1/*
2 * kexec trampoline
3 *
4 * Based on code taken from kexec-tools and kexec-lite.
5 *
6 * Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
7 * Copyright (C) 2006, Mohan Kumar M, IBM Corporation
8 * Copyright (C) 2013, Anton Blanchard, IBM Corporation
9 *
10 * This program is free software; you can redistribute it and/or modify it under
11 * the terms of the GNU General Public License as published by the Free
12 * Software Foundation (version 2 of the License).
13 */
14
15#include <asm/asm-compat.h>
16
17	.machine ppc64
18	.balign 256
19	.globl purgatory_start
20purgatory_start:
21	b	master
22
23	/* ABI: possible run_at_load flag at 0x5c */
24	.org purgatory_start + 0x5c
25	.globl run_at_load
26run_at_load:
27	.long 0
28	.size run_at_load, . - run_at_load
29
30	/* ABI: slaves start at 60 with r3=phys */
31	.org purgatory_start + 0x60
32slave:
33	b .
34	/* ABI: end of copied region */
35	.org purgatory_start + 0x100
36	.size purgatory_start, . - purgatory_start
37
38/*
39 * The above 0x100 bytes at purgatory_start are replaced with the
40 * code from the kernel (or next stage) by setup_purgatory().
41 */
42
43master:
44	or	%r1,%r1,%r1	/* low priority to let other threads catchup */
45	isync
46	mr	%r17,%r3	/* save cpu id to r17 */
47	mr	%r15,%r4	/* save physical address in reg15 */
48
49	or	%r3,%r3,%r3	/* ok now to high priority, lets boot */
50	lis	%r6,0x1
51	mtctr	%r6		/* delay a bit for slaves to catch up */
52	bdnz	.		/* before we overwrite 0-100 again */
53
54	bl	0f		/* Work out where we're running */
550:	mflr	%r18
56
57	/* load device-tree address */
58	ld	%r3, (dt_offset - 0b)(%r18)
59	mr	%r16,%r3	/* save dt address in reg16 */
60	li	%r4,20
61	LWZX_BE	%r6,%r3,%r4	/* fetch __be32 version number at byte 20 */
62	cmpwi	%cr0,%r6,2	/* v2 or later? */
63	blt	1f
64	li	%r4,28
65	STWX_BE	%r17,%r3,%r4	/* Store my cpu as __be32 at byte 28 */
661:
67	/* load the kernel address */
68	ld	%r4,(kernel - 0b)(%r18)
69
70	/* load the run_at_load flag */
71	/* possibly patched by kexec */
72	ld	%r6,(run_at_load - 0b)(%r18)
73	/* and patch it into the kernel */
74	stw	%r6,(0x5c)(%r4)
75
76	mr	%r3,%r16	/* restore dt address */
77
78	li	%r5,0		/* r5 will be 0 for kernel */
79
80	mfmsr	%r11
81	andi.	%r10,%r11,1	/* test MSR_LE */
82	bne	.Little_endian
83
84	mtctr	%r4		/* prepare branch to */
85	bctr			/* start kernel */
86
87.Little_endian:
88	mtsrr0	%r4		/* prepare branch to */
89
90	clrrdi	%r11,%r11,1	/* clear MSR_LE */
91	mtsrr1	%r11
92
93	rfid			/* update MSR and start kernel */
94
95
96	.balign 8
97	.globl kernel
98kernel:
99	.8byte  0x0
100	.size kernel, . - kernel
101
102	.balign 8
103	.globl dt_offset
104dt_offset:
105	.8byte  0x0
106	.size dt_offset, . - dt_offset
107
108
109	.data
110	.balign 8
111.globl purgatory_sha256_digest
112purgatory_sha256_digest:
113	.skip	32
114	.size purgatory_sha256_digest, . - purgatory_sha256_digest
115
116	.balign 8
117.globl purgatory_sha_regions
118purgatory_sha_regions:
119	.skip	8 * 2 * 16
120	.size purgatory_sha_regions, . - purgatory_sha_regions
121