kernel/linux.git/scripts/Makefile.clean, branch v6.6.132

kbuild: make clean rule robust against too long argument error

2023-06-25T14:12:20+00:00

Commit cd968b97c492 ("kbuild: make built-in.a rule robust against too long argument error") made a build rule robust against "Argument list too long" error. Eugeniu Rosca reported the same error occurred when cleaning an external module. The $(obj)/ prefix can be a very long path for external modules. Apply a similar solution to 'make clean'. Reported-by: Eugeniu Rosca Signed-off-by: Masahiro Yamada Reviewed-by: Eugeniu Rosca Tested-by: Eugeniu Rosca

kbuild: add kbuild-file macro

2022-11-22T14:40:02+00:00

While building, installing, cleaning, Kbuild visits sub-directories and includes 'Kbuild' or 'Makefile' that exists there. Add 'kbuild-file' macro, and reuse it from scripts/Makefie.* Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Reviewed-by: Alexander Lobakin Tested-by: Alexander Lobakin

kbuild: drop $(objtree)/ prefix support for clean-files

2022-05-07T18:17:00+00:00

I think this hack is a bad idea. arch/powerpc/boot/Makefile is the only and last user. Let's stop doing this. Signed-off-by: Masahiro Yamada Acked-by: Michael Ellerman (powerpc)

kbuild: replace $(if A,A,B) with $(or A,B)

2022-02-15T03:25:56+00:00

$(or ...) is available since GNU Make 3.81, and useful to shorten the code in some places. Covert as follows: $(if A,A,B) --> $(or A,B) This patch also converts: $(if A, A, B) --> $(or A, B) Strictly speaking, the latter is not an equivalent conversion because GNU Make keeps spaces after commas; if A is not empty, $(if A, A, B) expands to " A", while $(or A, B) expands to "A". Anyway, preceding spaces are not significant in the code hunks I touched. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier

kbuild: prefix $(srctree)/ to some included Makefiles

2021-03-15T10:20:48+00:00

VPATH is used in Kbuild to make pattern rules search for prerequisites in both $(objtree) and $(srctree). Some of *.c, *.S files are not real sources, but generated by tools such as flex, bison, perl. In contrast, I doubt the benefit of --include-dir=$(abs_srctree) because it is always clear which Makefiles are real sources, and which are not. So, my hope is to add $(srctree)/ prefix to all check-in Makefiles, then remove --include-dir=$(abs_srctree) flag in the future. I am touching only some Kbuild core parts for now. Treewide fixes will be needed to achieve this goal. Signed-off-by: Masahiro Yamada

kbuild: remove deprecated 'always' and 'hostprogs-y/m'

2021-02-24T06:12:06+00:00

These have no more user in the upstream code. The use of them has been warned for a while for external modules. The migration is finished. Signed-off-by: Masahiro Yamada

kbuild: introduce hostprogs-always-y and userprogs-always-y

2020-08-09T16:32:59+00:00

To build host programs, you need to add the program names to 'hostprogs' to use the necessary build rule, but it is not enough to build them because there is no dependency. There are two types of host programs: built as the prerequisite of another (e.g. gen_crc32table in lib/Makefile), or always built when Kbuild visits the Makefile (e.g. genksyms in scripts/genksyms/Makefile). The latter is typical in Makefiles under scripts/, which contains host programs globally used during the kernel build. To build them, you need to add them to both 'hostprogs' and 'always-y'. This commit adds hostprogs-always-y as a shorthand. The same applies to user programs. net/bpfilter/Makefile builds bpfilter_umh on demand, hence always-y is unneeded. In contrast, programs under samples/ are added to both 'userprogs' and 'always-y' so they are always built when Kbuild visits the Makefiles. userprogs-always-y works as a shorthand. Signed-off-by: Masahiro Yamada Acked-by: Miguel Ojeda

kbuild: move host .so build rules to scripts/gcc-plugins/Makefile

2020-08-09T16:32:59+00:00

The host shared library rules are currently implemented in scripts/Makefile.host, but actually GCC-plugin is the only user of them. (The VDSO .so files are built for the target by different build rules) Hence, they do not need to be treewide available. Move all the relevant build rules to scripts/gcc-plugins/Makefile. I also optimized the build steps so *.so is directly built from .c because every upstream plugin is compiled from a single source file. I am still keeping the multi-file plugin support, which Kees Cook mentioned might be needed by out-of-tree plugins. (https://lkml.org/lkml/2019/1/11/1107) If the plugin, foo.so, is compiled from two files foo.c and foo2.c, then you can do like follows: foo-objs := foo.o foo2.o Single-file plugins do not need the *-objs notation. Signed-off-by: Masahiro Yamada Acked-by: Kees Cook

kbuild: add infrastructure to build userspace programs

2020-05-17T09:52:01+00:00

Kbuild supports the infrastructure to build host programs, but there was no support to build userspace programs for the target architecture (i.e. the same architecture as the kernel). Sam Ravnborg worked on this in 2014 (https://lkml.org/lkml/2014/7/13/154), but it was not merged. One problem at that time was, there was no good way to know whether $(CC) can link standalone programs. In fact, pre-built kernel.org toolchains [1] are often used for building the kernel, but they do not provide libc. Now, we can handle this cleanly because the compiler capability is evaluated at the Kconfig time. If $(CC) cannot link standalone programs, the relevant options are hidden by 'depends on CC_CAN_LINK'. The implementation just mimics scripts/Makefile.host The userspace programs are compiled with the same flags as the host programs. In addition, it uses -m32 or -m64 if it is found in $(KBUILD_CFLAGS). This new syntax has two usecases. - Sample programs Several userspace programs under samples/ include UAPI headers installed in usr/include. Most of them were previously built for the host architecture just to use the 'hostprogs' syntax. However, 'make headers' always works for the target architecture. This caused the arch mismatch in cross-compiling. To fix this distortion, sample code should be built for the target architecture. - Bpfilter net/bpfilter/Makefile compiles bpfilter_umh as the user mode helper, and embeds it into the kernel. Currently, it overrides HOSTCC with CC to use the 'hostprogs' syntax. This hack should go away. [1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/ Signed-off-by: Masahiro Yamada Acked-by: Sam Ravnborg

gcc-plugins: drop support for GCC <= 4.7

2020-04-08T15:13:45+00:00

Nobody was opposed to raising minimum GCC version to 4.8 [1] So, we will drop GCC <= 4.7 support sooner or later. We always use C++ compiler for building plugins for GCC >= 4.8. This commit drops the plugin support for GCC <= 4.7 a bit earlier, which allows us to dump lots of code. [1] https://lkml.org/lkml/2020/1/23/545 Signed-off-by: Masahiro Yamada Acked-by: Kees Cook