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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
162# These mirror gensymtypes_S and co below, keep them in synch.
163cmd_gensymtypes_c = \
164 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
165 $(GENKSYMS) $(if $(1), -T $(2)) \
166 $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
167 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
168 $(if $(KBUILD_PRESERVE),-p) \
169 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
170
171quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
172cmd_cc_symtypes_c = \
173 set -e; \
174 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \
175 test -s $@ || rm -f $@
176
177$(obj)/%.symtypes : $(src)/%.c FORCE
178 $(call cmd,cc_symtypes_c)
179
180# C (.c) files
181# The C file is compiled and updated dependency information is generated.
182# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
183
184quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
185
186ifndef CONFIG_MODVERSIONS
187cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
188
189else
190# When module versioning is enabled the following steps are executed:
191# o compile a .tmp_<file>.o from <file>.c
192# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
193# not export symbols, we just rename .tmp_<file>.o to <file>.o and
194# are done.
195# o otherwise, we calculate symbol versions using the good old
196# genksyms on the preprocessed source and postprocess them in a way
197# that they are usable as a linker script
198# o generate <file>.o from .tmp_<file>.o using the linker to
199# replace the unresolved symbols __crc_exported_symbol with
200# the actual value of the checksum generated by genksyms
201
202cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
203
204cmd_modversions_c = \
205 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
206 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
207 > $(@D)/.tmp_$(@F:.o=.ver); \
208 \
209 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
210 -T $(@D)/.tmp_$(@F:.o=.ver); \
211 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
212 else \
213 mv -f $(@D)/.tmp_$(@F) $@; \
214 fi;
215endif
216
217ifdef CONFIG_FTRACE_MCOUNT_RECORD
218ifdef BUILD_C_RECORDMCOUNT
219ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
220 RECORDMCOUNT_FLAGS = -w
221endif
222# Due to recursion, we must skip empty.o.
223# The empty.o file is created in the make process in order to determine
224# the target endianness and word size. It is made before all other C
225# files, including recordmcount.
226sub_cmd_record_mcount = \
227 if [ $(@) != "scripts/mod/empty.o" ]; then \
228 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
229 fi;
230recordmcount_source := $(srctree)/scripts/recordmcount.c \
231 $(srctree)/scripts/recordmcount.h
232else
233sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
234 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
235 "$(if $(CONFIG_64BIT),64,32)" \
236 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
237 "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
238 "$(if $(part-of-module),1,0)" "$(@)";
239recordmcount_source := $(srctree)/scripts/recordmcount.pl
240endif
241cmd_record_mcount = \
242 if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" = \
243 "$(CC_FLAGS_FTRACE)" ]; then \
244 $(sub_cmd_record_mcount) \
245 fi;
246endif
247
248ifdef CONFIG_STACK_VALIDATION
249ifneq ($(SKIP_STACK_VALIDATION),1)
250
251__objtool_obj := $(objtree)/tools/objtool/objtool
252
253objtool_args = check
254ifndef CONFIG_FRAME_POINTER
255objtool_args += --no-fp
256endif
257
258# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
259# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
260# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
261cmd_objtool = $(if $(patsubst y%,, \
262 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
263 $(__objtool_obj) $(objtool_args) "$(@)";)
264objtool_obj = $(if $(patsubst y%,, \
265 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
266 $(__objtool_obj))
267
268endif # SKIP_STACK_VALIDATION
269endif # CONFIG_STACK_VALIDATION
270
271define rule_cc_o_c
272 $(call echo-cmd,checksrc) $(cmd_checksrc) \
273 $(call cmd_and_fixdep,cc_o_c) \
274 $(cmd_modversions_c) \
275 $(cmd_objtool) \
276 $(call echo-cmd,record_mcount) $(cmd_record_mcount)
277endef
278
279define rule_as_o_S
280 $(call cmd_and_fixdep,as_o_S) \
281 $(cmd_modversions_S) \
282 $(cmd_objtool)
283endef
284
285# List module undefined symbols (or empty line if not enabled)
286ifdef CONFIG_TRIM_UNUSED_KSYMS
287cmd_undef_syms = $(NM) $@ | sed -n 's/^ \+U //p' | xargs echo
288else
289cmd_undef_syms = echo
290endif
291
292# Built-in and composite module parts
293$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE
294 $(call cmd,force_checksrc)
295 $(call if_changed_rule,cc_o_c)
296
297# Single-part modules are special since we need to mark them in $(MODVERDIR)
298
299$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_obj) FORCE
300 $(call cmd,force_checksrc)
301 $(call if_changed_rule,cc_o_c)
302 @{ echo $(@:.o=.ko); echo $@; \
303 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
304
305quiet_cmd_cc_lst_c = MKLST $@
306 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
307 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
308 System.map $(OBJDUMP) > $@
309
310$(obj)/%.lst: $(src)/%.c FORCE
311 $(call if_changed_dep,cc_lst_c)
312
313# Compile assembler sources (.S)
314# ---------------------------------------------------------------------------
315
316modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
317
318$(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
319$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
320
321# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
322# or a file that it includes, in order to get versioned symbols. We build a
323# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
324# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
325#
326# This is convoluted. The .S file must first be preprocessed to run guards and
327# expand names, then the resulting exports must be constructed into plain
328# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
329# to make the genksyms input.
330#
331# These mirror gensymtypes_c and co above, keep them in synch.
332cmd_gensymtypes_S = \
333 (echo "\#include <linux/kernel.h>" ; \
334 echo "\#include <asm/asm-prototypes.h>" ; \
335 $(CPP) $(a_flags) $< | \
336 grep "\<___EXPORT_SYMBOL\>" | \
337 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
338 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
339 $(GENKSYMS) $(if $(1), -T $(2)) \
340 $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
341 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
342 $(if $(KBUILD_PRESERVE),-p) \
343 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
344
345quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
346cmd_cc_symtypes_S = \
347 set -e; \
348 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
349 test -s $@ || rm -f $@
350
351$(obj)/%.symtypes : $(src)/%.S FORCE
352 $(call cmd,cc_symtypes_S)
353
354
355quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
356cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
357
358$(obj)/%.s: $(src)/%.S FORCE
359 $(call if_changed_dep,cpp_s_S)
360
361quiet_cmd_as_o_S = AS $(quiet_modtag) $@
362
363ifndef CONFIG_MODVERSIONS
364cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
365
366else
367
368ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
369
370ifeq ($(ASM_PROTOTYPES),)
371cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
372
373else
374
375# versioning matches the C process described above, with difference that
376# we parse asm-prototypes.h C header to get function definitions.
377
378cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
379
380cmd_modversions_S = \
381 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
382 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
383 > $(@D)/.tmp_$(@F:.o=.ver); \
384 \
385 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
386 -T $(@D)/.tmp_$(@F:.o=.ver); \
387 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
388 else \
389 mv -f $(@D)/.tmp_$(@F) $@; \
390 fi;
391endif
392endif
393
394$(obj)/%.o: $(src)/%.S $(objtool_obj) FORCE
395 $(call if_changed_rule,as_o_S)
396
397targets += $(real-objs-y) $(real-objs-m) $(lib-y)
398targets += $(extra-y) $(MAKECMDGOALS) $(always)
399
400# Linker scripts preprocessor (.lds.S -> .lds)
401# ---------------------------------------------------------------------------
402quiet_cmd_cpp_lds_S = LDS $@
403 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
404 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
405
406$(obj)/%.lds: $(src)/%.lds.S FORCE
407 $(call if_changed_dep,cpp_lds_S)
408
409# ASN.1 grammar
410# ---------------------------------------------------------------------------
411quiet_cmd_asn1_compiler = ASN.1 $@
412 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
413 $(subst .h,.c,$@) $(subst .c,.h,$@)
414
415.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
416
417$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
418 $(call cmd,asn1_compiler)
419
420# Build the compiled-in targets
421# ---------------------------------------------------------------------------
422
423# To build objects in subdirs, we need to descend into the directories
424$(sort $(subdir-obj-y)): $(subdir-ym) ;
425
426#
427# Rule to compile a set of .o files into one .o file
428#
429ifdef builtin-target
430
431ifdef CONFIG_THIN_ARCHIVES
432 cmd_make_builtin = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS)
433 cmd_make_empty_builtin = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS)
434 quiet_cmd_link_o_target = AR $@
435else
436 cmd_make_builtin = $(LD) $(ld_flags) -r -o
437 cmd_make_empty_builtin = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS)
438 quiet_cmd_link_o_target = LD $@
439endif
440
441# If the list of objects to link is empty, just create an empty built-in.o
442cmd_link_o_target = $(if $(strip $(obj-y)),\
443 $(cmd_make_builtin) $@ $(filter $(obj-y), $^) \
444 $(cmd_secanalysis),\
445 $(cmd_make_empty_builtin) $@)
446
447$(builtin-target): $(obj-y) FORCE
448 $(call if_changed,link_o_target)
449
450targets += $(builtin-target)
451endif # builtin-target
452
453#
454# Rule to create modules.order file
455#
456# Create commands to either record .ko file or cat modules.order from
457# a subdirectory
458modorder-cmds = \
459 $(foreach m, $(modorder), \
460 $(if $(filter %/modules.order, $m), \
461 cat $m;, echo kernel/$m;))
462
463$(modorder-target): $(subdir-ym) FORCE
464 $(Q)(cat /dev/null; $(modorder-cmds)) > $@
465
466#
467# Rule to compile a set of .o files into one .a file
468#
469ifdef lib-target
470quiet_cmd_link_l_target = AR $@
471
472ifdef CONFIG_THIN_ARCHIVES
473 cmd_link_l_target = rm -f $@; $(AR) rcsT$(KBUILD_ARFLAGS) $@ $(lib-y)
474else
475 cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
476endif
477
478$(lib-target): $(lib-y) FORCE
479 $(call if_changed,link_l_target)
480
481targets += $(lib-target)
482
483dummy-object = $(obj)/.lib_exports.o
484ksyms-lds = $(dot-target).lds
485ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
486ref_prefix = EXTERN(_
487else
488ref_prefix = EXTERN(
489endif
490
491quiet_cmd_export_list = EXPORTS $@
492cmd_export_list = $(OBJDUMP) -h $< | \
493 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
494 rm -f $(dummy-object);\
495 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
496 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
497 rm $(dummy-object) $(ksyms-lds)
498
499$(obj)/lib-ksyms.o: $(lib-target) FORCE
500 $(call if_changed,export_list)
501
502targets += $(obj)/lib-ksyms.o
503
504endif
505
506#
507# Rule to link composite objects
508#
509# Composite objects are specified in kbuild makefile as follows:
510# <composite-object>-objs := <list of .o files>
511# or
512# <composite-object>-y := <list of .o files>
513# or
514# <composite-object>-m := <list of .o files>
515# The -m syntax only works if <composite object> is a module
516link_multi_deps = \
517$(filter $(addprefix $(obj)/, \
518$($(subst $(obj)/,,$(@:.o=-objs))) \
519$($(subst $(obj)/,,$(@:.o=-y))) \
520$($(subst $(obj)/,,$(@:.o=-m)))), $^)
521
522cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
523
524ifdef CONFIG_THIN_ARCHIVES
525 quiet_cmd_link_multi-y = AR $@
526 cmd_link_multi-y = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
527else
528 quiet_cmd_link_multi-y = LD $@
529 cmd_link_multi-y = $(cmd_link_multi-link)
530endif
531
532quiet_cmd_link_multi-m = LD [M] $@
533cmd_link_multi-m = $(cmd_link_multi-link)
534
535$(multi-used-y): FORCE
536 $(call if_changed,link_multi-y)
537$(call multi_depend, $(multi-used-y), .o, -objs -y)
538
539$(multi-used-m): FORCE
540 $(call if_changed,link_multi-m)
541 @{ echo $(@:.o=.ko); echo $(link_multi_deps); \
542 $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
543$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
544
545targets += $(multi-used-y) $(multi-used-m)
546
547
548# Descending
549# ---------------------------------------------------------------------------
550
551PHONY += $(subdir-ym)
552$(subdir-ym):
553 $(Q)$(MAKE) $(build)=$@
554
555# Add FORCE to the prequisites of a target to force it to be always rebuilt.
556# ---------------------------------------------------------------------------
557
558PHONY += FORCE
559
560FORCE:
561
562# Read all saved command lines and dependencies for the $(targets) we
563# may be building above, using $(if_changed{,_dep}). As an
564# optimization, we don't need to read them if the target does not
565# exist, we will rebuild anyway in that case.
566
567targets := $(wildcard $(sort $(targets)))
568cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
569
570ifneq ($(cmd_files),)
571 include $(cmd_files)
572endif
573
574# Declare the contents of the .PHONY variable as phony. We keep that
575# information in a variable se we can use it in if_changed and friends.
576
577.PHONY: $(PHONY)
1# SPDX-License-Identifier: GPL-2.0
2# ==========================================================================
3# Building
4# ==========================================================================
5
6src := $(obj)
7
8PHONY := __build
9__build:
10
11# Init all relevant variables used in kbuild files so
12# 1) they have correct type
13# 2) they do not inherit any value from the environment
14obj-y :=
15obj-m :=
16lib-y :=
17lib-m :=
18always :=
19always-y :=
20always-m :=
21targets :=
22subdir-y :=
23subdir-m :=
24EXTRA_AFLAGS :=
25EXTRA_CFLAGS :=
26EXTRA_CPPFLAGS :=
27EXTRA_LDFLAGS :=
28asflags-y :=
29ccflags-y :=
30cppflags-y :=
31ldflags-y :=
32
33subdir-asflags-y :=
34subdir-ccflags-y :=
35
36# Read auto.conf if it exists, otherwise ignore
37-include include/config/auto.conf
38
39include scripts/Kbuild.include
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
46include scripts/Makefile.lib
47
48# Do not include hostprogs rules unless needed.
49# $(sort ...) is used here to remove duplicated words and excessive spaces.
50hostprogs := $(sort $(hostprogs))
51ifneq ($(hostprogs),)
52include scripts/Makefile.host
53endif
54
55# Do not include userprogs rules unless needed.
56# $(sort ...) is used here to remove duplicated words and excessive spaces.
57userprogs := $(sort $(userprogs))
58ifneq ($(userprogs),)
59include scripts/Makefile.userprogs
60endif
61
62ifndef obj
63$(warning kbuild: Makefile.build is included improperly)
64endif
65
66ifeq ($(need-modorder),)
67ifneq ($(obj-m),)
68$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
69$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
70endif
71endif
72
73# ===========================================================================
74
75# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...)
76subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y)))
77subdir-modorder := $(sort $(filter %/modules.order, $(obj-m)))
78
79targets-for-builtin := $(extra-y)
80
81ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
82targets-for-builtin += $(obj)/lib.a
83endif
84
85ifdef need-builtin
86targets-for-builtin += $(obj)/built-in.a
87endif
88
89targets-for-modules := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m)))
90
91ifdef need-modorder
92targets-for-modules += $(obj)/modules.order
93endif
94
95targets += $(targets-for-builtin) $(targets-for-modules)
96
97# Linus' kernel sanity checking tool
98ifeq ($(KBUILD_CHECKSRC),1)
99 quiet_cmd_checksrc = CHECK $<
100 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
101else ifeq ($(KBUILD_CHECKSRC),2)
102 quiet_cmd_force_checksrc = CHECK $<
103 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
104endif
105
106ifneq ($(KBUILD_EXTRA_WARN),)
107 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
108endif
109
110# Compile C sources (.c)
111# ---------------------------------------------------------------------------
112
113quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
114 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
115
116$(obj)/%.s: $(src)/%.c FORCE
117 $(call if_changed_dep,cc_s_c)
118
119quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
120cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
121
122$(obj)/%.i: $(src)/%.c FORCE
123 $(call if_changed_dep,cpp_i_c)
124
125# These mirror gensymtypes_S and co below, keep them in synch.
126cmd_gensymtypes_c = \
127 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
128 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
129 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
130 $(if $(KBUILD_PRESERVE),-p) \
131 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
132
133quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
134cmd_cc_symtypes_c = \
135 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \
136 test -s $@ || rm -f $@
137
138$(obj)/%.symtypes : $(src)/%.c FORCE
139 $(call cmd,cc_symtypes_c)
140
141# LLVM assembly
142# Generate .ll files from .c
143quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
144 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
145
146$(obj)/%.ll: $(src)/%.c FORCE
147 $(call if_changed_dep,cc_ll_c)
148
149# C (.c) files
150# The C file is compiled and updated dependency information is generated.
151# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
152
153quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
154 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
155
156ifdef CONFIG_MODVERSIONS
157# When module versioning is enabled the following steps are executed:
158# o compile a <file>.o from <file>.c
159# o if <file>.o doesn't contain a __ksymtab version, i.e. does
160# not export symbols, it's done.
161# o otherwise, we calculate symbol versions using the good old
162# genksyms on the preprocessed source and postprocess them in a way
163# that they are usable as a linker script
164# o generate .tmp_<file>.o from <file>.o using the linker to
165# replace the unresolved symbols __crc_exported_symbol with
166# the actual value of the checksum generated by genksyms
167# o remove .tmp_<file>.o to <file>.o
168
169cmd_modversions_c = \
170 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
171 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
172 > $(@D)/.tmp_$(@F:.o=.ver); \
173 \
174 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
175 -T $(@D)/.tmp_$(@F:.o=.ver); \
176 mv -f $(@D)/.tmp_$(@F) $@; \
177 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
178 fi
179endif
180
181ifdef CONFIG_FTRACE_MCOUNT_RECORD
182ifndef CC_USING_RECORD_MCOUNT
183# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
184ifdef BUILD_C_RECORDMCOUNT
185ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
186 RECORDMCOUNT_FLAGS = -w
187endif
188# Due to recursion, we must skip empty.o.
189# The empty.o file is created in the make process in order to determine
190# the target endianness and word size. It is made before all other C
191# files, including recordmcount.
192sub_cmd_record_mcount = \
193 if [ $(@) != "scripts/mod/empty.o" ]; then \
194 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
195 fi;
196recordmcount_source := $(srctree)/scripts/recordmcount.c \
197 $(srctree)/scripts/recordmcount.h
198else
199sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
200 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
201 "$(if $(CONFIG_64BIT),64,32)" \
202 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
203 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
204 "$(if $(part-of-module),1,0)" "$(@)";
205recordmcount_source := $(srctree)/scripts/recordmcount.pl
206endif # BUILD_C_RECORDMCOUNT
207cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
208 $(sub_cmd_record_mcount))
209endif # CC_USING_RECORD_MCOUNT
210endif # CONFIG_FTRACE_MCOUNT_RECORD
211
212ifdef CONFIG_STACK_VALIDATION
213ifneq ($(SKIP_STACK_VALIDATION),1)
214
215__objtool_obj := $(objtree)/tools/objtool/objtool
216
217objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
218
219objtool_args += $(if $(part-of-module), --module,)
220
221ifndef CONFIG_FRAME_POINTER
222objtool_args += --no-fp
223endif
224ifdef CONFIG_GCOV_KERNEL
225objtool_args += --no-unreachable
226endif
227ifdef CONFIG_RETPOLINE
228 objtool_args += --retpoline
229endif
230ifdef CONFIG_X86_SMAP
231 objtool_args += --uaccess
232endif
233
234# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
235# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
236# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
237cmd_objtool = $(if $(patsubst y%,, \
238 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
239 $(__objtool_obj) $(objtool_args) $@)
240objtool_obj = $(if $(patsubst y%,, \
241 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
242 $(__objtool_obj))
243
244endif # SKIP_STACK_VALIDATION
245endif # CONFIG_STACK_VALIDATION
246
247# Rebuild all objects when objtool changes, or is enabled/disabled.
248objtool_dep = $(objtool_obj) \
249 $(wildcard include/config/orc/unwinder.h \
250 include/config/stack/validation.h)
251
252ifdef CONFIG_TRIM_UNUSED_KSYMS
253cmd_gen_ksymdeps = \
254 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
255endif
256
257define rule_cc_o_c
258 $(call cmd_and_fixdep,cc_o_c)
259 $(call cmd,gen_ksymdeps)
260 $(call cmd,checksrc)
261 $(call cmd,checkdoc)
262 $(call cmd,objtool)
263 $(call cmd,modversions_c)
264 $(call cmd,record_mcount)
265endef
266
267define rule_as_o_S
268 $(call cmd_and_fixdep,as_o_S)
269 $(call cmd,gen_ksymdeps)
270 $(call cmd,objtool)
271 $(call cmd,modversions_S)
272endef
273
274# List module undefined symbols (or empty line if not enabled)
275ifdef CONFIG_TRIM_UNUSED_KSYMS
276cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo
277else
278cmd_undef_syms = echo
279endif
280
281# Built-in and composite module parts
282$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
283 $(call if_changed_rule,cc_o_c)
284 $(call cmd,force_checksrc)
285
286cmd_mod = { \
287 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
288 $(cmd_undef_syms); \
289 } > $@
290
291$(obj)/%.mod: $(obj)/%.o FORCE
292 $(call if_changed,mod)
293
294quiet_cmd_cc_lst_c = MKLST $@
295 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
296 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
297 System.map $(OBJDUMP) > $@
298
299$(obj)/%.lst: $(src)/%.c FORCE
300 $(call if_changed_dep,cc_lst_c)
301
302# Compile assembler sources (.S)
303# ---------------------------------------------------------------------------
304
305# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
306# or a file that it includes, in order to get versioned symbols. We build a
307# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
308# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
309#
310# This is convoluted. The .S file must first be preprocessed to run guards and
311# expand names, then the resulting exports must be constructed into plain
312# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
313# to make the genksyms input.
314#
315# These mirror gensymtypes_c and co above, keep them in synch.
316cmd_gensymtypes_S = \
317 { echo "\#include <linux/kernel.h>" ; \
318 echo "\#include <asm/asm-prototypes.h>" ; \
319 $(CPP) $(a_flags) $< | \
320 grep "\<___EXPORT_SYMBOL\>" | \
321 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
322 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
323 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
324 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
325 $(if $(KBUILD_PRESERVE),-p) \
326 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
327
328quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
329cmd_cc_symtypes_S = \
330 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
331 test -s $@ || rm -f $@
332
333$(obj)/%.symtypes : $(src)/%.S FORCE
334 $(call cmd,cc_symtypes_S)
335
336
337quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
338cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
339
340$(obj)/%.s: $(src)/%.S FORCE
341 $(call if_changed_dep,cpp_s_S)
342
343quiet_cmd_as_o_S = AS $(quiet_modtag) $@
344 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
345
346ifdef CONFIG_ASM_MODVERSIONS
347
348# versioning matches the C process described above, with difference that
349# we parse asm-prototypes.h C header to get function definitions.
350
351cmd_modversions_S = \
352 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
353 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
354 > $(@D)/.tmp_$(@F:.o=.ver); \
355 \
356 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
357 -T $(@D)/.tmp_$(@F:.o=.ver); \
358 mv -f $(@D)/.tmp_$(@F) $@; \
359 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
360 fi
361endif
362
363$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
364 $(call if_changed_rule,as_o_S)
365
366targets += $(filter-out $(subdir-builtin), $(real-obj-y))
367targets += $(filter-out $(subdir-modorder), $(real-obj-m))
368targets += $(lib-y) $(always-y) $(MAKECMDGOALS)
369
370# Linker scripts preprocessor (.lds.S -> .lds)
371# ---------------------------------------------------------------------------
372quiet_cmd_cpp_lds_S = LDS $@
373 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
374 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
375
376$(obj)/%.lds: $(src)/%.lds.S FORCE
377 $(call if_changed_dep,cpp_lds_S)
378
379# ASN.1 grammar
380# ---------------------------------------------------------------------------
381quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch]
382 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
383 $(basename $@).c $(basename $@).h
384
385$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
386 $(call cmd,asn1_compiler)
387
388# Build the compiled-in targets
389# ---------------------------------------------------------------------------
390
391# To build objects in subdirs, we need to descend into the directories
392$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;
393$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
394
395#
396# Rule to compile a set of .o files into one .a file (without symbol table)
397#
398
399quiet_cmd_ar_builtin = AR $@
400 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs)
401
402$(obj)/built-in.a: $(real-obj-y) FORCE
403 $(call if_changed,ar_builtin)
404
405#
406# Rule to create modules.order file
407#
408# Create commands to either record .ko file or cat modules.order from
409# a subdirectory
410# Add $(obj-m) as the prerequisite to avoid updating the timestamp of
411# modules.order unless contained modules are updated.
412
413cmd_modules_order = { $(foreach m, $(real-prereqs), \
414 $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \
415 | $(AWK) '!x[$$0]++' - > $@
416
417$(obj)/modules.order: $(obj-m) FORCE
418 $(call if_changed,modules_order)
419
420#
421# Rule to compile a set of .o files into one .a file (with symbol table)
422#
423$(obj)/lib.a: $(lib-y) FORCE
424 $(call if_changed,ar)
425
426# NOTE:
427# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
428# module is turned into a multi object module, $^ will contain header file
429# dependencies recorded in the .*.cmd file.
430quiet_cmd_link_multi-m = LD [M] $@
431 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
432
433$(multi-used-m): FORCE
434 $(call if_changed,link_multi-m)
435$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
436
437targets += $(multi-used-m)
438targets := $(filter-out $(PHONY), $(targets))
439
440# Add intermediate targets:
441# When building objects with specific suffix patterns, add intermediate
442# targets that the final targets are derived from.
443intermediate_targets = $(foreach sfx, $(2), \
444 $(patsubst %$(strip $(1)),%$(sfx), \
445 $(filter %$(strip $(1)), $(targets))))
446# %.asn1.o <- %.asn1.[ch] <- %.asn1
447# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
448# %.lex.o <- %.lex.c <- %.l
449# %.tab.o <- %.tab.[ch] <- %.y
450targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
451 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
452 $(call intermediate_targets, .lex.o, .lex.c) \
453 $(call intermediate_targets, .tab.o, .tab.c .tab.h)
454
455# Build
456# ---------------------------------------------------------------------------
457
458ifdef single-build
459
460KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS))
461
462curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \
463 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x))))
464
465# Handle single targets without any rule: show "Nothing to be done for ..." or
466# "No rule to make target ..." depending on whether the target exists.
467unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \
468 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS)))
469
470single-subdirs := $(foreach d, $(subdir-ym), \
471 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d)))
472
473__build: $(curdir-single) $(single-subdirs)
474ifneq ($(unknown-single),)
475 $(Q)$(MAKE) -f /dev/null $(unknown-single)
476endif
477 @:
478
479ifeq ($(curdir-single),)
480# Nothing to do in this directory. Do not include any .*.cmd file for speed-up
481targets :=
482else
483targets += $(curdir-single)
484endif
485
486else
487
488__build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \
489 $(if $(KBUILD_MODULES), $(targets-for-modules)) \
490 $(subdir-ym) $(always-y)
491 @:
492
493endif
494
495# Descending
496# ---------------------------------------------------------------------------
497
498PHONY += $(subdir-ym)
499$(subdir-ym):
500 $(Q)$(MAKE) $(build)=$@ \
501 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
502 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \
503 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1)
504
505# Add FORCE to the prequisites of a target to force it to be always rebuilt.
506# ---------------------------------------------------------------------------
507
508PHONY += FORCE
509
510FORCE:
511
512# Read all saved command lines and dependencies for the $(targets) we
513# may be building above, using $(if_changed{,_dep}). As an
514# optimization, we don't need to read them if the target does not
515# exist, we will rebuild anyway in that case.
516
517existing-targets := $(wildcard $(sort $(targets)))
518
519-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
520
521# Create directories for object files if they do not exist
522obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets))))
523# If targets exist, their directories apparently exist. Skip mkdir.
524existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
525obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
526ifneq ($(obj-dirs),)
527$(shell mkdir -p $(obj-dirs))
528endif
529
530.PHONY: $(PHONY)