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# 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 $(kbuild-file)
45
46include scripts/Makefile.lib
47
48# Do not include host rules unless needed
49ifneq ($(hostprogs)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
50include scripts/Makefile.host
51endif
52
53ifndef obj
54$(warning kbuild: Makefile.build is included improperly)
55endif
56
57ifeq ($(need-modorder),)
58ifneq ($(obj-m),)
59$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
60$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
61endif
62endif
63
64# ===========================================================================
65
66ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
67lib-target := $(obj)/lib.a
68real-obj-y += $(obj)/lib-ksyms.o
69endif
70
71ifdef need-builtin
72builtin-target := $(obj)/built-in.a
73endif
74
75ifeq ($(CONFIG_MODULES)$(need-modorder),y1)
76modorder-target := $(obj)/modules.order
77endif
78
79mod-targets := $(patsubst %.o, %.mod, $(obj-m))
80
81# Linus' kernel sanity checking tool
82ifeq ($(KBUILD_CHECKSRC),1)
83 quiet_cmd_checksrc = CHECK $<
84 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
85else ifeq ($(KBUILD_CHECKSRC),2)
86 quiet_cmd_force_checksrc = CHECK $<
87 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
88endif
89
90ifneq ($(KBUILD_EXTRA_WARN),)
91 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
92endif
93
94# Compile C sources (.c)
95# ---------------------------------------------------------------------------
96
97quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
98 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
99
100$(obj)/%.s: $(src)/%.c FORCE
101 $(call if_changed_dep,cc_s_c)
102
103quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
104cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
105
106$(obj)/%.i: $(src)/%.c FORCE
107 $(call if_changed_dep,cpp_i_c)
108
109# These mirror gensymtypes_S and co below, keep them in synch.
110cmd_gensymtypes_c = \
111 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
112 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
113 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
114 $(if $(KBUILD_PRESERVE),-p) \
115 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
116
117quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
118cmd_cc_symtypes_c = \
119 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \
120 test -s $@ || rm -f $@
121
122$(obj)/%.symtypes : $(src)/%.c FORCE
123 $(call cmd,cc_symtypes_c)
124
125# LLVM assembly
126# Generate .ll files from .c
127quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
128 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
129
130$(obj)/%.ll: $(src)/%.c FORCE
131 $(call if_changed_dep,cc_ll_c)
132
133# C (.c) files
134# The C file is compiled and updated dependency information is generated.
135# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
136
137quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
138 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
139
140ifdef CONFIG_MODVERSIONS
141# When module versioning is enabled the following steps are executed:
142# o compile a <file>.o from <file>.c
143# o if <file>.o doesn't contain a __ksymtab version, i.e. does
144# not export symbols, it's done.
145# o otherwise, we calculate symbol versions using the good old
146# genksyms on the preprocessed source and postprocess them in a way
147# that they are usable as a linker script
148# o generate .tmp_<file>.o from <file>.o using the linker to
149# replace the unresolved symbols __crc_exported_symbol with
150# the actual value of the checksum generated by genksyms
151# o remove .tmp_<file>.o to <file>.o
152
153cmd_modversions_c = \
154 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
155 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
156 > $(@D)/.tmp_$(@F:.o=.ver); \
157 \
158 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
159 -T $(@D)/.tmp_$(@F:.o=.ver); \
160 mv -f $(@D)/.tmp_$(@F) $@; \
161 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
162 fi
163endif
164
165ifdef CONFIG_FTRACE_MCOUNT_RECORD
166ifndef CC_USING_RECORD_MCOUNT
167# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
168ifdef BUILD_C_RECORDMCOUNT
169ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
170 RECORDMCOUNT_FLAGS = -w
171endif
172# Due to recursion, we must skip empty.o.
173# The empty.o file is created in the make process in order to determine
174# the target endianness and word size. It is made before all other C
175# files, including recordmcount.
176sub_cmd_record_mcount = \
177 if [ $(@) != "scripts/mod/empty.o" ]; then \
178 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
179 fi;
180recordmcount_source := $(srctree)/scripts/recordmcount.c \
181 $(srctree)/scripts/recordmcount.h
182else
183sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
184 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
185 "$(if $(CONFIG_64BIT),64,32)" \
186 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
187 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
188 "$(if $(part-of-module),1,0)" "$(@)";
189recordmcount_source := $(srctree)/scripts/recordmcount.pl
190endif # BUILD_C_RECORDMCOUNT
191cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
192 $(sub_cmd_record_mcount))
193endif # CC_USING_RECORD_MCOUNT
194endif # CONFIG_FTRACE_MCOUNT_RECORD
195
196ifdef CONFIG_STACK_VALIDATION
197ifneq ($(SKIP_STACK_VALIDATION),1)
198
199__objtool_obj := $(objtree)/tools/objtool/objtool
200
201objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
202
203objtool_args += $(if $(part-of-module), --module,)
204
205ifndef CONFIG_FRAME_POINTER
206objtool_args += --no-fp
207endif
208ifdef CONFIG_GCOV_KERNEL
209objtool_args += --no-unreachable
210endif
211ifdef CONFIG_RETPOLINE
212 objtool_args += --retpoline
213endif
214ifdef CONFIG_X86_SMAP
215 objtool_args += --uaccess
216endif
217
218# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
219# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
220# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
221cmd_objtool = $(if $(patsubst y%,, \
222 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
223 $(__objtool_obj) $(objtool_args) $@)
224objtool_obj = $(if $(patsubst y%,, \
225 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
226 $(__objtool_obj))
227
228endif # SKIP_STACK_VALIDATION
229endif # CONFIG_STACK_VALIDATION
230
231# Rebuild all objects when objtool changes, or is enabled/disabled.
232objtool_dep = $(objtool_obj) \
233 $(wildcard include/config/orc/unwinder.h \
234 include/config/stack/validation.h)
235
236ifdef CONFIG_TRIM_UNUSED_KSYMS
237cmd_gen_ksymdeps = \
238 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
239endif
240
241define rule_cc_o_c
242 $(call cmd,checksrc)
243 $(call cmd_and_fixdep,cc_o_c)
244 $(call cmd,gen_ksymdeps)
245 $(call cmd,checkdoc)
246 $(call cmd,objtool)
247 $(call cmd,modversions_c)
248 $(call cmd,record_mcount)
249endef
250
251define rule_as_o_S
252 $(call cmd_and_fixdep,as_o_S)
253 $(call cmd,gen_ksymdeps)
254 $(call cmd,objtool)
255 $(call cmd,modversions_S)
256endef
257
258# List module undefined symbols (or empty line if not enabled)
259ifdef CONFIG_TRIM_UNUSED_KSYMS
260cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo
261else
262cmd_undef_syms = echo
263endif
264
265# Built-in and composite module parts
266$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
267 $(call cmd,force_checksrc)
268 $(call if_changed_rule,cc_o_c)
269
270cmd_mod = { \
271 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
272 $(cmd_undef_syms); \
273 } > $@
274
275$(obj)/%.mod: $(obj)/%.o FORCE
276 $(call if_changed,mod)
277
278targets += $(mod-targets)
279
280quiet_cmd_cc_lst_c = MKLST $@
281 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
282 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
283 System.map $(OBJDUMP) > $@
284
285$(obj)/%.lst: $(src)/%.c FORCE
286 $(call if_changed_dep,cc_lst_c)
287
288# Compile assembler sources (.S)
289# ---------------------------------------------------------------------------
290
291# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
292# or a file that it includes, in order to get versioned symbols. We build a
293# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
294# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
295#
296# This is convoluted. The .S file must first be preprocessed to run guards and
297# expand names, then the resulting exports must be constructed into plain
298# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
299# to make the genksyms input.
300#
301# These mirror gensymtypes_c and co above, keep them in synch.
302cmd_gensymtypes_S = \
303 { echo "\#include <linux/kernel.h>" ; \
304 echo "\#include <asm/asm-prototypes.h>" ; \
305 $(CPP) $(a_flags) $< | \
306 grep "\<___EXPORT_SYMBOL\>" | \
307 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
308 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
309 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
310 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
311 $(if $(KBUILD_PRESERVE),-p) \
312 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
313
314quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
315cmd_cc_symtypes_S = \
316 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
317 test -s $@ || rm -f $@
318
319$(obj)/%.symtypes : $(src)/%.S FORCE
320 $(call cmd,cc_symtypes_S)
321
322
323quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
324cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
325
326$(obj)/%.s: $(src)/%.S FORCE
327 $(call if_changed_dep,cpp_s_S)
328
329quiet_cmd_as_o_S = AS $(quiet_modtag) $@
330 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
331
332ifdef CONFIG_ASM_MODVERSIONS
333
334# versioning matches the C process described above, with difference that
335# we parse asm-prototypes.h C header to get function definitions.
336
337cmd_modversions_S = \
338 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
339 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
340 > $(@D)/.tmp_$(@F:.o=.ver); \
341 \
342 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
343 -T $(@D)/.tmp_$(@F:.o=.ver); \
344 mv -f $(@D)/.tmp_$(@F) $@; \
345 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
346 fi
347endif
348
349$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
350 $(call if_changed_rule,as_o_S)
351
352targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
353targets += $(extra-y) $(always-y) $(MAKECMDGOALS)
354
355# Linker scripts preprocessor (.lds.S -> .lds)
356# ---------------------------------------------------------------------------
357quiet_cmd_cpp_lds_S = LDS $@
358 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
359 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
360
361$(obj)/%.lds: $(src)/%.lds.S FORCE
362 $(call if_changed_dep,cpp_lds_S)
363
364# ASN.1 grammar
365# ---------------------------------------------------------------------------
366quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch]
367 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
368 $(basename $@).c $(basename $@).h
369
370$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
371 $(call cmd,asn1_compiler)
372
373# Build the compiled-in targets
374# ---------------------------------------------------------------------------
375
376# To build objects in subdirs, we need to descend into the directories
377$(obj)/%/built-in.a: $(obj)/% ;
378
379#
380# Rule to compile a set of .o files into one .a file (without symbol table)
381#
382ifdef builtin-target
383
384quiet_cmd_ar_builtin = AR $@
385 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs)
386
387$(builtin-target): $(real-obj-y) FORCE
388 $(call if_changed,ar_builtin)
389
390targets += $(builtin-target)
391endif # builtin-target
392
393#
394# Rule to create modules.order file
395#
396# Create commands to either record .ko file or cat modules.order from
397# a subdirectory
398$(modorder-target): $(subdir-ym) FORCE
399 $(Q){ $(foreach m, $(modorder), \
400 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \
401 | $(AWK) '!x[$$0]++' - > $@
402
403#
404# Rule to compile a set of .o files into one .a file (with symbol table)
405#
406ifdef lib-target
407
408$(lib-target): $(lib-y) FORCE
409 $(call if_changed,ar)
410
411targets += $(lib-target)
412
413dummy-object = $(obj)/.lib_exports.o
414ksyms-lds = $(dot-target).lds
415
416quiet_cmd_export_list = EXPORTS $@
417cmd_export_list = $(OBJDUMP) -h $< | \
418 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
419 rm -f $(dummy-object);\
420 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
421 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
422 rm $(dummy-object) $(ksyms-lds)
423
424$(obj)/lib-ksyms.o: $(lib-target) FORCE
425 $(call if_changed,export_list)
426
427targets += $(obj)/lib-ksyms.o
428
429endif
430
431# NOTE:
432# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
433# module is turned into a multi object module, $^ will contain header file
434# dependencies recorded in the .*.cmd file.
435quiet_cmd_link_multi-m = LD [M] $@
436 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
437
438$(multi-used-m): FORCE
439 $(call if_changed,link_multi-m)
440$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
441
442targets += $(multi-used-m)
443targets := $(filter-out $(PHONY), $(targets))
444
445# Add intermediate targets:
446# When building objects with specific suffix patterns, add intermediate
447# targets that the final targets are derived from.
448intermediate_targets = $(foreach sfx, $(2), \
449 $(patsubst %$(strip $(1)),%$(sfx), \
450 $(filter %$(strip $(1)), $(targets))))
451# %.asn1.o <- %.asn1.[ch] <- %.asn1
452# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
453# %.lex.o <- %.lex.c <- %.l
454# %.tab.o <- %.tab.[ch] <- %.y
455targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
456 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
457 $(call intermediate_targets, .lex.o, .lex.c) \
458 $(call intermediate_targets, .tab.o, .tab.c .tab.h)
459
460# Build
461# ---------------------------------------------------------------------------
462
463ifdef single-build
464
465KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS))
466
467curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \
468 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x))))
469
470# Handle single targets without any rule: show "Nothing to be done for ..." or
471# "No rule to make target ..." depending on whether the target exists.
472unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \
473 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS)))
474
475single-subdirs := $(foreach d, $(subdir-ym), \
476 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d)))
477
478__build: $(curdir-single) $(single-subdirs)
479ifneq ($(unknown-single),)
480 $(Q)$(MAKE) -f /dev/null $(unknown-single)
481endif
482 @:
483
484ifeq ($(curdir-single),)
485# Nothing to do in this directory. Do not include any .*.cmd file for speed-up
486targets :=
487else
488targets += $(curdir-single)
489endif
490
491else
492
493__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
494 $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \
495 $(subdir-ym) $(always-y)
496 @:
497
498endif
499
500# Descending
501# ---------------------------------------------------------------------------
502
503PHONY += $(subdir-ym)
504$(subdir-ym):
505 $(Q)$(MAKE) $(build)=$@ \
506 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
507 need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \
508 need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1))
509
510# Add FORCE to the prequisites of a target to force it to be always rebuilt.
511# ---------------------------------------------------------------------------
512
513PHONY += FORCE
514
515FORCE:
516
517# Read all saved command lines and dependencies for the $(targets) we
518# may be building above, using $(if_changed{,_dep}). As an
519# optimization, we don't need to read them if the target does not
520# exist, we will rebuild anyway in that case.
521
522existing-targets := $(wildcard $(sort $(targets)))
523
524-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
525
526ifdef building_out_of_srctree
527# Create directories for object files if they do not exist
528obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
529# If targets exist, their directories apparently exist. Skip mkdir.
530existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
531obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
532ifneq ($(obj-dirs),)
533$(shell mkdir -p $(obj-dirs))
534endif
535endif
536
537.PHONY: $(PHONY)