1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * purgatory:  setup code
4 *
5 * Copyright (C) 2003,2004  Eric Biederman (ebiederm@xmission.com)
6 * Copyright (C) 2014 Red Hat Inc.
7 *
8 * This code has been taken from kexec-tools.
9 */
10#include <asm/purgatory.h>
11
12	.text
13	.globl purgatory_start
14	.balign 16
15purgatory_start:
16	.code64
17
18	/* Load a gdt so I know what the segment registers are */
19	lgdt	gdt(%rip)
20
21	/* load the data segments */
22	movl	$0x18, %eax	/* data segment */
23	movl	%eax, %ds
24	movl	%eax, %es
25	movl	%eax, %ss
26	movl	%eax, %fs
27	movl	%eax, %gs
28
29	/* Setup a stack */
30	leaq	lstack_end(%rip), %rsp
31
32	/* Call the C code */
33	call purgatory
34	jmp	entry64
35
36	.section ".rodata"
37	.balign 16
38gdt:	/* 0x00 unusable segment
39	 * 0x08 unused
40	 * so use them as the gdt ptr
41	 */
42	.word	gdt_end - gdt - 1
43	.quad	gdt
44	.word	0, 0, 0
45
46	/* 0x10 4GB flat code segment */
47	.word	0xFFFF, 0x0000, 0x9A00, 0x00AF
48
49	/* 0x18 4GB flat data segment */
50	.word	0xFFFF, 0x0000, 0x9200, 0x00CF
51gdt_end:
52
53	.bss
54	.balign 4096
55lstack:
56	.skip 4096
57lstack_end:
58