1# SPDX-License-Identifier: GPL-2.0
2# include/asm-generic contains a lot of files that are used
3# verbatim by several architectures.
4#
5# This Makefile reads the file arch/$(SRCARCH)/include/(uapi/)/asm/Kbuild
6# and for each file listed in this file with generic-y creates
7# a small wrapper file in arch/$(SRCARCH)/include/generated/(uapi/)/asm.
8
9PHONY := all
10all:
11
12src := $(subst /generated,,$(obj))
13
14include $(srctree)/scripts/Kbuild.include
15-include $(kbuild-file)
16
17# $(generic)/Kbuild lists mandatory-y. Exclude um since it is a special case.
18ifneq ($(SRCARCH),um)
19include $(srctree)/$(generic)/Kbuild
20endif
21
22redundant := $(filter $(mandatory-y) $(generated-y), $(generic-y))
23redundant += $(foreach f, $(generic-y), $(if $(wildcard $(srctree)/$(src)/$(f)),$(f)))
24redundant := $(sort $(redundant))
25$(if $(redundant),\
26	$(warning redundant generic-y found in $(src)/Kbuild: $(redundant)))
27
28# If arch does not implement mandatory headers, fallback to asm-generic ones.
29mandatory-y := $(filter-out $(generated-y), $(mandatory-y))
30generic-y   += $(foreach f, $(mandatory-y), $(if $(wildcard $(srctree)/$(src)/$(f)),,$(f)))
31
32generic-y   := $(addprefix $(obj)/, $(generic-y))
33generated-y := $(addprefix $(obj)/, $(generated-y))
34
35# Remove stale wrappers when the corresponding files are removed from generic-y
36old-headers := $(wildcard $(obj)/*.h)
37unwanted    := $(filter-out $(generic-y) $(generated-y),$(old-headers))
38
39quiet_cmd_wrap = WRAP    $@
40      cmd_wrap = echo "\#include <asm-generic/$*.h>" > $@
41
42quiet_cmd_remove = REMOVE  $(unwanted)
43      cmd_remove = rm -f $(unwanted)
44
45all: $(generic-y)
46	$(if $(unwanted),$(call cmd,remove))
47	@:
48
49$(obj)/%.h:
50	$(call cmd,wrap)
51
52# Create output directory. Skip it if at least one old header exists
53# since we know the output directory already exists.
54ifeq ($(old-headers),)
55$(shell mkdir -p $(obj))
56endif
57
58.PHONY: $(PHONY)
59