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
  14 #include <asm/processor.h>
  15 #include <asm/proto.h>
  16 #include <asm/smp.h>
  17 #include <asm/setup.h>
  18 #include <asm/desc.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/tlbflush.h>
  21 #include <asm/sections.h>
  22
  23 static void __init zap_identity_mappings(void)
  24 {
  25         pgd_t *pgd = pgd_offset_k(0UL);
  26         pgd_clear(pgd);
  27         __flush_tlb();
  28 }
  29
  30 /* Don't add a printk in there. printk relies on the PDA which is not initialized
  31    yet. */
  32 static void __init clear_bss(void)
  33 {
  34         memset(__bss_start, 0,
  35                (unsigned long) __bss_stop - (unsigned long) __bss_start);
  36 }
  37
  38 static void __init copy_bootdata(char *real_mode_data)
  39 {
  40         char * command_line;
  41
  42         memcpy(&boot_params, real_mode_data, sizeof boot_params);
  43         if (boot_params.hdr.cmd_line_ptr) {
  44                 command_line = __va(boot_params.hdr.cmd_line_ptr);
  45                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
  46         }
  47 }
  48
  49 void __init x86_64_start_kernel(char * real_mode_data)
  50 {
  51         int i;
  52
  53         /* clear bss before set_intr_gate with early_idt_handler */
  54         clear_bss();
  55
  56         /* Make NULL pointers segfault */
  57         zap_identity_mappings();
  58
  59         for (i = 0; i < IDT_ENTRIES; i++)
  60                 set_intr_gate(i, early_idt_handler);
  61         load_idt((const struct desc_ptr *)&idt_descr);
  62
  63         early_printk("Kernel alive\n");
  64
  65         for (i = 0; i < NR_CPUS; i++)
  66                 cpu_pda(i) = &boot_cpu_pda[i];
  67
  68         pda_init(0);
  69         copy_bootdata(__va(real_mode_data));
  70 #ifdef CONFIG_SMP
  71         cpu_set(0, cpu_online_map);
  72 #endif
  73         start_kernel();
  74 }