arch/x86_64/kernel/head64.c

   1 /*
   2  *  linux/arch/x86_64/kernel/head64.c -- 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
  14 #include <asm/processor.h>
  15 #include <asm/proto.h>
  16 #include <asm/smp.h>
  17 #include <asm/bootsetup.h>
  18 #include <asm/setup.h>
  19 #include <asm/desc.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/sections.h>
  22
  23 /* Don't add a printk in there. printk relies on the PDA which is not initialized
  24    yet. */
  25 static void __init clear_bss(void)
  26 {
  27         memset(__bss_start, 0,
  28                (unsigned long) __bss_stop - (unsigned long) __bss_start);
  29 }
  30
  31 #define NEW_CL_POINTER          0x228   /* Relative to real mode data */
  32 #define OLD_CL_MAGIC_ADDR       0x90020
  33 #define OLD_CL_MAGIC            0xA33F
  34 #define OLD_CL_BASE_ADDR        0x90000
  35 #define OLD_CL_OFFSET           0x90022
  36
  37 extern char saved_command_line[];
  38
  39 static void __init copy_bootdata(char *real_mode_data)
  40 {
  41         int new_data;
  42         char * command_line;
  43
  44         memcpy(x86_boot_params, real_mode_data, BOOT_PARAM_SIZE);
  45         new_data = *(int *) (x86_boot_params + NEW_CL_POINTER);
  46         if (!new_data) {
  47                 if (OLD_CL_MAGIC != * (u16 *) OLD_CL_MAGIC_ADDR) {
  48                         return;
  49                 }
  50                 new_data = OLD_CL_BASE_ADDR + * (u16 *) OLD_CL_OFFSET;
  51         }
  52         command_line = (char *) ((u64)(new_data));
  53         memcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
  54 }
  55
  56 void __init x86_64_start_kernel(char * real_mode_data)
  57 {
  58         int i;
  59
  60         for (i = 0; i < 256; i++)
  61                 set_intr_gate(i, early_idt_handler);
  62         asm volatile("lidt %0" :: "m" (idt_descr));
  63         clear_bss();
  64
  65         early_printk("Kernel alive\n");
  66
  67         /*
  68          * switch to init_level4_pgt from boot_level4_pgt
  69          */
  70         memcpy(init_level4_pgt, boot_level4_pgt, PTRS_PER_PGD*sizeof(pgd_t));
  71         asm volatile("movq %0,%%cr3" :: "r" (__pa_symbol(&init_level4_pgt)));
  72
  73         for (i = 0; i < NR_CPUS; i++)
  74                 cpu_pda(i) = &boot_cpu_pda[i];
  75
  76         pda_init(0);
  77         copy_bootdata(real_mode_data);
  78 #ifdef CONFIG_SMP
  79         cpu_set(0, cpu_online_map);
  80 #endif
  81         start_kernel();
  82 }