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