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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#include <linux/bug.h>
38
39#include "kasan.h"
40#include "../slab.h"
41
42/*
43 * Poisons the shadow memory for 'size' bytes starting from 'addr'.
44 * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
45 */
46static void kasan_poison_shadow(const void *address, size_t size, u8 value)
47{
48 void *shadow_start, *shadow_end;
49
50 shadow_start = kasan_mem_to_shadow(address);
51 shadow_end = kasan_mem_to_shadow(address + size);
52
53 memset(shadow_start, value, shadow_end - shadow_start);
54}
55
56void kasan_unpoison_shadow(const void *address, size_t size)
57{
58 kasan_poison_shadow(address, size, 0);
59
60 if (size & KASAN_SHADOW_MASK) {
61 u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
62 *shadow = size & KASAN_SHADOW_MASK;
63 }
64}
65
66static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
67{
68 void *base = task_stack_page(task);
69 size_t size = sp - base;
70
71 kasan_unpoison_shadow(base, size);
72}
73
74/* Unpoison the entire stack for a task. */
75void kasan_unpoison_task_stack(struct task_struct *task)
76{
77 __kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE);
78}
79
80/* Unpoison the stack for the current task beyond a watermark sp value. */
81asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
82{
83 /*
84 * Calculate the task stack base address. Avoid using 'current'
85 * because this function is called by early resume code which hasn't
86 * yet set up the percpu register (%gs).
87 */
88 void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
89
90 kasan_unpoison_shadow(base, watermark - base);
91}
92
93/*
94 * Clear all poison for the region between the current SP and a provided
95 * watermark value, as is sometimes required prior to hand-crafted asm function
96 * returns in the middle of functions.
97 */
98void kasan_unpoison_stack_above_sp_to(const void *watermark)
99{
100 const void *sp = __builtin_frame_address(0);
101 size_t size = watermark - sp;
102
103 if (WARN_ON(sp > watermark))
104 return;
105 kasan_unpoison_shadow(sp, size);
106}
107
108/*
109 * All functions below always inlined so compiler could
110 * perform better optimizations in each of __asan_loadX/__assn_storeX
111 * depending on memory access size X.
112 */
113
114static __always_inline bool memory_is_poisoned_1(unsigned long addr)
115{
116 s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
117
118 if (unlikely(shadow_value)) {
119 s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
120 return unlikely(last_accessible_byte >= shadow_value);
121 }
122
123 return false;
124}
125
126static __always_inline bool memory_is_poisoned_2(unsigned long addr)
127{
128 u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
129
130 if (unlikely(*shadow_addr)) {
131 if (memory_is_poisoned_1(addr + 1))
132 return true;
133
134 /*
135 * If single shadow byte covers 2-byte access, we don't
136 * need to do anything more. Otherwise, test the first
137 * shadow byte.
138 */
139 if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
140 return false;
141
142 return unlikely(*(u8 *)shadow_addr);
143 }
144
145 return false;
146}
147
148static __always_inline bool memory_is_poisoned_4(unsigned long addr)
149{
150 u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
151
152 if (unlikely(*shadow_addr)) {
153 if (memory_is_poisoned_1(addr + 3))
154 return true;
155
156 /*
157 * If single shadow byte covers 4-byte access, we don't
158 * need to do anything more. Otherwise, test the first
159 * shadow byte.
160 */
161 if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
162 return false;
163
164 return unlikely(*(u8 *)shadow_addr);
165 }
166
167 return false;
168}
169
170static __always_inline bool memory_is_poisoned_8(unsigned long addr)
171{
172 u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
173
174 if (unlikely(*shadow_addr)) {
175 if (memory_is_poisoned_1(addr + 7))
176 return true;
177
178 /*
179 * If single shadow byte covers 8-byte access, we don't
180 * need to do anything more. Otherwise, test the first
181 * shadow byte.
182 */
183 if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
184 return false;
185
186 return unlikely(*(u8 *)shadow_addr);
187 }
188
189 return false;
190}
191
192static __always_inline bool memory_is_poisoned_16(unsigned long addr)
193{
194 u32 *shadow_addr = (u32 *)kasan_mem_to_shadow((void *)addr);
195
196 if (unlikely(*shadow_addr)) {
197 u16 shadow_first_bytes = *(u16 *)shadow_addr;
198
199 if (unlikely(shadow_first_bytes))
200 return true;
201
202 /*
203 * If two shadow bytes covers 16-byte access, we don't
204 * need to do anything more. Otherwise, test the last
205 * shadow byte.
206 */
207 if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
208 return false;
209
210 return memory_is_poisoned_1(addr + 15);
211 }
212
213 return false;
214}
215
216static __always_inline unsigned long bytes_is_zero(const u8 *start,
217 size_t size)
218{
219 while (size) {
220 if (unlikely(*start))
221 return (unsigned long)start;
222 start++;
223 size--;
224 }
225
226 return 0;
227}
228
229static __always_inline unsigned long memory_is_zero(const void *start,
230 const void *end)
231{
232 unsigned int words;
233 unsigned long ret;
234 unsigned int prefix = (unsigned long)start % 8;
235
236 if (end - start <= 16)
237 return bytes_is_zero(start, end - start);
238
239 if (prefix) {
240 prefix = 8 - prefix;
241 ret = bytes_is_zero(start, prefix);
242 if (unlikely(ret))
243 return ret;
244 start += prefix;
245 }
246
247 words = (end - start) / 8;
248 while (words) {
249 if (unlikely(*(u64 *)start))
250 return bytes_is_zero(start, 8);
251 start += 8;
252 words--;
253 }
254
255 return bytes_is_zero(start, (end - start) % 8);
256}
257
258static __always_inline bool memory_is_poisoned_n(unsigned long addr,
259 size_t size)
260{
261 unsigned long ret;
262
263 ret = memory_is_zero(kasan_mem_to_shadow((void *)addr),
264 kasan_mem_to_shadow((void *)addr + size - 1) + 1);
265
266 if (unlikely(ret)) {
267 unsigned long last_byte = addr + size - 1;
268 s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
269
270 if (unlikely(ret != (unsigned long)last_shadow ||
271 ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
272 return true;
273 }
274 return false;
275}
276
277static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
278{
279 if (__builtin_constant_p(size)) {
280 switch (size) {
281 case 1:
282 return memory_is_poisoned_1(addr);
283 case 2:
284 return memory_is_poisoned_2(addr);
285 case 4:
286 return memory_is_poisoned_4(addr);
287 case 8:
288 return memory_is_poisoned_8(addr);
289 case 16:
290 return memory_is_poisoned_16(addr);
291 default:
292 BUILD_BUG();
293 }
294 }
295
296 return memory_is_poisoned_n(addr, size);
297}
298
299static __always_inline void check_memory_region_inline(unsigned long addr,
300 size_t size, bool write,
301 unsigned long ret_ip)
302{
303 if (unlikely(size == 0))
304 return;
305
306 if (unlikely((void *)addr <
307 kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
308 kasan_report(addr, size, write, ret_ip);
309 return;
310 }
311
312 if (likely(!memory_is_poisoned(addr, size)))
313 return;
314
315 kasan_report(addr, size, write, ret_ip);
316}
317
318static void check_memory_region(unsigned long addr,
319 size_t size, bool write,
320 unsigned long ret_ip)
321{
322 check_memory_region_inline(addr, size, write, ret_ip);
323}
324
325void kasan_check_read(const void *p, unsigned int size)
326{
327 check_memory_region((unsigned long)p, size, false, _RET_IP_);
328}
329EXPORT_SYMBOL(kasan_check_read);
330
331void kasan_check_write(const void *p, unsigned int size)
332{
333 check_memory_region((unsigned long)p, size, true, _RET_IP_);
334}
335EXPORT_SYMBOL(kasan_check_write);
336
337#undef memset
338void *memset(void *addr, int c, size_t len)
339{
340 check_memory_region((unsigned long)addr, len, true, _RET_IP_);
341
342 return __memset(addr, c, len);
343}
344
345#undef memmove
346void *memmove(void *dest, const void *src, size_t len)
347{
348 check_memory_region((unsigned long)src, len, false, _RET_IP_);
349 check_memory_region((unsigned long)dest, len, true, _RET_IP_);
350
351 return __memmove(dest, src, len);
352}
353
354#undef memcpy
355void *memcpy(void *dest, const void *src, size_t len)
356{
357 check_memory_region((unsigned long)src, len, false, _RET_IP_);
358 check_memory_region((unsigned long)dest, len, true, _RET_IP_);
359
360 return __memcpy(dest, src, len);
361}
362
363void kasan_alloc_pages(struct page *page, unsigned int order)
364{
365 if (likely(!PageHighMem(page)))
366 kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
367}
368
369void kasan_free_pages(struct page *page, unsigned int order)
370{
371 if (likely(!PageHighMem(page)))
372 kasan_poison_shadow(page_address(page),
373 PAGE_SIZE << order,
374 KASAN_FREE_PAGE);
375}
376
377/*
378 * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
379 * For larger allocations larger redzones are used.
380 */
381static size_t optimal_redzone(size_t object_size)
382{
383 int rz =
384 object_size <= 64 - 16 ? 16 :
385 object_size <= 128 - 32 ? 32 :
386 object_size <= 512 - 64 ? 64 :
387 object_size <= 4096 - 128 ? 128 :
388 object_size <= (1 << 14) - 256 ? 256 :
389 object_size <= (1 << 15) - 512 ? 512 :
390 object_size <= (1 << 16) - 1024 ? 1024 : 2048;
391 return rz;
392}
393
394void kasan_cache_create(struct kmem_cache *cache, size_t *size,
395 unsigned long *flags)
396{
397 int redzone_adjust;
398 int orig_size = *size;
399
400 /* Add alloc meta. */
401 cache->kasan_info.alloc_meta_offset = *size;
402 *size += sizeof(struct kasan_alloc_meta);
403
404 /* Add free meta. */
405 if (cache->flags & SLAB_DESTROY_BY_RCU || cache->ctor ||
406 cache->object_size < sizeof(struct kasan_free_meta)) {
407 cache->kasan_info.free_meta_offset = *size;
408 *size += sizeof(struct kasan_free_meta);
409 }
410 redzone_adjust = optimal_redzone(cache->object_size) -
411 (*size - cache->object_size);
412
413 if (redzone_adjust > 0)
414 *size += redzone_adjust;
415
416 *size = min(KMALLOC_MAX_SIZE, max(*size, cache->object_size +
417 optimal_redzone(cache->object_size)));
418
419 /*
420 * If the metadata doesn't fit, don't enable KASAN at all.
421 */
422 if (*size <= cache->kasan_info.alloc_meta_offset ||
423 *size <= cache->kasan_info.free_meta_offset) {
424 cache->kasan_info.alloc_meta_offset = 0;
425 cache->kasan_info.free_meta_offset = 0;
426 *size = orig_size;
427 return;
428 }
429
430 *flags |= SLAB_KASAN;
431}
432
433void kasan_cache_shrink(struct kmem_cache *cache)
434{
435 quarantine_remove_cache(cache);
436}
437
438void kasan_cache_destroy(struct kmem_cache *cache)
439{
440 quarantine_remove_cache(cache);
441}
442
443size_t kasan_metadata_size(struct kmem_cache *cache)
444{
445 return (cache->kasan_info.alloc_meta_offset ?
446 sizeof(struct kasan_alloc_meta) : 0) +
447 (cache->kasan_info.free_meta_offset ?
448 sizeof(struct kasan_free_meta) : 0);
449}
450
451void kasan_poison_slab(struct page *page)
452{
453 kasan_poison_shadow(page_address(page),
454 PAGE_SIZE << compound_order(page),
455 KASAN_KMALLOC_REDZONE);
456}
457
458void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
459{
460 kasan_unpoison_shadow(object, cache->object_size);
461}
462
463void kasan_poison_object_data(struct kmem_cache *cache, void *object)
464{
465 kasan_poison_shadow(object,
466 round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
467 KASAN_KMALLOC_REDZONE);
468}
469
470static inline int in_irqentry_text(unsigned long ptr)
471{
472 return (ptr >= (unsigned long)&__irqentry_text_start &&
473 ptr < (unsigned long)&__irqentry_text_end) ||
474 (ptr >= (unsigned long)&__softirqentry_text_start &&
475 ptr < (unsigned long)&__softirqentry_text_end);
476}
477
478static inline void filter_irq_stacks(struct stack_trace *trace)
479{
480 int i;
481
482 if (!trace->nr_entries)
483 return;
484 for (i = 0; i < trace->nr_entries; i++)
485 if (in_irqentry_text(trace->entries[i])) {
486 /* Include the irqentry function into the stack. */
487 trace->nr_entries = i + 1;
488 break;
489 }
490}
491
492static inline depot_stack_handle_t save_stack(gfp_t flags)
493{
494 unsigned long entries[KASAN_STACK_DEPTH];
495 struct stack_trace trace = {
496 .nr_entries = 0,
497 .entries = entries,
498 .max_entries = KASAN_STACK_DEPTH,
499 .skip = 0
500 };
501
502 save_stack_trace(&trace);
503 filter_irq_stacks(&trace);
504 if (trace.nr_entries != 0 &&
505 trace.entries[trace.nr_entries-1] == ULONG_MAX)
506 trace.nr_entries--;
507
508 return depot_save_stack(&trace, flags);
509}
510
511static inline void set_track(struct kasan_track *track, gfp_t flags)
512{
513 track->pid = current->pid;
514 track->stack = save_stack(flags);
515}
516
517struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
518 const void *object)
519{
520 BUILD_BUG_ON(sizeof(struct kasan_alloc_meta) > 32);
521 return (void *)object + cache->kasan_info.alloc_meta_offset;
522}
523
524struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
525 const void *object)
526{
527 BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
528 return (void *)object + cache->kasan_info.free_meta_offset;
529}
530
531void kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
532{
533 struct kasan_alloc_meta *alloc_info;
534
535 if (!(cache->flags & SLAB_KASAN))
536 return;
537
538 alloc_info = get_alloc_info(cache, object);
539 __memset(alloc_info, 0, sizeof(*alloc_info));
540}
541
542void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
543{
544 kasan_kmalloc(cache, object, cache->object_size, flags);
545}
546
547static void kasan_poison_slab_free(struct kmem_cache *cache, void *object)
548{
549 unsigned long size = cache->object_size;
550 unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
551
552 /* RCU slabs could be legally used after free within the RCU period */
553 if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
554 return;
555
556 kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
557}
558
559bool kasan_slab_free(struct kmem_cache *cache, void *object)
560{
561 s8 shadow_byte;
562
563 /* RCU slabs could be legally used after free within the RCU period */
564 if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
565 return false;
566
567 shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));
568 if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {
569 kasan_report_double_free(cache, object, shadow_byte);
570 return true;
571 }
572
573 kasan_poison_slab_free(cache, object);
574
575 if (unlikely(!(cache->flags & SLAB_KASAN)))
576 return false;
577
578 set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT);
579 quarantine_put(get_free_info(cache, object), cache);
580 return true;
581}
582
583void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
584 gfp_t flags)
585{
586 unsigned long redzone_start;
587 unsigned long redzone_end;
588
589 if (gfpflags_allow_blocking(flags))
590 quarantine_reduce();
591
592 if (unlikely(object == NULL))
593 return;
594
595 redzone_start = round_up((unsigned long)(object + size),
596 KASAN_SHADOW_SCALE_SIZE);
597 redzone_end = round_up((unsigned long)object + cache->object_size,
598 KASAN_SHADOW_SCALE_SIZE);
599
600 kasan_unpoison_shadow(object, size);
601 kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
602 KASAN_KMALLOC_REDZONE);
603
604 if (cache->flags & SLAB_KASAN)
605 set_track(&get_alloc_info(cache, object)->alloc_track, flags);
606}
607EXPORT_SYMBOL(kasan_kmalloc);
608
609void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
610{
611 struct page *page;
612 unsigned long redzone_start;
613 unsigned long redzone_end;
614
615 if (gfpflags_allow_blocking(flags))
616 quarantine_reduce();
617
618 if (unlikely(ptr == NULL))
619 return;
620
621 page = virt_to_page(ptr);
622 redzone_start = round_up((unsigned long)(ptr + size),
623 KASAN_SHADOW_SCALE_SIZE);
624 redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
625
626 kasan_unpoison_shadow(ptr, size);
627 kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
628 KASAN_PAGE_REDZONE);
629}
630
631void kasan_krealloc(const void *object, size_t size, gfp_t flags)
632{
633 struct page *page;
634
635 if (unlikely(object == ZERO_SIZE_PTR))
636 return;
637
638 page = virt_to_head_page(object);
639
640 if (unlikely(!PageSlab(page)))
641 kasan_kmalloc_large(object, size, flags);
642 else
643 kasan_kmalloc(page->slab_cache, object, size, flags);
644}
645
646void kasan_poison_kfree(void *ptr)
647{
648 struct page *page;
649
650 page = virt_to_head_page(ptr);
651
652 if (unlikely(!PageSlab(page)))
653 kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
654 KASAN_FREE_PAGE);
655 else
656 kasan_poison_slab_free(page->slab_cache, ptr);
657}
658
659void kasan_kfree_large(const void *ptr)
660{
661 struct page *page = virt_to_page(ptr);
662
663 kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
664 KASAN_FREE_PAGE);
665}
666
667int kasan_module_alloc(void *addr, size_t size)
668{
669 void *ret;
670 size_t shadow_size;
671 unsigned long shadow_start;
672
673 shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
674 shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
675 PAGE_SIZE);
676
677 if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
678 return -EINVAL;
679
680 ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
681 shadow_start + shadow_size,
682 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
683 PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
684 __builtin_return_address(0));
685
686 if (ret) {
687 find_vm_area(addr)->flags |= VM_KASAN;
688 kmemleak_ignore(ret);
689 return 0;
690 }
691
692 return -ENOMEM;
693}
694
695void kasan_free_shadow(const struct vm_struct *vm)
696{
697 if (vm->flags & VM_KASAN)
698 vfree(kasan_mem_to_shadow(vm->addr));
699}
700
701static void register_global(struct kasan_global *global)
702{
703 size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
704
705 kasan_unpoison_shadow(global->beg, global->size);
706
707 kasan_poison_shadow(global->beg + aligned_size,
708 global->size_with_redzone - aligned_size,
709 KASAN_GLOBAL_REDZONE);
710}
711
712void __asan_register_globals(struct kasan_global *globals, size_t size)
713{
714 int i;
715
716 for (i = 0; i < size; i++)
717 register_global(&globals[i]);
718}
719EXPORT_SYMBOL(__asan_register_globals);
720
721void __asan_unregister_globals(struct kasan_global *globals, size_t size)
722{
723}
724EXPORT_SYMBOL(__asan_unregister_globals);
725
726#define DEFINE_ASAN_LOAD_STORE(size) \
727 void __asan_load##size(unsigned long addr) \
728 { \
729 check_memory_region_inline(addr, size, false, _RET_IP_);\
730 } \
731 EXPORT_SYMBOL(__asan_load##size); \
732 __alias(__asan_load##size) \
733 void __asan_load##size##_noabort(unsigned long); \
734 EXPORT_SYMBOL(__asan_load##size##_noabort); \
735 void __asan_store##size(unsigned long addr) \
736 { \
737 check_memory_region_inline(addr, size, true, _RET_IP_); \
738 } \
739 EXPORT_SYMBOL(__asan_store##size); \
740 __alias(__asan_store##size) \
741 void __asan_store##size##_noabort(unsigned long); \
742 EXPORT_SYMBOL(__asan_store##size##_noabort)
743
744DEFINE_ASAN_LOAD_STORE(1);
745DEFINE_ASAN_LOAD_STORE(2);
746DEFINE_ASAN_LOAD_STORE(4);
747DEFINE_ASAN_LOAD_STORE(8);
748DEFINE_ASAN_LOAD_STORE(16);
749
750void __asan_loadN(unsigned long addr, size_t size)
751{
752 check_memory_region(addr, size, false, _RET_IP_);
753}
754EXPORT_SYMBOL(__asan_loadN);
755
756__alias(__asan_loadN)
757void __asan_loadN_noabort(unsigned long, size_t);
758EXPORT_SYMBOL(__asan_loadN_noabort);
759
760void __asan_storeN(unsigned long addr, size_t size)
761{
762 check_memory_region(addr, size, true, _RET_IP_);
763}
764EXPORT_SYMBOL(__asan_storeN);
765
766__alias(__asan_storeN)
767void __asan_storeN_noabort(unsigned long, size_t);
768EXPORT_SYMBOL(__asan_storeN_noabort);
769
770/* to shut up compiler complaints */
771void __asan_handle_no_return(void) {}
772EXPORT_SYMBOL(__asan_handle_no_return);
773
774/* Emitted by compiler to poison large objects when they go out of scope. */
775void __asan_poison_stack_memory(const void *addr, size_t size)
776{
777 /*
778 * Addr is KASAN_SHADOW_SCALE_SIZE-aligned and the object is surrounded
779 * by redzones, so we simply round up size to simplify logic.
780 */
781 kasan_poison_shadow(addr, round_up(size, KASAN_SHADOW_SCALE_SIZE),
782 KASAN_USE_AFTER_SCOPE);
783}
784EXPORT_SYMBOL(__asan_poison_stack_memory);
785
786/* Emitted by compiler to unpoison large objects when they go into scope. */
787void __asan_unpoison_stack_memory(const void *addr, size_t size)
788{
789 kasan_unpoison_shadow(addr, size);
790}
791EXPORT_SYMBOL(__asan_unpoison_stack_memory);
792
793#ifdef CONFIG_MEMORY_HOTPLUG
794static int kasan_mem_notifier(struct notifier_block *nb,
795 unsigned long action, void *data)
796{
797 return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
798}
799
800static int __init kasan_memhotplug_init(void)
801{
802 pr_info("WARNING: KASAN doesn't support memory hot-add\n");
803 pr_info("Memory hot-add will be disabled\n");
804
805 hotplug_memory_notifier(kasan_mem_notifier, 0);
806
807 return 0;
808}
809
810module_init(kasan_memhotplug_init);
811#endif