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 memset(early_level4_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1)); 44 next_early_pgt = 0; 45 write_cr3(__pa_nodebug(early_level4_pgt)); 46 } 47 48 /* Create a new PMD entry */ 49 int __init early_make_pgtable(unsigned long address) 50 { 51 unsigned long physaddr = address - __PAGE_OFFSET; 52 pgdval_t pgd, *pgd_p; 53 pudval_t pud, *pud_p; 54 pmdval_t pmd, *pmd_p; 55 56 /* Invalid address or early pgt is done ? */ 57 if (physaddr >= MAXMEM || read_cr3() != __pa_nodebug(early_level4_pgt)) 58 return -1; 59 60 again: 61 pgd_p = &early_level4_pgt[pgd_index(address)].pgd; 62 pgd = *pgd_p; 63 64 /* 65 * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is 66 * critical -- __PAGE_OFFSET would point us back into the dynamic 67 * range and we might end up looping forever... 68 */ 69 if (pgd) 70 pud_p = (pudval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 71 else { 72 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 73 reset_early_page_tables(); 74 goto again; 75 } 76 77 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++]; 78 memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD); 79 *pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 80 } 81 pud_p += pud_index(address); 82 pud = *pud_p; 83 84 if (pud) 85 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); 86 else { 87 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { 88 reset_early_page_tables(); 89 goto again; 90 } 91 92 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++]; 93 memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD); 94 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; 95 } 96 pmd = (physaddr & PMD_MASK) + early_pmd_flags; 97 pmd_p[pmd_index(address)] = pmd; 98 99 return 0; 100 } 101 102 /* Don't add a printk in there. printk relies on the PDA which is not initialized 103 yet. */ 104 static void __init clear_bss(void) 105 { 106 memset(__bss_start, 0, 107 (unsigned long) __bss_stop - (unsigned long) __bss_start); 108 } 109 110 static unsigned long get_cmd_line_ptr(void) 111 { 112 unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr; 113 114 cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32; 115 116 return cmd_line_ptr; 117 } 118 119 static void __init copy_bootdata(char *real_mode_data) 120 { 121 char * command_line; 122 unsigned long cmd_line_ptr; 123 124 memcpy(&boot_params, real_mode_data, sizeof boot_params); 125 sanitize_boot_params(&boot_params); 126 cmd_line_ptr = get_cmd_line_ptr(); 127 if (cmd_line_ptr) { 128 command_line = __va(cmd_line_ptr); 129 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 130 } 131 } 132 133 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) 134 { 135 int i; 136 137 /* 138 * Build-time sanity checks on the kernel image and module 139 * area mappings. (these are purely build-time and produce no code) 140 */ 141 BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map); 142 BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE); 143 BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE); 144 BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0); 145 BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0); 146 BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); 147 BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == 148 (__START_KERNEL & PGDIR_MASK))); 149 BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); 150 151 cr4_init_shadow(); 152 153 /* Kill off the identity-map trampoline */ 154 reset_early_page_tables(); 155 156 clear_bss(); 157 158 clear_page(init_level4_pgt); 159 160 kasan_early_init(); 161 162 for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) 163 set_intr_gate(i, early_idt_handler_array[i]); 164 load_idt((const struct desc_ptr *)&idt_descr); 165 166 copy_bootdata(__va(real_mode_data)); 167 168 /* 169 * Load microcode early on BSP. 170 */ 171 load_ucode_bsp(); 172 173 /* set init_level4_pgt kernel high mapping*/ 174 init_level4_pgt[511] = early_level4_pgt[511]; 175 176 x86_64_start_reservations(real_mode_data); 177 } 178 179 void __init x86_64_start_reservations(char *real_mode_data) 180 { 181 /* version is always not zero if it is copied */ 182 if (!boot_params.hdr.version) 183 copy_bootdata(__va(real_mode_data)); 184 185 x86_early_init_platform_quirks(); 186 reserve_ebda_region(); 187 188 switch (boot_params.hdr.hardware_subarch) { 189 case X86_SUBARCH_INTEL_MID: 190 x86_intel_mid_early_setup(); 191 break; 192 default: 193 break; 194 } 195 196 start_kernel(); 197 } 198