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
14	.machine ppc64
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	or	%r3,%r3,%r3	/* ok now to high priority, lets boot */
47	lis	%r6,0x1
48	mtctr	%r6		/* delay a bit for slaves to catch up */
49	bdnz	.		/* before we overwrite 0-100 again */
50
51	bl	0f		/* Work out where we're running */
520:	mflr	%r18
53
54	/* load device-tree address */
55	ld	%r3, (dt_offset - 0b)(%r18)
56	mr	%r16,%r3	/* save dt address in reg16 */
57	li	%r4,20
58	LWZX_BE	%r6,%r3,%r4	/* fetch __be32 version number at byte 20 */
59	cmpwi	%cr0,%r6,2	/* v2 or later? */
60	blt	1f
61	li	%r4,28
62	STWX_BE	%r17,%r3,%r4	/* Store my cpu as __be32 at byte 28 */
631:
64	/* load the kernel address */
65	ld	%r4,(kernel - 0b)(%r18)
66
67	/* load the run_at_load flag */
68	/* possibly patched by kexec */
69	ld	%r6,(run_at_load - 0b)(%r18)
70	/* and patch it into the kernel */
71	stw	%r6,(0x5c)(%r4)
72
73	mr	%r3,%r16	/* restore dt address */
74
75	li	%r5,0		/* r5 will be 0 for kernel */
76
77	mfmsr	%r11
78	andi.	%r10,%r11,1	/* test MSR_LE */
79	bne	.Little_endian
80
81	mtctr	%r4		/* prepare branch to */
82	bctr			/* start kernel */
83
84.Little_endian:
85	mtsrr0	%r4		/* prepare branch to */
86
87	clrrdi	%r11,%r11,1	/* clear MSR_LE */
88	mtsrr1	%r11
89
90	rfid			/* update MSR and start kernel */
91
92
93	.balign 8
94	.globl kernel
95kernel:
96	.8byte  0x0
97	.size kernel, . - kernel
98
99	.balign 8
100	.globl dt_offset
101dt_offset:
102	.8byte  0x0
103	.size dt_offset, . - dt_offset
104
105
106	.data
107	.balign 8
108.globl purgatory_sha256_digest
109purgatory_sha256_digest:
110	.skip	32
111	.size purgatory_sha256_digest, . - purgatory_sha256_digest
112
113	.balign 8
114.globl purgatory_sha_regions
115purgatory_sha_regions:
116	.skip	8 * 2 * 16
117	.size purgatory_sha_regions, . - purgatory_sha_regions
118