Re: [PATCH] kbuild: use $(abspath ...) instead of $(shell cd ... && /bin/pwd)

From: Thierry Reding
Date: Mon Aug 21 2017 - 04:54:05 EST


On Sun, Aug 20, 2017 at 03:04:11PM +0900, Masahiro Yamada wrote:
> Kbuild conventionally uses $(shell cd ... && /bin/pwd) idiom to get
> the absolute path of the directory because GNU Make 3.80, the minimal
> supported version at that time, did not support $(abspath ...) or
> $(realpath ...).
>
> Commit 37d69ee30808 ("docs: bump minimal GNU Make version to 3.81")
> dropped the GNU Make 3.80 support, so we are now allowed to use those
> make-builtin helpers.
>
> This conversion will provide better portability without relying on
> the pwd command or its location /bin/pwd.
>
> I am intentionally using $(realpath ...) instead $(abspath ...) in
> some places. The difference between the two is $(realpath ...)
> returns an empty string if the given path does not exist. It is
> convenient in places where we need to error-out if the makefile fails
> to create an output directory.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> ---
>
> Makefile | 12 ++++++------
> scripts/gdb/linux/Makefile | 2 +-
> tools/power/cpupower/Makefile | 2 +-
> tools/scripts/Makefile.include | 6 +++---
> 4 files changed, 11 insertions(+), 11 deletions(-)

This looks very similar to a patch I had written a long time ago:

Acked-by: Thierry Reding <treding@xxxxxxxxxx>

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