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