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From: linux@armlinux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/3] ARM: early_printk: use printascii() rather than printch()
Date: Tue, 31 Oct 2017 17:16:29 +0000	[thread overview]
Message-ID: <20171031171629.GI9463@n2100.armlinux.org.uk> (raw)
In-Reply-To: <nycvar.YSQ.7.76.1710311302370.21665@knanqh.ubzr>

On Tue, Oct 31, 2017 at 01:06:35PM -0400, Nicolas Pitre wrote:
> That's easy to veryfy with this patch:

Unfortunately not that easy, this patch breaks printch.

> diff --git a/arch/arm/kernel/debug.S b/arch/arm/kernel/debug.S
> index ea9646cc2a..40023a4871 100644
> --- a/arch/arm/kernel/debug.S
> +++ b/arch/arm/kernel/debug.S
> @@ -79,18 +79,21 @@ hexbuf:		.space 16
>  

The new code is:

>  ENTRY(printascii)
>  		addruart_current r3, r1, r2
> +1:		teq	r0, #0
>  		ldrneb	r1, [r0], #1
>  		teqne	r1, #0
> +		reteq	lr
> +		teq     r1, #'\n'
> +		bne	2f
> +		mov	r1, '\r'
> +		waituart r2, r3
> +		senduart r1, r3
> +		busyuart r2, r3
> +		mov	r1, '\n'
> +2:		waituart r2, r3
> +		senduart r1, r3
> +		busyuart r2, r3
> +		b	1b
>  ENDPROC(printascii)

and printch jumps to the 1: label with r0 = 0 and r1 = character.  Your
change has the effect that the "reteq" will always be taken when called
by printch.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
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  reply	other threads:[~2017-10-31 17:16 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-02  2:06 [PATCH 0/3] a few debug_ll fixes and improvements Nicolas Pitre
2017-10-02  2:06 ` [PATCH 1/3] ARM: debug.S: move hexbuf to a writable section Nicolas Pitre
2017-10-02  2:06 ` [PATCH 2/3] ARM: semihosting: use proper instruction on v7m processors Nicolas Pitre
2017-10-02  2:06 ` [PATCH 3/3] ARM: early_printk: use printascii() rather than printch() Nicolas Pitre
2017-10-02  5:20   ` Uwe Kleine-König
2017-10-02 14:09     ` Nicolas Pitre
2017-10-31 11:28   ` Chris Brandt
2017-10-31 16:22     ` Nicolas Pitre
2017-10-31 16:38       ` Robin Murphy
2017-10-31 17:06         ` Nicolas Pitre
2017-10-31 17:16           ` Russell King - ARM Linux [this message]
2017-10-31 17:48             ` Nicolas Pitre
2017-10-31 17:53               ` Russell King - ARM Linux
2017-10-31 18:15                 ` Nicolas Pitre
2017-10-31 18:20                   ` Russell King - ARM Linux
2017-10-31 18:35                     ` Nicolas Pitre
2017-10-31 19:12                       ` Chris Brandt
2017-10-31 19:28                         ` Nicolas Pitre
2017-10-31 21:50                           ` Russell King - ARM Linux
2017-10-31 23:35                             ` Nicolas Pitre
2017-10-31 23:50                               ` Russell King - ARM Linux
2017-11-02  0:09                         ` Russell King - ARM Linux
2017-11-02  3:59                           ` Nicolas Pitre
2017-11-02  4:16                             ` Nicolas Pitre
2017-11-02 11:09                               ` Russell King - ARM Linux
2017-11-02 15:12                                 ` Nicolas Pitre
2017-11-02 11:06                             ` Chris Brandt
2017-11-02 11:20                               ` Russell King - ARM Linux
2017-11-02 11:28                                 ` Chris Brandt
2017-11-02 13:04                                   ` Russell King - ARM Linux
2017-11-02 15:04                                   ` Nicolas Pitre
2017-11-02 15:18                                     ` Robin Murphy
2017-11-02 15:22                                       ` Russell King - ARM Linux
2017-11-02 15:25                                       ` Chris Brandt
2017-11-02 15:23                                     ` Chris Brandt
2017-11-02 15:35                                       ` Nicolas Pitre
2017-11-02 16:06                                         ` Nicolas Pitre
2017-11-02 16:38                                           ` Chris Brandt
2017-11-02 17:10                                             ` Russell King - ARM Linux
2017-11-02 17:20                                               ` Nicolas Pitre
2017-11-02 17:28                                               ` Chris Brandt
2017-11-02 18:29                                               ` Robin Murphy
2017-11-02 21:46                                                 ` syntax unified, was " Nicolas Pitre
2017-11-02 15:48                                       ` Russell King - ARM Linux
2017-11-02 16:30                                         ` Chris Brandt

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