1 // SPDX-License-Identifier: GPL-2.0 2 3 #define DISABLE_BRANCH_PROFILING 4 5 #include <linux/kasan.h> 6 #include <linux/printk.h> 7 #include <linux/memblock.h> 8 #include <linux/sched/task.h> 9 #include <asm/pgalloc.h> 10 #include <asm/code-patching.h> 11 #include <mm/mmu_decl.h> 12 13 static pgprot_t __init kasan_prot_ro(void) 14 { 15 if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) 16 return PAGE_READONLY; 17 18 return PAGE_KERNEL_RO; 19 } 20 21 static void __init kasan_populate_pte(pte_t *ptep, pgprot_t prot) 22 { 23 unsigned long va = (unsigned long)kasan_early_shadow_page; 24 phys_addr_t pa = __pa(kasan_early_shadow_page); 25 int i; 26 27 for (i = 0; i < PTRS_PER_PTE; i++, ptep++) 28 __set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 1); 29 } 30 31 int __init kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end) 32 { 33 pmd_t *pmd; 34 unsigned long k_cur, k_next; 35 36 pmd = pmd_off_k(k_start); 37 38 for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) { 39 pte_t *new; 40 41 k_next = pgd_addr_end(k_cur, k_end); 42 if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte) 43 continue; 44 45 new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE); 46 47 if (!new) 48 return -ENOMEM; 49 kasan_populate_pte(new, PAGE_KERNEL); 50 pmd_populate_kernel(&init_mm, pmd, new); 51 } 52 return 0; 53 } 54 55 int __init __weak kasan_init_region(void *start, size_t size) 56 { 57 unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start); 58 unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size); 59 unsigned long k_cur; 60 int ret; 61 void *block; 62 63 ret = kasan_init_shadow_page_tables(k_start, k_end); 64 if (ret) 65 return ret; 66 67 k_start = k_start & PAGE_MASK; 68 block = memblock_alloc(k_end - k_start, PAGE_SIZE); 69 if (!block) 70 return -ENOMEM; 71 72 for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) { 73 pmd_t *pmd = pmd_off_k(k_cur); 74 void *va = block + k_cur - k_start; 75 pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL); 76 77 __set_pte_at(&init_mm, k_cur, pte_offset_kernel(pmd, k_cur), pte, 0); 78 } 79 flush_tlb_kernel_range(k_start, k_end); 80 return 0; 81 } 82 83 void __init 84 kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte) 85 { 86 unsigned long k_cur; 87 88 for (k_cur = k_start; k_cur != k_end; k_cur += PAGE_SIZE) { 89 pmd_t *pmd = pmd_off_k(k_cur); 90 pte_t *ptep = pte_offset_kernel(pmd, k_cur); 91 92 if (pte_page(*ptep) != virt_to_page(lm_alias(kasan_early_shadow_page))) 93 continue; 94 95 __set_pte_at(&init_mm, k_cur, ptep, pte, 0); 96 } 97 98 flush_tlb_kernel_range(k_start, k_end); 99 } 100 101 static void __init kasan_remap_early_shadow_ro(void) 102 { 103 pgprot_t prot = kasan_prot_ro(); 104 phys_addr_t pa = __pa(kasan_early_shadow_page); 105 106 kasan_populate_pte(kasan_early_shadow_pte, prot); 107 108 kasan_update_early_region(KASAN_SHADOW_START, KASAN_SHADOW_END, 109 pfn_pte(PHYS_PFN(pa), prot)); 110 } 111 112 static void __init kasan_unmap_early_shadow_vmalloc(void) 113 { 114 unsigned long k_start = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START); 115 unsigned long k_end = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_END); 116 117 kasan_update_early_region(k_start, k_end, __pte(0)); 118 119 #ifdef MODULES_VADDR 120 k_start = (unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR); 121 k_end = (unsigned long)kasan_mem_to_shadow((void *)MODULES_END); 122 kasan_update_early_region(k_start, k_end, __pte(0)); 123 #endif 124 } 125 126 void __init kasan_mmu_init(void) 127 { 128 int ret; 129 130 if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) { 131 ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END); 132 133 if (ret) 134 panic("kasan: kasan_init_shadow_page_tables() failed"); 135 } 136 } 137 138 void __init kasan_init(void) 139 { 140 phys_addr_t base, end; 141 u64 i; 142 int ret; 143 144 for_each_mem_range(i, &base, &end) { 145 phys_addr_t top = min(end, total_lowmem); 146 147 if (base >= top) 148 continue; 149 150 ret = kasan_init_region(__va(base), top - base); 151 if (ret) 152 panic("kasan: kasan_init_region() failed"); 153 } 154 155 if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { 156 ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END); 157 158 if (ret) 159 panic("kasan: kasan_init_shadow_page_tables() failed"); 160 } 161 162 kasan_remap_early_shadow_ro(); 163 164 clear_page(kasan_early_shadow_page); 165 166 /* At this point kasan is fully initialized. Enable error messages */ 167 init_task.kasan_depth = 0; 168 pr_info("KASAN init done\n"); 169 } 170 171 void __init kasan_late_init(void) 172 { 173 if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) 174 kasan_unmap_early_shadow_vmalloc(); 175 } 176 177 void __init kasan_early_init(void) 178 { 179 unsigned long addr = KASAN_SHADOW_START; 180 unsigned long end = KASAN_SHADOW_END; 181 unsigned long next; 182 pmd_t *pmd = pmd_off_k(addr); 183 184 BUILD_BUG_ON(KASAN_SHADOW_START & ~PGDIR_MASK); 185 186 kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL); 187 188 do { 189 next = pgd_addr_end(addr, end); 190 pmd_populate_kernel(&init_mm, pmd, kasan_early_shadow_pte); 191 } while (pmd++, addr = next, addr != end); 192 } 193