diff options
Diffstat (limited to 'arch/powerpc/mm/kasan/kasan_init_32.c')
| -rw-r--r-- | arch/powerpc/mm/kasan/kasan_init_32.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c new file mode 100644 index 000000000000..0d62be3cba47 --- /dev/null +++ b/arch/powerpc/mm/kasan/kasan_init_32.c @@ -0,0 +1,183 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define DISABLE_BRANCH_PROFILING + +#include <linux/kasan.h> +#include <linux/printk.h> +#include <linux/memblock.h> +#include <linux/sched/task.h> +#include <linux/vmalloc.h> +#include <asm/pgalloc.h> +#include <asm/code-patching.h> +#include <mm/mmu_decl.h> + +static void kasan_populate_pte(pte_t *ptep, pgprot_t prot) +{ + unsigned long va = (unsigned long)kasan_early_shadow_page; + phys_addr_t pa = __pa(kasan_early_shadow_page); + int i; + + for (i = 0; i < PTRS_PER_PTE; i++, ptep++) + __set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 0); +} + +static int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end) +{ + pmd_t *pmd; + unsigned long k_cur, k_next; + + pmd = pmd_offset(pud_offset(pgd_offset_k(k_start), k_start), k_start); + + for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) { + pte_t *new; + + k_next = pgd_addr_end(k_cur, k_end); + if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte) + continue; + + new = pte_alloc_one_kernel(&init_mm); + + if (!new) + return -ENOMEM; + if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) + kasan_populate_pte(new, PAGE_READONLY); + else + kasan_populate_pte(new, PAGE_KERNEL_RO); + pmd_populate_kernel(&init_mm, pmd, new); + } + return 0; +} + +static void __ref *kasan_get_one_page(void) +{ + if (slab_is_available()) + return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO); + + return memblock_alloc(PAGE_SIZE, PAGE_SIZE); +} + +static int __ref kasan_init_region(void *start, size_t size) +{ + unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start); + unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size); + unsigned long k_cur; + int ret; + void *block = NULL; + + ret = kasan_init_shadow_page_tables(k_start, k_end); + if (ret) + return ret; + + if (!slab_is_available()) + block = memblock_alloc(k_end - k_start, PAGE_SIZE); + + for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE) { + pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(k_cur), k_cur), k_cur); + void *va = block ? block + k_cur - k_start : kasan_get_one_page(); + pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL); + + if (!va) + return -ENOMEM; + + __set_pte_at(&init_mm, k_cur, pte_offset_kernel(pmd, k_cur), pte, 0); + } + flush_tlb_kernel_range(k_start, k_end); + return 0; +} + +static void __init kasan_remap_early_shadow_ro(void) +{ + if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) + kasan_populate_pte(kasan_early_shadow_pte, PAGE_READONLY); + else + kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL_RO); + + flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END); +} + +void __init kasan_mmu_init(void) +{ + int ret; + struct memblock_region *reg; + + if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) { + ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END); + + if (ret) + panic("kasan: kasan_init_shadow_page_tables() failed"); + } + + for_each_memblock(memory, reg) { + phys_addr_t base = reg->base; + phys_addr_t top = min(base + reg->size, total_lowmem); + + if (base >= top) + continue; + + ret = kasan_init_region(__va(base), top - base); + if (ret) + panic("kasan: kasan_init_region() failed"); + } +} + +void __init kasan_init(void) +{ + kasan_remap_early_shadow_ro(); + + clear_page(kasan_early_shadow_page); + + /* At this point kasan is fully initialized. Enable error messages */ + init_task.kasan_depth = 0; + pr_info("KASAN init done\n"); +} + +#ifdef CONFIG_MODULES +void *module_alloc(unsigned long size) +{ + void *base = vmalloc_exec(size); + + if (!base) + return NULL; + + if (!kasan_init_region(base, size)) + return base; + + vfree(base); + + return NULL; +} +#endif + +#ifdef CONFIG_PPC_BOOK3S_32 +u8 __initdata early_hash[256 << 10] __aligned(256 << 10) = {0}; + +static void __init kasan_early_hash_table(void) +{ + modify_instruction_site(&patch__hash_page_A0, 0xffff, __pa(early_hash) >> 16); + modify_instruction_site(&patch__flush_hash_A0, 0xffff, __pa(early_hash) >> 16); + + Hash = (struct hash_pte *)early_hash; +} +#else +static void __init kasan_early_hash_table(void) {} +#endif + +void __init kasan_early_init(void) +{ + unsigned long addr = KASAN_SHADOW_START; + unsigned long end = KASAN_SHADOW_END; + unsigned long next; + pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(addr), addr), addr); + + BUILD_BUG_ON(KASAN_SHADOW_START & ~PGDIR_MASK); + + kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL); + + do { + next = pgd_addr_end(addr, end); + pmd_populate_kernel(&init_mm, pmd, kasan_early_shadow_pte); + } while (pmd++, addr = next, addr != end); + + if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) + kasan_early_hash_table(); +} |