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1da177e4 LT |
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 | */ | |
1da177e4 LT |
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 | |
7ab3f8d5 RK |
20 | #define sv_fp r5 |
21 | #define sv_pc r6 | |
1da177e4 LT |
22 | #define mask r7 |
23 | #define offset r8 | |
24 | ||
1da177e4 LT |
25 | ENTRY(c_backtrace) |
26 | ||
3ee357f0 | 27 | #if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK) |
1da177e4 | 28 | mov pc, lr |
93ed3970 | 29 | ENDPROC(c_backtrace) |
1da177e4 | 30 | #else |
1da177e4 | 31 | stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location... |
7ab3f8d5 RK |
32 | movs frame, r0 @ if frame pointer is zero |
33 | beq no_frame @ we have no stack frames | |
34 | ||
35 | tst r1, #0x10 @ 26 or 32-bit mode? | |
8b592783 CM |
36 | ARM( moveq mask, #0xfc000003 ) |
37 | THUMB( moveq mask, #0xfc000000 ) | |
38 | THUMB( orreq mask, #0x03 ) | |
7ab3f8d5 RK |
39 | movne mask, #0 @ mask for 32-bit |
40 | ||
41 | 1: stmfd sp!, {pc} @ calculate offset of PC stored | |
42 | ldr r0, [sp], #4 @ by stmfd for this CPU | |
43 | adr r1, 1b | |
1da177e4 LT |
44 | sub offset, r0, r1 |
45 | ||
7ab3f8d5 RK |
46 | /* |
47 | * Stack frame layout: | |
48 | * optionally saved caller registers (r4 - r10) | |
49 | * saved fp | |
50 | * saved sp | |
51 | * saved lr | |
52 | * frame => saved pc | |
53 | * optionally saved arguments (r0 - r3) | |
54 | * saved sp => <next word> | |
55 | * | |
56 | * Functions start with the following code sequence: | |
57 | * mov ip, sp | |
58 | * stmfd sp!, {r0 - r3} (optional) | |
59 | * corrected pc => stmfd sp!, {..., fp, ip, lr, pc} | |
60 | */ | |
61 | for_each_frame: tst frame, mask @ Check for address exceptions | |
62 | bne no_frame | |
63 | ||
64 | 1001: ldr sv_pc, [frame, #0] @ get saved pc | |
65 | 1002: ldr sv_fp, [frame, #-12] @ get saved fp | |
1da177e4 | 66 | |
7ab3f8d5 RK |
67 | sub sv_pc, sv_pc, offset @ Correct PC for prefetching |
68 | bic sv_pc, sv_pc, mask @ mask PC/LR for the mode | |
69 | ||
70 | 1003: ldr r2, [sv_pc, #-4] @ if stmfd sp!, {args} exists, | |
71 | ldr r3, .Ldsi+4 @ adjust saved 'pc' back one | |
72 | teq r3, r2, lsr #10 @ instruction | |
73 | subne r0, sv_pc, #4 @ allow for mov | |
74 | subeq r0, sv_pc, #8 @ allow for mov + stmia | |
75 | ||
76 | ldr r1, [frame, #-4] @ get saved lr | |
77 | mov r2, frame | |
78 | bic r1, r1, mask @ mask PC/LR for the mode | |
1da177e4 LT |
79 | bl dump_backtrace_entry |
80 | ||
7ab3f8d5 RK |
81 | ldr r1, [sv_pc, #-4] @ if stmfd sp!, {args} exists, |
82 | ldr r3, .Ldsi+4 | |
83 | teq r3, r1, lsr #10 | |
84 | ldreq r0, [frame, #-8] @ get sp | |
85 | subeq r0, r0, #4 @ point at the last arg | |
86 | bleq .Ldumpstm @ dump saved registers | |
1da177e4 | 87 | |
7ab3f8d5 RK |
88 | 1004: ldr r1, [sv_pc, #0] @ if stmfd sp!, {..., fp, ip, lr, pc} |
89 | ldr r3, .Ldsi @ instruction exists, | |
90 | teq r3, r1, lsr #10 | |
91 | subeq r0, frame, #16 | |
92 | bleq .Ldumpstm @ dump saved registers | |
93 | ||
94 | teq sv_fp, #0 @ zero saved fp means | |
95 | beq no_frame @ no further frames | |
96 | ||
97 | cmp sv_fp, frame @ next frame must be | |
98 | mov frame, sv_fp @ above the current frame | |
99 | bhi for_each_frame | |
100 | ||
101 | 1006: adr r0, .Lbad | |
1da177e4 LT |
102 | mov r1, frame |
103 | bl printk | |
7ab3f8d5 | 104 | no_frame: ldmfd sp!, {r4 - r8, pc} |
93ed3970 | 105 | ENDPROC(c_backtrace) |
1da177e4 | 106 | |
4260415f | 107 | .pushsection __ex_table,"a" |
1da177e4 | 108 | .align 3 |
7ab3f8d5 RK |
109 | .long 1001b, 1006b |
110 | .long 1002b, 1006b | |
111 | .long 1003b, 1006b | |
112 | .long 1004b, 1006b | |
4260415f | 113 | .popsection |
1da177e4 LT |
114 | |
115 | #define instr r4 | |
116 | #define reg r5 | |
117 | #define stack r6 | |
118 | ||
7ab3f8d5 | 119 | .Ldumpstm: stmfd sp!, {instr, reg, stack, r7, lr} |
1da177e4 LT |
120 | mov stack, r0 |
121 | mov instr, r1 | |
7ab3f8d5 | 122 | mov reg, #10 |
1da177e4 LT |
123 | mov r7, #0 |
124 | 1: mov r3, #1 | |
8b592783 CM |
125 | ARM( tst instr, r3, lsl reg ) |
126 | THUMB( lsl r3, reg ) | |
127 | THUMB( tst instr, r3 ) | |
1da177e4 LT |
128 | beq 2f |
129 | add r7, r7, #1 | |
7ab3f8d5 RK |
130 | teq r7, #6 |
131 | moveq r7, #1 | |
132 | moveq r1, #'\n' | |
133 | movne r1, #' ' | |
134 | ldr r3, [stack], #-4 | |
135 | mov r2, reg | |
1da177e4 LT |
136 | adr r0, .Lfp |
137 | bl printk | |
138 | 2: subs reg, reg, #1 | |
139 | bpl 1b | |
140 | teq r7, #0 | |
141 | adrne r0, .Lcr | |
142 | blne printk | |
7ab3f8d5 | 143 | ldmfd sp!, {instr, reg, stack, r7, pc} |
1da177e4 | 144 | |
7ab3f8d5 | 145 | .Lfp: .asciz "%cr%d:%08x" |
1da177e4 LT |
146 | .Lcr: .asciz "\n" |
147 | .Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" | |
148 | .align | |
7ab3f8d5 RK |
149 | .Ldsi: .word 0xe92dd800 >> 10 @ stmfd sp!, {... fp, ip, lr, pc} |
150 | .word 0xe92d0000 >> 10 @ stmfd sp!, {} | |
1da177e4 LT |
151 | |
152 | #endif |