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Diffstat (limited to 'arch/arm64/mm/kasan_init.c')
| -rw-r--r-- | arch/arm64/mm/kasan_init.c | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c new file mode 100644 index 000000000..f17d066e8 --- /dev/null +++ b/arch/arm64/mm/kasan_init.c @@ -0,0 +1,308 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * This file contains kasan initialization code for ARM64. + * + * Copyright (c) 2015 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> + */ + +#define pr_fmt(fmt) "kasan: " fmt +#include <linux/kasan.h> +#include <linux/kernel.h> +#include <linux/sched/task.h> +#include <linux/memblock.h> +#include <linux/start_kernel.h> +#include <linux/mm.h> + +#include <asm/mmu_context.h> +#include <asm/kernel-pgtable.h> +#include <asm/page.h> +#include <asm/pgalloc.h> +#include <asm/sections.h> +#include <asm/tlbflush.h> + +#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) + +static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE); + +/* + * The p*d_populate functions call virt_to_phys implicitly so they can't be used + * directly on kernel symbols (bm_p*d). All the early functions are called too + * early to use lm_alias so __p*d_populate functions must be used to populate + * with the physical address from __pa_symbol. + */ + +static phys_addr_t __init kasan_alloc_zeroed_page(int node) +{ + void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE, + __pa(MAX_DMA_ADDRESS), + MEMBLOCK_ALLOC_NOLEAKTRACE, node); + if (!p) + panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n", + __func__, PAGE_SIZE, PAGE_SIZE, node, + __pa(MAX_DMA_ADDRESS)); + + return __pa(p); +} + +static phys_addr_t __init kasan_alloc_raw_page(int node) +{ + void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE, + __pa(MAX_DMA_ADDRESS), + MEMBLOCK_ALLOC_NOLEAKTRACE, + node); + if (!p) + panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n", + __func__, PAGE_SIZE, PAGE_SIZE, node, + __pa(MAX_DMA_ADDRESS)); + + return __pa(p); +} + +static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, + bool early) +{ + if (pmd_none(READ_ONCE(*pmdp))) { + phys_addr_t pte_phys = early ? + __pa_symbol(kasan_early_shadow_pte) + : kasan_alloc_zeroed_page(node); + __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE); + } + + return early ? pte_offset_kimg(pmdp, addr) + : pte_offset_kernel(pmdp, addr); +} + +static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, + bool early) +{ + if (pud_none(READ_ONCE(*pudp))) { + phys_addr_t pmd_phys = early ? + __pa_symbol(kasan_early_shadow_pmd) + : kasan_alloc_zeroed_page(node); + __pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE); + } + + return early ? pmd_offset_kimg(pudp, addr) : pmd_offset(pudp, addr); +} + +static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, + bool early) +{ + if (p4d_none(READ_ONCE(*p4dp))) { + phys_addr_t pud_phys = early ? + __pa_symbol(kasan_early_shadow_pud) + : kasan_alloc_zeroed_page(node); + __p4d_populate(p4dp, pud_phys, P4D_TYPE_TABLE); + } + + return early ? pud_offset_kimg(p4dp, addr) : pud_offset(p4dp, addr); +} + +static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr, + unsigned long end, int node, bool early) +{ + unsigned long next; + pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early); + + do { + phys_addr_t page_phys = early ? + __pa_symbol(kasan_early_shadow_page) + : kasan_alloc_raw_page(node); + if (!early) + memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE); + next = addr + PAGE_SIZE; + set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL)); + } while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep))); +} + +static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr, + unsigned long end, int node, bool early) +{ + unsigned long next; + pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early); + + do { + next = pmd_addr_end(addr, end); + kasan_pte_populate(pmdp, addr, next, node, early); + } while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp))); +} + +static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr, + unsigned long end, int node, bool early) +{ + unsigned long next; + pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early); + + do { + next = pud_addr_end(addr, end); + kasan_pmd_populate(pudp, addr, next, node, early); + } while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp))); +} + +static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr, + unsigned long end, int node, bool early) +{ + unsigned long next; + p4d_t *p4dp = p4d_offset(pgdp, addr); + + do { + next = p4d_addr_end(addr, end); + kasan_pud_populate(p4dp, addr, next, node, early); + } while (p4dp++, addr = next, addr != end); +} + +static void __init kasan_pgd_populate(unsigned long addr, unsigned long end, + int node, bool early) +{ + unsigned long next; + pgd_t *pgdp; + + pgdp = pgd_offset_k(addr); + do { + next = pgd_addr_end(addr, end); + kasan_p4d_populate(pgdp, addr, next, node, early); + } while (pgdp++, addr = next, addr != end); +} + +/* The early shadow maps everything to a single page of zeroes */ +asmlinkage void __init kasan_early_init(void) +{ + BUILD_BUG_ON(KASAN_SHADOW_OFFSET != + KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT))); + BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS), PGDIR_SIZE)); + BUILD_BUG_ON(!IS_ALIGNED(_KASAN_SHADOW_START(VA_BITS_MIN), PGDIR_SIZE)); + BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE)); + kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, + true); +} + +/* Set up full kasan mappings, ensuring that the mapped pages are zeroed */ +static void __init kasan_map_populate(unsigned long start, unsigned long end, + int node) +{ + kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false); +} + +/* + * Copy the current shadow region into a new pgdir. + */ +void __init kasan_copy_shadow(pgd_t *pgdir) +{ + pgd_t *pgdp, *pgdp_new, *pgdp_end; + + pgdp = pgd_offset_k(KASAN_SHADOW_START); + pgdp_end = pgd_offset_k(KASAN_SHADOW_END); + pgdp_new = pgd_offset_pgd(pgdir, KASAN_SHADOW_START); + do { + set_pgd(pgdp_new, READ_ONCE(*pgdp)); + } while (pgdp++, pgdp_new++, pgdp != pgdp_end); +} + +static void __init clear_pgds(unsigned long start, + unsigned long end) +{ + /* + * Remove references to kasan page tables from + * swapper_pg_dir. pgd_clear() can't be used + * here because it's nop on 2,3-level pagetable setups + */ + for (; start < end; start += PGDIR_SIZE) + set_pgd(pgd_offset_k(start), __pgd(0)); +} + +static void __init kasan_init_shadow(void) +{ + u64 kimg_shadow_start, kimg_shadow_end; + u64 mod_shadow_start; + u64 vmalloc_shadow_end; + phys_addr_t pa_start, pa_end; + u64 i; + + kimg_shadow_start = (u64)kasan_mem_to_shadow(KERNEL_START) & PAGE_MASK; + kimg_shadow_end = PAGE_ALIGN((u64)kasan_mem_to_shadow(KERNEL_END)); + + mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR); + + vmalloc_shadow_end = (u64)kasan_mem_to_shadow((void *)VMALLOC_END); + + /* + * We are going to perform proper setup of shadow memory. + * At first we should unmap early shadow (clear_pgds() call below). + * However, instrumented code couldn't execute without shadow memory. + * tmp_pg_dir used to keep early shadow mapped until full shadow + * setup will be finished. + */ + memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir)); + dsb(ishst); + cpu_replace_ttbr1(lm_alias(tmp_pg_dir), idmap_pg_dir); + + clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); + + kasan_map_populate(kimg_shadow_start, kimg_shadow_end, + early_pfn_to_nid(virt_to_pfn(lm_alias(KERNEL_START)))); + + kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END), + (void *)mod_shadow_start); + + BUILD_BUG_ON(VMALLOC_START != MODULES_END); + kasan_populate_early_shadow((void *)vmalloc_shadow_end, + (void *)KASAN_SHADOW_END); + + for_each_mem_range(i, &pa_start, &pa_end) { + void *start = (void *)__phys_to_virt(pa_start); + void *end = (void *)__phys_to_virt(pa_end); + + if (start >= end) + break; + + kasan_map_populate((unsigned long)kasan_mem_to_shadow(start), + (unsigned long)kasan_mem_to_shadow(end), + early_pfn_to_nid(virt_to_pfn(start))); + } + + /* + * KAsan may reuse the contents of kasan_early_shadow_pte directly, + * so we should make sure that it maps the zero page read-only. + */ + for (i = 0; i < PTRS_PER_PTE; i++) + set_pte(&kasan_early_shadow_pte[i], + pfn_pte(sym_to_pfn(kasan_early_shadow_page), + PAGE_KERNEL_RO)); + + memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE); + cpu_replace_ttbr1(lm_alias(swapper_pg_dir), idmap_pg_dir); +} + +static void __init kasan_init_depth(void) +{ + init_task.kasan_depth = 0; +} + +#ifdef CONFIG_KASAN_VMALLOC +void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size) +{ + unsigned long shadow_start, shadow_end; + + if (!is_vmalloc_or_module_addr(start)) + return; + + shadow_start = (unsigned long)kasan_mem_to_shadow(start); + shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE); + shadow_end = (unsigned long)kasan_mem_to_shadow(start + size); + shadow_end = ALIGN(shadow_end, PAGE_SIZE); + kasan_map_populate(shadow_start, shadow_end, NUMA_NO_NODE); +} +#endif + +void __init kasan_init(void) +{ + kasan_init_shadow(); + kasan_init_depth(); +#if defined(CONFIG_KASAN_GENERIC) + /* CONFIG_KASAN_SW_TAGS also requires kasan_init_sw_tags(). */ + pr_info("KernelAddressSanitizer initialized (generic)\n"); +#endif +} + +#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ |