[v2,10/10] ARM: add multi_v7_lpae_defconfig

Commit Message

Alexander Stein Jan. 20, 2023, 1:34 p.m. UTC

From: Nicolas Saenz Julienne <[e-mail]>

The only missing configuration option preventing us from using
multi_v7_defconfig with the Raspberry Pi 4 is ARM_LPAE. It's needed as
the PCIe controller found on the SoC depends on 64bit addressing, yet
can't be included as not all v7 boards support LPAE.

Introduce multi_v7_lpae_defconfig, built off multi_v7_defconfig, which will
avoid us having to duplicate and maintain multiple similar configurations.

Needless to say the Raspberry Pi 4 is not the only platform that can
benefit from this new configuration.

Signed-off-by: Nicolas Saenz Julienne <[e-mail]>
Signed-off-by: Alexander Stein <[e-mail]>
---
Directly applied from https://lore.kernel.org/linux-arm-kernel/[e-mail]/T/#m96968dd45c0aaa88e0a7387024b5ac13b002363d
Although I had to apply manually

 arch/arm/Makefile            | 4 ++++
 arch/arm/configs/lpae.config | 1 +
 2 files changed, 5 insertions(+)
 create mode 100644 arch/arm/configs/lpae.config

Comments

Arnd Bergmann Jan. 20, 2023, 5:18 p.m. UTC | #1

On Fri, Jan 20, 2023, at 14:34, Alexander Stein wrote:
> From: Nicolas Saenz Julienne <[e-mail]>
>
> The only missing configuration option preventing us from using
> multi_v7_defconfig with the Raspberry Pi 4 is ARM_LPAE. It's needed as
> the PCIe controller found on the SoC depends on 64bit addressing, yet
> can't be included as not all v7 boards support LPAE.
>
> Introduce multi_v7_lpae_defconfig, built off multi_v7_defconfig, which will
> avoid us having to duplicate and maintain multiple similar configurations.
>
> Needless to say the Raspberry Pi 4 is not the only platform that can
> benefit from this new configuration.
>
> Signed-off-by: Nicolas Saenz Julienne <[e-mail]>
> Signed-off-by: Alexander Stein <[e-mail]>

This is ok in principle, two minor points though:

> +include $(srctree)/scripts/Makefile.defconf
> +PHONY += multi_v7_lpae_defconfig
> +multi_v7_lpae_defconfig:
> +	$(call merge_into_defconfig,multi_v7_defconfig,lpae)
> 
>  define archhelp
>    echo  '* zImage        - Compressed kernel image (arch/$(ARCH)/boot/zImage)'

The new target does not get listed in 'make help' as far as I can
tell, can you add it there in the process?

> diff --git a/arch/arm/configs/lpae.config b/arch/arm/configs/lpae.config
> new file mode 100644
> index 0000000000000..19bab134e014b
> --- /dev/null
> +++ b/arch/arm/configs/lpae.config
> @@ -0,0 +1 @@
> +CONFIG_ARM_LPAE=y

My feeling is that we probably want CONFIG_VMSPLIT_2G=y here
as well, given that a lot of the systems that want LPAE
will have a lot of memory, and are limited by the amount
of lowmem even when CONFIG_HIGHMEM is enabled.

Can you make sure that this works on your machine, and
include this option?

     Arnd

Patch

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 506dbc72323bc..80d9eaf3dc06a 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -314,6 +314,10 @@  endif
 # My testing targets (bypasses dependencies)
 bp:;	$(Q)$(MAKE) $(build)=$(boot) $(boot)/bootpImage
 
+include $(srctree)/scripts/Makefile.defconf
+PHONY += multi_v7_lpae_defconfig
+multi_v7_lpae_defconfig:
+	$(call merge_into_defconfig,multi_v7_defconfig,lpae)
 
 define archhelp
   echo  '* zImage        - Compressed kernel image (arch/$(ARCH)/boot/zImage)'
diff --git a/arch/arm/configs/lpae.config b/arch/arm/configs/lpae.config
new file mode 100644
index 0000000000000..19bab134e014b
--- /dev/null
+++ b/arch/arm/configs/lpae.config
@@ -0,0 +1 @@ 
+CONFIG_ARM_LPAE=y