1 # SPDX-License-Identifier: GPL-2.0
3 # kbuild: Generic definitions
10 space := $(empty) $(empty)
11 space_escape := _-_SPACE_-_
15 # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
16 dot-target = $(dir $@).$(notdir $@)
19 # The temporary file to save gcc -MD generated dependencies must not
21 depfile = $(subst $(comma),_,$(dot-target).d)
24 # filename of target with directory and extension stripped
25 basetarget = $(basename $(notdir $@))
28 # real prerequisites without phony targets
29 real-prereqs = $(filter-out $(PHONY), $^)
32 # Escape single quote for use in echo statements
33 escsq = $(subst $(squote),'\$(squote)',$1)
36 # Easy method for doing a status message
40 kecho := $($(quiet)kecho)
43 # filechk is used to check if the content of a generated file is updated.
46 # filechk_sample = echo $(KERNELRELEASE)
48 # $(call filechk,sample)
50 # The rule defined shall write to stdout the content of the new file.
51 # The existing file will be compared with the new one.
52 # - If no file exist it is created
53 # - If the content differ the new file is used
54 # - If they are equal no change, and no timestamp update
55 # - stdin is piped in from the first prerequisite ($<) so one has
56 # to specify a valid file as first prerequisite (often the kbuild file)
60 trap "rm -f $(dot-target).tmp" EXIT; \
61 { $(filechk_$(1)); } > $(dot-target).tmp; \
62 if [ ! -r $@ ] || ! cmp -s $@ $(dot-target).tmp; then \
64 mv -f $(dot-target).tmp $@; \
69 # gcc support functions
70 # See documentation in Documentation/kbuild/makefiles.rst
73 # Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
74 # Return first <prefix> where a <prefix>gcc is found in PATH.
75 # If no gcc found in PATH with listed prefixes return nothing
77 # Note: '2>/dev/null' is here to force Make to invoke a shell. Otherwise, it
78 # would try to directly execute the shell builtin 'command'. This workaround
79 # should be kept for a long time since this issue was fixed only after the
80 # GNU Make 4.2.1 release.
81 cc-cross-prefix = $(firstword $(foreach c, $(1), \
82 $(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c))))
84 # output directory for tests below
85 TMPOUT = $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/).tmp_$$$$
88 # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
89 # Exit code chooses option. "$$TMP" serves as a temporary file and is
90 # automatically cleaned up.
91 try-run = $(shell set -e; \
93 TMPO=$(TMPOUT)/tmp.o; \
95 trap "rm -rf $(TMPOUT)" EXIT; \
96 if ($(1)) >/dev/null 2>&1; \
102 # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
104 as-option = $(call try-run,\
105 $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
108 # Usage: cflags-y += $(call as-instr,instr,option1,option2)
110 as-instr = $(call try-run,\
111 printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
114 # Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
115 __cc-option = $(call try-run,\
116 $(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
118 # Do not attempt to build with gcc plugins during cc-option tests.
119 # (And this uses delayed resolution so the flags will be up to date.)
120 CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
123 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
125 cc-option = $(call __cc-option, $(CC),\
126 $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2))
129 # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
130 cc-option-yn = $(call try-run,\
131 $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
134 # Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
135 cc-disable-warning = $(call try-run,\
136 $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
139 # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
140 cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))
143 # Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
144 ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
147 # Note this is mainly for HJ Lu's 3 number binutil versions
148 ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh)
151 # Usage: $(call ld-ifversion, -ge, 22252, y)
152 ld-ifversion = $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) || echo $(4))
157 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
159 # $(Q)$(MAKE) $(build)=dir
160 build := -f $(srctree)/scripts/Makefile.build obj
163 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
165 # $(Q)$(MAKE) $(modbuiltin)=dir
166 modbuiltin := -f $(srctree)/scripts/Makefile.modbuiltin obj
169 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
171 # $(Q)$(MAKE) $(dtbinst)=dir
172 dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
175 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
177 # $(Q)$(MAKE) $(clean)=dir
178 clean := -f $(srctree)/scripts/Makefile.clean obj
181 # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
182 echo-cmd = $(if $($(quiet)cmd_$(1)),\
183 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
185 # sink stdout for 'make -s'
188 silent_redirect := exec >/dev/null;
190 # Delete the target on interruption
192 # GNU Make automatically deletes the target if it has already been changed by
193 # the interrupted recipe. So, you can safely stop the build by Ctrl-C (Make
194 # will delete incomplete targets), and resume it later.
196 # However, this does not work when the stderr is piped to another program, like
197 # $ make >&2 | tee log
198 # Make dies with SIGPIPE before cleaning the targets.
200 # To address it, we clean the target in signal traps.
202 # Make deletes the target when it catches SIGHUP, SIGINT, SIGQUIT, SIGTERM.
203 # So, we cover them, and also SIGPIPE just in case.
205 # Of course, this is unneeded for phony targets.
206 delete-on-interrupt = \
207 $(if $(filter-out $(PHONY), $@), \
208 $(foreach sig, HUP INT QUIT TERM PIPE, \
209 trap 'rm -f $@; trap - $(sig); kill -s $(sig) $$$$' $(sig);))
212 cmd = @set -e; $(echo-cmd) $($(quiet)redirect) $(delete-on-interrupt) $(cmd_$(1))
215 # if_changed - execute command if any prerequisite is newer than
216 # target, or command line has changed
217 # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
218 # including used config symbols
219 # if_changed_rule - as if_changed but execute rule instead
220 # See Documentation/kbuild/makefiles.rst for more info
222 ifneq ($(KBUILD_NOCMDDEP),1)
223 # Check if both commands are the same including their order. Result is empty
224 # string if equal. User may override this check using make KBUILD_NOCMDDEP=1
225 cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
226 $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
228 cmd-check = $(if $(strip $(cmd_$@)),,1)
231 # Replace >$< with >$$< to preserve $ when reloading the .cmd file
233 # Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
235 # Replace >'< with >'\''< to be able to enclose the whole string in '...'
236 # (needed for the shell)
237 make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
239 # Find any prerequisites that is newer than target or that does not exist.
240 # PHONY targets skipped in both cases.
241 any-prereq = $(filter-out $(PHONY),$?)$(filter-out $(PHONY) $(wildcard $^),$^)
243 # Execute command if command has changed or prerequisite(s) are updated.
244 if_changed = $(if $(any-prereq)$(cmd-check), \
246 printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
248 # Execute the command and also postprocess generated .d dependencies file.
249 if_changed_dep = $(if $(any-prereq)$(cmd-check),$(cmd_and_fixdep),@:)
253 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
256 # Usage: $(call if_changed_rule,foo)
257 # Will check if $(cmd_foo) or any of the prerequisites changed,
258 # and if so will execute $(rule_foo).
259 if_changed_rule = $(if $(any-prereq)$(cmd-check),$(rule_$(1)),@:)
262 # why - tell why a target got built
263 # enabled by make V=2
264 # Output (listed in the order they are checked):
265 # (1) - due to target is PHONY
266 # (2) - due to target missing
267 # (3) - due to: file1.h file2.h
268 # (4) - due to command line change
269 # (5) - due to missing .cmd file
270 # (6) - due to target not in $(targets)
271 # (1) PHONY targets are always build
272 # (2) No target, so we better build it
273 # (3) Prerequisite is newer than target
274 # (4) The command line stored in the file named dir/.target.cmd
275 # differed from actual command line. This happens when compiler
277 # (5) No dir/.target.cmd file (used to store command line)
278 # (6) No dir/.target.cmd file and target not listed in $(targets)
279 # This is a good hint that there is a bug in the kbuild file
280 ifeq ($(KBUILD_VERBOSE),2)
282 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
283 $(if $(wildcard $@), \
284 $(if $(any-prereq),- due to: $(any-prereq), \
286 $(if $(cmd_$@),- due to command line change, \
287 $(if $(filter $@, $(targets)), \
288 - due to missing .cmd file, \
289 - due to $(notdir $@) not in $$(targets) \
294 - due to target missing \
298 echo-why = $(call escsq, $(strip $(why)))
301 ###############################################################################
303 # When a Kconfig string contains a filename, it is suitable for
304 # passing to shell commands. It is surrounded by double-quotes, and
305 # any double-quotes or backslashes within it are escaped by
308 # This is no use for dependencies or $(wildcard). We need to strip the
309 # surrounding quotes and the escaping from quotes and backslashes, and
310 # we *do* need to escape any spaces in the string. So, for example:
312 # Usage: $(eval $(call config_filename,FOO))
314 # Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
315 # transformed as described above to be suitable for use within the
318 # Also, if the filename is a relative filename and exists in the source
319 # tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
320 # be prefixed to *both* command invocation and dependencies.
322 # Note: We also print the filenames in the quiet_cmd_foo text, and
323 # perhaps ought to have a version specially escaped for that purpose.
324 # But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
325 # enough. It'll strip the quotes in the common case where there's no
326 # space and it's a simple filename, and it'll retain the quotes when
327 # there's a space. There are some esoteric cases in which it'll print
328 # the wrong thing, but we don't really care. The actual dependencies
329 # and commands *do* get it right, with various combinations of single
330 # and double quotes, backslashes and spaces in the filenames.
332 ###############################################################################
334 define config_filename
335 ifneq ($$(CONFIG_$(1)),"")
336 $(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
337 ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
339 ifeq ($$(wildcard $$($(1)_FILENAME)),)
340 ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
341 $(1)_SRCPREFIX := $(srctree)/
348 ###############################################################################
350 # delete partially updated (i.e. corrupted) files on error
353 # do not delete intermediate files automatically