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f73670e8 G |
1 | /* |
2 | * linux/arch/unicore32/lib/backtrace.S | |
3 | * | |
4 | * Code specific to PKUnity SoC and UniCore ISA | |
5 | * | |
6 | * Copyright (C) 2001-2010 GUAN Xue-tao | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | #include <linux/linkage.h> | |
13 | #include <asm/assembler.h> | |
14 | .text | |
15 | ||
16 | @ fp is 0 or stack frame | |
17 | ||
18 | #define frame v4 | |
19 | #define sv_fp v5 | |
20 | #define sv_pc v6 | |
21 | #define offset v8 | |
22 | ||
23 | ENTRY(__backtrace) | |
24 | mov r0, fp | |
25 | ||
26 | ENTRY(c_backtrace) | |
27 | ||
28 | #if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK) | |
29 | mov pc, lr | |
30 | ENDPROC(__backtrace) | |
31 | ENDPROC(c_backtrace) | |
32 | #else | |
33 | stm.w (v4 - v8, lr), [sp-] @ Save an extra register | |
34 | @ so we have a location... | |
35 | mov.a frame, r0 @ if frame pointer is zero | |
36 | beq no_frame @ we have no stack frames | |
37 | ||
38 | 1: stm.w (pc), [sp-] @ calculate offset of PC stored | |
39 | ldw.w r0, [sp]+, #4 @ by stmfd for this CPU | |
40 | adr r1, 1b | |
41 | sub offset, r0, r1 | |
42 | ||
43 | /* | |
44 | * Stack frame layout: | |
45 | * optionally saved caller registers (r4 - r10) | |
46 | * saved fp | |
47 | * saved sp | |
48 | * saved lr | |
49 | * frame => saved pc | |
50 | * optionally saved arguments (r0 - r3) | |
51 | * saved sp => <next word> | |
52 | * | |
53 | * Functions start with the following code sequence: | |
54 | * mov ip, sp | |
55 | * stm.w (r0 - r3), [sp-] (optional) | |
56 | * corrected pc => stm.w sp, (..., fp, ip, lr, pc) | |
57 | */ | |
58 | for_each_frame: | |
59 | ||
60 | 1001: ldw sv_pc, [frame+], #0 @ get saved pc | |
61 | 1002: ldw sv_fp, [frame+], #-12 @ get saved fp | |
62 | ||
63 | sub sv_pc, sv_pc, offset @ Correct PC for prefetching | |
64 | ||
65 | 1003: ldw r2, [sv_pc+], #-4 @ if stmfd sp, {args} exists, | |
66 | ldw r3, .Ldsi+4 @ adjust saved 'pc' back one | |
67 | cxor.a r3, r2 >> #14 @ instruction | |
68 | beq 201f | |
69 | sub r0, sv_pc, #4 @ allow for mov | |
70 | b 202f | |
71 | 201: | |
72 | sub r0, sv_pc, #8 @ allow for mov + stmia | |
73 | 202: | |
74 | ldw r1, [frame+], #-4 @ get saved lr | |
75 | mov r2, frame | |
76 | b.l dump_backtrace_entry | |
77 | ||
78 | ldw r1, [sv_pc+], #-4 @ if stmfd sp, {args} exists, | |
79 | ldw r3, .Ldsi+4 | |
80 | cxor.a r3, r1 >> #14 | |
81 | bne 1004f | |
82 | ldw r0, [frame+], #-8 @ get sp | |
83 | sub r0, r0, #4 @ point at the last arg | |
84 | b.l .Ldumpstm @ dump saved registers | |
85 | ||
86 | 1004: ldw r1, [sv_pc+], #0 @ if stmfd {, fp, ip, lr, pc} | |
87 | ldw r3, .Ldsi @ instruction exists, | |
88 | cxor.a r3, r1 >> #14 | |
89 | bne 201f | |
90 | sub r0, frame, #16 | |
91 | b.l .Ldumpstm @ dump saved registers | |
92 | 201: | |
93 | cxor.a sv_fp, #0 @ zero saved fp means | |
94 | beq no_frame @ no further frames | |
95 | ||
96 | csub.a sv_fp, frame @ next frame must be | |
97 | mov frame, sv_fp @ above the current frame | |
98 | bua for_each_frame | |
99 | ||
100 | 1006: adr r0, .Lbad | |
101 | mov r1, frame | |
102 | b.l printk | |
103 | no_frame: ldm.w (v4 - v8, pc), [sp]+ | |
104 | ENDPROC(__backtrace) | |
105 | ENDPROC(c_backtrace) | |
106 | ||
107 | .pushsection __ex_table,"a" | |
108 | .align 3 | |
109 | .long 1001b, 1006b | |
110 | .long 1002b, 1006b | |
111 | .long 1003b, 1006b | |
112 | .long 1004b, 1006b | |
113 | .popsection | |
114 | ||
115 | #define instr v4 | |
116 | #define reg v5 | |
117 | #define stack v6 | |
118 | ||
119 | .Ldumpstm: stm.w (instr, reg, stack, v7, lr), [sp-] | |
120 | mov stack, r0 | |
121 | mov instr, r1 | |
122 | mov reg, #14 | |
123 | mov v7, #0 | |
124 | 1: mov r3, #1 | |
125 | csub.a reg, #8 | |
126 | bne 201f | |
127 | sub reg, reg, #3 | |
128 | 201: | |
129 | cand.a instr, r3 << reg | |
130 | beq 2f | |
131 | add v7, v7, #1 | |
132 | cxor.a v7, #6 | |
133 | cmoveq v7, #1 | |
134 | cmoveq r1, #'\n' | |
135 | cmovne r1, #' ' | |
136 | ldw.w r3, [stack]+, #-4 | |
137 | mov r2, reg | |
138 | csub.a r2, #8 | |
139 | bsl 201f | |
140 | sub r2, r2, #3 | |
141 | 201: | |
142 | cand.a instr, #0x40 @ if H is 1, high 16 regs | |
143 | beq 201f | |
144 | add r2, r2, #0x10 @ so r2 need add 16 | |
145 | 201: | |
146 | adr r0, .Lfp | |
147 | b.l printk | |
148 | 2: sub.a reg, reg, #1 | |
149 | bns 1b | |
150 | cxor.a v7, #0 | |
151 | beq 201f | |
152 | adr r0, .Lcr | |
153 | b.l printk | |
154 | 201: ldm.w (instr, reg, stack, v7, pc), [sp]+ | |
155 | ||
156 | .Lfp: .asciz "%cr%d:%08x" | |
157 | .Lcr: .asciz "\n" | |
158 | .Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" | |
159 | .align | |
160 | .Ldsi: .word 0x92eec000 >> 14 @ stm.w sp, (... fp, ip, lr, pc) | |
161 | .word 0x92e10000 >> 14 @ stm.w sp, () | |
162 | ||
163 | #endif |