Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux
[~shefty/rdma-dev.git] / arch / arm / boot / bootp / init.S
1 /*
2  *  linux/arch/arm/boot/bootp/init.S
3  *
4  *  Copyright (C) 2000-2003 Russell King.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  *  "Header" file for splitting kernel + initrd.  Note that we pass
11  *  r0 through to r3 straight through.
12  *
13  *  This demonstrates how to append code to the start of the kernel
14  *  zImage, and boot the kernel without copying it around.  This
15  *  example would be simpler; if we didn't have an object of unknown
16  *  size immediately following the kernel, we could build this into
17  *  a binary blob, and concatenate the zImage using the cat command.
18  */
19                 .section .start,#alloc,#execinstr
20                 .type   _start, #function
21                 .globl  _start
22
23 _start:         add     lr, pc, #-0x8           @ lr = current load addr
24                 adr     r13, data
25                 ldmia   r13!, {r4-r6}           @ r5 = dest, r6 = length
26                 add     r4, r4, lr              @ r4 = initrd_start + load addr
27                 bl      move                    @ move the initrd
28
29 /*
30  * Setup the initrd parameters to pass to the kernel.  This can only be
31  * passed in via the tagged list.
32  */
33                 ldmia   r13, {r5-r9}            @ get size and addr of initrd
34                                                 @ r5 = ATAG_CORE
35                                                 @ r6 = ATAG_INITRD2
36                                                 @ r7 = initrd start
37                                                 @ r8 = initrd end
38                                                 @ r9 = param_struct address
39
40                 ldr     r10, [r9, #4]           @ get first tag
41                 teq     r10, r5                 @ is it ATAG_CORE?
42 /*
43  * If we didn't find a valid tag list, create a dummy ATAG_CORE entry.
44  */
45                 movne   r10, #0                 @ terminator
46                 movne   r4, #2                  @ Size of this entry (2 words)
47                 stmneia r9, {r4, r5, r10}       @ Size, ATAG_CORE, terminator
48
49 /*
50  * find the end of the tag list, and then add an INITRD tag on the end.
51  * If there is already an INITRD tag, then we ignore it; the last INITRD
52  * tag takes precedence.
53  */
54 taglist:        ldr     r10, [r9, #0]           @ tag length
55                 teq     r10, #0                 @ last tag (zero length)?
56                 addne   r9, r9, r10, lsl #2
57                 bne     taglist
58
59                 mov     r5, #4                  @ Size of initrd tag (4 words)
60                 stmia   r9, {r5, r6, r7, r8, r10}
61                 b       kernel_start            @ call kernel
62
63 /*
64  * Move the block of memory length r6 from address r4 to address r5
65  */
66 move:           ldmia   r4!, {r7 - r10}         @ move 32-bytes at a time
67                 stmia   r5!, {r7 - r10}
68                 ldmia   r4!, {r7 - r10}
69                 stmia   r5!, {r7 - r10}
70                 subs    r6, r6, #8 * 4
71                 bcs     move
72                 mov     pc, lr
73
74                 .size   _start, . - _start
75
76                 .align
77
78                 .type   data,#object
79 data:           .word   initrd_start            @ source initrd address
80                 .word   initrd_phys             @ destination initrd address
81                 .word   initrd_size             @ initrd size
82
83                 .word   0x54410001              @ r5 = ATAG_CORE
84                 .word   0x54420005              @ r6 = ATAG_INITRD2
85                 .word   initrd_phys             @ r7
86                 .word   initrd_size             @ r8
87                 .word   params_phys             @ r9
88                 .size   data, . - data