diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/kasan/kasan_init.c | 316 |
1 files changed, 303 insertions, 13 deletions
diff --git a/mm/kasan/kasan_init.c b/mm/kasan/kasan_init.c index f436246ccc79..7a2a2f13f86f 100644 --- a/mm/kasan/kasan_init.c +++ b/mm/kasan/kasan_init.c @@ -17,10 +17,13 @@ #include <linux/memblock.h> #include <linux/mm.h> #include <linux/pfn.h> +#include <linux/slab.h> #include <asm/page.h> #include <asm/pgalloc.h> +#include "kasan.h" + /* * This page serves two purposes: * - It used as early shadow memory. The entire shadow region populated @@ -32,22 +35,59 @@ unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss; #if CONFIG_PGTABLE_LEVELS > 4 p4d_t kasan_zero_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss; +static inline bool kasan_p4d_table(pgd_t pgd) +{ + return pgd_page(pgd) == virt_to_page(lm_alias(kasan_zero_p4d)); +} +#else +static inline bool kasan_p4d_table(pgd_t pgd) +{ + return 0; +} #endif #if CONFIG_PGTABLE_LEVELS > 3 pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss; +static inline bool kasan_pud_table(p4d_t p4d) +{ + return p4d_page(p4d) == virt_to_page(lm_alias(kasan_zero_pud)); +} +#else +static inline bool kasan_pud_table(p4d_t p4d) +{ + return 0; +} #endif #if CONFIG_PGTABLE_LEVELS > 2 pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss; +static inline bool kasan_pmd_table(pud_t pud) +{ + return pud_page(pud) == virt_to_page(lm_alias(kasan_zero_pmd)); +} +#else +static inline bool kasan_pmd_table(pud_t pud) +{ + return 0; +} #endif pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss; +static inline bool kasan_pte_table(pmd_t pmd) +{ + return pmd_page(pmd) == virt_to_page(lm_alias(kasan_zero_pte)); +} + +static inline bool kasan_zero_page_entry(pte_t pte) +{ + return pte_page(pte) == virt_to_page(lm_alias(kasan_zero_page)); +} + static __init void *early_alloc(size_t size, int node) { return memblock_virt_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS), BOOTMEM_ALLOC_ACCESSIBLE, node); } -static void __init zero_pte_populate(pmd_t *pmd, unsigned long addr, +static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr, unsigned long end) { pte_t *pte = pte_offset_kernel(pmd, addr); @@ -63,7 +103,7 @@ static void __init zero_pte_populate(pmd_t *pmd, unsigned long addr, } } -static void __init zero_pmd_populate(pud_t *pud, unsigned long addr, +static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr, unsigned long end) { pmd_t *pmd = pmd_offset(pud, addr); @@ -78,14 +118,24 @@ static void __init zero_pmd_populate(pud_t *pud, unsigned long addr, } if (pmd_none(*pmd)) { - pmd_populate_kernel(&init_mm, pmd, - early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + pte_t *p; + + if (slab_is_available()) + p = pte_alloc_one_kernel(&init_mm, addr); + else + p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); + if (!p) + return -ENOMEM; + + pmd_populate_kernel(&init_mm, pmd, p); } zero_pte_populate(pmd, addr, next); } while (pmd++, addr = next, addr != end); + + return 0; } -static void __init zero_pud_populate(p4d_t *p4d, unsigned long addr, +static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr, unsigned long end) { pud_t *pud = pud_offset(p4d, addr); @@ -103,14 +153,24 @@ static void __init zero_pud_populate(p4d_t *p4d, unsigned long addr, } if (pud_none(*pud)) { - pud_populate(&init_mm, pud, - early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + pmd_t *p; + + if (slab_is_available()) { + p = pmd_alloc(&init_mm, pud, addr); + if (!p) + return -ENOMEM; + } else { + pud_populate(&init_mm, pud, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } } zero_pmd_populate(pud, addr, next); } while (pud++, addr = next, addr != end); + + return 0; } -static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr, +static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr, unsigned long end) { p4d_t *p4d = p4d_offset(pgd, addr); @@ -132,11 +192,21 @@ static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr, } if (p4d_none(*p4d)) { - p4d_populate(&init_mm, p4d, - early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + pud_t *p; + + if (slab_is_available()) { + p = pud_alloc(&init_mm, p4d, addr); + if (!p) + return -ENOMEM; + } else { + p4d_populate(&init_mm, p4d, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } } zero_pud_populate(p4d, addr, next); } while (p4d++, addr = next, addr != end); + + return 0; } /** @@ -145,7 +215,7 @@ static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr, * @shadow_start - start of the memory range to populate * @shadow_end - end of the memory range to populate */ -void __init kasan_populate_zero_shadow(const void *shadow_start, +int __ref kasan_populate_zero_shadow(const void *shadow_start, const void *shadow_end) { unsigned long addr = (unsigned long)shadow_start; @@ -191,9 +261,229 @@ void __init kasan_populate_zero_shadow(const void *shadow_start, } if (pgd_none(*pgd)) { - pgd_populate(&init_mm, pgd, - early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + p4d_t *p; + + if (slab_is_available()) { + p = p4d_alloc(&init_mm, pgd, addr); + if (!p) + return -ENOMEM; + } else { + pgd_populate(&init_mm, pgd, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } } zero_p4d_populate(pgd, addr, next); } while (pgd++, addr = next, addr != end); + + return 0; +} + +static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd) +{ + pte_t *pte; + int i; + + for (i = 0; i < PTRS_PER_PTE; i++) { + pte = pte_start + i; + if (!pte_none(*pte)) + return; + } + + pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd))); + pmd_clear(pmd); +} + +static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud) +{ + pmd_t *pmd; + int i; + + for (i = 0; i < PTRS_PER_PMD; i++) { + pmd = pmd_start + i; + if (!pmd_none(*pmd)) + return; + } + + pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud))); + pud_clear(pud); +} + +static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d) +{ + pud_t *pud; + int i; + + for (i = 0; i < PTRS_PER_PUD; i++) { + pud = pud_start + i; + if (!pud_none(*pud)) + return; + } + + pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d))); + p4d_clear(p4d); +} + +static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd) +{ + p4d_t *p4d; + int i; + + for (i = 0; i < PTRS_PER_P4D; i++) { + p4d = p4d_start + i; + if (!p4d_none(*p4d)) + return; + } + + p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd))); + pgd_clear(pgd); +} + +static void kasan_remove_pte_table(pte_t *pte, unsigned long addr, + unsigned long end) +{ + unsigned long next; + + for (; addr < end; addr = next, pte++) { + next = (addr + PAGE_SIZE) & PAGE_MASK; + if (next > end) + next = end; + + if (!pte_present(*pte)) + continue; + + if (WARN_ON(!kasan_zero_page_entry(*pte))) + continue; + pte_clear(&init_mm, addr, pte); + } +} + +static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr, + unsigned long end) +{ + unsigned long next; + + for (; addr < end; addr = next, pmd++) { + pte_t *pte; + + next = pmd_addr_end(addr, end); + + if (!pmd_present(*pmd)) + continue; + + if (kasan_pte_table(*pmd)) { + if (IS_ALIGNED(addr, PMD_SIZE) && + IS_ALIGNED(next, PMD_SIZE)) + pmd_clear(pmd); + continue; + } + pte = pte_offset_kernel(pmd, addr); + kasan_remove_pte_table(pte, addr, next); + kasan_free_pte(pte_offset_kernel(pmd, 0), pmd); + } +} + +static void kasan_remove_pud_table(pud_t *pud, unsigned long addr, + unsigned long end) +{ + unsigned long next; + + for (; addr < end; addr = next, pud++) { + pmd_t *pmd, *pmd_base; + + next = pud_addr_end(addr, end); + + if (!pud_present(*pud)) + continue; + + if (kasan_pmd_table(*pud)) { + if (IS_ALIGNED(addr, PUD_SIZE) && + IS_ALIGNED(next, PUD_SIZE)) + pud_clear(pud); + continue; + } + pmd = pmd_offset(pud, addr); + pmd_base = pmd_offset(pud, 0); + kasan_remove_pmd_table(pmd, addr, next); + kasan_free_pmd(pmd_base, pud); + } +} + +static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr, + unsigned long end) +{ + unsigned long next; + + for (; addr < end; addr = next, p4d++) { + pud_t *pud; + + next = p4d_addr_end(addr, end); + + if (!p4d_present(*p4d)) + continue; + + if (kasan_pud_table(*p4d)) { + if (IS_ALIGNED(addr, P4D_SIZE) && + IS_ALIGNED(next, P4D_SIZE)) + p4d_clear(p4d); + continue; + } + pud = pud_offset(p4d, addr); + kasan_remove_pud_table(pud, addr, next); + kasan_free_pud(pud_offset(p4d, 0), p4d); + } +} + +void kasan_remove_zero_shadow(void *start, unsigned long size) +{ + unsigned long addr, end, next; + pgd_t *pgd; + + addr = (unsigned long)kasan_mem_to_shadow(start); + end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT); + + if (WARN_ON((unsigned long)start % + (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) || + WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE))) + return; + + for (; addr < end; addr = next) { + p4d_t *p4d; + + next = pgd_addr_end(addr, end); + + pgd = pgd_offset_k(addr); + if (!pgd_present(*pgd)) + continue; + + if (kasan_p4d_table(*pgd)) { + if (IS_ALIGNED(addr, PGDIR_SIZE) && + IS_ALIGNED(next, PGDIR_SIZE)) + pgd_clear(pgd); + continue; + } + + p4d = p4d_offset(pgd, addr); + kasan_remove_p4d_table(p4d, addr, next); + kasan_free_p4d(p4d_offset(pgd, 0), pgd); + } +} + +int kasan_add_zero_shadow(void *start, unsigned long size) +{ + int ret; + void *shadow_start, *shadow_end; + + shadow_start = kasan_mem_to_shadow(start); + shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT); + + if (WARN_ON((unsigned long)start % + (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE)) || + WARN_ON(size % (KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE))) + return -EINVAL; + + ret = kasan_populate_zero_shadow(shadow_start, shadow_end); + if (ret) + kasan_remove_zero_shadow(shadow_start, + size >> KASAN_SHADOW_SCALE_SHIFT); + return ret; } |