xref: /linux/arch/powerpc/boot/crt0.S (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1/*
2 * Copyright (C) Paul Mackerras 1997.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 * NOTE: this code runs in 32 bit mode and is packaged as ELF32.
10 */
11
12#include "ppc_asm.h"
13
14	.text
15	/* a procedure descriptor used when booting this as a COFF file */
16_zimage_start_opd:
17	.long	_zimage_start, 0, 0, 0
18
19	.globl	_zimage_start
20_zimage_start:
21	/* Work out the offset between the address we were linked at
22	   and the address where we're running. */
23	bl	1f
241:	mflr	r0
25	lis	r9,1b@ha
26	addi	r9,r9,1b@l
27	subf.	r0,r9,r0
28	beq	3f		/* if running at same address as linked */
29
30	/* The .got2 section contains a list of addresses, so add
31	   the address offset onto each entry. */
32	lis	r9,__got2_start@ha
33	addi	r9,r9,__got2_start@l
34	lis	r8,__got2_end@ha
35	addi	r8,r8,__got2_end@l
36	subf.	r8,r9,r8
37	beq	3f
38	srwi.	r8,r8,2
39	mtctr	r8
40	add	r9,r0,r9
412:	lwz	r8,0(r9)
42	add	r8,r8,r0
43	stw	r8,0(r9)
44	addi	r9,r9,4
45	bdnz	2b
46
47	/* Do a cache flush for our text, in case OF didn't */
483:	lis	r9,_start@ha
49	addi	r9,r9,_start@l
50	add	r9,r0,r9
51	lis	r8,_etext@ha
52	addi	r8,r8,_etext@l
53	add	r8,r0,r8
544:	dcbf	r0,r9
55	icbi	r0,r9
56	addi	r9,r9,0x20
57	cmplw	cr0,r9,r8
58	blt	4b
59	sync
60	isync
61
62	mr	r6,r1
63	b	start
64
65