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From: mcoquelin.stm32@gmail.com (Maxime Coquelin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] ARM: nommu: avoid deprecated source register on mov
Date: Mon, 25 May 2015 08:37:00 +0200	[thread overview]
Message-ID: <5562C30C.20900@gmail.com> (raw)
In-Reply-To: <1432337148-9894-1-git-send-email-stefan@agner.ch>

Hi Stefan,

On 05/23/2015 01:25 AM, Stefan Agner wrote:
> In Thumb2 mode, the stack register r13 is deprecated if the
> destination register is the program counter (r15). Similar to
> head.S, head-nommu.S uses r13 to store the return address used
> after configuring the CPU's CP15 register. However, since we do
> not enable a MMU, there will be no address switch and it is
> possible to use branch with link instruction to call
> __after_proc_init.
>
> Avoid using r13 completely by using bl to call __after_proc_init
> and get rid of __secondary_switched.
>
> Beside removing unnecessary complexity, this also fixes a
> compiler warning when compiling a !MMU kernel:
> Warning: Use of r13 as a source register is deprecated when r15
> is the destination register.
>
> Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> Changes in v2:
> - Load r7 outside CONFIG_ARM_MPU since its used outside later on
>
>   arch/arm/kernel/head-nommu.S | 21 ++++++++-------------
>   1 file changed, 8 insertions(+), 13 deletions(-)
>
>

You can add my:
Tested-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>

Thanks!
Maxime

WARNING: multiple messages have this Message-ID (diff)
From: Maxime Coquelin <mcoquelin.stm32@gmail.com>
To: Stefan Agner <stefan@agner.ch>, linux@arm.linux.org.uk
Cc: arnd@arndb.de, will.deacon@arm.com,
	u.kleine-koenig@pengutronix.de, manabian@gmail.com,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] ARM: nommu: avoid deprecated source register on mov
Date: Mon, 25 May 2015 08:37:00 +0200	[thread overview]
Message-ID: <5562C30C.20900@gmail.com> (raw)
In-Reply-To: <1432337148-9894-1-git-send-email-stefan@agner.ch>

Hi Stefan,

On 05/23/2015 01:25 AM, Stefan Agner wrote:
> In Thumb2 mode, the stack register r13 is deprecated if the
> destination register is the program counter (r15). Similar to
> head.S, head-nommu.S uses r13 to store the return address used
> after configuring the CPU's CP15 register. However, since we do
> not enable a MMU, there will be no address switch and it is
> possible to use branch with link instruction to call
> __after_proc_init.
>
> Avoid using r13 completely by using bl to call __after_proc_init
> and get rid of __secondary_switched.
>
> Beside removing unnecessary complexity, this also fixes a
> compiler warning when compiling a !MMU kernel:
> Warning: Use of r13 as a source register is deprecated when r15
> is the destination register.
>
> Suggested-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> Changes in v2:
> - Load r7 outside CONFIG_ARM_MPU since its used outside later on
>
>   arch/arm/kernel/head-nommu.S | 21 ++++++++-------------
>   1 file changed, 8 insertions(+), 13 deletions(-)
>
>

You can add my:
Tested-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>

Thanks!
Maxime

  reply	other threads:[~2015-05-25  6:37 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-22 23:25 [PATCH v2] ARM: nommu: avoid deprecated source register on mov Stefan Agner
2015-05-22 23:25 ` Stefan Agner
2015-05-25  6:37 ` Maxime Coquelin [this message]
2015-05-25  6:37   ` Maxime Coquelin
2015-06-02 19:42 ` Stefan Agner
2015-06-02 19:42   ` Stefan Agner

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