linux/scripts/package/mkspec

154 lines
5 KiB

kbuild: create *.mod with full directory path and remove MODVERDIR While descending directories, Kbuild produces objects for modules, but do not link final *.ko files; it is done in the modpost. To keep track of modules, Kbuild creates a *.mod file in $(MODVERDIR) for every module it is building. Some post-processing steps read the necessary information from *.mod files. This avoids descending into directories again. This mechanism was introduced in 2003 or so. Later, commit 551559e13af1 ("kbuild: implement modules.order") added modules.order. So, we can simply read it out to know all the modules with directory paths. This is easier than parsing the first line of *.mod files. $(MODVERDIR) has a flat directory structure, that is, *.mod files are named only with base names. This is based on the assumption that the module name is unique across the tree. This assumption is really fragile. Stephen Rothwell reported a race condition caused by a module name conflict: https://lkml.org/lkml/2019/5/13/991 In parallel building, two different threads could write to the same $(MODVERDIR)/*.mod simultaneously. Non-unique module names are the source of all kind of troubles, hence commit 3a48a91901c5 ("kbuild: check uniqueness of module names") introduced a new checker script. However, it is still fragile in the build system point of view because this race happens before scripts/modules-check.sh is invoked. If it happens again, the modpost will emit unclear error messages. To fix this issue completely, create *.mod with full directory path so that two threads never attempt to write to the same file. $(MODVERDIR) is no longer needed. Since modules with directory paths are listed in modules.order, Kbuild is still able to find *.mod files without additional descending. I also killed cmd_secanalysis; scripts/mod/sumversion.c computes MD4 hash for modules with MODULE_VERSION(). When CONFIG_DEBUG_SECTION_MISMATCH=y, it occurs not only in the modpost stage, but also during directory descending, where sumversion.c may parse stale *.mod files. It would emit 'No such file or directory' warning when an object consisting a module is renamed, or when a single-obj module is turned into a multi-obj module or vice versa. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Nicolas Pitre <nico@fluxnic.net>
2019-07-17 15:17:57 +09:00
kbuild: do not create wrappers for header-test-y header-test-y does not work with headers in sub-directories. For example, you may want to write a Makefile, like this: include/linux/Kbuild: header-test-y += mtd/nand.h This entry will create a wrapper include/linux/mtd/nand.hdrtest.c with the following content: #include "mtd/nand.h" To make this work, we need to add $(srctree)/include/linux to the header search path. It would be tedious to add ccflags-y. Instead, we could change the *.hdrtest.c rule to wrap: #include "nand.h" This works for in-tree build since #include "..." searches in the relative path from the header with this directive. For O=... build, we need to add $(srctree)/include/linux/mtd to the header search path, which will be even more tedious. After all, I thought it would be handier to compile headers directly without creating wrappers. I added a new build rule to compile %.h into %.h.s The target is %.h.s instead of %.h.o because it is slightly faster. Also, as for GCC, an empty assembly is smaller than an empty object. I wrote the build rule: $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $< instead of: $(CC) $(c_flags) -S -o $@ -x c $< Both work fine with GCC, but the latter is bad for Clang. This comes down to the difference in the -Wunused-function policy. GCC does not warn about unused 'static inline' functions at all. Clang does not warn about the ones in included headers, but does about the ones in the source. So, we should handle headers as headers, not as source files. In fact, this has been hidden since commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused static inline functions"), but we should not rely on that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Tested-by: Jani Nikula <jani.nikula@intel.com>
2019-07-01 09:58:41 +09:00
kbuild: rpm-pkg: fix build error when _arch is undefined Cross-building (bin)rpm-pkg fails on several architectures. For example, 'make ARCH=arm binrpm-pkg' fails like follows: sh ./scripts/package/mkspec prebuilt > ./binkernel.spec rpmbuild --define "_builddir ." --target \ arm -bb ./binkernel.spec Building target platforms: arm Building for target arm warning: line 19: It's not recommended to have unversioned Obsoletes: Obsoletes: kernel-headers Executing(%install): /bin/sh -e /var/tmp/rpm-tmp.0S8t2F + umask 022 + cd . + mkdir -p /home/masahiro/rpmbuild/BUILDROOT/kernel-5.19.0_rc6-19.%{_arch}/boot + make -f ./Makefile image_name + cp arch/arm/boot/zImage /home/masahiro/rpmbuild/BUILDROOT/kernel-5.19.0_rc6-19.%{_arch}/boot/vmlinuz-5.19.0-rc6 + make -f ./Makefile INSTALL_MOD_PATH=/home/masahiro/rpmbuild/BUILDROOT/kernel-5.19.0_rc6-19.%{_arch} modules_install make[3]: *** No rule to make target '/home/masahiro/rpmbuild/BUILDROOT/kernel-5.19.0_rc6-19.arch/arm/crypto/aes-arm-bs.ko{_arch}/lib/modules/5.19.0-rc6/kernel/%', needed by '__modinst'. Stop. make[2]: *** [Makefile:1768: modules_install] Error 2 error: Bad exit status from /var/tmp/rpm-tmp.0S8t2F (%install) By default, 'buildroot' contains %{_arch} (see /usr/lib/rpm/macros). _arch is generally defined in /usr/lib/rpm/platforms/*/macros, where the platform sub-directory is specified by --target= option for cross builds. If the given arch does not exist, %{_arch} is not expanded. In the example above, --target=arm is passed to rpmbuild, but /usr/lib/rpm/platforms/arm-linux/ does not exist. The '%' character in the path confuses GNU make and rpmbuild. The same occurs for such architectures as csky, microblaze, nios2, etc. Define _arch if it has not been defined. Reported-by: Jason Self <jason@bluehome.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-07-14 14:02:40 +09:00