1 files changed, 86 insertions, 0 deletions
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
new file mode 100644
index 000000000000..6c34bdd22e26
--- /dev/null
+++ b/arch/x86/kernel/head64.c
@@ -0,0 +1,86 @@
+/*
+ *  linux/arch/x86_64/kernel/head64.c -- prepare to run common code
+ *
+ *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/percpu.h>
+
+#include <asm/processor.h>
+#include <asm/proto.h>
+#include <asm/smp.h>
+#include <asm/bootsetup.h>
+#include <asm/setup.h>
+#include <asm/desc.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+
+static void __init zap_identity_mappings(void)
+{
+	pgd_t *pgd = pgd_offset_k(0UL);
+	pgd_clear(pgd);
+	__flush_tlb();
+}
+
+/* Don't add a printk in there. printk relies on the PDA which is not initialized 
+   yet. */
+static void __init clear_bss(void)
+{
+	memset(__bss_start, 0,
+	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
+}
+
+#define NEW_CL_POINTER		0x228	/* Relative to real mode data */
+#define OLD_CL_MAGIC_ADDR	0x20
+#define OLD_CL_MAGIC            0xA33F
+#define OLD_CL_OFFSET           0x22
+
+static void __init copy_bootdata(char *real_mode_data)
+{
+	unsigned long new_data;
+	char * command_line;
+
+	memcpy(x86_boot_params, real_mode_data, BOOT_PARAM_SIZE);
+	new_data = *(u32 *) (x86_boot_params + NEW_CL_POINTER);
+	if (!new_data) {
+		if (OLD_CL_MAGIC != *(u16 *)(real_mode_data + OLD_CL_MAGIC_ADDR)) {
+			return;
+		}
+		new_data = __pa(real_mode_data) + *(u16 *)(real_mode_data + OLD_CL_OFFSET);
+	}
+	command_line = __va(new_data);
+	memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
+}
+
+void __init x86_64_start_kernel(char * real_mode_data)
+{
+	int i;
+
+	/* clear bss before set_intr_gate with early_idt_handler */
+	clear_bss();
+
+	/* Make NULL pointers segfault */
+	zap_identity_mappings();
+
+	for (i = 0; i < IDT_ENTRIES; i++)
+		set_intr_gate(i, early_idt_handler);
+	asm volatile("lidt %0" :: "m" (idt_descr));
+
+	early_printk("Kernel alive\n");
+
+ 	for (i = 0; i < NR_CPUS; i++)
+ 		cpu_pda(i) = &boot_cpu_pda[i];
+
+	pda_init(0);
+	copy_bootdata(__va(real_mode_data));
+#ifdef CONFIG_SMP
+	cpu_set(0, cpu_online_map);
+#endif
+	start_kernel();
+}