// 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; if (maddr >= FIXADDR_START) return (void *)(kasan_early_shadow_page); 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"); }