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// SPDX-License-Identifier: GPL-2.0
/*
* This file contains hardware tag-based KASAN specific error reporting code.
*
* Copyright (c) 2020 Google, Inc.
* Author: Andrey Konovalov <andreyknvl@google.com>
*/
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/memory.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/types.h>
#include "kasan.h"
const void *kasan_find_first_bad_addr(const void *addr, size_t size)
{
/*
* Hardware Tag-Based KASAN only calls this function for normal memory
* accesses, and thus addr points precisely to the first bad address
* with an invalid (and present) memory tag. Therefore:
* 1. Return the address as is without walking memory tags.
* 2. Skip the addr_has_metadata check.
*/
return kasan_reset_tag(addr);
}
size_t kasan_get_alloc_size(void *object, struct kmem_cache *cache)
{
size_t size = 0;
int i = 0;
u8 memory_tag;
/*
* Skip the addr_has_metadata check, as this function only operates on
* slab memory, which must have metadata.
*/
/*
* The loop below returns 0 for freed objects, for which KASAN cannot
* calculate the allocation size based on the metadata.
*/
while (size < cache->object_size) {
memory_tag = hw_get_mem_tag(object + i * KASAN_GRANULE_SIZE);
if (memory_tag != KASAN_TAG_INVALID)
size += KASAN_GRANULE_SIZE;
else
return size;
i++;
}
return cache->object_size;
}
void kasan_metadata_fetch_row(char *buffer, void *row)
{
int i;
for (i = 0; i < META_BYTES_PER_ROW; i++)
buffer[i] = hw_get_mem_tag(row + i * KASAN_GRANULE_SIZE);
}
void kasan_print_tags(u8 addr_tag, const void *addr)
{
u8 memory_tag = hw_get_mem_tag((void *)addr);
pr_err("Pointer tag: [%02x], memory tag: [%02x]\n",
addr_tag, memory_tag);
}
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