1 /* 2 * prepare to run common code 3 * 4 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE 5 */ 6 7 #define DISABLE_BRANCH_PROFILING 8 #include <linux/init.h> 9 #include <linux/linkage.h> 10 #include <linux/types.h> 11 #include <linux/kernel.h> 12 #include <linux/string.h> 13 #include <linux/percpu.h> 14 #include <linux/start_kernel.h> 15 #include <linux/io.h> 16 #include <linux/memblock.h> 17 18 #include <asm/processor.h> 19 #include <asm/proto.h> 20 #include <asm/smp.h> 21 #include <asm/setup.h> 22 #include <asm/desc.h> 23 #include <asm/pgtable.h> 24 #include <asm/tlbflush.h> 25 #include <asm/sections.h> 26 #include <asm/kdebug.h> 27 #include <asm/e820/api.h> 28 #include <asm/bios_ebda.h> 29 #include <asm/bootparam_utils.h> 30 #include <asm/microcode.h> 31 #include <asm/kasan.h> 32 33 /* 34 * Manage page tables very early on. 35 */ 36 extern pgd_t early_top_pgt[PTRS_PER_PGD]; 37 extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; 38 static unsigned int __initdata next_early_pgt; 39 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); 40 41 #define __head __section(.head.text) 42 43 static void __head *fixup_pointer(void *ptr, unsigned long physaddr) 44 { 45 return ptr - (void *)_text + (void *)physaddr; 46 } 47 48 void __head __startup_64(unsigned long physaddr) 49 { 50 unsigned long load_delta, *p; 51 pgdval_t *pgd; 52 p4dval_t *p4d; 53 pudval_t *pud; 54 pmdval_t *pmd, pmd_entry; 55 int i; 56 unsigned int *next_pgt_ptr; 57 58 /* Is the address too large? */ 59 if (physaddr >> MAX_PHYSMEM_BITS) 60 for (;;); 61 62 /* 63 * Compute the delta between the address I am compiled to run at 64 * and the address I am actually running at. 65 */ 66 load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map); 67 68 /* Is the address not 2M aligned? */ 69 if (load_delta & ~PMD_PAGE_MASK) 70 for (;;); 71 72 /* Fixup the physical addresses in the page table */ 73 74 pgd = fixup_pointer(&early_top_pgt, physaddr); 75 pgd[pgd_index(__START_KERNEL_map)] += load_delta; 76 77 if (IS_ENABLED(CONFIG_X86_5LEVEL)) { 78 p4d = fixup_pointer(&level4_kernel_pgt, physaddr); 79 p4d[511] += load_delta; 80 } 81 82 pud = fixup_pointer(&level3_kernel_pgt, physaddr); 83 pud[510] += load_delta; 84 pud[511] += load_delta; 85 86 pmd = fixup_pointer(level2_fixmap_pgt, physaddr); 87 pmd[506] += load_delta; 88 89 /* 90 * Set up the identity mapping for the switchover. These 91 * entries should *NOT* have the global bit set! This also 92 * creates a bunch of nonsense entries but that is fine -- 93 * it avoids problems around wraparound. 94 */ 95 next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr); 96 pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr); 97 pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr); 98 99 if (IS_ENABLED(CONFIG_X86_5LEVEL)) { 100 p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr); 101 102 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD; 103 pgd[i + 0] = (pgdval_t)p4d + _KERNPG_TABLE; 104 pgd[i + 1] = (pgdval_t)p4d + _KERNPG_TABLE; 105 106 i = (physaddr >> P4D_SHIFT) % PTRS_PER_P4D; 107 p4d[i + 0] = (pgdval_t)pud + _KERNPG_TABLE; 108 p4d[i + 1] = (pgdval_t)pud + _KERNPG_TABLE; 109 } else { 110 i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD; 111 pgd[i + 0] = (pgdval_t)pud + _KERNPG_TABLE; 112 pgd[i + 1] = (pgdval_t)pud + _KERNPG_TABLE; 113 } 114 115 i = (physaddr >> PUD_SHIFT) % PTRS_PER_PUD; 116 pud[i + 0] = (pudval_t)pmd + _KERNPG_TABLE; 117 pud[i + 1] = (pudval_t)pmd + _KERNPG_TABLE; 118 119 pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL; 120 pmd_entry += physaddr; 121 122 for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) { 123 int idx = i + (physaddr >> PMD_SHIFT) % PTRS_PER_PMD; 124 pmd[idx] = pmd_entry + i * PMD_SIZE; 125 } 126 127 /* 128 * Fixup the kernel text+data virtual addresses. Note that 129 * we might write invalid pmds, when the kernel is relocated 130 * cleanup_highmap() fixes this up along with the mappings 131 * beyond _end. 132 */ 133 134 pmd = fixup_pointer(level2_kernel_pgt, physaddr); 135 for (i = 0; i < PTRS_PER_PMD; i++) { 136 if (pmd[i] & _PAGE_PRESENT) 137 pmd[i] += load_delta; 138 } 139 140 /* Fixup phys_base */ 141 p = fixup_pointer(&phys_base, physaddr); 142 *p += load_delta; 143 } 144 145 /* Wipe all early page tables except for the kernel symbol map */ 146 static void __init reset_early_page_tables(void) 147 { 148 memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1)); 149 next_early_pgt = 0; 150 write_cr3(__pa_nodebug(early_top_pgt)); 151 } 152 153 /* Create a new PMD entry */ 154 int __init early_make_pgtable(unsigned long address) 155 { 156 unsigned long physaddr = address - __PAGE_OFFSET; 157 pgdval_t pgd, *pgd_p; 158 p4dval_t p4d, *p4d_p; 159 pudval_t pud, *pud_p; 160 pmdval_t pmd, *pmd_p; 161 162 /* Invalid address or early pgt is done ? */ 163 if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt)) 164 return -1; 165 166 again: 167 pgd_p = &early_top_pgt[pgd_index(address)].pgd; 168 pgd = *pgd_p; 169 170 /* 171 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is 172 * critical -- __PAGE_OFFSET would point us back into the dynamic 173 * range and we might end up looping forever... 174 */ 175 if (!IS_ENABLED(CONFIG_X86_5LEVEL)) 176 p4d_p = pgd_p; 177 else if (pgd) 178 p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 179 else { 180 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 181 reset_early_page_tables(); 182 goto again; 183 } 184 185 p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++]; 186 memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D); 187 *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 188 } 189 p4d_p += p4d_index(address); 190 p4d = *p4d_p; 191 192 if (p4d) 193 pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 194 else { 195 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 196 reset_early_page_tables(); 197 goto again; 198 } 199 200 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++]; 201 memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD); 202 *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 203 } 204 pud_p += pud_index(address); 205 pud = *pud_p; 206 207 if (pud) 208 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 209 else { 210 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 211 reset_early_page_tables(); 212 goto again; 213 } 214 215 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++]; 216 memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD); 217 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 218 } 219 pmd = (physaddr & PMD_MASK) + early_pmd_flags; 220 pmd_p[pmd_index(address)] = pmd; 221 222 return 0; 223 } 224 225 /* Don't add a printk in there. printk relies on the PDA which is not initialized 226 yet. */ 227 static void __init clear_bss(void) 228 { 229 memset(__bss_start, 0, 230 (unsigned long) __bss_stop - (unsigned long) __bss_start); 231 } 232 233 static unsigned long get_cmd_line_ptr(void) 234 { 235 unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr; 236 237 cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32; 238 239 return cmd_line_ptr; 240 } 241 242 static void __init copy_bootdata(char *real_mode_data) 243 { 244 char * command_line; 245 unsigned long cmd_line_ptr; 246 247 memcpy(&boot_params, real_mode_data, sizeof boot_params); 248 sanitize_boot_params(&boot_params); 249 cmd_line_ptr = get_cmd_line_ptr(); 250 if (cmd_line_ptr) { 251 command_line = __va(cmd_line_ptr); 252 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 253 } 254 } 255 256 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) 257 { 258 int i; 259 260 /* 261 * Build-time sanity checks on the kernel image and module 262 * area mappings. (these are purely build-time and produce no code) 263 */ 264 BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map); 265 BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE); 266 BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE); 267 BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0); 268 BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0); 269 BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); 270 BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == 271 (__START_KERNEL & PGDIR_MASK))); 272 BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); 273 274 cr4_init_shadow(); 275 276 /* Kill off the identity-map trampoline */ 277 reset_early_page_tables(); 278 279 clear_bss(); 280 281 clear_page(init_top_pgt); 282 283 kasan_early_init(); 284 285 for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) 286 set_intr_gate(i, early_idt_handler_array[i]); 287 load_idt((const struct desc_ptr *)&idt_descr); 288 289 copy_bootdata(__va(real_mode_data)); 290 291 /* 292 * Load microcode early on BSP. 293 */ 294 load_ucode_bsp(); 295 296 /* set init_top_pgt kernel high mapping*/ 297 init_top_pgt[511] = early_top_pgt[511]; 298 299 x86_64_start_reservations(real_mode_data); 300 } 301 302 void __init x86_64_start_reservations(char *real_mode_data) 303 { 304 /* version is always not zero if it is copied */ 305 if (!boot_params.hdr.version) 306 copy_bootdata(__va(real_mode_data)); 307 308 x86_early_init_platform_quirks(); 309 310 switch (boot_params.hdr.hardware_subarch) { 311 case X86_SUBARCH_INTEL_MID: 312 x86_intel_mid_early_setup(); 313 break; 314 default: 315 break; 316 } 317 318 start_kernel(); 319 } 320