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| author | Masahiro Yamada <masahiroy@kernel.org> | 2022-09-25 03:19:13 +0900 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2022-09-29 06:07:58 +0900 |
| commit | f73edc8951b2de515b5ecc8a357ccd47dd41077e (patch) | |
| tree | d47510e68b59ee420a244941b11be9a189c7e955 /Makefile | |
| parent | 9c5a0ac3c36917c4258f734bda98be02ca36b992 (diff) | |
| download | lwn-f73edc8951b2de515b5ecc8a357ccd47dd41077e.tar.gz lwn-f73edc8951b2de515b5ecc8a357ccd47dd41077e.zip | |
kbuild: unify two modpost invocations
Currently, modpost is executed twice; first for vmlinux, second
for modules.
This commit merges them.
Current build flow
==================
1) build obj-y and obj-m objects
2) link vmlinux.o
3) modpost for vmlinux
4) link vmlinux
5) modpost for modules
6) link modules (*.ko)
The build steps 1) through 6) are serialized, that is, modules are
built after vmlinux. You do not get benefits of parallel builds when
scripts/link-vmlinux.sh is being run.
New build flow
==============
1) build obj-y and obj-m objects
2) link vmlinux.o
3) modpost for vmlinux and modules
4a) link vmlinux
4b) link modules (*.ko)
In the new build flow, modpost is invoked just once.
vmlinux and modules are built in parallel. One exception is
CONFIG_DEBUG_INFO_BTF_MODULES=y, where modules depend on vmlinux.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 32 |
1 files changed, 25 insertions, 7 deletions
@@ -1150,7 +1150,7 @@ cmd_link-vmlinux = \ $(CONFIG_SHELL) $< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)"; \ $(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true) -vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE +vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) modpost FORCE +$(call if_changed_dep,link-vmlinux) targets := vmlinux @@ -1426,7 +1426,13 @@ endif # Build modules # -modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_prepare +# *.ko are usually independent of vmlinux, but CONFIG_DEBUG_INFOBTF_MODULES +# is an exception. +ifdef CONFIG_DEBUG_INFO_BTF_MODULES +modules: vmlinux +endif + +modules: modules_prepare # Target to prepare building external modules modules_prepare: prepare @@ -1739,8 +1745,12 @@ ifdef CONFIG_MODULES $(MODORDER): $(build-dir) @: -modules: modules_check - $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost +# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules. +# This is solely useful to speed up test compiles. +modules: modpost +ifneq ($(KBUILD_MODPOST_NOFINAL),1) + $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal +endif PHONY += modules_check modules_check: $(MODORDER) @@ -1771,6 +1781,11 @@ KBUILD_MODULES := endif # CONFIG_MODULES +PHONY += modpost +modpost: $(if $(single-build),, $(if $(KBUILD_BUILTIN), vmlinux.o)) \ + $(if $(KBUILD_MODULES), modules_check) + $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost + # Single targets # --------------------------------------------------------------------------- # To build individual files in subdirectories, you can do like this: @@ -1790,16 +1805,19 @@ single-ko := $(sort $(filter %.ko, $(MAKECMDGOALS))) single-no-ko := $(filter-out $(single-ko), $(MAKECMDGOALS)) \ $(foreach x, o mod, $(patsubst %.ko, %.$x, $(single-ko))) -$(single-ko): single_modpost +$(single-ko): single_modules @: $(single-no-ko): $(build-dir) @: # Remove MODORDER when done because it is not the real one. -PHONY += single_modpost -single_modpost: $(single-no-ko) modules_prepare +PHONY += single_modules +single_modules: $(single-no-ko) modules_prepare $(Q){ $(foreach m, $(single-ko), echo $(extmod_prefix)$m;) } > $(MODORDER) $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost +ifneq ($(KBUILD_MODPOST_NOFINAL),1) + $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal +endif $(Q)rm -f $(MODORDER) single-goals := $(addprefix $(build-dir)/, $(single-no-ko)) |