Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1# ==========================================================================
2# Building
3# ==========================================================================
4
5src := $(obj)
6
7PHONY := __build
8__build:
9
10# Init all relevant variables used in kbuild files so
11# 1) they have correct type
12# 2) they do not inherit any value from the environment
13obj-y :=
14obj-m :=
15lib-y :=
16lib-m :=
17always :=
18targets :=
19subdir-y :=
20subdir-m :=
21EXTRA_AFLAGS :=
22EXTRA_CFLAGS :=
23EXTRA_CPPFLAGS :=
24EXTRA_LDFLAGS :=
25asflags-y :=
26ccflags-y :=
27cppflags-y :=
28ldflags-y :=
29
30subdir-asflags-y :=
31subdir-ccflags-y :=
32
33# Read auto.conf if it exists, otherwise ignore
34-include include/config/auto.conf
35
36include scripts/Kbuild.include
37
38# For backward compatibility check that these variables do not change
39save-cflags := $(CFLAGS)
40
41# The filename Kbuild has precedence over Makefile
42kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
43kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
44include $(kbuild-file)
45
46# If the save-* variables changed error out
47ifeq ($(KBUILD_NOPEDANTIC),)
48 ifneq ("$(save-cflags)","$(CFLAGS)")
49 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
50 endif
51endif
52
53include scripts/Makefile.lib
54
55ifdef host-progs
56ifneq ($(hostprogs-y),$(host-progs))
57$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
58hostprogs-y += $(host-progs)
59endif
60endif
61
62# Do not include host rules unless needed
63ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
64include scripts/Makefile.host
65endif
66
67ifneq ($(KBUILD_SRC),)
68# Create output directory if not already present
69_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
70
71# Create directories for object files if directory does not exist
72# Needed when obj-y := dir/file.o syntax is used
73_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
74endif
75
76ifndef obj
77$(warning kbuild: Makefile.build is included improperly)
78endif
79
80# ===========================================================================
81
82ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
83lib-target := $(obj)/lib.a
84obj-y += $(obj)/lib-ksyms.o
85endif
86
87ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
88builtin-target := $(obj)/built-in.o
89endif
90
91modorder-target := $(obj)/modules.order
92
93# We keep a list of all modules in $(MODVERDIR)
94
95__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
96 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
97 $(subdir-ym) $(always)
98 @:
99
100# Linus' kernel sanity checking tool
101ifneq ($(KBUILD_CHECKSRC),0)
102 ifeq ($(KBUILD_CHECKSRC),2)
103 quiet_cmd_force_checksrc = CHECK $<
104 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
105 else
106 quiet_cmd_checksrc = CHECK $<
107 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
108 endif
109endif
110
111# Do section mismatch analysis for each module/built-in.o
112ifdef CONFIG_DEBUG_SECTION_MISMATCH
113 cmd_secanalysis = ; scripts/mod/modpost $@
114endif
115
116# Compile C sources (.c)
117# ---------------------------------------------------------------------------
118
119# Default is built-in, unless we know otherwise
120modkern_cflags = \
121 $(if $(part-of-module), \
122 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
123 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
124quiet_modtag := $(empty) $(empty)
125
126$(real-objs-m) : part-of-module := y
127$(real-objs-m:.o=.i) : part-of-module := y
128$(real-objs-m:.o=.s) : part-of-module := y
129$(real-objs-m:.o=.lst): part-of-module := y
130
131$(real-objs-m) : quiet_modtag := [M]
132$(real-objs-m:.o=.i) : quiet_modtag := [M]
133$(real-objs-m:.o=.s) : quiet_modtag := [M]
134$(real-objs-m:.o=.lst): quiet_modtag := [M]
135
136$(obj-m) : quiet_modtag := [M]
137
138# Default for not multi-part modules
139modname = $(basetarget)
140
141$(multi-objs-m) : modname = $(modname-multi)
142$(multi-objs-m:.o=.i) : modname = $(modname-multi)
143$(multi-objs-m:.o=.s) : modname = $(modname-multi)
144$(multi-objs-m:.o=.lst) : modname = $(modname-multi)
145$(multi-objs-y) : modname = $(modname-multi)
146$(multi-objs-y:.o=.i) : modname = $(modname-multi)
147$(multi-objs-y:.o=.s) : modname = $(modname-multi)
148$(multi-objs-y:.o=.lst) : modname = $(modname-multi)
149
150quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
151cmd_cc_s_c = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
152
153$(obj)/%.s: $(src)/%.c FORCE
154 $(call if_changed_dep,cc_s_c)
155
156quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
157cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
158
159$(obj)/%.i: $(src)/%.c FORCE
160 $(call if_changed_dep,cpp_i_c)
161
162cmd_gensymtypes = \
163 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
164 $(GENKSYMS) $(if $(1), -T $(2)) \
165 $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
166 $(if $(KBUILD_PRESERVE),-p) \
167 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
168
169quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
170cmd_cc_symtypes_c = \
171 set -e; \
172 $(call cmd_gensymtypes,true,$@) >/dev/null; \
173 test -s $@ || rm -f $@
174
175$(obj)/%.symtypes : $(src)/%.c FORCE
176 $(call cmd,cc_symtypes_c)
177
178# C (.c) files
179# The C file is compiled and updated dependency information is generated.
180# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
181
182quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
183
184ifndef CONFIG_MODVERSIONS
185cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
186
187else
188# When module versioning is enabled the following steps are executed:
189# o compile a .tmp_<file>.o from <file>.c
190# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
191# not export symbols, we just rename .tmp_<file>.o to <file>.o and
192# are done.
193# o otherwise, we calculate symbol versions using the good old
194# genksyms on the preprocessed source and postprocess them in a way
195# that they are usable as a linker script
196# o generate <file>.o from .tmp_<file>.o using the linker to
197# replace the unresolved symbols __crc_exported_symbol with
198# the actual value of the checksum generated by genksyms
199
200cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
201cmd_modversions = \
202 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
203 $(call cmd_gensymtypes,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
204 > $(@D)/.tmp_$(@F:.o=.ver); \
205 \
206 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
207 -T $(@D)/.tmp_$(@F:.o=.ver); \
208 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
209 else \
210 mv -f $(@D)/.tmp_$(@F) $@; \
211 fi;
212endif
213
214ifdef CONFIG_FTRACE_MCOUNT_RECORD
215ifdef BUILD_C_RECORDMCOUNT
216ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
217 RECORDMCOUNT_FLAGS = -w
218endif
219# Due to recursion, we must skip empty.o.
220# The empty.o file is created in the make process in order to determine
221# the target endianness and word size. It is made before all other C
222# files, including recordmcount.
223sub_cmd_record_mcount = \
224 if [ $(@) != "scripts/mod/empty.o" ]; then \
225 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
226 fi;
227recordmcount_source := $(srctree)/scripts/recordmcount.c \
228 $(srctree)/scripts/recordmcount.h
229else
230sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
231 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
232 "$(if $(CONFIG_64BIT),64,32)" \
233 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
234 "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
235 "$(if $(part-of-module),1,0)" "$(@)";
236recordmcount_source := $(srctree)/scripts/recordmcount.pl
237endif
238cmd_record_mcount = \
239 if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" = \
240 "$(CC_FLAGS_FTRACE)" ]; then \
241 $(sub_cmd_record_mcount) \
242 fi;
243endif
244
245ifdef CONFIG_STACK_VALIDATION
246ifneq ($(SKIP_STACK_VALIDATION),1)
247
248__objtool_obj := $(objtree)/tools/objtool/objtool
249
250objtool_args = check
251ifndef CONFIG_FRAME_POINTER
252objtool_args += --no-fp
253endif
254
255# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
256# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
257# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
258cmd_objtool = $(if $(patsubst y%,, \
259 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
260 $(__objtool_obj) $(objtool_args) "$(@)";)
261objtool_obj = $(if $(patsubst y%,, \
262 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
263 $(__objtool_obj))
264
265endif # SKIP_STACK_VALIDATION
266endif # CONFIG_STACK_VALIDATION
267
268define rule_cc_o_c
269 $(call echo-cmd,checksrc) $(cmd_checksrc) \
270 $(call cmd_and_fixdep,cc_o_c) \
271 $(cmd_modversions) \
272 $(cmd_objtool) \
273 $(call echo-cmd,record_mcount) $(cmd_record_mcount)
274endef
275
276define rule_as_o_S
277 $(call cmd_and_fixdep,as_o_S) \
278 $(cmd_objtool)
279endef
280
281# List module undefined symbols (or empty line if not enabled)
282ifdef CONFIG_TRIM_UNUSED_KSYMS
283cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
284else
285cmd_undef_syms = echo
286endif
287
288# Built-in and composite module parts
289$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE
290 $(call cmd,force_checksrc)
291 $(call if_changed_rule,cc_o_c)
292
293# Single-part modules are special since we need to mark them in $(MODVERDIR)
294
295$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE
296 $(call cmd,force_checksrc)
297 $(call if_changed_rule,cc_o_c)
298 @{ echo $(@:.o=.ko); echo $@; \
299 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
300
301quiet_cmd_cc_lst_c = MKLST $@
302 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
303 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
304 System.map $(OBJDUMP) > $@
305
306$(obj)/%.lst: $(src)/%.c FORCE
307 $(call if_changed_dep,cc_lst_c)
308
309# Compile assembler sources (.S)
310# ---------------------------------------------------------------------------
311
312modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
313
314$(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
315$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
316
317quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
318cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
319
320$(obj)/%.s: $(src)/%.S FORCE
321 $(call if_changed_dep,cpp_s_S)
322
323quiet_cmd_as_o_S = AS $(quiet_modtag) $@
324cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
325
326$(obj)/%.o: $(src)/%.S $(objtool_obj) FORCE
327 $(call if_changed_rule,as_o_S)
328
329targets += $(real-objs-y) $(real-objs-m) $(lib-y)
330targets += $(extra-y) $(MAKECMDGOALS) $(always)
331
332# Linker scripts preprocessor (.lds.S -> .lds)
333# ---------------------------------------------------------------------------
334quiet_cmd_cpp_lds_S = LDS $@
335 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
336 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
337
338$(obj)/%.lds: $(src)/%.lds.S FORCE
339 $(call if_changed_dep,cpp_lds_S)
340
341# ASN.1 grammar
342# ---------------------------------------------------------------------------
343quiet_cmd_asn1_compiler = ASN.1 $@
344 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
345 $(subst .h,.c,$@) $(subst .c,.h,$@)
346
347.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
348
349$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
350 $(call cmd,asn1_compiler)
351
352# Build the compiled-in targets
353# ---------------------------------------------------------------------------
354
355# To build objects in subdirs, we need to descend into the directories
356$(sort $(subdir-obj-y)): $(subdir-ym) ;
357
358#
359# Rule to compile a set of .o files into one .o file
360#
361ifdef builtin-target
362
363ifdef CONFIG_THIN_ARCHIVES
364 cmd_make_builtin = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS)
365 cmd_make_empty_builtin = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS)
366 quiet_cmd_link_o_target = AR $@
367else
368 cmd_make_builtin = $(LD) $(ld_flags) -r -o
369 cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
370 quiet_cmd_link_o_target = LD $@
371endif
372
373# If the list of objects to link is empty, just create an empty built-in.o
374cmd_link_o_target = $(if $(strip $(obj-y)),\
375 $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
376 $(cmd_secanalysis),\
377 $(cmd_make_empty_builtin) $@)
378
379$(builtin-target): $(obj-y) FORCE
380 $(call if_changed,link_o_target)
381
382targets += $(builtin-target)
383endif # builtin-target
384
385#
386# Rule to create modules.order file
387#
388# Create commands to either record .ko file or cat modules.order from
389# a subdirectory
390modorder-cmds = \
391 $(foreach m, $(modorder), \
392 $(if $(filter %/modules.order, $m), \
393 cat $m;, echo kernel/$m;))
394
395$(modorder-target): $(subdir-ym) FORCE
396 $(Q)(cat /dev/null; $(modorder-cmds)) > $@
397
398#
399# Rule to compile a set of .o files into one .a file
400#
401ifdef lib-target
402quiet_cmd_link_l_target = AR $@
403
404ifdef CONFIG_THIN_ARCHIVES
405 cmd_link_l_target = rm -f $@; $(AR) rcsT$(KBUILD_ARFLAGS) $@ $(lib-y)
406else
407 cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
408endif
409
410$(lib-target): $(lib-y) FORCE
411 $(call if_changed,link_l_target)
412
413targets += $(lib-target)
414
415dummy-object = $(obj)/.lib_exports.o
416ksyms-lds = $(dot-target).lds
417ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
418ref_prefix = EXTERN(_
419else
420ref_prefix = EXTERN(
421endif
422
423quiet_cmd_export_list = EXPORTS $@
424cmd_export_list = $(OBJDUMP) -h $< | \
425 sed -ne '/___ksymtab/{s/.*+/$(ref_prefix)/;s/ .*/)/;p}' >$(ksyms-lds);\
426 rm -f $(dummy-object);\
427 $(AR) rcs$(KBUILD_ARFLAGS) $(dummy-object);\
428 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
429 rm $(dummy-object) $(ksyms-lds)
430
431$(obj)/lib-ksyms.o: $(lib-target) FORCE
432 $(call if_changed,export_list)
433endif
434
435#
436# Rule to link composite objects
437#
438# Composite objects are specified in kbuild makefile as follows:
439# <composite-object>-objs := <list of .o files>
440# or
441# <composite-object>-y := <list of .o files>
442# or
443# <composite-object>-m := <list of .o files>
444# The -m syntax only works if <composite object> is a module
445link_multi_deps = \
446$(filter $(addprefix $(obj)/, \
447$($(subst $(obj)/,,$(@:.o=-objs))) \
448$($(subst $(obj)/,,$(@:.o=-y))) \
449$($(subst $(obj)/,,$(@:.o=-m)))), $^)
450
451quiet_cmd_link_multi-y = LD $@
452cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
453
454quiet_cmd_link_multi-m = LD [M] $@
455cmd_link_multi-m = $(cmd_link_multi-y)
456
457$(multi-used-y): FORCE
458 $(call if_changed,link_multi-y)
459$(call multi_depend, $(multi-used-y), .o, -objs -y)
460
461$(multi-used-m): FORCE
462 $(call if_changed,link_multi-m)
463 @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
464 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
465$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
466
467targets += $(multi-used-y) $(multi-used-m)
468
469
470# Descending
471# ---------------------------------------------------------------------------
472
473PHONY += $(subdir-ym)
474$(subdir-ym):
475 $(Q)$(MAKE) $(build)=$@
476
477# Add FORCE to the prequisites of a target to force it to be always rebuilt.
478# ---------------------------------------------------------------------------
479
480PHONY += FORCE
481
482FORCE:
483
484# Read all saved command lines and dependencies for the $(targets) we
485# may be building above, using $(if_changed{,_dep}). As an
486# optimization, we don't need to read them if the target does not
487# exist, we will rebuild anyway in that case.
488
489targets := $(wildcard $(sort $(targets)))
490cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
491
492ifneq ($(cmd_files),)
493 include $(cmd_files)
494endif
495
496# Declare the contents of the .PHONY variable as phony. We keep that
497# information in a variable se we can use it in if_changed and friends.
498
499.PHONY: $(PHONY)