106 lines
2.5 KiB
C
106 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/kernel.h>
|
|
#include <linux/string.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mmdebug.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/poison.h>
|
|
#include <linux/ratelimit.h>
|
|
#include <linux/kasan.h>
|
|
|
|
bool _page_poisoning_enabled_early;
|
|
EXPORT_SYMBOL(_page_poisoning_enabled_early);
|
|
DEFINE_STATIC_KEY_FALSE(_page_poisoning_enabled);
|
|
EXPORT_SYMBOL(_page_poisoning_enabled);
|
|
|
|
static int __init early_page_poison_param(char *buf)
|
|
{
|
|
return kstrtobool(buf, &_page_poisoning_enabled_early);
|
|
}
|
|
early_param("page_poison", early_page_poison_param);
|
|
|
|
static void poison_page(struct page *page)
|
|
{
|
|
void *addr = kmap_local_page(page);
|
|
|
|
/* KASAN still think the page is in-use, so skip it. */
|
|
kasan_disable_current();
|
|
memset(kasan_reset_tag(addr), PAGE_POISON, PAGE_SIZE);
|
|
kasan_enable_current();
|
|
kunmap_local(addr);
|
|
}
|
|
|
|
void __kernel_poison_pages(struct page *page, int n)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < n; i++)
|
|
poison_page(page + i);
|
|
}
|
|
|
|
static bool single_bit_flip(unsigned char a, unsigned char b)
|
|
{
|
|
unsigned char error = a ^ b;
|
|
|
|
return error && !(error & (error - 1));
|
|
}
|
|
|
|
static void check_poison_mem(struct page *page, unsigned char *mem, size_t bytes)
|
|
{
|
|
static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
|
|
unsigned char *start;
|
|
unsigned char *end;
|
|
|
|
start = memchr_inv(mem, PAGE_POISON, bytes);
|
|
if (!start)
|
|
return;
|
|
|
|
for (end = mem + bytes - 1; end > start; end--) {
|
|
if (*end != PAGE_POISON)
|
|
break;
|
|
}
|
|
|
|
if (!__ratelimit(&ratelimit))
|
|
return;
|
|
else if (start == end && single_bit_flip(*start, PAGE_POISON))
|
|
pr_err("pagealloc: single bit error\n");
|
|
else
|
|
pr_err("pagealloc: memory corruption\n");
|
|
|
|
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start,
|
|
end - start + 1, 1);
|
|
dump_stack();
|
|
dump_page(page, "pagealloc: corrupted page details");
|
|
}
|
|
|
|
static void unpoison_page(struct page *page)
|
|
{
|
|
void *addr;
|
|
|
|
addr = kmap_local_page(page);
|
|
kasan_disable_current();
|
|
/*
|
|
* Page poisoning when enabled poisons each and every page
|
|
* that is freed to buddy. Thus no extra check is done to
|
|
* see if a page was poisoned.
|
|
*/
|
|
check_poison_mem(page, kasan_reset_tag(addr), PAGE_SIZE);
|
|
kasan_enable_current();
|
|
kunmap_local(addr);
|
|
}
|
|
|
|
void __kernel_unpoison_pages(struct page *page, int n)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < n; i++)
|
|
unpoison_page(page + i);
|
|
}
|
|
|
|
#ifndef CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC
|
|
void __kernel_map_pages(struct page *page, int numpages, int enable)
|
|
{
|
|
/* This function does nothing, all work is done via poison pages */
|
|
}
|
|
#endif
|