| Message ID | 20240917141725.466514-22-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | kbuild: support building external modules in a separate build directory | expand |
On Tue, Sep 17, 2024 at 11:16:49PM +0900, Masahiro Yamada wrote: > Keep the consistent behavior when this Makefile is invoked from another > directory. > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- > > Makefile | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Hi Masahiro, On 9/17/24 16:16, Masahiro Yamada wrote: > Keep the consistent behavior when this Makefile is invoked from another > directory. This breaks building in a chroot for me. I usually compile the kernel on my host and then use some tooling to just run the "package" step of an Alpine kernel package definition. See https://wiki.postmarketos.org/wiki/Compiling_kernels_with_envkernel.sh#Packaging_kernels_built_without_envkernel Since this requires mounting the source directory into a chroot, and then symlinking the output directory to the package "src" dir. It relies on the fact that make can be run from the output directory and implicitly relies on the include being relative since the absolute paths don't map inside the chroot. I'm not sure if breakages like this justify a revert, but I noticed this issue in -next the other day and thought it was at least worth reporting. I wouldn't be surprised if other folks with other build systems get bitten by this too. Kind regards, Caleb > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- > > Makefile | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/Makefile b/Makefile > index ce646a6994a6..9f0ba07e8f25 100644 > --- a/Makefile > +++ b/Makefile > @@ -643,8 +643,9 @@ ifdef building_out_of_srctree > > quiet_cmd_makefile = GEN Makefile > cmd_makefile = { \ > - echo "\# Automatically generated by $(srctree)/Makefile: don't edit"; \ > - echo "include $(srctree)/Makefile"; \ > + echo "\# Automatically generated by $(abs_srctree)/Makefile: don't edit"; \ > + echo "export KBUILD_OUTPUT = $(CURDIR)"; \ > + echo "include $(abs_srctree)/Makefile"; \ > } > Makefile > > outputmakefile:
On Sat, Nov 30, 2024 at 8:31 AM Caleb Connolly <caleb.connolly@linaro.org> wrote: > > Hi Masahiro, > > On 9/17/24 16:16, Masahiro Yamada wrote: > > Keep the consistent behavior when this Makefile is invoked from another > > directory. > > This breaks building in a chroot for me. I usually compile the kernel on > my host and then use some tooling to just run the "package" step of an > Alpine kernel package definition. See > > https://wiki.postmarketos.org/wiki/Compiling_kernels_with_envkernel.sh#Packaging_kernels_built_without_envkernel > > Since this requires mounting the source directory into a chroot, and > then symlinking the output directory to the package "src" dir. It relies > on the fact that make can be run from the output directory and > implicitly relies on the include being relative since the absolute paths > don't map inside the chroot. I do not understand what is happening in your workflow, but presumably you need to come up with a solution on your end (or in the pmos community). - Kbuild never promised that $(srctree) is always a relative path. $(srctree) is relative only when building in-tree (srctree=.) or when the output directory is a sub-directory of the source tree. (srctree=..) For other cases, $(srctree) is an absolute path. Therefore, "include directive with an absolute path" is not something new. - The wrapper Makefile generated in the output directory is a bonus convenience for humans. It is not even required to build the kernel from scripts. Your report seems like a jungle of a chroot and mounts with a symlink. I guess it just happened to work, relying on something Kbuild did not support. > > I'm not sure if breakages like this justify a revert, but I noticed this > issue in -next the other day and thought it was at least worth reporting. Thanks for the report, but I do not think this is worth a revert for the above reasons. > I wouldn't be surprised if other folks with other build systems get > bitten by this too. > > Kind regards, > Caleb > > > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > --- > > > > Makefile | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/Makefile b/Makefile > > index ce646a6994a6..9f0ba07e8f25 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -643,8 +643,9 @@ ifdef building_out_of_srctree > > > > quiet_cmd_makefile = GEN Makefile > > cmd_makefile = { \ > > - echo "\# Automatically generated by $(srctree)/Makefile: don't edit"; \ > > - echo "include $(srctree)/Makefile"; \ > > + echo "\# Automatically generated by $(abs_srctree)/Makefile: don't edit"; \ > > + echo "export KBUILD_OUTPUT = $(CURDIR)"; \ > > + echo "include $(abs_srctree)/Makefile"; \ > > } > Makefile > > > > outputmakefile: >
diff --git a/Makefile b/Makefile index ce646a6994a6..9f0ba07e8f25 100644 --- a/Makefile +++ b/Makefile @@ -643,8 +643,9 @@ ifdef building_out_of_srctree quiet_cmd_makefile = GEN Makefile cmd_makefile = { \ - echo "\# Automatically generated by $(srctree)/Makefile: don't edit"; \ - echo "include $(srctree)/Makefile"; \ + echo "\# Automatically generated by $(abs_srctree)/Makefile: don't edit"; \ + echo "export KBUILD_OUTPUT = $(CURDIR)"; \ + echo "include $(abs_srctree)/Makefile"; \ } > Makefile outputmakefile:
Keep the consistent behavior when this Makefile is invoked from another directory. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- Makefile | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)