trap.c revision 266311
1/* $NetBSD: fault.c,v 1.45 2003/11/20 14:44:36 scw Exp $ */ 2 3/*- 4 * Copyright 2004 Olivier Houchard 5 * Copyright 2003 Wasabi Systems, Inc. 6 * All rights reserved. 7 * 8 * Written by Steve C. Woodford for Wasabi Systems, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed for the NetBSD Project by 21 * Wasabi Systems, Inc. 22 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 23 * or promote products derived from this software without specific prior 24 * written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38/*- 39 * Copyright (c) 1994-1997 Mark Brinicombe. 40 * Copyright (c) 1994 Brini. 41 * All rights reserved. 42 * 43 * This code is derived from software written for Brini by Mark Brinicombe 44 * 45 * Redistribution and use in source and binary forms, with or without 46 * modification, are permitted provided that the following conditions 47 * are met: 48 * 1. Redistributions of source code must retain the above copyright 49 * notice, this list of conditions and the following disclaimer. 50 * 2. Redistributions in binary form must reproduce the above copyright 51 * notice, this list of conditions and the following disclaimer in the 52 * documentation and/or other materials provided with the distribution. 53 * 3. All advertising materials mentioning features or use of this software 54 * must display the following acknowledgement: 55 * This product includes software developed by Brini. 56 * 4. The name of the company nor the name of the author may be used to 57 * endorse or promote products derived from this software without specific 58 * prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED 61 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 62 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 63 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 64 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 65 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 66 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * RiscBSD kernel project 73 * 74 * fault.c 75 * 76 * Fault handlers 77 * 78 * Created : 28/11/94 79 */ 80 81 82#include "opt_ktrace.h" 83 84#include <sys/cdefs.h> 85__FBSDID("$FreeBSD: stable/10/sys/arm/arm/trap.c 266311 2014-05-17 13:53:38Z ian $"); 86 87#include <sys/param.h> 88#include <sys/bus.h> 89#include <sys/systm.h> 90#include <sys/proc.h> 91#include <sys/kernel.h> 92#include <sys/lock.h> 93#include <sys/mutex.h> 94#include <sys/syscall.h> 95#include <sys/sysent.h> 96#include <sys/signalvar.h> 97#include <sys/ktr.h> 98#ifdef KTRACE 99#include <sys/uio.h> 100#include <sys/ktrace.h> 101#endif 102#include <sys/ptrace.h> 103#include <sys/pioctl.h> 104 105#include <vm/vm.h> 106#include <vm/pmap.h> 107#include <vm/vm_kern.h> 108#include <vm/vm_map.h> 109#include <vm/vm_extern.h> 110 111#include <machine/armreg.h> 112#include <machine/cpuconf.h> 113#include <machine/vmparam.h> 114#include <machine/frame.h> 115#include <machine/cpu.h> 116#include <machine/intr.h> 117#include <machine/pcb.h> 118#include <machine/proc.h> 119#include <machine/swi.h> 120 121#include <security/audit/audit.h> 122 123#ifdef KDB 124#include <sys/kdb.h> 125#endif 126 127 128void swi_handler(struct trapframe *); 129 130#include <machine/disassem.h> 131#include <machine/machdep.h> 132 133extern char fusubailout[]; 134 135#ifdef DEBUG 136int last_fault_code; /* For the benefit of pmap_fault_fixup() */ 137#endif 138 139struct ksig { 140 int signb; 141 u_long code; 142}; 143struct data_abort { 144 int (*func)(struct trapframe *, u_int, u_int, struct thread *, 145 struct ksig *); 146 const char *desc; 147}; 148 149static int dab_fatal(struct trapframe *, u_int, u_int, struct thread *, 150 struct ksig *); 151static int dab_align(struct trapframe *, u_int, u_int, struct thread *, 152 struct ksig *); 153static int dab_buserr(struct trapframe *, u_int, u_int, struct thread *, 154 struct ksig *); 155 156static const struct data_abort data_aborts[] = { 157 {dab_fatal, "Vector Exception"}, 158 {dab_align, "Alignment Fault 1"}, 159 {dab_fatal, "Terminal Exception"}, 160 {dab_align, "Alignment Fault 3"}, 161 {dab_buserr, "External Linefetch Abort (S)"}, 162 {NULL, "Translation Fault (S)"}, 163#if (ARM_MMU_V6 + ARM_MMU_V7) != 0 164 {NULL, "Translation Flag Fault"}, 165#else 166 {dab_buserr, "External Linefetch Abort (P)"}, 167#endif 168 {NULL, "Translation Fault (P)"}, 169 {dab_buserr, "External Non-Linefetch Abort (S)"}, 170 {NULL, "Domain Fault (S)"}, 171 {dab_buserr, "External Non-Linefetch Abort (P)"}, 172 {NULL, "Domain Fault (P)"}, 173 {dab_buserr, "External Translation Abort (L1)"}, 174 {NULL, "Permission Fault (S)"}, 175 {dab_buserr, "External Translation Abort (L2)"}, 176 {NULL, "Permission Fault (P)"} 177}; 178 179/* Determine if a fault came from user mode */ 180#define TRAP_USERMODE(tf) ((tf->tf_spsr & PSR_MODE) == PSR_USR32_MODE) 181 182/* Determine if 'x' is a permission fault */ 183#define IS_PERMISSION_FAULT(x) \ 184 (((1 << ((x) & FAULT_TYPE_MASK)) & \ 185 ((1 << FAULT_PERM_P) | (1 << FAULT_PERM_S))) != 0) 186 187static __inline void 188call_trapsignal(struct thread *td, int sig, u_long code) 189{ 190 ksiginfo_t ksi; 191 192 ksiginfo_init_trap(&ksi); 193 ksi.ksi_signo = sig; 194 ksi.ksi_code = (int)code; 195 trapsignal(td, &ksi); 196} 197 198void 199data_abort_handler(struct trapframe *tf) 200{ 201 struct vm_map *map; 202 struct pcb *pcb; 203 struct thread *td; 204 u_int user, far, fsr; 205 vm_prot_t ftype; 206 void *onfault; 207 vm_offset_t va; 208 int error = 0; 209 struct ksig ksig; 210 struct proc *p; 211 212 213 /* Grab FAR/FSR before enabling interrupts */ 214 far = cpu_faultaddress(); 215 fsr = cpu_faultstatus(); 216#if 0 217 printf("data abort: fault address=%p (from pc=%p lr=%p)\n", 218 (void*)far, (void*)tf->tf_pc, (void*)tf->tf_svc_lr); 219#endif 220 221 /* Update vmmeter statistics */ 222#if 0 223 vmexp.traps++; 224#endif 225 226 td = curthread; 227 p = td->td_proc; 228 229 PCPU_INC(cnt.v_trap); 230 /* Data abort came from user mode? */ 231 user = TRAP_USERMODE(tf); 232 233 if (user) { 234 td->td_pticks = 0; 235 td->td_frame = tf; 236 if (td->td_ucred != td->td_proc->p_ucred) 237 cred_update_thread(td); 238 239 } 240 /* Grab the current pcb */ 241 pcb = td->td_pcb; 242 /* Re-enable interrupts if they were enabled previously */ 243 if (td->td_md.md_spinlock_count == 0) { 244 if (__predict_true(tf->tf_spsr & I32_bit) == 0) 245 enable_interrupts(I32_bit); 246 if (__predict_true(tf->tf_spsr & F32_bit) == 0) 247 enable_interrupts(F32_bit); 248 } 249 250 251 /* Invoke the appropriate handler, if necessary */ 252 if (__predict_false(data_aborts[fsr & FAULT_TYPE_MASK].func != NULL)) { 253 if ((data_aborts[fsr & FAULT_TYPE_MASK].func)(tf, fsr, far, 254 td, &ksig)) { 255 goto do_trapsignal; 256 } 257 goto out; 258 } 259 260 /* 261 * At this point, we're dealing with one of the following data aborts: 262 * 263 * FAULT_TRANS_S - Translation -- Section 264 * FAULT_TRANS_P - Translation -- Page 265 * FAULT_DOMAIN_S - Domain -- Section 266 * FAULT_DOMAIN_P - Domain -- Page 267 * FAULT_PERM_S - Permission -- Section 268 * FAULT_PERM_P - Permission -- Page 269 * 270 * These are the main virtual memory-related faults signalled by 271 * the MMU. 272 */ 273 274 /* fusubailout is used by [fs]uswintr to avoid page faulting */ 275 if (__predict_false(pcb->pcb_onfault == fusubailout)) { 276 tf->tf_r0 = EFAULT; 277 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 278 return; 279 } 280 281 /* 282 * Make sure the Program Counter is sane. We could fall foul of 283 * someone executing Thumb code, in which case the PC might not 284 * be word-aligned. This would cause a kernel alignment fault 285 * further down if we have to decode the current instruction. 286 * XXX: It would be nice to be able to support Thumb at some point. 287 */ 288 if (__predict_false((tf->tf_pc & 3) != 0)) { 289 if (user) { 290 /* 291 * Give the user an illegal instruction signal. 292 */ 293 /* Deliver a SIGILL to the process */ 294 ksig.signb = SIGILL; 295 ksig.code = 0; 296 goto do_trapsignal; 297 } 298 299 /* 300 * The kernel never executes Thumb code. 301 */ 302 printf("\ndata_abort_fault: Misaligned Kernel-mode " 303 "Program Counter\n"); 304 dab_fatal(tf, fsr, far, td, &ksig); 305 } 306 307 va = trunc_page((vm_offset_t)far); 308 309 /* 310 * It is only a kernel address space fault iff: 311 * 1. user == 0 and 312 * 2. pcb_onfault not set or 313 * 3. pcb_onfault set and not LDRT/LDRBT/STRT/STRBT instruction. 314 */ 315 if (user == 0 && (va >= VM_MIN_KERNEL_ADDRESS || 316 (va < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW)) && 317 __predict_true((pcb->pcb_onfault == NULL || 318 (ReadWord(tf->tf_pc) & 0x05200000) != 0x04200000))) { 319 map = kernel_map; 320 321 /* Was the fault due to the FPE/IPKDB ? */ 322 if (__predict_false((tf->tf_spsr & PSR_MODE)==PSR_UND32_MODE)) { 323 324 /* 325 * Force exit via userret() 326 * This is necessary as the FPE is an extension to 327 * userland that actually runs in a priveledged mode 328 * but uses USR mode permissions for its accesses. 329 */ 330 user = 1; 331 ksig.signb = SIGSEGV; 332 ksig.code = 0; 333 goto do_trapsignal; 334 } 335 } else { 336 map = &td->td_proc->p_vmspace->vm_map; 337 } 338 339 /* 340 * We need to know whether the page should be mapped as R or R/W. On 341 * armv6 and later the fault status register indicates whether the 342 * access was a read or write. Prior to armv6, we know that a 343 * permission fault can only be the result of a write to a read-only 344 * location, so we can deal with those quickly. Otherwise we need to 345 * disassemble the faulting instruction to determine if it was a write. 346 */ 347#if ARM_ARCH_6 || ARM_ARCH_7A 348 ftype = (fsr & FAULT_WNR) ? VM_PROT_READ | VM_PROT_WRITE : VM_PROT_READ; 349#else 350 if (IS_PERMISSION_FAULT(fsr)) 351 ftype = VM_PROT_WRITE; 352 else { 353 u_int insn = ReadWord(tf->tf_pc); 354 355 if (((insn & 0x0c100000) == 0x04000000) || /* STR/STRB */ 356 ((insn & 0x0e1000b0) == 0x000000b0) || /* STRH/STRD */ 357 ((insn & 0x0a100000) == 0x08000000)) { /* STM/CDT */ 358 ftype = VM_PROT_WRITE; 359 } else { 360 if ((insn & 0x0fb00ff0) == 0x01000090) /* SWP */ 361 ftype = VM_PROT_READ | VM_PROT_WRITE; 362 else 363 ftype = VM_PROT_READ; 364 } 365 } 366#endif 367 368 /* 369 * See if the fault is as a result of ref/mod emulation, 370 * or domain mismatch. 371 */ 372#ifdef DEBUG 373 last_fault_code = fsr; 374#endif 375 if (pmap_fault_fixup(vmspace_pmap(td->td_proc->p_vmspace), va, ftype, 376 user)) { 377 goto out; 378 } 379 380 onfault = pcb->pcb_onfault; 381 pcb->pcb_onfault = NULL; 382 if (map != kernel_map) { 383 PROC_LOCK(p); 384 p->p_lock++; 385 PROC_UNLOCK(p); 386 } 387 error = vm_fault(map, va, ftype, VM_FAULT_NORMAL); 388 pcb->pcb_onfault = onfault; 389 390 if (map != kernel_map) { 391 PROC_LOCK(p); 392 p->p_lock--; 393 PROC_UNLOCK(p); 394 } 395 if (__predict_true(error == 0)) 396 goto out; 397 if (user == 0) { 398 if (pcb->pcb_onfault) { 399 tf->tf_r0 = error; 400 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 401 return; 402 } 403 404 printf("\nvm_fault(%p, %x, %x, 0) -> %x\n", map, va, ftype, 405 error); 406 dab_fatal(tf, fsr, far, td, &ksig); 407 } 408 409 410 if (error == ENOMEM) { 411 printf("VM: pid %d (%s), uid %d killed: " 412 "out of swap\n", td->td_proc->p_pid, td->td_name, 413 (td->td_proc->p_ucred) ? 414 td->td_proc->p_ucred->cr_uid : -1); 415 ksig.signb = SIGKILL; 416 } else { 417 ksig.signb = SIGSEGV; 418 } 419 ksig.code = 0; 420do_trapsignal: 421 call_trapsignal(td, ksig.signb, ksig.code); 422out: 423 /* If returning to user mode, make sure to invoke userret() */ 424 if (user) 425 userret(td, tf); 426} 427 428/* 429 * dab_fatal() handles the following data aborts: 430 * 431 * FAULT_WRTBUF_0 - Vector Exception 432 * FAULT_WRTBUF_1 - Terminal Exception 433 * 434 * We should never see these on a properly functioning system. 435 * 436 * This function is also called by the other handlers if they 437 * detect a fatal problem. 438 * 439 * Note: If 'l' is NULL, we assume we're dealing with a prefetch abort. 440 */ 441static int 442dab_fatal(struct trapframe *tf, u_int fsr, u_int far, struct thread *td, 443 struct ksig *ksig) 444{ 445 const char *mode; 446 447 mode = TRAP_USERMODE(tf) ? "user" : "kernel"; 448 449 disable_interrupts(I32_bit|F32_bit); 450 if (td != NULL) { 451 printf("Fatal %s mode data abort: '%s'\n", mode, 452 data_aborts[fsr & FAULT_TYPE_MASK].desc); 453 printf("trapframe: %p\nFSR=%08x, FAR=", tf, fsr); 454 if ((fsr & FAULT_IMPRECISE) == 0) 455 printf("%08x, ", far); 456 else 457 printf("Invalid, "); 458 printf("spsr=%08x\n", tf->tf_spsr); 459 } else { 460 printf("Fatal %s mode prefetch abort at 0x%08x\n", 461 mode, tf->tf_pc); 462 printf("trapframe: %p, spsr=%08x\n", tf, tf->tf_spsr); 463 } 464 465 printf("r0 =%08x, r1 =%08x, r2 =%08x, r3 =%08x\n", 466 tf->tf_r0, tf->tf_r1, tf->tf_r2, tf->tf_r3); 467 printf("r4 =%08x, r5 =%08x, r6 =%08x, r7 =%08x\n", 468 tf->tf_r4, tf->tf_r5, tf->tf_r6, tf->tf_r7); 469 printf("r8 =%08x, r9 =%08x, r10=%08x, r11=%08x\n", 470 tf->tf_r8, tf->tf_r9, tf->tf_r10, tf->tf_r11); 471 printf("r12=%08x, ", tf->tf_r12); 472 473 if (TRAP_USERMODE(tf)) 474 printf("usp=%08x, ulr=%08x", 475 tf->tf_usr_sp, tf->tf_usr_lr); 476 else 477 printf("ssp=%08x, slr=%08x", 478 tf->tf_svc_sp, tf->tf_svc_lr); 479 printf(", pc =%08x\n\n", tf->tf_pc); 480 481#ifdef KDB 482 if (debugger_on_panic || kdb_active) 483 if (kdb_trap(fsr, 0, tf)) 484 return (0); 485#endif 486 panic("Fatal abort"); 487 /*NOTREACHED*/ 488} 489 490/* 491 * dab_align() handles the following data aborts: 492 * 493 * FAULT_ALIGN_0 - Alignment fault 494 * FAULT_ALIGN_1 - Alignment fault 495 * 496 * These faults are fatal if they happen in kernel mode. Otherwise, we 497 * deliver a bus error to the process. 498 */ 499static int 500dab_align(struct trapframe *tf, u_int fsr, u_int far, struct thread *td, 501 struct ksig *ksig) 502{ 503 504 /* Alignment faults are always fatal if they occur in kernel mode */ 505 if (!TRAP_USERMODE(tf)) { 506 if (!td || !td->td_pcb->pcb_onfault) 507 dab_fatal(tf, fsr, far, td, ksig); 508 tf->tf_r0 = EFAULT; 509 tf->tf_pc = (int)td->td_pcb->pcb_onfault; 510 return (0); 511 } 512 513 /* pcb_onfault *must* be NULL at this point */ 514 515 /* Deliver a bus error signal to the process */ 516 ksig->code = 0; 517 ksig->signb = SIGBUS; 518 td->td_frame = tf; 519 520 return (1); 521} 522 523/* 524 * dab_buserr() handles the following data aborts: 525 * 526 * FAULT_BUSERR_0 - External Abort on Linefetch -- Section 527 * FAULT_BUSERR_1 - External Abort on Linefetch -- Page 528 * FAULT_BUSERR_2 - External Abort on Non-linefetch -- Section 529 * FAULT_BUSERR_3 - External Abort on Non-linefetch -- Page 530 * FAULT_BUSTRNL1 - External abort on Translation -- Level 1 531 * FAULT_BUSTRNL2 - External abort on Translation -- Level 2 532 * 533 * If pcb_onfault is set, flag the fault and return to the handler. 534 * If the fault occurred in user mode, give the process a SIGBUS. 535 * 536 * Note: On XScale, FAULT_BUSERR_0, FAULT_BUSERR_1, and FAULT_BUSERR_2 537 * can be flagged as imprecise in the FSR. This causes a real headache 538 * since some of the machine state is lost. In this case, tf->tf_pc 539 * may not actually point to the offending instruction. In fact, if 540 * we've taken a double abort fault, it generally points somewhere near 541 * the top of "data_abort_entry" in exception.S. 542 * 543 * In all other cases, these data aborts are considered fatal. 544 */ 545static int 546dab_buserr(struct trapframe *tf, u_int fsr, u_int far, struct thread *td, 547 struct ksig *ksig) 548{ 549 struct pcb *pcb = td->td_pcb; 550 551#ifdef __XSCALE__ 552 if ((fsr & FAULT_IMPRECISE) != 0 && 553 (tf->tf_spsr & PSR_MODE) == PSR_ABT32_MODE) { 554 /* 555 * Oops, an imprecise, double abort fault. We've lost the 556 * r14_abt/spsr_abt values corresponding to the original 557 * abort, and the spsr saved in the trapframe indicates 558 * ABT mode. 559 */ 560 tf->tf_spsr &= ~PSR_MODE; 561 562 /* 563 * We use a simple heuristic to determine if the double abort 564 * happened as a result of a kernel or user mode access. 565 * If the current trapframe is at the top of the kernel stack, 566 * the fault _must_ have come from user mode. 567 */ 568 if (tf != ((struct trapframe *)pcb->un_32.pcb32_sp) - 1) { 569 /* 570 * Kernel mode. We're either about to die a 571 * spectacular death, or pcb_onfault will come 572 * to our rescue. Either way, the current value 573 * of tf->tf_pc is irrelevant. 574 */ 575 tf->tf_spsr |= PSR_SVC32_MODE; 576 if (pcb->pcb_onfault == NULL) 577 printf("\nKernel mode double abort!\n"); 578 } else { 579 /* 580 * User mode. We've lost the program counter at the 581 * time of the fault (not that it was accurate anyway; 582 * it's not called an imprecise fault for nothing). 583 * About all we can do is copy r14_usr to tf_pc and 584 * hope for the best. The process is about to get a 585 * SIGBUS, so it's probably history anyway. 586 */ 587 tf->tf_spsr |= PSR_USR32_MODE; 588 tf->tf_pc = tf->tf_usr_lr; 589 } 590 } 591 592 /* FAR is invalid for imprecise exceptions */ 593 if ((fsr & FAULT_IMPRECISE) != 0) 594 far = 0; 595#endif /* __XSCALE__ */ 596 597 if (pcb->pcb_onfault) { 598 tf->tf_r0 = EFAULT; 599 tf->tf_pc = (register_t)(intptr_t) pcb->pcb_onfault; 600 return (0); 601 } 602 603 /* 604 * At this point, if the fault happened in kernel mode, we're toast 605 */ 606 if (!TRAP_USERMODE(tf)) 607 dab_fatal(tf, fsr, far, td, ksig); 608 609 /* Deliver a bus error signal to the process */ 610 ksig->signb = SIGBUS; 611 ksig->code = 0; 612 td->td_frame = tf; 613 614 return (1); 615} 616 617/* 618 * void prefetch_abort_handler(struct trapframe *tf) 619 * 620 * Abort handler called when instruction execution occurs at 621 * a non existent or restricted (access permissions) memory page. 622 * If the address is invalid and we were in SVC mode then panic as 623 * the kernel should never prefetch abort. 624 * If the address is invalid and the page is mapped then the user process 625 * does no have read permission so send it a signal. 626 * Otherwise fault the page in and try again. 627 */ 628void 629prefetch_abort_handler(struct trapframe *tf) 630{ 631 struct thread *td; 632 struct proc * p; 633 struct vm_map *map; 634 vm_offset_t fault_pc, va; 635 int error = 0; 636 struct ksig ksig; 637 638 639#if 0 640 /* Update vmmeter statistics */ 641 uvmexp.traps++; 642#endif 643#if 0 644 printf("prefetch abort handler: %p %p\n", (void*)tf->tf_pc, 645 (void*)tf->tf_usr_lr); 646#endif 647 648 td = curthread; 649 p = td->td_proc; 650 PCPU_INC(cnt.v_trap); 651 652 if (TRAP_USERMODE(tf)) { 653 td->td_frame = tf; 654 if (td->td_ucred != td->td_proc->p_ucred) 655 cred_update_thread(td); 656 } 657 fault_pc = tf->tf_pc; 658 if (td->td_md.md_spinlock_count == 0) { 659 if (__predict_true(tf->tf_spsr & I32_bit) == 0) 660 enable_interrupts(I32_bit); 661 if (__predict_true(tf->tf_spsr & F32_bit) == 0) 662 enable_interrupts(F32_bit); 663 } 664 665 /* Prefetch aborts cannot happen in kernel mode */ 666 if (__predict_false(!TRAP_USERMODE(tf))) 667 dab_fatal(tf, 0, tf->tf_pc, NULL, &ksig); 668 td->td_pticks = 0; 669 670 671 /* Ok validate the address, can only execute in USER space */ 672 if (__predict_false(fault_pc >= VM_MAXUSER_ADDRESS || 673 (fault_pc < VM_MIN_ADDRESS && vector_page == ARM_VECTORS_LOW))) { 674 ksig.signb = SIGSEGV; 675 ksig.code = 0; 676 goto do_trapsignal; 677 } 678 679 map = &td->td_proc->p_vmspace->vm_map; 680 va = trunc_page(fault_pc); 681 682 /* 683 * See if the pmap can handle this fault on its own... 684 */ 685#ifdef DEBUG 686 last_fault_code = -1; 687#endif 688 if (pmap_fault_fixup(map->pmap, va, VM_PROT_READ, 1)) 689 goto out; 690 691 if (map != kernel_map) { 692 PROC_LOCK(p); 693 p->p_lock++; 694 PROC_UNLOCK(p); 695 } 696 697 error = vm_fault(map, va, VM_PROT_READ | VM_PROT_EXECUTE, 698 VM_FAULT_NORMAL); 699 if (map != kernel_map) { 700 PROC_LOCK(p); 701 p->p_lock--; 702 PROC_UNLOCK(p); 703 } 704 705 if (__predict_true(error == 0)) 706 goto out; 707 708 if (error == ENOMEM) { 709 printf("VM: pid %d (%s), uid %d killed: " 710 "out of swap\n", td->td_proc->p_pid, td->td_name, 711 (td->td_proc->p_ucred) ? 712 td->td_proc->p_ucred->cr_uid : -1); 713 ksig.signb = SIGKILL; 714 } else { 715 ksig.signb = SIGSEGV; 716 } 717 ksig.code = 0; 718 719do_trapsignal: 720 call_trapsignal(td, ksig.signb, ksig.code); 721 722out: 723 userret(td, tf); 724 725} 726 727extern int badaddr_read_1(const uint8_t *, uint8_t *); 728extern int badaddr_read_2(const uint16_t *, uint16_t *); 729extern int badaddr_read_4(const uint32_t *, uint32_t *); 730/* 731 * Tentatively read an 8, 16, or 32-bit value from 'addr'. 732 * If the read succeeds, the value is written to 'rptr' and zero is returned. 733 * Else, return EFAULT. 734 */ 735int 736badaddr_read(void *addr, size_t size, void *rptr) 737{ 738 union { 739 uint8_t v1; 740 uint16_t v2; 741 uint32_t v4; 742 } u; 743 int rv; 744 745 cpu_drain_writebuf(); 746 747 /* Read from the test address. */ 748 switch (size) { 749 case sizeof(uint8_t): 750 rv = badaddr_read_1(addr, &u.v1); 751 if (rv == 0 && rptr) 752 *(uint8_t *) rptr = u.v1; 753 break; 754 755 case sizeof(uint16_t): 756 rv = badaddr_read_2(addr, &u.v2); 757 if (rv == 0 && rptr) 758 *(uint16_t *) rptr = u.v2; 759 break; 760 761 case sizeof(uint32_t): 762 rv = badaddr_read_4(addr, &u.v4); 763 if (rv == 0 && rptr) 764 *(uint32_t *) rptr = u.v4; 765 break; 766 767 default: 768 panic("badaddr: invalid size (%lu)", (u_long) size); 769 } 770 771 /* Return EFAULT if the address was invalid, else zero */ 772 return (rv); 773} 774 775int 776cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 777{ 778 struct proc *p; 779 register_t *ap; 780 int error; 781 782#ifdef __ARM_EABI__ 783 sa->code = td->td_frame->tf_r7; 784#else 785 sa->code = sa->insn & 0x000fffff; 786#endif 787 ap = &td->td_frame->tf_r0; 788 if (sa->code == SYS_syscall) { 789 sa->code = *ap++; 790 sa->nap--; 791 } else if (sa->code == SYS___syscall) { 792 sa->code = ap[_QUAD_LOWWORD]; 793 sa->nap -= 2; 794 ap += 2; 795 } 796 p = td->td_proc; 797 if (p->p_sysent->sv_mask) 798 sa->code &= p->p_sysent->sv_mask; 799 if (sa->code >= p->p_sysent->sv_size) 800 sa->callp = &p->p_sysent->sv_table[0]; 801 else 802 sa->callp = &p->p_sysent->sv_table[sa->code]; 803 sa->narg = sa->callp->sy_narg; 804 error = 0; 805 memcpy(sa->args, ap, sa->nap * sizeof(register_t)); 806 if (sa->narg > sa->nap) { 807 error = copyin((void *)td->td_frame->tf_usr_sp, sa->args + 808 sa->nap, (sa->narg - sa->nap) * sizeof(register_t)); 809 } 810 if (error == 0) { 811 td->td_retval[0] = 0; 812 td->td_retval[1] = 0; 813 } 814 return (error); 815} 816 817#include "../../kern/subr_syscall.c" 818 819static void 820syscall(struct thread *td, struct trapframe *frame) 821{ 822 struct syscall_args sa; 823 int error; 824 825#ifndef __ARM_EABI__ 826 sa.insn = *(uint32_t *)(frame->tf_pc - INSN_SIZE); 827 switch (sa.insn & SWI_OS_MASK) { 828 case 0: /* XXX: we need our own one. */ 829 break; 830 default: 831 call_trapsignal(td, SIGILL, 0); 832 userret(td, frame); 833 return; 834 } 835#endif 836 sa.nap = 4; 837 838 error = syscallenter(td, &sa); 839 KASSERT(error != 0 || td->td_ar == NULL, 840 ("returning from syscall with td_ar set!")); 841 syscallret(td, error, &sa); 842} 843 844void 845swi_handler(struct trapframe *frame) 846{ 847 struct thread *td = curthread; 848 849 td->td_frame = frame; 850 851 td->td_pticks = 0; 852 /* 853 * Make sure the program counter is correctly aligned so we 854 * don't take an alignment fault trying to read the opcode. 855 */ 856 if (__predict_false(((frame->tf_pc - INSN_SIZE) & 3) != 0)) { 857 call_trapsignal(td, SIGILL, 0); 858 userret(td, frame); 859 return; 860 } 861 /* 862 * Enable interrupts if they were enabled before the exception. 863 * Since all syscalls *should* come from user mode it will always 864 * be safe to enable them, but check anyway. 865 */ 866 if (td->td_md.md_spinlock_count == 0) { 867 if (__predict_true(frame->tf_spsr & I32_bit) == 0) 868 enable_interrupts(I32_bit); 869 if (__predict_true(frame->tf_spsr & F32_bit) == 0) 870 enable_interrupts(F32_bit); 871 } 872 873 syscall(td, frame); 874} 875 876