1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (C) 2019 Andes Technology Corporation 3 4 #include <linux/pfn.h> 5 #include <linux/init_task.h> 6 #include <linux/kasan.h> 7 #include <linux/kernel.h> 8 #include <linux/memblock.h> 9 #include <linux/pgtable.h> 10 #include <asm/tlbflush.h> 11 #include <asm/fixmap.h> 12 #include <asm/pgalloc.h> 13 14 extern pgd_t early_pg_dir[PTRS_PER_PGD]; 15 asmlinkage void __init kasan_early_init(void) 16 { 17 uintptr_t i; 18 pgd_t *pgd = early_pg_dir + pgd_index(KASAN_SHADOW_START); 19 20 for (i = 0; i < PTRS_PER_PTE; ++i) 21 set_pte(kasan_early_shadow_pte + i, 22 mk_pte(virt_to_page(kasan_early_shadow_page), 23 PAGE_KERNEL)); 24 25 for (i = 0; i < PTRS_PER_PMD; ++i) 26 set_pmd(kasan_early_shadow_pmd + i, 27 pfn_pmd(PFN_DOWN 28 (__pa((uintptr_t) kasan_early_shadow_pte)), 29 __pgprot(_PAGE_TABLE))); 30 31 for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END; 32 i += PGDIR_SIZE, ++pgd) 33 set_pgd(pgd, 34 pfn_pgd(PFN_DOWN 35 (__pa(((uintptr_t) kasan_early_shadow_pmd))), 36 __pgprot(_PAGE_TABLE))); 37 38 /* init for swapper_pg_dir */ 39 pgd = pgd_offset_k(KASAN_SHADOW_START); 40 41 for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END; 42 i += PGDIR_SIZE, ++pgd) 43 set_pgd(pgd, 44 pfn_pgd(PFN_DOWN 45 (__pa(((uintptr_t) kasan_early_shadow_pmd))), 46 __pgprot(_PAGE_TABLE))); 47 48 local_flush_tlb_all(); 49 } 50 51 static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end) 52 { 53 phys_addr_t phys_addr; 54 pte_t *ptep, *base_pte; 55 56 if (pmd_none(*pmd)) 57 base_pte = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE); 58 else 59 base_pte = (pte_t *)pmd_page_vaddr(*pmd); 60 61 ptep = base_pte + pte_index(vaddr); 62 63 do { 64 if (pte_none(*ptep)) { 65 phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); 66 set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL)); 67 } 68 } while (ptep++, vaddr += PAGE_SIZE, vaddr != end); 69 70 set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(base_pte)), PAGE_TABLE)); 71 } 72 73 static void __init kasan_populate_pmd(pgd_t *pgd, unsigned long vaddr, unsigned long end) 74 { 75 phys_addr_t phys_addr; 76 pmd_t *pmdp, *base_pmd; 77 unsigned long next; 78 79 base_pmd = (pmd_t *)pgd_page_vaddr(*pgd); 80 if (base_pmd == lm_alias(kasan_early_shadow_pmd)) 81 base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE); 82 83 pmdp = base_pmd + pmd_index(vaddr); 84 85 do { 86 next = pmd_addr_end(vaddr, end); 87 88 if (pmd_none(*pmdp) && IS_ALIGNED(vaddr, PMD_SIZE) && (next - vaddr) >= PMD_SIZE) { 89 phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE); 90 if (phys_addr) { 91 set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL)); 92 continue; 93 } 94 } 95 96 kasan_populate_pte(pmdp, vaddr, next); 97 } while (pmdp++, vaddr = next, vaddr != end); 98 99 /* 100 * Wait for the whole PGD to be populated before setting the PGD in 101 * the page table, otherwise, if we did set the PGD before populating 102 * it entirely, memblock could allocate a page at a physical address 103 * where KASAN is not populated yet and then we'd get a page fault. 104 */ 105 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE)); 106 } 107 108 static void __init kasan_populate_pgd(unsigned long vaddr, unsigned long end) 109 { 110 phys_addr_t phys_addr; 111 pgd_t *pgdp = pgd_offset_k(vaddr); 112 unsigned long next; 113 114 do { 115 next = pgd_addr_end(vaddr, end); 116 117 /* 118 * pgdp can't be none since kasan_early_init initialized all KASAN 119 * shadow region with kasan_early_shadow_pmd: if this is stillthe case, 120 * that means we can try to allocate a hugepage as a replacement. 121 */ 122 if (pgd_page_vaddr(*pgdp) == (unsigned long)lm_alias(kasan_early_shadow_pmd) && 123 IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) { 124 phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE); 125 if (phys_addr) { 126 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL)); 127 continue; 128 } 129 } 130 131 kasan_populate_pmd(pgdp, vaddr, next); 132 } while (pgdp++, vaddr = next, vaddr != end); 133 } 134 135 static void __init kasan_populate(void *start, void *end) 136 { 137 unsigned long vaddr = (unsigned long)start & PAGE_MASK; 138 unsigned long vend = PAGE_ALIGN((unsigned long)end); 139 140 kasan_populate_pgd(vaddr, vend); 141 142 local_flush_tlb_all(); 143 memset(start, KASAN_SHADOW_INIT, end - start); 144 } 145 146 static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end) 147 { 148 unsigned long next; 149 void *p; 150 pgd_t *pgd_k = pgd_offset_k(vaddr); 151 152 do { 153 next = pgd_addr_end(vaddr, end); 154 if (pgd_page_vaddr(*pgd_k) == (unsigned long)lm_alias(kasan_early_shadow_pmd)) { 155 p = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 156 set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE)); 157 } 158 } while (pgd_k++, vaddr = next, vaddr != end); 159 } 160 161 static void __init kasan_shallow_populate(void *start, void *end) 162 { 163 unsigned long vaddr = (unsigned long)start & PAGE_MASK; 164 unsigned long vend = PAGE_ALIGN((unsigned long)end); 165 166 kasan_shallow_populate_pgd(vaddr, vend); 167 local_flush_tlb_all(); 168 } 169 170 void __init kasan_init(void) 171 { 172 phys_addr_t _start, _end; 173 u64 i; 174 175 /* 176 * Populate all kernel virtual address space with kasan_early_shadow_page 177 * except for the linear mapping and the modules/kernel/BPF mapping. 178 */ 179 kasan_populate_early_shadow((void *)KASAN_SHADOW_START, 180 (void *)kasan_mem_to_shadow((void *) 181 VMEMMAP_END)); 182 if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) 183 kasan_shallow_populate( 184 (void *)kasan_mem_to_shadow((void *)VMALLOC_START), 185 (void *)kasan_mem_to_shadow((void *)VMALLOC_END)); 186 else 187 kasan_populate_early_shadow( 188 (void *)kasan_mem_to_shadow((void *)VMALLOC_START), 189 (void *)kasan_mem_to_shadow((void *)VMALLOC_END)); 190 191 /* Populate the linear mapping */ 192 for_each_mem_range(i, &_start, &_end) { 193 void *start = (void *)__va(_start); 194 void *end = (void *)__va(_end); 195 196 if (start >= end) 197 break; 198 199 kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end)); 200 } 201 202 /* Populate kernel, BPF, modules mapping */ 203 kasan_populate(kasan_mem_to_shadow((const void *)MODULES_VADDR), 204 kasan_mem_to_shadow((const void *)BPF_JIT_REGION_END)); 205 206 for (i = 0; i < PTRS_PER_PTE; i++) 207 set_pte(&kasan_early_shadow_pte[i], 208 mk_pte(virt_to_page(kasan_early_shadow_page), 209 __pgprot(_PAGE_PRESENT | _PAGE_READ | 210 _PAGE_ACCESSED))); 211 212 memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE); 213 init_task.kasan_depth = 0; 214 } 215