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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 | /* * 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? ARM( moveq mask, #0xfc000003 ) THUMB( moveq mask, #0xfc000000 ) THUMB( orreq mask, #0x03 ) 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) .pushsection __ex_table,"a" .align 3 .long 1001b, 1006b .long 1002b, 1006b .long 1003b, 1006b .long 1004b, 1006b .popsection #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 ARM( tst instr, r3, lsl reg ) THUMB( lsl r3, reg ) THUMB( tst instr, r3 ) 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 |