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Diffstat (limited to 'arch/arm/lib/backtrace.S')
| -rw-r--r-- | arch/arm/lib/backtrace.S | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S new file mode 100644 index 0000000..b0951d0 --- /dev/null +++ b/arch/arm/lib/backtrace.S @@ -0,0 +1,154 @@ +/* + * 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? + moveq mask, #0xfc000003 @ mask for 26-bit + 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) + + .section __ex_table,"a" + .align 3 + .long 1001b, 1006b + .long 1002b, 1006b + .long 1003b, 1006b + .long 1004b, 1006b + .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, #10 + mov r7, #0 +1: mov r3, #1 + tst instr, r3, lsl reg + 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 |
