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