/* * 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 next r5 #define save 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 #else stmfd sp!, {r4 - r8, lr} @ Save an extra register so we have a location... tst r1, #0x10 @ 26 or 32-bit? moveq mask, #0xfc000003 movne mask, #0 tst mask, r0 movne r0, #0 movs frame, r0 1: moveq r0, #-2 ldmeqfd sp!, {r4 - r8, pc} 2: stmfd sp!, {pc} @ calculate offset of PC in STMIA instruction ldr r0, [sp], #4 adr r1, 2b - 4 sub offset, r0, r1 3: tst frame, mask @ Check for address exceptions... bne 1b 1001: ldr next, [frame, #-12] @ get fp 1002: ldr r2, [frame, #-4] @ get lr 1003: ldr r3, [frame, #0] @ get pc sub save, r3, offset @ Correct PC for prefetching bic save, save, mask 1004: ldr r1, [save, #0] @ get instruction at function mov r1, r1, lsr #10 ldr r3, .Ldsi+4 teq r1, r3 subeq save, save, #4 mov r0, save bic r1, r2, mask bl dump_backtrace_entry ldr r0, [frame, #-8] @ get sp sub r0, r0, #4 1005: ldr r1, [save, #4] @ get instruction at function+4 mov r3, r1, lsr #10 ldr r2, .Ldsi+4 teq r3, r2 @ Check for stmia sp!, {args} addeq save, save, #4 @ next instruction bleq .Ldumpstm sub r0, frame, #16 1006: ldr r1, [save, #4] @ Get 'stmia sp!, {rlist, fp, ip, lr, pc}' instruction mov r3, r1, lsr #10 ldr r2, .Ldsi teq r3, r2 bleq .Ldumpstm /* * A zero next framepointer means we're done. */ teq next, #0 ldmeqfd sp!, {r4 - r8, pc} /* * The next framepointer must be above the * current framepointer. */ cmp next, frame mov frame, next bhi 3b b 1007f /* * Fixup for LDMDB. Note that this must not be in the fixup section. */ 1007: ldr r0, =.Lbad mov r1, frame bl printk ldmfd sp!, {r4 - r8, pc} .ltorg .section __ex_table,"a" .align 3 .long 1001b, 1007b .long 1002b, 1007b .long 1003b, 1007b .long 1004b, 1007b .long 1005b, 1007b .long 1006b, 1007b .previous #define instr r4 #define reg r5 #define stack r6 .Ldumpstm: stmfd sp!, {instr, reg, stack, r7, r8, lr} mov stack, r0 mov instr, r1 mov reg, #9 mov r7, #0 1: mov r3, #1 tst instr, r3, lsl reg beq 2f add r7, r7, #1 teq r7, #4 moveq r7, #0 moveq r3, #'\n' movne r3, #' ' ldr r2, [stack], #-4 mov r1, reg adr r0, .Lfp bl printk 2: subs reg, reg, #1 bpl 1b teq r7, #0 adrne r0, .Lcr blne printk mov r0, stack ldmfd sp!, {instr, reg, stack, r7, r8, pc} .Lfp: .asciz " r%d = %08X%c" .Lcr: .asciz "\n" .Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" .align .Ldsi: .word 0x00e92dd8 >> 2 .word 0x00e92d00 >> 2 #endif