arch/x86/kernel/head64-xen.c

   1 /*
   2  *  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/start_kernel.h>
  17 #include <linux/io.h>
  18 #include <linux/memblock.h>
  19
  20 #include <asm/processor.h>
  21 #include <asm/proto.h>
  22 #include <asm/smp.h>
  23 #include <asm/setup.h>
  24 #include <asm/desc.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/tlbflush.h>
  27 #include <asm/sections.h>
  28 #include <asm/kdebug.h>
  29 #include <asm/e820.h>
  30 #include <asm/trampoline.h>
  31 #include <asm/bios_ebda.h>
  32
  33 #ifndef CONFIG_XEN
  34 static void __init zap_identity_mappings(void)
  35 {
  36         pgd_t *pgd = pgd_offset_k(0UL);
  37         pgd_clear(pgd);
  38         __flush_tlb_all();
  39 }
  40
  41 /* Don't add a printk in there. printk relies on the PDA which is not initialized
  42    yet. */
  43 static void __init clear_bss(void)
  44 {
  45         memset(__bss_start, 0,
  46                (unsigned long) __bss_stop - (unsigned long) __bss_start);
  47 }
  48 #endif
  49
  50 static void __init copy_bootdata(char *real_mode_data)
  51 {
  52 #ifndef CONFIG_XEN
  53         char * command_line;
  54
  55         memcpy(&boot_params, real_mode_data, sizeof boot_params);
  56         if (boot_params.hdr.cmd_line_ptr) {
  57                 command_line = __va(boot_params.hdr.cmd_line_ptr);
  58                 memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
  59         }
  60 #else
  61         int max_cmdline;
  62
  63         if ((max_cmdline = MAX_GUEST_CMDLINE) > COMMAND_LINE_SIZE)
  64                 max_cmdline = COMMAND_LINE_SIZE;
  65         memcpy(boot_command_line, xen_start_info->cmd_line, max_cmdline);
  66         boot_command_line[max_cmdline-1] = '\0';
  67 #endif
  68 }
  69
  70 #include <xen/interface/memory.h>
  71
  72 void __init x86_64_start_kernel(char * real_mode_data)
  73 {
  74         /*
  75          * Build-time sanity checks on the kernel image and module
  76          * area mappings. (these are purely build-time and produce no code)
  77          */
  78         BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
  79         BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
  80         BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
  81         BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
  82         BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
  83         BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
  84         BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
  85                                 (__START_KERNEL & PGDIR_MASK)));
  86         BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
  87
  88         xen_start_info = (struct start_info *)real_mode_data;
  89         xen_start_kernel();
  90
  91 #ifndef CONFIG_XEN
  92         /* clear bss before set_intr_gate with early_idt_handler */
  93         clear_bss();
  94
  95         /* Make NULL pointers segfault */
  96         zap_identity_mappings();
  97
  98         for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
  99 #ifdef CONFIG_EARLY_PRINTK
 100                 set_intr_gate(i, &early_idt_handlers[i]);
 101 #else
 102                 set_intr_gate(i, early_idt_handler);
 103 #endif
 104         }
 105         load_idt((const struct desc_ptr *)&idt_descr);
 106 #endif
 107
 108         if (console_loglevel == 10)
 109                 early_printk("Kernel alive\n");
 110
 111         xen_switch_pt();
 112
 113         x86_64_start_reservations(real_mode_data);
 114 }
 115
 116 void __init x86_64_start_reservations(char *real_mode_data)
 117 {
 118         copy_bootdata(__va(real_mode_data));
 119
 120         memblock_reserve(__pa_symbol(&_text),
 121                          __pa_symbol(&__bss_stop) - __pa_symbol(&_text));
 122
 123 #ifdef CONFIG_BLK_DEV_INITRD
 124         /* Reserve INITRD if needed. */
 125         if (xen_start_info->flags & SIF_MOD_START_PFN) {
 126                 reserve_pfn_range(xen_start_info->mod_start,
 127                                   PFN_UP(xen_start_info->mod_len));
 128                 xen_initrd_start = xen_start_info->mod_start << PAGE_SHIFT;
 129         } else if (xen_start_info->mod_start)
 130                 xen_initrd_start = __pa(xen_start_info->mod_start);
 131 #endif
 132
 133         if (xen_feature(XENFEAT_auto_translated_physmap))
 134                 xen_start_info->mfn_list = ~0UL;
 135         else if (xen_start_info->mfn_list < __START_KERNEL_map)
 136                 reserve_pfn_range(xen_start_info->first_p2m_pfn,
 137                                   xen_start_info->nr_p2m_frames);
 138
 139         /*
 140          * At this point everything still needed from the boot loader
 141          * or BIOS or kernel text should be early reserved or marked not
 142          * RAM in e820. All other memory is free game.
 143          */
 144
 145         start_kernel();
 146 }