diff options
Diffstat (limited to 'arch/x86/mm/kasan_init_64.c')
| -rw-r--r-- | arch/x86/mm/kasan_init_64.c | 47 |
1 files changed, 42 insertions, 5 deletions
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index 4860906c6b9f..e1840f3db5b5 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -1,3 +1,4 @@ +#define pr_fmt(fmt) "kasan: " fmt #include <linux/bootmem.h> #include <linux/kasan.h> #include <linux/kdebug.h> @@ -11,7 +12,19 @@ extern pgd_t early_level4_pgt[PTRS_PER_PGD]; extern struct range pfn_mapped[E820_X_MAX]; -extern unsigned char kasan_zero_page[PAGE_SIZE]; +static pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss; +static pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss; +static pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss; + +/* + * This page used as early shadow. We don't use empty_zero_page + * at early stages, stack instrumentation could write some garbage + * to this page. + * Latter we reuse it as zero shadow for large ranges of memory + * that allowed to access, but not instrumented by kasan + * (vmalloc/vmemmap ...). + */ +static unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss; static int __init map_range(struct range *range) { @@ -36,7 +49,7 @@ static void __init clear_pgds(unsigned long start, pgd_clear(pgd_offset_k(start)); } -void __init kasan_map_early_shadow(pgd_t *pgd) +static void __init kasan_map_early_shadow(pgd_t *pgd) { int i; unsigned long start = KASAN_SHADOW_START; @@ -73,7 +86,7 @@ static int __init zero_pmd_populate(pud_t *pud, unsigned long addr, while (IS_ALIGNED(addr, PMD_SIZE) && addr + PMD_SIZE <= end) { WARN_ON(!pmd_none(*pmd)); set_pmd(pmd, __pmd(__pa_nodebug(kasan_zero_pte) - | __PAGE_KERNEL_RO)); + | _KERNPG_TABLE)); addr += PMD_SIZE; pmd = pmd_offset(pud, addr); } @@ -99,7 +112,7 @@ static int __init zero_pud_populate(pgd_t *pgd, unsigned long addr, while (IS_ALIGNED(addr, PUD_SIZE) && addr + PUD_SIZE <= end) { WARN_ON(!pud_none(*pud)); set_pud(pud, __pud(__pa_nodebug(kasan_zero_pmd) - | __PAGE_KERNEL_RO)); + | _KERNPG_TABLE)); addr += PUD_SIZE; pud = pud_offset(pgd, addr); } @@ -124,7 +137,7 @@ static int __init zero_pgd_populate(unsigned long addr, unsigned long end) while (IS_ALIGNED(addr, PGDIR_SIZE) && addr + PGDIR_SIZE <= end) { WARN_ON(!pgd_none(*pgd)); set_pgd(pgd, __pgd(__pa_nodebug(kasan_zero_pud) - | __PAGE_KERNEL_RO)); + | _KERNPG_TABLE)); addr += PGDIR_SIZE; pgd = pgd_offset_k(addr); } @@ -166,6 +179,26 @@ static struct notifier_block kasan_die_notifier = { }; #endif +void __init kasan_early_init(void) +{ + int i; + pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL; + pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE; + pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE; + + for (i = 0; i < PTRS_PER_PTE; i++) + kasan_zero_pte[i] = __pte(pte_val); + + for (i = 0; i < PTRS_PER_PMD; i++) + kasan_zero_pmd[i] = __pmd(pmd_val); + + for (i = 0; i < PTRS_PER_PUD; i++) + kasan_zero_pud[i] = __pud(pud_val); + + kasan_map_early_shadow(early_level4_pgt); + kasan_map_early_shadow(init_level4_pgt); +} + void __init kasan_init(void) { int i; @@ -176,6 +209,7 @@ void __init kasan_init(void) memcpy(early_level4_pgt, init_level4_pgt, sizeof(early_level4_pgt)); load_cr3(early_level4_pgt); + __flush_tlb_all(); clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); @@ -202,5 +236,8 @@ void __init kasan_init(void) memset(kasan_zero_page, 0, PAGE_SIZE); load_cr3(init_level4_pgt); + __flush_tlb_all(); init_task.kasan_depth = 0; + + pr_info("Kernel address sanitizer initialized\n"); } |