1/*
  2 * Copyright (C) 2003,2004  Eric Biederman (ebiederm@xmission.com)
  3 * Copyright (C) 2014  Red Hat Inc.
  4
  5 * Author(s): Vivek Goyal <vgoyal@redhat.com>
  6 *
  7 * This code has been taken from kexec-tools.
  8 *
  9 * This source code is licensed under the GNU General Public License,
 10 * Version 2.  See the file COPYING for more details.
 11 */
 12
 13	.text
 14	.balign 16
 15	.code64
 16	.globl entry64, entry64_regs
 17
 18
 19entry64:
 20	/* Setup a gdt that should be preserved */
 21	lgdt gdt(%rip)
 22
 23	/* load the data segments */
 24	movl    $0x18, %eax     /* data segment */
 25	movl    %eax, %ds
 26	movl    %eax, %es
 27	movl    %eax, %ss
 28	movl    %eax, %fs
 29	movl    %eax, %gs
 30
 31	/* Setup new stack */
 32	leaq    stack_init(%rip), %rsp
 33	pushq   $0x10 /* CS */
 34	leaq    new_cs_exit(%rip), %rax
 35	pushq   %rax
 36	lretq
 37new_cs_exit:
 38
 39	/* Load the registers */
 40	movq	rax(%rip), %rax
 41	movq	rbx(%rip), %rbx
 42	movq	rcx(%rip), %rcx
 43	movq	rdx(%rip), %rdx
 44	movq	rsi(%rip), %rsi
 45	movq	rdi(%rip), %rdi
 46	movq    rsp(%rip), %rsp
 47	movq	rbp(%rip), %rbp
 48	movq	r8(%rip), %r8
 49	movq	r9(%rip), %r9
 50	movq	r10(%rip), %r10
 51	movq	r11(%rip), %r11
 52	movq	r12(%rip), %r12
 53	movq	r13(%rip), %r13
 54	movq	r14(%rip), %r14
 55	movq	r15(%rip), %r15
 56
 57	/* Jump to the new code... */
 58	jmpq	*rip(%rip)
 59
 60	.section ".rodata"
 61	.balign 4
 62entry64_regs:
 63rax:	.quad 0x0
 64rcx:	.quad 0x0
 65rdx:	.quad 0x0
 66rbx:	.quad 0x0
 67rsp:	.quad 0x0
 68rbp:	.quad 0x0
 69rsi:	.quad 0x0
 70rdi:	.quad 0x0
 71r8:	.quad 0x0
 72r9:	.quad 0x0
 73r10:	.quad 0x0
 74r11:	.quad 0x0
 75r12:	.quad 0x0
 76r13:	.quad 0x0
 77r14:	.quad 0x0
 78r15:	.quad 0x0
 79rip:	.quad 0x0
 80	.size entry64_regs, . - entry64_regs
 81
 82	/* GDT */
 83	.section ".rodata"
 84	.balign 16
 85gdt:
 86	/* 0x00 unusable segment
 87	 * 0x08 unused
 88	 * so use them as gdt ptr
 89	 */
 90	.word gdt_end - gdt - 1
 91	.quad gdt
 92	.word 0, 0, 0
 93
 94	/* 0x10 4GB flat code segment */
 95	.word 0xFFFF, 0x0000, 0x9A00, 0x00AF
 96
 97	/* 0x18 4GB flat data segment */
 98	.word 0xFFFF, 0x0000, 0x9200, 0x00CF
 99gdt_end:
100stack:	.quad   0, 0
101stack_init: