kernel/scripts/Makefile.asm-generic

# 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)