d099e491b8
It's sometimes useful to know the physical address which has beencorrupted, especially in systems with multiple bus masters and DMA engines the capability of writing to memory. It's may also be useful for identifying the location of failures of memory cells in cases of device-specific corruption. So print the physical start address of the page to help in these scenarios. Change-Id: I081edd8b1c06913c0057a6cb9dda18077cfbdc30 Signed-off-by: Matt Wagantall <mattw@codeaurora.org> Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
151 lines
3 KiB
C
151 lines
3 KiB
C
#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/page_ext.h>
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#include <linux/poison.h>
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#include <linux/ratelimit.h>
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#ifndef mark_addr_rdonly
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#define mark_addr_rdonly(a)
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#endif
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#ifndef mark_addr_rdwrite
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#define mark_addr_rdwrite(a)
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#endif
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static bool page_poisoning_enabled __read_mostly;
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static bool need_page_poisoning(void)
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{
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if (!debug_pagealloc_enabled())
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return false;
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return true;
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}
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static void init_page_poisoning(void)
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{
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if (!debug_pagealloc_enabled())
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return;
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page_poisoning_enabled = true;
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}
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struct page_ext_operations page_poisoning_ops = {
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.need = need_page_poisoning,
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.init = init_page_poisoning,
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};
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static inline void set_page_poison(struct page *page)
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{
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struct page_ext *page_ext;
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page_ext = lookup_page_ext(page);
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__set_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
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}
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static inline void clear_page_poison(struct page *page)
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{
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struct page_ext *page_ext;
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page_ext = lookup_page_ext(page);
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__clear_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
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}
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static inline bool page_poison(struct page *page)
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{
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struct page_ext *page_ext;
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page_ext = lookup_page_ext(page);
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return test_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
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}
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static void poison_page(struct page *page)
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{
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void *addr = kmap_atomic(page);
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set_page_poison(page);
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memset(addr, PAGE_POISON, PAGE_SIZE);
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mark_addr_rdonly(addr);
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kunmap_atomic(addr);
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}
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static void poison_pages(struct page *page, int n)
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{
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int i;
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for (i = 0; i < n; i++)
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poison_page(page + i);
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}
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static bool single_bit_flip(unsigned char a, unsigned char b)
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{
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unsigned char error = a ^ b;
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return error && !(error & (error - 1));
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}
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static void check_poison_mem(struct page *page,
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unsigned char *mem, size_t bytes)
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{
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static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
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unsigned char *start;
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unsigned char *end;
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start = memchr_inv(mem, PAGE_POISON, bytes);
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if (!start)
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return;
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for (end = mem + bytes - 1; end > start; end--) {
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if (*end != PAGE_POISON)
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break;
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}
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if (!__ratelimit(&ratelimit))
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return;
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else if (start == end && single_bit_flip(*start, PAGE_POISON))
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pr_err("pagealloc: single bit error on page with phys start 0x%lx\n",
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(unsigned long)page_to_phys(page));
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else
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pr_err("pagealloc: memory corruption on page with phys start 0x%lx\n",
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(unsigned long)page_to_phys(page));
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print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start,
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end - start + 1, 1);
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BUG_ON(PANIC_CORRUPTION);
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dump_stack();
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}
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static void unpoison_page(struct page *page)
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{
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void *addr;
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if (!page_poison(page))
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return;
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addr = kmap_atomic(page);
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check_poison_mem(page, addr, PAGE_SIZE);
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mark_addr_rdwrite(addr);
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clear_page_poison(page);
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kunmap_atomic(addr);
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}
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static void unpoison_pages(struct page *page, int n)
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{
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int i;
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for (i = 0; i < n; i++)
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unpoison_page(page + i);
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}
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void __kernel_map_pages(struct page *page, int numpages, int enable)
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{
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if (!page_poisoning_enabled)
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return;
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if (enable)
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unpoison_pages(page, numpages);
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else
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poison_pages(page, numpages);
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}
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