kernel/2.6.29.6-aldebaran-rt/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 #include <asm/trampoline.h>
  28
  29 static void __init zap_identity_mappings(void)
  30 {
  31         pgd_t *pgd = pgd_offset_k(0UL);
  32         pgd_clear(pgd);
  33         /*
  34          * preempt_disable/enable does not work this early in the
  35          * bootup yet:
  36          */
  37         write_cr3(read_cr3());
  38 }
  39
  40 /* Don't add a printk in there. printk relies on the PDA which is not initialized
  41    yet. */
  42 static void __init clear_bss(void)
  43 {
  44         memset(__bss_start, 0,
  45                (unsigned long) __bss_stop - (unsigned long) __bss_start);
  46 }
  47
  48 static void __init copy_bootdata(char *real_mode_data)
  49 {
  50         char * command_line;
  51
  52         memcpy(&boot_params, real_mode_data, sizeof boot_params);
  53         if (boot_params.hdr.cmd_line_ptr) {
  54                 command_line = __va(boot_params.hdr.cmd_line_ptr);
  55                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
  56         }
  57 }
  58
  59 void __init x86_64_start_kernel(char * real_mode_data)
  60 {
  61         int i;
  62
  63         /*
  64          * Build-time sanity checks on the kernel image and module
  65          * area mappings. (these are purely build-time and produce no code)
  66          */
  67         BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
  68         BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
  69         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
  70         BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
  71         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
  72         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
  73         BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
  74                                 (__START_KERNEL & PGDIR_MASK)));
  75         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
  76
  77         /* clear bss before set_intr_gate with early_idt_handler */
  78         clear_bss();
  79
  80         /* Make NULL pointers segfault */
  81         zap_identity_mappings();
  82
  83         /* Cleanup the over mapped high alias */
  84         cleanup_highmap();
  85
  86         for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
  87 #ifdef CONFIG_EARLY_PRINTK
  88                 set_intr_gate(i, &early_idt_handlers[i]);
  89 #else
  90                 set_intr_gate(i, early_idt_handler);
  91 #endif
  92         }
  93         load_idt((const struct desc_ptr *)&idt_descr);
  94
  95         if (console_loglevel == 10)
  96                 early_printk("Kernel alive\n");
  97
  98         x86_64_start_reservations(real_mode_data);
  99 }
 100
 101 void __init x86_64_start_reservations(char *real_mode_data)
 102 {
 103         copy_bootdata(__va(real_mode_data));
 104
 105         reserve_trampoline_memory();
 106
 107         reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");
 108
 109 #ifdef CONFIG_BLK_DEV_INITRD
 110         /* Reserve INITRD */
 111         if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
 112                 unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
 113                 unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
 114                 unsigned long ramdisk_end   = ramdisk_image + ramdisk_size;
 115                 reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
 116         }
 117 #endif
 118
 119         reserve_ebda_region();
 120
 121         /*
 122          * At this point everything still needed from the boot loader
 123          * or BIOS or kernel text should be early reserved or marked not
 124          * RAM in e820. All other memory is free game.
 125          */
 126
 127         start_kernel();
 128 }