+/*
+ * linux/arch/x86_64/kernel/head.S -- start in 32bit and switch to 64bit
+ *
+ * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
+ * Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
+ * Copyright (C) 2000 Karsten Keil <kkeil@suse.de>
+ * Copyright (C) 2001,2002 Andi Kleen <ak@suse.de>
+ *
+ * $Id: head.S,v 1.49 2002/03/19 17:39:25 ak Exp $
+ *
+ * Jun Nakajima <jun.nakajima@intel.com>
+ * Modified for Xen
+ */
+
+
+#include <linux/linkage.h>
+#include <linux/threads.h>
+#include <linux/init.h>
+#include <asm/desc.h>
+#include <asm/segment.h>
+#include <asm/page.h>
+#include <asm/msr.h>
+#include <asm/cache.h>
+
+ .text
+ .section .bootstrap.text
+ .code64
+#define VIRT_ENTRY_OFFSET 0x0
+.org VIRT_ENTRY_OFFSET
+ .globl startup_64
+startup_64:
+ENTRY(_start)
+ movq $(init_thread_union+THREAD_SIZE-8),%rsp
+ /* zero EFLAGS after setting rsp */
+ pushq $0
+ popfq
+
+ /* rsi is pointer to startup info structure.
+ pass it to C */
+ movq %rsi,%rdi
+ jmp x86_64_start_kernel
+
+ENTRY(stext)
+ENTRY(_stext)
+
+ $page = 0
+#define NEXT_PAGE(name) \
+ $page = $page + 1; \
+ .org $page * 0x1000; \
+ phys_/**/name = $page * 0x1000 + __PHYSICAL_START; \
+ENTRY(name)
+
+NEXT_PAGE(init_level4_pgt)
+ /* This gets initialized in x86_64_start_kernel */
+ .fill 512,8,0
+
+ /*
+ * We update two pgd entries to make kernel and user pgd consistent
+ * at pgd_populate(). It can be used for kernel modules. So we place
+ * this page here for those cases to avoid memory corruption.
+ * We also use this page to establish the initiali mapping for
+ * vsyscall area.
+ */
+NEXT_PAGE(init_level4_user_pgt)
+ .fill 512,8,0
+
+NEXT_PAGE(level3_kernel_pgt)
+ .fill 512,8,0
+
+ /*
+ * This is used for vsyscall area mapping as we have a different
+ * level4 page table for user.
+ */
+NEXT_PAGE(level3_user_pgt)
+ .fill 512,8,0
+
+NEXT_PAGE(level2_kernel_pgt)
+ .fill 512,8,0
+
+NEXT_PAGE(hypercall_page)
+ .fill 512,8,0
+
+#undef NEXT_PAGE
+
+ .data
+
+ .align 16
+ .globl cpu_gdt_descr
+cpu_gdt_descr:
+ .word gdt_end-cpu_gdt_table-1
+gdt:
+ .quad cpu_gdt_table
+#ifdef CONFIG_SMP
+ .rept NR_CPUS-1
+ .word 0
+ .quad 0
+ .endr
+#endif
+
+/* We need valid kernel segments for data and code in long mode too
+ * IRET will check the segment types kkeil 2000/10/28
+ * Also sysret mandates a special GDT layout
+ */
+
+ .section .data.page_aligned, "aw"
+ .align PAGE_SIZE
+
+/* The TLS descriptors are currently at a different place compared to i386.
+ Hopefully nobody expects them at a fixed place (Wine?) */
+
+ENTRY(cpu_gdt_table)
+ .quad 0x0000000000000000 /* NULL descriptor */
+ .quad 0x0 /* unused */
+ .quad 0x00af9a000000ffff /* __KERNEL_CS */
+ .quad 0x00cf92000000ffff /* __KERNEL_DS */
+ .quad 0x00cffa000000ffff /* __USER32_CS */
+ .quad 0x00cff2000000ffff /* __USER_DS, __USER32_DS */
+ .quad 0x00affa000000ffff /* __USER_CS */
+ .quad 0x00cf9a000000ffff /* __KERNEL32_CS */
+ .quad 0,0 /* TSS */
+ .quad 0,0 /* LDT */
+ .quad 0,0,0 /* three TLS descriptors */
+ .quad 0 /* unused */
+gdt_end:
+ /* asm/segment.h:GDT_ENTRIES must match this */
+ /* This should be a multiple of the cache line size */
+ /* GDTs of other CPUs are now dynamically allocated */
+
+ /* zero the remaining page */
+ .fill PAGE_SIZE / 8 - GDT_ENTRIES,8,0
+
+ .section .bss, "aw", @nobits
+ .align L1_CACHE_BYTES
+ENTRY(idt_table)
+ .skip 256 * 16
+
+ .section .bss.page_aligned, "aw", @nobits
+ .align PAGE_SIZE
+ENTRY(empty_zero_page)
+ .skip PAGE_SIZE
+
+/*
+ * __xen_guest information
+ */
+.macro utoh value
+ .if (\value) < 0 || (\value) >= 0x10
+ utoh (((\value)>>4)&0x0fffffffffffffff)
+ .endif
+ .if ((\value) & 0xf) < 10
+ .byte '0' + ((\value) & 0xf)
+ .else
+ .byte 'A' + ((\value) & 0xf) - 10
+ .endif
+.endm
+
+.section __xen_guest
+ .ascii "GUEST_OS=linux,GUEST_VER=2.6"
+ .ascii ",XEN_VER=xen-3.0"
+ .ascii ",VIRT_BASE=0x"
+ utoh __START_KERNEL_map
+#ifdef CONFIG_XEN_COMPAT_030002
+ .ascii ",ELF_PADDR_OFFSET=0x"
+ utoh __START_KERNEL_map
+#else
+ .ascii ",ELF_PADDR_OFFSET=0x0"
+#endif /* !CONFIG_XEN_COMPAT_030002 */
+ .ascii ",VIRT_ENTRY=0x"
+ utoh (__START_KERNEL_map + __PHYSICAL_START + VIRT_ENTRY_OFFSET)
+ .ascii ",HYPERCALL_PAGE=0x"
+ utoh (phys_hypercall_page >> PAGE_SHIFT)
+ .ascii ",FEATURES=writable_page_tables"
+ .ascii "|writable_descriptor_tables"
+ .ascii "|auto_translated_physmap"
+ .ascii "|supervisor_mode_kernel"
+ .ascii ",LOADER=generic"
+ .byte 0