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  *  Jun Nakajima <jun.nakajima@intel.com>
   7  *      Modified for Xen.
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/linkage.h>
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/percpu.h>
  16 #include <linux/module.h>
  17
  18 #include <asm/processor.h>
  19 #include <asm/proto.h>
  20 #include <asm/smp.h>
  21 #include <asm/bootsetup.h>
  22 #include <asm/setup.h>
  23 #include <asm/desc.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/sections.h>
  26
  27 #ifdef CONFIG_XEN
  28 unsigned long start_pfn;
  29 #endif
  30
  31 /* Don't add a printk in there. printk relies on the PDA which is not initialized
  32    yet. */
  33 #ifndef CONFIG_XEN
  34 static void __init clear_bss(void)
  35 {
  36         memset(__bss_start, 0,
  37                (unsigned long) __bss_stop - (unsigned long) __bss_start);
  38 }
  39 #endif
  40
  41 #define NEW_CL_POINTER          0x228   /* Relative to real mode data */
  42 #define OLD_CL_MAGIC_ADDR       0x90020
  43 #define OLD_CL_MAGIC            0xA33F
  44 #define OLD_CL_BASE_ADDR        0x90000
  45 #define OLD_CL_OFFSET           0x90022
  46
  47 extern char saved_command_line[];
  48
  49 static void __init copy_bootdata(char *real_mode_data)
  50 {
  51 #ifndef CONFIG_XEN
  52         int new_data;
  53         char * command_line;
  54
  55         memcpy(x86_boot_params, real_mode_data, BOOT_PARAM_SIZE);
  56         new_data = *(int *) (x86_boot_params + NEW_CL_POINTER);
  57         if (!new_data) {
  58                 if (OLD_CL_MAGIC != * (u16 *) OLD_CL_MAGIC_ADDR) {
  59                         return;
  60                 }
  61                 new_data = OLD_CL_BASE_ADDR + * (u16 *) OLD_CL_OFFSET;
  62         }
  63         command_line = (char *) ((u64)(new_data));
  64         memcpy(saved_command_line, command_line, COMMAND_LINE_SIZE);
  65 #else
  66         int max_cmdline;
  67
  68         if ((max_cmdline = MAX_GUEST_CMDLINE) > COMMAND_LINE_SIZE)
  69                 max_cmdline = COMMAND_LINE_SIZE;
  70         memcpy(saved_command_line, xen_start_info->cmd_line, max_cmdline);
  71         saved_command_line[max_cmdline-1] = '\0';
  72 #endif
  73 }
  74
  75 #ifdef CONFIG_XEN
  76 #include <xen/interface/memory.h>
  77 unsigned long *machine_to_phys_mapping;
  78 EXPORT_SYMBOL(machine_to_phys_mapping);
  79 unsigned int machine_to_phys_order;
  80 EXPORT_SYMBOL(machine_to_phys_order);
  81 #endif
  82
  83 void __init x86_64_start_kernel(char * real_mode_data)
  84 {
  85 #ifdef CONFIG_XEN
  86         struct xen_machphys_mapping mapping;
  87         unsigned long machine_to_phys_nr_ents;
  88 #endif
  89         int i;
  90
  91 #ifdef CONFIG_XEN
  92         xen_start_info = (struct start_info *)real_mode_data;
  93         if (!xen_feature(XENFEAT_auto_translated_physmap)) {
  94                 phys_to_machine_mapping =
  95                         (unsigned long *)xen_start_info->mfn_list;
  96                 start_pfn = (__pa(xen_start_info->pt_base) >> PAGE_SHIFT) +
  97                         xen_start_info->nr_pt_frames;
  98         }
  99
 100         machine_to_phys_mapping = (unsigned long *)MACH2PHYS_VIRT_START;
 101         machine_to_phys_nr_ents = MACH2PHYS_NR_ENTRIES;
 102         if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
 103                 machine_to_phys_mapping = (unsigned long *)mapping.v_start;
 104                 machine_to_phys_nr_ents = mapping.max_mfn + 1;
 105         }
 106         while ((1UL << machine_to_phys_order) < machine_to_phys_nr_ents )
 107                 machine_to_phys_order++;
 108
 109 #else
 110         /* clear bss before set_intr_gate with early_idt_handler */
 111         clear_bss();
 112
 113         for (i = 0; i < IDT_ENTRIES; i++)
 114                 set_intr_gate(i, early_idt_handler);
 115         asm volatile("lidt %0" :: "m" (idt_descr));
 116 #endif /* CONFIG_XEN */
 117         early_printk("Kernel alive\n");
 118
 119 #ifndef CONFIG_XEN
 120         /*
 121          * switch to init_level4_pgt from boot_level4_pgt
 122          */
 123         memcpy(init_level4_pgt, boot_level4_pgt, PTRS_PER_PGD*sizeof(pgd_t));
 124         asm volatile("movq %0,%%cr3" :: "r" (__pa_symbol(&init_level4_pgt)));
 125 #endif
 126
 127         for (i = 0; i < NR_CPUS; i++)
 128                 cpu_pda(i) = &boot_cpu_pda[i];
 129
 130         pda_init(0);
 131         copy_bootdata(real_mode_data);
 132 #ifdef CONFIG_SMP
 133         cpu_set(0, cpu_online_map);
 134 #endif
 135         start_kernel();
 136 }