Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1# SPDX-License-Identifier: GPL-2.0
2####
3# kbuild: Generic definitions
4
5# Convenient variables
6comma := ,
7quote := "
8squote := '
9empty :=
10space := $(empty) $(empty)
11space_escape := _-_SPACE_-_
12pound := \#
13
14###
15# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
16dot-target = $(dir $@).$(notdir $@)
17
18###
19# The temporary file to save gcc -MD generated dependencies must not
20# contain a comma
21depfile = $(subst $(comma),_,$(dot-target).d)
22
23###
24# filename of target with directory and extension stripped
25basetarget = $(basename $(notdir $@))
26
27###
28# real prerequisites without phony targets
29real-prereqs = $(filter-out $(PHONY), $^)
30
31###
32# Escape single quote for use in echo statements
33escsq = $(subst $(squote),'\$(squote)',$1)
34
35###
36# Quote a string to pass it to C files. foo => '"foo"'
37stringify = $(squote)$(quote)$1$(quote)$(squote)
38
39###
40# Easy method for doing a status message
41 kecho := :
42 quiet_kecho := echo
43silent_kecho := :
44kecho := $($(quiet)kecho)
45
46###
47# filechk is used to check if the content of a generated file is updated.
48# Sample usage:
49#
50# filechk_sample = echo $(KERNELRELEASE)
51# version.h: FORCE
52# $(call filechk,sample)
53#
54# The rule defined shall write to stdout the content of the new file.
55# The existing file will be compared with the new one.
56# - If no file exist it is created
57# - If the content differ the new file is used
58# - If they are equal no change, and no timestamp update
59# - stdin is piped in from the first prerequisite ($<) so one has
60# to specify a valid file as first prerequisite (often the kbuild file)
61define filechk
62 $(Q)set -e; \
63 mkdir -p $(dir $@); \
64 trap "rm -f $(dot-target).tmp" EXIT; \
65 { $(filechk_$(1)); } > $(dot-target).tmp; \
66 if [ ! -r $@ ] || ! cmp -s $@ $(dot-target).tmp; then \
67 $(kecho) ' UPD $@'; \
68 mv -f $(dot-target).tmp $@; \
69 fi
70endef
71
72######
73# gcc support functions
74# See documentation in Documentation/kbuild/makefiles.rst
75
76# cc-cross-prefix
77# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
78# Return first <prefix> where a <prefix>gcc is found in PATH.
79# If no gcc found in PATH with listed prefixes return nothing
80#
81# Note: '2>/dev/null' is here to force Make to invoke a shell. Otherwise, it
82# would try to directly execute the shell builtin 'command'. This workaround
83# should be kept for a long time since this issue was fixed only after the
84# GNU Make 4.2.1 release.
85cc-cross-prefix = $(firstword $(foreach c, $(1), \
86 $(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c))))
87
88# output directory for tests below
89TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
90
91# try-run
92# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
93# Exit code chooses option. "$$TMP" serves as a temporary file and is
94# automatically cleaned up.
95try-run = $(shell set -e; \
96 TMP="$(TMPOUT).$$$$.tmp"; \
97 TMPO="$(TMPOUT).$$$$.o"; \
98 if ($(1)) >/dev/null 2>&1; \
99 then echo "$(2)"; \
100 else echo "$(3)"; \
101 fi; \
102 rm -f "$$TMP" "$$TMPO")
103
104# as-option
105# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
106
107as-option = $(call try-run,\
108 $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
109
110# as-instr
111# Usage: cflags-y += $(call as-instr,instr,option1,option2)
112
113as-instr = $(call try-run,\
114 printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
115
116# __cc-option
117# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
118__cc-option = $(call try-run,\
119 $(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
120
121# Do not attempt to build with gcc plugins during cc-option tests.
122# (And this uses delayed resolution so the flags will be up to date.)
123CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
124
125# cc-option
126# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
127
128cc-option = $(call __cc-option, $(CC),\
129 $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2))
130
131# cc-option-yn
132# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
133cc-option-yn = $(call try-run,\
134 $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
135
136# cc-disable-warning
137# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
138cc-disable-warning = $(call try-run,\
139 $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
140
141# cc-ifversion
142# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
143cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))
144
145# ld-option
146# Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
147ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
148
149# ld-version
150# Note this is mainly for HJ Lu's 3 number binutil versions
151ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh)
152
153# ld-ifversion
154# Usage: $(call ld-ifversion, -ge, 22252, y)
155ld-ifversion = $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) || echo $(4))
156
157######
158
159###
160# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
161# Usage:
162# $(Q)$(MAKE) $(build)=dir
163build := -f $(srctree)/scripts/Makefile.build obj
164
165###
166# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
167# Usage:
168# $(Q)$(MAKE) $(dtbinst)=dir
169dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
170
171###
172# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
173# Usage:
174# $(Q)$(MAKE) $(clean)=dir
175clean := -f $(srctree)/scripts/Makefile.clean obj
176
177# echo command.
178# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
179echo-cmd = $(if $($(quiet)cmd_$(1)),\
180 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
181
182# printing commands
183cmd = @set -e; $(echo-cmd) $(cmd_$(1))
184
185###
186# if_changed - execute command if any prerequisite is newer than
187# target, or command line has changed
188# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
189# including used config symbols
190# if_changed_rule - as if_changed but execute rule instead
191# See Documentation/kbuild/makefiles.rst for more info
192
193ifneq ($(KBUILD_NOCMDDEP),1)
194# Check if both commands are the same including their order. Result is empty
195# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
196cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
197 $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
198else
199cmd-check = $(if $(strip $(cmd_$@)),,1)
200endif
201
202# Replace >$< with >$$< to preserve $ when reloading the .cmd file
203# (needed for make)
204# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
205# (needed for make)
206# Replace >'< with >'\''< to be able to enclose the whole string in '...'
207# (needed for the shell)
208make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
209
210# Find any prerequisites that are newer than target or that do not exist.
211# (This is not true for now; $? should contain any non-existent prerequisites,
212# but it does not work as expected when .SECONDARY is present. This seems a bug
213# of GNU Make.)
214# PHONY targets skipped in both cases.
215newer-prereqs = $(filter-out $(PHONY),$?)
216
217# Execute command if command has changed or prerequisite(s) are updated.
218if_changed = $(if $(newer-prereqs)$(cmd-check), \
219 $(cmd); \
220 printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
221
222# Execute the command and also postprocess generated .d dependencies file.
223if_changed_dep = $(if $(newer-prereqs)$(cmd-check),$(cmd_and_fixdep),@:)
224
225cmd_and_fixdep = \
226 $(cmd); \
227 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
228 rm -f $(depfile)
229
230# Usage: $(call if_changed_rule,foo)
231# Will check if $(cmd_foo) or any of the prerequisites changed,
232# and if so will execute $(rule_foo).
233if_changed_rule = $(if $(newer-prereqs)$(cmd-check),$(rule_$(1)),@:)
234
235###
236# why - tell why a target got built
237# enabled by make V=2
238# Output (listed in the order they are checked):
239# (1) - due to target is PHONY
240# (2) - due to target missing
241# (3) - due to: file1.h file2.h
242# (4) - due to command line change
243# (5) - due to missing .cmd file
244# (6) - due to target not in $(targets)
245# (1) PHONY targets are always build
246# (2) No target, so we better build it
247# (3) Prerequisite is newer than target
248# (4) The command line stored in the file named dir/.target.cmd
249# differed from actual command line. This happens when compiler
250# options changes
251# (5) No dir/.target.cmd file (used to store command line)
252# (6) No dir/.target.cmd file and target not listed in $(targets)
253# This is a good hint that there is a bug in the kbuild file
254ifeq ($(KBUILD_VERBOSE),2)
255why = \
256 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
257 $(if $(wildcard $@), \
258 $(if $(newer-prereqs),- due to: $(newer-prereqs), \
259 $(if $(cmd-check), \
260 $(if $(cmd_$@),- due to command line change, \
261 $(if $(filter $@, $(targets)), \
262 - due to missing .cmd file, \
263 - due to $(notdir $@) not in $$(targets) \
264 ) \
265 ) \
266 ) \
267 ), \
268 - due to target missing \
269 ) \
270 )
271
272echo-why = $(call escsq, $(strip $(why)))
273endif
274
275###############################################################################
276#
277# When a Kconfig string contains a filename, it is suitable for
278# passing to shell commands. It is surrounded by double-quotes, and
279# any double-quotes or backslashes within it are escaped by
280# backslashes.
281#
282# This is no use for dependencies or $(wildcard). We need to strip the
283# surrounding quotes and the escaping from quotes and backslashes, and
284# we *do* need to escape any spaces in the string. So, for example:
285#
286# Usage: $(eval $(call config_filename,FOO))
287#
288# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
289# transformed as described above to be suitable for use within the
290# makefile.
291#
292# Also, if the filename is a relative filename and exists in the source
293# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
294# be prefixed to *both* command invocation and dependencies.
295#
296# Note: We also print the filenames in the quiet_cmd_foo text, and
297# perhaps ought to have a version specially escaped for that purpose.
298# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
299# enough. It'll strip the quotes in the common case where there's no
300# space and it's a simple filename, and it'll retain the quotes when
301# there's a space. There are some esoteric cases in which it'll print
302# the wrong thing, but we don't really care. The actual dependencies
303# and commands *do* get it right, with various combinations of single
304# and double quotes, backslashes and spaces in the filenames.
305#
306###############################################################################
307#
308define config_filename
309ifneq ($$(CONFIG_$(1)),"")
310$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
311ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
312else
313ifeq ($$(wildcard $$($(1)_FILENAME)),)
314ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
315$(1)_SRCPREFIX := $(srctree)/
316endif
317endif
318endif
319endif
320endef
321#
322###############################################################################
323
324# delete partially updated (i.e. corrupted) files on error
325.DELETE_ON_ERROR:
326
327# do not delete intermediate files automatically
328.SECONDARY: