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 bool kasan_early_stage = true; 44 45 void *kasan_mem_to_shadow(const void *addr) 46 { 47 if (!kasan_arch_is_ready()) { 48 return (void *)(kasan_early_shadow_page); 49 } else { 50 unsigned long maddr = (unsigned long)addr; 51 unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff; 52 unsigned long offset = 0; 53 54 if (maddr >= FIXADDR_START) 55 return (void *)(kasan_early_shadow_page); 56 57 maddr &= XRANGE_SHADOW_MASK; 58 switch (xrange) { 59 case XKPRANGE_CC_SEG: 60 offset = XKPRANGE_CC_SHADOW_OFFSET; 61 break; 62 case XKPRANGE_UC_SEG: 63 offset = XKPRANGE_UC_SHADOW_OFFSET; 64 break; 65 case XKPRANGE_WC_SEG: 66 offset = XKPRANGE_WC_SHADOW_OFFSET; 67 break; 68 case XKVRANGE_VC_SEG: 69 offset = XKVRANGE_VC_SHADOW_OFFSET; 70 break; 71 default: 72 WARN_ON(1); 73 return NULL; 74 } 75 76 return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset); 77 } 78 } 79 80 const void *kasan_shadow_to_mem(const void *shadow_addr) 81 { 82 unsigned long addr = (unsigned long)shadow_addr; 83 84 if (unlikely(addr > KASAN_SHADOW_END) || 85 unlikely(addr < KASAN_SHADOW_START)) { 86 WARN_ON(1); 87 return NULL; 88 } 89 90 if (addr >= XKVRANGE_VC_SHADOW_OFFSET) 91 return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START); 92 else if (addr >= XKPRANGE_WC_SHADOW_OFFSET) 93 return (void *)(((addr - XKPRANGE_WC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_WC_START); 94 else if (addr >= XKPRANGE_UC_SHADOW_OFFSET) 95 return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START); 96 else if (addr >= XKPRANGE_CC_SHADOW_OFFSET) 97 return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START); 98 else { 99 WARN_ON(1); 100 return NULL; 101 } 102 } 103 104 /* 105 * Alloc memory for shadow memory page table. 106 */ 107 static phys_addr_t __init kasan_alloc_zeroed_page(int node) 108 { 109 void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE, 110 __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node); 111 if (!p) 112 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n", 113 __func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS)); 114 115 return __pa(p); 116 } 117 118 static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early) 119 { 120 if (__pmd_none(early, pmdp_get(pmdp))) { 121 phys_addr_t pte_phys = early ? 122 __pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node); 123 if (!early) 124 memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte)); 125 pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys)); 126 } 127 128 return pte_offset_kernel(pmdp, addr); 129 } 130 131 static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, bool early) 132 { 133 if (__pud_none(early, pudp_get(pudp))) { 134 phys_addr_t pmd_phys = early ? 135 __pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node); 136 if (!early) 137 memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd)); 138 pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys)); 139 } 140 141 return pmd_offset(pudp, addr); 142 } 143 144 static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early) 145 { 146 if (__p4d_none(early, p4dp_get(p4dp))) { 147 phys_addr_t pud_phys = early ? 148 __pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node); 149 if (!early) 150 memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud)); 151 p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys)); 152 } 153 154 return pud_offset(p4dp, addr); 155 } 156 157 static p4d_t *__init kasan_p4d_offset(pgd_t *pgdp, unsigned long addr, int node, bool early) 158 { 159 if (__pgd_none(early, pgdp_get(pgdp))) { 160 phys_addr_t p4d_phys = early ? 161 __pa_symbol(kasan_early_shadow_p4d) : kasan_alloc_zeroed_page(node); 162 if (!early) 163 memcpy(__va(p4d_phys), kasan_early_shadow_p4d, sizeof(kasan_early_shadow_p4d)); 164 pgd_populate(&init_mm, pgdp, (p4d_t *)__va(p4d_phys)); 165 } 166 167 return p4d_offset(pgdp, addr); 168 } 169 170 static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr, 171 unsigned long end, int node, bool early) 172 { 173 unsigned long next; 174 pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early); 175 176 do { 177 phys_addr_t page_phys = early ? 178 __pa_symbol(kasan_early_shadow_page) 179 : kasan_alloc_zeroed_page(node); 180 next = addr + PAGE_SIZE; 181 set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL)); 182 } while (ptep++, addr = next, addr != end && __pte_none(early, ptep_get(ptep))); 183 } 184 185 static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr, 186 unsigned long end, int node, bool early) 187 { 188 unsigned long next; 189 pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early); 190 191 do { 192 next = pmd_addr_end(addr, end); 193 kasan_pte_populate(pmdp, addr, next, node, early); 194 } while (pmdp++, addr = next, addr != end && __pmd_none(early, pmdp_get(pmdp))); 195 } 196 197 static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr, 198 unsigned long end, int node, bool early) 199 { 200 unsigned long next; 201 pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early); 202 203 do { 204 next = pud_addr_end(addr, end); 205 kasan_pmd_populate(pudp, addr, next, node, early); 206 } while (pudp++, addr = next, addr != end && __pud_none(early, READ_ONCE(*pudp))); 207 } 208 209 static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr, 210 unsigned long end, int node, bool early) 211 { 212 unsigned long next; 213 p4d_t *p4dp = kasan_p4d_offset(pgdp, addr, node, early); 214 215 do { 216 next = p4d_addr_end(addr, end); 217 kasan_pud_populate(p4dp, addr, next, node, early); 218 } while (p4dp++, addr = next, addr != end && __p4d_none(early, READ_ONCE(*p4dp))); 219 } 220 221 static void __init kasan_pgd_populate(unsigned long addr, unsigned long end, 222 int node, bool early) 223 { 224 unsigned long next; 225 pgd_t *pgdp; 226 227 pgdp = pgd_offset_k(addr); 228 229 do { 230 next = pgd_addr_end(addr, end); 231 kasan_p4d_populate(pgdp, addr, next, node, early); 232 } while (pgdp++, addr = next, addr != end); 233 234 } 235 236 /* Set up full kasan mappings, ensuring that the mapped pages are zeroed */ 237 static void __init kasan_map_populate(unsigned long start, unsigned long end, 238 int node) 239 { 240 kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false); 241 } 242 243 asmlinkage void __init kasan_early_init(void) 244 { 245 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE)); 246 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END + 1, PGDIR_SIZE)); 247 } 248 249 static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval) 250 { 251 WRITE_ONCE(*pgdp, pgdval); 252 } 253 254 static void __init clear_pgds(unsigned long start, unsigned long end) 255 { 256 /* 257 * Remove references to kasan page tables from 258 * swapper_pg_dir. pgd_clear() can't be used 259 * here because it's nop on 2,3-level pagetable setups 260 */ 261 for (; start < end; start = pgd_addr_end(start, end)) 262 kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0)); 263 } 264 265 void __init kasan_init(void) 266 { 267 u64 i; 268 phys_addr_t pa_start, pa_end; 269 270 /* 271 * If PGDIR_SIZE is too large for cpu_vabits, KASAN_SHADOW_END will 272 * overflow UINTPTR_MAX and then looks like a user space address. 273 * For example, PGDIR_SIZE of CONFIG_4KB_4LEVEL is 2^39, which is too 274 * large for Loongson-2K series whose cpu_vabits = 39. 275 */ 276 if (KASAN_SHADOW_END < vm_map_base) { 277 pr_warn("PGDIR_SIZE too large for cpu_vabits, KernelAddressSanitizer disabled.\n"); 278 return; 279 } 280 281 /* 282 * PGD was populated as invalid_pmd_table or invalid_pud_table 283 * in pagetable_init() which depends on how many levels of page 284 * table you are using, but we had to clean the gpd of kasan 285 * shadow memory, as the pgd value is none-zero. 286 * The assertion pgd_none is going to be false and the formal populate 287 * afterwards is not going to create any new pgd at all. 288 */ 289 memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir)); 290 csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH); 291 local_flush_tlb_all(); 292 293 clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); 294 295 /* Maps everything to a single page of zeroes */ 296 kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true); 297 298 kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START), 299 kasan_mem_to_shadow((void *)KFENCE_AREA_END)); 300 301 kasan_early_stage = false; 302 303 /* Populate the linear mapping */ 304 for_each_mem_range(i, &pa_start, &pa_end) { 305 void *start = (void *)phys_to_virt(pa_start); 306 void *end = (void *)phys_to_virt(pa_end); 307 308 if (start >= end) 309 break; 310 311 kasan_map_populate((unsigned long)kasan_mem_to_shadow(start), 312 (unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE); 313 } 314 315 /* Populate modules mapping */ 316 kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR), 317 (unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE); 318 /* 319 * KAsan may reuse the contents of kasan_early_shadow_pte directly, so we 320 * should make sure that it maps the zero page read-only. 321 */ 322 for (i = 0; i < PTRS_PER_PTE; i++) 323 set_pte(&kasan_early_shadow_pte[i], 324 pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO)); 325 326 memset(kasan_early_shadow_page, 0, PAGE_SIZE); 327 csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH); 328 local_flush_tlb_all(); 329 330 /* At this point kasan is fully initialized. Enable error messages */ 331 init_task.kasan_depth = 0; 332 pr_info("KernelAddressSanitizer initialized.\n"); 333 } 334