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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 | /* * linux/arch/arm/boot/bootp/init.S * * Copyright (C) 2000-2002 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 _start, #function .globl _start _start: 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 splitify: adr r13, data ldmia r13!, {r4-r6} @ move the initrd 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} adr r12, kernel_start 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 0x54410001 @ r4 = ATAG_CORE .word 0x54420005 @ r5 = ATAG_INITRD .word initrd_addr @ r6 .word initrd_len @ r7 .word params @ r8 .type initrd_start,#object kernel_start: |