kernel/Kbuild.klibc

# ==========================================================================
# Support for building klibc and related programs
# ==========================================================================
#
# To create a kbuild file for a userspace program do the following:
#
# Kbuild:
# 
# user-progs := cat
#
# This will compile a file named cat.c -> the executable 'cat'
# 
# If the user space program consist of more files do the following:
# Kbuild:
#
# user-progs := ipconfig
# ipconfig-y := main.o netdev.c

src := $(obj)

.phony: __build
__build:

# Generic Kbuild routines
include $(srctree)/scripts/Kbuild.include

# Defines used when compiling early userspace (klibc programs)
# ---------------------------------------------------------------------------
KLIBSRC         := usr/klibc

# Arch specific definitions for klibc
include $(KLIBSRC)/arch/$(ARCH)/MCONFIG

USERWARNFLAGS   := -Wall -Wpointer-arith -Wwrite-strings                 \
                   -Wstrict-prototypes -Winline

USERCROSS       := $(CROSS_COMPILE)

USERLD          := $(USERCROSS)ld
USERCC          := $(USERCROSS)gcc
USERAR          := $(USERCROSS)ar
USERRANLIB      := $(USERCROSS)ranlib
USERSTRIP       := $(USERCROSS)strip
USERNM          := $(USERCROSS)nm

USERCPPFLAGS    := -I$(srctree)/usr/include/arch/$(ARCH)                 \
                   -I$(srctree)/usr/include/bits$(BITSIZE)               \
                   -I$(srctree)/usr/include                              \
                   -Iinclude                                             \
                   $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include)   \
                   -D__KLIBC__ -DBITSIZE=$(BITSIZE)
USERCFLAGS      := $(USERCPPFLAGS) $(ARCHREQFLAGS) $(OPTFLAGS)           \
                   $(USERWARNFLAGS)
USERAFLAGS      := -D__ASSEMBLY__ $(USERCPPFLAGS)
USERSTRIPFLAGS  := --strip-all -R .comment -R .note

USERLIBGCC      := $(shell $(USERCC) --print-libgcc)
USERSHAREDFLAGS := $(SHAREDFLAGS)
USERCRT0        := $(objtree)/$(KLIBSRC)/arch/$(ARCH)/crt0.o
USERLIBC        := $(objtree)/$(KLIBSRC)/libc.a

#
# This indicates the location of the final version of the shared library.
# THIS MUST BE AN ABSOLUTE PATH WITH NO FINAL SLASH.
# Leave this empty to make it the root.
#
SHLIBDIR = /lib

export USERLD USERCC USERAR USERSTRIP USERNM
export USERCFLAGS USERAFLAGS USERLIBGCC USERSHAREDFLAGS USERSTRIPFLAGS
export USERCRT0 USERLIBC SHLIBDIR

# kernel configuration
include .config

# Add $(obj)/ for paths that is not absolute
objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))

# Kbuild file in the directory that is being build
include $(obj)/Kbuild

#####
# user-progs := handling

# user-progs based on a single .c file (with same name)
user-single := $(foreach p, $(user-progs), $(if $($(p)-y),,$(p)))

# user-progs which is based on several .o files
user-multi  := $(foreach p, $(user-progs), $(if $($(p)-y),$(p)))
# objects used for user-progs with more then one .o file
user-multi-objs := $(foreach p, $(user-multi), $($(p)-y))
# objects build in this dir
user-real-objs := $(patsubst %/,,$(user-multi-objs))
# Directories we need to visit before user-multi-obs are up-to-date
user-dirs :=  $(patsubst %/,%,$(filter %/, $(user-multi-objs))) 
# replace all dir/ with dir/built-in.o
user-multi-objs := $(patsubst %/, %/built-in.o, $(user-multi-objs))

# $(output-dirs) are a list of directories that contain object files
output-dirs := $(dir $(user-dirs))
output-dirs += $(foreach f, $(hostprogs-y) $(targets), \
               $(if $(dir $(f)), $(dir $(f))))
output-dirs := $(strip $(sort $(filter-out ./,$(output-dirs))))

# prefix so we get full dir
user-progs      := $(addprefix $(obj)/,$(user-progs))
user-single     := $(addprefix $(obj)/,$(user-single))
user-multi      := $(addprefix $(obj)/,$(user-multi))
user-multi-objs := $(addprefix $(obj)/,$(user-multi-objs))
user-real-objs  := $(addprefix $(obj)/,$(user-real-objs))
output-dirs     := $(addprefix $(obj)/,$(output-dirs))
user-dirs       := $(addprefix $(obj)/,$(user-dirs))
subdir-y        := $(addprefix $(obj)/,$(subdir-y))
always          := $(addprefix $(obj)/,$(always))
targets         := $(addprefix $(obj)/,$(targets))


_usercflags    = $(USERCFLAGS) $(EXTRA_USERCFLAGS) $(USERCFLAGS_$(*F).o)
_useraflags    = $(USERAFLAGS) $(EXTRA_USERAFLAGS) $(USERAFLAGS_$(*F).o)

usercflags     = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(_usercflags)
useraflags     = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(_useraflags)

ifneq ($(KBUILD_SRC),)
# Create output directory if not already present
_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))

# Create directories for object files if directory does not exist
# Needed when obj-y := dir/file.o syntax is used
_dummy := $(foreach d,$(output-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
endif

# Do we have to make a built-in.o in this dir?
ifneq ($(strip $(obj-y) $(obj-n) $(obj-)),)
builtin-target := $(obj)/built-in.o
endif

__build: $(subdir-y) $(builtin-target) $(always)
	@:

# Compile C sources (.c)
# ---------------------------------------------------------------------------

quiet_cmd_cc_s_c = USERCC  $@
      cmd_cc_s_c = $(USERCC) $(usercflags) -S -o $@ $< 

%.s: %.c FORCE
	$(call if_changed_dep,cc_s_c)

quiet_cmd_cc_i_c = USERCPP $@
      cmd_cc_i_c = $(USERCPP) $(usercflags)   -o $@ $<

%.i: %.c FORCE
	$(call if_changed_dep,cc_i_c)

quiet_cmd_cc_o_c = USERCC  $@
      cmd_cc_o_c = $(USERCC) $(usercflags) -c -o $@ $<

%.o: %.c FORCE
	$(call if_changed_dep,cc_o_c)

# Compile assembler sources (.S)
# ---------------------------------------------------------------------------

quiet_cmd_as_s_S = USERCPP $@
      cmd_as_s_S = $(USERCPP) $(useraflags)   -o $@ $< 

%.s: %.S FORCE
	$(call if_changed_dep,as_s_S)

quiet_cmd_as_o_S = USERAS  $@
      cmd_as_o_S = $(USERCC) $(useraflags) -c -o $@ $<

%.o: %.S FORCE
	$(call if_changed_dep,as_o_S)

targets += $(real-objs-y)

#
# Rule to compile a set of .o files into one .o file
#
ifdef builtin-target
quiet_cmd_link_o_target = LD      $@
# If the list of objects to link is empty, just create an empty built-in.o
cmd_link_o_target = $(if $(strip $(obj-y)),\
                    $(USERLD) $(USERLDFLAGS) -r -o $@ $(filter $(obj-y), $^),\
                    rm -f $@; $(AR) rcs $@)

$(builtin-target): $(obj-y) FORCE
	$(call if_changed,link_o_target)
targets += $(builtin-target)
endif # builtin-target


ifdef user-progs
# Compile userspace programs for the target
# ===========================================================================

__build : $(user-dirs) $(user-progs)

# Descend if needed
$(sort $(addsuffix /built-in.o,$(user-dirs))): $(user-dirs) ;

quiet_cmd_user-ld-single = USERLD  $@
      cmd_user-ld-single = $(USERLD) $(USERLDFLAGS) -o $@      \
                           $(USERCRT0) $<                      \
                           $(filter-out FORCE,$^)              \
                           $(USERLIBC) $(USERLIBGCC)           \
                           $(USERLIBGCC);                      \
                           $(USERSTRIP) $(USERSTRIPFLAGS) $@

$(user-single): %: %.o $(USERCRT0) $(USERLIBC) FORCE
	$(call if_changed,user-ld-single)

targets += $(user-single) $(user-single:=.o)

multi-deps = $($(subst $(obj)/,,$@-y))
link-multi-deps = $(addprefix $(obj)/, \
                    $(patsubst %/, %/built-in.o, $(multi-deps)))

quiet_cmd_user-ld-multi = USERLD  $@
      cmd_user-ld-multi = $(USERLD) $(USERLDFLAGS) -o $@       \
                           $(USERCRT0)                         \
                           $(link-multi-deps)                  \
                           $(USERLIBC) $(USERLIBGCC)           \
                           $(USERLIBGCC);                      \
                           $(USERSTRIP) $(USERSTRIPFLAGS) $@

$(user-multi): $(user-multi-objs) FORCE
	$(call if_changed,user-ld-multi)

targets += $(user-multi) $(user-real-objs)
endif


# Compile programs on the host
# ===========================================================================
ifdef hostprogs-y
include $(srctree)/scripts/Makefile.host
endif

# Descending
# ---------------------------------------------------------------------------

.PHONY: $(subdir-y) $(user-dirs)
$(subdir-y) $(user-dirs):
	$(Q)$(MAKE) $(klibc)=$@

# Add FORCE to the prequisites of a target to force it to be always rebuilt.
# ---------------------------------------------------------------------------

.PHONY: FORCE

FORCE:

# Linking
# Create a reloctable composite object file
# ---------------------------------------------------------------------------
quiet_cmd_userld = USERLD  $@
      cmd_userld = $(USERLD) -r $(USERLDFLAGS) \
                                $(EXTRA_USERLDFLAGS) $(USERLDFLAGS_$(@F)) \
                                $(filter-out FORCE,$^) -o $@


# Read all saved command lines and dependencies for the $(targets) we
# may be building above, using $(if_changed{,_dep}). As an
# optimization, we don't need to read them if the target does not
# exist, we will rebuild anyway in that case.

targets := $(wildcard $(sort $(targets)))
cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))

ifneq ($(cmd_files),)
  include $(cmd_files)
endif

# Shorthand for $(Q)$(MAKE) -f scripts/Kbuild.klibc obj
# Usage:
# $(Q)$(MAKE) $(klibc)=dir
klibc := -rR -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Kbuild.klibc obj