1/*
2 * purgatory:  setup code
3 *
4 * Copyright (C) 2003,2004  Eric Biederman (ebiederm@xmission.com)
5 * Copyright (C) 2014 Red Hat Inc.
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#include <asm/purgatory.h>
13
14	.text
15	.globl purgatory_start
16	.balign 16
17purgatory_start:
18	.code64
19
20	/* Load a gdt so I know what the segment registers are */
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 a stack */
32	leaq	lstack_end(%rip), %rsp
33
34	/* Call the C code */
35	call purgatory
36	jmp	entry64
37
38	.section ".rodata"
39	.balign 16
40gdt:	/* 0x00 unusable segment
41	 * 0x08 unused
42	 * so use them as the gdt ptr
43	 */
44	.word	gdt_end - gdt - 1
45	.quad	gdt
46	.word	0, 0, 0
47
48	/* 0x10 4GB flat code segment */
49	.word	0xFFFF, 0x0000, 0x9A00, 0x00AF
50
51	/* 0x18 4GB flat data segment */
52	.word	0xFFFF, 0x0000, 0x9200, 0x00CF
53gdt_end:
54
55	.bss
56	.balign 4096
57lstack:
58	.skip 4096
59lstack_end:
60