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2020-02-27kbuild: get rid of trailing slash from subdir- exampleMasahiro Yamada
obj-* needs a trailing slash for a directory, but subdir-* does not. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-02-27kbuild: remove wrong documentation about mandatory-yMasahiro Yamada
This sentence does not make sense in the section about mandatory-y. This seems to be a copy-paste mistake of commit fcc8487d477a ("uapi: export all headers under uapi directories"). The correct description would be "The convention is to list one mandatory-y per line ...". I just removed it instead of fixing it. If such information is needed, it could be commented in include/asm-generic/Kbuild and include/uapi/asm-generic/Kbuild. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-02-04kbuild: rename hostprogs-y/always to hostprogs/always-yMasahiro Yamada
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 <masahiroy@kernel.org>
2020-02-04kbuild: fix the document to use extra-y for vmlinux.ldsMasahiro Yamada
The difference between "always" and "extra-y" is that the targets listed in $(always) are always built, whereas the ones in $(extra-y) are built only when KBUILD_BUILTIN is set. So, "make modules" does not build the targets in $(extra-y). vmlinux.lds is only needed for linking vmlinux. So, adding it to extra-y is more correct. In fact, arch/x86/kernel/Makefile does this. Fix the example code. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2019-12-22kbuild: clarify the difference between obj-y and obj-m w.r.t. descendingMasahiro Yamada
Kbuild descends into a directory by either 'y' or 'm', but there is an important difference. Kbuild combines the built-in objects into built-in.a in each directory. The built-in.a in the directory visited by obj-y is merged into the built-in.a in the parent directory. This merge happens recursively when Kbuild is ascending back towards the top directory, then built-in objects are linked into vmlinux eventually. This works properly only when the Makefile specifying obj-y is reachable by the chain of obj-y. On the other hand, Kbuild does not take built-in.a from the directory visited by obj-m. This it, all the objects in that directory are supposed to be modular. If Kbuild descends into a directory by obj-m, but the Makefile in the sub-directory specifies obj-y, those objects are just left orphan. The current statement "Kbuild only uses this information to decide that it needs to visit the directory" is misleading. Clarify the difference. Reported-by: Johan Hovold <johan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Johan Hovold <johan@kernel.org>
2019-11-15kbuild: remove header compile testMasahiro Yamada
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 <yamada.masahiro@socionext.com>
2019-10-01kbuild: remove ar-option and KBUILD_ARFLAGSMasahiro Yamada
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 <yamada.masahiro@socionext.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com>
2019-09-04kbuild: remove ARCH_{CPP,A,C}FLAGSMasahiro Yamada
These flags were added by commit 61754c18752f ("kbuild: Allow arch Makefiles to override {cpp,ld,c}flags") to allow ARC to override -O2. We did not see any other usage after all. Now that ARC switched to CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3, there is no more user of these variables. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29kbuild: remove clean-dirs syntaxMasahiro Yamada
The only the difference between clean-files and clean-dirs is the -r option passed to the 'rm' command. You can always pass -r, and then remove the clean-dirs syntax. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29docs: kbuild: remove cc-ldoption from document againMasahiro Yamada
Commit 055efab3120b ("kbuild: drop support for cc-ldoption") correctly removed the cc-ldoption from Documentation/kbuild/makefiles.txt, but commit cd238effefa2 ("docs: kbuild: convert docs to ReST and rename to *.rst") revived it. I guess it was a rebase mistake. Remove it again. Fixes: cd238effefa2 ("docs: kbuild: convert docs to ReST and rename to *.rst") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29docs: kbuild: fix invalid ReST syntaxMasahiro Yamada
I see the following warnings when I open this document with a ReST viewer, retext: /home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1142: (WARNING/2) Inline emphasis start-string without end-string. /home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1152: (WARNING/2) Inline emphasis start-string without end-string. /home/masahiro/ref/linux/Documentation/kbuild/makefiles.rst:1154: (WARNING/2) Inline emphasis start-string without end-string. These hunks were added by commit e846f0dc57f4 ("kbuild: add support for ensuring headers are self-contained") and commit 1e21cbfada87 ("kbuild: support header-test-pattern-y"), respectively. They were written not for ReST but for the plain text, and merged via the kbuild tree. In the same development cycle, this document was converted to ReST by commit cd238effefa2 ("docs: kbuild: convert docs to ReST and rename to *.rst"), and merged via the doc sub-system. Merging them together into Linus' tree resulted in the current situation. To fix the syntax, surround the asterisks with back-quotes, and use :: for the code sample. Fixes: 39ceda5ce1b0 ("Merge tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21kbuild: rebuild modules when module linker scripts are updatedMasahiro Yamada
Currently, the timestamp of module linker scripts are not checked. Add them to the dependency of modules so they are correctly rebuilt. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21kbuild: move KBUILD_LDS, KBUILD_VMLINUX_{OBJS,LIBS} to makefiles.rstMasahiro Yamada
These three variables are not intended to be tweaked by users. Move them from kbuild.rst to makefiles.rst. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21kbuild: do not descend to ./Kbuild when cleaningMasahiro Yamada
'make clean' descends into ./Kbuild, but does not clean anything since everything is added to no-clean-files. There is no need to descend to ./Kbuild in the first place. We can drop the no-clean-files assignment. With this, there is no more user of no-clean-files. I will keep it for a while to see whether a new user will appear. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-20Merge tag 'kbuild-v5.3-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull more Kbuild updates from Masahiro Yamada: - match the directory structure of the linux-libc-dev package to that of Debian-based distributions - fix incorrect include/config/auto.conf generation when Kconfig creates it along with the .config file - remove misleading $(AS) from documents - clean up precious tag files by distclean instead of mrproper - add a new coccinelle patch for devm_platform_ioremap_resource migration - refactor module-related scripts to read modules.order instead of $(MODVERDIR)/*.mod files to get the list of created modules - remove MODVERDIR - update list of header compile-test - add -fcf-protection=none flag to avoid conflict with the retpoline flags when CONFIG_RETPOLINE=y - misc cleanups * tag 'kbuild-v5.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits) kbuild: add -fcf-protection=none when using retpoline flags kbuild: update compile-test header list for v5.3-rc1 kbuild: split out *.mod out of {single,multi}-used-m rules kbuild: remove 'prepare1' target kbuild: remove the first line of *.mod files kbuild: create *.mod with full directory path and remove MODVERDIR kbuild: export_report: read modules.order instead of .tmp_versions/*.mod kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod kbuild: modsign: read modules.order instead of $(MODVERDIR)/*.mod kbuild: modinst: read modules.order instead of $(MODVERDIR)/*.mod scsi: remove pointless $(MODVERDIR)/$(obj)/53c700.ver kbuild: remove duplication from modules.order in sub-directories kbuild: get rid of kernel/ prefix from in-tree modules.{order,builtin} kbuild: do not create empty modules.order in the prepare stage coccinelle: api: add devm_platform_ioremap_resource script kbuild: compile-test headers listed in header-test-m as well kbuild: remove unused hostcc-option kbuild: remove tag files by distclean instead of mrproper kbuild: add --hash-style= and --build-id unconditionally kbuild: get rid of misleading $(AS) from documents ...
2019-07-17kbuild: get rid of misleading $(AS) from documentsMasahiro Yamada
The assembler files in the kernel are *.S instead of *.s, so they must be preprocessed. Since 'as' of GNU binutils is not able to preprocess, we always use $(CC) as an assembler driver. $(AS) is almost unused in Kbuild. As of v5.2, there is just one place that directly invokes $(AS). $ git grep -e '$(AS)' -e '${AS}' -e '$AS' -e '$(AS:' -e '${AS:' -- :^Documentation drivers/net/wan/Makefile: AS68K = $(AS) The documentation about *_AFLAGS* sounds like the flags were passed to $(AS). This is somewhat misleading. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
2019-07-15docs: kbuild: fix build with pdf and fix some minor issuesMauro Carvalho Chehab
The tag ".. include" should be replaced by ".. literalinclude" at issues.rst, otherwise it causes TeX to crash due to excessive usage of stack with Sphinx 2.0. While here, solve a few minor issues at the kbuild book output by adding extra blank lines. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-07-12Merge tag 'kbuild-v5.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - remove headers_{install,check}_all targets - remove unreasonable 'depends on !UML' from CONFIG_SAMPLES - re-implement 'make headers_install' more cleanly - add new header-test-y syntax to compile-test headers - compile-test exported headers to ensure they are compilable in user-space - compile-test headers under include/ to ensure they are self-contained - remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value flags - add -Werror=unknown-warning-option for Clang - add 128-bit built-in types support to genksyms - fix missed rebuild of modules.builtin - propagate 'No space left on device' error in fixdep to Make - allow Clang to use its integrated assembler - improve some coccinelle scripts - add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute path for $(srctree). - do not ignore errors when compression utility is missing - misc cleanups * tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (49 commits) kbuild: use -- separater intead of $(filter-out ...) for cc-cross-prefix kbuild: Inform user to pass ARCH= for make mrproper kbuild: fix compression errors getting ignored kbuild: add a flag to force absolute path for srctree kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree kbuild: remove src and obj from the top Makefile scripts/tags.sh: remove unused environment variables from comments scripts/tags.sh: drop SUBARCH support for ARM kbuild: compile-test kernel headers to ensure they are self-contained kheaders: include only headers into kheaders_data.tar.xz kheaders: remove meaningless -R option of 'ls' kbuild: support header-test-pattern-y kbuild: do not create wrappers for header-test-y kbuild: compile-test exported headers to ensure they are self-contained init/Kconfig: add CONFIG_CC_CAN_LINK kallsyms: exclude kasan local symbols on s390 kbuild: add more hints about SUBDIRS replacement coccinelle: api/stream_open: treat all wait_.*() calls as blocking coccinelle: put_device: Add a cast to an expression for an assignment coccinelle: put_device: Adjust a message construction ...
2019-06-14docs: kbuild: convert docs to ReST and rename to *.rstMauro Carvalho Chehab
The kbuild documentation clearly shows that the documents there are written at different times: some use markdown, some use their own peculiar logic to split sections. Convert everything to ReST without affecting too much the author's style and avoiding adding uneeded markups. The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>