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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/sh/kernel/relocate_kernel.S
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/* SPDX-License-Identifier: GPL-2.0

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 *

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 * relocate_kernel.S - put the kernel image in place to boot

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 * 2005.9.17 [email protected]

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 *

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 * LANDISK/sh4 is supported. Maybe, SH archtecture works well.

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 *

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 * 2009-03-18 Magnus Damm - Added Kexec Jump support

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 */

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#include <linux/linkage.h>

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#include <asm/addrspace.h>

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#include <asm/page.h>

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		.globl relocate_new_kernel

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relocate_new_kernel:

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	/* r4 = indirection_page   */

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	/* r5 = reboot_code_buffer */

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	/* r6 = start_address      */

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	mov.l	10f, r0		/* PAGE_SIZE */

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	add	r5, r0		/* setup new stack at end of control page */

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	/* save r15->r8 to new stack */

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	mov.l	r15, @-r0

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	mov	r0, r15

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	mov.l	r14, @-r15

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	mov.l	r13, @-r15

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	mov.l	r12, @-r15

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	mov.l	r11, @-r15

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	mov.l	r10, @-r15

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	mov.l	r9, @-r15

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	mov.l	r8, @-r15

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	/* save other random registers */

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	sts.l	macl, @-r15

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	sts.l	mach, @-r15

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	stc.l	gbr, @-r15

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	stc.l	ssr, @-r15

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	stc.l	sr, @-r15

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	sts.l	pr, @-r15

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	stc.l	spc, @-r15

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	/* switch to bank1 and save r7->r0 */

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	mov.l	12f, r9

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	stc	sr, r8

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	or	r9, r8

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	ldc	r8, sr

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	mov.l	r7, @-r15

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	mov.l	r6, @-r15

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	mov.l	r5, @-r15

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	mov.l	r4, @-r15

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	mov.l	r3, @-r15

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	mov.l	r2, @-r15

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	mov.l	r1, @-r15

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	mov.l	r0, @-r15

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	/* switch to bank0 and save r7->r0 */

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	mov.l	12f, r9

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	not	r9, r9

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	stc	sr, r8

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	and	r9, r8

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	ldc	r8, sr

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	mov.l	r7, @-r15

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	mov.l	r6, @-r15

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	mov.l	r5, @-r15

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	mov.l	r4, @-r15

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	mov.l	r3, @-r15

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	mov.l	r2, @-r15

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	mov.l	r1, @-r15

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	mov.l	r0, @-r15

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

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

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	 nop

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	mova	11f, r0

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

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

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	 nop

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	mov.l	11f, r15	/* get pointer to stack */

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	mov.l	@r15+, r4	/* restore r4 to get indirection page */

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

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	 nop

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	/* make sure bank0 is active and restore r0->r7 */

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	mov.l	12f, r9

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	not	r9, r9

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	stc	sr, r8

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	and	r9, r8

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	ldc	r8, sr

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	mov.l	@r15+, r0

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	mov.l	@r15+, r1

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	mov.l	@r15+, r2

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	mov.l	@r15+, r3

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	mov.l	@r15+, r4

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	mov.l	@r15+, r5

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	mov.l	@r15+, r6

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	mov.l	@r15+, r7

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	/* switch to bank1 and restore r0->r7 */

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	mov.l	12f, r9

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	stc	sr, r8

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	or	r9, r8

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	ldc	r8, sr

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	mov.l	@r15+, r0

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	mov.l	@r15+, r1

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	mov.l	@r15+, r2

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	mov.l	@r15+, r3

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	mov.l	@r15+, r4

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	mov.l	@r15+, r5

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	mov.l	@r15+, r6

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	mov.l	@r15+, r7

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	/* switch back to bank0 */

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	mov.l	12f, r9

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	not	r9, r9

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	stc	sr, r8

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	and	r9, r8

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	ldc	r8, sr

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	/* restore other random registers */

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	ldc.l	@r15+, spc

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	lds.l	@r15+, pr

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	ldc.l	@r15+, sr

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	ldc.l	@r15+, ssr

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	ldc.l	@r15+, gbr

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	lds.l	@r15+, mach

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	lds.l	@r15+, macl

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	/* restore r8->r15 */

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	mov.l	@r15+, r8

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	mov.l	@r15+, r9

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	mov.l	@r15+, r10

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	mov.l	@r15+, r11

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	mov.l	@r15+, r12

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	mov.l	@r15+, r13

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	mov.l	@r15+, r14

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	mov.l	@r15+, r15

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	rts

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	 nop

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swap_pages:

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	bra	1f

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	 mov	r4,r0	  /* cmd = indirection_page */

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0:

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	mov.l	@r4+,r0	  /* cmd = *ind++ */

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1:	/* addr = cmd & 0xfffffff0 */

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	mov	r0,r2

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	mov	#-16,r1

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	and	r1,r2

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	/* if(cmd & IND_DESTINATION) dst = addr  */

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	tst	#1,r0

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	bt	2f

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	bra	0b

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	 mov	r2,r5

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2:	/* else if(cmd & IND_INDIRECTION) ind = addr  */

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	tst	#2,r0

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	bt	3f

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	bra	0b

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	 mov	r2,r4

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3:	/* else if(cmd & IND_DONE) return */

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	tst	#4,r0

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	bt	4f

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	rts

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	 nop

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4:	/* else if(cmd & IND_SOURCE) memcpy(dst,addr,PAGE_SIZE) */

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	tst	#8,r0

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	bt	0b

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	mov.l	10f,r3	  /* PAGE_SIZE */

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	shlr2	r3

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	shlr2	r3

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5:

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	dt	r3

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	/* regular kexec just overwrites the destination page

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	 * with the contents of the source page.

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	 * for the kexec jump case we need to swap the contents

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	 * of the pages.

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	 * to keep it simple swap the contents for both cases.

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	 */

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	mov.l	@(0, r2), r8

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	mov.l	@(0, r5), r1

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	mov.l	r8, @(0, r5)

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	mov.l	r1, @(0, r2)

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	mov.l	@(4, r2), r8

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	mov.l	@(4, r5), r1

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	mov.l	r8, @(4, r5)

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	mov.l	r1, @(4, r2)

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	mov.l	@(8, r2), r8

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	mov.l	@(8, r5), r1

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	mov.l	r8, @(8, r5)

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	mov.l	r1, @(8, r2)

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	mov.l	@(12, r2), r8

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	mov.l	@(12, r5), r1

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	mov.l	r8, @(12, r5)

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	mov.l	r1, @(12, r2)

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	add	#16,r5

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	add	#16,r2

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	bf	5b

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	bra	0b

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	 nop

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	.align 2

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10:

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	.long	PAGE_SIZE

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11:

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	.long	0

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12:

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	.long	0x20000000 ! RB=1

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relocate_new_kernel_end:

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	.globl relocate_new_kernel_size

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relocate_new_kernel_size:

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	.long relocate_new_kernel_end - relocate_new_kernel

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