From mboxrd@z Thu Jan 1 00:00:00 1970 From: mcoquelin.stm32@gmail.com (Maxime Coquelin) Date: Mon, 25 May 2015 08:37:00 +0200 Subject: [PATCH v2] ARM: nommu: avoid deprecated source register on mov In-Reply-To: <1432337148-9894-1-git-send-email-stefan@agner.ch> References: <1432337148-9894-1-git-send-email-stefan@agner.ch> Message-ID: <5562C30C.20900@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > Signed-off-by: Stefan Agner > --- > 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 Thanks! Maxime