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