[Buildroot] [PATCH 02/15] board/qemu/ppc*: disable Werror while building ppc kernel with gcc >= 9.1

[Yann E. MORIN <yann.morin.1998@free.fr>]

Romain, All,

On 2019-05-06 20:29 +0200, Romain Naour spake thusly:
> From patch [1] included in kernel >= 5.0:
> "The upcoming GCC 9 release extends the -Wmissing-attributes warnings
> (enabled by -Wall) to C and aliases: it warns when particular function
> attributes are missing in the aliases but not in their target.
> 
> In particular, it triggers for all the init/cleanup_module
> aliases in the kernel (defined by the module_init/exit macros),
> ending up being very noisy.
> 
> These aliases point to the __init/__exit functions of a module,
> which are defined as __cold (among other attributes). However,
> the aliases themselves do not have the __cold attribute.
> 
> Since the compiler behaves differently when compiling a __cold
> function as well as when compiling paths leading to calls
> to __cold functions, the warning is trying to point out
> the possibly-forgotten attribute in the alias."
> 
> Werror is set by default while building ppc kernel [2], but
> some warning can be introduced while building current kernel with
> newer compiler (for example building kernel 4.19 with gcc 9.1).
> 
> Instead of backporting this patch [1] to kernel 4.19, select
> the Kconfig option CONFIG_PPC_DISABLE_WERROR that allow to
> disable Werror.
> 
> Add CONFIG_PPC_DISABLE_WERROR only for qemu ppc{64} defconfig
> since they are used for CI with toolchain-builder's gitlab [3].

When you introduce gcc-9 later in the series, itis not the default
compiler, so it will not be selected for these defconfigs.

So, I don't think we need this change (yet).

If we decide to update these defconfigs to use the latest gcc-9, later,
then that would be the moment to include the fix.

Regards,
Yann E. MORIN.

> Fixes:
> https://gitlab.com/kubu93/toolchains-builder/-/jobs/205435741
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=a6e60d84989fa0e91db7f236eda40453b0e44afa
> [2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=ba55bd74360ea4b8b95e73ed79474d37ff482b36
> [3] https://gitlab.com/bootlin/toolchains-builder
> 
> Signed-off-by: Romain Naour <romain.naour@gmail.com>
> ---
> Note: It can be usefull to select CONFIG_PPC_DISABLE_WERROR for
> other ppc board defconfig.
> 
> v2: add a shared fragment in board/fragments/linux and update
> qemu ppc* defconfigs. (Arnout)
> ---
>  board/fragments/linux/linux-ppc-disable-werror.fragment | 1 +
>  configs/qemu_ppc64_e5500_defconfig                      | 2 +-
>  configs/qemu_ppc64_pseries_defconfig                    | 1 +
>  configs/qemu_ppc64le_pseries_defconfig                  | 1 +
>  configs/qemu_ppc_g3beige_defconfig                      | 1 +
>  configs/qemu_ppc_mpc8544ds_defconfig                    | 1 +
>  configs/qemu_ppc_virtex_ml507_defconfig                 | 1 +
>  7 files changed, 7 insertions(+), 1 deletion(-)
>  create mode 100644 board/fragments/linux/linux-ppc-disable-werror.fragment
> 
> diff --git a/board/fragments/linux/linux-ppc-disable-werror.fragment b/board/fragments/linux/linux-ppc-disable-werror.fragment
> new file mode 100644
> index 0000000000..6ea12a1243
> --- /dev/null
> +++ b/board/fragments/linux/linux-ppc-disable-werror.fragment
> @@ -0,0 +1 @@
> +CONFIG_PPC_DISABLE_WERROR=y
> diff --git a/configs/qemu_ppc64_e5500_defconfig b/configs/qemu_ppc64_e5500_defconfig
> index 59b8636918..624155316c 100644
> --- a/configs/qemu_ppc64_e5500_defconfig
> +++ b/configs/qemu_ppc64_e5500_defconfig
> @@ -13,7 +13,7 @@ BR2_LINUX_KERNEL=y
>  BR2_LINUX_KERNEL_CUSTOM_VERSION=y
>  BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.16"
>  BR2_LINUX_KERNEL_DEFCONFIG="corenet64_smp"
> -BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="board/qemu/ppc64-e5500/linux.fragment"
> +BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="board/qemu/ppc64-e5500/linux.fragment board/fragments/linux/linux-ppc-disable-werror.fragment"
>  BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
>  
>  # Filesystem
> diff --git a/configs/qemu_ppc64_pseries_defconfig b/configs/qemu_ppc64_pseries_defconfig
> index 5f55b246f7..277d08989a 100644
> --- a/configs/qemu_ppc64_pseries_defconfig
> +++ b/configs/qemu_ppc64_pseries_defconfig
> @@ -19,3 +19,4 @@ BR2_LINUX_KERNEL_CUSTOM_VERSION=y
>  BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.16"
>  BR2_LINUX_KERNEL_DEFCONFIG="pseries"
>  BR2_LINUX_KERNEL_VMLINUX=y
> +BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="board/fragments/linux/linux-ppc-disable-werror.fragment"
> diff --git a/configs/qemu_ppc64le_pseries_defconfig b/configs/qemu_ppc64le_pseries_defconfig
> index 8356e4e250..1848667abf 100644
> --- a/configs/qemu_ppc64le_pseries_defconfig
> +++ b/configs/qemu_ppc64le_pseries_defconfig
> @@ -19,3 +19,4 @@ BR2_LINUX_KERNEL_CUSTOM_VERSION=y
>  BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.16"
>  BR2_LINUX_KERNEL_DEFCONFIG="pseries_le"
>  BR2_LINUX_KERNEL_VMLINUX=y
> +BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="board/fragments/linux/linux-ppc-disable-werror.fragment"
> diff --git a/configs/qemu_ppc_g3beige_defconfig b/configs/qemu_ppc_g3beige_defconfig
> index 4b2f3ed2fe..c8bbd74ada 100644
> --- a/configs/qemu_ppc_g3beige_defconfig
> +++ b/configs/qemu_ppc_g3beige_defconfig
> @@ -18,6 +18,7 @@ BR2_LINUX_KERNEL_CUSTOM_VERSION=y
>  BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.16"
>  BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
>  BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/ppc-g3beige/linux.config"
> +BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="board/fragments/linux/linux-ppc-disable-werror.fragment"
>  BR2_LINUX_KERNEL_VMLINUX=y
>  
>  # Serial port config
> diff --git a/configs/qemu_ppc_mpc8544ds_defconfig b/configs/qemu_ppc_mpc8544ds_defconfig
> index 98985b7b76..68a9e80e93 100644
> --- a/configs/qemu_ppc_mpc8544ds_defconfig
> +++ b/configs/qemu_ppc_mpc8544ds_defconfig
> @@ -18,6 +18,7 @@ BR2_LINUX_KERNEL_CUSTOM_VERSION=y
>  BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.16"
>  BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
>  BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/ppc-mpc8544ds/linux.config"
> +BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="board/fragments/linux/linux-ppc-disable-werror.fragment"
>  BR2_LINUX_KERNEL_VMLINUX=y
>  
>  # Serial port config
> diff --git a/configs/qemu_ppc_virtex_ml507_defconfig b/configs/qemu_ppc_virtex_ml507_defconfig
> index eddaf3558a..2a127ed70d 100644
> --- a/configs/qemu_ppc_virtex_ml507_defconfig
> +++ b/configs/qemu_ppc_virtex_ml507_defconfig
> @@ -18,6 +18,7 @@ BR2_LINUX_KERNEL_CUSTOM_VERSION=y
>  BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.16"
>  BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
>  BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/ppc-virtex-ml507/linux.config"
> +BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="board/fragments/linux/linux-ppc-disable-werror.fragment"
>  BR2_LINUX_KERNEL_VMLINUX=y
>  BR2_LINUX_KERNEL_DTS_SUPPORT=y
>  BR2_LINUX_KERNEL_INTREE_DTS_NAME="virtex440-ml507"
> -- 
> 2.14.5
> 
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