Re: [PATCH v2] kbuild: add dtbs_prepare target

[Nicolas Schier <nicolas@fjasle.eu>]

On Sun, Jul 24, 2022 at 06:59:19PM +0900, Masahiro Yamada wrote:
> Date:   Sun, 24 Jul 2022 18:59:19 +0900
> From: Masahiro Yamada <masahiroy@kernel.org>
> To: linux-kbuild@vger.kernel.org
> Cc: Nicolas Schier <nicolas@fjasle.eu>, Masahiro Yamada
>  <masahiroy@kernel.org>, Michal Marek <michal.lkml@markovi.net>, Nick
>  Desaulniers <ndesaulniers@google.com>, linux-kernel@vger.kernel.org
> Subject: [PATCH v2] kbuild: add dtbs_prepare target
> Message-Id: <20220724095919.436126-1-masahiroy@kernel.org>
> X-Mailer: git-send-email 2.34.1
> List-ID: <linux-kbuild.vger.kernel.org>
> X-Mailing-List: linux-kbuild@vger.kernel.org
> 
> Factor out the common prerequisites for DT compilation into the new
> target, dtbs_prepare.
> 
> Add comments to explain why include/config/kernel.release is the
> prerequisite. Our policy is that installation targets must not rebuild
> anything in the tree. If 'make modules_install' is executed as root,
> include/config/kernel.release may be owned by root.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---

Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

> 
> Changes for v2:
>  - rephase the comment more concise
> 
>  Makefile | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index dee707c98bbe..a2a030f41e65 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1370,16 +1370,21 @@ endif
>  
>  ifneq ($(dtstree),)
>  
> -%.dtb: include/config/kernel.release scripts_dtc
> +%.dtb: dtbs_prepare
>  	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
>  
> -%.dtbo: include/config/kernel.release scripts_dtc
> +%.dtbo: dtbs_prepare
>  	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
>  
> -PHONY += dtbs dtbs_install dtbs_check
> -dtbs: include/config/kernel.release scripts_dtc
> +PHONY += dtbs dtbs_prepare dtbs_install dtbs_check
> +dtbs: dtbs_prepare
>  	$(Q)$(MAKE) $(build)=$(dtstree)
>  
> +# include/config/kernel.release is actually needed when installing DTBs because
> +# INSTALL_DTBS_PATH contains $(KERNELRELEASE). However, we do not want to make
> +# dtbs_install depend on it as dtbs_install may run as root.
> +dtbs_prepare: include/config/kernel.release scripts_dtc
> +
>  ifneq ($(filter dtbs_check, $(MAKECMDGOALS)),)
>  export CHECK_DTBS=y
>  dtbs: dt_binding_check
> -- 
> 2.34.1

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