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