[Buildroot] [PATCH] configs/kontron_pitx_imx8m_defconfig: remove BR2_ARM_FPU_VFPV3

[Buildroot] [PATCH] configs/kontron_pitx_imx8m_defconfig: remove BR2_ARM_FPU_VFPV3

[Heiko Thiery]

The FP setting is not used for aarch64 in buildroot. The FPU options are
set implicit.

Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
---
 configs/kontron_pitx_imx8m_defconfig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/configs/kontron_pitx_imx8m_defconfig b/configs/kontron_pitx_imx8m_defconfig
index 7f9c0eeae8..8f756f5246 100644
--- a/configs/kontron_pitx_imx8m_defconfig
+++ b/configs/kontron_pitx_imx8m_defconfig
@@ -1,6 +1,5 @@
 # Architecture
 BR2_aarch64=y
-BR2_ARM_FPU_VFPV3=y
 
 # System
 BR2_TARGET_GENERIC_GETTY_PORT="ttymxc2"
-- 
2.30.2

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Re: [Buildroot] [PATCH] configs/kontron_pitx_imx8m_defconfig: remove BR2_ARM_FPU_VFPV3

[Thomas Petazzoni]

On Thu, 20 Jan 2022 14:52:52 +0100
Heiko Thiery <heiko.thiery@gmail.com> wrote:

> The FP setting is not used for aarch64 in buildroot. The FPU options are
> set implicit.
> 
> Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
> ---
>  configs/kontron_pitx_imx8m_defconfig | 1 -
>  1 file changed, 1 deletion(-)

Applied to master, thanks. That being said the FPU handling on AArch64
is not very clear to me. I'm not sure we're handling it correctly in
Buildroot today.

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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Re: [Buildroot] [PATCH] configs/kontron_pitx_imx8m_defconfig: remove BR2_ARM_FPU_VFPV3

[Heiko Thiery]

Hi Thomas,

Am Sa., 22. Jan. 2022 um 13:15 Uhr schrieb Thomas Petazzoni
<thomas.petazzoni@bootlin.com>:
>
> On Thu, 20 Jan 2022 14:52:52 +0100
> Heiko Thiery <heiko.thiery@gmail.com> wrote:
>
> > The FP setting is not used for aarch64 in buildroot. The FPU options are
> > set implicit.
> >
> > Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
> > ---
> >  configs/kontron_pitx_imx8m_defconfig | 1 -
> >  1 file changed, 1 deletion(-)
>
> Applied to master, thanks. That being said the FPU handling on AArch64
> is not very clear to me. I'm not sure we're handling it correctly in
> Buildroot today.

I must admit that I have not fully understood the topic FPU either.
What I am sure of is that the kconfig selection of the "Floating point
stategy" option for aarch64 has no effect, since this setting is made
implicitly depending on the target architecture used.


Therefore, a patch could look something like this to fix this:

diff --git a/arch/Config.in.arm b/arch/Config.in.arm
index 4c0910e4f8..05acaa9157 100644
--- a/arch/Config.in.arm
+++ b/arch/Config.in.arm
@@ -618,6 +618,7 @@ endchoice

 choice
        prompt "Floating point strategy"
+      depends on BR2_arm || BR2_armeb
        default BR2_ARM_FPU_FP_ARMV8 if BR2_ARM_CPU_HAS_FP_ARMV8
        default BR2_ARM_FPU_FPV5D16 if BR2_ARM_CPU_HAS_FPV5
        default BR2_ARM_FPU_FPV4D16 if BR2_ARM_CPU_HAS_FPV4


-- 
Heiko
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