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:
102