164 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			164 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
/*
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 * linux/arch/unicore32/lib/backtrace.S
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 *
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 * Code specific to PKUnity SoC and UniCore ISA
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 *
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 * Copyright (C) 2001-2010 GUAN Xue-tao
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License version 2 as
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 * published by the Free Software Foundation.
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 */
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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		.text
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@ fp is 0 or stack frame
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#define frame	v4
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#define sv_fp	v5
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#define sv_pc	v6
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#define offset	v8
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ENTRY(__backtrace)
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		mov	r0, fp
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ENTRY(c_backtrace)
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#if !defined(CONFIG_FRAME_POINTER) || !defined(CONFIG_PRINTK)
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		mov	pc, lr
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ENDPROC(__backtrace)
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ENDPROC(c_backtrace)
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#else
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		stm.w	(v4 - v8, lr), [sp-]	@ Save an extra register
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						@ so we have a location...
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		mov.a	frame, r0		@ if frame pointer is zero
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		beq	no_frame		@ we have no stack frames
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1:		stm.w	(pc), [sp-]		@ calculate offset of PC stored
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		ldw.w	r0, [sp]+, #4		@ by stmfd for this CPU
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		adr	r1, 1b
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		sub	offset, r0, r1
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/*
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 * Stack frame layout:
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 *             optionally saved caller registers (r4 - r10)
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 *             saved fp
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 *             saved sp
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 *             saved lr
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 *    frame => saved pc
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 *             optionally saved arguments (r0 - r3)
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 * saved sp => <next word>
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 *
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 * Functions start with the following code sequence:
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 *                  mov   ip, sp
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 *                  stm.w (r0 - r3), [sp-] (optional)
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 * corrected pc =>  stm.w sp, (..., fp, ip, lr, pc)
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 */
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for_each_frame:
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1001:		ldw	sv_pc, [frame+], #0	@ get saved pc
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1002:		ldw	sv_fp, [frame+], #-12	@ get saved fp
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		sub	sv_pc, sv_pc, offset	@ Correct PC for prefetching
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1003:		ldw	r2, [sv_pc+], #-4	@ if stmfd sp, {args} exists,
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		ldw	r3, .Ldsi+4		@ adjust saved 'pc' back one
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		cxor.a	r3, r2 >> #14		@ instruction
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		beq	201f
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		sub	r0, sv_pc, #4		@ allow for mov
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		b	202f
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201:
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		sub	r0, sv_pc, #8		@ allow for mov + stmia
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202:
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		ldw	r1, [frame+], #-4	@ get saved lr
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		mov	r2, frame
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		b.l	dump_backtrace_entry
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		ldw	r1, [sv_pc+], #-4	@ if stmfd sp, {args} exists,
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		ldw	r3, .Ldsi+4
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		cxor.a	r3, r1 >> #14
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		bne	1004f
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		ldw	r0, [frame+], #-8	@ get sp
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		sub	r0, r0, #4		@ point at the last arg
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		b.l	.Ldumpstm		@ dump saved registers
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1004:		ldw	r1, [sv_pc+], #0	@ if stmfd {, fp, ip, lr, pc}
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		ldw	r3, .Ldsi		@ instruction exists,
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		cxor.a	r3, r1 >> #14
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		bne	201f
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		sub	r0, frame, #16
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		b.l	.Ldumpstm		@ dump saved registers
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201:
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		cxor.a	sv_fp, #0		@ zero saved fp means
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		beq	no_frame		@ no further frames
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		csub.a	sv_fp, frame		@ next frame must be
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		mov	frame, sv_fp		@ above the current frame
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		bua	for_each_frame
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1006:		adr	r0, .Lbad
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		mov	r1, frame
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		b.l	printk
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no_frame:	ldm.w	(v4 - v8, pc), [sp]+
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ENDPROC(__backtrace)
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ENDPROC(c_backtrace)
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		.pushsection __ex_table,"a"
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		.align	3
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		.long	1001b, 1006b
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		.long	1002b, 1006b
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		.long	1003b, 1006b
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		.long	1004b, 1006b
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		.popsection
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#define instr v4
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#define reg   v5
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#define stack v6
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.Ldumpstm:	stm.w	(instr, reg, stack, v7, lr), [sp-]
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		mov	stack, r0
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		mov	instr, r1
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		mov	reg, #14
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		mov	v7, #0
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1:		mov	r3, #1
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		csub.a	reg, #8
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		bne	201f
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		sub	reg, reg, #3
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201:
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		cand.a	instr, r3 << reg
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		beq	2f
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		add	v7, v7, #1
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		cxor.a	v7, #6
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		cmoveq	v7, #1
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		cmoveq	r1, #'\n'
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		cmovne	r1, #' '
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		ldw.w	r3, [stack]+, #-4
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		mov	r2, reg
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		csub.a	r2, #8
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		bsl	201f
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		sub	r2, r2, #3
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201:
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		cand.a	instr, #0x40		@ if H is 1, high 16 regs
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		beq	201f
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		add	r2, r2, #0x10		@ so r2 need add 16
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201:
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		adr	r0, .Lfp
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		b.l	printk
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2:		sub.a	reg, reg, #1
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		bns	1b
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		cxor.a	v7, #0
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		beq	201f
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		adr	r0, .Lcr
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		b.l	printk
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201:		ldm.w	(instr, reg, stack, v7, pc), [sp]+
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.Lfp:		.asciz	"%cr%d:%08x"
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.Lcr:		.asciz	"\n"
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.Lbad:		.asciz	"Backtrace aborted due to bad frame pointer <%p>\n"
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		.align
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.Ldsi:		.word	0x92eec000 >> 14	@ stm.w sp, (... fp, ip, lr, pc)
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		.word	0x92e10000 >> 14	@ stm.w sp, ()
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#endif
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