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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/*
* linux/arch/arm/lib/backtrace.S
*
* Copyright (C) 1995, 1996 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.
*
* 27/03/03 Ian Molton Clean up CONFIG_CPU
*
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
.text
@ fp is 0 or stack frame
#define frame r4
#define sv_fp r5
#define sv_pc r6
#define mask r7
#define offset r8
ENTRY(__backtrace)
mov r1, #0x10
mov r0, fp
ENTRY(c_backtrace)
#if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK)
mov pc, lr
ENDPROC(__backtrace)
ENDPROC(c_backtrace)
#else
stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location...
movs frame, r0 @ if frame pointer is zero
beq no_frame @ we have no stack frames
tst r1, #0x10 @ 26 or 32-bit mode?
moveq mask, #0xfc000003 @ mask for 26-bit
movne mask, #0 @ mask for 32-bit
1: stmfd sp!, {pc} @ calculate offset of PC stored
ldr r0, [sp], #4 @ by stmfd for this CPU
adr r1, 1b
sub offset, r0, r1
/*
* Stack frame layout:
* optionally saved caller registers (r4 - r10)
* saved fp
* saved sp
* saved lr
* frame => saved pc
* optionally saved arguments (r0 - r3)
* saved sp => <next word>
*
* Functions start with the following code sequence:
* mov ip, sp
* stmfd sp!, {r0 - r3} (optional)
* corrected pc => stmfd sp!, {..., fp, ip, lr, pc}
*/
for_each_frame: tst frame, mask @ Check for address exceptions
bne no_frame
1001: ldr sv_pc, [frame, #0] @ get saved pc
1002: ldr sv_fp, [frame, #-12] @ get saved fp
sub sv_pc, sv_pc, offset @ Correct PC for prefetching
bic sv_pc, sv_pc, mask @ mask PC/LR for the mode
1003: ldr r2, [sv_pc, #-4] @ if stmfd sp!, {args} exists,
ldr r3, .Ldsi+4 @ adjust saved 'pc' back one
teq r3, r2, lsr #10 @ instruction
subne r0, sv_pc, #4 @ allow for mov
subeq r0, sv_pc, #8 @ allow for mov + stmia
ldr r1, [frame, #-4] @ get saved lr
mov r2, frame
bic r1, r1, mask @ mask PC/LR for the mode
bl dump_backtrace_entry
ldr r1, [sv_pc, #-4] @ if stmfd sp!, {args} exists,
ldr r3, .Ldsi+4
teq r3, r1, lsr #10
ldreq r0, [frame, #-8] @ get sp
subeq r0, r0, #4 @ point at the last arg
bleq .Ldumpstm @ dump saved registers
1004: ldr r1, [sv_pc, #0] @ if stmfd sp!, {..., fp, ip, lr, pc}
ldr r3, .Ldsi @ instruction exists,
teq r3, r1, lsr #10
subeq r0, frame, #16
bleq .Ldumpstm @ dump saved registers
teq sv_fp, #0 @ zero saved fp means
beq no_frame @ no further frames
cmp sv_fp, frame @ next frame must be
mov frame, sv_fp @ above the current frame
bhi for_each_frame
1006: adr r0, .Lbad
mov r1, frame
bl printk
no_frame: ldmfd sp!, {r4 - r8, pc}
ENDPROC(__backtrace)
ENDPROC(c_backtrace)
.section __ex_table,"a"
.align 3
.long 1001b, 1006b
.long 1002b, 1006b
.long 1003b, 1006b
.long 1004b, 1006b
.previous
#define instr r4
#define reg r5
#define stack r6
.Ldumpstm: stmfd sp!, {instr, reg, stack, r7, lr}
mov stack, r0
mov instr, r1
mov reg, #10
mov r7, #0
1: mov r3, #1
tst instr, r3, lsl reg
beq 2f
add r7, r7, #1
teq r7, #6
moveq r7, #1
moveq r1, #'\n'
movne r1, #' '
ldr r3, [stack], #-4
mov r2, reg
adr r0, .Lfp
bl printk
2: subs reg, reg, #1
bpl 1b
teq r7, #0
adrne r0, .Lcr
blne printk
ldmfd sp!, {instr, reg, stack, r7, pc}
.Lfp: .asciz "%cr%d:%08x"
.Lcr: .asciz "\n"
.Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n"
.align
.Ldsi: .word 0xe92dd800 >> 10 @ stmfd sp!, {... fp, ip, lr, pc}
.word 0xe92d0000 >> 10 @ stmfd sp!, {}
#endif
|
