[mirror_ubuntu-bionic-kernel.git] / arch / powerpc / purgatory / trampoline.S

/*
 * 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
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free
 * Software Foundation (version 2 of the License).
 */

#if defined(__LITTLE_ENDIAN__)
#define STWX_BE	stwbrx
#define LWZX_BE	lwbrx
#elif defined(__BIG_ENDIAN__)
#define STWX_BE	stwx
#define LWZX_BE	lwzx
#else
#error no endianness defined!
#endif

	.machine ppc64
	.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 */

	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 */

	bl	0f		/* Work out where we're running */
0:	mflr	%r18

	/* 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	%r0,%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 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:
	.llong  0x0
	.size kernel, . - kernel

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


	.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
Commit	Line	Data
0d976313 TJB	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	#if defined(__LITTLE_ENDIAN__)
	16	#define STWX_BE stwbrx
	17	#define LWZX_BE lwbrx
	18	#elif defined(__BIG_ENDIAN__)
	19	#define STWX_BE stwx
	20	#define LWZX_BE lwzx
	21	#else
	22	#error no endianness defined!
	23	#endif
	24
	25	.machine ppc64
	26	.balign 256
	27	.globl purgatory_start
	28	purgatory_start:
	29	b master
	30
	31	/* ABI: possible run_at_load flag at 0x5c */
	32	.org purgatory_start + 0x5c
	33	.globl run_at_load
	34	run_at_load:
	35	.long 0
	36	.size run_at_load, . - run_at_load
	37
	38	/* ABI: slaves start at 60 with r3=phys */
	39	.org purgatory_start + 0x60
	40	slave:
	41	b .
	42	/* ABI: end of copied region */
	43	.org purgatory_start + 0x100
	44	.size purgatory_start, . - purgatory_start
	45
	46	/*
	47	* The above 0x100 bytes at purgatory_start are replaced with the
	48	* code from the kernel (or next stage) by setup_purgatory().
	49	*/
	50
	51	master:
	52	or %r1,%r1,%r1 /* low priority to let other threads catchup */
	53	isync
	54	mr %r17,%r3 /* save cpu id to r17 */
	55	mr %r15,%r4 /* save physical address in reg15 */
	56
	57	or %r3,%r3,%r3 /* ok now to high priority, lets boot */
	58	lis %r6,0x1
	59	mtctr %r6 /* delay a bit for slaves to catch up */
	60	bdnz . /* before we overwrite 0-100 again */
	61
	62	bl 0f /* Work out where we're running */
	63	0: mflr %r18
	64
65	/* load device-tree address */
66	ld %r3, (dt_offset - 0b)(%r18)
67	mr %r16,%r3 /* save dt address in reg16 */
68	li %r4,20
69	LWZX_BE %r6,%r3,%r4 /* fetch __be32 version number at byte 20 */
70	cmpwi %r0,%r6,2 /* v2 or later? */
71	blt 1f
72	li %r4,28
73	STWX_BE %r17,%r3,%r4 /* Store my cpu as __be32 at byte 28 */
74	1:
75	/* load the kernel address */
76	ld %r4,(kernel - 0b)(%r18)
77
78	/* load the run_at_load flag */
79	/* possibly patched by kexec */
80	ld %r6,(run_at_load - 0b)(%r18)
81	/* and patch it into the kernel */
82	stw %r6,(0x5c)(%r4)
83
84	mr %r3,%r16 /* restore dt address */
85
86	li %r5,0 /* r5 will be 0 for kernel */
87
88	mfmsr %r11
89	andi. %r10,%r11,1 /* test MSR_LE */
90	bne .Little_endian
91
92	mtctr %r4 /* prepare branch to */
93	bctr /* start kernel */
94
95	.Little_endian:
96	mtsrr0 %r4 /* prepare branch to */
97
98	clrrdi %r11,%r11,1 /* clear MSR_LE */
99	mtsrr1 %r11
100
101	rfid /* update MSR and start kernel */
102
103
104	.balign 8
105	.globl kernel
106	kernel:
107	.llong 0x0
108	.size kernel, . - kernel
109
110	.balign 8
111	.globl dt_offset
112	dt_offset:
113	.llong 0x0
114	.size dt_offset, . - dt_offset
115
116
117	.data
118	.balign 8
40c50c1f TG	119	.globl purgatory_sha256_digest
40c50c1f TG	120	purgatory_sha256_digest:
0d976313	121	.skip 32
40c50c1f	122	.size purgatory_sha256_digest, . - purgatory_sha256_digest
0d976313 TJB	123
0d976313 TJB	124	.balign 8
40c50c1f TG	125	.globl purgatory_sha_regions
40c50c1f TG	126	purgatory_sha_regions:
0d976313	127	.skip 8 * 2 * 16
40c50c1f	128	.size purgatory_sha_regions, . - purgatory_sha_regions