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_P4D_FOLDED 17 #define __pgd_none(early, pgd) (0) 18 #else 19 #define __pgd_none(early, pgd) (early ? (pgd_val(pgd) == 0) : \ 20 (__pa(pgd_val(pgd)) == (unsigned long)__pa(kasan_early_shadow_p4d))) 21 #endif 22 23 #ifdef __PAGETABLE_PUD_FOLDED 24 #define __p4d_none(early, p4d) (0) 25 #else 26 #define __p4d_none(early, p4d) (early ? (p4d_val(p4d) == 0) : \ 27 (__pa(p4d_val(p4d)) == (unsigned long)__pa(kasan_early_shadow_pud))) 28 #endif 29 30 #ifdef __PAGETABLE_PMD_FOLDED 31 #define __pud_none(early, pud) (0) 32 #else 33 #define __pud_none(early, pud) (early ? (pud_val(pud) == 0) : \ 34 (__pa(pud_val(pud)) == (unsigned long)__pa(kasan_early_shadow_pmd))) 35 #endif 36 37 #define __pmd_none(early, pmd) (early ? (pmd_val(pmd) == 0) : \ 38 (__pa(pmd_val(pmd)) == (unsigned long)__pa(kasan_early_shadow_pte))) 39 40 #define __pte_none(early, pte) (early ? pte_none(pte) : \ 41 ((pte_val(pte) & _PFN_MASK) == (unsigned long)__pa(kasan_early_shadow_page))) 42 43 void *kasan_mem_to_shadow(const void *addr) 44 { 45 if (!kasan_enabled()) { 46 return (void *)(kasan_early_shadow_page); 47 } else { 48 unsigned long maddr = (unsigned long)addr; 49 unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff; 50 unsigned long offset = 0; 51 52 if (maddr >= FIXADDR_START) 53 return (void *)(kasan_early_shadow_page); 54 55 maddr &= XRANGE_SHADOW_MASK; 56 switch (xrange) { 57 case XKPRANGE_CC_SEG: 58 offset = XKPRANGE_CC_SHADOW_OFFSET; 59 break; 60 case XKPRANGE_UC_SEG: 61 offset = XKPRANGE_UC_SHADOW_OFFSET; 62 break; 63 case XKPRANGE_WC_SEG: 64 offset = XKPRANGE_WC_SHADOW_OFFSET; 65 break; 66 case XKVRANGE_VC_SEG: 67 offset = XKVRANGE_VC_SHADOW_OFFSET; 68 break; 69 default: 70 WARN_ON(1); 71 return NULL; 72 } 73 74 return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset); 75 } 76 } 77 78 const void *kasan_shadow_to_mem(const void *shadow_addr) 79 { 80 unsigned long addr = (unsigned long)shadow_addr; 81 82 if (unlikely(addr > KASAN_SHADOW_END) || 83 unlikely(addr < KASAN_SHADOW_START)) { 84 WARN_ON(1); 85 return NULL; 86 } 87 88 if (addr >= XKVRANGE_VC_SHADOW_OFFSET) 89 return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START); 90 else if (addr >= XKPRANGE_WC_SHADOW_OFFSET) 91 return (void *)(((addr - XKPRANGE_WC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_WC_START); 92 else if (addr >= XKPRANGE_UC_SHADOW_OFFSET) 93 return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START); 94 else if (addr >= XKPRANGE_CC_SHADOW_OFFSET) 95 return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START); 96 else { 97 WARN_ON(1); 98 return NULL; 99 } 100 } 101 102 /* 103 * Alloc memory for shadow memory page table. 104 */ 105 static phys_addr_t __init kasan_alloc_zeroed_page(int node) 106 { 107 void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE, 108 __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node); 109 if (!p) 110 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n", 111 __func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS)); 112 113 return __pa(p); 114 } 115 116 static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early) 117 { 118 if (__pmd_none(early, pmdp_get(pmdp))) { 119 phys_addr_t pte_phys = early ? 120 __pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node); 121 if (!early) 122 memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte)); 123 pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys)); 124 } 125 126 return pte_offset_kernel(pmdp, addr); 127 } 128 129 static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, bool early) 130 { 131 if (__pud_none(early, pudp_get(pudp))) { 132 phys_addr_t pmd_phys = early ? 133 __pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node); 134 if (!early) 135 memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd)); 136 pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys)); 137 } 138 139 return pmd_offset(pudp, addr); 140 } 141 142 static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early) 143 { 144 if (__p4d_none(early, p4dp_get(p4dp))) { 145 phys_addr_t pud_phys = early ? 146 __pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node); 147 if (!early) 148 memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud)); 149 p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys)); 150 } 151 152 return pud_offset(p4dp, addr); 153 } 154 155 static p4d_t *__init kasan_p4d_offset(pgd_t *pgdp, unsigned long addr, int node, bool early) 156 { 157 if (__pgd_none(early, pgdp_get(pgdp))) { 158 phys_addr_t p4d_phys = early ? 159 __pa_symbol(kasan_early_shadow_p4d) : kasan_alloc_zeroed_page(node); 160 if (!early) 161 memcpy(__va(p4d_phys), kasan_early_shadow_p4d, sizeof(kasan_early_shadow_p4d)); 162 pgd_populate(&init_mm, pgdp, (p4d_t *)__va(p4d_phys)); 163 } 164 165 return p4d_offset(pgdp, addr); 166 } 167 168 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr, 169 unsigned long end, int node, bool early) 170 { 171 unsigned long next; 172 pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early); 173 174 do { 175 phys_addr_t page_phys = early ? 176 __pa_symbol(kasan_early_shadow_page) 177 : kasan_alloc_zeroed_page(node); 178 next = addr + PAGE_SIZE; 179 set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL)); 180 } while (ptep++, addr = next, addr != end && __pte_none(early, ptep_get(ptep))); 181 } 182 183 static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr, 184 unsigned long end, int node, bool early) 185 { 186 unsigned long next; 187 pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early); 188 189 do { 190 next = pmd_addr_end(addr, end); 191 kasan_pte_populate(pmdp, addr, next, node, early); 192 } while (pmdp++, addr = next, addr != end && __pmd_none(early, pmdp_get(pmdp))); 193 } 194 195 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr, 196 unsigned long end, int node, bool early) 197 { 198 unsigned long next; 199 pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early); 200 201 do { 202 next = pud_addr_end(addr, end); 203 kasan_pmd_populate(pudp, addr, next, node, early); 204 } while (pudp++, addr = next, addr != end && __pud_none(early, READ_ONCE(*pudp))); 205 } 206 207 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr, 208 unsigned long end, int node, bool early) 209 { 210 unsigned long next; 211 p4d_t *p4dp = kasan_p4d_offset(pgdp, addr, node, early); 212 213 do { 214 next = p4d_addr_end(addr, end); 215 kasan_pud_populate(p4dp, addr, next, node, early); 216 } while (p4dp++, addr = next, addr != end && __p4d_none(early, READ_ONCE(*p4dp))); 217 } 218 219 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end, 220 int node, bool early) 221 { 222 unsigned long next; 223 pgd_t *pgdp; 224 225 pgdp = pgd_offset_k(addr); 226 227 do { 228 next = pgd_addr_end(addr, end); 229 kasan_p4d_populate(pgdp, addr, next, node, early); 230 } while (pgdp++, addr = next, addr != end); 231 232 } 233 234 /* Set up full kasan mappings, ensuring that the mapped pages are zeroed */ 235 static void __init kasan_map_populate(unsigned long start, unsigned long end, 236 int node) 237 { 238 kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false); 239 } 240 241 asmlinkage void __init kasan_early_init(void) 242 { 243 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE)); 244 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END + 1, PGDIR_SIZE)); 245 } 246 247 static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval) 248 { 249 WRITE_ONCE(*pgdp, pgdval); 250 } 251 252 static void __init clear_pgds(unsigned long start, unsigned long end) 253 { 254 /* 255 * Remove references to kasan page tables from 256 * swapper_pg_dir. pgd_clear() can't be used 257 * here because it's nop on 2,3-level pagetable setups 258 */ 259 for (; start < end; start = pgd_addr_end(start, end)) 260 kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0)); 261 } 262 263 void __init kasan_init(void) 264 { 265 u64 i; 266 phys_addr_t pa_start, pa_end; 267 268 /* 269 * If PGDIR_SIZE is too large for cpu_vabits, KASAN_SHADOW_END will 270 * overflow UINTPTR_MAX and then looks like a user space address. 271 * For example, PGDIR_SIZE of CONFIG_4KB_4LEVEL is 2^39, which is too 272 * large for Loongson-2K series whose cpu_vabits = 39. 273 */ 274 if (KASAN_SHADOW_END < vm_map_base) { 275 pr_warn("PGDIR_SIZE too large for cpu_vabits, KernelAddressSanitizer disabled.\n"); 276 return; 277 } 278 279 /* 280 * PGD was populated as invalid_pmd_table or invalid_pud_table 281 * in pagetable_init() which depends on how many levels of page 282 * table you are using, but we had to clean the gpd of kasan 283 * shadow memory, as the pgd value is none-zero. 284 * The assertion pgd_none is going to be false and the formal populate 285 * afterwards is not going to create any new pgd at all. 286 */ 287 memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir)); 288 csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH); 289 local_flush_tlb_all(); 290 291 clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); 292 293 /* Maps everything to a single page of zeroes */ 294 kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true); 295 296 kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START), 297 kasan_mem_to_shadow((void *)KFENCE_AREA_END)); 298 299 /* Enable KASAN here before kasan_mem_to_shadow(). */ 300 kasan_init_generic(); 301 302 /* Populate the linear mapping */ 303 for_each_mem_range(i, &pa_start, &pa_end) { 304 void *start = (void *)phys_to_virt(pa_start); 305 void *end = (void *)phys_to_virt(pa_end); 306 307 if (start >= end) 308 break; 309 310 kasan_map_populate((unsigned long)kasan_mem_to_shadow(start), 311 (unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE); 312 } 313 314 /* Populate modules mapping */ 315 kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR), 316 (unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE); 317 /* 318 * KAsan may reuse the contents of kasan_early_shadow_pte directly, so we 319 * should make sure that it maps the zero page read-only. 320 */ 321 for (i = 0; i < PTRS_PER_PTE; i++) 322 set_pte(&kasan_early_shadow_pte[i], 323 pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO)); 324 325 memset(kasan_early_shadow_page, 0, PAGE_SIZE); 326 csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH); 327 local_flush_tlb_all(); 328 329 /* At this point kasan is fully initialized. Enable error messages */ 330 init_task.kasan_depth = 0; 331 } 332