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1/*
2 * linux/arch/arm/lib/backtrace.S
3 *
4 * Copyright (C) 1995, 1996 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 * 27/03/03 Ian Molton Clean up CONFIG_CPU
11 *
12 */
13#include <linux/linkage.h>
14#include <asm/assembler.h>
15 .text
16
17@ fp is 0 or stack frame
18
19#define frame r4
20#define sv_fp r5
21#define sv_pc r6
22#define mask r7
23#define offset r8
24
25ENTRY(__backtrace)
26 mov r1, #0x10
27 mov r0, fp
28
29ENTRY(c_backtrace)
30
31#if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK)
32 mov pc, lr
33ENDPROC(__backtrace)
34ENDPROC(c_backtrace)
35#else
36 stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location...
37 movs frame, r0 @ if frame pointer is zero
38 beq no_frame @ we have no stack frames
39
40 tst r1, #0x10 @ 26 or 32-bit mode?
41 ARM( moveq mask, #0xfc000003 )
42 THUMB( moveq mask, #0xfc000000 )
43 THUMB( orreq mask, #0x03 )
44 movne mask, #0 @ mask for 32-bit
45
461: stmfd sp!, {pc} @ calculate offset of PC stored
47 ldr r0, [sp], #4 @ by stmfd for this CPU
48 adr r1, 1b
49 sub offset, r0, r1
50
51/*
52 * Stack frame layout:
53 * optionally saved caller registers (r4 - r10)
54 * saved fp
55 * saved sp
56 * saved lr
57 * frame => saved pc
58 * optionally saved arguments (r0 - r3)
59 * saved sp => <next word>
60 *
61 * Functions start with the following code sequence:
62 * mov ip, sp
63 * stmfd sp!, {r0 - r3} (optional)
64 * corrected pc => stmfd sp!, {..., fp, ip, lr, pc}
65 */
66for_each_frame: tst frame, mask @ Check for address exceptions
67 bne no_frame
68
691001: ldr sv_pc, [frame, #0] @ get saved pc
701002: ldr sv_fp, [frame, #-12] @ get saved fp
71
72 sub sv_pc, sv_pc, offset @ Correct PC for prefetching
73 bic sv_pc, sv_pc, mask @ mask PC/LR for the mode
74
751003: ldr r2, [sv_pc, #-4] @ if stmfd sp!, {args} exists,
76 ldr r3, .Ldsi+4 @ adjust saved 'pc' back one
77 teq r3, r2, lsr #10 @ instruction
78 subne r0, sv_pc, #4 @ allow for mov
79 subeq r0, sv_pc, #8 @ allow for mov + stmia
80
81 ldr r1, [frame, #-4] @ get saved lr
82 mov r2, frame
83 bic r1, r1, mask @ mask PC/LR for the mode
84 bl dump_backtrace_entry
85
86 ldr r1, [sv_pc, #-4] @ if stmfd sp!, {args} exists,
87 ldr r3, .Ldsi+4
88 teq r3, r1, lsr #10
89 ldreq r0, [frame, #-8] @ get sp
90 subeq r0, r0, #4 @ point at the last arg
91 bleq .Ldumpstm @ dump saved registers
92
931004: ldr r1, [sv_pc, #0] @ if stmfd sp!, {..., fp, ip, lr, pc}
94 ldr r3, .Ldsi @ instruction exists,
95 teq r3, r1, lsr #10
96 subeq r0, frame, #16
97 bleq .Ldumpstm @ dump saved registers
98
99 teq sv_fp, #0 @ zero saved fp means
100 beq no_frame @ no further frames
101
102 cmp sv_fp, frame @ next frame must be
103 mov frame, sv_fp @ above the current frame
104 bhi for_each_frame
105
1061006: adr r0, .Lbad
107 mov r1, frame
108 bl printk
109no_frame: ldmfd sp!, {r4 - r8, pc}
110ENDPROC(__backtrace)
111ENDPROC(c_backtrace)
112
113 .pushsection __ex_table,"a"
114 .align 3
115 .long 1001b, 1006b
116 .long 1002b, 1006b
117 .long 1003b, 1006b
118 .long 1004b, 1006b
119 .popsection
120
121#define instr r4
122#define reg r5
123#define stack r6
124
125.Ldumpstm: stmfd sp!, {instr, reg, stack, r7, lr}
126 mov stack, r0
127 mov instr, r1
128 mov reg, #10
129 mov r7, #0
1301: mov r3, #1
131 ARM( tst instr, r3, lsl reg )
132 THUMB( lsl r3, reg )
133 THUMB( tst instr, r3 )
134 beq 2f
135 add r7, r7, #1
136 teq r7, #6
137 moveq r7, #1
138 moveq r1, #'\n'
139 movne r1, #' '
140 ldr r3, [stack], #-4
141 mov r2, reg
142 adr r0, .Lfp
143 bl printk
1442: subs reg, reg, #1
145 bpl 1b
146 teq r7, #0
147 adrne r0, .Lcr
148 blne printk
149 ldmfd sp!, {instr, reg, stack, r7, pc}
150
151.Lfp: .asciz "%cr%d:%08x"
152.Lcr: .asciz "\n"
153.Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n"
154 .align
155.Ldsi: .word 0xe92dd800 >> 10 @ stmfd sp!, {... fp, ip, lr, pc}
156 .word 0xe92d0000 >> 10 @ stmfd sp!, {}
157
158#endif
1/*
2 * linux/arch/arm/lib/backtrace.S
3 *
4 * Copyright (C) 1995, 1996 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 * 27/03/03 Ian Molton Clean up CONFIG_CPU
11 *
12 */
13#include <linux/kern_levels.h>
14#include <linux/linkage.h>
15#include <asm/assembler.h>
16 .text
17
18@ fp is 0 or stack frame
19
20#define frame r4
21#define sv_fp r5
22#define sv_pc r6
23#define mask r7
24#define offset r8
25
26ENTRY(c_backtrace)
27
28#if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK)
29 ret lr
30ENDPROC(c_backtrace)
31#else
32 stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location...
33 movs frame, r0 @ if frame pointer is zero
34 beq no_frame @ we have no stack frames
35
36 tst r1, #0x10 @ 26 or 32-bit mode?
37 ARM( moveq mask, #0xfc000003 )
38 THUMB( moveq mask, #0xfc000000 )
39 THUMB( orreq mask, #0x03 )
40 movne mask, #0 @ mask for 32-bit
41
421: stmfd sp!, {pc} @ calculate offset of PC stored
43 ldr r0, [sp], #4 @ by stmfd for this CPU
44 adr r1, 1b
45 sub offset, r0, r1
46
47/*
48 * Stack frame layout:
49 * optionally saved caller registers (r4 - r10)
50 * saved fp
51 * saved sp
52 * saved lr
53 * frame => saved pc
54 * optionally saved arguments (r0 - r3)
55 * saved sp => <next word>
56 *
57 * Functions start with the following code sequence:
58 * mov ip, sp
59 * stmfd sp!, {r0 - r3} (optional)
60 * corrected pc => stmfd sp!, {..., fp, ip, lr, pc}
61 */
62for_each_frame: tst frame, mask @ Check for address exceptions
63 bne no_frame
64
651001: ldr sv_pc, [frame, #0] @ get saved pc
661002: ldr sv_fp, [frame, #-12] @ get saved fp
67
68 sub sv_pc, sv_pc, offset @ Correct PC for prefetching
69 bic sv_pc, sv_pc, mask @ mask PC/LR for the mode
70
711003: ldr r2, [sv_pc, #-4] @ if stmfd sp!, {args} exists,
72 ldr r3, .Ldsi+4 @ adjust saved 'pc' back one
73 teq r3, r2, lsr #10 @ instruction
74 subne r0, sv_pc, #4 @ allow for mov
75 subeq r0, sv_pc, #8 @ allow for mov + stmia
76
77 ldr r1, [frame, #-4] @ get saved lr
78 mov r2, frame
79 bic r1, r1, mask @ mask PC/LR for the mode
80 bl dump_backtrace_entry
81
82 ldr r1, [sv_pc, #-4] @ if stmfd sp!, {args} exists,
83 ldr r3, .Ldsi+4
84 teq r3, r1, lsr #11
85 ldreq r0, [frame, #-8] @ get sp
86 subeq r0, r0, #4 @ point at the last arg
87 bleq dump_backtrace_stm @ dump saved registers
88
891004: ldr r1, [sv_pc, #0] @ if stmfd sp!, {..., fp, ip, lr, pc}
90 ldr r3, .Ldsi @ instruction exists,
91 teq r3, r1, lsr #11
92 subeq r0, frame, #16
93 bleq dump_backtrace_stm @ dump saved registers
94
95 teq sv_fp, #0 @ zero saved fp means
96 beq no_frame @ no further frames
97
98 cmp sv_fp, frame @ next frame must be
99 mov frame, sv_fp @ above the current frame
100 bhi for_each_frame
101
1021006: adr r0, .Lbad
103 mov r1, frame
104 bl printk
105no_frame: ldmfd sp!, {r4 - r8, pc}
106ENDPROC(c_backtrace)
107
108 .pushsection __ex_table,"a"
109 .align 3
110 .long 1001b, 1006b
111 .long 1002b, 1006b
112 .long 1003b, 1006b
113 .long 1004b, 1006b
114 .popsection
115
116.Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n"
117 .align
118.Ldsi: .word 0xe92dd800 >> 11 @ stmfd sp!, {... fp, ip, lr, pc}
119 .word 0xe92d0000 >> 11 @ stmfd sp!, {}
120
121#endif