From: nicolas.pitre@linaro.org (Nicolas Pitre)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/3] ARM: early_printk: use printascii() rather than printch()
Date: Tue, 31 Oct 2017 13:48:01 -0400 (EDT) [thread overview]
Message-ID: <nycvar.YSQ.7.76.1710311346190.21665@knanqh.ubzr> (raw)
In-Reply-To: <20171031171629.GI9463@n2100.armlinux.org.uk>
On Tue, 31 Oct 2017, Russell King - ARM Linux wrote:
> 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.
Right, missed that.
New patch below:
diff --git a/arch/arm/kernel/debug.S b/arch/arm/kernel/debug.S
index ea9646cc2a..0d1cef4b6e 100644
--- a/arch/arm/kernel/debug.S
+++ b/arch/arm/kernel/debug.S
@@ -79,25 +79,28 @@ hexbuf: .space 16
ENTRY(printascii)
addruart_current r3, r1, r2
- b 2f
-1: waituart r2, r3
- senduart r1, r3
- busyuart r2, r3
- teq r1, #'\n'
- moveq r1, #'\r'
- beq 1b
-2: teq r0, #0
+1: teq r0, #0
ldrneb r1, [r0], #1
teqne r1, #0
- bne 1b
- ret lr
+ 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)
ENTRY(printch)
addruart_current r3, r1, r2
mov r1, r0
mov r0, #0
- b 1b
+ b 2b
ENDPROC(printch)
#ifdef CONFIG_MMU
>
> > 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
> According to speedtest.net: 8.21Mbps down 510kbps up
>
next prev parent reply other threads:[~2017-10-31 17:48 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
2017-10-31 17:48 ` Nicolas Pitre [this message]
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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