1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * kexec trampoline
4 *
5 * Based on code taken from kexec-tools and kexec-lite.
6 *
7 * Copyright (C) 2004 - 2005, Milton D Miller II, IBM Corporation
8 * Copyright (C) 2006, Mohan Kumar M, IBM Corporation
9 * Copyright (C) 2013, Anton Blanchard, IBM Corporation
10 */
11
12#include <asm/asm-compat.h>
13#include <asm/crashdump-ppc64.h>
14
15 .balign 256
16 .globl purgatory_start
17purgatory_start:
18 b master
19
20 /* ABI: possible run_at_load flag at 0x5c */
21 .org purgatory_start + 0x5c
22 .globl run_at_load
23run_at_load:
24 .long 0
25 .size run_at_load, . - run_at_load
26
27 /* ABI: slaves start at 60 with r3=phys */
28 .org purgatory_start + 0x60
29slave:
30 b .
31 /* ABI: end of copied region */
32 .org purgatory_start + 0x100
33 .size purgatory_start, . - purgatory_start
34
35/*
36 * The above 0x100 bytes at purgatory_start are replaced with the
37 * code from the kernel (or next stage) by setup_purgatory().
38 */
39
40master:
41 or %r1,%r1,%r1 /* low priority to let other threads catchup */
42 isync
43 mr %r17,%r3 /* save cpu id to r17 */
44 mr %r15,%r4 /* save physical address in reg15 */
45
46 /* Work out where we're running */
47 bcl 20, 31, 0f
480: mflr %r18
49
50 /*
51 * Copy BACKUP_SRC_SIZE bytes from BACKUP_SRC_START to
52 * backup_start 8 bytes at a time.
53 *
54 * Use r3 = dest, r4 = src, r5 = size, r6 = count
55 */
56 ld %r3, (backup_start - 0b)(%r18)
57 cmpdi %cr0, %r3, 0
58 beq .Lskip_copy /* skip if there is no backup region */
59 lis %r5, BACKUP_SRC_SIZE@h
60 ori %r5, %r5, BACKUP_SRC_SIZE@l
61 cmpdi %cr0, %r5, 0
62 beq .Lskip_copy /* skip if copy size is zero */
63 lis %r4, BACKUP_SRC_START@h
64 ori %r4, %r4, BACKUP_SRC_START@l
65 li %r6, 0
66.Lcopy_loop:
67 ldx %r0, %r6, %r4
68 stdx %r0, %r6, %r3
69 addi %r6, %r6, 8
70 cmpld %cr0, %r6, %r5
71 blt .Lcopy_loop
72
73.Lskip_copy:
74 or %r3,%r3,%r3 /* ok now to high priority, lets boot */
75 lis %r6,0x1
76 mtctr %r6 /* delay a bit for slaves to catch up */
77 bdnz . /* before we overwrite 0-100 again */
78
79 /* load device-tree address */
80 ld %r3, (dt_offset - 0b)(%r18)
81 mr %r16,%r3 /* save dt address in reg16 */
82 li %r4,20
83 LWZX_BE %r6,%r3,%r4 /* fetch __be32 version number at byte 20 */
84 cmpwi %cr0,%r6,2 /* v2 or later? */
85 blt 1f
86 li %r4,28
87 STWX_BE %r17,%r3,%r4 /* Store my cpu as __be32 at byte 28 */
881:
89 /* Load opal base and entry values in r8 & r9 respectively */
90 ld %r8,(opal_base - 0b)(%r18)
91 ld %r9,(opal_entry - 0b)(%r18)
92
93 /* load the kernel address */
94 ld %r4,(kernel - 0b)(%r18)
95
96 /* load the run_at_load flag */
97 /* possibly patched by kexec */
98 ld %r6,(run_at_load - 0b)(%r18)
99 /* and patch it into the kernel */
100 stw %r6,(0x5c)(%r4)
101
102 mr %r3,%r16 /* restore dt address */
103
104 li %r5,0 /* r5 will be 0 for kernel */
105
106 mfmsr %r11
107 andi. %r10,%r11,1 /* test MSR_LE */
108 bne .Little_endian
109
110 mtctr %r4 /* prepare branch to */
111 bctr /* start kernel */
112
113.Little_endian:
114 mtsrr0 %r4 /* prepare branch to */
115
116 clrrdi %r11,%r11,1 /* clear MSR_LE */
117 mtsrr1 %r11
118
119 rfid /* update MSR and start kernel */
120
121 .balign 8
122 .globl kernel
123kernel:
124 .8byte 0x0
125 .size kernel, . - kernel
126
127 .balign 8
128 .globl dt_offset
129dt_offset:
130 .8byte 0x0
131 .size dt_offset, . - dt_offset
132
133 .balign 8
134 .globl backup_start
135backup_start:
136 .8byte 0x0
137 .size backup_start, . - backup_start
138
139 .balign 8
140 .globl opal_base
141opal_base:
142 .8byte 0x0
143 .size opal_base, . - opal_base
144
145 .balign 8
146 .globl opal_entry
147opal_entry:
148 .8byte 0x0
149 .size opal_entry, . - opal_entry
150
151 .data
152 .balign 8
153.globl purgatory_sha256_digest
154purgatory_sha256_digest:
155 .skip 32
156 .size purgatory_sha256_digest, . - purgatory_sha256_digest
157
158 .balign 8
159.globl purgatory_sha_regions
160purgatory_sha_regions:
161 .skip 8 * 2 * 16
162 .size purgatory_sha_regions, . - purgatory_sha_regions
163

source code of linux/arch/powerpc/purgatory/trampoline_64.S