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#include <linux/config.h> 11#include <linux/linkage.h> 12#include <asm/assembler.h> 13 .text 14 15@ fp is 0 or stack frame 16 17#define frame r4 18#define next r5 19#define save r6 20#define mask r7 21#define offset r8 22 23ENTRY(__backtrace) 24 mov r1, #0x10 25 mov r0, fp 26 27ENTRY(c_backtrace) 28 29#ifndef CONFIG_FRAME_POINTER 30 mov pc, lr 31#else 32 33 stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location... 34#ifdef CONFIG_CPU_32 35 tst r1, #0x10 @ 26 or 32-bit? 36 moveq mask, #0xfc000003 37 movne mask, #0 38#else 39 mov mask, #0xfc000003 40#endif 41 tst mask, r0 42 movne r0, #0 43 movs frame, r0 441: moveq r0, #-2 45 LOADREGS(eqfd, sp!, {r4 - r8, pc}) 46 472: stmfd sp!, {pc} @ calculate offset of PC in STMIA instruction 48 ldr r0, [sp], #4 49 adr r1, 2b - 4 50 sub offset, r0, r1 51 523: tst frame, mask @ Check for address exceptions... 53 bne 1b 54 551001: ldmda frame, {r0, r1, r2, r3} @ fp, sp, lr, pc 56 mov next, r0 57 58 sub save, r3, offset @ Correct PC for prefetching 59 bic save, save, mask 60 adr r0, .Lfe 61 mov r1, save 62 bic r2, r2, mask 63 bl SYMBOL_NAME(printk) @ print pc and link register 64 65 sub r0, frame, #16 661002: ldr r1, [save, #4] @ get instruction at function+4 67 mov r3, r1, lsr #10 68 ldr r2, .Ldsi+4 69 teq r3, r2 @ Check for stmia sp!, {args} 70 addeq save, save, #4 @ next instruction 71 bleq .Ldumpstm 72 731003: ldr r1, [save, #4] @ Get 'stmia sp!, {rlist, fp, ip, lr, pc}' instruction 74 mov r3, r1, lsr #10 75 ldr r2, .Ldsi 76 teq r3, r2 77 bleq .Ldumpstm 78 79 teq frame, next 80 movne frame, next 81 teqne frame, #0 82 bne 3b 83 LOADREGS(fd, sp!, {r4 - r8, pc}) 84 85/* 86 * Fixup for LDMDB 87 */ 88 .section .fixup,"ax" 89 .align 0 901004: ldr r0, =.Lbad 91 mov r1, frame 92 bl SYMBOL_NAME(printk) 93 LOADREGS(fd, sp!, {r4 - r8, pc}) 94 .ltorg 95 .previous 96 97 .section __ex_table,"a" 98 .align 3 99 .long 1001b, 1004b 100 .long 1002b, 1004b 101 .long 1003b, 1004b 102 .previous 103 104#define instr r4 105#define reg r5 106#define stack r6 107 108.Ldumpstm: stmfd sp!, {instr, reg, stack, r7, lr} 109 mov stack, r0 110 mov instr, r1 111 mov reg, #9 112 mov r7, #0 1131: mov r3, #1 114 tst instr, r3, lsl reg 115 beq 2f 116 add r7, r7, #1 117 teq r7, #4 118 moveq r7, #0 119 moveq r3, #'\n' 120 movne r3, #' ' 121 ldr r2, [stack], #-4 122 mov r1, reg 123 adr r0, .Lfp 124 bl SYMBOL_NAME(printk) 1252: subs reg, reg, #1 126 bpl 1b 127 teq r7, #0 128 adrne r0, .Lcr 129 blne SYMBOL_NAME(printk) 130 mov r0, stack 131 LOADREGS(fd, sp!, {instr, reg, stack, r7, pc}) 132 133.Lfe: .asciz "Function entered at [<%p>] from [<%p>]\n" 134.Lfp: .asciz " r%d = %08X%c" 135.Lcr: .asciz "\n" 136.Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" 137 .align 138.Ldsi: .word 0x00e92dd8 >> 2 139 .word 0x00e92d00 >> 2 140 141#endif 142