diff options
Diffstat (limited to 'arch/x86/mm/kmemcheck/shadow.c')
| -rw-r--r-- | arch/x86/mm/kmemcheck/shadow.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/arch/x86/mm/kmemcheck/shadow.c b/arch/x86/mm/kmemcheck/shadow.c new file mode 100644 index 00000000..aec12421 --- /dev/null +++ b/arch/x86/mm/kmemcheck/shadow.c @@ -0,0 +1,173 @@ +#include <linux/kmemcheck.h> +#include <linux/module.h> +#include <linux/mm.h> + +#include <asm/page.h> +#include <asm/pgtable.h> + +#include "pte.h" +#include "shadow.h" + +/* + * Return the shadow address for the given address. Returns NULL if the + * address is not tracked. + * + * We need to be extremely careful not to follow any invalid pointers, + * because this function can be called for *any* possible address. + */ +void *kmemcheck_shadow_lookup(unsigned long address) +{ + pte_t *pte; + struct page *page; + + if (!virt_addr_valid(address)) + return NULL; + + pte = kmemcheck_pte_lookup(address); + if (!pte) + return NULL; + + page = virt_to_page(address); + if (!page->shadow) + return NULL; + return page->shadow + (address & (PAGE_SIZE - 1)); +} + +static void mark_shadow(void *address, unsigned int n, + enum kmemcheck_shadow status) +{ + unsigned long addr = (unsigned long) address; + unsigned long last_addr = addr + n - 1; + unsigned long page = addr & PAGE_MASK; + unsigned long last_page = last_addr & PAGE_MASK; + unsigned int first_n; + void *shadow; + + /* If the memory range crosses a page boundary, stop there. */ + if (page == last_page) + first_n = n; + else + first_n = page + PAGE_SIZE - addr; + + shadow = kmemcheck_shadow_lookup(addr); + if (shadow) + memset(shadow, status, first_n); + + addr += first_n; + n -= first_n; + + /* Do full-page memset()s. */ + while (n >= PAGE_SIZE) { + shadow = kmemcheck_shadow_lookup(addr); + if (shadow) + memset(shadow, status, PAGE_SIZE); + + addr += PAGE_SIZE; + n -= PAGE_SIZE; + } + + /* Do the remaining page, if any. */ + if (n > 0) { + shadow = kmemcheck_shadow_lookup(addr); + if (shadow) + memset(shadow, status, n); + } +} + +void kmemcheck_mark_unallocated(void *address, unsigned int n) +{ + mark_shadow(address, n, KMEMCHECK_SHADOW_UNALLOCATED); +} + +void kmemcheck_mark_uninitialized(void *address, unsigned int n) +{ + mark_shadow(address, n, KMEMCHECK_SHADOW_UNINITIALIZED); +} + +/* + * Fill the shadow memory of the given address such that the memory at that + * address is marked as being initialized. + */ +void kmemcheck_mark_initialized(void *address, unsigned int n) +{ + mark_shadow(address, n, KMEMCHECK_SHADOW_INITIALIZED); +} +EXPORT_SYMBOL_GPL(kmemcheck_mark_initialized); + +void kmemcheck_mark_freed(void *address, unsigned int n) +{ + mark_shadow(address, n, KMEMCHECK_SHADOW_FREED); +} + +void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n) +{ + unsigned int i; + + for (i = 0; i < n; ++i) + kmemcheck_mark_unallocated(page_address(&p[i]), PAGE_SIZE); +} + +void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n) +{ + unsigned int i; + + for (i = 0; i < n; ++i) + kmemcheck_mark_uninitialized(page_address(&p[i]), PAGE_SIZE); +} + +void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n) +{ + unsigned int i; + + for (i = 0; i < n; ++i) + kmemcheck_mark_initialized(page_address(&p[i]), PAGE_SIZE); +} + +enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size) +{ +#ifdef CONFIG_KMEMCHECK_PARTIAL_OK + uint8_t *x; + unsigned int i; + + x = shadow; + + /* + * Make sure _some_ bytes are initialized. Gcc frequently generates + * code to access neighboring bytes. + */ + for (i = 0; i < size; ++i) { + if (x[i] == KMEMCHECK_SHADOW_INITIALIZED) + return x[i]; + } + + return x[0]; +#else + return kmemcheck_shadow_test_all(shadow, size); +#endif +} + +enum kmemcheck_shadow kmemcheck_shadow_test_all(void *shadow, unsigned int size) +{ + uint8_t *x; + unsigned int i; + + x = shadow; + + /* All bytes must be initialized. */ + for (i = 0; i < size; ++i) { + if (x[i] != KMEMCHECK_SHADOW_INITIALIZED) + return x[i]; + } + + return x[0]; +} + +void kmemcheck_shadow_set(void *shadow, unsigned int size) +{ + uint8_t *x; + unsigned int i; + + x = shadow; + for (i = 0; i < size; ++i) + x[i] = KMEMCHECK_SHADOW_INITIALIZED; +} |