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2020-06-13Merge tag 'kbuild-v5.8-2' of ↵Linus Torvalds1-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull more Kbuild updates from Masahiro Yamada: - fix build rules in binderfs sample - fix build errors when Kbuild recurses to the top Makefile - covert '---help---' in Kconfig to 'help' * tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: treewide: replace '---help---' in Kconfig files with 'help' kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables samples: binderfs: really compile this sample and fix build issues
2020-06-11Rebase locking/kcsan to locking/urgentThomas Gleixner1-0/+10
Merge the state of the locking kcsan branch before the read/write_once() and the atomics modifications got merged. Squash the fallout of the rebase on top of the read/write once and atomic fallback work into the merge. The history of the original branch is preserved in tag locking-kcsan-2020-06-02. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-11kbuild: fix broken builds because of GZIP,BZIP2,LZOP variablesDenis Efremov1-3/+3
Redefine GZIP, BZIP2, LZOP variables as KGZIP, KBZIP2, KLZOP resp. GZIP, BZIP2, LZOP env variables are reserved by the tools. The original attempt to redefine them internally doesn't work in makefiles/scripts intercall scenarios, e.g., "make GZIP=gzip bindeb-pkg" and results in broken builds. There can be other broken build commands because of this, so the universal solution is to use non-reserved env variables for the compression tools. Fixes: 8dfb61dcbace ("kbuild: add variables for compression tools") Signed-off-by: Denis Efremov <efremov@linux.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-06kbuild: add variables for compression toolsDenis Efremov1-6/+6
Allow user to use alternative implementations of compression tools, such as pigz, pbzip2, pxz. For example, multi-threaded tools to speed up the build: $ make GZIP=pigz BZIP2=pbzip2 Variables _GZIP, _BZIP2, _LZOP are used internally because original env vars are reserved by the tools. The use of GZIP in gzip tool is obsolete since 2015. However, alternative implementations (e.g., pigz) still rely on it. BZIP2, BZIP, LZOP vars are not obsolescent. The credit goes to @grsecurity. As a sidenote, for multi-threaded lzma, xz compression one can use: $ export XZ_OPT="--threads=0" Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-03kbuild: update modules.order only when contained modules are updatedMasahiro Yamada1-13/+14
Make modules.order depend on $(obj-m), and use if_changed to build it. This will avoid unneeded update of modules.order, which will be useful to optimize the modpost stage. Currently, the second pass of modpost is always invoked. By checking the timestamp of modules.order, we can avoid the unneeded modpost. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-01kbuild: refactor subdir-ym calculationMasahiro Yamada1-9/+4
Remove the unneeded variables, __subdir-y and __subdir-m. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-05-25kbuild: make modules.order rule consistent with built-in.aMasahiro Yamada1-0/+2
built-in.a contains the built-in object paths from the current and sub directories. module.order collects the module paths from the current and sub directories. Make their build rules look more symmetrical. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-05-25kbuild: move subdir-obj-y to scripts/Makefile.buildMasahiro Yamada1-5/+0
Save $(addprefix ...) for subdir-obj-y. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-05-17kbuild: warn if always, hostprogs-y, or hostprogs-m is usedMasahiro Yamada1-1/+11
always, hostprogs-y, and hostprogs-m are deprecated. There is no user in upstream code, but I will keep them for external modules. I want to remove them entirely someday. Prompt downstream users for the migration. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-05-12kbuild: determine the output format of DTC by the target suffixMasahiro Yamada1-3/+3
cmd_dtc takes the additional parameter $(2) to select the target format, dtb or yaml. This makes things complicated when it is used with cmd_and_fixdep and if_changed_rule. I actually stumbled on this. See commit 3d4b2238684a ("kbuild: fix DT binding schema rule again to avoid needless rebuilds"). Extract the suffix part of the target instead of passing the parameter. Fortunately, this works for both $(obj)/%.dtb and $(obj)/%.dt.yaml . Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-05-12kbuild: use -MMD instead of -MD to exclude system headers from dependencyMasahiro Yamada1-4/+4
This omits system headers from the generated header dependency. System headers are not updated unless you upgrade the compiler. Nor do they contain CONFIG options, so fixdep does not need to parse them. Having said that, the effect of this optimization will be quite small because the kernel code generally does not include system headers except <stdarg.h>. Host programs include a lot of system headers, but there are not so many in the kernel tree. At first, keeping system headers in .*.cmd files might be useful to detect the compiler update, but there is no guarantee that <stdarg.h> is included from every file. So, I implemented a more reliable way in the previous commit. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-23kbuild: fix DT binding schema rule again to avoid needless rebuildsMasahiro Yamada1-1/+1
Since commit 7a0496056064 ("kbuild: fix DT binding schema rule to detect command line changes"), this rule is every time re-run even if you change nothing. cmd_dtc takes one additional parameter to pass to the -O option of dtc. We need to pass 'yaml' to if_changed_rule. Otherwise, cmd-check invoked from if_changed_rule is false positive. Fixes: 7a0496056064 ("kbuild: fix DT binding schema rule to detect command line changes") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-04-13Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refreshIngo Molnar1-1/+2
Resolve these conflicts: arch/x86/Kconfig arch/x86/kernel/Makefile Do a minor "evil merge" to move the KCSAN entry up a bit by a few lines in the Kconfig to reduce the probability of future conflicts. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-03-21Merge branch 'linus' into locking/kcsan, to pick up fixesIngo Molnar1-3/+3
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-03-21Merge branch 'x86/kdump' into locking/kcsan, to resolve conflictsIngo Molnar1-8/+19
Conflicts: arch/x86/purgatory/Makefile Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-03-03kbuild: Always validate DT binding examplesRob Herring1-1/+2
Most folks only run dt_binding_check on the single schema they care about by setting DT_SCHEMA_FILES. That means example is only checked against that one schema which is not always sufficient. Let's address this by splitting processed-schema.yaml into 2 files: one that's always all schemas for the examples and one that's just the schema in DT_SCHEMA_FILES for dtbs. Co-developed-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-02-26kbuild: remove unneeded semicolon at the end of cmd_dtb_checkMasahiro Yamada1-1/+1
This trailing semicolon is unneeded. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Rob Herring <robh@kernel.org>
2020-02-26kbuild: fix DT binding schema rule to detect command line changesMasahiro Yamada1-2/+2
This if_change_rule is not working properly; it cannot detect any command line change. The reason is because cmd-check in scripts/Kbuild.include compares $(cmd_$@) and $(cmd_$1), but cmd_dtc_dt_yaml does not exist here. For if_change_rule to work properly, the stem part of cmd_* and rule_* must match. Because this cmd_and_fixdep invokes cmd_dtc, this rule must be named rule_dtc. Fixes: 4f0e3a57d6eb ("kbuild: Add support for DT binding schema checks") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Rob Herring <robh@kernel.org>
2020-02-03kbuild: rename hostprogs-y/always to hostprogs/always-yMasahiro Yamada1-1/+5
In old days, the "host-progs" syntax was used for specifying host programs. It was renamed to the current "hostprogs-y" in 2004. It is typically useful in scripts/Makefile because it allows Kbuild to selectively compile host programs based on the kernel configuration. This commit renames like follows: always -> always-y hostprogs-y -> hostprogs So, scripts/Makefile will look like this: always-$(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>
2020-01-06kbuild: pass KBUILD_MODFILE when compiling builtin objectsMasahiro Yamada1-6/+9
When compiling, Kbuild passes KBUILD_BASENAME (basename of the object) and KBUILD_MODNAME (basename of the module). This commit adds another one, KBUILD_MODFILE, which is the path of the module. (or, the path of the module it would end up in if it were compiled as a module.) The next commit will use this to generate modules.builtin without tristate.conf. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-01-06kbuild: add stringify helper to quote a string passed to C filesMasahiro Yamada1-1/+1
Make $(squote)$(quote)...$(quote)$(squote) a helper macro. I will reuse it in the next commit. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-01-06kbuild: do not create orphan built-in.a or obj-y objectsMasahiro Yamada1-0/+4
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 <masahiroy@kernel.org>
2019-12-30Merge tag 'v5.5-rc4' into locking/kcsan, to resolve conflictsIngo Molnar1-14/+0
Conflicts: init/main.c lib/Kconfig.debug Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-16kcsan: Add Kernel Concurrency Sanitizer infrastructureMarco Elver1-0/+10
Kernel Concurrency Sanitizer (KCSAN) is a dynamic data-race detector for kernel space. KCSAN is a sampling watchpoint-based data-race detector. See the included Documentation/dev-tools/kcsan.rst for more details. This patch adds basic infrastructure, but does not yet enable KCSAN for any architecture. Signed-off-by: Marco Elver <elver@google.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-11-14kbuild: remove header compile testMasahiro Yamada1-14/+0
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 Yamada1-1/+1
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>
2019-09-06kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARNMasahiro Yamada1-2/+2
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 <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
2019-09-04kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)Masahiro Yamada1-5/+8
Kbuild provides per-file compiler flag addition/removal: CFLAGS_<basetarget>.o CFLAGS_REMOVE_<basetarget>.o AFLAGS_<basetarget>.o AFLAGS_REMOVE_<basetarget>.o CPPFLAGS_<basetarget>.lds HOSTCFLAGS_<basetarget>.o HOSTCXXFLAGS_<basetarget>.o The <basetarget> is the filename of the target with its directory and suffix stripped. This syntax comes into a trouble when two files with the same basename appear in one Makefile, for example: obj-y += foo.o obj-y += dir/foo.o CFLAGS_foo.o := <some-flags> Here, the <some-flags> applies to both foo.o and dir/foo.o The real world problem is: scripts/kconfig/util.c scripts/kconfig/lxdialog/util.c Both files are compiled into scripts/kconfig/mconf, but only the latter should be given with the ncurses flags. It is more sensible to use the relative path to the Makefile, like this: obj-y += foo.o CFLAGS_foo.o := <some-flags> obj-y += dir/foo.o CFLAGS_dir/foo.o := <other-flags> At first, I attempted to replace $(basetarget) with $*. The $* variable is replaced with the stem ('%') part in a pattern rule. This works with most of cases, but does not for explicit rules. For example, arch/ia64/lib/Makefile reuses rule_as_o_S in its own explicit rules, so $* will be empty, resulting in ignoring the per-file AFLAGS. I introduced a new variable, target-stem, which can be used also from explicit rules. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Marc Zyngier <maz@kernel.org>
2019-09-04kbuild: add $(BASH) to run scripts with bash-extensionMasahiro Yamada1-1/+1
CONFIG_SHELL falls back to sh when bash is not installed on the system, but nobody is testing such a case since bash is usually installed. So, shell scripts invoked by CONFIG_SHELL are only tested with bash. It makes it difficult to test whether the hashbang #!/bin/sh is real. For example, #!/bin/sh in arch/powerpc/kernel/prom_init_check.sh is false. (I fixed it up) Besides, some shell scripts invoked by CONFIG_SHELL use bash-extension and #!/bin/bash is specified as the hashbang, while CONFIG_SHELL may not always be set to bash. Probably, the right thing to do is to introduce BASH, which is bash by default, and always set CONFIG_SHELL to sh. Replace $(CONFIG_SHELL) with $(BASH) for bash scripts. If somebody tries to add bash-extension to a #!/bin/sh script, it will be caught in testing because /bin/sh is a symlink to dash on some major distributions. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21kbuild: move modkern_{c,a}flags to Makefile.lib from Makefile.buildMasahiro Yamada1-0/+12
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 <yamada.masahiro@socionext.com>
2019-08-14kbuild: treat an object as multi-used when $(foo-) is setMasahiro Yamada1-5/+5
Currently, Kbuild treats an object as multi-used when any of $(foo-objs), $(foo-y), $(foo-m) is set. It makes more sense to check $(foo-) as well. In the context of foo-$(CONFIG_FOO_FEATURE1), CONFIG_FOO_FEATURE1 could be unset. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-13kbuild: move flex and bison rules to Makefile.hostMasahiro Yamada1-16/+0
Flex and bison are used for kconfig, dtc, genksyms, all of which are host programs. I never imagine the kernel embeds a parser or a lexer. Move the flex and bison rules to scripts/Makefile.host. This file is included only when hostprogs-y etc. is present in the Makefile in the directory. So, parsing these rules are skipped in most of directories. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-13kbuild: make bison create C file and header in a single pattern ruleMasahiro Yamada1-9/+3
We generally expect bison to create not only a C file, but also a header, which will be included from the lexer. Currently, Kbuild generates them in separate rules. So, for instance, when building Kconfig, you will notice bison is invoked twice: HOSTCC scripts/kconfig/conf.o HOSTCC scripts/kconfig/confdata.o HOSTCC scripts/kconfig/expr.o LEX scripts/kconfig/lexer.lex.c YACC scripts/kconfig/parser.tab.h HOSTCC scripts/kconfig/lexer.lex.o YACC scripts/kconfig/parser.tab.c HOSTCC scripts/kconfig/parser.tab.o HOSTCC scripts/kconfig/preprocess.o HOSTCC scripts/kconfig/symbol.o HOSTLD scripts/kconfig/conf Make handles such cases nicely in pattern rules [1]. Merge the two rules so that one invokcation of bison can generate both of them. HOSTCC scripts/kconfig/conf.o HOSTCC scripts/kconfig/confdata.o HOSTCC scripts/kconfig/expr.o LEX scripts/kconfig/lexer.lex.c YACC scripts/kconfig/parser.tab.[ch] HOSTCC scripts/kconfig/lexer.lex.o HOSTCC scripts/kconfig/parser.tab.o HOSTCC scripts/kconfig/preprocess.o HOSTCC scripts/kconfig/symbol.o HOSTLD scripts/kconfig/conf [1] Pattern rule GNU Make manual says: "Pattern rules may have more than one target. Unlike normal rules, this does not act as many different rules with the same prerequisites and recipe. If a pattern rule has multiple targets, make knows that the rule's recipe is responsible for making all of the targets. The recipe is executed only once to make all the targets. When searching for a pattern rule to match a target, the target patterns of a rule other than the one that matches the target in need of a rule are incidental: make worries only about giving a recipe and prerequisites to the file presently in question. However, when this file's recipe is run, the other targets are marked as having been updated themselves." https://www.gnu.org/software/make/manual/html_node/Pattern-Intro.html Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-27kbuild: remove unused single-used-mMasahiro Yamada1-2/+0
This is unused since commit 9f69a496f100 ("kbuild: split out *.mod out of {single,multi}-used-m rules"). Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-17kbuild: compile-test headers listed in header-test-m as wellMasahiro Yamada1-1/+1
It will be useful to control the header-test by a tristate option. If CONFIG_FOO is a tristate option, you can write like this: header-test-$(CONFIG_FOO) += foo.h Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-10kbuild: fix compression errors getting ignoredHarald Seiler1-5/+5
A missing compression utility or other errors were not picked up by make and an empty kernel image was produced. By removing the &&, errors will no longer be ignored. Signed-off-by: Harald Seiler <hws@denx.de> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-10kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctreeMasahiro Yamada1-1/+1
Commit 25b146c5b8ce ("kbuild: allow Kbuild to start from any directory") deprecated KBUILD_SRCTREE. It is only used in tools/testing/selftest/ to distinguish out-of-tree build. Replace it with a new boolean flag, building_out_of_srctree. I also replaced the conditional ($(srctree),.) because the next commit will allow an absolute path to be used for $(srctree) even when building in the source tree. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-09kbuild: support header-test-pattern-yMasahiro Yamada1-0/+11
In my view, most of headers can be self-contained. So, it would be tedious to add every header to header-test-y explicitly. We usually end up with "all headers with some exceptions". There are two types in exceptions: [1] headers that are never compiled as standalone units For examples, include/linux/compiler-gcc.h is not intended for direct inclusion. We should always exclude such ones. [2] headers that are conditionally compiled as standalone units Some headers can be compiled only for particular architectures. For example, include/linux/arm-cci.h can be compiled only for arm/arm64 because it requires <asm/arm-cci.h> to exist. Clang can compile include/soc/nps/mtm.h only for arc because it contains an arch-specific register in inline assembler. So, you can write Makefile like this: header-test- += linux/compiler-gcc.h header-test-$(CONFIG_ARM) += linux/arm-cci.h header-test-$(CONFIG_ARM64) += linux/arm-cci.h header-test-$(CONFIG_ARC) += soc/nps/mtm.h The new syntax header-test-pattern-y will be useful to specify "the rest". The typical usage is like this: header-test-pattern-y += */*.h This will add all the headers in sub-directories to the test coverage, excluding $(header-test-). In this regards, header-test-pattern-y behaves like a weaker variant of header-test-y. Caveat: The patterns in header-test-pattern-y are prefixed with $(srctree)/$(src)/ but not $(objtree)/$(obj)/. Stale generated headers are often left over when you traverse the git history without cleaning. Wildcard patterns for $(objtree) may match to stale headers, which could fail to compile. One pitfall is $(srctree)/$(src)/ and $(objtree)/$(obj)/ point to the same directory for in-tree building. So, header-test-pattern-y should be used with care since it can potentially match to stale headers. Caveat2: You could use wildcard for header-test-. For example, header-test- += asm-generic/% ... will exclude headers in asm-generic directory. Unfortunately, the wildcard character is '%' instead of '*' here because this is evaluated by $(filter-out ...) whereas header-test-pattern-y is evaluated by $(wildcard ...). This is a kludge, but seems useful in some places... Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Jani Nikula <jani.nikula@intel.com>
2019-07-09kbuild: do not create wrappers for header-test-yMasahiro Yamada1-1/+1
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>
2019-06-15kbuild: add support for ensuring headers are self-containedJani Nikula1-0/+3
Sometimes it's useful to be able to explicitly ensure certain headers remain self-contained, i.e. that they are compilable as standalone units, by including and/or forward declaring everything they depend on. Add special target header-test-y where individual Makefiles can add headers to be tested if CONFIG_HEADER_TEST is enabled. This will generate a dummy C file per header that gets built as part of extra-y. Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-22dt-bindings: Pass binding directory to validation toolsRob Herring1-1/+1
In order to have $ref's to schema files within the kernel, we need to pass the base path of bindings to the schema validation tools. Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: devicetree@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Signed-off-by: Rob Herring <robh@kernel.org>
2019-05-18kbuild: remove 'addtree' and 'flags' magic for header search pathsMasahiro Yamada1-18/+8
The 'addtree' and 'flags' in scripts/Kbuild.include are so compilecated and ugly. As I mentioned in [1], Kbuild should stop automatic prefixing of header search path options. I fixed up (almost) all Makefiles in the kernel. Now 'addtree' and 'flags' have been removed. Kbuild still caters to add $(srctree)/$(src) and $(objtree)/$(obj) to the header search path for O= building, but never touches extra compiler options from ccflags-y etc. [1]: https://patchwork.kernel.org/patch/9632347/ Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-04-02kbuild: use $(srctree) instead of KBUILD_SRC to check out-of-tree buildMasahiro Yamada1-1/+1
KBUILD_SRC was conventionally used for some different purposes: [1] To remember the source tree path [2] As a flag to check if sub-make is already done [3] As a flag to check if Kbuild runs out of tree For [1], we do not need to remember it because the top Makefile can compute it by $(realpath $(dir $(lastword $(MAKEFILE_LIST)))) [2] has been replaced with self-commenting 'sub_make_done'. For [3], we can distinguish in-tree/out-of-tree by comparing $(srctree) and '.' This commit converts [3] to prepare for the KBUILD_SRC removal. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-03-13kbuild: move archive command to scripts/Makefile.libMasahiro Yamada1-0/+6
scripts/Makefile.build and arch/s390/boot/Makefile use the same command (thin archiving with symbol table creation). Avoid the code duplication, and move it to scripts/Makefile.lib. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-01-28kbuild: remove unnecessary in-subshell executionMasahiro Yamada1-11/+10
The commands surrounded by ( ) are executed in a subshell, but in most cases, we do not need to spawn an extra subshell. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-01-28kbuild: add real-prereqs shorthand for $(filter-out FORCE,$^)Masahiro Yamada1-9/+9
In Kbuild, if_changed and friends must have FORCE as a prerequisite. Hence, $(filter-out FORCE,$^) or $(filter-out $(PHONY),$^) is a common idiom to get the names of all the prerequisites except phony targets. Add real-prereqs as a shorthand. Note: We cannot replace $(filter %.o,$^) in cmd_link_multi-m because $^ may include auto-generated dependencies from the .*.cmd file when a single object module is changed into a multi object module. Refer to commit 69ea912fda74 ("kbuild: remove unneeded link_multi_deps"). I added some comment to avoid accidental breakage. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Rob Herring <robh@kernel.org>
2019-01-28kbuild: simplify rules of data compression with size appendingMasahiro Yamada1-11/+7
All the callers of size_append pass $(filter-out FORCE,$^). Move $(filter-out FORCE,$^) to the definition of size_append. This makes the callers cleaner because $(call ...) is unneeded for a macro with no argument. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-01-28kbuild: skip 'addtree' and 'flags' magic for external module buildMasahiro Yamada1-5/+6
When building an external module, $(obj) is the absolute path to it. The header search paths from ccflags-y etc. should not be tweaked. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-01-06kbuild: change filechk to surround the given command with { }Masahiro Yamada1-2/+1
filechk_* rules often consist of multiple 'echo' lines. They must be surrounded with { } or ( ) to work correctly. Otherwise, only the string from the last 'echo' would be written into the target. Let's take care of that in the 'filechk' in scripts/Kbuild.include to clean up filechk_* rules. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-01-06kbuild: remove redundant target cleaning on failureMasahiro Yamada1-14/+7
Since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target"), the target file is automatically deleted on failure. The boilerplate code ... || { rm -f $@; false; } is unneeded. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>