kbuild: use $(abspath ...) instead of $(shell cd ... && /bin/pwd)

Kbuild conventionally uses $(shell cd ... && /bin/pwd) idiom to get
the absolute path of the directory because GNU Make 3.80, the minimal
supported version at that time, did not support $(abspath ...) or
$(realpath ...).

Commit 37d69ee308 ("docs: bump minimal GNU Make version to 3.81")
dropped the GNU Make 3.80 support, so we are now allowed to use those
make-builtin helpers.

This conversion will provide better portability without relying on
the pwd command or its location /bin/pwd.

I am intentionally using $(realpath ...) instead $(abspath ...) in
some places.  The difference between the two is $(realpath ...)
returns an empty string if the given path does not exist.  It is
convenient in places where we need to error-out if the makefile fails
to create an output directory.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Thierry Reding <treding@nvidia.com>
This commit is contained in:
Masahiro Yamada 2017-08-20 15:04:11 +09:00
parent aae4e7a8bc
commit 8e9b466799
4 changed files with 11 additions and 11 deletions

View file

@ -130,8 +130,8 @@ endif
ifneq ($(KBUILD_OUTPUT),)
# check that the output directory actually exists
saved-output := $(KBUILD_OUTPUT)
KBUILD_OUTPUT := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) \
&& /bin/pwd)
$(shell [ -d $(KBUILD_OUTPUT) ] || mkdir -p $(KBUILD_OUTPUT))
KBUILD_OUTPUT := $(realpath $(KBUILD_OUTPUT))
$(if $(KBUILD_OUTPUT),, \
$(error failed to create output directory "$(saved-output)"))
@ -978,7 +978,7 @@ ifdef CONFIG_HEADERS_CHECK
$(Q)$(MAKE) -f $(srctree)/Makefile headers_check
endif
ifdef CONFIG_GDB_SCRIPTS
$(Q)ln -fsn `cd $(srctree) && /bin/pwd`/scripts/gdb/vmlinux-gdb.py
$(Q)ln -fsn $(abspath $(srctree)/scripts/gdb/vmlinux-gdb.py)
endif
ifdef CONFIG_TRIM_UNUSED_KSYMS
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
@ -1237,7 +1237,7 @@ _modinst_:
@rm -rf $(MODLIB)/kernel
@rm -f $(MODLIB)/source
@mkdir -p $(MODLIB)/kernel
@ln -s `cd $(srctree) && /bin/pwd` $(MODLIB)/source
@ln -s $(abspath $(srctree)) $(MODLIB)/source
@if [ ! $(objtree) -ef $(MODLIB)/build ]; then \
rm -f $(MODLIB)/build ; \
ln -s $(CURDIR) $(MODLIB)/build ; \
@ -1629,11 +1629,11 @@ image_name:
# Clear a bunch of variables before executing the submake
tools/: FORCE
$(Q)mkdir -p $(objtree)/tools
$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(shell cd $(objtree) && /bin/pwd) subdir=tools -C $(src)/tools/
$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(src)/tools/
tools/%: FORCE
$(Q)mkdir -p $(objtree)/tools
$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(shell cd $(objtree) && /bin/pwd) subdir=tools -C $(src)/tools/ $*
$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(src)/tools/ $*
# Single targets
# ---------------------------------------------------------------------------

View file

@ -1,6 +1,6 @@
always := gdb-scripts
SRCTREE := $(shell cd $(srctree) && /bin/pwd)
SRCTREE := $(abspath $(srctree))
$(obj)/gdb-scripts:
ifneq ($(KBUILD_SRC),)

View file

@ -26,7 +26,7 @@ endif
ifneq ($(OUTPUT),)
# check that the output directory actually exists
OUTDIR := $(shell cd $(OUTPUT) && /bin/pwd)
OUTDIR := $(realpath $(OUTPUT))
$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
endif

View file

@ -1,7 +1,7 @@
ifneq ($(O),)
ifeq ($(origin O), command line)
dummy := $(if $(shell test -d $(O) || echo $(O)),$(error O=$(O) does not exist),)
ABSOLUTE_O := $(shell cd $(O) ; pwd)
ABSOLUTE_O := $(realpath $(O))
dummy := $(if $(ABSOLUTE_O),,$(error O=$(O) does not exist))
OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/)
COMMAND_O := O=$(ABSOLUTE_O)
ifeq ($(objtree),)
@ -12,7 +12,7 @@ endif
# check that the output directory actually exists
ifneq ($(OUTPUT),)
OUTDIR := $(shell cd $(OUTPUT) && /bin/pwd)
OUTDIR := $(realpath $(OUTPUT))
$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
endif