linux-stable/scripts/Makefile.asm-generic
Masahiro Yamada 3204a7fb98 kbuild: prefix $(srctree)/ to some included Makefiles
VPATH is used in Kbuild to make pattern rules search for prerequisites
in both $(objtree) and $(srctree). Some of *.c, *.S files are not real
sources, but generated by tools such as flex, bison, perl.

In contrast, I doubt the benefit of --include-dir=$(abs_srctree) because
it is always clear which Makefiles are real sources, and which are not.

So, my hope is to add $(srctree)/ prefix to all check-in Makefiles,
then remove --include-dir=$(abs_srctree) flag in the future.

I am touching only some Kbuild core parts for now. Treewide fixes will
be needed to achieve this goal.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-03-15 19:20:48 +09:00

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# SPDX-License-Identifier: GPL-2.0
# include/asm-generic contains a lot of files that are used
# verbatim by several architectures.
#
# This Makefile reads the file arch/$(SRCARCH)/include/(uapi/)/asm/Kbuild
# and for each file listed in this file with generic-y creates
# a small wrapper file in arch/$(SRCARCH)/include/generated/(uapi/)/asm.
PHONY := all
all:
src := $(subst /generated,,$(obj))
-include $(src)/Kbuild
# $(generic)/Kbuild lists mandatory-y. Exclude um since it is a special case.
ifneq ($(SRCARCH),um)
include $(srctree)/$(generic)/Kbuild
endif
include $(srctree)/scripts/Kbuild.include
redundant := $(filter $(mandatory-y) $(generated-y), $(generic-y))
redundant += $(foreach f, $(generic-y), $(if $(wildcard $(srctree)/$(src)/$(f)),$(f)))
redundant := $(sort $(redundant))
$(if $(redundant),\
$(warning redundant generic-y found in $(src)/Kbuild: $(redundant)))
# If arch does not implement mandatory headers, fallback to asm-generic ones.
mandatory-y := $(filter-out $(generated-y), $(mandatory-y))
generic-y += $(foreach f, $(mandatory-y), $(if $(wildcard $(srctree)/$(src)/$(f)),,$(f)))
generic-y := $(addprefix $(obj)/, $(generic-y))
generated-y := $(addprefix $(obj)/, $(generated-y))
# Remove stale wrappers when the corresponding files are removed from generic-y
old-headers := $(wildcard $(obj)/*.h)
unwanted := $(filter-out $(generic-y) $(generated-y),$(old-headers))
quiet_cmd_wrap = WRAP $@
cmd_wrap = echo "\#include <asm-generic/$*.h>" > $@
quiet_cmd_remove = REMOVE $(unwanted)
cmd_remove = rm -f $(unwanted)
all: $(generic-y)
$(if $(unwanted),$(call cmd,remove))
@:
$(obj)/%.h:
$(call cmd,wrap)
# Create output directory. Skip it if at least one old header exists
# since we know the output directory already exists.
ifeq ($(old-headers),)
$(shell mkdir -p $(obj))
endif
.PHONY: $(PHONY)