linux-hardened/mm/debug-pagealloc.c
Stanislaw Gruszka 54c29c635a mm, x86: Remove debug_pagealloc_enabled
When (no)bootmem finish operation, it pass pages to buddy
allocator. Since debug_pagealloc_enabled is not set, we will do
not protect pages, what is not what we want with
CONFIG_DEBUG_PAGEALLOC=y.

To fix remove debug_pagealloc_enabled. That variable was
introduced by commit 12d6f21e "x86: do not PSE on
CONFIG_DEBUG_PAGEALLOC=y" to get more CPA (change page
attribude) code testing. But currently we have CONFIG_CPA_DEBUG,
which test CPA.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1322582711-14571-1-git-send-email-sgruszka@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-06 09:24:07 +01:00

102 lines
2.1 KiB
C

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/page-debug-flags.h>
#include <linux/poison.h>
#include <linux/ratelimit.h>
static inline void set_page_poison(struct page *page)
{
__set_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static inline void clear_page_poison(struct page *page)
{
__clear_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static inline bool page_poison(struct page *page)
{
return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
static void poison_page(struct page *page)
{
void *addr = kmap_atomic(page);
set_page_poison(page);
memset(addr, PAGE_POISON, PAGE_SIZE);
kunmap_atomic(addr);
}
static void 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(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))
printk(KERN_ERR "pagealloc: single bit error\n");
else
printk(KERN_ERR "pagealloc: memory corruption\n");
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start,
end - start + 1, 1);
dump_stack();
}
static void unpoison_page(struct page *page)
{
void *addr;
if (!page_poison(page))
return;
addr = kmap_atomic(page);
check_poison_mem(addr, PAGE_SIZE);
clear_page_poison(page);
kunmap_atomic(addr);
}
static void unpoison_pages(struct page *page, int n)
{
int i;
for (i = 0; i < n; i++)
unpoison_page(page + i);
}
void kernel_map_pages(struct page *page, int numpages, int enable)
{
if (enable)
unpoison_pages(page, numpages);
else
poison_pages(page, numpages);
}