kbuild: suppress warnings for single builds of vmlinux.lds, *.a, etc.

[PATCH] kbuild: suppress warnings for single builds of vmlinux.lds, *.a, etc.

Posted by Masahiro Yamada 3 years, 6 months ago

vmlinux-deps is unneeded because the dependency can directly list
$(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)

Do not cancel the rule; building an individual vmlinux.lds, built-in.a,
or lib.a is working now, but the warning "overriding recipe for target"
is shown.

Without this patch:

  $ make arch/x86/kernel/vmlinux.lds
  Makefile:1798: warning: overriding recipe for target 'arch/x86/kernel/vmlinux.lds'
  Makefile:1162: warning: ignoring old recipe for target 'arch/x86/kernel/vmlinux.lds'
    [ snip ]
    LDS     arch/x86/kernel/vmlinux.lds

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 244c07f1cc70..3e6974b4ebf2 100644
--- a/Makefile
+++ b/Makefile
@@ -1118,7 +1118,8 @@ endif
 export KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LIBS
 export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
 
-vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)
+# The actual objects are generated when descending.
+$(sort $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)): .
 
 # Recurse until adjust_autoksyms.sh is satisfied
 PHONY += autoksyms_recursive
@@ -1157,10 +1158,6 @@ vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
 
 targets := vmlinux
 
-# The actual objects are generated when descending,
-# make sure no implicit rule kicks in
-$(sort $(vmlinux-deps)): . ;
-
 filechk_kernel.release = \
 	echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
 
-- 
2.34.1

Re: [PATCH] kbuild: suppress warnings for single builds of vmlinux.lds, *.a, etc.

Posted by Masahiro Yamada 3 years, 6 months ago

On Mon, Sep 26, 2022 at 10:27 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> vmlinux-deps is unneeded because the dependency can directly list
> $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)
>
> Do not cancel the rule; building an individual vmlinux.lds, built-in.a,
> or lib.a is working now, but the warning "overriding recipe for target"
> is shown.
>
> Without this patch:
>
>   $ make arch/x86/kernel/vmlinux.lds
>   Makefile:1798: warning: overriding recipe for target 'arch/x86/kernel/vmlinux.lds'
>   Makefile:1162: warning: ignoring old recipe for target 'arch/x86/kernel/vmlinux.lds'
>     [ snip ]
>     LDS     arch/x86/kernel/vmlinux.lds
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---


I take this back.


After testing this, I noticed vmlinux was not correctly rebuilt.





>
>  Makefile | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 244c07f1cc70..3e6974b4ebf2 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1118,7 +1118,8 @@ endif
>  export KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LIBS
>  export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
>
> -vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)
> +# The actual objects are generated when descending.
> +$(sort $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)): .
>
>  # Recurse until adjust_autoksyms.sh is satisfied
>  PHONY += autoksyms_recursive
> @@ -1157,10 +1158,6 @@ vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
>
>  targets := vmlinux
>
> -# The actual objects are generated when descending,
> -# make sure no implicit rule kicks in
> -$(sort $(vmlinux-deps)): . ;
> -
>  filechk_kernel.release = \
>         echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
>
> --
> 2.34.1
>


-- 
Best Regards
Masahiro Yamada