x86_64: move kernel

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 166 insertions, 0 deletions

diff --git a/arch/x86/kernel/trampoline_64.S b/arch/x86/kernel/trampoline_64.S
new file mode 100644
index 000000000000..607983b0d27b
--- /dev/null
+++ b/arch/x86/kernel/trampoline_64.S
@@ -0,0 +1,166 @@
+/*
+ *
+ *	Trampoline.S	Derived from Setup.S by Linus Torvalds
+ *
+ *	4 Jan 1997 Michael Chastain: changed to gnu as.
+ *	15 Sept 2005 Eric Biederman: 64bit PIC support
+ *
+ *	Entry: CS:IP point to the start of our code, we are 
+ *	in real mode with no stack, but the rest of the 
+ *	trampoline page to make our stack and everything else
+ *	is a mystery.
+ *
+ *	In fact we don't actually need a stack so we don't
+ *	set one up.
+ *
+ *	On entry to trampoline_data, the processor is in real mode
+ *	with 16-bit addressing and 16-bit data.  CS has some value
+ *	and IP is zero.  Thus, data addresses need to be absolute
+ *	(no relocation) and are taken with regard to r_base.
+ *
+ *	With the addition of trampoline_level4_pgt this code can
+ *	now enter a 64bit kernel that lives at arbitrary 64bit
+ *	physical addresses.
+ *
+ *	If you work on this file, check the object module with objdump
+ *	--full-contents --reloc to make sure there are no relocation
+ *	entries.
+ */
+
+#include <linux/linkage.h>
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <asm/msr.h>
+#include <asm/segment.h>
+
+.data
+
+.code16
+
+ENTRY(trampoline_data)
+r_base = .
+	cli			# We should be safe anyway
+	wbinvd	
+	mov	%cs, %ax	# Code and data in the same place
+	mov	%ax, %ds
+	mov	%ax, %es
+	mov	%ax, %ss
+
+
+	movl	$0xA5A5A5A5, trampoline_data - r_base
+				# write marker for master knows we're running
+
+					# Setup stack
+	movw	$(trampoline_stack_end - r_base), %sp
+
+	call	verify_cpu		# Verify the cpu supports long mode
+	testl   %eax, %eax		# Check for return code
+	jnz	no_longmode
+
+	mov	%cs, %ax
+	movzx	%ax, %esi		# Find the 32bit trampoline location
+	shll	$4, %esi
+
+					# Fixup the vectors
+	addl	%esi, startup_32_vector - r_base
+	addl	%esi, startup_64_vector - r_base
+	addl	%esi, tgdt + 2 - r_base	# Fixup the gdt pointer
+
+	/*
+	 * GDT tables in non default location kernel can be beyond 16MB and
+	 * lgdt will not be able to load the address as in real mode default
+	 * operand size is 16bit. Use lgdtl instead to force operand size
+	 * to 32 bit.
+	 */
+
+	lidtl	tidt - r_base	# load idt with 0, 0
+	lgdtl	tgdt - r_base	# load gdt with whatever is appropriate
+
+	xor	%ax, %ax
+	inc	%ax		# protected mode (PE) bit
+	lmsw	%ax		# into protected mode
+
+	# flush prefetch and jump to startup_32
+	ljmpl	*(startup_32_vector - r_base)
+
+	.code32
+	.balign 4
+startup_32:
+	movl	$__KERNEL_DS, %eax	# Initialize the %ds segment register
+	movl	%eax, %ds
+
+	xorl	%eax, %eax
+	btsl	$5, %eax		# Enable PAE mode
+	movl	%eax, %cr4
+
+					# Setup trampoline 4 level pagetables
+	leal	(trampoline_level4_pgt - r_base)(%esi), %eax
+	movl	%eax, %cr3
+
+	movl	$MSR_EFER, %ecx
+	movl	$(1 << _EFER_LME), %eax	# Enable Long Mode
+	xorl	%edx, %edx
+	wrmsr
+
+	xorl	%eax, %eax
+	btsl	$31, %eax		# Enable paging and in turn activate Long Mode
+	btsl	$0, %eax		# Enable protected mode
+	movl	%eax, %cr0
+
+	/*
+	 * At this point we're in long mode but in 32bit compatibility mode
+	 * with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn
+	 * EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use
+	 * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
+	 */
+	ljmp	*(startup_64_vector - r_base)(%esi)
+
+	.code64
+	.balign 4
+startup_64:
+	# Now jump into the kernel using virtual addresses
+	movq	$secondary_startup_64, %rax
+	jmp	*%rax
+
+	.code16
+no_longmode:
+	hlt
+	jmp no_longmode
+#include "verify_cpu_64.S"
+
+	# Careful these need to be in the same 64K segment as the above;
+tidt:
+	.word	0			# idt limit = 0
+	.word	0, 0			# idt base = 0L
+
+	# Duplicate the global descriptor table
+	# so the kernel can live anywhere
+	.balign 4
+tgdt:
+	.short	tgdt_end - tgdt		# gdt limit
+	.long	tgdt - r_base
+	.short 0
+	.quad	0x00cf9b000000ffff	# __KERNEL32_CS
+	.quad	0x00af9b000000ffff	# __KERNEL_CS
+	.quad	0x00cf93000000ffff	# __KERNEL_DS
+tgdt_end:
+
+	.balign 4
+startup_32_vector:
+	.long	startup_32 - r_base
+	.word	__KERNEL32_CS, 0
+
+	.balign 4
+startup_64_vector:
+	.long	startup_64 - r_base
+	.word	__KERNEL_CS, 0
+
+trampoline_stack:
+	.org 0x1000
+trampoline_stack_end:
+ENTRY(trampoline_level4_pgt)
+	.quad	level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
+	.fill	510,8,0
+	.quad	level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
+
+ENTRY(trampoline_end)