mm/kasan/kasan.c

   1 /*
   2  * This file contains shadow memory manipulation code.
   3  *
   4  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   5  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
   6  *
   7  * Some code borrowed from https://github.com/xairy/kasan-prototype by
   8  *        Andrey Konovalov <adech.fo@gmail.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  */
  15
  16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17 #define DISABLE_BRANCH_PROFILING
  18
  19 #include <linux/export.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/init.h>
  22 #include <linux/kasan.h>
  23 #include <linux/kernel.h>
  24 #include <linux/kmemleak.h>
  25 #include <linux/linkage.h>
  26 #include <linux/memblock.h>
  27 #include <linux/memory.h>
  28 #include <linux/mm.h>
  29 #include <linux/module.h>
  30 #include <linux/printk.h>
  31 #include <linux/sched.h>
  32 #include <linux/slab.h>
  33 #include <linux/stacktrace.h>
  34 #include <linux/string.h>
  35 #include <linux/types.h>
  36 #include <linux/vmalloc.h>
  37
  38 #include "kasan.h"
  39 #include "../slab.h"
  40
  41 /*
  42  * Poisons the shadow memory for 'size' bytes starting from 'addr'.
  43  * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
  44  */
  45 static void kasan_poison_shadow(const void *address, size_t size, u8 value)
  46 {
  47         void *shadow_start, *shadow_end;
  48
  49         shadow_start = kasan_mem_to_shadow(address);
  50         shadow_end = kasan_mem_to_shadow(address + size);
  51
  52         memset(shadow_start, value, shadow_end - shadow_start);
  53 }
  54
  55 void kasan_unpoison_shadow(const void *address, size_t size)
  56 {
  57         kasan_poison_shadow(address, size, 0);
  58
  59         if (size & KASAN_SHADOW_MASK) {
  60                 u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
  61                 *shadow = size & KASAN_SHADOW_MASK;
  62         }
  63 }
  64
  65 static void __kasan_unpoison_stack(struct task_struct *task, void *sp)
  66 {
  67         void *base = task_stack_page(task);
  68         size_t size = sp - base;
  69
  70         kasan_unpoison_shadow(base, size);
  71 }
  72
  73 /* Unpoison the entire stack for a task. */
  74 void kasan_unpoison_task_stack(struct task_struct *task)
  75 {
  76         __kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE);
  77 }
  78
  79 /* Unpoison the stack for the current task beyond a watermark sp value. */
  80 asmlinkage void kasan_unpoison_remaining_stack(void *sp)
  81 {
  82         __kasan_unpoison_stack(current, sp);
  83 }
  84
  85 /*
  86  * All functions below always inlined so compiler could
  87  * perform better optimizations in each of __asan_loadX/__assn_storeX
  88  * depending on memory access size X.
  89  */
  90
  91 static __always_inline bool memory_is_poisoned_1(unsigned long addr)
  92 {
  93         s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
  94
  95         if (unlikely(shadow_value)) {
  96                 s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
  97                 return unlikely(last_accessible_byte >= shadow_value);
  98         }
  99
 100         return false;
 101 }
 102
 103 static __always_inline bool memory_is_poisoned_2(unsigned long addr)
 104 {
 105         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 106
 107         if (unlikely(*shadow_addr)) {
 108                 if (memory_is_poisoned_1(addr + 1))
 109                         return true;
 110
 111                 /*
 112                  * If single shadow byte covers 2-byte access, we don't
 113                  * need to do anything more. Otherwise, test the first
 114                  * shadow byte.
 115                  */
 116                 if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
 117                         return false;
 118
 119                 return unlikely(*(u8 *)shadow_addr);
 120         }
 121
 122         return false;
 123 }
 124
 125 static __always_inline bool memory_is_poisoned_4(unsigned long addr)
 126 {
 127         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 128
 129         if (unlikely(*shadow_addr)) {
 130                 if (memory_is_poisoned_1(addr + 3))
 131                         return true;
 132
 133                 /*
 134                  * If single shadow byte covers 4-byte access, we don't
 135                  * need to do anything more. Otherwise, test the first
 136                  * shadow byte.
 137                  */
 138                 if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
 139                         return false;
 140
 141                 return unlikely(*(u8 *)shadow_addr);
 142         }
 143
 144         return false;
 145 }
 146
 147 static __always_inline bool memory_is_poisoned_8(unsigned long addr)
 148 {
 149         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 150
 151         if (unlikely(*shadow_addr)) {
 152                 if (memory_is_poisoned_1(addr + 7))
 153                         return true;
 154
 155                 /*
 156                  * If single shadow byte covers 8-byte access, we don't
 157                  * need to do anything more. Otherwise, test the first
 158                  * shadow byte.
 159                  */
 160                 if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 161                         return false;
 162
 163                 return unlikely(*(u8 *)shadow_addr);
 164         }
 165
 166         return false;
 167 }
 168
 169 static __always_inline bool memory_is_poisoned_16(unsigned long addr)
 170 {
 171         u32 *shadow_addr = (u32 *)kasan_mem_to_shadow((void *)addr);
 172
 173         if (unlikely(*shadow_addr)) {
 174                 u16 shadow_first_bytes = *(u16 *)shadow_addr;
 175
 176                 if (unlikely(shadow_first_bytes))
 177                         return true;
 178
 179                 /*
 180                  * If two shadow bytes covers 16-byte access, we don't
 181                  * need to do anything more. Otherwise, test the last
 182                  * shadow byte.
 183                  */
 184                 if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 185                         return false;
 186
 187                 return memory_is_poisoned_1(addr + 15);
 188         }
 189
 190         return false;
 191 }
 192
 193 static __always_inline unsigned long bytes_is_zero(const u8 *start,
 194                                         size_t size)
 195 {
 196         while (size) {
 197                 if (unlikely(*start))
 198                         return (unsigned long)start;
 199                 start++;
 200                 size--;
 201         }
 202
 203         return 0;
 204 }
 205
 206 static __always_inline unsigned long memory_is_zero(const void *start,
 207                                                 const void *end)
 208 {
 209         unsigned int words;
 210         unsigned long ret;
 211         unsigned int prefix = (unsigned long)start % 8;
 212
 213         if (end - start <= 16)
 214                 return bytes_is_zero(start, end - start);
 215
 216         if (prefix) {
 217                 prefix = 8 - prefix;
 218                 ret = bytes_is_zero(start, prefix);
 219                 if (unlikely(ret))
 220                         return ret;
 221                 start += prefix;
 222         }
 223
 224         words = (end - start) / 8;
 225         while (words) {
 226                 if (unlikely(*(u64 *)start))
 227                         return bytes_is_zero(start, 8);
 228                 start += 8;
 229                 words--;
 230         }
 231
 232         return bytes_is_zero(start, (end - start) % 8);
 233 }
 234
 235 static __always_inline bool memory_is_poisoned_n(unsigned long addr,
 236                                                 size_t size)
 237 {
 238         unsigned long ret;
 239
 240         ret = memory_is_zero(kasan_mem_to_shadow((void *)addr),
 241                         kasan_mem_to_shadow((void *)addr + size - 1) + 1);
 242
 243         if (unlikely(ret)) {
 244                 unsigned long last_byte = addr + size - 1;
 245                 s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
 246
 247                 if (unlikely(ret != (unsigned long)last_shadow ||
 248                         ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
 249                         return true;
 250         }
 251         return false;
 252 }
 253
 254 static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
 255 {
 256         if (__builtin_constant_p(size)) {
 257                 switch (size) {
 258                 case 1:
 259                         return memory_is_poisoned_1(addr);
 260                 case 2:
 261                         return memory_is_poisoned_2(addr);
 262                 case 4:
 263                         return memory_is_poisoned_4(addr);
 264                 case 8:
 265                         return memory_is_poisoned_8(addr);
 266                 case 16:
 267                         return memory_is_poisoned_16(addr);
 268                 default:
 269                         BUILD_BUG();
 270                 }
 271         }
 272
 273         return memory_is_poisoned_n(addr, size);
 274 }
 275
 276
 277 static __always_inline void check_memory_region(unsigned long addr,
 278                                                 size_t size, bool write)
 279 {
 280         if (unlikely(size == 0))
 281                 return;
 282
 283         if (unlikely((void *)addr <
 284                 kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
 285                 kasan_report(addr, size, write, _RET_IP_);
 286                 return;
 287         }
 288
 289         if (likely(!memory_is_poisoned(addr, size)))
 290                 return;
 291
 292         kasan_report(addr, size, write, _RET_IP_);
 293 }
 294
 295 void __asan_loadN(unsigned long addr, size_t size);
 296 void __asan_storeN(unsigned long addr, size_t size);
 297
 298 #undef memset
 299 void *memset(void *addr, int c, size_t len)
 300 {
 301         __asan_storeN((unsigned long)addr, len);
 302
 303         return __memset(addr, c, len);
 304 }
 305
 306 #undef memmove
 307 void *memmove(void *dest, const void *src, size_t len)
 308 {
 309         __asan_loadN((unsigned long)src, len);
 310         __asan_storeN((unsigned long)dest, len);
 311
 312         return __memmove(dest, src, len);
 313 }
 314
 315 #undef memcpy
 316 void *memcpy(void *dest, const void *src, size_t len)
 317 {
 318         __asan_loadN((unsigned long)src, len);
 319         __asan_storeN((unsigned long)dest, len);
 320
 321         return __memcpy(dest, src, len);
 322 }
 323
 324 void kasan_alloc_pages(struct page *page, unsigned int order)
 325 {
 326         if (likely(!PageHighMem(page)))
 327                 kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
 328 }
 329
 330 void kasan_free_pages(struct page *page, unsigned int order)
 331 {
 332         if (likely(!PageHighMem(page)))
 333                 kasan_poison_shadow(page_address(page),
 334                                 PAGE_SIZE << order,
 335                                 KASAN_FREE_PAGE);
 336 }
 337
 338 #ifdef CONFIG_SLAB
 339 /*
 340  * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
 341  * For larger allocations larger redzones are used.
 342  */
 343 static size_t optimal_redzone(size_t object_size)
 344 {
 345         int rz =
 346                 object_size <= 64        - 16   ? 16 :
 347                 object_size <= 128       - 32   ? 32 :
 348                 object_size <= 512       - 64   ? 64 :
 349                 object_size <= 4096      - 128  ? 128 :
 350                 object_size <= (1 << 14) - 256  ? 256 :
 351                 object_size <= (1 << 15) - 512  ? 512 :
 352                 object_size <= (1 << 16) - 1024 ? 1024 : 2048;
 353         return rz;
 354 }
 355
 356 void kasan_cache_create(struct kmem_cache *cache, size_t *size,
 357                         unsigned long *flags)
 358 {
 359         int redzone_adjust;
 360         /* Make sure the adjusted size is still less than
 361          * KMALLOC_MAX_CACHE_SIZE.
 362          * TODO: this check is only useful for SLAB, but not SLUB. We'll need
 363          * to skip it for SLUB when it starts using kasan_cache_create().
 364          */
 365         if (*size > KMALLOC_MAX_CACHE_SIZE -
 366             sizeof(struct kasan_alloc_meta) -
 367             sizeof(struct kasan_free_meta))
 368                 return;
 369         *flags |= SLAB_KASAN;
 370         /* Add alloc meta. */
 371         cache->kasan_info.alloc_meta_offset = *size;
 372         *size += sizeof(struct kasan_alloc_meta);
 373
 374         /* Add free meta. */
 375         if (cache->flags & SLAB_DESTROY_BY_RCU || cache->ctor ||
 376             cache->object_size < sizeof(struct kasan_free_meta)) {
 377                 cache->kasan_info.free_meta_offset = *size;
 378                 *size += sizeof(struct kasan_free_meta);
 379         }
 380         redzone_adjust = optimal_redzone(cache->object_size) -
 381                 (*size - cache->object_size);
 382         if (redzone_adjust > 0)
 383                 *size += redzone_adjust;
 384         *size = min(KMALLOC_MAX_CACHE_SIZE,
 385                     max(*size,
 386                         cache->object_size +
 387                         optimal_redzone(cache->object_size)));
 388 }
 389 #endif
 390
 391 void kasan_poison_slab(struct page *page)
 392 {
 393         kasan_poison_shadow(page_address(page),
 394                         PAGE_SIZE << compound_order(page),
 395                         KASAN_KMALLOC_REDZONE);
 396 }
 397
 398 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
 399 {
 400         kasan_unpoison_shadow(object, cache->object_size);
 401 }
 402
 403 void kasan_poison_object_data(struct kmem_cache *cache, void *object)
 404 {
 405         kasan_poison_shadow(object,
 406                         round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
 407                         KASAN_KMALLOC_REDZONE);
 408 #ifdef CONFIG_SLAB
 409         if (cache->flags & SLAB_KASAN) {
 410                 struct kasan_alloc_meta *alloc_info =
 411                         get_alloc_info(cache, object);
 412                 alloc_info->state = KASAN_STATE_INIT;
 413         }
 414 #endif
 415 }
 416
 417 #ifdef CONFIG_SLAB
 418 static inline int in_irqentry_text(unsigned long ptr)
 419 {
 420         return (ptr >= (unsigned long)&__irqentry_text_start &&
 421                 ptr < (unsigned long)&__irqentry_text_end) ||
 422                 (ptr >= (unsigned long)&__softirqentry_text_start &&
 423                  ptr < (unsigned long)&__softirqentry_text_end);
 424 }
 425
 426 static inline void filter_irq_stacks(struct stack_trace *trace)
 427 {
 428         int i;
 429
 430         if (!trace->nr_entries)
 431                 return;
 432         for (i = 0; i < trace->nr_entries; i++)
 433                 if (in_irqentry_text(trace->entries[i])) {
 434                         /* Include the irqentry function into the stack. */
 435                         trace->nr_entries = i + 1;
 436                         break;
 437                 }
 438 }
 439
 440 static inline depot_stack_handle_t save_stack(gfp_t flags)
 441 {
 442         unsigned long entries[KASAN_STACK_DEPTH];
 443         struct stack_trace trace = {
 444                 .nr_entries = 0,
 445                 .entries = entries,
 446                 .max_entries = KASAN_STACK_DEPTH,
 447                 .skip = 0
 448         };
 449
 450         save_stack_trace(&trace);
 451         filter_irq_stacks(&trace);
 452         if (trace.nr_entries != 0 &&
 453             trace.entries[trace.nr_entries-1] == ULONG_MAX)
 454                 trace.nr_entries--;
 455
 456         return depot_save_stack(&trace, flags);
 457 }
 458
 459 static inline void set_track(struct kasan_track *track, gfp_t flags)
 460 {
 461         track->pid = current->pid;
 462         track->stack = save_stack(flags);
 463 }
 464
 465 struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
 466                                         const void *object)
 467 {
 468         BUILD_BUG_ON(sizeof(struct kasan_alloc_meta) > 32);
 469         return (void *)object + cache->kasan_info.alloc_meta_offset;
 470 }
 471
 472 struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
 473                                       const void *object)
 474 {
 475         BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
 476         return (void *)object + cache->kasan_info.free_meta_offset;
 477 }
 478 #endif
 479
 480 void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
 481 {
 482         kasan_kmalloc(cache, object, cache->object_size, flags);
 483 }
 484
 485 void kasan_slab_free(struct kmem_cache *cache, void *object)
 486 {
 487         unsigned long size = cache->object_size;
 488         unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
 489
 490         /* RCU slabs could be legally used after free within the RCU period */
 491         if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
 492                 return;
 493
 494 #ifdef CONFIG_SLAB
 495         if (cache->flags & SLAB_KASAN) {
 496                 struct kasan_free_meta *free_info =
 497                         get_free_info(cache, object);
 498                 struct kasan_alloc_meta *alloc_info =
 499                         get_alloc_info(cache, object);
 500                 alloc_info->state = KASAN_STATE_FREE;
 501                 set_track(&free_info->track);
 502         }
 503 #endif
 504
 505         kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
 506 }
 507
 508 void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
 509                    gfp_t flags)
 510 {
 511         unsigned long redzone_start;
 512         unsigned long redzone_end;
 513
 514         if (unlikely(object == NULL))
 515                 return;
 516
 517         redzone_start = round_up((unsigned long)(object + size),
 518                                 KASAN_SHADOW_SCALE_SIZE);
 519         redzone_end = round_up((unsigned long)object + cache->object_size,
 520                                 KASAN_SHADOW_SCALE_SIZE);
 521
 522         kasan_unpoison_shadow(object, size);
 523         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 524                 KASAN_KMALLOC_REDZONE);
 525 #ifdef CONFIG_SLAB
 526         if (cache->flags & SLAB_KASAN) {
 527                 struct kasan_alloc_meta *alloc_info =
 528                         get_alloc_info(cache, object);
 529
 530                 alloc_info->state = KASAN_STATE_ALLOC;
 531                 alloc_info->alloc_size = size;
 532                 set_track(&alloc_info->track, flags);
 533         }
 534 #endif
 535 }
 536 EXPORT_SYMBOL(kasan_kmalloc);
 537
 538 void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
 539 {
 540         struct page *page;
 541         unsigned long redzone_start;
 542         unsigned long redzone_end;
 543
 544         if (unlikely(ptr == NULL))
 545                 return;
 546
 547         page = virt_to_page(ptr);
 548         redzone_start = round_up((unsigned long)(ptr + size),
 549                                 KASAN_SHADOW_SCALE_SIZE);
 550         redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
 551
 552         kasan_unpoison_shadow(ptr, size);
 553         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 554                 KASAN_PAGE_REDZONE);
 555 }
 556
 557 void kasan_krealloc(const void *object, size_t size, gfp_t flags)
 558 {
 559         struct page *page;
 560
 561         if (unlikely(object == ZERO_SIZE_PTR))
 562                 return;
 563
 564         page = virt_to_head_page(object);
 565
 566         if (unlikely(!PageSlab(page)))
 567                 kasan_kmalloc_large(object, size, flags);
 568         else
 569                 kasan_kmalloc(page->slab_cache, object, size, flags);
 570 }
 571
 572 void kasan_kfree(void *ptr)
 573 {
 574         struct page *page;
 575
 576         page = virt_to_head_page(ptr);
 577
 578         if (unlikely(!PageSlab(page)))
 579                 kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
 580                                 KASAN_FREE_PAGE);
 581         else
 582                 kasan_slab_free(page->slab_cache, ptr);
 583 }
 584
 585 void kasan_kfree_large(const void *ptr)
 586 {
 587         struct page *page = virt_to_page(ptr);
 588
 589         kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
 590                         KASAN_FREE_PAGE);
 591 }
 592
 593 int kasan_module_alloc(void *addr, size_t size)
 594 {
 595         void *ret;
 596         size_t shadow_size;
 597         unsigned long shadow_start;
 598
 599         shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
 600         shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
 601                         PAGE_SIZE);
 602
 603         if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
 604                 return -EINVAL;
 605
 606         ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
 607                         shadow_start + shadow_size,
 608                         GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
 609                         PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
 610                         __builtin_return_address(0));
 611
 612         if (ret) {
 613                 find_vm_area(addr)->flags |= VM_KASAN;
 614                 kmemleak_ignore(ret);
 615                 return 0;
 616         }
 617
 618         return -ENOMEM;
 619 }
 620
 621 void kasan_free_shadow(const struct vm_struct *vm)
 622 {
 623         if (vm->flags & VM_KASAN)
 624                 vfree(kasan_mem_to_shadow(vm->addr));
 625 }
 626
 627 static void register_global(struct kasan_global *global)
 628 {
 629         size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
 630
 631         kasan_unpoison_shadow(global->beg, global->size);
 632
 633         kasan_poison_shadow(global->beg + aligned_size,
 634                 global->size_with_redzone - aligned_size,
 635                 KASAN_GLOBAL_REDZONE);
 636 }
 637
 638 void __asan_register_globals(struct kasan_global *globals, size_t size)
 639 {
 640         int i;
 641
 642         for (i = 0; i < size; i++)
 643                 register_global(&globals[i]);
 644 }
 645 EXPORT_SYMBOL(__asan_register_globals);
 646
 647 void __asan_unregister_globals(struct kasan_global *globals, size_t size)
 648 {
 649 }
 650 EXPORT_SYMBOL(__asan_unregister_globals);
 651
 652 #define DEFINE_ASAN_LOAD_STORE(size)                            \
 653         void __asan_load##size(unsigned long addr)              \
 654         {                                                       \
 655                 check_memory_region(addr, size, false);         \
 656         }                                                       \
 657         EXPORT_SYMBOL(__asan_load##size);                       \
 658         __alias(__asan_load##size)                              \
 659         void __asan_load##size##_noabort(unsigned long);        \
 660         EXPORT_SYMBOL(__asan_load##size##_noabort);             \
 661         void __asan_store##size(unsigned long addr)             \
 662         {                                                       \
 663                 check_memory_region(addr, size, true);          \
 664         }                                                       \
 665         EXPORT_SYMBOL(__asan_store##size);                      \
 666         __alias(__asan_store##size)                             \
 667         void __asan_store##size##_noabort(unsigned long);       \
 668         EXPORT_SYMBOL(__asan_store##size##_noabort)
 669
 670 DEFINE_ASAN_LOAD_STORE(1);
 671 DEFINE_ASAN_LOAD_STORE(2);
 672 DEFINE_ASAN_LOAD_STORE(4);
 673 DEFINE_ASAN_LOAD_STORE(8);
 674 DEFINE_ASAN_LOAD_STORE(16);
 675
 676 void __asan_loadN(unsigned long addr, size_t size)
 677 {
 678         check_memory_region(addr, size, false);
 679 }
 680 EXPORT_SYMBOL(__asan_loadN);
 681
 682 __alias(__asan_loadN)
 683 void __asan_loadN_noabort(unsigned long, size_t);
 684 EXPORT_SYMBOL(__asan_loadN_noabort);
 685
 686 void __asan_storeN(unsigned long addr, size_t size)
 687 {
 688         check_memory_region(addr, size, true);
 689 }
 690 EXPORT_SYMBOL(__asan_storeN);
 691
 692 __alias(__asan_storeN)
 693 void __asan_storeN_noabort(unsigned long, size_t);
 694 EXPORT_SYMBOL(__asan_storeN_noabort);
 695
 696 /* to shut up compiler complaints */
 697 void __asan_handle_no_return(void) {}
 698 EXPORT_SYMBOL(__asan_handle_no_return);
 699
 700 #ifdef CONFIG_MEMORY_HOTPLUG
 701 static int kasan_mem_notifier(struct notifier_block *nb,
 702                         unsigned long action, void *data)
 703 {
 704         return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
 705 }
 706
 707 static int __init kasan_memhotplug_init(void)
 708 {
 709         pr_err("WARNING: KASAN doesn't support memory hot-add\n");
 710         pr_err("Memory hot-add will be disabled\n");
 711
 712         hotplug_memory_notifier(kasan_mem_notifier, 0);
 713
 714         return 0;
 715 }
 716
 717 module_init(kasan_memhotplug_init);
 718 #endif