user/sven/linux.git/scripts/Kbuild.include, branch v5.14.18

kbuild: sink stdout from cmd for silent build

2021-05-26T19:01:50Z

When building with 'make -s', no output to stdout should be printed. As Arnd Bergmann reported [1], mkimage shows the detailed information of the generated images. I think this should be suppressed by the 'cmd' macro instead of by individual scripts. Insert 'exec >/dev/null;' in order to redirect stdout to /dev/null for silent builds. [Note about this implementation] 'exec >/dev/null;' may look somewhat tricky, but this has a reason. Appending '>/dev/null' at the end of command line is a common way for redirection, so I first tried this: cmd = @set -e; $(echo-cmd) $(cmd_$(1)) >/dev/null ... but it would not work if $(cmd_$(1)) itself contains a redirection. For example, cmd_wrap in scripts/Makefile.asm-generic redirects the output from the 'echo' command into the target file. It would be expanded into: echo "#include " > $@ >/dev/null Then, the target file gets empty because the string will go to /dev/null instead of $@. Next, I tried this: cmd = @set -e; $(echo-cmd) { $(cmd_$(1)); } >/dev/null The form above would be expanded into: { echo "#include " > $@; } >/dev/null This works as expected. However, it would be a syntax error if $(cmd_$(1)) is empty. When CONFIG_TRIM_UNUSED_KSYMS is disabled, $(call cmd,gen_ksymdeps) in scripts/Makefile.build would be expanded into: set -e; { ; } >/dev/null ..., which causes an syntax error. I also tried this: cmd = @set -e; $(echo-cmd) ( $(cmd_$(1)) ) >/dev/null ... but this causes a syntax error for the same reason. So, finally I adopted: cmd = @set -e; $(echo-cmd) exec >/dev/null; $(cmd_$(1)) [1]: https://lore.kernel.org/lkml/20210514135752.2910387-1-arnd@kernel.org/ Signed-off-by: Masahiro Yamada

kbuild: split cc-option and friends to scripts/Makefile.compiler

2021-04-24T20:09:32Z

scripts/Kbuild.include is included everywhere, but macros such as cc-option are needed by build targets only. For example, when 'make clean' traverses the tree, it does not need to evaluate $(call cc-option,). Split cc-option, ld-option, etc. to scripts/Makefile.compiler, which is only included from the top Makefile and scripts/Makefile.build. Signed-off-by: Masahiro Yamada

kbuild: remove ld-version macro

2021-02-21T23:22:04Z

There is no direct user of ld-version; you can use CONFIG_LD_VERSION if needed. Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor

kbuild: remove leftover comment for filechk utility

2020-10-20T15:28:53Z

After commit 43fee2b23895 ("kbuild: do not redirect the first prerequisite for filechk"), the rule is no longer automatically passed $< as stdin, so remove the stale comment. Fixes: 43fee2b23895 ("kbuild: do not redirect the first prerequisite for filechk") Signed-off-by: Rasmus Villemoes Signed-off-by: Masahiro Yamada

kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base

2020-08-09T16:32:59Z

Commit d26e94149276 ("kbuild: no gcc-plugins during cc-option tests") was neeeded because scripts/Makefile.gcc-plugins was too early. This is unneeded by including scripts/Makefile.gcc-plugins last, and being careful to not add cc-option tests after it. Signed-off-by: Masahiro Yamada

kbuild: improve cc-option to clean up all temporary files

2020-06-17T01:20:21Z

When cc-option and friends evaluate compiler flags, the temporary file $$TMP is created as an output object, and automatically cleaned up. The actual file path of $$TMP is ..tmp, here is the process ID of $(shell ...) invoked from cc-option. (Please note $$$$ is the escape sequence of $$). Such garbage files are cleaned up in most cases, but some compiler flags create additional output files. For example, -gsplit-dwarf creates a .dwo file. When CONFIG_DEBUG_INFO_SPLIT=y, you will see a bunch of ..dwo files left in the top of build directories. You may not notice them unless you do 'ls -a', but the garbage files will increase every time you run 'make'. This commit changes the temporary object path to .tmp_/tmp, and removes .tmp_ directory when exiting. Separate build artifacts such as *.dwo will be cleaned up all together because their file paths are usually determined based on the base name of the object. Another example is -ftest-coverage, which outputs the coverage data into .gcno Signed-off-by: Masahiro Yamada

kbuild: use -MMD instead of -MD to exclude system headers from dependency

2020-05-12T04:28:33Z

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 . 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 is included from every file. So, I implemented a more reliable way in the previous commit. Signed-off-by: Masahiro Yamada

kbuild: remove *.tmp file when filechk fails

2020-01-15T15:26:22Z

Bartosz Golaszewski reports that when "make {menu,n,g,x}config" fails due to missing packages, a temporary file is left over, which is not ignored by git. For example, if GTK+ is not installed: $ make gconfig * * Unable to find the GTK+ installation. Please make sure that * the GTK+ 2.0 development package is correctly installed. * You need gtk+-2.0 gmodule-2.0 libglade-2.0 * scripts/kconfig/Makefile:208: recipe for target 'scripts/kconfig/gconf-cfg' failed make[1]: *** [scripts/kconfig/gconf-cfg] Error 1 Makefile:567: recipe for target 'gconfig' failed make: *** [gconfig] Error 2 $ git status HEAD detached at v5.4 Untracked files: (use "git add ..." to include in what will be committed) scripts/kconfig/gconf-cfg.tmp nothing added to commit but untracked files present (use "git add" to track) This is because the check scripts are run with filechk, which misses to clean up the temporary file on failure. When the line { $(filechk_$(1)); } > $@.tmp; ... fails, it exits immediately due to the 'set -e'. Use trap to make sure to delete the temporary file on exit. For extra safety, I replaced $@.tmp with $(dot-target).tmp to make it a hidden file. Reported-by: Bartosz Golaszewski Signed-off-by: Masahiro Yamada

kbuild: create modules.builtin without Makefile.modbuiltin or tristate.conf

2020-01-06T17:18:39Z

Commit bc081dd6e9f6 ("kbuild: generate modules.builtin") added infrastructure to generate modules.builtin, the list of all builtin modules. Basically, it works like this: - Kconfig generates include/config/tristate.conf, the list of tristate CONFIG options with a value in a capital letter. - scripts/Makefile.modbuiltin makes Kbuild descend into directories to collect the information of builtin modules. I am not a big fan of it because Kbuild ends up with traversing the source tree twice. I am not sure how perfectly it should work, but this approach cannot avoid false positives; even if the relevant CONFIG option is tristate, some Makefiles forces obj-m to obj-y. Some examples are: arch/powerpc/platforms/powermac/Makefile: obj-$(CONFIG_NVRAM:m=y) += nvram.o net/ipv6/Makefile: obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o net/netlabel/Makefile: obj-$(subst m,y,$(CONFIG_IPV6)) += netlabel_calipso.o Nobody has complained about (or noticed) it, so it is probably fine to have false positives in modules.builtin. This commit simplifies the implementation. Let's exploit the fact that every module has MODULE_LICENSE(). (modpost shows a warning if MODULE_LICENSE is missing. If so, 0-day bot would already have blocked such a module.) I added MODULE_FILE to . When the code is being compiled as builtin, it will be filled with the file path of the module, and collected into modules.builtin.info. Then, scripts/link-vmlinux.sh extracts the list of builtin modules out of it. This new approach fixes the false-positives above, but adds another type of false-positives; non-modular code may have MODULE_LICENSE() by mistake. This is not a big deal, it is just the code is always orphan. We can clean it up if we like. You can see cleanup examples by: $ git log --grep='make.* explicitly non-modular' To sum up, this commits deletes lots of code, but still produces almost equivalent results. Please note it does not increase the vmlinux size at all. As you can see in include/asm-generic/vmlinux.lds.h, the .modinfo section is discarded in the link stage. Signed-off-by: Masahiro Yamada

kbuild: add stringify helper to quote a string passed to C files

2020-01-06T17:18:38Z

Make $(squote)$(quote)...$(quote)$(squote) a helper macro. I will reuse it in the next commit. Signed-off-by: Masahiro Yamada