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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/arm/kernel/debug.S
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/* SPDX-License-Identifier: GPL-2.0-only */

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/*

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 *  linux/arch/arm/kernel/debug.S

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 *

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 *  Copyright (C) 1994-1999 Russell King

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 *

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 *  32-bit debugging code

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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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/*

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 * Some debugging routines (useful if you've got MM problems and

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 * printk isn't working).  For DEBUGGING ONLY!!!  Do not leave

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 * references to these in a production kernel!

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 */

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#if !defined(CONFIG_DEBUG_SEMIHOSTING)

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#include CONFIG_DEBUG_LL_INCLUDE

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#endif

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#ifdef CONFIG_MMU

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		.macro	addruart_current, rx, tmp1, tmp2

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		addruart	\tmp1, \tmp2, \rx

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		mrc		p15, 0, \rx, c1, c0

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		tst		\rx, #1

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		moveq		\rx, \tmp1

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		movne		\rx, \tmp2

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		.endm

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#else /* !CONFIG_MMU */

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		.macro	addruart_current, rx, tmp1, tmp2

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		addruart	\rx, \tmp1, \tmp2

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		.endm

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#endif /* CONFIG_MMU */

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/*

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 * Useful debugging routines

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 */

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ENTRY(printhex8)

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		mov	r1, #8

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		b	printhex

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ENDPROC(printhex8)

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ENTRY(printhex4)

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		mov	r1, #4

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		b	printhex

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ENDPROC(printhex4)

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ENTRY(printhex2)

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		mov	r1, #2

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printhex:	adr	r2, hexbuf_rel

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		ldr	r3, [r2]

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		add	r2, r2, r3

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		add	r3, r2, r1

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		mov	r1, #0

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		strb	r1, [r3]

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1:		and	r1, r0, #15

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		mov	r0, r0, lsr #4

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		cmp	r1, #10

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		addlt	r1, r1, #'0'

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		addge	r1, r1, #'a' - 10

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		strb	r1, [r3, #-1]!

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		teq	r3, r2

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		bne	1b

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		mov	r0, r2

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		b	printascii

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ENDPROC(printhex2)

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		.pushsection .bss

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hexbuf_addr:	.space 16

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		.popsection

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		.align

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hexbuf_rel:	.long	hexbuf_addr - .

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		.ltorg

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#ifndef CONFIG_DEBUG_SEMIHOSTING

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ENTRY(printascii)

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		addruart_current r3, r1, r2

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1:		teq	r0, #0

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		ldrbne	r1, [r0], #1

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		teqne	r1, #0

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		reteq	lr

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2:		teq     r1, #'\n'

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		bne	3f

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		mov	r1, #'\r'

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#ifdef CONFIG_DEBUG_UART_FLOW_CONTROL

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		waituartcts r2, r3

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#endif

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		waituarttxrdy r2, r3

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		senduart r1, r3

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		busyuart r2, r3

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		mov	r1, #'\n'

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3:

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#ifdef CONFIG_DEBUG_UART_FLOW_CONTROL

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		waituartcts r2, r3

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#endif

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		waituarttxrdy r2, r3

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		senduart r1, r3

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		busyuart r2, r3

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		b	1b

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ENDPROC(printascii)

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ENTRY(printch)

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		addruart_current r3, r1, r2

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		mov	r1, r0

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		mov	r0, #0

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		b	2b

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ENDPROC(printch)

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#ifdef CONFIG_MMU

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ENTRY(debug_ll_addr)

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		addruart r2, r3, ip

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		str	r2, [r0]

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		str	r3, [r1]

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		ret	lr

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ENDPROC(debug_ll_addr)

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#endif

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#else

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ENTRY(printascii)

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		mov	r1, r0

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		mov	r0, #0x04		@ SYS_WRITE0

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	ARM(	svc	#0x123456	)

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#ifdef CONFIG_CPU_V7M

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	THUMB(	bkpt	#0xab		)

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#else

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	THUMB(	svc	#0xab		)

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#endif

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		ret	lr

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ENDPROC(printascii)

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ENTRY(printch)

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		adr	r1, hexbuf_rel

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		ldr	r2, [r1]

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		add	r1, r1, r2

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		strb	r0, [r1]

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		mov	r0, #0x03		@ SYS_WRITEC

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	ARM(	svc	#0x123456	)

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#ifdef CONFIG_CPU_V7M

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	THUMB(	bkpt	#0xab		)

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#else

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	THUMB(	svc	#0xab		)

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#endif

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		ret	lr

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ENDPROC(printch)

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ENTRY(debug_ll_addr)

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		mov	r2, #0

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		str	r2, [r0]

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		str	r2, [r1]

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		ret	lr

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ENDPROC(debug_ll_addr)

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#endif

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