linux/scripts/Makefile.asm-generic, branch master

kbuild: add syscall table generation to scripts/Makefile.asm-headers

2024-07-10T12:23:38Z

There are 11 copies of arch/*/kernel/syscalls/Makefile that all implement the same basic logic in a somewhat awkward way. I tried out various ways of unifying the existing copies and ended up with something that hooks into the logic for generating the redirections to asm-generic headers. This gives a nicer syntax of being able to list the generated files in $(syscall-y) inside of arch/*/include/asm/Kbuild instead of both $(generated-y) in that place and also in another Makefile. The configuration for which syscall.tbl file to use and which ABIs to enable is now done in arch/*/kernel/Makefile.syscalls. I have done patches for all architectures and made sure that the new generic rules implement a superset of all the architecture specific corner cases. ince the header file is not specific to asm-generic/*.h redirects now, I ended up renaming the file to scripts/Makefile.asm-headers. Signed-off-by: Arnd Bergmann

kbuild: verify asm-generic header list

2024-07-10T12:23:38Z

In order to integrate the system call header generation with generating the asm-generic wrappers, restrict the generated headers to those that actually exist in include/asm-generic/. The path is already known, so add these as a dependency. The asm-generic/bugs.h header was removed in commit 61235b24b9cb ("init: Remove check_bugs() leftovers"), which now causes a build failure, so drop it from the list. Signed-off-by: Arnd Bergmann

kbuild: use $(src) instead of $(srctree)/$(src) for source directory

2024-05-09T19:34:52Z

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for checked-in source files. It is merely a convention without any functional difference. In fact, $(obj) and $(src) are exactly the same, as defined in scripts/Makefile.build: src := $(obj) When the kernel is built in a separate output directory, $(src) does not accurately reflect the source directory location. While Kbuild resolves this discrepancy by specifying VPATH=$(srctree) to search for source files, it does not cover all cases. For example, when adding a header search path for local headers, -I$(srctree)/$(src) is typically passed to the compiler. This introduces inconsistency between upstream and downstream Makefiles because $(src) is used instead of $(srctree)/$(src) for the latter. To address this inconsistency, this commit changes the semantics of $(src) so that it always points to the directory in the source tree. Going forward, the variables used in Makefiles will have the following meanings: $(obj) - directory in the object tree $(src) - directory in the source tree (changed by this commit) $(objtree) - the top of the kernel object tree $(srctree) - the top of the kernel source tree Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced with $(src). Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier

kbuild: add kbuild-file macro

2022-11-22T14:40:02Z

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: prefix $(srctree)/ to some included Makefiles

2021-03-15T10:20:48Z

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: force all architectures except um to include mandatory-y

2019-03-17T03:56:32Z

Currently, every arch/*/include/uapi/asm/Kbuild explicitly includes the common Kbuild.asm file. Factor out the duplicated include directives to scripts/Makefile.asm-generic so that no architecture would opt out of the mandatory-y mechanism. um is not forced to include mandatory-y since it is a very exceptional case which does not support UAPI. Signed-off-by: Masahiro Yamada

kbuild: warn redundant generic-y

2019-03-17T03:56:31Z

The generic-y is redundant under the following condition: - arch has its own implementation - the same header is added to generated-y - the same header is added to mandatory-y If a redundant generic-y is found, the warning like follows is displayed: scripts/Makefile.asm-generic:20: redundant generic-y found in arch/arm/include/asm/Kbuild: timex.h I fixed up arch Kbuild files found by this. Suggested-by: Sam Ravnborg Signed-off-by: Masahiro Yamada

kbuild: generate asm-generic wrappers if mandatory headers are missing

2019-01-06T00:46:51Z

Some time ago, Sam pointed out a certain degree of overwrap between generic-y and mandatory-y. (https://lkml.org/lkml/2017/7/10/121) I tweaked the meaning of mandatory-y a little bit; now it defines the minimum set of ASM headers that all architectures must have. If arch does not have specific implementation of a mandatory header, Kbuild will let it fallback to the asm-generic one by automatically generating a wrapper. This will allow to drop lots of redundant generic-y defines. Previously, "mandatory" was used in the context of UAPI, but I guess this can be extended to kernel space ASM headers. Suggested-by: Sam Ravnborg Signed-off-by: Masahiro Yamada Acked-by: Sam Ravnborg

kbuild: refactor Makefile.asm-generic

2018-12-16T15:33:14Z

- Use conventional $(MAKE) $(asm-generic)= style for directory descending - Remove unneeded FORCE since "all" is a phony target - Remove unneeded "_dummy :=" assignment - Skip $(shell mkdir ...) when headers exist in the directory - Misc cleanups Signed-off-by: Masahiro Yamada Acked-by: Sam Ravnborg

Merge tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2017-11-18T01:45:29Z

Pull Kbuild updates from Masahiro Yamada: "One of the most remarkable improvements in this cycle is, Kbuild is now able to cache the result of shell commands. Some variables are expensive to compute, for example, $(call cc-option,...) invokes the compiler. It is not efficient to redo this computation every time, even when we are not actually building anything. Kbuild creates a hidden file ".cache.mk" that contains invoked shell commands and their results. The speed-up should be noticeable. Summary: - Fix arch build issues (hexagon, sh) - Clean up various Makefiles and scripts - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles - Cache variables that are expensive to compute - Improve cc-ldopton and ld-option for Clang - Optimize output directory creation" * tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits) kbuild: move coccicheck help from scripts/Makefile.help to top Makefile sh: decompressor: add shipped files to .gitignore frv: .gitignore: ignore vmlinux.lds selinux: remove unnecessary assignment to subdir- kbuild: specify FORCE in Makefile.headersinst as .PHONY target kbuild: remove redundant mkdir from ./Kbuild kbuild: optimize object directory creation for incremental build kbuild: create object directories simpler and faster kbuild: filter-out PHONY targets from "targets" kbuild: remove redundant $(wildcard ...) for cmd_files calculation kbuild: create directory for make cache only when necessary sh: select KBUILD_DEFCONFIG depending on ARCH kbuild: fix linker feature test macros when cross compiling with Clang kbuild: shrink .cache.mk when it exceeds 1000 lines kbuild: do not call cc-option before KBUILD_CFLAGS initialization kbuild: Cache a few more calls to the compiler kbuild: Add a cache for generated variables kbuild: add forward declaration of default target to Makefile.asm-generic kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE ...