arch/x86/kernel/head64.c

   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.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_level4_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 = 2;
  39 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
  40
  41 /* Wipe all early page tables except for the kernel symbol map */
  42 static void __init reset_early_page_tables(void)
  43 {
  44         unsigned long i;
  45
  46         for (i = 0; i < PTRS_PER_PGD-1; i++)
  47                 early_level4_pgt[i].pgd = 0;
  48
  49         next_early_pgt = 0;
  50
  51         write_cr3(__pa_nodebug(early_level4_pgt));
  52 }
  53
  54 /* Create a new PMD entry */
  55 int __init early_make_pgtable(unsigned long address)
  56 {
  57         unsigned long physaddr = address - __PAGE_OFFSET;
  58         unsigned long i;
  59         pgdval_t pgd, *pgd_p;
  60         pudval_t pud, *pud_p;
  61         pmdval_t pmd, *pmd_p;
  62
  63         /* Invalid address or early pgt is done ?  */
  64         if (physaddr >= MAXMEM || read_cr3() != __pa_nodebug(early_level4_pgt))
  65                 return -1;
  66
  67 again:
  68         pgd_p = &early_level4_pgt[pgd_index(address)].pgd;
  69         pgd = *pgd_p;
  70
  71         /*
  72          * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is
  73          * critical -- __PAGE_OFFSET would point us back into the dynamic
  74          * range and we might end up looping forever...
  75          */
  76         if (pgd)
  77                 pud_p = (pudval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
  78         else {
  79                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
  80                         reset_early_page_tables();
  81                         goto again;
  82                 }
  83
  84                 pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++];
  85                 for (i = 0; i < PTRS_PER_PUD; i++)
  86                         pud_p[i] = 0;
  87                 *pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
  88         }
  89         pud_p += pud_index(address);
  90         pud = *pud_p;
  91
  92         if (pud)
  93                 pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
  94         else {
  95                 if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) {
  96                         reset_early_page_tables();
  97                         goto again;
  98                 }
  99
 100                 pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++];
 101                 for (i = 0; i < PTRS_PER_PMD; i++)
 102                         pmd_p[i] = 0;
 103                 *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE;
 104         }
 105         pmd = (physaddr & PMD_MASK) + early_pmd_flags;
 106         pmd_p[pmd_index(address)] = pmd;
 107
 108         return 0;
 109 }
 110
 111 /* Don't add a printk in there. printk relies on the PDA which is not initialized
 112    yet. */
 113 static void __init clear_bss(void)
 114 {
 115         memset(__bss_start, 0,
 116                (unsigned long) __bss_stop - (unsigned long) __bss_start);
 117 }
 118
 119 static unsigned long get_cmd_line_ptr(void)
 120 {
 121         unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
 122
 123         cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
 124
 125         return cmd_line_ptr;
 126 }
 127
 128 static void __init copy_bootdata(char *real_mode_data)
 129 {
 130         char * command_line;
 131         unsigned long cmd_line_ptr;
 132
 133         memcpy(&boot_params, real_mode_data, sizeof boot_params);
 134         sanitize_boot_params(&boot_params);
 135         cmd_line_ptr = get_cmd_line_ptr();
 136         if (cmd_line_ptr) {
 137                 command_line = __va(cmd_line_ptr);
 138                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 139         }
 140 }
 141
 142 asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
 143 {
 144         int i;
 145
 146         /*
 147          * Build-time sanity checks on the kernel image and module
 148          * area mappings. (these are purely build-time and produce no code)
 149          */
 150         BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map);
 151         BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE);
 152         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
 153         BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0);
 154         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
 155         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
 156         BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
 157                                 (__START_KERNEL & PGDIR_MASK)));
 158         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
 159
 160         cr4_init_shadow();
 161
 162         /* Kill off the identity-map trampoline */
 163         reset_early_page_tables();
 164
 165         clear_bss();
 166
 167         clear_page(init_level4_pgt);
 168
 169         kasan_early_init();
 170
 171         for (i = 0; i < NUM_EXCEPTION_VECTORS; i++)
 172                 set_intr_gate(i, early_idt_handler_array[i]);
 173         load_idt((const struct desc_ptr *)&idt_descr);
 174
 175         copy_bootdata(__va(real_mode_data));
 176
 177         /*
 178          * Load microcode early on BSP.
 179          */
 180         load_ucode_bsp();
 181
 182         /* set init_level4_pgt kernel high mapping*/
 183         init_level4_pgt[511] = early_level4_pgt[511];
 184
 185         x86_64_start_reservations(real_mode_data);
 186 }
 187
 188 void __init x86_64_start_reservations(char *real_mode_data)
 189 {
 190         /* version is always not zero if it is copied */
 191         if (!boot_params.hdr.version)
 192                 copy_bootdata(__va(real_mode_data));
 193
 194         reserve_ebda_region();
 195
 196         start_kernel();
 197 }