| // 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))); |
| /* |
| * We cannot check the actual value of KASAN_SHADOW_START during build, |
| * as it depends on vabits_actual. As a best-effort approach, check |
| * potential values calculated based on VA_BITS and VA_BITS_MIN. |
| */ |
| 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) |
| /* |
| * Generic KASAN is now fully initialized. |
| * Software and Hardware Tag-Based modes still require |
| * kasan_init_sw_tags() and kasan_init_hw_tags() correspondingly. |
| */ |
| pr_info("KernelAddressSanitizer initialized (generic)\n"); |
| #endif |
| } |
| |
| #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ |