diff options
Diffstat (limited to 'arch/arm/lib/backtrace.S')
| -rw-r--r-- | arch/arm/lib/backtrace.S | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S new file mode 100644 index 000000000000..68a21c0f3f52 --- /dev/null +++ b/arch/arm/lib/backtrace.S @@ -0,0 +1,157 @@ +/* + * 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) + +#ifndef CONFIG_FRAME_POINTER + 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 + LOADREGS(eqfd, 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 + LOADREGS(eqfd, 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 + LOADREGS(fd, 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, 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 + LOADREGS(fd, sp!, {instr, reg, stack, r7, 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 |