1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2023 Loongson Technology Corporation Limited 4 */ 5 #define pr_fmt(fmt) "kasan: " fmt 6 #include <linux/kasan.h> 7 #include <linux/memblock.h> 8 #include <linux/sched/task.h> 9 10 #include <asm/tlbflush.h> 11 #include <asm/pgalloc.h> 12 #include <asm-generic/sections.h> 13 14 static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); 15 16 #ifdef __PAGETABLE_PUD_FOLDED 17 #define __p4d_none(early, p4d) (0) 18 #else 19 #define __p4d_none(early, p4d) (early ? (p4d_val(p4d) == 0) : \ 20 (__pa(p4d_val(p4d)) == (unsigned long)__pa(kasan_early_shadow_pud))) 21 #endif 22 23 #ifdef __PAGETABLE_PMD_FOLDED 24 #define __pud_none(early, pud) (0) 25 #else 26 #define __pud_none(early, pud) (early ? (pud_val(pud) == 0) : \ 27 (__pa(pud_val(pud)) == (unsigned long)__pa(kasan_early_shadow_pmd))) 28 #endif 29 30 #define __pmd_none(early, pmd) (early ? (pmd_val(pmd) == 0) : \ 31 (__pa(pmd_val(pmd)) == (unsigned long)__pa(kasan_early_shadow_pte))) 32 33 #define __pte_none(early, pte) (early ? pte_none(pte) : \ 34 ((pte_val(pte) & _PFN_MASK) == (unsigned long)__pa(kasan_early_shadow_page))) 35 36 bool kasan_early_stage = true; 37 38 void *kasan_mem_to_shadow(const void *addr) 39 { 40 if (!kasan_arch_is_ready()) { 41 return (void *)(kasan_early_shadow_page); 42 } else { 43 unsigned long maddr = (unsigned long)addr; 44 unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff; 45 unsigned long offset = 0; 46 47 maddr &= XRANGE_SHADOW_MASK; 48 switch (xrange) { 49 case XKPRANGE_CC_SEG: 50 offset = XKPRANGE_CC_SHADOW_OFFSET; 51 break; 52 case XKPRANGE_UC_SEG: 53 offset = XKPRANGE_UC_SHADOW_OFFSET; 54 break; 55 case XKVRANGE_VC_SEG: 56 offset = XKVRANGE_VC_SHADOW_OFFSET; 57 break; 58 default: 59 WARN_ON(1); 60 return NULL; 61 } 62 63 return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset); 64 } 65 } 66 67 const void *kasan_shadow_to_mem(const void *shadow_addr) 68 { 69 unsigned long addr = (unsigned long)shadow_addr; 70 71 if (unlikely(addr > KASAN_SHADOW_END) || 72 unlikely(addr < KASAN_SHADOW_START)) { 73 WARN_ON(1); 74 return NULL; 75 } 76 77 if (addr >= XKVRANGE_VC_SHADOW_OFFSET) 78 return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START); 79 else if (addr >= XKPRANGE_UC_SHADOW_OFFSET) 80 return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START); 81 else if (addr >= XKPRANGE_CC_SHADOW_OFFSET) 82 return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START); 83 else { 84 WARN_ON(1); 85 return NULL; 86 } 87 } 88 89 /* 90 * Alloc memory for shadow memory page table. 91 */ 92 static phys_addr_t __init kasan_alloc_zeroed_page(int node) 93 { 94 void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE, 95 __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node); 96 if (!p) 97 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n", 98 __func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS)); 99 100 return __pa(p); 101 } 102 103 static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early) 104 { 105 if (__pmd_none(early, READ_ONCE(*pmdp))) { 106 phys_addr_t pte_phys = early ? 107 __pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node); 108 if (!early) 109 memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte)); 110 pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys)); 111 } 112 113 return pte_offset_kernel(pmdp, addr); 114 } 115 116 static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, bool early) 117 { 118 if (__pud_none(early, READ_ONCE(*pudp))) { 119 phys_addr_t pmd_phys = early ? 120 __pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node); 121 if (!early) 122 memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd)); 123 pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys)); 124 } 125 126 return pmd_offset(pudp, addr); 127 } 128 129 static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early) 130 { 131 if (__p4d_none(early, READ_ONCE(*p4dp))) { 132 phys_addr_t pud_phys = early ? 133 __pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node); 134 if (!early) 135 memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud)); 136 p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys)); 137 } 138 139 return pud_offset(p4dp, addr); 140 } 141 142 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr, 143 unsigned long end, int node, bool early) 144 { 145 unsigned long next; 146 pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early); 147 148 do { 149 phys_addr_t page_phys = early ? 150 __pa_symbol(kasan_early_shadow_page) 151 : kasan_alloc_zeroed_page(node); 152 next = addr + PAGE_SIZE; 153 set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL)); 154 } while (ptep++, addr = next, addr != end && __pte_none(early, READ_ONCE(*ptep))); 155 } 156 157 static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr, 158 unsigned long end, int node, bool early) 159 { 160 unsigned long next; 161 pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early); 162 163 do { 164 next = pmd_addr_end(addr, end); 165 kasan_pte_populate(pmdp, addr, next, node, early); 166 } while (pmdp++, addr = next, addr != end && __pmd_none(early, READ_ONCE(*pmdp))); 167 } 168 169 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr, 170 unsigned long end, int node, bool early) 171 { 172 unsigned long next; 173 pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early); 174 175 do { 176 next = pud_addr_end(addr, end); 177 kasan_pmd_populate(pudp, addr, next, node, early); 178 } while (pudp++, addr = next, addr != end); 179 } 180 181 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr, 182 unsigned long end, int node, bool early) 183 { 184 unsigned long next; 185 p4d_t *p4dp = p4d_offset(pgdp, addr); 186 187 do { 188 next = p4d_addr_end(addr, end); 189 kasan_pud_populate(p4dp, addr, next, node, early); 190 } while (p4dp++, addr = next, addr != end); 191 } 192 193 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end, 194 int node, bool early) 195 { 196 unsigned long next; 197 pgd_t *pgdp; 198 199 pgdp = pgd_offset_k(addr); 200 201 do { 202 next = pgd_addr_end(addr, end); 203 kasan_p4d_populate(pgdp, addr, next, node, early); 204 } while (pgdp++, addr = next, addr != end); 205 206 } 207 208 /* Set up full kasan mappings, ensuring that the mapped pages are zeroed */ 209 static void __init kasan_map_populate(unsigned long start, unsigned long end, 210 int node) 211 { 212 kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false); 213 } 214 215 asmlinkage void __init kasan_early_init(void) 216 { 217 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE)); 218 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE)); 219 } 220 221 static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval) 222 { 223 WRITE_ONCE(*pgdp, pgdval); 224 } 225 226 static void __init clear_pgds(unsigned long start, unsigned long end) 227 { 228 /* 229 * Remove references to kasan page tables from 230 * swapper_pg_dir. pgd_clear() can't be used 231 * here because it's nop on 2,3-level pagetable setups 232 */ 233 for (; start < end; start += PGDIR_SIZE) 234 kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0)); 235 } 236 237 void __init kasan_init(void) 238 { 239 u64 i; 240 phys_addr_t pa_start, pa_end; 241 242 /* 243 * PGD was populated as invalid_pmd_table or invalid_pud_table 244 * in pagetable_init() which depends on how many levels of page 245 * table you are using, but we had to clean the gpd of kasan 246 * shadow memory, as the pgd value is none-zero. 247 * The assertion pgd_none is going to be false and the formal populate 248 * afterwards is not going to create any new pgd at all. 249 */ 250 memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir)); 251 csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH); 252 local_flush_tlb_all(); 253 254 clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); 255 256 /* Maps everything to a single page of zeroes */ 257 kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true); 258 259 kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START), 260 kasan_mem_to_shadow((void *)KFENCE_AREA_END)); 261 262 kasan_early_stage = false; 263 264 /* Populate the linear mapping */ 265 for_each_mem_range(i, &pa_start, &pa_end) { 266 void *start = (void *)phys_to_virt(pa_start); 267 void *end = (void *)phys_to_virt(pa_end); 268 269 if (start >= end) 270 break; 271 272 kasan_map_populate((unsigned long)kasan_mem_to_shadow(start), 273 (unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE); 274 } 275 276 /* Populate modules mapping */ 277 kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR), 278 (unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE); 279 /* 280 * KAsan may reuse the contents of kasan_early_shadow_pte directly, so we 281 * should make sure that it maps the zero page read-only. 282 */ 283 for (i = 0; i < PTRS_PER_PTE; i++) 284 set_pte(&kasan_early_shadow_pte[i], 285 pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO)); 286 287 memset(kasan_early_shadow_page, 0, PAGE_SIZE); 288 csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH); 289 local_flush_tlb_all(); 290 291 /* At this point kasan is fully initialized. Enable error messages */ 292 init_task.kasan_depth = 0; 293 pr_info("KernelAddressSanitizer initialized.\n"); 294 } 295