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/trampoline.h>
  28 #include <asm/bios_ebda.h>
  29
  30 static void __init zap_identity_mappings(void)
  31 {
  32         pgd_t *pgd = pgd_offset_k(0UL);
  33         pgd_clear(pgd);
  34         __flush_tlb_all();
  35 }
  36
  37 /* Don't add a printk in there. printk relies on the PDA which is not initialized
  38    yet. */
  39 static void __init clear_bss(void)
  40 {
  41         memset(__bss_start, 0,
  42                (unsigned long) __bss_stop - (unsigned long) __bss_start);
  43 }
  44
  45 static void __init copy_bootdata(char *real_mode_data)
  46 {
  47         char * command_line;
  48
  49         memcpy(&boot_params, real_mode_data, sizeof boot_params);
  50         if (boot_params.hdr.cmd_line_ptr) {
  51                 command_line = __va(boot_params.hdr.cmd_line_ptr);
  52                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
  53         }
  54 }
  55
  56 void __init x86_64_start_kernel(char * real_mode_data)
  57 {
  58         int i;
  59
  60         /*
  61          * Build-time sanity checks on the kernel image and module
  62          * area mappings. (these are purely build-time and produce no code)
  63          */
  64         BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
  65         BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
  66         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
  67         BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
  68         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
  69         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
  70         BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
  71                                 (__START_KERNEL & PGDIR_MASK)));
  72         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
  73
  74         /* clear bss before set_intr_gate with early_idt_handler */
  75         clear_bss();
  76
  77         /* Make NULL pointers segfault */
  78         zap_identity_mappings();
  79
  80         max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT;
  81
  82         for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
  83 #ifdef CONFIG_EARLY_PRINTK
  84                 set_intr_gate(i, &early_idt_handlers[i]);
  85 #else
  86                 set_intr_gate(i, early_idt_handler);
  87 #endif
  88         }
  89         load_idt((const struct desc_ptr *)&idt_descr);
  90
  91         if (console_loglevel == 10)
  92                 early_printk("Kernel alive\n");
  93
  94         x86_64_start_reservations(real_mode_data);
  95 }
  96
  97 void __init x86_64_start_reservations(char *real_mode_data)
  98 {
  99         copy_bootdata(__va(real_mode_data));
 100
 101         memblock_reserve(__pa_symbol(&_text),
 102                          __pa_symbol(&__bss_stop) - __pa_symbol(&_text));
 103
 104 #ifdef CONFIG_BLK_DEV_INITRD
 105         /* Reserve INITRD */
 106         if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
 107                 /* Assume only end is not page aligned */
 108                 unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
 109                 unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
 110                 unsigned long ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
 111                 memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
 112         }
 113 #endif
 114
 115         reserve_ebda_region();
 116
 117         /*
 118          * At this point everything still needed from the boot loader
 119          * or BIOS or kernel text should be early reserved or marked not
 120          * RAM in e820. All other memory is free game.
 121          */
 122
 123         start_kernel();
 124 }