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 static __always_inline void check_memory_region_inline(unsigned long addr,
 277                                                 size_t size, bool write,
 278                                                 unsigned long ret_ip)
 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 static void check_memory_region(unsigned long addr,
 296                                 size_t size, bool write,
 297                                 unsigned long ret_ip)
 298 {
 299         check_memory_region_inline(addr, size, write, ret_ip);
 300 }
 301
 302 void kasan_check_read(const void *p, unsigned int size)
 303 {
 304         check_memory_region((unsigned long)p, size, false, _RET_IP_);
 305 }
 306 EXPORT_SYMBOL(kasan_check_read);
 307
 308 void kasan_check_write(const void *p, unsigned int size)
 309 {
 310         check_memory_region((unsigned long)p, size, true, _RET_IP_);
 311 }
 312 EXPORT_SYMBOL(kasan_check_write);
 313
 314 #undef memset
 315 void *memset(void *addr, int c, size_t len)
 316 {
 317         check_memory_region((unsigned long)addr, len, true, _RET_IP_);
 318
 319         return __memset(addr, c, len);
 320 }
 321
 322 #undef memmove
 323 void *memmove(void *dest, const void *src, size_t len)
 324 {
 325         check_memory_region((unsigned long)src, len, false, _RET_IP_);
 326         check_memory_region((unsigned long)dest, len, true, _RET_IP_);
 327
 328         return __memmove(dest, src, len);
 329 }
 330
 331 #undef memcpy
 332 void *memcpy(void *dest, const void *src, size_t len)
 333 {
 334         check_memory_region((unsigned long)src, len, false, _RET_IP_);
 335         check_memory_region((unsigned long)dest, len, true, _RET_IP_);
 336
 337         return __memcpy(dest, src, len);
 338 }
 339
 340 void kasan_alloc_pages(struct page *page, unsigned int order)
 341 {
 342         if (likely(!PageHighMem(page)))
 343                 kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
 344 }
 345
 346 void kasan_free_pages(struct page *page, unsigned int order)
 347 {
 348         if (likely(!PageHighMem(page)))
 349                 kasan_poison_shadow(page_address(page),
 350                                 PAGE_SIZE << order,
 351                                 KASAN_FREE_PAGE);
 352 }
 353
 354 /*
 355  * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
 356  * For larger allocations larger redzones are used.
 357  */
 358 static size_t optimal_redzone(size_t object_size)
 359 {
 360         int rz =
 361                 object_size <= 64        - 16   ? 16 :
 362                 object_size <= 128       - 32   ? 32 :
 363                 object_size <= 512       - 64   ? 64 :
 364                 object_size <= 4096      - 128  ? 128 :
 365                 object_size <= (1 << 14) - 256  ? 256 :
 366                 object_size <= (1 << 15) - 512  ? 512 :
 367                 object_size <= (1 << 16) - 1024 ? 1024 : 2048;
 368         return rz;
 369 }
 370
 371 void kasan_cache_create(struct kmem_cache *cache, size_t *size,
 372                         unsigned long *flags)
 373 {
 374         int redzone_adjust;
 375         int orig_size = *size;
 376
 377         /* Add alloc meta. */
 378         cache->kasan_info.alloc_meta_offset = *size;
 379         *size += sizeof(struct kasan_alloc_meta);
 380
 381         /* Add free meta. */
 382         if (cache->flags & SLAB_DESTROY_BY_RCU || cache->ctor ||
 383             cache->object_size < sizeof(struct kasan_free_meta)) {
 384                 cache->kasan_info.free_meta_offset = *size;
 385                 *size += sizeof(struct kasan_free_meta);
 386         }
 387         redzone_adjust = optimal_redzone(cache->object_size) -
 388                 (*size - cache->object_size);
 389
 390         if (redzone_adjust > 0)
 391                 *size += redzone_adjust;
 392
 393         *size = min(KMALLOC_MAX_SIZE, max(*size, cache->object_size +
 394                                         optimal_redzone(cache->object_size)));
 395
 396         /*
 397          * If the metadata doesn't fit, don't enable KASAN at all.
 398          */
 399         if (*size <= cache->kasan_info.alloc_meta_offset ||
 400                         *size <= cache->kasan_info.free_meta_offset) {
 401                 cache->kasan_info.alloc_meta_offset = 0;
 402                 cache->kasan_info.free_meta_offset = 0;
 403                 *size = orig_size;
 404                 return;
 405         }
 406
 407         *flags |= SLAB_KASAN;
 408 }
 409
 410 void kasan_cache_shrink(struct kmem_cache *cache)
 411 {
 412         quarantine_remove_cache(cache);
 413 }
 414
 415 void kasan_cache_destroy(struct kmem_cache *cache)
 416 {
 417         quarantine_remove_cache(cache);
 418 }
 419
 420 size_t kasan_metadata_size(struct kmem_cache *cache)
 421 {
 422         return (cache->kasan_info.alloc_meta_offset ?
 423                 sizeof(struct kasan_alloc_meta) : 0) +
 424                 (cache->kasan_info.free_meta_offset ?
 425                 sizeof(struct kasan_free_meta) : 0);
 426 }
 427
 428 void kasan_poison_slab(struct page *page)
 429 {
 430         kasan_poison_shadow(page_address(page),
 431                         PAGE_SIZE << compound_order(page),
 432                         KASAN_KMALLOC_REDZONE);
 433 }
 434
 435 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
 436 {
 437         kasan_unpoison_shadow(object, cache->object_size);
 438 }
 439
 440 void kasan_poison_object_data(struct kmem_cache *cache, void *object)
 441 {
 442         kasan_poison_shadow(object,
 443                         round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
 444                         KASAN_KMALLOC_REDZONE);
 445 }
 446
 447 static inline int in_irqentry_text(unsigned long ptr)
 448 {
 449         return (ptr >= (unsigned long)&__irqentry_text_start &&
 450                 ptr < (unsigned long)&__irqentry_text_end) ||
 451                 (ptr >= (unsigned long)&__softirqentry_text_start &&
 452                  ptr < (unsigned long)&__softirqentry_text_end);
 453 }
 454
 455 static inline void filter_irq_stacks(struct stack_trace *trace)
 456 {
 457         int i;
 458
 459         if (!trace->nr_entries)
 460                 return;
 461         for (i = 0; i < trace->nr_entries; i++)
 462                 if (in_irqentry_text(trace->entries[i])) {
 463                         /* Include the irqentry function into the stack. */
 464                         trace->nr_entries = i + 1;
 465                         break;
 466                 }
 467 }
 468
 469 static inline depot_stack_handle_t save_stack(gfp_t flags)
 470 {
 471         unsigned long entries[KASAN_STACK_DEPTH];
 472         struct stack_trace trace = {
 473                 .nr_entries = 0,
 474                 .entries = entries,
 475                 .max_entries = KASAN_STACK_DEPTH,
 476                 .skip = 0
 477         };
 478
 479         save_stack_trace(&trace);
 480         filter_irq_stacks(&trace);
 481         if (trace.nr_entries != 0 &&
 482             trace.entries[trace.nr_entries-1] == ULONG_MAX)
 483                 trace.nr_entries--;
 484
 485         return depot_save_stack(&trace, flags);
 486 }
 487
 488 static inline void set_track(struct kasan_track *track, gfp_t flags)
 489 {
 490         track->pid = current->pid;
 491         track->stack = save_stack(flags);
 492 }
 493
 494 struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
 495                                         const void *object)
 496 {
 497         BUILD_BUG_ON(sizeof(struct kasan_alloc_meta) > 32);
 498         return (void *)object + cache->kasan_info.alloc_meta_offset;
 499 }
 500
 501 struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
 502                                       const void *object)
 503 {
 504         BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
 505         return (void *)object + cache->kasan_info.free_meta_offset;
 506 }
 507
 508 void kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
 509 {
 510         struct kasan_alloc_meta *alloc_info;
 511
 512         if (!(cache->flags & SLAB_KASAN))
 513                 return;
 514
 515         alloc_info = get_alloc_info(cache, object);
 516         __memset(alloc_info, 0, sizeof(*alloc_info));
 517 }
 518
 519 void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
 520 {
 521         kasan_kmalloc(cache, object, cache->object_size, flags);
 522 }
 523
 524 static void kasan_poison_slab_free(struct kmem_cache *cache, void *object)
 525 {
 526         unsigned long size = cache->object_size;
 527         unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
 528
 529         /* RCU slabs could be legally used after free within the RCU period */
 530         if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
 531                 return;
 532
 533         kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
 534 }
 535
 536 bool kasan_slab_free(struct kmem_cache *cache, void *object)
 537 {
 538         s8 shadow_byte;
 539
 540         /* RCU slabs could be legally used after free within the RCU period */
 541         if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
 542                 return false;
 543
 544         shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));
 545         if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {
 546                 kasan_report_double_free(cache, object, shadow_byte);
 547                 return true;
 548         }
 549
 550         kasan_poison_slab_free(cache, object);
 551
 552         if (unlikely(!(cache->flags & SLAB_KASAN)))
 553                 return false;
 554
 555         set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT);
 556         quarantine_put(get_free_info(cache, object), cache);
 557         return true;
 558 }
 559
 560 void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
 561                    gfp_t flags)
 562 {
 563         unsigned long redzone_start;
 564         unsigned long redzone_end;
 565
 566         if (gfpflags_allow_blocking(flags))
 567                 quarantine_reduce();
 568
 569         if (unlikely(object == NULL))
 570                 return;
 571
 572         redzone_start = round_up((unsigned long)(object + size),
 573                                 KASAN_SHADOW_SCALE_SIZE);
 574         redzone_end = round_up((unsigned long)object + cache->object_size,
 575                                 KASAN_SHADOW_SCALE_SIZE);
 576
 577         kasan_unpoison_shadow(object, size);
 578         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 579                 KASAN_KMALLOC_REDZONE);
 580
 581         if (cache->flags & SLAB_KASAN)
 582                 set_track(&get_alloc_info(cache, object)->alloc_track, flags);
 583 }
 584 EXPORT_SYMBOL(kasan_kmalloc);
 585
 586 void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
 587 {
 588         struct page *page;
 589         unsigned long redzone_start;
 590         unsigned long redzone_end;
 591
 592         if (gfpflags_allow_blocking(flags))
 593                 quarantine_reduce();
 594
 595         if (unlikely(ptr == NULL))
 596                 return;
 597
 598         page = virt_to_page(ptr);
 599         redzone_start = round_up((unsigned long)(ptr + size),
 600                                 KASAN_SHADOW_SCALE_SIZE);
 601         redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
 602
 603         kasan_unpoison_shadow(ptr, size);
 604         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 605                 KASAN_PAGE_REDZONE);
 606 }
 607
 608 void kasan_krealloc(const void *object, size_t size, gfp_t flags)
 609 {
 610         struct page *page;
 611
 612         if (unlikely(object == ZERO_SIZE_PTR))
 613                 return;
 614
 615         page = virt_to_head_page(object);
 616
 617         if (unlikely(!PageSlab(page)))
 618                 kasan_kmalloc_large(object, size, flags);
 619         else
 620                 kasan_kmalloc(page->slab_cache, object, size, flags);
 621 }
 622
 623 void kasan_poison_kfree(void *ptr)
 624 {
 625         struct page *page;
 626
 627         page = virt_to_head_page(ptr);
 628
 629         if (unlikely(!PageSlab(page)))
 630                 kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
 631                                 KASAN_FREE_PAGE);
 632         else
 633                 kasan_poison_slab_free(page->slab_cache, ptr);
 634 }
 635
 636 void kasan_kfree_large(const void *ptr)
 637 {
 638         struct page *page = virt_to_page(ptr);
 639
 640         kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
 641                         KASAN_FREE_PAGE);
 642 }
 643
 644 int kasan_module_alloc(void *addr, size_t size)
 645 {
 646         void *ret;
 647         size_t shadow_size;
 648         unsigned long shadow_start;
 649
 650         shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
 651         shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
 652                         PAGE_SIZE);
 653
 654         if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
 655                 return -EINVAL;
 656
 657         ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
 658                         shadow_start + shadow_size,
 659                         GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
 660                         PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
 661                         __builtin_return_address(0));
 662
 663         if (ret) {
 664                 find_vm_area(addr)->flags |= VM_KASAN;
 665                 kmemleak_ignore(ret);
 666                 return 0;
 667         }
 668
 669         return -ENOMEM;
 670 }
 671
 672 void kasan_free_shadow(const struct vm_struct *vm)
 673 {
 674         if (vm->flags & VM_KASAN)
 675                 vfree(kasan_mem_to_shadow(vm->addr));
 676 }
 677
 678 static void register_global(struct kasan_global *global)
 679 {
 680         size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
 681
 682         kasan_unpoison_shadow(global->beg, global->size);
 683
 684         kasan_poison_shadow(global->beg + aligned_size,
 685                 global->size_with_redzone - aligned_size,
 686                 KASAN_GLOBAL_REDZONE);
 687 }
 688
 689 void __asan_register_globals(struct kasan_global *globals, size_t size)
 690 {
 691         int i;
 692
 693         for (i = 0; i < size; i++)
 694                 register_global(&globals[i]);
 695 }
 696 EXPORT_SYMBOL(__asan_register_globals);
 697
 698 void __asan_unregister_globals(struct kasan_global *globals, size_t size)
 699 {
 700 }
 701 EXPORT_SYMBOL(__asan_unregister_globals);
 702
 703 #define DEFINE_ASAN_LOAD_STORE(size)                                    \
 704         void __asan_load##size(unsigned long addr)                      \
 705         {                                                               \
 706                 check_memory_region_inline(addr, size, false, _RET_IP_);\
 707         }                                                               \
 708         EXPORT_SYMBOL(__asan_load##size);                               \
 709         __alias(__asan_load##size)                                      \
 710         void __asan_load##size##_noabort(unsigned long);                \
 711         EXPORT_SYMBOL(__asan_load##size##_noabort);                     \
 712         void __asan_store##size(unsigned long addr)                     \
 713         {                                                               \
 714                 check_memory_region_inline(addr, size, true, _RET_IP_); \
 715         }                                                               \
 716         EXPORT_SYMBOL(__asan_store##size);                              \
 717         __alias(__asan_store##size)                                     \
 718         void __asan_store##size##_noabort(unsigned long);               \
 719         EXPORT_SYMBOL(__asan_store##size##_noabort)
 720
 721 DEFINE_ASAN_LOAD_STORE(1);
 722 DEFINE_ASAN_LOAD_STORE(2);
 723 DEFINE_ASAN_LOAD_STORE(4);
 724 DEFINE_ASAN_LOAD_STORE(8);
 725 DEFINE_ASAN_LOAD_STORE(16);
 726
 727 void __asan_loadN(unsigned long addr, size_t size)
 728 {
 729         check_memory_region(addr, size, false, _RET_IP_);
 730 }
 731 EXPORT_SYMBOL(__asan_loadN);
 732
 733 __alias(__asan_loadN)
 734 void __asan_loadN_noabort(unsigned long, size_t);
 735 EXPORT_SYMBOL(__asan_loadN_noabort);
 736
 737 void __asan_storeN(unsigned long addr, size_t size)
 738 {
 739         check_memory_region(addr, size, true, _RET_IP_);
 740 }
 741 EXPORT_SYMBOL(__asan_storeN);
 742
 743 __alias(__asan_storeN)
 744 void __asan_storeN_noabort(unsigned long, size_t);
 745 EXPORT_SYMBOL(__asan_storeN_noabort);
 746
 747 /* to shut up compiler complaints */
 748 void __asan_handle_no_return(void) {}
 749 EXPORT_SYMBOL(__asan_handle_no_return);
 750
 751 #ifdef CONFIG_MEMORY_HOTPLUG
 752 static int kasan_mem_notifier(struct notifier_block *nb,
 753                         unsigned long action, void *data)
 754 {
 755         return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
 756 }
 757
 758 static int __init kasan_memhotplug_init(void)
 759 {
 760         pr_info("WARNING: KASAN doesn't support memory hot-add\n");
 761         pr_info("Memory hot-add will be disabled\n");
 762
 763         hotplug_memory_notifier(kasan_mem_notifier, 0);
 764
 765         return 0;
 766 }
 767
 768 module_init(kasan_memhotplug_init);
 769 #endif