1 /* 2 * Based on arch/arm/mm/fault.c 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 * Copyright (C) 1995-2004 Russell King 6 * Copyright (C) 2012 ARM Ltd. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program. If not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 #include <linux/module.h> 22 #include <linux/signal.h> 23 #include <linux/mm.h> 24 #include <linux/hardirq.h> 25 #include <linux/init.h> 26 #include <linux/kprobes.h> 27 #include <linux/uaccess.h> 28 #include <linux/page-flags.h> 29 #include <linux/sched.h> 30 #include <linux/highmem.h> 31 #include <linux/perf_event.h> 32 33 #include <asm/cpufeature.h> 34 #include <asm/exception.h> 35 #include <asm/debug-monitors.h> 36 #include <asm/esr.h> 37 #include <asm/sysreg.h> 38 #include <asm/system_misc.h> 39 #include <asm/pgtable.h> 40 #include <asm/tlbflush.h> 41 42 static const char *fault_name(unsigned int esr); 43 44 #ifdef CONFIG_KPROBES 45 static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) 46 { 47 int ret = 0; 48 49 /* kprobe_running() needs smp_processor_id() */ 50 if (!user_mode(regs)) { 51 preempt_disable(); 52 if (kprobe_running() && kprobe_fault_handler(regs, esr)) 53 ret = 1; 54 preempt_enable(); 55 } 56 57 return ret; 58 } 59 #else 60 static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr) 61 { 62 return 0; 63 } 64 #endif 65 66 /* 67 * Dump out the page tables associated with 'addr' in mm 'mm'. 68 */ 69 void show_pte(struct mm_struct *mm, unsigned long addr) 70 { 71 pgd_t *pgd; 72 73 if (!mm) 74 mm = &init_mm; 75 76 pr_alert("pgd = %p\n", mm->pgd); 77 pgd = pgd_offset(mm, addr); 78 pr_alert("[%08lx] *pgd=%016llx", addr, pgd_val(*pgd)); 79 80 do { 81 pud_t *pud; 82 pmd_t *pmd; 83 pte_t *pte; 84 85 if (pgd_none(*pgd) || pgd_bad(*pgd)) 86 break; 87 88 pud = pud_offset(pgd, addr); 89 printk(", *pud=%016llx", pud_val(*pud)); 90 if (pud_none(*pud) || pud_bad(*pud)) 91 break; 92 93 pmd = pmd_offset(pud, addr); 94 printk(", *pmd=%016llx", pmd_val(*pmd)); 95 if (pmd_none(*pmd) || pmd_bad(*pmd)) 96 break; 97 98 pte = pte_offset_map(pmd, addr); 99 printk(", *pte=%016llx", pte_val(*pte)); 100 pte_unmap(pte); 101 } while(0); 102 103 printk("\n"); 104 } 105 106 #ifdef CONFIG_ARM64_HW_AFDBM 107 /* 108 * This function sets the access flags (dirty, accessed), as well as write 109 * permission, and only to a more permissive setting. 110 * 111 * It needs to cope with hardware update of the accessed/dirty state by other 112 * agents in the system and can safely skip the __sync_icache_dcache() call as, 113 * like set_pte_at(), the PTE is never changed from no-exec to exec here. 114 * 115 * Returns whether or not the PTE actually changed. 116 */ 117 int ptep_set_access_flags(struct vm_area_struct *vma, 118 unsigned long address, pte_t *ptep, 119 pte_t entry, int dirty) 120 { 121 pteval_t old_pteval; 122 unsigned int tmp; 123 124 if (pte_same(*ptep, entry)) 125 return 0; 126 127 /* only preserve the access flags and write permission */ 128 pte_val(entry) &= PTE_AF | PTE_WRITE | PTE_DIRTY; 129 130 /* 131 * PTE_RDONLY is cleared by default in the asm below, so set it in 132 * back if necessary (read-only or clean PTE). 133 */ 134 if (!pte_write(entry) || !pte_sw_dirty(entry)) 135 pte_val(entry) |= PTE_RDONLY; 136 137 /* 138 * Setting the flags must be done atomically to avoid racing with the 139 * hardware update of the access/dirty state. 140 */ 141 asm volatile("// ptep_set_access_flags\n" 142 " prfm pstl1strm, %2\n" 143 "1: ldxr %0, %2\n" 144 " and %0, %0, %3 // clear PTE_RDONLY\n" 145 " orr %0, %0, %4 // set flags\n" 146 " stxr %w1, %0, %2\n" 147 " cbnz %w1, 1b\n" 148 : "=&r" (old_pteval), "=&r" (tmp), "+Q" (pte_val(*ptep)) 149 : "L" (~PTE_RDONLY), "r" (pte_val(entry))); 150 151 flush_tlb_fix_spurious_fault(vma, address); 152 return 1; 153 } 154 #endif 155 156 /* 157 * The kernel tried to access some page that wasn't present. 158 */ 159 static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr, 160 unsigned int esr, struct pt_regs *regs) 161 { 162 /* 163 * Are we prepared to handle this kernel fault? 164 */ 165 if (fixup_exception(regs)) 166 return; 167 168 /* 169 * No handler, we'll have to terminate things with extreme prejudice. 170 */ 171 bust_spinlocks(1); 172 pr_alert("Unable to handle kernel %s at virtual address %08lx\n", 173 (addr < PAGE_SIZE) ? "NULL pointer dereference" : 174 "paging request", addr); 175 176 show_pte(mm, addr); 177 die("Oops", regs, esr); 178 bust_spinlocks(0); 179 do_exit(SIGKILL); 180 } 181 182 /* 183 * Something tried to access memory that isn't in our memory map. User mode 184 * accesses just cause a SIGSEGV 185 */ 186 static void __do_user_fault(struct task_struct *tsk, unsigned long addr, 187 unsigned int esr, unsigned int sig, int code, 188 struct pt_regs *regs) 189 { 190 struct siginfo si; 191 192 if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) { 193 pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x\n", 194 tsk->comm, task_pid_nr(tsk), fault_name(esr), sig, 195 addr, esr); 196 show_pte(tsk->mm, addr); 197 show_regs(regs); 198 } 199 200 tsk->thread.fault_address = addr; 201 tsk->thread.fault_code = esr; 202 si.si_signo = sig; 203 si.si_errno = 0; 204 si.si_code = code; 205 si.si_addr = (void __user *)addr; 206 force_sig_info(sig, &si, tsk); 207 } 208 209 static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs) 210 { 211 struct task_struct *tsk = current; 212 struct mm_struct *mm = tsk->active_mm; 213 214 /* 215 * If we are in kernel mode at this point, we have no context to 216 * handle this fault with. 217 */ 218 if (user_mode(regs)) 219 __do_user_fault(tsk, addr, esr, SIGSEGV, SEGV_MAPERR, regs); 220 else 221 __do_kernel_fault(mm, addr, esr, regs); 222 } 223 224 #define VM_FAULT_BADMAP 0x010000 225 #define VM_FAULT_BADACCESS 0x020000 226 227 static int __do_page_fault(struct mm_struct *mm, unsigned long addr, 228 unsigned int mm_flags, unsigned long vm_flags, 229 struct task_struct *tsk) 230 { 231 struct vm_area_struct *vma; 232 int fault; 233 234 vma = find_vma(mm, addr); 235 fault = VM_FAULT_BADMAP; 236 if (unlikely(!vma)) 237 goto out; 238 if (unlikely(vma->vm_start > addr)) 239 goto check_stack; 240 241 /* 242 * Ok, we have a good vm_area for this memory access, so we can handle 243 * it. 244 */ 245 good_area: 246 /* 247 * Check that the permissions on the VMA allow for the fault which 248 * occurred. If we encountered a write or exec fault, we must have 249 * appropriate permissions, otherwise we allow any permission. 250 */ 251 if (!(vma->vm_flags & vm_flags)) { 252 fault = VM_FAULT_BADACCESS; 253 goto out; 254 } 255 256 return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags); 257 258 check_stack: 259 if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) 260 goto good_area; 261 out: 262 return fault; 263 } 264 265 static inline bool is_permission_fault(unsigned int esr) 266 { 267 unsigned int ec = ESR_ELx_EC(esr); 268 unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; 269 270 return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM); 271 } 272 273 static bool is_el0_instruction_abort(unsigned int esr) 274 { 275 return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW; 276 } 277 278 static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 279 struct pt_regs *regs) 280 { 281 struct task_struct *tsk; 282 struct mm_struct *mm; 283 int fault, sig, code; 284 unsigned long vm_flags = VM_READ | VM_WRITE | VM_EXEC; 285 unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; 286 287 if (notify_page_fault(regs, esr)) 288 return 0; 289 290 tsk = current; 291 mm = tsk->mm; 292 293 /* 294 * If we're in an interrupt or have no user context, we must not take 295 * the fault. 296 */ 297 if (faulthandler_disabled() || !mm) 298 goto no_context; 299 300 if (user_mode(regs)) 301 mm_flags |= FAULT_FLAG_USER; 302 303 if (is_el0_instruction_abort(esr)) { 304 vm_flags = VM_EXEC; 305 } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) { 306 vm_flags = VM_WRITE; 307 mm_flags |= FAULT_FLAG_WRITE; 308 } 309 310 if (is_permission_fault(esr) && (addr < USER_DS)) { 311 /* regs->orig_addr_limit may be 0 if we entered from EL0 */ 312 if (regs->orig_addr_limit == KERNEL_DS) 313 die("Accessing user space memory with fs=KERNEL_DS", regs, esr); 314 315 if (!search_exception_tables(regs->pc)) 316 die("Accessing user space memory outside uaccess.h routines", regs, esr); 317 } 318 319 /* 320 * As per x86, we may deadlock here. However, since the kernel only 321 * validly references user space from well defined areas of the code, 322 * we can bug out early if this is from code which shouldn't. 323 */ 324 if (!down_read_trylock(&mm->mmap_sem)) { 325 if (!user_mode(regs) && !search_exception_tables(regs->pc)) 326 goto no_context; 327 retry: 328 down_read(&mm->mmap_sem); 329 } else { 330 /* 331 * The above down_read_trylock() might have succeeded in which 332 * case, we'll have missed the might_sleep() from down_read(). 333 */ 334 might_sleep(); 335 #ifdef CONFIG_DEBUG_VM 336 if (!user_mode(regs) && !search_exception_tables(regs->pc)) 337 goto no_context; 338 #endif 339 } 340 341 fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk); 342 343 /* 344 * If we need to retry but a fatal signal is pending, handle the 345 * signal first. We do not need to release the mmap_sem because it 346 * would already be released in __lock_page_or_retry in mm/filemap.c. 347 */ 348 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) 349 return 0; 350 351 /* 352 * Major/minor page fault accounting is only done on the initial 353 * attempt. If we go through a retry, it is extremely likely that the 354 * page will be found in page cache at that point. 355 */ 356 357 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); 358 if (mm_flags & FAULT_FLAG_ALLOW_RETRY) { 359 if (fault & VM_FAULT_MAJOR) { 360 tsk->maj_flt++; 361 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, 362 addr); 363 } else { 364 tsk->min_flt++; 365 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, 366 addr); 367 } 368 if (fault & VM_FAULT_RETRY) { 369 /* 370 * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of 371 * starvation. 372 */ 373 mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; 374 mm_flags |= FAULT_FLAG_TRIED; 375 goto retry; 376 } 377 } 378 379 up_read(&mm->mmap_sem); 380 381 /* 382 * Handle the "normal" case first - VM_FAULT_MAJOR 383 */ 384 if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | 385 VM_FAULT_BADACCESS)))) 386 return 0; 387 388 /* 389 * If we are in kernel mode at this point, we have no context to 390 * handle this fault with. 391 */ 392 if (!user_mode(regs)) 393 goto no_context; 394 395 if (fault & VM_FAULT_OOM) { 396 /* 397 * We ran out of memory, call the OOM killer, and return to 398 * userspace (which will retry the fault, or kill us if we got 399 * oom-killed). 400 */ 401 pagefault_out_of_memory(); 402 return 0; 403 } 404 405 if (fault & VM_FAULT_SIGBUS) { 406 /* 407 * We had some memory, but were unable to successfully fix up 408 * this page fault. 409 */ 410 sig = SIGBUS; 411 code = BUS_ADRERR; 412 } else { 413 /* 414 * Something tried to access memory that isn't in our memory 415 * map. 416 */ 417 sig = SIGSEGV; 418 code = fault == VM_FAULT_BADACCESS ? 419 SEGV_ACCERR : SEGV_MAPERR; 420 } 421 422 __do_user_fault(tsk, addr, esr, sig, code, regs); 423 return 0; 424 425 no_context: 426 __do_kernel_fault(mm, addr, esr, regs); 427 return 0; 428 } 429 430 /* 431 * First Level Translation Fault Handler 432 * 433 * We enter here because the first level page table doesn't contain a valid 434 * entry for the address. 435 * 436 * If the address is in kernel space (>= TASK_SIZE), then we are probably 437 * faulting in the vmalloc() area. 438 * 439 * If the init_task's first level page tables contains the relevant entry, we 440 * copy the it to this task. If not, we send the process a signal, fixup the 441 * exception, or oops the kernel. 442 * 443 * NOTE! We MUST NOT take any locks for this case. We may be in an interrupt 444 * or a critical region, and should only copy the information from the master 445 * page table, nothing more. 446 */ 447 static int __kprobes do_translation_fault(unsigned long addr, 448 unsigned int esr, 449 struct pt_regs *regs) 450 { 451 if (addr < TASK_SIZE) 452 return do_page_fault(addr, esr, regs); 453 454 do_bad_area(addr, esr, regs); 455 return 0; 456 } 457 458 static int do_alignment_fault(unsigned long addr, unsigned int esr, 459 struct pt_regs *regs) 460 { 461 do_bad_area(addr, esr, regs); 462 return 0; 463 } 464 465 /* 466 * This abort handler always returns "fault". 467 */ 468 static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) 469 { 470 return 1; 471 } 472 473 static const struct fault_info { 474 int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs); 475 int sig; 476 int code; 477 const char *name; 478 } fault_info[] = { 479 { do_bad, SIGBUS, 0, "ttbr address size fault" }, 480 { do_bad, SIGBUS, 0, "level 1 address size fault" }, 481 { do_bad, SIGBUS, 0, "level 2 address size fault" }, 482 { do_bad, SIGBUS, 0, "level 3 address size fault" }, 483 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" }, 484 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" }, 485 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" }, 486 { do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, 487 { do_bad, SIGBUS, 0, "unknown 8" }, 488 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, 489 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" }, 490 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" }, 491 { do_bad, SIGBUS, 0, "unknown 12" }, 492 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, 493 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, 494 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, 495 { do_bad, SIGBUS, 0, "synchronous external abort" }, 496 { do_bad, SIGBUS, 0, "unknown 17" }, 497 { do_bad, SIGBUS, 0, "unknown 18" }, 498 { do_bad, SIGBUS, 0, "unknown 19" }, 499 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, 500 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, 501 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, 502 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, 503 { do_bad, SIGBUS, 0, "synchronous parity error" }, 504 { do_bad, SIGBUS, 0, "unknown 25" }, 505 { do_bad, SIGBUS, 0, "unknown 26" }, 506 { do_bad, SIGBUS, 0, "unknown 27" }, 507 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, 508 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, 509 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, 510 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, 511 { do_bad, SIGBUS, 0, "unknown 32" }, 512 { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, 513 { do_bad, SIGBUS, 0, "unknown 34" }, 514 { do_bad, SIGBUS, 0, "unknown 35" }, 515 { do_bad, SIGBUS, 0, "unknown 36" }, 516 { do_bad, SIGBUS, 0, "unknown 37" }, 517 { do_bad, SIGBUS, 0, "unknown 38" }, 518 { do_bad, SIGBUS, 0, "unknown 39" }, 519 { do_bad, SIGBUS, 0, "unknown 40" }, 520 { do_bad, SIGBUS, 0, "unknown 41" }, 521 { do_bad, SIGBUS, 0, "unknown 42" }, 522 { do_bad, SIGBUS, 0, "unknown 43" }, 523 { do_bad, SIGBUS, 0, "unknown 44" }, 524 { do_bad, SIGBUS, 0, "unknown 45" }, 525 { do_bad, SIGBUS, 0, "unknown 46" }, 526 { do_bad, SIGBUS, 0, "unknown 47" }, 527 { do_bad, SIGBUS, 0, "TLB conflict abort" }, 528 { do_bad, SIGBUS, 0, "unknown 49" }, 529 { do_bad, SIGBUS, 0, "unknown 50" }, 530 { do_bad, SIGBUS, 0, "unknown 51" }, 531 { do_bad, SIGBUS, 0, "implementation fault (lockdown abort)" }, 532 { do_bad, SIGBUS, 0, "implementation fault (unsupported exclusive)" }, 533 { do_bad, SIGBUS, 0, "unknown 54" }, 534 { do_bad, SIGBUS, 0, "unknown 55" }, 535 { do_bad, SIGBUS, 0, "unknown 56" }, 536 { do_bad, SIGBUS, 0, "unknown 57" }, 537 { do_bad, SIGBUS, 0, "unknown 58" }, 538 { do_bad, SIGBUS, 0, "unknown 59" }, 539 { do_bad, SIGBUS, 0, "unknown 60" }, 540 { do_bad, SIGBUS, 0, "section domain fault" }, 541 { do_bad, SIGBUS, 0, "page domain fault" }, 542 { do_bad, SIGBUS, 0, "unknown 63" }, 543 }; 544 545 static const char *fault_name(unsigned int esr) 546 { 547 const struct fault_info *inf = fault_info + (esr & 63); 548 return inf->name; 549 } 550 551 /* 552 * Dispatch a data abort to the relevant handler. 553 */ 554 asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, 555 struct pt_regs *regs) 556 { 557 const struct fault_info *inf = fault_info + (esr & 63); 558 struct siginfo info; 559 560 if (!inf->fn(addr, esr, regs)) 561 return; 562 563 pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n", 564 inf->name, esr, addr); 565 566 info.si_signo = inf->sig; 567 info.si_errno = 0; 568 info.si_code = inf->code; 569 info.si_addr = (void __user *)addr; 570 arm64_notify_die("", regs, &info, esr); 571 } 572 573 /* 574 * Handle stack alignment exceptions. 575 */ 576 asmlinkage void __exception do_sp_pc_abort(unsigned long addr, 577 unsigned int esr, 578 struct pt_regs *regs) 579 { 580 struct siginfo info; 581 struct task_struct *tsk = current; 582 583 if (show_unhandled_signals && unhandled_signal(tsk, SIGBUS)) 584 pr_info_ratelimited("%s[%d]: %s exception: pc=%p sp=%p\n", 585 tsk->comm, task_pid_nr(tsk), 586 esr_get_class_string(esr), (void *)regs->pc, 587 (void *)regs->sp); 588 589 info.si_signo = SIGBUS; 590 info.si_errno = 0; 591 info.si_code = BUS_ADRALN; 592 info.si_addr = (void __user *)addr; 593 arm64_notify_die("Oops - SP/PC alignment exception", regs, &info, esr); 594 } 595 596 int __init early_brk64(unsigned long addr, unsigned int esr, 597 struct pt_regs *regs); 598 599 /* 600 * __refdata because early_brk64 is __init, but the reference to it is 601 * clobbered at arch_initcall time. 602 * See traps.c and debug-monitors.c:debug_traps_init(). 603 */ 604 static struct fault_info __refdata debug_fault_info[] = { 605 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" }, 606 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" }, 607 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" }, 608 { do_bad, SIGBUS, 0, "unknown 3" }, 609 { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" }, 610 { do_bad, SIGTRAP, 0, "aarch32 vector catch" }, 611 { early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" }, 612 { do_bad, SIGBUS, 0, "unknown 7" }, 613 }; 614 615 void __init hook_debug_fault_code(int nr, 616 int (*fn)(unsigned long, unsigned int, struct pt_regs *), 617 int sig, int code, const char *name) 618 { 619 BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info)); 620 621 debug_fault_info[nr].fn = fn; 622 debug_fault_info[nr].sig = sig; 623 debug_fault_info[nr].code = code; 624 debug_fault_info[nr].name = name; 625 } 626 627 asmlinkage int __exception do_debug_exception(unsigned long addr, 628 unsigned int esr, 629 struct pt_regs *regs) 630 { 631 const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr); 632 struct siginfo info; 633 int rv; 634 635 /* 636 * Tell lockdep we disabled irqs in entry.S. Do nothing if they were 637 * already disabled to preserve the last enabled/disabled addresses. 638 */ 639 if (interrupts_enabled(regs)) 640 trace_hardirqs_off(); 641 642 if (!inf->fn(addr, esr, regs)) { 643 rv = 1; 644 } else { 645 pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n", 646 inf->name, esr, addr); 647 648 info.si_signo = inf->sig; 649 info.si_errno = 0; 650 info.si_code = inf->code; 651 info.si_addr = (void __user *)addr; 652 arm64_notify_die("", regs, &info, 0); 653 rv = 0; 654 } 655 656 if (interrupts_enabled(regs)) 657 trace_hardirqs_on(); 658 659 return rv; 660 } 661 NOKPROBE_SYMBOL(do_debug_exception); 662 663 #ifdef CONFIG_ARM64_PAN 664 void cpu_enable_pan(void *__unused) 665 { 666 config_sctlr_el1(SCTLR_EL1_SPAN, 0); 667 } 668 #endif /* CONFIG_ARM64_PAN */ 669 670 #ifdef CONFIG_ARM64_UAO 671 /* 672 * Kernel threads have fs=KERNEL_DS by default, and don't need to call 673 * set_fs(), devtmpfs in particular relies on this behaviour. 674 * We need to enable the feature at runtime (instead of adding it to 675 * PSR_MODE_EL1h) as the feature may not be implemented by the cpu. 676 */ 677 void cpu_enable_uao(void *__unused) 678 { 679 asm(SET_PSTATE_UAO(1)); 680 } 681 #endif /* CONFIG_ARM64_UAO */ 682