From d98dba8852592402b67b643015f64b394760daa9 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 28 Apr 2024 00:32:53 +0900 Subject: [PATCH] kbuild: add 'private' to target-specific variables Currently, Kbuild produces inconsistent results in some cases. You can do an interesting experiment using the --shuffle option, which is supported by GNU Make 4.4 or later. Set CONFIG_KVM_INTEL=y and CONFIG_KVM_AMD=m (or vice versa), and repeat incremental builds w/wo --shuffle=reverse. $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s $ make --shuffle=reverse [ snip ] CC [M] arch/x86/kvm/kvm-asm-offsets.s $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s arch/x86/kvm/kvm-asm-offsets.s is rebuilt every time w/wo the [M] marker. arch/x86/kvm/kvm-asm-offsets.s is built as built-in when it is built as a prerequisite of arch/x86/kvm/kvm-intel.o, which is built-in. arch/x86/kvm/kvm-asm-offsets.s is built as modular when it is built as a prerequisite of arch/x86/kvm/kvm-amd.o, which is a module. Another odd example is single target builds. When CONFIG_LKDTM=m, drivers/misc/lkdtm/rodata.o can be built as built-in or modular, depending on how it is built. $ make drivers/misc/lkdtm/lkdtm.o [ snip ] CC [M] drivers/misc/lkdtm/rodata.o $ make drivers/misc/lkdtm/rodata.o [ snip ] CC drivers/misc/lkdtm/rodata.o drivers/misc/lkdtm/rodata.o is built as modular when it is built as a prerequisite of another, but built as built-in when it is a final target. The same thing happens to drivers/memory/emif-asm-offsets.s when CONFIG_TI_EMIF_SRAM=m. $ make drivers/memory/ti-emif-sram.o [ snip ] CC [M] drivers/memory/emif-asm-offsets.s $ make drivers/memory/emif-asm-offsets.s [ snip ] CC drivers/memory/emif-asm-offsets.s This is because the part-of-module=y flag defined for the modules is inherited by its prerequisites. Target-specific variables are likely intended only for local use. This commit adds 'private' to them. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier --- Makefile | 10 +++++----- scripts/Makefile.build | 6 +++--- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/Makefile b/Makefile index b73519492887..81cbe8f0659c 100644 --- a/Makefile +++ b/Makefile @@ -1254,8 +1254,8 @@ define filechk_version.h echo \#define LINUX_VERSION_SUBLEVEL $(SUBLEVEL) endef -$(version_h): PATCHLEVEL := $(or $(PATCHLEVEL), 0) -$(version_h): SUBLEVEL := $(or $(SUBLEVEL), 0) +$(version_h): private PATCHLEVEL := $(or $(PATCHLEVEL), 0) +$(version_h): private SUBLEVEL := $(or $(SUBLEVEL), 0) $(version_h): FORCE $(call filechk,version.h) @@ -1503,7 +1503,7 @@ MRPROPER_FILES += include/config include/generated \ # clean - Delete most, but leave enough to build external modules # -clean: rm-files := $(CLEAN_FILES) +clean: private rm-files := $(CLEAN_FILES) PHONY += archclean vmlinuxclean @@ -1515,7 +1515,7 @@ clean: archclean vmlinuxclean resolve_btfids_clean # mrproper - Delete all generated files, including .config # -mrproper: rm-files := $(MRPROPER_FILES) +mrproper: private rm-files := $(MRPROPER_FILES) mrproper-dirs := $(addprefix _mrproper_,scripts) PHONY += $(mrproper-dirs) mrproper @@ -1792,7 +1792,7 @@ compile_commands.json: $(extmod_prefix)compile_commands.json PHONY += compile_commands.json clean-dirs := $(KBUILD_EXTMOD) -clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \ +clean: private rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \ $(KBUILD_EXTMOD)/compile_commands.json PHONY += prepare diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 43b71c3d0ff6..c9c07a6144eb 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -216,7 +216,7 @@ endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),y) -$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) +$(obj)/%.o: private objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y)) ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi))) @@ -437,8 +437,8 @@ define rule_ld_multi_m $(call cmd,gen_objtooldep) endef -$(multi-obj-m): objtool-enabled := $(delay-objtool) -$(multi-obj-m): part-of-module := y +$(multi-obj-m): private objtool-enabled := $(delay-objtool) +$(multi-obj-m): private part-of-module := y $(multi-obj-m): %.o: %.mod FORCE $(call if_changed_rule,ld_multi_m) $(call multi_depend, $(multi-obj-m), .o, -objs -y -m)