/*
* 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/config.h>
#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
*/
.section .fixup,"ax"
.align 0
1007: ldr r0, =.Lbad
mov r1, frame
bl printk
ldmfd sp!, {r4 - r8, pc}
.ltorg
.previous
.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
