[PATCH RFC next 03/18] scripts/Makefile.extrawarn: migrate -Wvla to a U-Boot-specific file

[Ilias Apalodimas]

On Mon, 4 May 2026 at 16:20, Quentin Schulz <foss+uboot at 0leil.net> wrote:
>
> From: Quentin Schulz <quentin.schulz at cherry.de>
>
> In the next commits, we'll be synchronizing scripts/Makefile.extrawarn
> with the Linux kernel's at version 6.1 which is what we've been claiming
> we've synced to for a while but that isn't true.
>
> In kernel commit 0bb95f80a38f ("Makefile: Globally enable VLA warning"),
> available in v4.20, -Wvla is now enabled tree-wide and not present in
> scripts/Makefile.extrawarn anymore. When we'll be syncing to v6.1, we'll
> therefore be losing this flag (since it's not in our root Makefile). We
> could backport the changes to the root Makefile to our root Makefile but
> U-Boot is not VLA-free unlike the kernel.
>
> We have two options:
> - backport the changes to the root Makefile and disable it in
>   scripts/Makefile.extrawarn.u-boot,
> - only enable it in scripts/Makefile.extrawarn.u-boot, with the same
>   warn level as currently: 3,
>
> For now, do the second option. We should probably go for the first
> option in the long term and try to synchronize our flags with the
> kernel's. Much bigger undertaking than desired right now.
>
> Signed-off-by: Quentin Schulz <quentin.schulz at cherry.de>
> ---

Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>

>  Makefile                          | 1 +
>  scripts/Makefile.extrawarn        | 1 -
>  scripts/Makefile.extrawarn.u-boot | 9 +++++++++
>  3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 49d9740327e..eb61df70838 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1025,6 +1025,7 @@ KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
>  KBUILD_CFLAGS   += $(call cc-option,-Werror=date-time)
>
>  include $(srctree)/scripts/Makefile.extrawarn
> +include $(srctree)/scripts/Makefile.extrawarn.u-boot
>
>  # Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
>  KBUILD_CPPFLAGS += $(KCPPFLAGS)
> diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
> index 4e1714c9484..c5ed501d374 100644
> --- a/scripts/Makefile.extrawarn
> +++ b/scripts/Makefile.extrawarn
> @@ -65,7 +65,6 @@ warning-3 += -Wpointer-arith
>  warning-3 += -Wredundant-decls
>  warning-3 += -Wswitch-default
>  warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
> -warning-3 += $(call cc-option, -Wvla)
>
>  warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
>  warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
> diff --git a/scripts/Makefile.extrawarn.u-boot b/scripts/Makefile.extrawarn.u-boot
> new file mode 100644
> index 00000000000..21872a5492b
> --- /dev/null
> +++ b/scripts/Makefile.extrawarn.u-boot
> @@ -0,0 +1,9 @@
> +# SPDX-License-Identifier: GPL-2.0
> +# ==========================================================================
> +#
> +# Collection of warnings that are specific to U-Boot
> +#
> +# ==========================================================================
> +ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),)
> +KBUILD_CFLAGS += $(call cc-option, -Wvla)
> +endif
>
> --
> 2.54.0
>