_pc + 2) & ~1))); 775 } 776 else 777 #endif 778 { 779 printf("pc = 0x%08x, opcode 0x%08x, insn = ", tf->tf_pc, 780 *((u_int *)tf->tf_pc)); 781 } 782 disassemble(tf->tf_pc); 783 784 /* Die now if this happened in kernel mode */ 785 if (!TRAP_USERMODE(tf)) 786 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 787 788 return error; 789 #else 790 return ABORT_FIXUP_OK; 791 #endif /* CPU_ABORT_FIXUP_REQUIRED */ 792 } 793 794 /* 795 * void prefetch_abort_handler(trapframe_t *tf) 796 * 797 * Abort handler called when instruction execution occurs at 798 * a non existent or restricted (access permissions) memory page. 799 * If the address is invalid and we were in SVC mode then panic as 800 * the kernel should never prefetch abort. 801 * If the address is invalid and the page is mapped then the user process 802 * does no have read permission so send it a signal. 803 * Otherwise fault the page in and try again. 804 */ 805 void 806 prefetch_abort_handler(trapframe_t *tf) 807 { 808 struct lwp *l; 809 struct pcb *pcb __diagused; 810 struct vm_map *map; 811 vaddr_t fault_pc, va; 812 ksiginfo_t ksi; 813 int error, user; 814 815 UVMHIST_FUNC(__func__); 816 UVMHIST_CALLED(maphist); 817 818 /* Update vmmeter statistics */ 819 curcpu()->ci_data.cpu_ntrap++; 820 821 l = curlwp; 822 pcb = lwp_getpcb(l); 823 824 if ((user = TRAP_USERMODE(tf)) != 0) 825 LWP_CACHE_CREDS(l, l->l_proc); 826 827 /* 828 * Enable IRQ's (disabled by the abort) This always comes 829 * from user mode so we know interrupts were not disabled. 830 * But we check anyway. 831 */ 832 KASSERT(!TRAP_USERMODE(tf) || VALID_R15_PSR(tf->tf_pc, tf->tf_spsr)); 833 #ifdef __NO_FIQ 834 if (__predict_true((tf->tf_spsr & I32_bit) != I32_bit)) 835 restore_interrupts(tf->tf_spsr & IF32_bits); 836 #else 837 if (__predict_true((tf->tf_spsr & IF32_bits) != IF32_bits)) 838 restore_interrupts(tf->tf_spsr & IF32_bits); 839 #endif 840 841 /* See if the CPU state needs to be fixed up */ 842 switch (prefetch_abort_fixup(tf)) { 843 case ABORT_FIXUP_RETURN: 844 KASSERT(!TRAP_USERMODE(tf) || VALID_R15_PSR(tf->tf_pc, tf->tf_spsr)); 845 return; 846 case ABORT_FIXUP_FAILED: 847 /* Deliver a SIGILL to the process */ 848 KSI_INIT_TRAP(&ksi); 849 ksi.ksi_signo = SIGILL; 850 ksi.ksi_code = ILL_ILLOPC; 851 ksi.ksi_addr = (uint32_t *)(intptr_t) tf->tf_pc; 852 KASSERTMSG(tf == lwp_trapframe(l), "tf %p vs %p", tf, 853 lwp_trapframe(l)); 854 goto do_trapsignal; 855 default: 856 break; 857 } 858 859 /* Prefetch aborts cannot happen in kernel mode */ 860 if (__predict_false(!user)) 861 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 862 863 /* Get fault address */ 864 fault_pc = tf->tf_pc; 865 KASSERTMSG(tf == lwp_trapframe(l), "tf %p vs %p", tf, lwp_trapframe(l)); 866 UVMHIST_LOG(maphist, " (pc=%#jx, l=%#jx, tf=%#jx)", 867 fault_pc, (uintptr_t)l, (uintptr_t)tf, 0); 868 869 #ifdef THUMB_CODE 870 recheck: 871 #endif 872 /* Ok validate the address, can only execute in USER space */ 873 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 874 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 875 KSI_INIT_TRAP(&ksi); 876 ksi.ksi_signo = SIGSEGV; 877 ksi.ksi_code = SEGV_ACCERR; 878 ksi.ksi_addr = (uint32_t *)(intptr_t) fault_pc; 879 ksi.ksi_trap = fault_pc; 880 goto do_trapsignal; 881 } 882 883 map = &l->l_proc->p_vmspace->vm_map; 884 va = trunc_page(fault_pc); 885 886 /* 887 * See if the pmap can handle this fault on its own... 888 */ 889 #ifdef DEBUG 890 last_fault_code = -1; 891 #endif 892 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ|VM_PROT_EXECUTE, 1)) { 893 UVMHIST_LOG (maphist, " <- emulated", 0, 0, 0, 0); 894 goto out; 895 } 896 897 #ifdef DIAGNOSTIC 898 if (__predict_false(curcpu()->ci_intr_depth > 0)) { 899 printf("\nNon-emulated prefetch abort with intr_depth > 0\n"); 900 dab_fatal(tf, 0, tf->tf_pc, NULL, NULL); 901 } 902 #endif 903 904 KASSERT(pcb->pcb_onfault == NULL); 905 error = uvm_fault(map, va, VM_PROT_READ|VM_PROT_EXECUTE); 906 907 if (__predict_true(error == 0)) { 908 UVMHIST_LOG (maphist, " <- uvm", 0, 0, 0, 0); 909 goto out; 910 } 911 KSI_INIT_TRAP(&ksi); 912 913 UVMHIST_LOG (maphist, " <- fatal (%jd)", error, 0, 0, 0); 914 915 if (error == ENOMEM) { 916 printf("UVM: pid %d (%s), uid %d killed: " 917 "out of swap\n", l->l_proc->p_pid, l->l_proc->p_comm, 918 l->l_cred ? kauth_cred_geteuid(l->l_cred) : -1); 919 ksi.ksi_signo = SIGKILL; 920 } else 921 ksi.ksi_signo = SIGSEGV; 922 923 ksi.ksi_code = SEGV_MAPERR; 924 ksi.ksi_addr = (uint32_t *)(intptr_t) fault_pc; 925 ksi.ksi_trap = fault_pc; 926 927 do_trapsignal: 928 call_trapsignal(l, tf, &ksi); 929 930 out: 931 932 #ifdef THUMB_CODE 933 #define THUMB_32BIT(hi) (((hi) & 0xe000) == 0xe000 && ((hi) & 0x1800)) 934 /* thumb-32 instruction was located on page boundary? */ 935 if ((tf->tf_spsr & PSR_T_bit) && 936 ((fault_pc & PAGE_MASK) == (PAGE_SIZE - THUMB_INSN_SIZE)) && 937 THUMB_32BIT(*(uint16_t *)tf->tf_pc)) { 938 fault_pc = tf->tf_pc + THUMB_INSN_SIZE; 939 goto recheck; 940 } 941 #endif /* THUMB_CODE */ 942 943 KASSERT(!TRAP_USERMODE(tf) || VALID_R15_PSR(tf->tf_pc, tf->tf_spsr)); 944 userret(l); 945 } 946 947 /* 948 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 949 * If the read succeeds, the value is written to 'rptr' and zero is returned. 950 * Else, return EFAULT. 951 */ 952 int 953 badaddr_read(void *addr, size_t size, void *rptr) 954 { 955 extern int badaddr_read_1(const uint8_t *, uint8_t *); 956 extern int badaddr_read_2(const uint16_t *, uint16_t *); 957 extern int badaddr_read_4(const uint32_t *, uint32_t *); 958 union { 959 uint8_t v1; 960 uint16_t v2; 961 uint32_t v4; 962 } u; 963 int rv, s; 964 965 cpu_drain_writebuf(); 966 967 s = splhigh(); 968 969 /* Read from the test address. */ 970 switch (size) { 971 case sizeof(uint8_t): 972 rv = badaddr_read_1(addr, &u.v1); 973 if (rv == 0 && rptr) 974 *(uint8_t *) rptr = u.v1; 975 break; 976 977 case sizeof(uint16_t): 978 rv = badaddr_read_2(addr, &u.v2); 979 if (rv == 0 && rptr) 980 *(uint16_t *) rptr = u.v2; 981 break; 982 983 case sizeof(uint32_t): 984 rv = badaddr_read_4(addr, &u.v4); 985 if (rv == 0 && rptr) 986 *(uint32_t *) rptr = u.v4; 987 break; 988 989 default: 990 panic("%s: invalid size (%zu)", __func__, size); 991 } 992 993 splx(s); 994 995 /* Return EFAULT if the address was invalid, else zero */ 996 return rv; 997 } 998