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/*

 *  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 

#include 

                .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

#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 => 

 *

 * 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}

                .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