[PATCH v2] kbuild: add workaround for Debian make-kpkg

[PATCH v2] kbuild: add workaround for Debian make-kpkg

[Masahiro Yamada]

Since commit 3812b8c5c5d5 ("kbuild: make -r/-R effective in top
Makefile for old Make versions"), make-kpkg is not working.

make-kpkg directly includes the top Makefile of Linux kernel, and
appends some debian_* targets.

  /usr/share/kernel-package/ruleset/kernel_version.mk:

    # Include the kernel makefile
    override dot-config := 1
    include Makefile
    dot-config := 1

I did not know the kernel Makefile was used in that way, and it is
hard to guarantee the behavior when the kernel Makefile is included
by another Makefile from a different project.

It looks like Debian Stretch stopped providing make-kpkg. Maybe it is
obsolete and being replaced with 'make deb-pkg' etc. but still widely
used.

This commit adds a workaround; if the top Makefile is included by
another Makefile, skip sub-make in order to make the main part visible.
'MAKEFLAGS += -rR' does not become effective for GNU Make < 4.0, but
Debian/Ubuntu is already using newer versions.

The effect of this commit:

  Debian 8 (Jessie)  : Fixed
  Debian 9 (Stretch) : make-kpkg (kernel-package) is not provided
  Ubuntu 14.04 LTS   : NOT Fixed
  Ubuntu 16.04 LTS   : Fixed
  Ubuntu 18.04 LTS   : Fixed

This commit cannot fix Ubuntu 14.04 because it installs GNU Make 3.81,
but its support will end in Apr 2019, which is before the Linux v5.1
release.

I added warning so that nobody would try to include the top Makefile.

Fixes: 3812b8c5c5d5 ("kbuild: make -r/-R effective in top Makefile for old Make versions")
Reported-by: Liz Zhang <lizzha@microsoft.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Lili Deng <v-lide@microsoft.com>
Cc: Manoj Srivastava <srivasta@debian.org>
---

Changes in v2:
  - Drop the unimportant comment about PowerPC

 Makefile | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Makefile b/Makefile
index 4fb8896..6039685 100644
--- a/Makefile
+++ b/Makefile
@@ -31,6 +31,16 @@ _all:
 # descending is started. They are now explicitly listed as the
 # prepare rule.
 
+# Ugly workaround for Debian make-kpkg:
+# make-kpkg directly includes the top Makefile of Linux kernel. In such a case,
+# skip sub-make to support debian_* targets in ruleset/kernel_version.mk, but
+# displays warning to discourage such abusage.
+ifneq ($(word 2, $(MAKEFILE_LIST)),)
+$(warning Do not include top Makefile of Linux Kernel)
+sub-make-done := 1
+MAKEFLAGS += -rR
+endif
+
 ifneq ($(sub-make-done),1)
 
 # Do not use make's built-in rules and variables
-- 
2.7.4

Re: [PATCH v2] kbuild: add workaround for Debian make-kpkg

[Masahiro Yamada]

On Fri, Mar 8, 2019 at 6:15 PM Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
>
> Since commit 3812b8c5c5d5 ("kbuild: make -r/-R effective in top
> Makefile for old Make versions"), make-kpkg is not working.
>
> make-kpkg directly includes the top Makefile of Linux kernel, and
> appends some debian_* targets.
>
>   /usr/share/kernel-package/ruleset/kernel_version.mk:
>
>     # Include the kernel makefile
>     override dot-config := 1
>     include Makefile
>     dot-config := 1
>
> I did not know the kernel Makefile was used in that way, and it is
> hard to guarantee the behavior when the kernel Makefile is included
> by another Makefile from a different project.
>
> It looks like Debian Stretch stopped providing make-kpkg. Maybe it is
> obsolete and being replaced with 'make deb-pkg' etc. but still widely
> used.
>
> This commit adds a workaround; if the top Makefile is included by
> another Makefile, skip sub-make in order to make the main part visible.
> 'MAKEFLAGS += -rR' does not become effective for GNU Make < 4.0, but
> Debian/Ubuntu is already using newer versions.
>
> The effect of this commit:
>
>   Debian 8 (Jessie)  : Fixed
>   Debian 9 (Stretch) : make-kpkg (kernel-package) is not provided
>   Ubuntu 14.04 LTS   : NOT Fixed
>   Ubuntu 16.04 LTS   : Fixed
>   Ubuntu 18.04 LTS   : Fixed
>
> This commit cannot fix Ubuntu 14.04 because it installs GNU Make 3.81,
> but its support will end in Apr 2019, which is before the Linux v5.1
> release.
>
> I added warning so that nobody would try to include the top Makefile.
>
> Fixes: 3812b8c5c5d5 ("kbuild: make -r/-R effective in top Makefile for old Make versions")
> Reported-by: Liz Zhang <lizzha@microsoft.com>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> Tested-by: Lili Deng <v-lide@microsoft.com>
> Cc: Manoj Srivastava <srivasta@debian.org>
> ---

Applied to linux-kbuild.


> Changes in v2:
>   - Drop the unimportant comment about PowerPC
>
>  Makefile | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/Makefile b/Makefile
> index 4fb8896..6039685 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -31,6 +31,16 @@ _all:
>  # descending is started. They are now explicitly listed as the
>  # prepare rule.
>
> +# Ugly workaround for Debian make-kpkg:
> +# make-kpkg directly includes the top Makefile of Linux kernel. In such a case,
> +# skip sub-make to support debian_* targets in ruleset/kernel_version.mk, but
> +# displays warning to discourage such abusage.
> +ifneq ($(word 2, $(MAKEFILE_LIST)),)
> +$(warning Do not include top Makefile of Linux Kernel)
> +sub-make-done := 1
> +MAKEFLAGS += -rR
> +endif
> +
>  ifneq ($(sub-make-done),1)
>
>  # Do not use make's built-in rules and variables
> --
> 2.7.4
>


-- 
Best Regards
Masahiro Yamada

Re: [PATCH v2] kbuild: add workaround for Debian make-kpkg

[Andreas Schwab]

On Mär 08 2019, Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> +$(warning Do not include top Makefile of Linux Kernel)

So how do I add additional targets then?  Currently I create
GNUmakefile, include Makefile, then add the targets I need.  It seems
this is now broken.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: [PATCH v2] kbuild: add workaround for Debian make-kpkg

[Masahiro Yamada]

Hi Andreas,

On Mon, Mar 18, 2019 at 7:00 PM Andreas Schwab <schwab@suse.de> wrote:
>
> On Mär 08 2019, Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>
> > +$(warning Do not include top Makefile of Linux Kernel)
>
> So how do I add additional targets then?  Currently I create
> GNUmakefile, include Makefile, then add the targets I need.  It seems
> this is now broken.


---------(GNUmakefile BEGIN)-----------
your-own-target1:
        echo hello

your-own-target2:
        echo world

# For the rest, fall back to the kernel Makefile
%:
        $(MAKE) -f Makefile $@
---------(GNUmakefile END)-----------



Having said that, my previous cheesy workaround sucks.

How about this patch?
https://patchwork.kernel.org/patch/10858809/

I hope you will be able to wrap the top Makefile again.



-- 
Best Regards
Masahiro Yamada

Re: [PATCH v2] kbuild: add workaround for Debian make-kpkg

[Andreas Schwab]

On Mär 19 2019, Masahiro Yamada <yamada.masahiro@socionext.com> wrote:

> How about this patch?
> https://patchwork.kernel.org/patch/10858809/

Thanks, this makes it work again.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."