summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/purgatory/trampoline_64.S
blob: b35837c138526c5a388589778af91dc142027815 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * kexec trampoline
 *
 * Based on code taken from kexec-tools and kexec-lite.
 *
 * Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
 * Copyright (C) 2006, Mohan Kumar M, IBM Corporation
 * Copyright (C) 2013, Anton Blanchard, IBM Corporation
 */

#include <asm/asm-compat.h>
#include <asm/crashdump-ppc64.h>

	.balign 256
	.globl purgatory_start
purgatory_start:
	b	master

	/* ABI: possible run_at_load flag at 0x5c */
	.org purgatory_start + 0x5c
	.globl run_at_load
run_at_load:
	.long 0
	.size run_at_load, . - run_at_load

	/* ABI: slaves start at 60 with r3=phys */
	.org purgatory_start + 0x60
slave:
	b .
	/* ABI: end of copied region */
	.org purgatory_start + 0x100
	.size purgatory_start, . - purgatory_start

/*
 * The above 0x100 bytes at purgatory_start are replaced with the
 * code from the kernel (or next stage) by setup_purgatory().
 */

master:
	or	%r1,%r1,%r1	/* low priority to let other threads catchup */
	isync
	mr	%r17,%r3	/* save cpu id to r17 */
	mr	%r15,%r4	/* save physical address in reg15 */

	/* Work out where we're running */
	bcl	20, 31, 0f
0:	mflr	%r18

	/*
	 * Copy BACKUP_SRC_SIZE bytes from BACKUP_SRC_START to
	 * backup_start 8 bytes at a time.
	 *
	 * Use r3 = dest, r4 = src, r5 = size, r6 = count
	 */
	ld	%r3, (backup_start - 0b)(%r18)
	cmpdi	%cr0, %r3, 0
	beq	.Lskip_copy	/* skip if there is no backup region */
	lis	%r5, BACKUP_SRC_SIZE@h
	ori	%r5, %r5, BACKUP_SRC_SIZE@l
	cmpdi	%cr0, %r5, 0
	beq	.Lskip_copy	/* skip if copy size is zero */
	lis	%r4, BACKUP_SRC_START@h
	ori	%r4, %r4, BACKUP_SRC_START@l
	li	%r6, 0
.Lcopy_loop:
	ldx	%r0, %r6, %r4
	stdx	%r0, %r6, %r3
	addi	%r6, %r6, 8
	cmpld	%cr0, %r6, %r5
	blt	.Lcopy_loop

.Lskip_copy:
	or	%r3,%r3,%r3	/* ok now to high priority, lets boot */
	lis	%r6,0x1
	mtctr	%r6		/* delay a bit for slaves to catch up */
	bdnz	.		/* before we overwrite 0-100 again */

	/* load device-tree address */
	ld	%r3, (dt_offset - 0b)(%r18)
	mr	%r16,%r3	/* save dt address in reg16 */
	li	%r4,20
	LWZX_BE	%r6,%r3,%r4	/* fetch __be32 version number at byte 20 */
	cmpwi	%cr0,%r6,2	/* v2 or later? */
	blt	1f
	li	%r4,28
	STWX_BE	%r17,%r3,%r4	/* Store my cpu as __be32 at byte 28 */
1:
	/* Load opal base and entry values in r8 & r9 respectively */
	ld	%r8,(opal_base - 0b)(%r18)
	ld	%r9,(opal_entry - 0b)(%r18)

	/* load the kernel address */
	ld	%r4,(kernel - 0b)(%r18)

	/* load the run_at_load flag */
	/* possibly patched by kexec */
	ld	%r6,(run_at_load - 0b)(%r18)
	/* and patch it into the kernel */
	stw	%r6,(0x5c)(%r4)

	mr	%r3,%r16	/* restore dt address */

	li	%r5,0		/* r5 will be 0 for kernel */

	mfmsr	%r11
	andi.	%r10,%r11,1	/* test MSR_LE */
	bne	.Little_endian

	mtctr	%r4		/* prepare branch to */
	bctr			/* start kernel */

.Little_endian:
	mtsrr0	%r4		/* prepare branch to */

	clrrdi	%r11,%r11,1	/* clear MSR_LE */
	mtsrr1	%r11

	rfid			/* update MSR and start kernel */

	.balign 8
	.globl kernel
kernel:
	.8byte  0x0
	.size kernel, . - kernel

	.balign 8
	.globl dt_offset
dt_offset:
	.8byte  0x0
	.size dt_offset, . - dt_offset

	.balign 8
	.globl backup_start
backup_start:
	.8byte  0x0
	.size backup_start, . - backup_start

	.balign 8
	.globl opal_base
opal_base:
	.8byte  0x0
	.size opal_base, . - opal_base

	.balign 8
	.globl opal_entry
opal_entry:
	.8byte  0x0
	.size opal_entry, . - opal_entry

	.data
	.balign 8
.globl purgatory_sha256_digest
purgatory_sha256_digest:
	.skip	32
	.size purgatory_sha256_digest, . - purgatory_sha256_digest

	.balign 8
.globl purgatory_sha_regions
purgatory_sha_regions:
	.skip	8 * 2 * 16
	.size purgatory_sha_regions, . - purgatory_sha_regions