1 /* 2 * prepare to run common code 3 * 4 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE 5 */ 6 7 #include <linux/init.h> 8 #include <linux/linkage.h> 9 #include <linux/types.h> 10 #include <linux/kernel.h> 11 #include <linux/string.h> 12 #include <linux/percpu.h> 13 #include <linux/start_kernel.h> 14 #include <linux/io.h> 15 #include <linux/memblock.h> 16 17 #include <asm/processor.h> 18 #include <asm/proto.h> 19 #include <asm/smp.h> 20 #include <asm/setup.h> 21 #include <asm/desc.h> 22 #include <asm/pgtable.h> 23 #include <asm/tlbflush.h> 24 #include <asm/sections.h> 25 #include <asm/kdebug.h> 26 #include <asm/e820.h> 27 #include <asm/bios_ebda.h> 28 #include <asm/bootparam_utils.h> 29 #include <asm/microcode.h> 30 #include <asm/kasan.h> 31 32 /* 33 * Manage page tables very early on. 34 */ 35 extern pgd_t early_level4_pgt[PTRS_PER_PGD]; 36 extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; 37 static unsigned int __initdata next_early_pgt = 2; 38 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); 39 40 /* Wipe all early page tables except for the kernel symbol map */ 41 static void __init reset_early_page_tables(void) 42 { 43 unsigned long i; 44 45 for (i = 0; i < PTRS_PER_PGD-1; i++) 46 early_level4_pgt[i].pgd = 0; 47 48 next_early_pgt = 0; 49 50 write_cr3(__pa_nodebug(early_level4_pgt)); 51 } 52 53 /* Create a new PMD entry */ 54 int __init early_make_pgtable(unsigned long address) 55 { 56 unsigned long physaddr = address - __PAGE_OFFSET; 57 unsigned long i; 58 pgdval_t pgd, *pgd_p; 59 pudval_t pud, *pud_p; 60 pmdval_t pmd, *pmd_p; 61 62 /* Invalid address or early pgt is done ? */ 63 if (physaddr >= MAXMEM || read_cr3() != __pa_nodebug(early_level4_pgt)) 64 return -1; 65 66 again: 67 pgd_p = &early_level4_pgt[pgd_index(address)].pgd; 68 pgd = *pgd_p; 69 70 /* 71 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is 72 * critical -- __PAGE_OFFSET would point us back into the dynamic 73 * range and we might end up looping forever... 74 */ 75 if (pgd) 76 pud_p = (pudval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 77 else { 78 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 79 reset_early_page_tables(); 80 goto again; 81 } 82 83 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++]; 84 for (i = 0; i < PTRS_PER_PUD; i++) 85 pud_p[i] = 0; 86 *pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 87 } 88 pud_p += pud_index(address); 89 pud = *pud_p; 90 91 if (pud) 92 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 93 else { 94 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 95 reset_early_page_tables(); 96 goto again; 97 } 98 99 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++]; 100 for (i = 0; i < PTRS_PER_PMD; i++) 101 pmd_p[i] = 0; 102 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 103 } 104 pmd = (physaddr & PMD_MASK) + early_pmd_flags; 105 pmd_p[pmd_index(address)] = pmd; 106 107 return 0; 108 } 109 110 /* Don't add a printk in there. printk relies on the PDA which is not initialized 111 yet. */ 112 static void __init clear_bss(void) 113 { 114 memset(__bss_start, 0, 115 (unsigned long) __bss_stop - (unsigned long) __bss_start); 116 } 117 118 static unsigned long get_cmd_line_ptr(void) 119 { 120 unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr; 121 122 cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32; 123 124 return cmd_line_ptr; 125 } 126 127 static void __init copy_bootdata(char *real_mode_data) 128 { 129 char * command_line; 130 unsigned long cmd_line_ptr; 131 132 memcpy(&boot_params, real_mode_data, sizeof boot_params); 133 sanitize_boot_params(&boot_params); 134 cmd_line_ptr = get_cmd_line_ptr(); 135 if (cmd_line_ptr) { 136 command_line = __va(cmd_line_ptr); 137 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 138 } 139 } 140 141 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) 142 { 143 int i; 144 145 /* 146 * Build-time sanity checks on the kernel image and module 147 * area mappings. (these are purely build-time and produce no code) 148 */ 149 BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map); 150 BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE); 151 BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE); 152 BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0); 153 BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0); 154 BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); 155 BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == 156 (__START_KERNEL & PGDIR_MASK))); 157 BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); 158 159 cr4_init_shadow(); 160 161 /* Kill off the identity-map trampoline */ 162 reset_early_page_tables(); 163 164 kasan_map_early_shadow(early_level4_pgt); 165 166 /* clear bss before set_intr_gate with early_idt_handler */ 167 clear_bss(); 168 169 for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) 170 set_intr_gate(i, early_idt_handlers[i]); 171 load_idt((const struct desc_ptr *)&idt_descr); 172 173 copy_bootdata(__va(real_mode_data)); 174 175 /* 176 * Load microcode early on BSP. 177 */ 178 load_ucode_bsp(); 179 180 clear_page(init_level4_pgt); 181 /* set init_level4_pgt kernel high mapping*/ 182 init_level4_pgt[511] = early_level4_pgt[511]; 183 184 kasan_map_early_shadow(init_level4_pgt); 185 186 x86_64_start_reservations(real_mode_data); 187 } 188 189 void __init x86_64_start_reservations(char *real_mode_data) 190 { 191 /* version is always not zero if it is copied */ 192 if (!boot_params.hdr.version) 193 copy_bootdata(__va(real_mode_data)); 194 195 reserve_ebda_region(); 196 197 start_kernel(); 198 } 199