b1eeab6768
This adds support for tracking the initializedness of memory that was allocated with the page allocator. Highmem requests are not tracked. Cc: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> [build fix for !CONFIG_KMEMCHECK] Signed-off-by: Ingo Molnar <mingo@elte.hu> [rebased for mainline inclusion] Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
163 lines
3.5 KiB
C
163 lines
3.5 KiB
C
#include <linux/kmemcheck.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include "pte.h"
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#include "shadow.h"
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/*
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* Return the shadow address for the given address. Returns NULL if the
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* address is not tracked.
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*
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* We need to be extremely careful not to follow any invalid pointers,
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* because this function can be called for *any* possible address.
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*/
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void *kmemcheck_shadow_lookup(unsigned long address)
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{
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pte_t *pte;
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struct page *page;
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if (!virt_addr_valid(address))
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return NULL;
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pte = kmemcheck_pte_lookup(address);
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if (!pte)
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return NULL;
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page = virt_to_page(address);
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if (!page->shadow)
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return NULL;
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return page->shadow + (address & (PAGE_SIZE - 1));
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}
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static void mark_shadow(void *address, unsigned int n,
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enum kmemcheck_shadow status)
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{
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unsigned long addr = (unsigned long) address;
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unsigned long last_addr = addr + n - 1;
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unsigned long page = addr & PAGE_MASK;
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unsigned long last_page = last_addr & PAGE_MASK;
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unsigned int first_n;
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void *shadow;
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/* If the memory range crosses a page boundary, stop there. */
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if (page == last_page)
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first_n = n;
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else
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first_n = page + PAGE_SIZE - addr;
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shadow = kmemcheck_shadow_lookup(addr);
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if (shadow)
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memset(shadow, status, first_n);
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addr += first_n;
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n -= first_n;
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/* Do full-page memset()s. */
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while (n >= PAGE_SIZE) {
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shadow = kmemcheck_shadow_lookup(addr);
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if (shadow)
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memset(shadow, status, PAGE_SIZE);
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addr += PAGE_SIZE;
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n -= PAGE_SIZE;
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}
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/* Do the remaining page, if any. */
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if (n > 0) {
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shadow = kmemcheck_shadow_lookup(addr);
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if (shadow)
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memset(shadow, status, n);
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}
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}
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void kmemcheck_mark_unallocated(void *address, unsigned int n)
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{
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mark_shadow(address, n, KMEMCHECK_SHADOW_UNALLOCATED);
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}
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void kmemcheck_mark_uninitialized(void *address, unsigned int n)
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{
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mark_shadow(address, n, KMEMCHECK_SHADOW_UNINITIALIZED);
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}
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/*
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* Fill the shadow memory of the given address such that the memory at that
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* address is marked as being initialized.
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*/
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void kmemcheck_mark_initialized(void *address, unsigned int n)
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{
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mark_shadow(address, n, KMEMCHECK_SHADOW_INITIALIZED);
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}
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EXPORT_SYMBOL_GPL(kmemcheck_mark_initialized);
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void kmemcheck_mark_freed(void *address, unsigned int n)
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{
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mark_shadow(address, n, KMEMCHECK_SHADOW_FREED);
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}
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void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n)
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{
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unsigned int i;
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for (i = 0; i < n; ++i)
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kmemcheck_mark_unallocated(page_address(&p[i]), PAGE_SIZE);
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}
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void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n)
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{
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unsigned int i;
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for (i = 0; i < n; ++i)
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kmemcheck_mark_uninitialized(page_address(&p[i]), PAGE_SIZE);
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}
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void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n)
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{
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unsigned int i;
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for (i = 0; i < n; ++i)
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kmemcheck_mark_initialized(page_address(&p[i]), PAGE_SIZE);
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}
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enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size)
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{
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uint8_t *x;
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unsigned int i;
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x = shadow;
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#ifdef CONFIG_KMEMCHECK_PARTIAL_OK
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/*
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* Make sure _some_ bytes are initialized. Gcc frequently generates
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* code to access neighboring bytes.
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*/
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for (i = 0; i < size; ++i) {
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if (x[i] == KMEMCHECK_SHADOW_INITIALIZED)
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return x[i];
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}
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#else
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/* All bytes must be initialized. */
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for (i = 0; i < size; ++i) {
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if (x[i] != KMEMCHECK_SHADOW_INITIALIZED)
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return x[i];
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}
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#endif
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return x[0];
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}
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void kmemcheck_shadow_set(void *shadow, unsigned int size)
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{
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uint8_t *x;
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unsigned int i;
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x = shadow;
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for (i = 0; i < size; ++i)
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x[i] = KMEMCHECK_SHADOW_INITIALIZED;
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}
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