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/extable.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 static bool is_el1_instruction_abort(unsigned int esr) 157 { 158 return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_CUR; 159 } 160 161 /* 162 * The kernel tried to access some page that wasn't present. 163 */ 164 static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr, 165 unsigned int esr, struct pt_regs *regs) 166 { 167 /* 168 * Are we prepared to handle this kernel fault? 169 * We are almost certainly not prepared to handle instruction faults. 170 */ 171 if (!is_el1_instruction_abort(esr) && fixup_exception(regs)) 172 return; 173 174 /* 175 * No handler, we'll have to terminate things with extreme prejudice. 176 */ 177 bust_spinlocks(1); 178 pr_alert("Unable to handle kernel %s at virtual address %08lx\n", 179 (addr < PAGE_SIZE) ? "NULL pointer dereference" : 180 "paging request", addr); 181 182 show_pte(mm, addr); 183 die("Oops", regs, esr); 184 bust_spinlocks(0); 185 do_exit(SIGKILL); 186 } 187 188 /* 189 * Something tried to access memory that isn't in our memory map. User mode 190 * accesses just cause a SIGSEGV 191 */ 192 static void __do_user_fault(struct task_struct *tsk, unsigned long addr, 193 unsigned int esr, unsigned int sig, int code, 194 struct pt_regs *regs) 195 { 196 struct siginfo si; 197 198 if (unhandled_signal(tsk, sig) && show_unhandled_signals_ratelimited()) { 199 pr_info("%s[%d]: unhandled %s (%d) at 0x%08lx, esr 0x%03x\n", 200 tsk->comm, task_pid_nr(tsk), fault_name(esr), sig, 201 addr, esr); 202 show_pte(tsk->mm, addr); 203 show_regs(regs); 204 } 205 206 tsk->thread.fault_address = addr; 207 tsk->thread.fault_code = esr; 208 si.si_signo = sig; 209 si.si_errno = 0; 210 si.si_code = code; 211 si.si_addr = (void __user *)addr; 212 force_sig_info(sig, &si, tsk); 213 } 214 215 static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *regs) 216 { 217 struct task_struct *tsk = current; 218 struct mm_struct *mm = tsk->active_mm; 219 220 /* 221 * If we are in kernel mode at this point, we have no context to 222 * handle this fault with. 223 */ 224 if (user_mode(regs)) 225 __do_user_fault(tsk, addr, esr, SIGSEGV, SEGV_MAPERR, regs); 226 else 227 __do_kernel_fault(mm, addr, esr, regs); 228 } 229 230 #define VM_FAULT_BADMAP 0x010000 231 #define VM_FAULT_BADACCESS 0x020000 232 233 static int __do_page_fault(struct mm_struct *mm, unsigned long addr, 234 unsigned int mm_flags, unsigned long vm_flags, 235 struct task_struct *tsk) 236 { 237 struct vm_area_struct *vma; 238 int fault; 239 240 vma = find_vma(mm, addr); 241 fault = VM_FAULT_BADMAP; 242 if (unlikely(!vma)) 243 goto out; 244 if (unlikely(vma->vm_start > addr)) 245 goto check_stack; 246 247 /* 248 * Ok, we have a good vm_area for this memory access, so we can handle 249 * it. 250 */ 251 good_area: 252 /* 253 * Check that the permissions on the VMA allow for the fault which 254 * occurred. 255 */ 256 if (!(vma->vm_flags & vm_flags)) { 257 fault = VM_FAULT_BADACCESS; 258 goto out; 259 } 260 261 return handle_mm_fault(vma, addr & PAGE_MASK, mm_flags); 262 263 check_stack: 264 if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr)) 265 goto good_area; 266 out: 267 return fault; 268 } 269 270 static inline bool is_permission_fault(unsigned int esr) 271 { 272 unsigned int ec = ESR_ELx_EC(esr); 273 unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; 274 275 return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM) || 276 (ec == ESR_ELx_EC_IABT_CUR && fsc_type == ESR_ELx_FSC_PERM); 277 } 278 279 static bool is_el0_instruction_abort(unsigned int esr) 280 { 281 return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW; 282 } 283 284 static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 285 struct pt_regs *regs) 286 { 287 struct task_struct *tsk; 288 struct mm_struct *mm; 289 int fault, sig, code; 290 unsigned long vm_flags = VM_READ | VM_WRITE; 291 unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; 292 293 if (notify_page_fault(regs, esr)) 294 return 0; 295 296 tsk = current; 297 mm = tsk->mm; 298 299 /* 300 * If we're in an interrupt or have no user context, we must not take 301 * the fault. 302 */ 303 if (faulthandler_disabled() || !mm) 304 goto no_context; 305 306 if (user_mode(regs)) 307 mm_flags |= FAULT_FLAG_USER; 308 309 if (is_el0_instruction_abort(esr)) { 310 vm_flags = VM_EXEC; 311 } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) { 312 vm_flags = VM_WRITE; 313 mm_flags |= FAULT_FLAG_WRITE; 314 } 315 316 if (is_permission_fault(esr) && (addr < USER_DS)) { 317 /* regs->orig_addr_limit may be 0 if we entered from EL0 */ 318 if (regs->orig_addr_limit == KERNEL_DS) 319 die("Accessing user space memory with fs=KERNEL_DS", regs, esr); 320 321 if (is_el1_instruction_abort(esr)) 322 die("Attempting to execute userspace memory", regs, esr); 323 324 if (!search_exception_tables(regs->pc)) 325 die("Accessing user space memory outside uaccess.h routines", regs, esr); 326 } 327 328 /* 329 * As per x86, we may deadlock here. However, since the kernel only 330 * validly references user space from well defined areas of the code, 331 * we can bug out early if this is from code which shouldn't. 332 */ 333 if (!down_read_trylock(&mm->mmap_sem)) { 334 if (!user_mode(regs) && !search_exception_tables(regs->pc)) 335 goto no_context; 336 retry: 337 down_read(&mm->mmap_sem); 338 } else { 339 /* 340 * The above down_read_trylock() might have succeeded in which 341 * case, we'll have missed the might_sleep() from down_read(). 342 */ 343 might_sleep(); 344 #ifdef CONFIG_DEBUG_VM 345 if (!user_mode(regs) && !search_exception_tables(regs->pc)) 346 goto no_context; 347 #endif 348 } 349 350 fault = __do_page_fault(mm, addr, mm_flags, vm_flags, tsk); 351 352 /* 353 * If we need to retry but a fatal signal is pending, handle the 354 * signal first. We do not need to release the mmap_sem because it 355 * would already be released in __lock_page_or_retry in mm/filemap.c. 356 */ 357 if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) 358 return 0; 359 360 /* 361 * Major/minor page fault accounting is only done on the initial 362 * attempt. If we go through a retry, it is extremely likely that the 363 * page will be found in page cache at that point. 364 */ 365 366 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr); 367 if (mm_flags & FAULT_FLAG_ALLOW_RETRY) { 368 if (fault & VM_FAULT_MAJOR) { 369 tsk->maj_flt++; 370 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, regs, 371 addr); 372 } else { 373 tsk->min_flt++; 374 perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, regs, 375 addr); 376 } 377 if (fault & VM_FAULT_RETRY) { 378 /* 379 * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of 380 * starvation. 381 */ 382 mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; 383 mm_flags |= FAULT_FLAG_TRIED; 384 goto retry; 385 } 386 } 387 388 up_read(&mm->mmap_sem); 389 390 /* 391 * Handle the "normal" case first - VM_FAULT_MAJOR 392 */ 393 if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | 394 VM_FAULT_BADACCESS)))) 395 return 0; 396 397 /* 398 * If we are in kernel mode at this point, we have no context to 399 * handle this fault with. 400 */ 401 if (!user_mode(regs)) 402 goto no_context; 403 404 if (fault & VM_FAULT_OOM) { 405 /* 406 * We ran out of memory, call the OOM killer, and return to 407 * userspace (which will retry the fault, or kill us if we got 408 * oom-killed). 409 */ 410 pagefault_out_of_memory(); 411 return 0; 412 } 413 414 if (fault & VM_FAULT_SIGBUS) { 415 /* 416 * We had some memory, but were unable to successfully fix up 417 * this page fault. 418 */ 419 sig = SIGBUS; 420 code = BUS_ADRERR; 421 } else { 422 /* 423 * Something tried to access memory that isn't in our memory 424 * map. 425 */ 426 sig = SIGSEGV; 427 code = fault == VM_FAULT_BADACCESS ? 428 SEGV_ACCERR : SEGV_MAPERR; 429 } 430 431 __do_user_fault(tsk, addr, esr, sig, code, regs); 432 return 0; 433 434 no_context: 435 __do_kernel_fault(mm, addr, esr, regs); 436 return 0; 437 } 438 439 /* 440 * First Level Translation Fault Handler 441 * 442 * We enter here because the first level page table doesn't contain a valid 443 * entry for the address. 444 * 445 * If the address is in kernel space (>= TASK_SIZE), then we are probably 446 * faulting in the vmalloc() area. 447 * 448 * If the init_task's first level page tables contains the relevant entry, we 449 * copy the it to this task. If not, we send the process a signal, fixup the 450 * exception, or oops the kernel. 451 * 452 * NOTE! We MUST NOT take any locks for this case. We may be in an interrupt 453 * or a critical region, and should only copy the information from the master 454 * page table, nothing more. 455 */ 456 static int __kprobes do_translation_fault(unsigned long addr, 457 unsigned int esr, 458 struct pt_regs *regs) 459 { 460 if (addr < TASK_SIZE) 461 return do_page_fault(addr, esr, regs); 462 463 do_bad_area(addr, esr, regs); 464 return 0; 465 } 466 467 static int do_alignment_fault(unsigned long addr, unsigned int esr, 468 struct pt_regs *regs) 469 { 470 do_bad_area(addr, esr, regs); 471 return 0; 472 } 473 474 /* 475 * This abort handler always returns "fault". 476 */ 477 static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) 478 { 479 return 1; 480 } 481 482 static const struct fault_info { 483 int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs); 484 int sig; 485 int code; 486 const char *name; 487 } fault_info[] = { 488 { do_bad, SIGBUS, 0, "ttbr address size fault" }, 489 { do_bad, SIGBUS, 0, "level 1 address size fault" }, 490 { do_bad, SIGBUS, 0, "level 2 address size fault" }, 491 { do_bad, SIGBUS, 0, "level 3 address size fault" }, 492 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" }, 493 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" }, 494 { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" }, 495 { do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, 496 { do_bad, SIGBUS, 0, "unknown 8" }, 497 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, 498 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" }, 499 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 access flag fault" }, 500 { do_bad, SIGBUS, 0, "unknown 12" }, 501 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, 502 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, 503 { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, 504 { do_bad, SIGBUS, 0, "synchronous external abort" }, 505 { do_bad, SIGBUS, 0, "unknown 17" }, 506 { do_bad, SIGBUS, 0, "unknown 18" }, 507 { do_bad, SIGBUS, 0, "unknown 19" }, 508 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, 509 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, 510 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, 511 { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, 512 { do_bad, SIGBUS, 0, "synchronous parity error" }, 513 { do_bad, SIGBUS, 0, "unknown 25" }, 514 { do_bad, SIGBUS, 0, "unknown 26" }, 515 { do_bad, SIGBUS, 0, "unknown 27" }, 516 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, 517 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, 518 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, 519 { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, 520 { do_bad, SIGBUS, 0, "unknown 32" }, 521 { do_alignment_fault, SIGBUS, BUS_ADRALN, "alignment fault" }, 522 { do_bad, SIGBUS, 0, "unknown 34" }, 523 { do_bad, SIGBUS, 0, "unknown 35" }, 524 { do_bad, SIGBUS, 0, "unknown 36" }, 525 { do_bad, SIGBUS, 0, "unknown 37" }, 526 { do_bad, SIGBUS, 0, "unknown 38" }, 527 { do_bad, SIGBUS, 0, "unknown 39" }, 528 { do_bad, SIGBUS, 0, "unknown 40" }, 529 { do_bad, SIGBUS, 0, "unknown 41" }, 530 { do_bad, SIGBUS, 0, "unknown 42" }, 531 { do_bad, SIGBUS, 0, "unknown 43" }, 532 { do_bad, SIGBUS, 0, "unknown 44" }, 533 { do_bad, SIGBUS, 0, "unknown 45" }, 534 { do_bad, SIGBUS, 0, "unknown 46" }, 535 { do_bad, SIGBUS, 0, "unknown 47" }, 536 { do_bad, SIGBUS, 0, "TLB conflict abort" }, 537 { do_bad, SIGBUS, 0, "unknown 49" }, 538 { do_bad, SIGBUS, 0, "unknown 50" }, 539 { do_bad, SIGBUS, 0, "unknown 51" }, 540 { do_bad, SIGBUS, 0, "implementation fault (lockdown abort)" }, 541 { do_bad, SIGBUS, 0, "implementation fault (unsupported exclusive)" }, 542 { do_bad, SIGBUS, 0, "unknown 54" }, 543 { do_bad, SIGBUS, 0, "unknown 55" }, 544 { do_bad, SIGBUS, 0, "unknown 56" }, 545 { do_bad, SIGBUS, 0, "unknown 57" }, 546 { do_bad, SIGBUS, 0, "unknown 58" }, 547 { do_bad, SIGBUS, 0, "unknown 59" }, 548 { do_bad, SIGBUS, 0, "unknown 60" }, 549 { do_bad, SIGBUS, 0, "section domain fault" }, 550 { do_bad, SIGBUS, 0, "page domain fault" }, 551 { do_bad, SIGBUS, 0, "unknown 63" }, 552 }; 553 554 static const char *fault_name(unsigned int esr) 555 { 556 const struct fault_info *inf = fault_info + (esr & 63); 557 return inf->name; 558 } 559 560 /* 561 * Dispatch a data abort to the relevant handler. 562 */ 563 asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, 564 struct pt_regs *regs) 565 { 566 const struct fault_info *inf = fault_info + (esr & 63); 567 struct siginfo info; 568 569 if (!inf->fn(addr, esr, regs)) 570 return; 571 572 pr_alert("Unhandled fault: %s (0x%08x) at 0x%016lx\n", 573 inf->name, esr, addr); 574 575 info.si_signo = inf->sig; 576 info.si_errno = 0; 577 info.si_code = inf->code; 578 info.si_addr = (void __user *)addr; 579 arm64_notify_die("", regs, &info, esr); 580 } 581 582 /* 583 * Handle stack alignment exceptions. 584 */ 585 asmlinkage void __exception do_sp_pc_abort(unsigned long addr, 586 unsigned int esr, 587 struct pt_regs *regs) 588 { 589 struct siginfo info; 590 struct task_struct *tsk = current; 591 592 if (show_unhandled_signals && unhandled_signal(tsk, SIGBUS)) 593 pr_info_ratelimited("%s[%d]: %s exception: pc=%p sp=%p\n", 594 tsk->comm, task_pid_nr(tsk), 595 esr_get_class_string(esr), (void *)regs->pc, 596 (void *)regs->sp); 597 598 info.si_signo = SIGBUS; 599 info.si_errno = 0; 600 info.si_code = BUS_ADRALN; 601 info.si_addr = (void __user *)addr; 602 arm64_notify_die("Oops - SP/PC alignment exception", regs, &info, esr); 603 } 604 605 int __init early_brk64(unsigned long addr, unsigned int esr, 606 struct pt_regs *regs); 607 608 /* 609 * __refdata because early_brk64 is __init, but the reference to it is 610 * clobbered at arch_initcall time. 611 * See traps.c and debug-monitors.c:debug_traps_init(). 612 */ 613 static struct fault_info __refdata debug_fault_info[] = { 614 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware breakpoint" }, 615 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware single-step" }, 616 { do_bad, SIGTRAP, TRAP_HWBKPT, "hardware watchpoint" }, 617 { do_bad, SIGBUS, 0, "unknown 3" }, 618 { do_bad, SIGTRAP, TRAP_BRKPT, "aarch32 BKPT" }, 619 { do_bad, SIGTRAP, 0, "aarch32 vector catch" }, 620 { early_brk64, SIGTRAP, TRAP_BRKPT, "aarch64 BRK" }, 621 { do_bad, SIGBUS, 0, "unknown 7" }, 622 }; 623 624 void __init hook_debug_fault_code(int nr, 625 int (*fn)(unsigned long, unsigned int, struct pt_regs *), 626 int sig, int code, const char *name) 627 { 628 BUG_ON(nr < 0 || nr >= ARRAY_SIZE(debug_fault_info)); 629 630 debug_fault_info[nr].fn = fn; 631 debug_fault_info[nr].sig = sig; 632 debug_fault_info[nr].code = code; 633 debug_fault_info[nr].name = name; 634 } 635 636 asmlinkage int __exception do_debug_exception(unsigned long addr, 637 unsigned int esr, 638 struct pt_regs *regs) 639 { 640 const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr); 641 struct siginfo info; 642 int rv; 643 644 /* 645 * Tell lockdep we disabled irqs in entry.S. Do nothing if they were 646 * already disabled to preserve the last enabled/disabled addresses. 647 */ 648 if (interrupts_enabled(regs)) 649 trace_hardirqs_off(); 650 651 if (!inf->fn(addr, esr, regs)) { 652 rv = 1; 653 } else { 654 pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n", 655 inf->name, esr, addr); 656 657 info.si_signo = inf->sig; 658 info.si_errno = 0; 659 info.si_code = inf->code; 660 info.si_addr = (void __user *)addr; 661 arm64_notify_die("", regs, &info, 0); 662 rv = 0; 663 } 664 665 if (interrupts_enabled(regs)) 666 trace_hardirqs_on(); 667 668 return rv; 669 } 670 NOKPROBE_SYMBOL(do_debug_exception); 671 672 #ifdef CONFIG_ARM64_PAN 673 void cpu_enable_pan(void *__unused) 674 { 675 config_sctlr_el1(SCTLR_EL1_SPAN, 0); 676 } 677 #endif /* CONFIG_ARM64_PAN */ 678 679 #ifdef CONFIG_ARM64_UAO 680 /* 681 * Kernel threads have fs=KERNEL_DS by default, and don't need to call 682 * set_fs(), devtmpfs in particular relies on this behaviour. 683 * We need to enable the feature at runtime (instead of adding it to 684 * PSR_MODE_EL1h) as the feature may not be implemented by the cpu. 685 */ 686 void cpu_enable_uao(void *__unused) 687 { 688 asm(SET_PSTATE_UAO(1)); 689 } 690 #endif /* CONFIG_ARM64_UAO */ 691