linux/scripts/Makefile.build, branch v5.6

kbuild: rename hostprogs-y/always to hostprogs/always-y

2020-02-03T16:53:07Z

In old days, the "host-progs" syntax was used for specifying host programs. It was renamed to the current "hostprogs-y" in 2004. It is typically useful in scripts/Makefile because it allows Kbuild to selectively compile host programs based on the kernel configuration. This commit renames like follows: always -> always-y hostprogs-y -> hostprogs So, scripts/Makefile will look like this: always-$(CONFIG_BUILD_BIN2C) += ... always-$(CONFIG_KALLSYMS) += ... ... hostprogs := $(always-y) $(always-m) I think this makes more sense because a host program is always a host program, irrespective of the kernel configuration. We want to specify which ones to compile by CONFIG options, so always-y will be handier. The "always", "hostprogs-y", "hostprogs-m" will be kept for backward compatibility for a while. Signed-off-by: Masahiro Yamada

kbuild: use pattern rule for building built-in.a in sub-directories

2020-01-06T17:18:38Z

The built-in.a in a sub-directory is created by descending into that directory. It does not depend on the other sub-directories. Loosen the dependency. Signed-off-by: Masahiro Yamada

kbuild: do not create orphan built-in.a or obj-y objects

2020-01-06T17:18:38Z

Both 'obj-y += foo/' and 'obj-m += foo/' request Kbuild to visit the sub-directory foo/, but the difference is that only the former combines foo/built-in.a into the built-in.a of the current directory because everything in sub-directories visited by obj-m is supposed to be modular. So, it makes sense to create built-in.a only if that sub-directory is reachable by the chain of obj-y. Otherwise, built-in.a will not be linked into vmlinux anyway. For the same reason, it is pointless to compile obj-y objects in the directory visited by obj-m. Signed-off-by: Masahiro Yamada

kbuild: remove header compile test

2019-11-14T15:22:35Z

There are both positive and negative options about this feature. At first, I thought it was a good idea, but actually Linus stated a negative opinion (https://lkml.org/lkml/2019/9/29/227). I admit it is ugly and annoying. The baseline I'd like to keep is the compile-test of uapi headers. (Otherwise, kernel developers have no way to ensure the correctness of the exported headers.) I will maintain a small build rule in usr/include/Makefile. Remove the other header test functionality. Signed-off-by: Masahiro Yamada

kbuild: make single target builds much faster

2019-11-11T11:10:01Z

Since commit 394053f4a4b3 ("kbuild: make single targets work more correctly"), building single targets is really slow. Speed it up by not descending into unrelated directories. Signed-off-by: Masahiro Yamada

kbuild: reduce KBUILD_SINGLE_TARGETS as descending into subdirectories

2019-11-11T11:10:01Z

KBUILD_SINGLE_TARGETS does not need to contain all the targets. Change it to keep track the targets only from the current directory and its subdirectories. Signed-off-by: Masahiro Yamada

kbuild: remove ar-option and KBUILD_ARFLAGS

2019-10-01T00:20:33Z

Commit 40df759e2b9e ("kbuild: Fix build with binutils <= 2.19") introduced ar-option and KBUILD_ARFLAGS to deal with old binutils. According to Documentation/process/changes.rst, the current minimal supported version of binutils is 2.21 so you can assume the 'D' option is always supported. Not only GNU ar but also llvm-ar supports it. With the 'D' option hard-coded, there is no more user of ar-option or KBUILD_ARFLAGS. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers

kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARN

2019-09-06T14:46:52Z

KBUILD_ENABLE_EXTRA_GCC_CHECKS started as a switch to add extra warning options for GCC, but now it is a historical misnomer since we use it also for Clang, DTC, and even kernel-doc. Rename it to more sensible, shorter KBUILD_EXTRA_WARN. For the backward compatibility, KBUILD_ENABLE_EXTRA_GCC_CHECKS is still supported (but not advertised in the documentation). I also fixed up 'make help', and updated the documentation. Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Reviewed-by: Sedat Dilek

kbuild: move modkern_{c,a}flags to Makefile.lib from Makefile.build

2019-08-21T16:14:11Z

Makefile.lib is included by Makefile.modfinal as well as Makefile.build. Move modkern_cflags to Makefile.lib in order to simplify cmd_cc_o_c in Makefile.modfinal. Move modkern_cflags as well for consistency. Signed-off-by: Masahiro Yamada

kbuild: add CONFIG_ASM_MODVERSIONS

2019-08-21T16:14:11Z

Add CONFIG_ASM_MODVERSIONS. This allows to remove one if-conditional nesting in scripts/Makefile.build. scripts/Makefile.build is run every time Kbuild descends into a sub-directory. So, I want to avoid $(wildcard ...) evaluation where possible although computing $(wildcard ...) is so cheap that it may not make measurable performance difference. Signed-off-by: Masahiro Yamada Acked-by: Geert Uytterhoeven