Commit 3b24b837 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'kbuild-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild 

Pull Kbuild updates from Masahiro Yamada:

 - add a shell script to get Clang version

 - improve portability of build scripts

 - drop always-enabled CONFIG_THIN_ARCHIVE and remove unused code

 - rename built-in.o which is now thin archive to built-in.a

 - process clean/build targets one by one to get along with -j option

 - simplify ld-option

 - improve building with CONFIG_TRIM_UNUSED_KSYMS

 - define KBUILD_MODNAME even for objects shared among multiple modules

 - avoid linking multiple instances of same objects from composite
   objects

 - move <linux/compiler_types.h> to c_flags to include it only for C
   files

 - clean-up various Makefiles

* tag 'kbuild-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (29 commits)
  kbuild: get <linux/compiler_types.h> out of <linux/kconfig.h>
  kbuild: clean up link rule of composite modules
  kbuild: clean up archive rule of built-in.a
  kbuild: remove partial section mismatch detection for built-in.a
  net: liquidio: clean up Makefile for simpler composite object handling
  lib: zstd: clean up Makefile for simpler composite object handling
  kbuild: link $(real-obj-y) instead of $(obj-y) into built-in.a
  kbuild: rename real-objs-y/m to real-obj-y/m
  kbuild: move modname and modname-multi close to modname_flags
  kbuild: simplify modname calculation
  kbuild: fix modname for composite modules
  kbuild: define KBUILD_MODNAME even if multiple modules share objects
  kbuild: remove unnecessary $(subst $(obj)/, , ...) in modname-multi
  kbuild: Use ls(1) instead of stat(1) to obtain file size
  kbuild: link vmlinux only once for CONFIG_TRIM_UNUSED_KSYMS
  kbuild: move include/config/ksym/* to include/ksym/*
  kbuild: move CONFIG_TRIM_UNUSED_KSYMS code unneeded for external module
  kbuild: restore autoksyms.h touch to the top Makefile
  kbuild: move 'scripts' target below
  kbuild: remove wrong 'touch' in adjust_autoksyms.sh
  ...
parents 0734e00e a95b37e2

.gitignore

+1 −0
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ modules.builtin 
#

include/config

include/generated

include/ksym

arch/*/include/generated



# stgit generated dirs

Documentation/kbuild/kbuild.txt

+0 −4
Original line number Diff line number Diff line
@@ -50,10 +50,6 @@ LDFLAGS_MODULE 
--------------------------------------------------

Additional options used for $(LD) when linking modules.



LDFLAGS_vmlinux

--------------------------------------------------

Additional options passed to final link of vmlinux.



KBUILD_VERBOSE

--------------------------------------------------

Set the kbuild verbosity. Can be assigned same values as "V=...".

Documentation/kbuild/makefiles.txt

+14 −14
Original line number Diff line number Diff line
@@ -153,12 +153,18 @@ more details, with real examples. 
	configuration.



	Kbuild compiles all the $(obj-y) files.  It then calls

	"$(LD) -r" to merge these files into one built-in.o file.

	built-in.o is later linked into vmlinux by the parent Makefile.

	"$(AR) rcSTP" to merge these files into one built-in.a file.

	This is a thin archive without a symbol table, which makes it

	unsuitable as a linker input.



	The scripts/link-vmlinux.sh script later makes an aggregate

	built-in.a with "${AR} rcsTP", which creates the thin archive

	with a symbol table and an index, making it a valid input for

	the final vmlinux link passes.



	The order of files in $(obj-y) is significant.  Duplicates in

	the lists are allowed: the first instance will be linked into

	built-in.o and succeeding instances will be ignored.

	built-in.a and succeeding instances will be ignored.



	Link order is significant, because certain functions

	(module_init() / __initcall) will be called during boot in the
@@ -222,7 +228,7 @@ more details, with real examples. 
	Note: Of course, when you are building objects into the kernel,

	the syntax above will also work. So, if you have CONFIG_EXT2_FS=y,

	kbuild will build an ext2.o file for you out of the individual

	parts and then link this into built-in.o, as you would expect.

	parts and then link this into built-in.a, as you would expect.



--- 3.4 Objects which export symbols
@@ -232,7 +238,7 @@ more details, with real examples. 
--- 3.5 Library file goals - lib-y



	Objects listed with obj-* are used for modules, or

	combined in a built-in.o for that specific directory.

	combined in a built-in.a for that specific directory.

	There is also the possibility to list objects that will

	be included in a library, lib.a.

	All objects listed with lib-y are combined in a single
@@ -244,7 +250,7 @@ more details, with real examples. 


	Note that the same kbuild makefile may list files to be built-in

	and to be part of a library. Therefore the same directory

	may contain both a built-in.o and a lib.a file.

	may contain both a built-in.a and a lib.a file.



	Example:

		#arch/x86/lib/Makefile
@@ -831,12 +837,6 @@ When kbuild executes, the following steps are followed (roughly): 
	Note: ldflags-y can be used to further customise

	the flags used. See chapter 3.7.



    LDFLAGS_MODULE	Options for $(LD) when linking modules



	LDFLAGS_MODULE is used to set specific flags for $(LD) when

	linking the .ko files used for modules.

	Default is "-r", for relocatable output.



    LDFLAGS_vmlinux	Options for $(LD) when linking vmlinux



	LDFLAGS_vmlinux is used to specify additional flags to pass to
@@ -986,7 +986,7 @@ When kbuild executes, the following steps are followed (roughly): 


	$(head-y) lists objects to be linked first in vmlinux.

	$(libs-y) lists directories where a lib.a archive can be located.

	The rest list directories where a built-in.o object file can be

	The rest list directories where a built-in.a object file can be

	located.



	$(init-y) objects will be located after $(head-y).
@@ -1071,7 +1071,7 @@ When kbuild executes, the following steps are followed (roughly): 
		extra-y := head.o init_task.o



	In this example, extra-y is used to list object files that

	shall be built, but shall not be linked as part of built-in.o.

	shall be built, but shall not be linked as part of built-in.a.





--- 6.7 Commands useful for building a boot image

Documentation/process/changes.rst

+1 −1
Original line number Diff line number Diff line
@@ -78,7 +78,7 @@ Binutils 
--------



The build system has, as of 4.13, switched to using thin archives (`ar T`)

rather than incremental linking (`ld -r`) for built-in.o intermediate steps.

rather than incremental linking (`ld -r`) for built-in.a intermediate steps.

This requires binutils 2.20 or newer.



Flex

Makefile

+49 −40
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ unexport GREP_OPTIONS 
# Most importantly: sub-Makefiles should only ever modify files in

# their own directory. If in some directory we have a dependency on

# a file in another dir (which doesn't happen often, but it's often

# unavoidable when linking the built-in.o targets which finally

# unavoidable when linking the built-in.a targets which finally

# turn into vmlinux), we will call a sub make in that other dir, and

# after that we are sure that everything which is in that other dir

# is now up to date.
@@ -220,7 +220,8 @@ export srctree objtree VPATH 
version_h := include/generated/uapi/linux/version.h

old_version_h := include/linux/version.h



no-dot-config-targets := clean mrproper distclean \

clean-targets := %clean mrproper cleandocs

no-dot-config-targets := $(clean-targets) \

			 cscope gtags TAGS tags help% %docs check% coccicheck \

			 $(version_h) headers_% archheaders archscripts \

			 kernelversion %src-pkg
@@ -243,6 +244,14 @@ ifeq ($(KBUILD_EXTMOD),) 
                endif

        endif

endif



# For "make -j clean all", "make -j mrproper defconfig all", etc.

ifneq ($(filter $(clean-targets),$(MAKECMDGOALS)),)

        ifneq ($(filter-out $(clean-targets),$(MAKECMDGOALS)),)

                mixed-targets := 1

        endif

endif



# install and modules_install need also be processed one by one

ifneq ($(filter install,$(MAKECMDGOALS)),)

        ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
@@ -418,6 +427,7 @@ KBUILD_CFLAGS_KERNEL := 
KBUILD_AFLAGS_MODULE  := -DMODULE

KBUILD_CFLAGS_MODULE  := -DMODULE

KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds

LDFLAGS :=

GCC_PLUGINS_CFLAGS :=



export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
@@ -556,14 +566,6 @@ endif 
export KBUILD_MODULES KBUILD_BUILTIN



ifeq ($(KBUILD_EXTMOD),)

# Additional helpers built in scripts/

# Carefully list dependencies so we do not try to build scripts twice

# in parallel

PHONY += scripts

scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \

	 asm-generic gcc-plugins

	$(Q)$(MAKE) $(build)=$(@)



# Objects we will link into vmlinux / subdirs we need to visit

init-y		:= init/

drivers-y	:= drivers/ sound/ firmware/
@@ -611,13 +613,6 @@ else 
include/config/auto.conf: ;

endif # $(dot-config)



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

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

# (this can be evaluated only once include/config/auto.conf has been included)

ifdef CONFIG_TRIM_UNUSED_KSYMS

  KBUILD_MODULES := 1

endif



# The all: target is the default when no target is given on the

# command line.

# This allow a user to issue only 'make' to build a kernel including modules
@@ -984,13 +979,13 @@ vmlinux-dirs := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \ 
vmlinux-alldirs	:= $(sort $(vmlinux-dirs) $(patsubst %/,%,$(filter %/, \

		     $(init-) $(core-) $(drivers-) $(net-) $(libs-) $(virt-))))



init-y		:= $(patsubst %/, %/built-in.o, $(init-y))

core-y		:= $(patsubst %/, %/built-in.o, $(core-y))

drivers-y	:= $(patsubst %/, %/built-in.o, $(drivers-y))

net-y		:= $(patsubst %/, %/built-in.o, $(net-y))

init-y		:= $(patsubst %/, %/built-in.a, $(init-y))

core-y		:= $(patsubst %/, %/built-in.a, $(core-y))

drivers-y	:= $(patsubst %/, %/built-in.a, $(drivers-y))

net-y		:= $(patsubst %/, %/built-in.a, $(net-y))

libs-y1		:= $(patsubst %/, %/lib.a, $(libs-y))

libs-y2		:= $(filter-out %.a, $(patsubst %/, %/built-in.o, $(libs-y)))

virt-y		:= $(patsubst %/, %/built-in.o, $(virt-y))

libs-y2		:= $(patsubst %/, %/built-in.a, $(filter-out %.a, $(libs-y)))

virt-y		:= $(patsubst %/, %/built-in.a, $(virt-y))



# Externally visible symbols (used by link-vmlinux.sh)

export KBUILD_VMLINUX_INIT := $(head-y) $(init-y)
@@ -1003,25 +998,26 @@ export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Doc 


vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN) $(KBUILD_VMLINUX_LIBS)



# Include targets which we want to execute sequentially if the rest of the

# kernel build went well. If CONFIG_TRIM_UNUSED_KSYMS is set, this might be

# evaluated more than once.

PHONY += vmlinux_prereq

vmlinux_prereq: $(vmlinux-deps) FORCE

ifdef CONFIG_HEADERS_CHECK

	$(Q)$(MAKE) -f $(srctree)/Makefile headers_check

endif

ifdef CONFIG_GDB_SCRIPTS

	$(Q)ln -fsn $(abspath $(srctree)/scripts/gdb/vmlinux-gdb.py)

endif

# Recurse until adjust_autoksyms.sh is satisfied

PHONY += autoksyms_recursive

autoksyms_recursive: $(vmlinux-deps)

ifdef CONFIG_TRIM_UNUSED_KSYMS

	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \

	  "$(MAKE) -f $(srctree)/Makefile vmlinux"

endif



# standalone target for easier testing

include/generated/autoksyms.h: FORCE

	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh true

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

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

# (this can be evaluated only once include/config/auto.conf has been included)

ifdef CONFIG_TRIM_UNUSED_KSYMS

  KBUILD_MODULES := 1

endif



autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h)



$(autoksyms_h):

	$(Q)mkdir -p $(dir $@)

	$(Q)touch $@



ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
@@ -1030,7 +1026,13 @@ cmd_link-vmlinux = \ 
	$(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) ;    \

	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)



vmlinux: scripts/link-vmlinux.sh vmlinux_prereq $(vmlinux-deps) FORCE

vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps) FORCE

ifdef CONFIG_HEADERS_CHECK

	$(Q)$(MAKE) -f $(srctree)/Makefile headers_check

endif

ifdef CONFIG_GDB_SCRIPTS

	$(Q)ln -fsn $(abspath $(srctree)/scripts/gdb/vmlinux-gdb.py)

endif

	+$(call if_changed,link-vmlinux)



# Build samples along the rest of the kernel
@@ -1060,6 +1062,13 @@ endef 
include/config/kernel.release: include/config/auto.conf FORCE

	$(call filechk,kernel.release)



# Additional helpers built in scripts/

# Carefully list dependencies so we do not try to build scripts twice

# in parallel

PHONY += scripts

scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \

	 asm-generic gcc-plugins $(autoksyms_h)

	$(Q)$(MAKE) $(build)=$(@)



# Things we need to do before we recursively start building the kernel

# or the modules are listed in "prepare".
@@ -1088,7 +1097,7 @@ endif 
# that need to depend on updated CONFIG_* values can be checked here.

prepare2: prepare3 prepare-compiler-check outputmakefile asm-generic



prepare1: prepare2 $(version_h) include/generated/utsrelease.h \

prepare1: prepare2 $(version_h) $(autoksyms_h) include/generated/utsrelease.h \

                   include/config/auto.conf

	$(cmd_crmodverdir)
@@ -1327,7 +1336,7 @@ endif # CONFIG_MODULES 
# make distclean Remove editor backup files, patch leftover files and the like



# Directories & files removed with 'make clean'

CLEAN_DIRS  += $(MODVERDIR)

CLEAN_DIRS  += $(MODVERDIR) include/ksym



# Directories & files removed with 'make mrproper'

MRPROPER_DIRS  += include/config usr/include include/generated          \

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