Commit 1bf807b8 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

kbuild: set y instead of 1 to KBUILD_{BUILTIN,MODULES} 



KBUILD_BUILTIN is set to 1 unless you are building only modules.

KBUILD_MODULES is set to 1 when you are building only modules
(a typical use case is "make modules").

It is more useful to set them to 'y' instead, so we can do
something like:

    always-$(KBUILD_BUILTIN) += vmlinux.lds

This works equivalently to:

    extra-y                  += vmlinux.lds

This allows us to deprecate extra-y. extra-y and always-y are quite
similar, and we do not need both.

Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: default avatarNathan Chancellor <nathan@kernel.org>
Reviewed-by: default avatarNicolas Schier <n.schier@avm.de>
parent 481d5c31

Documentation/kbuild/makefiles.rst

+4 −0
Original line number Diff line number Diff line
@@ -291,6 +291,10 @@ Example:: 
  # arch/x86/kernel/Makefile

  extra-y	+= vmlinux.lds



extra-y is now deprecated because this is equivalent to:



  always-$(KBUILD_BUILTIN) += vmlinux.lds



$(extra-y) should only contain targets needed for vmlinux.



Kbuild skips extra-y when vmlinux is apparently not a final goal.

Makefile

+8 −8
Original line number Diff line number Diff line
@@ -749,7 +749,7 @@ targets := 
# Normally, just do built-in.



KBUILD_MODULES :=

KBUILD_BUILTIN := 1

KBUILD_BUILTIN := y



# If we have only "make modules", don't compile built-in objects.

ifeq ($(MAKECMDGOALS),modules)
@@ -761,11 +761,11 @@ endif 
# Just "make" or "make all" shall build modules as well



ifneq ($(filter all modules nsdeps compile_commands.json clang-%,$(MAKECMDGOALS)),)

  KBUILD_MODULES := 1

  KBUILD_MODULES := y

endif



ifeq ($(MAKECMDGOALS),)

  KBUILD_MODULES := 1

  KBUILD_MODULES := y

endif



export KBUILD_MODULES KBUILD_BUILTIN
@@ -1193,7 +1193,7 @@ export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds 
ifdef CONFIG_TRIM_UNUSED_KSYMS

# For the kernel to actually contain only the needed exported symbols,

# we have to build modules as well to determine what those symbols are.

KBUILD_MODULES := 1

KBUILD_MODULES := y

endif



# '$(AR) mPi' needs 'T' to workaround the bug of llvm-ar <= 14
@@ -1533,7 +1533,7 @@ all: modules 
# the built-in objects during the descend as well, in order to

# make sure the checksums are up to date before we record them.

ifdef CONFIG_MODVERSIONS

  KBUILD_BUILTIN := 1

  KBUILD_BUILTIN := y

endif



# Build modules
@@ -1542,7 +1542,7 @@ endif 
# *.ko are usually independent of vmlinux, but CONFIG_DEBUG_INFO_BTF_MODULES

# is an exception.

ifdef CONFIG_DEBUG_INFO_BTF_MODULES

KBUILD_BUILTIN := 1

KBUILD_BUILTIN := y

modules: vmlinux

endif
@@ -1858,7 +1858,7 @@ filechk_kernel.release = echo $(KERNELRELEASE) 


# We are always building only modules.

KBUILD_BUILTIN :=

KBUILD_MODULES := 1

KBUILD_MODULES := y



build-dir := .
@@ -1986,7 +1986,7 @@ endif 


single-goals := $(addprefix $(build-dir)/, $(single-no-ko))



KBUILD_MODULES := 1

KBUILD_MODULES := y



endif