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