1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * prepare to run common code 4 * 5 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE 6 */ 7 8 #define DISABLE_BRANCH_PROFILING 9 #include <linux/init.h> 10 #include <linux/linkage.h> 11 #include <linux/types.h> 12 #include <linux/kernel.h> 13 #include <linux/string.h> 14 #include <linux/percpu.h> 15 #include <linux/start_kernel.h> 16 #include <linux/io.h> 17 #include <linux/memblock.h> 18 #include <linux/mem_encrypt.h> 19 20 #include <asm/processor.h> 21 #include <asm/proto.h> 22 #include <asm/smp.h> 23 #include <asm/setup.h> 24 #include <asm/desc.h> 25 #include <asm/pgtable.h> 26 #include <asm/tlbflush.h> 27 #include <asm/sections.h> 28 #include <asm/kdebug.h> 29 #include <asm/e820/api.h> 30 #include <asm/bios_ebda.h> 31 #include <asm/bootparam_utils.h> 32 #include <asm/microcode.h> 33 #include <asm/kasan.h> 34 35 #ifdef CONFIG_X86_5LEVEL 36 #undef pgtable_l5_enabled 37 #define pgtable_l5_enabled __pgtable_l5_enabled 38 #endif 39 40 /* 41 * Manage page tables very early on. 42 */ 43 extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; 44 static unsigned int __initdata next_early_pgt; 45 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); 46 47 #ifdef CONFIG_X86_5LEVEL 48 unsigned int __pgtable_l5_enabled __ro_after_init; 49 EXPORT_SYMBOL(__pgtable_l5_enabled); 50 unsigned int pgdir_shift __ro_after_init = 39; 51 EXPORT_SYMBOL(pgdir_shift); 52 unsigned int ptrs_per_p4d __ro_after_init = 1; 53 EXPORT_SYMBOL(ptrs_per_p4d); 54 #endif 55 56 #ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT 57 unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4; 58 EXPORT_SYMBOL(page_offset_base); 59 unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4; 60 EXPORT_SYMBOL(vmalloc_base); 61 unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4; 62 EXPORT_SYMBOL(vmemmap_base); 63 #endif 64 65 #define __head __section(.head.text) 66 67 static void __head *fixup_pointer(void *ptr, unsigned long physaddr) 68 { 69 return ptr - (void *)_text + (void *)physaddr; 70 } 71 72 static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr) 73 { 74 return fixup_pointer(ptr, physaddr); 75 } 76 77 #ifdef CONFIG_X86_5LEVEL 78 static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr) 79 { 80 return fixup_pointer(ptr, physaddr); 81 } 82 83 static bool __head check_la57_support(unsigned long physaddr) 84 { 85 if (native_cpuid_eax(0) < 7) 86 return false; 87 88 if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) 89 return false; 90 91 *fixup_int(&pgtable_l5_enabled, physaddr) = 1; 92 *fixup_int(&pgdir_shift, physaddr) = 48; 93 *fixup_int(&ptrs_per_p4d, physaddr) = 512; 94 *fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5; 95 *fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5; 96 *fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE_L5; 97 98 return true; 99 } 100 #else 101 static bool __head check_la57_support(unsigned long physaddr) 102 { 103 return false; 104 } 105 #endif 106 107 unsigned long __head __startup_64(unsigned long physaddr, 108 struct boot_params *bp) 109 { 110 unsigned long load_delta, *p; 111 unsigned long pgtable_flags; 112 pgdval_t *pgd; 113 p4dval_t *p4d; 114 pudval_t *pud; 115 pmdval_t *pmd, pmd_entry; 116 bool la57; 117 int i; 118 unsigned int *next_pgt_ptr; 119 120 la57 = check_la57_support(physaddr); 121 122 /* Is the address too large? */ 123 if (physaddr >> MAX_PHYSMEM_BITS) 124 for (;;); 125 126 /* 127 * Compute the delta between the address I am compiled to run at 128 * and the address I am actually running at. 129 */ 130 load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map); 131 132 /* Is the address not 2M aligned? */ 133 if (load_delta & ~PMD_PAGE_MASK) 134 for (;;); 135 136 /* Activate Secure Memory Encryption (SME) if supported and enabled */ 137 sme_enable(bp); 138 139 /* Include the SME encryption mask in the fixup value */ 140 load_delta += sme_get_me_mask(); 141 142 /* Fixup the physical addresses in the page table */ 143 144 pgd = fixup_pointer(&early_top_pgt, physaddr); 145 p = pgd + pgd_index(__START_KERNEL_map); 146 if (la57) 147 *p = (unsigned long)level4_kernel_pgt; 148 else 149 *p = (unsigned long)level3_kernel_pgt; 150 *p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta; 151 152 if (la57) { 153 p4d = fixup_pointer(&level4_kernel_pgt, physaddr); 154 p4d[511] += load_delta; 155 } 156 157 pud = fixup_pointer(&level3_kernel_pgt, physaddr); 158 pud[510] += load_delta; 159 pud[511] += load_delta; 160 161 pmd = fixup_pointer(level2_fixmap_pgt, physaddr); 162 pmd[506] += load_delta; 163 164 /* 165 * Set up the identity mapping for the switchover. These 166 * entries should *NOT* have the global bit set! This also 167 * creates a bunch of nonsense entries but that is fine -- 168 * it avoids problems around wraparound. 169 */ 170 171 next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr); 172 pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr); 173 pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr); 174 175 pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask(); 176 177 if (la57) { 178 p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr); 179 180 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD; 181 pgd[i + 0] = (pgdval_t)p4d + pgtable_flags; 182 pgd[i + 1] = (pgdval_t)p4d + pgtable_flags; 183 184 i = (physaddr >> P4D_SHIFT) % PTRS_PER_P4D; 185 p4d[i + 0] = (pgdval_t)pud + pgtable_flags; 186 p4d[i + 1] = (pgdval_t)pud + pgtable_flags; 187 } else { 188 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD; 189 pgd[i + 0] = (pgdval_t)pud + pgtable_flags; 190 pgd[i + 1] = (pgdval_t)pud + pgtable_flags; 191 } 192 193 i = (physaddr >> PUD_SHIFT) % PTRS_PER_PUD; 194 pud[i + 0] = (pudval_t)pmd + pgtable_flags; 195 pud[i + 1] = (pudval_t)pmd + pgtable_flags; 196 197 pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL; 198 /* Filter out unsupported __PAGE_KERNEL_* bits: */ 199 pmd_entry &= __supported_pte_mask; 200 pmd_entry += sme_get_me_mask(); 201 pmd_entry += physaddr; 202 203 for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) { 204 int idx = i + (physaddr >> PMD_SHIFT) % PTRS_PER_PMD; 205 pmd[idx] = pmd_entry + i * PMD_SIZE; 206 } 207 208 /* 209 * Fixup the kernel text+data virtual addresses. Note that 210 * we might write invalid pmds, when the kernel is relocated 211 * cleanup_highmap() fixes this up along with the mappings 212 * beyond _end. 213 */ 214 215 pmd = fixup_pointer(level2_kernel_pgt, physaddr); 216 for (i = 0; i < PTRS_PER_PMD; i++) { 217 if (pmd[i] & _PAGE_PRESENT) 218 pmd[i] += load_delta; 219 } 220 221 /* 222 * Fixup phys_base - remove the memory encryption mask to obtain 223 * the true physical address. 224 */ 225 *fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask(); 226 227 /* Encrypt the kernel and related (if SME is active) */ 228 sme_encrypt_kernel(bp); 229 230 /* 231 * Return the SME encryption mask (if SME is active) to be used as a 232 * modifier for the initial pgdir entry programmed into CR3. 233 */ 234 return sme_get_me_mask(); 235 } 236 237 unsigned long __startup_secondary_64(void) 238 { 239 /* 240 * Return the SME encryption mask (if SME is active) to be used as a 241 * modifier for the initial pgdir entry programmed into CR3. 242 */ 243 return sme_get_me_mask(); 244 } 245 246 /* Wipe all early page tables except for the kernel symbol map */ 247 static void __init reset_early_page_tables(void) 248 { 249 memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1)); 250 next_early_pgt = 0; 251 write_cr3(__sme_pa_nodebug(early_top_pgt)); 252 } 253 254 /* Create a new PMD entry */ 255 int __init __early_make_pgtable(unsigned long address, pmdval_t pmd) 256 { 257 unsigned long physaddr = address - __PAGE_OFFSET; 258 pgdval_t pgd, *pgd_p; 259 p4dval_t p4d, *p4d_p; 260 pudval_t pud, *pud_p; 261 pmdval_t *pmd_p; 262 263 /* Invalid address or early pgt is done ? */ 264 if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt)) 265 return -1; 266 267 again: 268 pgd_p = &early_top_pgt[pgd_index(address)].pgd; 269 pgd = *pgd_p; 270 271 /* 272 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is 273 * critical -- __PAGE_OFFSET would point us back into the dynamic 274 * range and we might end up looping forever... 275 */ 276 if (!pgtable_l5_enabled) 277 p4d_p = pgd_p; 278 else if (pgd) 279 p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 280 else { 281 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 282 reset_early_page_tables(); 283 goto again; 284 } 285 286 p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++]; 287 memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D); 288 *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 289 } 290 p4d_p += p4d_index(address); 291 p4d = *p4d_p; 292 293 if (p4d) 294 pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 295 else { 296 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 297 reset_early_page_tables(); 298 goto again; 299 } 300 301 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++]; 302 memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD); 303 *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 304 } 305 pud_p += pud_index(address); 306 pud = *pud_p; 307 308 if (pud) 309 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 310 else { 311 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 312 reset_early_page_tables(); 313 goto again; 314 } 315 316 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++]; 317 memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD); 318 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 319 } 320 pmd_p[pmd_index(address)] = pmd; 321 322 return 0; 323 } 324 325 int __init early_make_pgtable(unsigned long address) 326 { 327 unsigned long physaddr = address - __PAGE_OFFSET; 328 pmdval_t pmd; 329 330 pmd = (physaddr & PMD_MASK) + early_pmd_flags; 331 332 return __early_make_pgtable(address, pmd); 333 } 334 335 /* Don't add a printk in there. printk relies on the PDA which is not initialized 336 yet. */ 337 static void __init clear_bss(void) 338 { 339 memset(__bss_start, 0, 340 (unsigned long) __bss_stop - (unsigned long) __bss_start); 341 } 342 343 static unsigned long get_cmd_line_ptr(void) 344 { 345 unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr; 346 347 cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32; 348 349 return cmd_line_ptr; 350 } 351 352 static void __init copy_bootdata(char *real_mode_data) 353 { 354 char * command_line; 355 unsigned long cmd_line_ptr; 356 357 /* 358 * If SME is active, this will create decrypted mappings of the 359 * boot data in advance of the copy operations. 360 */ 361 sme_map_bootdata(real_mode_data); 362 363 memcpy(&boot_params, real_mode_data, sizeof boot_params); 364 sanitize_boot_params(&boot_params); 365 cmd_line_ptr = get_cmd_line_ptr(); 366 if (cmd_line_ptr) { 367 command_line = __va(cmd_line_ptr); 368 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 369 } 370 371 /* 372 * The old boot data is no longer needed and won't be reserved, 373 * freeing up that memory for use by the system. If SME is active, 374 * we need to remove the mappings that were created so that the 375 * memory doesn't remain mapped as decrypted. 376 */ 377 sme_unmap_bootdata(real_mode_data); 378 } 379 380 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) 381 { 382 /* 383 * Build-time sanity checks on the kernel image and module 384 * area mappings. (these are purely build-time and produce no code) 385 */ 386 BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map); 387 BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE); 388 BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE); 389 BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0); 390 BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0); 391 BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); 392 MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == 393 (__START_KERNEL & PGDIR_MASK))); 394 BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); 395 396 cr4_init_shadow(); 397 398 /* Kill off the identity-map trampoline */ 399 reset_early_page_tables(); 400 401 clear_bss(); 402 403 clear_page(init_top_pgt); 404 405 /* 406 * SME support may update early_pmd_flags to include the memory 407 * encryption mask, so it needs to be called before anything 408 * that may generate a page fault. 409 */ 410 sme_early_init(); 411 412 kasan_early_init(); 413 414 idt_setup_early_handler(); 415 416 copy_bootdata(__va(real_mode_data)); 417 418 /* 419 * Load microcode early on BSP. 420 */ 421 load_ucode_bsp(); 422 423 /* set init_top_pgt kernel high mapping*/ 424 init_top_pgt[511] = early_top_pgt[511]; 425 426 x86_64_start_reservations(real_mode_data); 427 } 428 429 void __init x86_64_start_reservations(char *real_mode_data) 430 { 431 /* version is always not zero if it is copied */ 432 if (!boot_params.hdr.version) 433 copy_bootdata(__va(real_mode_data)); 434 435 x86_early_init_platform_quirks(); 436 437 switch (boot_params.hdr.hardware_subarch) { 438 case X86_SUBARCH_INTEL_MID: 439 x86_intel_mid_early_setup(); 440 break; 441 default: 442 break; 443 } 444 445 start_kernel(); 446 } 447