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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/boot/bootp/init.S
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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diff --git a/arch/arm/boot/bootp/init.S b/arch/arm/boot/bootp/init.S
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+/*
+ * linux/arch/arm/boot/bootp/init.S
+ *
+ * Copyright (C) 2000-2003 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.
+ *
+ * This demonstrates how to append code to the start of the kernel
+ * zImage, and boot the kernel without copying it around. This
+ * example would be simpler; if we didn't have an object of unknown
+ * size immediately following the kernel, we could build this into
+ * a binary blob, and concatenate the zImage using the cat command.
+ */
+ .section .start,#alloc,#execinstr
+ .type _start, #function
+ .globl _start
+
+_start: add lr, pc, #-0x8 @ lr = current load addr
+ adr r13, data
+ ldmia r13!, {r4-r6} @ r5 = dest, r6 = length
+ add r4, r4, lr @ r4 = initrd_start + load addr
+ bl move @ move the initrd
+
+/*
+ * Setup the initrd parameters to pass to the kernel. This can only be
+ * passed in via the tagged list.
+ */
+ ldmia r13, {r5-r9} @ get size and addr of initrd
+ @ r5 = ATAG_CORE
+ @ r6 = ATAG_INITRD2
+ @ r7 = initrd start
+ @ r8 = initrd end
+ @ r9 = param_struct address
+
+ ldr r10, [r9, #4] @ get first tag
+ teq r10, r5 @ is it ATAG_CORE?
+/*
+ * If we didn't find a valid tag list, create a dummy ATAG_CORE entry.
+ */
+ movne r10, #0 @ terminator
+ movne r4, #2 @ Size of this entry (2 words)
+ stmneia r9, {r4, r5, r10} @ Size, ATAG_CORE, terminator
+
+/*
+ * 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 r10, [r9, #0] @ tag length
+ teq r10, #0 @ last tag (zero length)?
+ addne r9, r9, r10, lsl #2
+ bne taglist
+
+ mov r5, #4 @ Size of initrd tag (4 words)
+ stmia r9, {r5, r6, r7, r8, r10}
+ b kernel_start @ call kernel
+
+/*
+ * Move the block of memory length r6 from address r4 to address r5
+ */
+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
+
+ .size _start, . - _start
+
+ .type data,#object
+data: .word initrd_start @ source initrd address
+ .word initrd_phys @ destination initrd address
+ .word initrd_size @ initrd size
+
+ .word 0x54410001 @ r5 = ATAG_CORE
+ .word 0x54420005 @ r6 = ATAG_INITRD2
+ .word initrd_phys @ r7
+ .word initrd_size @ r8
+ .word params_phys @ r9
+ .size data, . - data