[PATCH] ARM: simplify the build rule of mach-types.h

[PATCH] ARM: simplify the build rule of mach-types.h

[Masahiro Yamada]

The directory of mach-types.h is created a couple of lines above:

  _dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)') \

The 'mkdir -p' command is redundant.

scripts/Kbuild.include defines real-prereqs as a shorthand for
$(filter-out $(PHONY),$^). Let's use it to simplify the code.

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

 arch/arm/tools/Makefile | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm/tools/Makefile b/arch/arm/tools/Makefile
index 87de1f63f649..057639019059 100644
--- a/arch/arm/tools/Makefile
+++ b/arch/arm/tools/Makefile
@@ -33,8 +33,7 @@ _dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)') \
           $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')
 
 quiet_cmd_gen_mach = GEN     $@
-      cmd_gen_mach = mkdir -p $(dir $@) && \
-		     $(AWK) -f $(filter-out $(PHONY),$^) > $@
+      cmd_gen_mach = $(AWK) -f $(real-prereqs) > $@
 
 $(kapi)/mach-types.h: $(src)/gen-mach-types $(src)/mach-types FORCE
 	$(call if_changed,gen_mach)
-- 
2.27.0


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RE: [PATCH] ARM: simplify the build rule of mach-types.h

[David Laight]

From: Masahiro Yamada
> Sent: 28 May 2021 04:49
> 
> The directory of mach-types.h is created a couple of lines above:
> 
>   _dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)') \
> 
> The 'mkdir -p' command is redundant.
(In the rule itself)
...
>  quiet_cmd_gen_mach = GEN     $@
> -      cmd_gen_mach = mkdir -p $(dir $@) && \
> -		     $(AWK) -f $(filter-out $(PHONY),$^) > $@
> +      cmd_gen_mach = $(AWK) -f $(real-prereqs) > $@

There is a much easier way to get directories created.
gmake lets you define dependencies that only need to exist
(ie there file timestamps are't checked)
These are ideal for creating directories.

So if can define:

%/.:
	mkdir -p $@

You can just use

$(OBJ)/$(FILE): | ${OBJ)/.

to get any directories created.

Annoyingly gmake doesn't seem to support the 'dynamic dependencies'
of SYSV make (it's only useful feature).
So you can't use:
xxxxx: | $$@D/.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


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[PATCH] ARM: simplify the build rule of mach-types.h

[Masahiro Yamada]

The directory of mach-types.h is created a couple of lines above:

  _dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)') \

The 'mkdir -p' command is redundant.

scripts/Kbuild.include defines real-prereqs as a shorthand for
$(filter-out $(PHONY),$^). Let's use it to simplify the code.

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

KernelVersion: v5.13-rc1

 arch/arm/tools/Makefile | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm/tools/Makefile b/arch/arm/tools/Makefile
index 87de1f63f649..057639019059 100644
--- a/arch/arm/tools/Makefile
+++ b/arch/arm/tools/Makefile
@@ -33,8 +33,7 @@ _dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)') \
           $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')
 
 quiet_cmd_gen_mach = GEN     $@
-      cmd_gen_mach = mkdir -p $(dir $@) && \
-		     $(AWK) -f $(filter-out $(PHONY),$^) > $@
+      cmd_gen_mach = $(AWK) -f $(real-prereqs) > $@
 
 $(kapi)/mach-types.h: $(src)/gen-mach-types $(src)/mach-types FORCE
 	$(call if_changed,gen_mach)
-- 
2.27.0


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Re: [PATCH] ARM: simplify the build rule of mach-types.h

[Linus Walleij]

On Fri, May 28, 2021 at 5:52 AM Masahiro Yamada <masahiroy@kernel.org> wrote:

> The directory of mach-types.h is created a couple of lines above:
>
>   _dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)') \
>
> The 'mkdir -p' command is redundant.
>
> scripts/Kbuild.include defines real-prereqs as a shorthand for
> $(filter-out $(PHONY),$^). Let's use it to simplify the code.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Can you put this into Russell's patch tracker or shall I sign
it off and put it there?

Yours,
Linus Walleij

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Re: [PATCH] ARM: simplify the build rule of mach-types.h

[Masahiro Yamada]

On Fri, May 28, 2021 at 5:24 PM Linus Walleij <linus.walleij@linaro.org> wrote:
>
> On Fri, May 28, 2021 at 5:52 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> > The directory of mach-types.h is created a couple of lines above:
> >
> >   _dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)') \
> >
> > The 'mkdir -p' command is redundant.
> >
> > scripts/Kbuild.include defines real-prereqs as a shorthand for
> > $(filter-out $(PHONY),$^). Let's use it to simplify the code.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
>
> Can you put this into Russell's patch tracker or shall I sign
> it off and put it there?


I sent this to patches@arm.linux.org.uk

It is already there.
https://www.arm.linux.org.uk/developer/patches/section.php?section=0



-- 
Best Regards
Masahiro Yamada

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