All of lore.kernel.org
 help / color / mirror / Atom feed
From: Gregory CLEMENT <gregory.clement@free-electrons.com>
To: Russell King <rmk+kernel@arm.linux.org.uk>,
	linux-arm-kernel@lists.infradead.org
Cc: Andrew Lunn <andrew@lunn.ch>,
	kvm@vger.kernel.org, linux-sh@vger.kernel.org,
	Kevin Hilman <khilman@deeprootsystems.com>,
	Sekhar Nori <nsekhar@ti.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	kvmarm@lists.cs.columbia.edu, linux-samsung-soc@vger.kernel.org,
	Kukjin Kim <kgene.kim@samsung.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	Magnus Damm <magnus.damm@gmail.com>,
	Gleb Natapov <gleb@kernel.org>, Tony Lindgren <tony@atomide.com>,
	xen-devel@lists.xenproject.org,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
	Jason Cooper <jason@lakedaemon.net>,
	Stephen Warren <swarren@wwwdotorg.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Hans Ulli Kroll <ulli.kroll@googlemail.com>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Simon Horman <horms@verge.net.au>,
	Ben Dooks <ben-linux@fluff.org>, linux-tegra@vger.kernel.org,
Subject: Re: [PATCH] ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+
Date: Wed, 02 Jul 2014 11:24:28 +0200	[thread overview]
Message-ID: <53B3CFCC.50506@free-electrons.com> (raw)
In-Reply-To: <E1X20Rs-00082S-KI@rmk-PC.arm.linux.org.uk>

Hi Russell,

On 01/07/2014 17:58, Russell King wrote:
> ARMv6 and greater introduced a new instruction ("bx") which can be used
> to return from function calls.  Recent CPUs perform better when the
> "bx lr" instruction is used rather than the "mov pc, lr" instruction,
> and this sequence is strongly recommended to be used by the ARM
> architecture manual (section A.4.1.1).
> 
> We provide a new macro "ret" with all its variants for the condition
> code which will resolve to the appropriate instruction.
> 
> Rather than doing this piecemeal, and miss some instances, change all
> the "mov pc" instances to use the new macro, with the exception of
> the "movs" instruction and the kprobes code.  This allows us to detect
> the "mov pc, lr" case and fix it up - and also gives us the possibility
> of deploying this for other registers depending on the CPU selection.
> 
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

It booted on Armada XP, Armada 370, Armada 385 and Armada 375

Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

Thanks,

Gregory


> ---


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

WARNING: multiple messages have this Message-ID (diff)
From: Gregory CLEMENT <gregory.clement@free-electrons.com>
To: Russell King <rmk+kernel@arm.linux.org.uk>,
	linux-arm-kernel@lists.infradead.org
Cc: Andrew Lunn <andrew@lunn.ch>,
	kvm@vger.kernel.org, linux-sh@vger.kernel.org,
	Kevin Hilman <khilman@deeprootsystems.com>,
	Sekhar Nori <nsekhar@ti.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	kvmarm@lists.cs.columbia.edu, linux-samsung-soc@vger.kernel.org,
	Kukjin Kim <kgene.kim@samsung.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	Magnus Damm <magnus.damm@gmail.com>,
	Gleb Natapov <gleb@kernel.org>, Tony Lindgren <tony@atomide.com>,
	xen-devel@lists.xenproject.org,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
	Jason Cooper <jason@lakedaemon.net>,
	Stephen Warren <swarren@wwwdotorg.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Hans Ulli Kroll <ulli.kroll@googlemail.com>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Simon Horman <horms@verge.net.au>,
	Ben Dooks <ben-linux@fluff.org>,
	linux-tegra@vger.kernel.org
Subject: Re: [PATCH] ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+
Date: Wed, 02 Jul 2014 11:24:28 +0200	[thread overview]
Message-ID: <53B3CFCC.50506@free-electrons.com> (raw)
In-Reply-To: <E1X20Rs-00082S-KI@rmk-PC.arm.linux.org.uk>

Hi Russell,

On 01/07/2014 17:58, Russell King wrote:
> ARMv6 and greater introduced a new instruction ("bx") which can be used
> to return from function calls.  Recent CPUs perform better when the
> "bx lr" instruction is used rather than the "mov pc, lr" instruction,
> and this sequence is strongly recommended to be used by the ARM
> architecture manual (section A.4.1.1).
> 
> We provide a new macro "ret" with all its variants for the condition
> code which will resolve to the appropriate instruction.
> 
> Rather than doing this piecemeal, and miss some instances, change all
> the "mov pc" instances to use the new macro, with the exception of
> the "movs" instruction and the kprobes code.  This allows us to detect
> the "mov pc, lr" case and fix it up - and also gives us the possibility
> of deploying this for other registers depending on the CPU selection.
> 
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

It booted on Armada XP, Armada 370, Armada 385 and Armada 375

Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

Thanks,

Gregory


> ---


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

WARNING: multiple messages have this Message-ID (diff)
From: gregory.clement@free-electrons.com (Gregory CLEMENT)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+
Date: Wed, 02 Jul 2014 11:24:28 +0200	[thread overview]
Message-ID: <53B3CFCC.50506@free-electrons.com> (raw)
In-Reply-To: <E1X20Rs-00082S-KI@rmk-PC.arm.linux.org.uk>

Hi Russell,

On 01/07/2014 17:58, Russell King wrote:
> ARMv6 and greater introduced a new instruction ("bx") which can be used
> to return from function calls.  Recent CPUs perform better when the
> "bx lr" instruction is used rather than the "mov pc, lr" instruction,
> and this sequence is strongly recommended to be used by the ARM
> architecture manual (section A.4.1.1).
> 
> We provide a new macro "ret" with all its variants for the condition
> code which will resolve to the appropriate instruction.
> 
> Rather than doing this piecemeal, and miss some instances, change all
> the "mov pc" instances to use the new macro, with the exception of
> the "movs" instruction and the kprobes code.  This allows us to detect
> the "mov pc, lr" case and fix it up - and also gives us the possibility
> of deploying this for other registers depending on the CPU selection.
> 
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

It booted on Armada XP, Armada 370, Armada 385 and Armada 375

Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

Thanks,

Gregory


> ---


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

  parent reply	other threads:[~2014-07-02  9:24 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-01 15:58 [PATCH] ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ Russell King
2014-07-01 15:58 ` Russell King
2014-07-01 17:51 ` Andrew Lunn
2014-07-01 17:51 ` Andrew Lunn
2014-07-01 17:51   ` Andrew Lunn
2014-07-01 17:51   ` Andrew Lunn
2014-07-02  5:10 ` Shawn Guo
2014-07-02  5:10 ` Shawn Guo
2014-07-02  5:10   ` Shawn Guo
2014-07-02  5:10   ` Shawn Guo
2014-07-02  9:02 ` Tony Lindgren
2014-07-02  9:24 ` Gregory CLEMENT
2014-07-02  9:24 ` Gregory CLEMENT [this message]
2014-07-02  9:24   ` Gregory CLEMENT
2014-07-02  9:24   ` Gregory CLEMENT
2014-07-02 11:31 ` Sekhar Nori
2014-07-04 10:11 ` Christoffer Dall
2014-07-04 10:11 ` Christoffer Dall
2014-07-04 10:11   ` Christoffer Dall
2014-07-04 10:11   ` Christoffer Dall
     [not found] ` <E1X20Rs-00082S-KI-eh5Bv4kxaXIANfyc6IWni62ZND6+EDdj@public.gmane.org>
2014-07-02  9:02   ` Tony Lindgren
2014-07-02  9:02     ` Tony Lindgren
2014-07-02  9:02     ` Tony Lindgren
2014-07-02 11:31   ` Sekhar Nori
2014-07-02 11:31     ` Sekhar Nori
2014-07-02 11:31     ` Sekhar Nori
2014-07-04 11:09   ` Haojian Zhuang
2014-07-04 11:09     ` Haojian Zhuang
2014-07-04 11:09     ` Haojian Zhuang
2014-07-04 11:09 ` Haojian Zhuang
2014-07-04 11:27 ` Stefano Stabellini
2014-07-04 11:27   ` Stefano Stabellini
2014-07-04 11:27   ` Stefano Stabellini
2014-07-04 11:27 ` Stefano Stabellini
2014-07-04 14:24 ` Uwe Kleine-König
2014-07-04 14:24   ` Uwe Kleine-König
2014-07-04 14:24   ` Uwe Kleine-König
2014-07-04 14:24 ` Uwe Kleine-König
2014-07-07  9:21 ` Simon Horman
2014-07-07  9:21   ` Simon Horman
2014-07-07  9:21   ` Simon Horman
2014-07-07  9:21 ` Simon Horman
  -- strict thread matches above, loose matches on Subject: below --
2014-07-01 15:58 Russell King
2014-07-01 16:14 Russell King
2014-07-01 16:14 Russell King
2014-07-01 16:14 ` Russell King

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=53B3CFCC.50506@free-electrons.com \
    --to=gregory.clement@free-electrons.com \
    --cc=andrew@lunn.ch \
    --cc=ben-linux@fluff.org \
    --cc=gleb@kernel.org \
    --cc=haojian.zhuang@gmail.com \
    --cc=herbert@gondor.apana.org.au \
    --cc=horms@verge.net.au \
    --cc=jason@lakedaemon.net \
    --cc=kgene.kim@samsung.com \
    --cc=khilman@deeprootsystems.com \
    --cc=kvm@vger.kernel.org \
    --cc=kvmarm@lists.cs.columbia.edu \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=linux-sh@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=magnus.damm@gmail.com \
    --cc=marc.zyngier@arm.com \
    --cc=nsekhar@ti.com \
    --cc=rmk+kernel@arm.linux.org.uk \
    --cc=sebastian.hesselbarth@gmail.com \
    --cc=stefano.stabellini@eu.citrix.com \
    --cc=swarren@wwwdotorg.org \
    --cc=thierry.reding@gmail.com \
    --cc=tony@atomide.com \
    --cc=ulli.kroll@googlemail.com \
    --cc=xen-devel@lists.xenproject.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.