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/tlbflush.h>
22#include <asm/sections.h>
23
24static void __init zap_identity_mappings(void)
25{
26	pgd_t *pgd = pgd_offset_k(0UL);
27	pgd_clear(pgd);
28	__flush_tlb();
29}
30
31/* Don't add a printk in there. printk relies on the PDA which is not initialized
32   yet. */
33static void __init clear_bss(void)
34{
35	memset(__bss_start, 0,
36	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
37}
38
39#define NEW_CL_POINTER		0x228	/* Relative to real mode data */
40#define OLD_CL_MAGIC_ADDR	0x20
41#define OLD_CL_MAGIC            0xA33F
42#define OLD_CL_OFFSET           0x22
43
44static void __init copy_bootdata(char *real_mode_data)
45{
46	unsigned long new_data;
47	char * command_line;
48
49	memcpy(x86_boot_params, real_mode_data, BOOT_PARAM_SIZE);
50	new_data = *(u32 *) (x86_boot_params + NEW_CL_POINTER);
51	if (!new_data) {
52		if (OLD_CL_MAGIC != *(u16 *)(real_mode_data + OLD_CL_MAGIC_ADDR)) {
53			return;
54		}
55		new_data = __pa(real_mode_data) + *(u16 *)(real_mode_data + OLD_CL_OFFSET);
56	}
57	command_line = __va(new_data);
58	memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
59}
60
61void __init x86_64_start_kernel(char * real_mode_data)
62{
63	int i;
64
65	/* clear bss before set_intr_gate with early_idt_handler */
66	clear_bss();
67
68	/* Make NULL pointers segfault */
69	zap_identity_mappings();
70
71	for (i = 0; i < IDT_ENTRIES; i++)
72		set_intr_gate(i, early_idt_handler);
73	asm volatile("lidt %0" :: "m" (idt_descr));
74
75	early_printk("Kernel alive\n");
76
77 	for (i = 0; i < NR_CPUS; i++)
78 		cpu_pda(i) = &boot_cpu_pda[i];
79
80	pda_init(0);
81	copy_bootdata(__va(real_mode_data));
82#ifdef CONFIG_SMP
83	cpu_set(0, cpu_online_map);
84#endif
85	start_kernel();
86}
87