diff options
Diffstat (limited to 'arch/riscv/mm/kasan_init.c')
| -rw-r--r-- | arch/riscv/mm/kasan_init.c | 474 |
1 files changed, 474 insertions, 0 deletions
diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c new file mode 100644 index 000000000..e12267094 --- /dev/null +++ b/arch/riscv/mm/kasan_init.c @@ -0,0 +1,474 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2019 Andes Technology Corporation + +#include <linux/pfn.h> +#include <linux/init_task.h> +#include <linux/kasan.h> +#include <linux/kernel.h> +#include <linux/memblock.h> +#include <linux/pgtable.h> +#include <asm/tlbflush.h> +#include <asm/fixmap.h> +#include <asm/pgalloc.h> + +/* + * Kasan shadow region must lie at a fixed address across sv39, sv48 and sv57 + * which is right before the kernel. + * + * For sv39, the region is aligned on PGDIR_SIZE so we only need to populate + * the page global directory with kasan_early_shadow_pmd. + * + * For sv48 and sv57, the region is not aligned on PGDIR_SIZE so the mapping + * must be divided as follows: + * - the first PGD entry, although incomplete, is populated with + * kasan_early_shadow_pud/p4d + * - the PGD entries in the middle are populated with kasan_early_shadow_pud/p4d + * - the last PGD entry is shared with the kernel mapping so populated at the + * lower levels pud/p4d + * + * In addition, when shallow populating a kasan region (for example vmalloc), + * this region may also not be aligned on PGDIR size, so we must go down to the + * pud level too. + */ + +extern pgd_t early_pg_dir[PTRS_PER_PGD]; + +static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end) +{ + phys_addr_t phys_addr; + pte_t *ptep, *base_pte; + + if (pmd_none(*pmd)) + base_pte = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE); + else + base_pte = (pte_t *)pmd_page_vaddr(*pmd); + + ptep = base_pte + pte_index(vaddr); + + do { + if (pte_none(*ptep)) { + phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); + set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL)); + } + } while (ptep++, vaddr += PAGE_SIZE, vaddr != end); + + set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(base_pte)), PAGE_TABLE)); +} + +static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned long end) +{ + phys_addr_t phys_addr; + pmd_t *pmdp, *base_pmd; + unsigned long next; + + if (pud_none(*pud)) { + base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE); + } else { + base_pmd = (pmd_t *)pud_pgtable(*pud); + if (base_pmd == lm_alias(kasan_early_shadow_pmd)) + base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE); + } + + pmdp = base_pmd + pmd_index(vaddr); + + do { + next = pmd_addr_end(vaddr, end); + + if (pmd_none(*pmdp) && IS_ALIGNED(vaddr, PMD_SIZE) && (next - vaddr) >= PMD_SIZE) { + phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE); + if (phys_addr) { + set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL)); + continue; + } + } + + kasan_populate_pte(pmdp, vaddr, next); + } while (pmdp++, vaddr = next, vaddr != end); + + /* + * Wait for the whole PGD to be populated before setting the PGD in + * the page table, otherwise, if we did set the PGD before populating + * it entirely, memblock could allocate a page at a physical address + * where KASAN is not populated yet and then we'd get a page fault. + */ + set_pud(pud, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE)); +} + +static void __init kasan_populate_pud(pgd_t *pgd, + unsigned long vaddr, unsigned long end, + bool early) +{ + phys_addr_t phys_addr; + pud_t *pudp, *base_pud; + unsigned long next; + + if (early) { + /* + * We can't use pgd_page_vaddr here as it would return a linear + * mapping address but it is not mapped yet, but when populating + * early_pg_dir, we need the physical address and when populating + * swapper_pg_dir, we need the kernel virtual address so use + * pt_ops facility. + */ + base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd))); + } else if (pgd_none(*pgd)) { + base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE); + memcpy(base_pud, (void *)kasan_early_shadow_pud, + sizeof(pud_t) * PTRS_PER_PUD); + } else { + base_pud = (pud_t *)pgd_page_vaddr(*pgd); + if (base_pud == lm_alias(kasan_early_shadow_pud)) { + base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE); + memcpy(base_pud, (void *)kasan_early_shadow_pud, + sizeof(pud_t) * PTRS_PER_PUD); + } + } + + pudp = base_pud + pud_index(vaddr); + + do { + next = pud_addr_end(vaddr, end); + + if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) { + if (early) { + phys_addr = __pa(((uintptr_t)kasan_early_shadow_pmd)); + set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE)); + continue; + } else { + phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE); + if (phys_addr) { + set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL)); + continue; + } + } + } + + kasan_populate_pmd(pudp, vaddr, next); + } while (pudp++, vaddr = next, vaddr != end); + + /* + * Wait for the whole PGD to be populated before setting the PGD in + * the page table, otherwise, if we did set the PGD before populating + * it entirely, memblock could allocate a page at a physical address + * where KASAN is not populated yet and then we'd get a page fault. + */ + if (!early) + set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE)); +} + +static void __init kasan_populate_p4d(pgd_t *pgd, + unsigned long vaddr, unsigned long end, + bool early) +{ + phys_addr_t phys_addr; + p4d_t *p4dp, *base_p4d; + unsigned long next; + + if (early) { + /* + * We can't use pgd_page_vaddr here as it would return a linear + * mapping address but it is not mapped yet, but when populating + * early_pg_dir, we need the physical address and when populating + * swapper_pg_dir, we need the kernel virtual address so use + * pt_ops facility. + */ + base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd))); + } else { + base_p4d = (p4d_t *)pgd_page_vaddr(*pgd); + if (base_p4d == lm_alias(kasan_early_shadow_p4d)) { + base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE); + memcpy(base_p4d, (void *)kasan_early_shadow_p4d, + sizeof(p4d_t) * PTRS_PER_P4D); + } + } + + p4dp = base_p4d + p4d_index(vaddr); + + do { + next = p4d_addr_end(vaddr, end); + + if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) { + if (early) { + phys_addr = __pa(((uintptr_t)kasan_early_shadow_pud)); + set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE)); + continue; + } else { + phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE); + if (phys_addr) { + set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL)); + continue; + } + } + } + + kasan_populate_pud((pgd_t *)p4dp, vaddr, next, early); + } while (p4dp++, vaddr = next, vaddr != end); + + /* + * Wait for the whole P4D to be populated before setting the P4D in + * the page table, otherwise, if we did set the P4D before populating + * it entirely, memblock could allocate a page at a physical address + * where KASAN is not populated yet and then we'd get a page fault. + */ + if (!early) + set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_p4d)), PAGE_TABLE)); +} + +#define kasan_early_shadow_pgd_next (pgtable_l5_enabled ? \ + (uintptr_t)kasan_early_shadow_p4d : \ + (pgtable_l4_enabled ? \ + (uintptr_t)kasan_early_shadow_pud : \ + (uintptr_t)kasan_early_shadow_pmd)) +#define kasan_populate_pgd_next(pgdp, vaddr, next, early) \ + (pgtable_l5_enabled ? \ + kasan_populate_p4d(pgdp, vaddr, next, early) : \ + (pgtable_l4_enabled ? \ + kasan_populate_pud(pgdp, vaddr, next, early) : \ + kasan_populate_pmd((pud_t *)pgdp, vaddr, next))) + +static void __init kasan_populate_pgd(pgd_t *pgdp, + unsigned long vaddr, unsigned long end, + bool early) +{ + phys_addr_t phys_addr; + unsigned long next; + + do { + next = pgd_addr_end(vaddr, end); + + if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) { + if (early) { + phys_addr = __pa((uintptr_t)kasan_early_shadow_pgd_next); + set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE)); + continue; + } else if (pgd_page_vaddr(*pgdp) == + (unsigned long)lm_alias(kasan_early_shadow_pgd_next)) { + /* + * pgdp can't be none since kasan_early_init + * initialized all KASAN shadow region with + * kasan_early_shadow_pud: if this is still the + * case, that means we can try to allocate a + * hugepage as a replacement. + */ + phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE); + if (phys_addr) { + set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL)); + continue; + } + } + } + + kasan_populate_pgd_next(pgdp, vaddr, next, early); + } while (pgdp++, vaddr = next, vaddr != end); +} + +asmlinkage void __init kasan_early_init(void) +{ + uintptr_t i; + + BUILD_BUG_ON(KASAN_SHADOW_OFFSET != + KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT))); + + for (i = 0; i < PTRS_PER_PTE; ++i) + set_pte(kasan_early_shadow_pte + i, + pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL)); + + for (i = 0; i < PTRS_PER_PMD; ++i) + set_pmd(kasan_early_shadow_pmd + i, + pfn_pmd(PFN_DOWN + (__pa((uintptr_t)kasan_early_shadow_pte)), + PAGE_TABLE)); + + if (pgtable_l4_enabled) { + for (i = 0; i < PTRS_PER_PUD; ++i) + set_pud(kasan_early_shadow_pud + i, + pfn_pud(PFN_DOWN + (__pa(((uintptr_t)kasan_early_shadow_pmd))), + PAGE_TABLE)); + } + + if (pgtable_l5_enabled) { + for (i = 0; i < PTRS_PER_P4D; ++i) + set_p4d(kasan_early_shadow_p4d + i, + pfn_p4d(PFN_DOWN + (__pa(((uintptr_t)kasan_early_shadow_pud))), + PAGE_TABLE)); + } + + kasan_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START), + KASAN_SHADOW_START, KASAN_SHADOW_END, true); + + local_flush_tlb_all(); +} + +void __init kasan_swapper_init(void) +{ + kasan_populate_pgd(pgd_offset_k(KASAN_SHADOW_START), + KASAN_SHADOW_START, KASAN_SHADOW_END, true); + + local_flush_tlb_all(); +} + +static void __init kasan_populate(void *start, void *end) +{ + unsigned long vaddr = (unsigned long)start & PAGE_MASK; + unsigned long vend = PAGE_ALIGN((unsigned long)end); + + kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend, false); + + local_flush_tlb_all(); + memset(start, KASAN_SHADOW_INIT, end - start); +} + +static void __init kasan_shallow_populate_pmd(pgd_t *pgdp, + unsigned long vaddr, unsigned long end) +{ + unsigned long next; + pmd_t *pmdp, *base_pmd; + bool is_kasan_pte; + + base_pmd = (pmd_t *)pgd_page_vaddr(*pgdp); + pmdp = base_pmd + pmd_index(vaddr); + + do { + next = pmd_addr_end(vaddr, end); + is_kasan_pte = (pmd_pgtable(*pmdp) == lm_alias(kasan_early_shadow_pte)); + + if (is_kasan_pte) + pmd_clear(pmdp); + } while (pmdp++, vaddr = next, vaddr != end); +} + +static void __init kasan_shallow_populate_pud(pgd_t *pgdp, + unsigned long vaddr, unsigned long end) +{ + unsigned long next; + pud_t *pudp, *base_pud; + pmd_t *base_pmd; + bool is_kasan_pmd; + + base_pud = (pud_t *)pgd_page_vaddr(*pgdp); + pudp = base_pud + pud_index(vaddr); + + do { + next = pud_addr_end(vaddr, end); + is_kasan_pmd = (pud_pgtable(*pudp) == lm_alias(kasan_early_shadow_pmd)); + + if (!is_kasan_pmd) + continue; + + base_pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE); + set_pud(pudp, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE)); + + if (IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) + continue; + + memcpy(base_pmd, (void *)kasan_early_shadow_pmd, PAGE_SIZE); + kasan_shallow_populate_pmd((pgd_t *)pudp, vaddr, next); + } while (pudp++, vaddr = next, vaddr != end); +} + +static void __init kasan_shallow_populate_p4d(pgd_t *pgdp, + unsigned long vaddr, unsigned long end) +{ + unsigned long next; + p4d_t *p4dp, *base_p4d; + pud_t *base_pud; + bool is_kasan_pud; + + base_p4d = (p4d_t *)pgd_page_vaddr(*pgdp); + p4dp = base_p4d + p4d_index(vaddr); + + do { + next = p4d_addr_end(vaddr, end); + is_kasan_pud = (p4d_pgtable(*p4dp) == lm_alias(kasan_early_shadow_pud)); + + if (!is_kasan_pud) + continue; + + base_pud = memblock_alloc(PAGE_SIZE, PAGE_SIZE); + set_p4d(p4dp, pfn_p4d(PFN_DOWN(__pa(base_pud)), PAGE_TABLE)); + + if (IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) + continue; + + memcpy(base_pud, (void *)kasan_early_shadow_pud, PAGE_SIZE); + kasan_shallow_populate_pud((pgd_t *)p4dp, vaddr, next); + } while (p4dp++, vaddr = next, vaddr != end); +} + +#define kasan_shallow_populate_pgd_next(pgdp, vaddr, next) \ + (pgtable_l5_enabled ? \ + kasan_shallow_populate_p4d(pgdp, vaddr, next) : \ + (pgtable_l4_enabled ? \ + kasan_shallow_populate_pud(pgdp, vaddr, next) : \ + kasan_shallow_populate_pmd(pgdp, vaddr, next))) + +static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end) +{ + unsigned long next; + void *p; + pgd_t *pgd_k = pgd_offset_k(vaddr); + bool is_kasan_pgd_next; + + do { + next = pgd_addr_end(vaddr, end); + is_kasan_pgd_next = (pgd_page_vaddr(*pgd_k) == + (unsigned long)lm_alias(kasan_early_shadow_pgd_next)); + + if (is_kasan_pgd_next) { + p = memblock_alloc(PAGE_SIZE, PAGE_SIZE); + set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE)); + } + + if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) + continue; + + memcpy(p, (void *)kasan_early_shadow_pgd_next, PAGE_SIZE); + kasan_shallow_populate_pgd_next(pgd_k, vaddr, next); + } while (pgd_k++, vaddr = next, vaddr != end); +} + +static void __init kasan_shallow_populate(void *start, void *end) +{ + unsigned long vaddr = (unsigned long)start & PAGE_MASK; + unsigned long vend = PAGE_ALIGN((unsigned long)end); + + kasan_shallow_populate_pgd(vaddr, vend); + local_flush_tlb_all(); +} + +void __init kasan_init(void) +{ + phys_addr_t p_start, p_end; + u64 i; + + if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) + kasan_shallow_populate( + (void *)kasan_mem_to_shadow((void *)VMALLOC_START), + (void *)kasan_mem_to_shadow((void *)VMALLOC_END)); + + /* Populate the linear mapping */ + for_each_mem_range(i, &p_start, &p_end) { + void *start = (void *)__va(p_start); + void *end = (void *)__va(p_end); + + if (start >= end) + break; + + kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end)); + } + + /* Populate kernel, BPF, modules mapping */ + kasan_populate(kasan_mem_to_shadow((const void *)MODULES_VADDR), + kasan_mem_to_shadow((const void *)MODULES_VADDR + SZ_2G)); + + for (i = 0; i < PTRS_PER_PTE; i++) + set_pte(&kasan_early_shadow_pte[i], + mk_pte(virt_to_page(kasan_early_shadow_page), + __pgprot(_PAGE_PRESENT | _PAGE_READ | + _PAGE_ACCESSED))); + + memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE); + init_task.kasan_depth = 0; +} |