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/*
* linux/arch/arm/boot/bootp/init.S
*
* Copyright (C) 2000 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Header file for splitting kernel + initrd. Note that we pass
* r0 through to r3 straight through.
*/
.section .start,#alloc,#execinstr
.type _entry, #function
_entry: adr r10, initdata
ldr r11, initdata
sub r11, r10, r11 @ work out exec offset
b splitify
.size _entry,. - _entry
.type initdata, #object
initdata: .word initdata @ compiled address of this
.size initdata,. - initdata
.text
splitify: adr r13, data
ldmia r13!, {r4-r6} @ move the initrd
add r4, r4, r11 @ correction
bl move
ldmia r13!, {r4-r6} @ then the kernel
mov r12, r5
add r4, r4, r11 @ correction
bl move
/*
* Setup the initrd parameters to pass to the kernel. This can either be
* passed in via a param_struct or a tag list. We spot the param_struct
* method by looking at the first word; this should either indicate a page
* size of 4K, 16K or 32K.
*/
ldmia r13, {r4-r8} @ get size and addr of initrd
@ r5 = ATAG_INITRD
@ r6 = initrd start
@ r7 = initrd end
@ r8 = param_struct address
ldr r9, [r8, #0] @ no param struct?
teq r9, #0x1000 @ 4K?
teqne r9, #0x4000 @ 16K?
teqne r9, #0x8000 @ 32K?
beq param_struct
ldr r9, [r8, #4] @ get first tag
teq r9, r4
bne taglist @ ok, we have a tag list
/*
* We didn't find a valid tag list - create one.
*/
str r4, [r8, #4]
mov r4, #8
str r4, [r8, #0]
mov r4, #0
str r4, [r8, #8]
/*
* find the end of the tag list, and then add an INITRD tag on the end.
* If there is already an INITRD tag, then we ignore it; the last INITRD
* tag takes precidence.
*/
taglist: ldr r9, [r8, #0] @ tag length
teq r9, #0 @ last tag?
addne r8, r8, r9
bne taglist
mov r4, #16 @ length of initrd tag
mov r9, #0 @ end of tag list terminator
stmia r8, {r4, r5, r6, r7, r9}
mov pc, r12 @ call kernel
/*
* We found a param struct. Modify the param struct for the initrd
*/
param_struct: add r8, r8, #16*4
stmia r8, {r6,r7} @ save in param_struct
mov pc, r12 @ call kernel
move: ldmia r4!, {r7 - r10} @ move 32-bytes at a time
stmia r5!, {r7 - r10}
ldmia r4!, {r7 - r10}
stmia r5!, {r7 - r10}
subs r6, r6, #8 * 4
bcs move
mov pc, lr
data: .word initrd_start
.word initrd_addr
.word initrd_len
.word kernel_start
.word kernel_addr
.word kernel_len
.word 0x54410001 @ r4 = ATAG_CORE
.word 0x54410005 @ r5 = ATAG_INITRD
.word initrd_virt @ r6
.word initrd_len @ r7
.word params @ r8
.type kernel_start,#object
.type initrd_start,#object
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