aboutsummaryrefslogtreecommitdiffstats
path: root/arch/sh/kernel/relocate_kernel.S
blob: fcc9934fb97b8fd24932ee034f88a1c1042fd1f4 (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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
/*
 * relocate_kernel.S - put the kernel image in place to boot
 * 2005.9.17 kogiidena@eggplant.ddo.jp
 *
 * LANDISK/sh4 is supported. Maybe, SH archtecture works well.
 *
 * 2009-03-18 Magnus Damm - Added Kexec Jump support
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */
#include <linux/linkage.h>
#include <asm/addrspace.h>
#include <asm/page.h>

		.globl relocate_new_kernel
relocate_new_kernel:
	/* r4 = indirection_page   */
	/* r5 = reboot_code_buffer */
	/* r6 = start_address      */

	mov.l	10f, r0		/* PAGE_SIZE */
	add	r5, r0		/* setup new stack at end of control page */

	/* save r15->r8 to new stack */
	mov.l	r15, @-r0
	mov	r0, r15
	mov.l	r14, @-r15
	mov.l	r13, @-r15
	mov.l	r12, @-r15
	mov.l	r11, @-r15
	mov.l	r10, @-r15
	mov.l	r9, @-r15
	mov.l	r8, @-r15

	/* save other random registers */
	sts.l	macl, @-r15
	sts.l	mach, @-r15
	stc.l	gbr, @-r15
	stc.l	ssr, @-r15
	stc.l	sr, @-r15
	sts.l	pr, @-r15
	stc.l	spc, @-r15

	/* switch to bank1 and save r7->r0 */
	mov.l	12f, r9
	stc	sr, r8
	or	r9, r8
	ldc	r8, sr
	mov.l	r7, @-r15
	mov.l	r6, @-r15
	mov.l	r5, @-r15
	mov.l	r4, @-r15
	mov.l	r3, @-r15
	mov.l	r2, @-r15
	mov.l	r1, @-r15
	mov.l	r0, @-r15

	/* switch to bank0 and save r7->r0 */
	mov.l	12f, r9
	not	r9, r9
	stc	sr, r8
	and	r9, r8
	ldc	r8, sr
	mov.l	r7, @-r15
	mov.l	r6, @-r15
	mov.l	r5, @-r15
	mov.l	r4, @-r15
	mov.l	r3, @-r15
	mov.l	r2, @-r15
	mov.l	r1, @-r15
	mov.l	r0, @-r15

	mov.l	r4, @-r15	/* save indirection page again */

	bsr	swap_pages	/* swap pages before jumping to new kernel */
	 nop

	mova	11f, r0
	mov.l	r15, @r0	/* save pointer to stack */

	jsr	@r6		/* hand over control to new kernel */
	 nop

	mov.l	11f, r15	/* get pointer to stack */
	mov.l	@r15+, r4	/* restore r4 to get indirection page */

	bsr	swap_pages	/* swap pages back to previous state */
	 nop

	/* make sure bank0 is active and restore r0->r7 */
	mov.l	12f, r9
	not	r9, r9
	stc	sr, r8
	and	r9, r8
	ldc	r8, sr
	mov.l	@r15+, r0
	mov.l	@r15+, r1
	mov.l	@r15+, r2
	mov.l	@r15+, r3
	mov.l	@r15+, r4
	mov.l	@r15+, r5
	mov.l	@r15+, r6
	mov.l	@r15+, r7

	/* switch to bank1 and restore r0->r7 */
	mov.l	12f, r9
	stc	sr, r8
	or	r9, r8
	ldc	r8, sr
	mov.l	@r15+, r0
	mov.l	@r15+, r1
	mov.l	@r15+, r2
	mov.l	@r15+, r3
	mov.l	@r15+, r4
	mov.l	@r15+, r5
	mov.l	@r15+, r6
	mov.l	@r15+, r7

	/* switch back to bank0 */
	mov.l	12f, r9
	not	r9, r9
	stc	sr, r8
	and	r9, r8
	ldc	r8, sr

	/* restore other random registers */
	ldc.l	@r15+, spc
	lds.l	@r15+, pr
	ldc.l	@r15+, sr
	ldc.l	@r15+, ssr
	ldc.l	@r15+, gbr
	lds.l	@r15+, mach
	lds.l	@r15+, macl

	/* restore r8->r15 */
	mov.l	@r15+, r8
	mov.l	@r15+, r9
	mov.l	@r15+, r10
	mov.l	@r15+, r11
	mov.l	@r15+, r12
	mov.l	@r15+, r13
	mov.l	@r15+, r14
	mov.l	@r15+, r15
	rts
	 nop

swap_pages:
	bra	1f
	 mov	r4,r0	  /* cmd = indirection_page */
0:
	mov.l	@r4+,r0	  /* cmd = *ind++ */

1:	/* addr = cmd & 0xfffffff0 */
	mov	r0,r2
	mov	#-16,r1
	and	r1,r2

	/* if(cmd & IND_DESTINATION) dst = addr  */
	tst	#1,r0
	bt	2f
	bra	0b
	 mov	r2,r5

2:	/* else if(cmd & IND_INDIRECTION) ind = addr  */
	tst	#2,r0
	bt	3f
	bra	0b
	 mov	r2,r4

3:	/* else if(cmd & IND_DONE) return */
	tst	#4,r0
	bt	4f
	rts
	 nop

4:	/* else if(cmd & IND_SOURCE) memcpy(dst,addr,PAGE_SIZE) */
	tst	#8,r0
	bt	0b

	mov.l	10f,r3	  /* PAGE_SIZE */
	shlr2	r3
	shlr2	r3
5:
	dt	r3

	/* regular kexec just overwrites the destination page
	 * with the contents of the source page.
	 * for the kexec jump case we need to swap the contents
	 * of the pages.
	 * to keep it simple swap the contents for both cases.
	 */
	mov.l	@(0, r2), r8
	mov.l	@(0, r5), r1
	mov.l	r8, @(0, r5)
	mov.l	r1, @(0, r2)

	mov.l	@(4, r2), r8
	mov.l	@(4, r5), r1
	mov.l	r8, @(4, r5)
	mov.l	r1, @(4, r2)

	mov.l	@(8, r2), r8
	mov.l	@(8, r5), r1
	mov.l	r8, @(8, r5)
	mov.l	r1, @(8, r2)

	mov.l	@(12, r2), r8
	mov.l	@(12, r5), r1
	mov.l	r8, @(12, r5)
	mov.l	r1, @(12, r2)

	add	#16,r5
	add	#16,r2
	bf	5b

	bra	0b
	 nop

	.align 2
10:
	.long	PAGE_SIZE
11:
	.long	0
12:
	.long	0x20000000 ! RB=1

relocate_new_kernel_end:

	.globl relocate_new_kernel_size
relocate_new_kernel_size:
	.long relocate_new_kernel_end - relocate_new_kernel