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