# 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 print "Entering directory ..."
+MAKEFLAGS += --no-print-directory
+
# We are using a recursive build, so we need to do a little thinking
# to get the ordering right.
#
# descending is started. They are now explicitly listed as the
# prepare rule.
+# To put more focus on warnings, be less verbose as default
+# Use 'make V=1' to see the full commands
+
+ifdef V
+ ifeq ("$(origin V)", "command line")
+ KBUILD_VERBOSE = $(V)
+ endif
+endif
+ifndef KBUILD_VERBOSE
+ KBUILD_VERBOSE = 0
+endif
+
+# Call sparse as part of compilation of C files
+# Use 'make C=1' to enable sparse checking
+
+ifdef C
+ ifeq ("$(origin C)", "command line")
+ KBUILD_CHECKSRC = $(C)
+ endif
+endif
+ifndef KBUILD_CHECKSRC
+ KBUILD_CHECKSRC = 0
+endif
+
+# kbuild supports saving output files in a separate directory.
+# To locate output files in a separate directory two syntax'es are supported.
+# In both cases the working directory must be the root of the kernel src.
+# 1) O=
+# Use "make O=dir/to/store/output/files/"
+#
+# 2) Set KBUILD_OUTPUT
+# Set the environment variable KBUILD_OUTPUT to point to the directory
+# where the output files shall be placed.
+# export KBUILD_OUTPUT=dir/to/store/output/files/
+# make
+#
+# The O= assigment takes precedence over the KBUILD_OUTPUT environment variable.
+
+
+# KBUILD_SRC is set on invocation of make in OBJ directory
+# KBUILD_SRC is not intended to be used by the regular user (for now)
+ifeq ($(KBUILD_SRC),)
+
+# OK, Make called in directory where kernel src resides
+# Do we want to locate output files in a separate directory?
+ifdef O
+ ifeq ("$(origin O)", "command line")
+ KBUILD_OUTPUT := $(O)
+ endif
+endif
+
+ifneq ($(KBUILD_OUTPUT),)
+# Invoke a second make in the output directory, passing relevant variables
+ KBUILD_OUTPUT := $(shell cd $(KBUILD_OUTPUT); /bin/pwd)
+%:
+ @$(MAKE) -C $(KBUILD_OUTPUT) \
+ KBUILD_SRC=$(CURDIR) \
+ KBUILD_VERBOSE=$(KBUILD_VERBOSE) \
+ KBUILD_CHECK=$(KBUILD_CHECK) \
+ -f $(CURDIR)/Makefile $(MAKECMDGOALS)
+
+# Leave processing to above invocation of make
+skip-makefile := 1
+endif # ifneq ($(KBUILD_OUTPUT),)
+endif # ifeq ($(KBUILD_SRC),)
+
+# We process the rest of the Makefile if this is the final invocation of make
+ifeq ($(skip-makefile),)
+
+srctree := $(if $(KBUILD_SRC),$(KBUILD_SRC),.)
+TOPDIR := $(srctree)
+# FIXME - TOPDIR is obsolete, use srctree/objtree
+objtree := $(CURDIR)
+src := $(srctree)
+obj := $(objtree)
+
+VPATH := $(srctree)
+
+export srctree objtree VPATH TOPDIR
+
KERNELRELEASE=$(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
# SUBARCH tells the usermode build what the underlying arch is. That is set
CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
else if [ -x /bin/bash ]; then echo /bin/bash; \
else echo sh; fi ; fi)
-TOPDIR := $(CURDIR)
HOSTCC = gcc
HOSTCXX = g++
KBUILD_MODULES := 1
endif
-export KBUILD_MODULES KBUILD_BUILTIN KBUILD_VERBOSE KBUILD_CHECKSRC
-
-# To put more focus on warnings, less verbose as default
-# Use 'make V=1' to see the full commands
-
-ifdef V
- ifeq ("$(origin V)", "command line")
- KBUILD_VERBOSE = $(V)
- endif
-endif
-ifndef KBUILD_VERBOSE
- KBUILD_VERBOSE = 0
-endif
-
-# Call sparse as part of compilation of C files
-# Use 'make C=1' to enable sparse checking
-
-ifdef C
- ifeq ("$(origin C)", "command line")
- KBUILD_CHECKSRC = $(C)
- endif
-endif
-ifndef KBUILD_CHECKSRC
- KBUILD_CHECKSRC = 0
-endif
-
-# Do not print 'Entering directory ...'
-
-MAKEFLAGS += --no-print-directory
-
-# For maximum performance (+ possibly random breakage, uncomment
-# the following)
-
-#MAKEFLAGS += -rR
+export KBUILD_MODULES KBUILD_BUILTIN KBUILD_VERBOSE
+export KBUILD_CHECKSRC KBUILD_SRC
# Beautify output
# ---------------------------------------------------------------------------
export quiet Q KBUILD_VERBOSE
-# Paths to obj / src tree
+# Look for make include files relative to root of kernel src
+MAKEFLAGS += --include-dir=$(srctree)
-src := .
-obj := .
-srctree := .
-objtree := .
+# For maximum performance (+ possibly random breakage, uncomment
+# the following)
-export srctree objtree
+#MAKEFLAGS += -rR
# Make variables (CC, etc...)
NOSTDINC_FLAGS = -nostdinc -iwithprefix include
-CPPFLAGS := -D__KERNEL__ -Iinclude
+CPPFLAGS := -D__KERNEL__ -Iinclude \
+ $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include)
+
CFLAGS := -Wall -Wstrict-prototypes -Wno-trigraphs -O2 \
-fno-strict-aliasing -fno-common
AFLAGS := -D__ASSEMBLY__
export VERSION PATCHLEVEL SUBLEVEL EXTRAVERSION KERNELRELEASE ARCH \
- CONFIG_SHELL TOPDIR HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC \
+ CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC \
CPP AR NM STRIP OBJCOPY OBJDUMP MAKE AWK GENKSYMS PERL UTS_MACHINE \
HOSTCXX HOSTCXXFLAGS LDFLAGS_BLOB LDFLAGS_MODULE CHECK
# Handle them one by one.
%:: FORCE
- $(Q)$(MAKE) $@
+ $(Q)$(MAKE) -C $(srctree) KBUILD_SRC= $@
else
ifeq ($(config-targets),1)
endif
-include arch/$(ARCH)/Makefile
+include $(srctree)/arch/$(ARCH)/Makefile
# Let architecture Makefiles change CPPFLAGS if needed
CFLAGS := $(CPPFLAGS) $(CFLAGS)
# Handle descending into subdirectories listed in $(SUBDIRS)
.PHONY: $(SUBDIRS)
-$(SUBDIRS): prepare
+$(SUBDIRS): prepare-all
$(Q)$(MAKE) $(build)=$@
-# Things we need done before we descend to build or make
-# module versions are listed in "prepare"
+# Things we need to do before we recursively start building the kernel
+# or the modules are listed in "prepare-all".
+# A multi level approach is used. prepare1 is updated first, then prepare0.
+# prepare-all is the collection point for the prepare targets.
+
+.PHONY: prepare-all prepare prepare0 prepare1
+
+# prepare1 is used to check if we are building in a separate output directory,
+# and if so do:
+# 1) Check that make has not been executed in the kernel src $(srctree)
+# 2) Create the include2 directory, used for the second asm symlink
+
+prepare1:
+ifneq ($(KBUILD_SRC),)
+ @echo ' Using $(srctree) as source for kernel'
+ $(Q)if [ -h $(srctree)/include/asm -o -f $(srctree)/.config ]; then \
+ echo " $(srctree) is not clean, please run 'make mrproper'";\
+ echo " in the '$(srctree)' directory.";\
+ /bin/false; \
+ fi;
+ $(Q)if [ ! -d include2 ]; then mkdir -p include2; fi;
+ $(Q)ln -fsn $(srctree)/include/asm-$(ARCH) include2/asm
+endif
-.PHONY: prepare
-prepare: include/linux/version.h include/asm include/config/MARKER
+prepare0: prepare1 include/linux/version.h include/asm include/config/MARKER
ifdef KBUILD_MODULES
ifeq ($(origin SUBDIRS),file)
$(Q)rm -rf $(MODVERDIR)
endif
$(if $(CONFIG_MODULES),$(Q)mkdir -p $(MODVERDIR))
+# All the preparing..
+prepare-all: prepare0 prepare
+
# Leave this as default for preprocessing vmlinux.lds.S, which is now
# done in arch/$(ARCH)/kernel/Makefile
# before switching between archs anyway.
include/asm:
- @echo ' Making asm->asm-$(ARCH) symlink'
- @ln -s asm-$(ARCH) $@
+ @echo ' SYMLINK $@ -> include/asm-$(ARCH)'
+ $(Q)if [ ! -d include ]; then mkdir -p include; fi;
+ @ln -fsn asm-$(ARCH) $@
# Split autoconf.h into include/linux/config/*
.PHONY: modules
modules: $(SUBDIRS) $(if $(KBUILD_BUILTIN),vmlinux)
@echo ' Building modules, stage 2.';
- $(Q)$(MAKE) -rR -f scripts/Makefile.modpost
+ $(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modpost
# Install modules
@rm -f $(MODLIB)/build
@mkdir -p $(MODLIB)/kernel
@ln -s $(TOPDIR) $(MODLIB)/build
- $(Q)$(MAKE) -rR -f scripts/Makefile.modinst
+ $(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modinst
# If System.map exists, run depmod. This deliberately does not have a
# dependency on System.map since that would run the dependency tree on
$(MODVERDIR) \
.tmp_export-objs \
include/config \
- include/linux/modules
+ include/linux/modules \
+ include2
# clean - Delete all intermediate files
#
echo ' No architecture specific help defined for $(ARCH)')
@echo ''
@echo ' make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
+ @echo ' make O=dir [targets] Locate all output files in "dir", including .config'
@echo ' make C=1 [targets] Check all c source with checker tool'
@echo ''
@echo 'Execute "make" or "make all" to build all targets marked with [*] '
# FIXME Should go into a make.lib or something
# ===========================================================================
-a_flags = -Wp,-MD,$(depfile) $(AFLAGS) $(AFLAGS_KERNEL) $(NOSTDINC_FLAGS) \
+a_flags = -Wp,-MD,$(depfile) $(AFLAGS) $(AFLAGS_KERNEL) \
+ $(NOSTDINC_FLAGS) $(CPPFLAGS) \
$(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(*F).o)
quiet_cmd_as_o_S = AS $@
define filechk
@set -e; \
echo ' CHK $@'; \
+ mkdir -p $(dir $@); \
$(filechk_$(1)) < $< > $@.tmp; \
if [ -r $@ ] && cmp -s $@ $@.tmp; then \
rm -f $@.tmp; \
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=dir
# Usage:
# $(Q)$(MAKE) $(build)=dir
-build := -f scripts/Makefile.build obj
+build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=dir
# Usage:
# $(Q)$(MAKE) $(clean)=dir
-clean := -f scripts/Makefile.clean obj
+clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj
# $(call descend,<dir>,<target>)
# Recursively call a sub-make in <dir> with target <target>
# Usage is deprecated, because make does not see this as an invocation of make.
-descend =$(Q)$(MAKE) -f scripts/Makefile.build obj=$(1) $(2)
+descend =$(Q)$(MAKE) -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj=$(1) $(2)
+
+endif # skip-makefile
FORCE:
# in the local directory
subdir-obj-y := $(foreach o,$(obj-y),$(if $(filter-out $(o),$(notdir $(o))),$(o)))
+# $(obj-dirs) is a list of directories that contain object files
+obj-dirs := $(dir $(multi-objs) $(subdir-obj-y))
+obj-dirs += $(foreach f,$(host-progs), $(if $(dir $(f)),$(dir $(f))))
+obj-dirs := $(strip $(sort $(filter-out ./,$(obj-dirs))))
+
# Replace multi-part objects by their individual parts, look at local dir only
real-objs-y := $(foreach m, $(filter-out $(subdir-obj-y), $(obj-y)), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m))) $(extra-y)
real-objs-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
multi-objs-y := $(addprefix $(obj)/,$(multi-objs-y))
multi-objs-m := $(addprefix $(obj)/,$(multi-objs-m))
subdir-ym := $(addprefix $(obj)/,$(subdir-ym))
+obj-dirs := $(addprefix $(obj)/,$(obj-dirs))
host-progs := $(addprefix $(obj)/,$(host-progs))
host-csingle := $(addprefix $(obj)/,$(host-csingle))
host-cmulti := $(addprefix $(obj)/,$(host-cmulti))
# where foo and bar are the name of the modules.
basename_flags = -DKBUILD_BASENAME=$(subst $(comma),_,$(subst -,_,$(*F)))
modname_flags = $(if $(filter 1,$(words $(modname))),-DKBUILD_MODNAME=$(subst $(comma),_,$(subst -,_,$(modname))))
-c_flags = -Wp,-MD,$(depfile) $(CFLAGS) $(NOSTDINC_FLAGS) \
- $(modkern_cflags) $(EXTRA_CFLAGS) $(CFLAGS_$(*F).o) \
- $(basename_flags) $(modname_flags)
-a_flags = -Wp,-MD,$(depfile) $(AFLAGS) $(NOSTDINC_FLAGS)\
- $(modkern_aflags) $(EXTRA_AFLAGS) $(AFLAGS_$(*F).o)
-hostc_flags = -Wp,-MD,$(depfile) $(HOSTCFLAGS) $(HOST_EXTRACFLAGS)\
- $(HOSTCFLAGS_$(*F).o)
-hostcxx_flags = -Wp,-MD,$(depfile) $(HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS)\
- $(HOSTCXXFLAGS_$(*F).o)
+
+
+_c_flags = $(CFLAGS) $(EXTRA_CFLAGS) $(CFLAGS_$(*F).o)
+_a_flags = $(AFLAGS) $(EXTRA_AFLAGS) $(AFLAGS_$(*F).o)
+_hostc_flags = $(HOSTCFLAGS) $(HOST_EXTRACFLAGS) $(HOSTCFLAGS_$(*F).o)
+_hostcxx_flags = $(HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) $(HOSTCXXFLAGS_$(*F).o)
+
+
+# If building the kernel in a separate objtree expand all occurrences
+# of -Idir to -Idir -I$(srctree)/dir.
+# hereby allowing gcc to locate files in both trees. Local tree first.
+
+ifeq ($(KBUILD_SRC),)
+__c_flags = $(_c_flags)
+__a_flags = $(_a_flags)
+__hostc_flags = $(_hostc_flags)
+__hostcxx_flags = $(_hostcxx_flags)
+else
+flags = $(foreach o,$($(1)),\
+ $(if $(filter -I%,$(o)),$(patsubst -I%,-I$(srctree)/%,$(o)),$(o)))
+
+# -I$(obj) locate generated .h files
+# -I$(srctree)/$(src) locate .h files in srctree, from generated .c files
+# FIXME: Replace both with specific EXTRA_CFLAGS statements
+__c_flags = -I$(obj) -I$(srctree)/$(src) $(call flags,_c_flags)
+__a_flags = $(call flags,_a_flags)
+__hostc_flags = -I$(obj) $(call flags,_hostc_flags)
+__hostcxx_flags = $(call flags,_hostcxx_flags)
+endif
+
+c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(CPPFLAGS) \
+ $(__c_flags) $(modkern_cflags) \
+ $(basename_flags) $(modname_flags)
+
+a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(CPPFLAGS) \
+ $(__a_flags) $(modkern_aflags)
+
+hostc_flags = -Wp,-MD,$(depfile) $(__hostc_flags)
+hostcxx_flags = -Wp,-MD,$(depfile) $(__hostcxx_flags)
+
ld_flags = $(LDFLAGS) $(EXTRA_LDFLAGS)
# Finds the multi-part object the current object will be linked into
# $(call descend,<dir>,<target>)
# Recursively call a sub-make in <dir> with target <target>
# Usage is deprecated, because make do not see this as an invocation of make.
-descend =$(Q)$(MAKE) -f scripts/Makefile.build obj=$(1) $(2)
+descend =$(Q)$(MAKE) -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj=$(1) $(2)
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
# Usage:
# $(Q)$(MAKE) $(build)=dir
-build := -f scripts/Makefile.build obj
+build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj