# SPDX-License-Identifier: GPL-2.0 # *DOCUMENTATION* # To see a list of typical targets execute "make help" # More info can be located in ./README # Comments in this file are targeted only to the developer, do not # expect to learn how to build the kernel reading this file. # Do not: # o use make's built-in rules and variables # (this increases performance and avoids hard-to-debug behaviour); # o print "Entering directory ..."; ARCH ?= aarch64 MAKEFLAGS += -rR --no-print-directory # To put more focus on warnings, be less verbose as default # Use 'make V=1' to see the full commands ifeq ("$(origin V)", "command line") KBUILD_VERBOSE = $(V) endif ifndef KBUILD_VERBOSE KBUILD_VERBOSE = 0 endif # kbuild supports saving output files in a separate directory. # To locate output files in a separate directory two syntaxes are supported. # In both cases the working directory must be the root of the kernel src. # 1) O= # Use "make O=dir/to/store/output/files/" # # 2) Set KBUILD_OUTPUT # Set the environment variable KBUILD_OUTPUT to point to the directory # where the output files shall be placed. # export KBUILD_OUTPUT=dir/to/store/output/files/ # make # # The O= assignment takes precedence over the KBUILD_OUTPUT environment # variable. # Our default target PHONY := _all _all: # KBUILD_SRC is set on invocation of make in OBJ directory # KBUILD_SRC is not intended to be used by the regular user (for now) ifeq ($(KBUILD_SRC),) # OK, Make called in directory where kernel src resides # Do we want to locate output files in a separate directory? ifeq ("$(origin O)", "command line") KBUILD_OUTPUT := $(O) endif ifeq ("$(origin W)", "command line") export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W) endif # Cancel implicit rules on top Makefile $(CURDIR)/Makefile Makefile: ; ifneq ($(KBUILD_OUTPUT),) # Invoke a second make in the output directory, passing relevant variables # check that the output directory actually exists saved-output := $(KBUILD_OUTPUT) KBUILD_OUTPUT := $(shell cd $(KBUILD_OUTPUT) && /bin/pwd) $(if $(KBUILD_OUTPUT),, \ $(error output directory "$(saved-output)" does not exist)) PHONY += $(MAKECMDGOALS) sub-make $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make $(Q)@: sub-make: FORCE $(if $(KBUILD_VERBOSE:1=),@)$(MAKE) -C $(KBUILD_OUTPUT) \ KBUILD_SRC=$(CURDIR) \ -f $(CURDIR)/Makefile \ $(filter-out _all sub-make,$(MAKECMDGOALS)) # Leave processing to above invocation of make skip-makefile := 1 endif # ifneq ($(KBUILD_OUTPUT),) endif # ifeq ($(KBUILD_SRC),) # We process the rest of the Makefile if this is the final invocation of make ifeq ($(skip-makefile),) # If building an external module we do not care about the all: rule # but instead _all depend on modules PHONY += all _all: all srctree := $(if $(KBUILD_SRC),$(KBUILD_SRC),$(CURDIR)) objtree := $(CURDIR) src := $(srctree) obj := $(objtree) VPATH := $(srctree) export srctree objtree VPATH CROSS_COMPILE ?= $(CONFIG_CROSS_COMPILE:"%"=%) KERNEL_PATH ?= $(CONFIG_KERNEL_PATH:"%"=%) DT_PATH ?= $(CONFIG_DT_PATH:"%"=%) RAMDISK_PATH ?= $(CONFIG_RAMDISK_PATH:"%"=%) TEXT_BASE ?= $(CONFIG_TEXT_BASE:"%"=%) KCONFIG_CONFIG ?= .config export KCONFIG_CONFIG # SHELL used by kbuild CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \ else if [ -x /bin/bash ]; then echo /bin/bash; \ else echo sh; fi ; fi) HOSTCC = gcc HOSTCXX = g++ HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -Wno-builtin-declaration-mismatch HOSTCXXFLAGS = -O2 # Beautify output # --------------------------------------------------------------------------- # # Normally, we echo the whole command before executing it. By making # that echo $($(quiet)$(cmd)), we now have the possibility to set # $(quiet) to choose other forms of output instead, e.g. # # quiet_cmd_cc_o_c = Compiling $(RELDIR)/$@ # cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< # # If $(quiet) is empty, the whole command will be printed. # If it is set to "quiet_", only the short version will be printed. # If it is set to "silent_", nothing will be printed at all, since # the variable $(silent_cmd_cc_o_c) doesn't exist. # # A simple variant is to prefix commands with $(Q) - that's useful # for commands that shall be hidden in non-verbose mode. # # $(Q)ln $@ :< # # If KBUILD_VERBOSE equals 0 then the above command will be hidden. # If KBUILD_VERBOSE equals 1 then the above command is displayed. ifeq ($(KBUILD_VERBOSE),1) quiet = Q = else quiet=quiet_ Q = @ endif # If the user is running make -s (silent mode), suppress echoing of # commands ifneq ($(findstring s,$(MAKEFLAGS)),) quiet=silent_ endif export quiet Q KBUILD_VERBOSE # Look for make include files relative to root of kernel src MAKEFLAGS += --include-dir=$(srctree) # We need some generic definitions (do not try to remake the file). $(srctree)/scripts/Kbuild.include: ; include $(srctree)/scripts/Kbuild.include # Make variables (CC, etc...) AS = $(CROSS_COMPILE)as LD = $(CROSS_COMPILE)ld CC = $(CROSS_COMPILE)gcc CPP = $(CC) -E AR = $(CROSS_COMPILE)ar NM = $(CROSS_COMPILE)nm STRIP = $(CROSS_COMPILE)strip OBJCOPY = $(CROSS_COMPILE)objcopy OBJDUMP = $(CROSS_COMPILE)objdump AWK = awk INSTALLKERNEL := installkernel PERL = perl CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \ -Wbitwise -Wno-return-void $(CF) CFLAGS_KERNEL = AFLAGS_KERNEL = # Use LINUXINCLUDE when you must reference the include/ directory. # Needed to be compatible with the O= option LINUXINCLUDE := -Iinclude \ $(if $(KBUILD_SRC), -I$(srctree)/include) \ -include include/generated/autoconf.h KBUILD_CPPFLAGS := -D__KERNEL__ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -fno-strict-aliasing -fno-common \ -fno-stack-protector \ -Werror-implicit-function-declaration \ -Wno-format-security \ -fno-delete-null-pointer-checks \ -Wno-builtin-declaration-mismatch -Wno-main -nostdinc \ -I$(srctree)/lib/unic KBUILD_AFLAGS_KERNEL := KBUILD_CFLAGS_KERNEL := KBUILD_AFLAGS := -D__ASSEMBLY__ # Read KERNELRELEASE from include/config/kernel.release (if it exists) KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null) KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION) export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC export CPP AR NM STRIP OBJCOPY OBJDUMP export MAKE AWK GENKSYMS INSTALLKERNEL PERL UTS_MACHINE export HOSTCXX HOSTCXXFLAGS export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS LDFLAGS export KBUILD_CFLAGS CFLAGS_KERNEL export KBUILD_AFLAGS AFLAGS_KERNEL export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL export KBUILD_ARFLAGS # Files to ignore in find ... statements RCS_FIND_IGNORE := \( -name SCCS -o -name BitKeeper -o -name .svn -o -name CVS -o -name .pc -o -name .hg -o -name .git \) -prune -o # =========================================================================== # Rules shared between *config targets and build targets # Basic helpers built in scripts/ PHONY += scripts_basic scripts_basic: $(Q)$(MAKE) $(build)=scripts/basic # To avoid any implicit rule to kick in, define an empty command. scripts/basic/%: scripts_basic ; PHONY += outputmakefile # outputmakefile generates a Makefile in the output directory, if using a # separate output directory. This allows convenient use of make in the # output directory. outputmakefile: ifneq ($(KBUILD_SRC),) $(Q)ln -fsn $(srctree) source $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile \ $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL) endif # To make sure we do not include .config for any of the *config targets # catch them early, and hand them over to scripts/kconfig/Makefile # It is allowed to specify more targets when calling make, including # mixing *config targets and build targets. # For example 'make oldconfig all'. # Detect when mixed targets is specified, and make a second invocation # of make so .config is not included in this case either (for *config). no-dot-config-targets := clean mrproper distclean \ cscope gtags TAGS tags help %docs check% coccicheck \ include/linux/version.h headers_% \ kernelversion %src-pkg config-targets := 0 mixed-targets := 0 dot-config := 1 ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),) ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),) dot-config := 0 endif endif ifneq ($(filter config %config,$(MAKECMDGOALS)),) config-targets := 1 ifneq ($(filter-out config %config,$(MAKECMDGOALS)),) mixed-targets := 1 endif endif ifeq ($(mixed-targets),1) # =========================================================================== # We're called with mixed targets (*config and build targets). # Handle them one by one. %:: FORCE $(Q)$(MAKE) -C $(srctree) KBUILD_SRC= $@ else ifeq ($(config-targets),1) # =========================================================================== # *config targets only - make sure prerequisites are updated, and descend # in scripts/kconfig to make the *config target # Read arch specific Makefile to set KBUILD_DEFCONFIG as needed. # KBUILD_DEFCONFIG may point out an alternative default configuration # used for 'make defconfig' #include $(srctree)/arch/$(SRCARCH)/Makefile export KBUILD_DEFCONFIG KBUILD_KCONFIG config: scripts_basic outputmakefile FORCE $(Q)mkdir -p include/linux include/config $(Q)$(MAKE) $(build)=scripts/kconfig $@ %config: scripts_basic outputmakefile FORCE $(Q)mkdir -p include/linux include/config $(Q)$(MAKE) $(build)=scripts/kconfig $@ else ifeq ($(dot-config),1) # Read in config -include include/config/auto.conf # Read in dependencies to all Kconfig* files, make sure to run # oldconfig if changes are detected. -include include/config/auto.conf.cmd # To avoid any implicit rule to kick in, define an empty command $(KCONFIG_CONFIG) include/config/auto.conf.cmd: ; # If .config is newer than include/config/auto.conf, someone tinkered # with it and forgot to run make oldconfig. # if auto.conf.cmd is missing then we are probably in a cleaned tree so # we execute the config step to be sure to catch updated Kconfig files include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig else # Dummy target needed, because used as prerequisite include/config/auto.conf: ; endif # $(dot-config) # The all: target is the default when no target is given on the # command line. # This allow a user to issue only 'make' to build a kernel including modules # Defaults to vmlinux, but the arch makefile usually adds further targets all: arch/$(ARCH)/linker.lds uniLoader # List of main executables main-y := arch/$(ARCH)/start.o \ main/main.o ifeq ($(ARCH), aarch64) arch-libs-y := arch/$(ARCH)/memcpy.o endif # Object directories objs-y := main objs-y += arch # Libraries libs-y := soc libs-y += board libs-y += lib libs-y += drivers uniLoader-dirs := $(objs-y) $(libs-y) uniLoader-objs := $(patsubst %,%/built-in.o, $(objs-y)) uniLoader-libs := $(patsubst %,%/lib.a, $(libs-y)) uniLoader-mains := $(objs-y)/*.o uniLoader-all := $(uniLoader-objs) $(uniLoader-libs) # Do modpost on a prelinked vmlinux. The finally linked vmlinux has # relevant sections renamed as per the linker script. quiet_cmd_uniLoader = LD $@.o cmd_uniLoader = $(LD) $(main-y) $(arch-libs-y) $(uniLoader-libs) -o $@.o --script=arch/$(ARCH)/linker.lds arch/$(ARCH)/linker.lds: arch/$(ARCH)/linker.lds.S $(KERNEL_PATH) $(RAMDISK_PATH) $(CPP) $< -DTEXT_BASE=$(TEXT_BASE) -DKERNEL_PATH=$(KERNEL_PATH) -DDTB_PATH=$(DT_PATH) -DRAMDISK_PATH=$(RAMDISK_PATH) -P -o $@ uniLoader: $(uniLoader-all) $(call if_changed,uniLoader) @echo ' OBJCOPY $@' $(OBJCOPY) -O binary uniLoader.o uniLoader # The actual objects are generated when descending, # make sure no implicit rule kicks in $(sort $(uniLoader-all)): $(uniLoader-dirs) ; # Handle descending into subdirectories listed in $(vmlinux-dirs) # Preset locale variables to speed up the build process. Limit locale # tweaks to this spot to avoid wrong language settings when running # make menuconfig etc. # Error messages still appears in the original language #PHONY += $(vmlinux-dirs) #$(vmlinux-dirs): prepare scripts PHONY += $(uniLoader-dirs) $(uniLoader-dirs): scripts_basic $(Q)$(MAKE) $(build)=$@ ### # Cleaning is done on three levels. # make clean Delete most generated files # Leave enough to build external modules # make mrproper Delete the current configuration, and all generated files # make distclean Remove editor backup files, patch leftover files and the like # Directories & files removed with 'make clean' CLEAN_DIRS += CLEAN_FILES += uniLoader # Directories & files removed with 'make mrproper' MRPROPER_DIRS += include/config include/generated MRPROPER_FILES += .config .config.old tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS # clean - Delete most, but leave enough to build external modules # clean: rm-dirs := $(CLEAN_DIRS) clean: rm-files := $(CLEAN_FILES) clean-dirs := $(addprefix _clean_, $(uniLoader-dirs)) PHONY += $(clean-dirs) clean archclean $(clean-dirs): $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@) clean: $(clean-dirs) $(call cmd,rmdirs) $(call cmd,rmfiles) @find . $(RCS_FIND_IGNORE) \ \( -name '*.[oas]' -o -name '.*.cmd' \ -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' -o -name '*.lds' \ -o -name modules.builtin -o -name '.tmp_*.o.*' \ -o -name '*.gcno' \) -type f -print | xargs rm -f # mrproper - Delete all generated files, including .config # mrproper: rm-dirs := $(wildcard $(MRPROPER_DIRS)) mrproper: rm-files := $(wildcard $(MRPROPER_FILES)) mrproper-dirs := $(addprefix _mrproper_, scripts) PHONY += $(mrproper-dirs) mrproper $(mrproper-dirs): $(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@) mrproper: clean $(mrproper-dirs) $(call cmd,rmdirs) $(call cmd,rmfiles) # distclean # PHONY += distclean distclean: mrproper @find $(srctree) $(RCS_FIND_IGNORE) \ \( -name '*.orig' -o -name '*.rej' -o -name '*~' \ -o -name '*.bak' -o -name '#*#' -o -name '.*.orig' \ -o -name '.*.rej' -o -size 0 \ -o -name '*%' -o -name '.*.cmd' -o -name 'core' \) \ -type f -print | xargs rm -f # FIXME Should go into a make.lib or something # =========================================================================== quiet_cmd_rmdirs = $(if $(wildcard $(rm-dirs)),CLEAN $(wildcard $(rm-dirs))) cmd_rmdirs = rm -rf $(rm-dirs) quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN $(wildcard $(rm-files))) cmd_rmfiles = rm -f $(rm-files) # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=dir # Usage: # $(Q)$(MAKE) $(clean)=dir clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj help: @echo 'Cleaning targets:' @echo ' clean - Remove most generated files but keep the config and' @echo ' enough build support to build external modules' @echo ' mrproper - Remove all generated files + config + various backup files' @echo ' distclean - mrproper + remove editor backup and patch files' @echo '' @echo 'Configuration targets:' @$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help @echo '' @echo 'Other generic targets:' @echo ' all - Build all targets marked with [*]' @echo '* uniLoader - Build the application' @echo ' dir/ - Build all files in dir and below' @echo ' dir/file.[oisS] - Build specified target only' @echo ' dir/file.lst - Build specified mixed source/assembly target only' @echo ' (requires a recent binutils and recent build (System.map))' @echo ' tags/TAGS - Generate tags file for editors' @echo ' cscope - Generate cscope index' @echo ' gtags - Generate GNU GLOBAL index' @echo ' kernelrelease - Output the release version string' @echo ' kernelversion - Output the version stored in Makefile' echo '' @echo 'Static analysers' @echo ' checkstack - Generate a list of stack hogs' @echo ' namespacecheck - Name space analysis on compiled kernel' @echo ' versioncheck - Sanity check on version.h usage' @echo ' includecheck - Check for duplicate included header files' @echo ' export_report - List the usages of all exported symbols' @echo ' headers_check - Sanity check on exported headers' # @$(MAKE) -f $(srctree)/scripts/Makefile.help checker-help @echo '' # @echo 'Kernel packaging:' # @$(MAKE) $(build)=$(package-dir) help @echo '' # @echo 'Documentation targets:' # @$(MAKE) -f $(srctree)/Documentation/DocBook/Makefile dochelp @echo '' @echo ' make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build' @echo ' make V=2 [targets] 2 => give reason for rebuild of target' @echo ' make O=dir [targets] Locate all output files in "dir", including .config' @echo ' make W=n [targets] Enable extra gcc checks, n=1,2,3 where' @echo ' 1: warnings which may be relevant and do not occur too often' @echo ' 2: warnings which occur quite often but may still be relevant' @echo ' 3: more obscure warnings, can most likely be ignored' @echo ' Multiple levels can be combined with W=12 or W=123' @echo ' make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections' @echo '' @echo 'Execute "make" or "make all" to build all targets marked with [*] ' @echo 'For further info see the ./README file' endif #ifeq ($(config-targets),1) endif #ifeq ($(mixed-targets),1) endif # skip-makefile PHONY += FORCE FORCE: # Declare the contents of the .PHONY variable as phony. We keep that # information in a variable so we can use it in if_changed and friends. .PHONY: $(PHONY)