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
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
/*-
* Copyright (c) 2008 Semihalf, Rafal Czubak
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <machine/asm.h>
#include <machine/armreg.h>
.text
.extern _C_LABEL(self_reloc), _C_LABEL(main)
.weak _DYNAMIC
/*
* Entry point to the loader that U-Boot passes control to.
*/
.globl _start
_start:
#ifdef _ARM_ARCH_6
mrc p15, 0, ip, c1, c0, 0
orr ip, ip, #(CPU_CONTROL_UNAL_ENABLE)
orr ip, ip, #(CPU_CONTROL_AFLT_ENABLE)
mcr p15, 0, ip, c1, c0, 0
#endif
/*
* Save r0 and r1 (argc and argv passed from u-boot), and lr (trashed
* by the call to self_reloc below) until we're ready to call main().
*/
push {r0, r1, lr}
/*
* Do self-relocation when the weak external symbol _DYNAMIC is non-NULL.
* When linked as a dynamic relocatable file, the linker automatically
* defines _DYNAMIC with a value that is the offset of the dynamic
* relocation info section.
* Note that we're still on u-boot's stack here, but the self_reloc
* code uses only a couple dozen bytes of stack space.
*/
adr ip, .here_off /* .here_off is a symbol whose value */
ldr r0, [ip] /* is its own offset in the text seg. */
sub r0, ip, r0 /* Get its pc-relative address and */
ldr r1, .dynamic_off /* subtract its value and we get */
teq r1, #0 /* r0 = physaddr we were loaded at. */
addne r1, r1, r0 /* r1 = dynamic section physaddr. */
blne _C_LABEL(self_reloc) /* Do reloc if _DYNAMIC is non-NULL. */
/* Hint where to look for the API signature */
ldr ip, =uboot_address
str sp, [ip]
/* Save U-Boot's r8 and r9 */
ldr ip, =saved_regs
str r8, [ip, #0]
str r9, [ip, #4]
/*
* First restore argc, argv, and the u-boot return address, then
* Start loader. This is basically a tail-recursion call; if main()
* returns, it returns to u-boot (which reports the value returned r0).
*/
pop {r0, r1, lr}
b main
/*
* Data for self-relocation, in the text segment for pc-rel access.
*/
.here_off:
.word .
.dynamic_off:
.word _DYNAMIC
/*
* syscall()
*/
ENTRY(syscall)
/* Save caller's lr, r8 and r9 */
ldr ip, =saved_regs
str r8, [ip, #8]
str r9, [ip, #12]
str lr, [ip, #16]
/* Restore U-Boot's r8 and r9 */
ldr r8, [ip, #0]
ldr r9, [ip, #4]
/* Call into U-Boot */
ldr lr, =return_from_syscall
ldr ip, =syscall_ptr
ldr pc, [ip]
return_from_syscall:
/* Restore loader's r8, r9 and lr */
ldr ip, =saved_regs
ldr lr, [ip, #16]
ldr r9, [ip, #12]
ldr r8, [ip, #8]
/* Return to caller */
mov pc, lr
/*
* Data section
*/
.data
.align 4
.globl syscall_ptr
syscall_ptr:
.long 0
.globl uboot_address
uboot_address:
.long 0
saved_regs:
.long 0 /* U-Boot's r8 */
.long 0 /* U-Boot's r9 */
.long 0 /* Loader's r8 */
.long 0 /* Loader's r9 */
.long 0 /* Loader's lr */
|
