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
  16 #include <asm/processor.h>
  17 #include <asm/proto.h>
  18 #include <asm/smp.h>
  19 #include <asm/setup.h>
  20 #include <asm/desc.h>
  21 #include <asm/pgtable.h>
  22 #include <asm/tlbflush.h>
  23 #include <asm/sections.h>
  24 #include <asm/kdebug.h>
  25 #include <asm/e820.h>
  26 #include <asm/bios_ebda.h>
  27
  28 static void __init zap_identity_mappings(void)
  29 {
  30         pgd_t *pgd = pgd_offset_k(0UL);
  31         pgd_clear(pgd);
  32         __flush_tlb_all();
  33 }
  34
  35 /* Don't add a printk in there. printk relies on the PDA which is not initialized
  36    yet. */
  37 static void __init clear_bss(void)
  38 {
  39         memset(__bss_start, 0,
  40                (unsigned long) __bss_stop - (unsigned long) __bss_start);
  41 }
  42
  43 static void __init copy_bootdata(char *real_mode_data)
  44 {
  45         char * command_line;
  46
  47         memcpy(&boot_params, real_mode_data, sizeof boot_params);
  48         if (boot_params.hdr.cmd_line_ptr) {
  49                 command_line = __va(boot_params.hdr.cmd_line_ptr);
  50                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
  51         }
  52 }
  53
  54 void __init x86_64_start_kernel(char * real_mode_data)
  55 {
  56         int i;
  57
  58         /*
  59          * Build-time sanity checks on the kernel image and module
  60          * area mappings. (these are purely build-time and produce no code)
  61          */
  62         BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
  63         BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
  64         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
  65         BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
  66         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
  67         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
  68         BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
  69                                 (__START_KERNEL & PGDIR_MASK)));
  70
  71         /* clear bss before set_intr_gate with early_idt_handler */
  72         clear_bss();
  73
  74         /* Make NULL pointers segfault */
  75         zap_identity_mappings();
  76
  77         /* Cleanup the over mapped high alias */
  78         cleanup_highmap();
  79
  80         for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
  81 #ifdef CONFIG_EARLY_PRINTK
  82                 set_intr_gate(i, &early_idt_handlers[i]);
  83 #else
  84                 set_intr_gate(i, early_idt_handler);
  85 #endif
  86         }
  87         load_idt((const struct desc_ptr *)&idt_descr);
  88
  89         early_printk("Kernel alive\n");
  90
  91         for (i = 0; i < NR_CPUS; i++)
  92                 cpu_pda(i) = &boot_cpu_pda[i];
  93
  94         pda_init(0);
  95         copy_bootdata(__va(real_mode_data));
  96
  97         reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
  98
  99 #ifdef CONFIG_BLK_DEV_INITRD
 100         /* Reserve INITRD */
 101         if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
 102                 unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
 103                 unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
 104                 unsigned long ramdisk_end   = ramdisk_image + ramdisk_size;
 105                 reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
 106         }
 107 #endif
 108
 109         reserve_ebda_region();
 110         reserve_setup_data();
 111
 112         /*
 113          * At this point everything still needed from the boot loader
 114          * or BIOS or kernel text should be early reserved or marked not
 115          * RAM in e820. All other memory is free game.
 116          */
 117
 118         start_kernel();
 119 }