| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2023 Loongson Technology Corporation Limited |
| */ |
| #define pr_fmt(fmt) "kasan: " fmt |
| #include <linux/kasan.h> |
| #include <linux/memblock.h> |
| #include <linux/sched/task.h> |
| |
| #include <asm/tlbflush.h> |
| #include <asm/pgalloc.h> |
| #include <asm-generic/sections.h> |
| |
| static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); |
| |
| #ifdef __PAGETABLE_PUD_FOLDED |
| #define __p4d_none(early, p4d) (0) |
| #else |
| #define __p4d_none(early, p4d) (early ? (p4d_val(p4d) == 0) : \ |
| (__pa(p4d_val(p4d)) == (unsigned long)__pa(kasan_early_shadow_pud))) |
| #endif |
| |
| #ifdef __PAGETABLE_PMD_FOLDED |
| #define __pud_none(early, pud) (0) |
| #else |
| #define __pud_none(early, pud) (early ? (pud_val(pud) == 0) : \ |
| (__pa(pud_val(pud)) == (unsigned long)__pa(kasan_early_shadow_pmd))) |
| #endif |
| |
| #define __pmd_none(early, pmd) (early ? (pmd_val(pmd) == 0) : \ |
| (__pa(pmd_val(pmd)) == (unsigned long)__pa(kasan_early_shadow_pte))) |
| |
| #define __pte_none(early, pte) (early ? pte_none(pte) : \ |
| ((pte_val(pte) & _PFN_MASK) == (unsigned long)__pa(kasan_early_shadow_page))) |
| |
| bool kasan_early_stage = true; |
| |
| void *kasan_mem_to_shadow(const void *addr) |
| { |
| if (!kasan_arch_is_ready()) { |
| return (void *)(kasan_early_shadow_page); |
| } else { |
| unsigned long maddr = (unsigned long)addr; |
| unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff; |
| unsigned long offset = 0; |
| |
| maddr &= XRANGE_SHADOW_MASK; |
| switch (xrange) { |
| case XKPRANGE_CC_SEG: |
| offset = XKPRANGE_CC_SHADOW_OFFSET; |
| break; |
| case XKPRANGE_UC_SEG: |
| offset = XKPRANGE_UC_SHADOW_OFFSET; |
| break; |
| case XKVRANGE_VC_SEG: |
| offset = XKVRANGE_VC_SHADOW_OFFSET; |
| break; |
| default: |
| WARN_ON(1); |
| return NULL; |
| } |
| |
| return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset); |
| } |
| } |
| |
| const void *kasan_shadow_to_mem(const void *shadow_addr) |
| { |
| unsigned long addr = (unsigned long)shadow_addr; |
| |
| if (unlikely(addr > KASAN_SHADOW_END) || |
| unlikely(addr < KASAN_SHADOW_START)) { |
| WARN_ON(1); |
| return NULL; |
| } |
| |
| if (addr >= XKVRANGE_VC_SHADOW_OFFSET) |
| return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START); |
| else if (addr >= XKPRANGE_UC_SHADOW_OFFSET) |
| return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START); |
| else if (addr >= XKPRANGE_CC_SHADOW_OFFSET) |
| return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START); |
| else { |
| WARN_ON(1); |
| return NULL; |
| } |
| } |
| |
| /* |
| * Alloc memory for shadow memory page table. |
| */ |
| 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_ACCESSIBLE, 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(early, READ_ONCE(*pmdp))) { |
| phys_addr_t pte_phys = early ? |
| __pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node); |
| if (!early) |
| memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte)); |
| pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys)); |
| } |
| |
| return 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(early, READ_ONCE(*pudp))) { |
| phys_addr_t pmd_phys = early ? |
| __pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node); |
| if (!early) |
| memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd)); |
| pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys)); |
| } |
| |
| return pmd_offset(pudp, addr); |
| } |
| |
| static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early) |
| { |
| if (__p4d_none(early, READ_ONCE(*p4dp))) { |
| phys_addr_t pud_phys = early ? |
| __pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node); |
| if (!early) |
| memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud)); |
| p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys)); |
| } |
| |
| return 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_zeroed_page(node); |
| next = addr + PAGE_SIZE; |
| set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL)); |
| } while (ptep++, addr = next, addr != end && __pte_none(early, 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(early, 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); |
| } |
| |
| 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); |
| |
| } |
| |
| /* 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); |
| } |
| |
| asmlinkage void __init kasan_early_init(void) |
| { |
| BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE)); |
| BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE)); |
| } |
| |
| static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval) |
| { |
| WRITE_ONCE(*pgdp, pgdval); |
| } |
| |
| 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) |
| kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0)); |
| } |
| |
| void __init kasan_init(void) |
| { |
| u64 i; |
| phys_addr_t pa_start, pa_end; |
| |
| /* |
| * PGD was populated as invalid_pmd_table or invalid_pud_table |
| * in pagetable_init() which depends on how many levels of page |
| * table you are using, but we had to clean the gpd of kasan |
| * shadow memory, as the pgd value is none-zero. |
| * The assertion pgd_none is going to be false and the formal populate |
| * afterwards is not going to create any new pgd at all. |
| */ |
| memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir)); |
| csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH); |
| local_flush_tlb_all(); |
| |
| clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); |
| |
| /* Maps everything to a single page of zeroes */ |
| kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true); |
| |
| kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START), |
| kasan_mem_to_shadow((void *)KFENCE_AREA_END)); |
| |
| kasan_early_stage = false; |
| |
| /* Populate the linear mapping */ |
| 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), NUMA_NO_NODE); |
| } |
| |
| /* Populate modules mapping */ |
| kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR), |
| (unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE); |
| /* |
| * 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(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO)); |
| |
| memset(kasan_early_shadow_page, 0, PAGE_SIZE); |
| csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH); |
| local_flush_tlb_all(); |
| |
| /* At this point kasan is fully initialized. Enable error messages */ |
| init_task.kasan_depth = 0; |
| pr_info("KernelAddressSanitizer initialized.\n"); |
| } |