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| /*
| * linux/arch/unicore32/lib/backtrace.S
| *
| * Code specific to PKUnity SoC and UniCore ISA
| *
| * Copyright (C) 2001-2010 GUAN Xue-tao
| *
| * 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.
| */
| #include <linux/linkage.h>
| #include <asm/assembler.h>
| .text
|
| @ fp is 0 or stack frame
|
| #define frame v4
| #define sv_fp v5
| #define sv_pc v6
| #define offset v8
|
| ENTRY(__backtrace)
| mov r0, fp
|
| ENTRY(c_backtrace)
|
| #if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK)
| mov pc, lr
| ENDPROC(__backtrace)
| ENDPROC(c_backtrace)
| #else
| stm.w (v4 - v8, lr), [sp-] @ Save an extra register
| @ so we have a location...
| mov.a frame, r0 @ if frame pointer is zero
| beq no_frame @ we have no stack frames
|
| 1: stm.w (pc), [sp-] @ calculate offset of PC stored
| ldw.w 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
| * stm.w (r0 - r3), [sp-] (optional)
| * corrected pc => stm.w sp, (..., fp, ip, lr, pc)
| */
| for_each_frame:
|
| 1001: ldw sv_pc, [frame+], #0 @ get saved pc
| 1002: ldw sv_fp, [frame+], #-12 @ get saved fp
|
| sub sv_pc, sv_pc, offset @ Correct PC for prefetching
|
| 1003: ldw r2, [sv_pc+], #-4 @ if stmfd sp, {args} exists,
| ldw r3, .Ldsi+4 @ adjust saved 'pc' back one
| cxor.a r3, r2 >> #14 @ instruction
| beq 201f
| sub r0, sv_pc, #4 @ allow for mov
| b 202f
| 201:
| sub r0, sv_pc, #8 @ allow for mov + stmia
| 202:
| ldw r1, [frame+], #-4 @ get saved lr
| mov r2, frame
| b.l dump_backtrace_entry
|
| ldw r1, [sv_pc+], #-4 @ if stmfd sp, {args} exists,
| ldw r3, .Ldsi+4
| cxor.a r3, r1 >> #14
| bne 1004f
| ldw r0, [frame+], #-8 @ get sp
| sub r0, r0, #4 @ point at the last arg
| b.l .Ldumpstm @ dump saved registers
|
| 1004: ldw r1, [sv_pc+], #0 @ if stmfd {, fp, ip, lr, pc}
| ldw r3, .Ldsi @ instruction exists,
| cxor.a r3, r1 >> #14
| bne 201f
| sub r0, frame, #16
| b.l .Ldumpstm @ dump saved registers
| 201:
| cxor.a sv_fp, #0 @ zero saved fp means
| beq no_frame @ no further frames
|
| csub.a sv_fp, frame @ next frame must be
| mov frame, sv_fp @ above the current frame
| bua for_each_frame
|
| 1006: adr r0, .Lbad
| mov r1, frame
| b.l printk
| no_frame: ldm.w (v4 - v8, pc), [sp]+
| ENDPROC(__backtrace)
| ENDPROC(c_backtrace)
|
| .pushsection __ex_table,"a"
| .align 3
| .long 1001b, 1006b
| .long 1002b, 1006b
| .long 1003b, 1006b
| .long 1004b, 1006b
| .popsection
|
| #define instr v4
| #define reg v5
| #define stack v6
|
| .Ldumpstm: stm.w (instr, reg, stack, v7, lr), [sp-]
| mov stack, r0
| mov instr, r1
| mov reg, #14
| mov v7, #0
| 1: mov r3, #1
| csub.a reg, #8
| bne 201f
| sub reg, reg, #3
| 201:
| cand.a instr, r3 << reg
| beq 2f
| add v7, v7, #1
| cxor.a v7, #6
| cmoveq v7, #1
| cmoveq r1, #'\n'
| cmovne r1, #' '
| ldw.w r3, [stack]+, #-4
| mov r2, reg
| csub.a r2, #8
| bsl 201f
| sub r2, r2, #3
| 201:
| cand.a instr, #0x40 @ if H is 1, high 16 regs
| beq 201f
| add r2, r2, #0x10 @ so r2 need add 16
| 201:
| adr r0, .Lfp
| b.l printk
| 2: sub.a reg, reg, #1
| bns 1b
| cxor.a v7, #0
| beq 201f
| adr r0, .Lcr
| b.l printk
| 201: ldm.w (instr, reg, stack, v7, pc), [sp]+
|
| .Lfp: .asciz "%cr%d:%08x"
| .Lcr: .asciz "\n"
| .Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n"
| .align
| .Ldsi: .word 0x92eec000 >> 14 @ stm.w sp, (... fp, ip, lr, pc)
| .word 0x92e10000 >> 14 @ stm.w sp, ()
|
| #endif
|
|
