Messages in this thread | | | From | Florian Fainelli <> | Subject | Proper use for linking foo.o_shipped after 69ea912fda74 ("kbuild: remove unneeded link_multi_deps")? | Date | Tue, 5 May 2020 21:45:08 -0700 |
| |
Hi Masahiro, Michal,
While updating our systems from 4.9 to 5.4, we noticed that one of the kernel modules that we build, which is done by linking an object that we pre-compile out of Kbuild stopped working.
I bisected it down to:
commit 69ea912fda74a673d330d23595385e5b73e3a2b9 (refs/bisect/bad) Author: Masahiro Yamada <yamada.masahiro@socionext.com> Date: Thu Oct 4 13:25:19 2018 +0900
kbuild: remove unneeded link_multi_deps
Since commit c8589d1e9e01 ("kbuild: handle multi-objs dependency appropriately"), $^ really represents all the prerequisite of the composite object being built.
Hence, $(filter %.o,$^) contains all the objects to link together, which is much simpler than link_multi_deps calculation.
Please note $(filter-out FORCE,$^) does not work here. When a single object module is turned into a multi object module, $^ will contain header files that were previously included for building the single object, and recorded in the .*.cmd file. To filter out such headers, $(filter %.o,$^) should be used here.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
and the linker now fails with the following:
mkdir -p /home/florian/dev/lkm/.tmp_versions ; rm -f /home/florian/dev/lkm/.tmp_versions/*
WARNING: Symbol version dump ./Module.symvers is missing; modules will have no dependencies and modversions.
make -f ./scripts/Makefile.build obj=/home/florian/dev/lkm (cat /dev/null; echo kernel//home/florian/dev/lkm/hello.ko;) > /home/florian/dev/lkm/modules.order ld -m elf_x86_64 -z max-page-size=0x200000 -r -o /home/florian/dev/lkm/hello.o ld: no input files make[1]: *** [scripts/Makefile.build:492: /home/florian/dev/lkm/hello.o] Error 1 make: *** [Makefile:1530: _module_/home/florian/dev/lkm] Error 2
and here are some steps to reproduce this:
Kbuild: obj-m := hello.o hello-y := test.o_shipped
test.c can be a simple hello world, and you can compile it using a standard Kbuild file first, and then move test.o as test.o_shipped.
I am afraid I do not speak Kbuild fluently enough to recommend a fix for that.
Thanks! -- Florian
| |