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 :=
19targets :=
20subdir-y :=
21subdir-m :=
22EXTRA_AFLAGS :=
23EXTRA_CFLAGS :=
24EXTRA_CPPFLAGS :=
25EXTRA_LDFLAGS :=
26asflags-y :=
27ccflags-y :=
28cppflags-y :=
29ldflags-y :=
30
31subdir-asflags-y :=
32subdir-ccflags-y :=
33
34# Read auto.conf if it exists, otherwise ignore
35-include include/config/auto.conf
36
37include scripts/Kbuild.include
38
39# The filename Kbuild has precedence over Makefile
40kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
41kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
42include $(kbuild-file)
43
44include scripts/Makefile.lib
45
46# Do not include host rules unless needed
47ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
48include scripts/Makefile.host
49endif
50
51ifndef obj
52$(warning kbuild: Makefile.build is included improperly)
53endif
54
55ifeq ($(need-modorder),)
56ifneq ($(obj-m),)
57$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
58$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
59endif
60endif
61
62# ===========================================================================
63
64ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
65lib-target := $(obj)/lib.a
66real-obj-y += $(obj)/lib-ksyms.o
67endif
68
69ifneq ($(strip $(real-obj-y) $(need-builtin)),)
70builtin-target := $(obj)/built-in.a
71endif
72
73ifeq ($(CONFIG_MODULES)$(need-modorder),y1)
74modorder-target := $(obj)/modules.order
75endif
76
77mod-targets := $(patsubst %.o, %.mod, $(obj-m))
78
79# Linus' kernel sanity checking tool
80ifeq ($(KBUILD_CHECKSRC),1)
81 quiet_cmd_checksrc = CHECK $<
82 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
83else ifeq ($(KBUILD_CHECKSRC),2)
84 quiet_cmd_force_checksrc = CHECK $<
85 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
86endif
87
88ifneq ($(KBUILD_EXTRA_WARN),)
89 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
90endif
91
92# Compile C sources (.c)
93# ---------------------------------------------------------------------------
94
95quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
96 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
97
98$(obj)/%.s: $(src)/%.c FORCE
99 $(call if_changed_dep,cc_s_c)
100
101quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
102cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
103
104$(obj)/%.i: $(src)/%.c FORCE
105 $(call if_changed_dep,cpp_i_c)
106
107# These mirror gensymtypes_S and co below, keep them in synch.
108cmd_gensymtypes_c = \
109 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
110 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
111 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
112 $(if $(KBUILD_PRESERVE),-p) \
113 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
114
115quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
116cmd_cc_symtypes_c = \
117 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \
118 test -s $@ || rm -f $@
119
120$(obj)/%.symtypes : $(src)/%.c FORCE
121 $(call cmd,cc_symtypes_c)
122
123# LLVM assembly
124# Generate .ll files from .c
125quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
126 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
127
128$(obj)/%.ll: $(src)/%.c FORCE
129 $(call if_changed_dep,cc_ll_c)
130
131# C (.c) files
132# The C file is compiled and updated dependency information is generated.
133# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
134
135quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
136 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
137
138ifdef CONFIG_MODVERSIONS
139# When module versioning is enabled the following steps are executed:
140# o compile a <file>.o from <file>.c
141# o if <file>.o doesn't contain a __ksymtab version, i.e. does
142# not export symbols, it's done.
143# o otherwise, we calculate symbol versions using the good old
144# genksyms on the preprocessed source and postprocess them in a way
145# that they are usable as a linker script
146# o generate .tmp_<file>.o from <file>.o using the linker to
147# replace the unresolved symbols __crc_exported_symbol with
148# the actual value of the checksum generated by genksyms
149# o remove .tmp_<file>.o to <file>.o
150
151cmd_modversions_c = \
152 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
153 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
154 > $(@D)/.tmp_$(@F:.o=.ver); \
155 \
156 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
157 -T $(@D)/.tmp_$(@F:.o=.ver); \
158 mv -f $(@D)/.tmp_$(@F) $@; \
159 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
160 fi
161endif
162
163ifdef CONFIG_FTRACE_MCOUNT_RECORD
164ifndef CC_USING_RECORD_MCOUNT
165# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
166ifdef BUILD_C_RECORDMCOUNT
167ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
168 RECORDMCOUNT_FLAGS = -w
169endif
170# Due to recursion, we must skip empty.o.
171# The empty.o file is created in the make process in order to determine
172# the target endianness and word size. It is made before all other C
173# files, including recordmcount.
174sub_cmd_record_mcount = \
175 if [ $(@) != "scripts/mod/empty.o" ]; then \
176 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
177 fi;
178recordmcount_source := $(srctree)/scripts/recordmcount.c \
179 $(srctree)/scripts/recordmcount.h
180else
181sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
182 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
183 "$(if $(CONFIG_64BIT),64,32)" \
184 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
185 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
186 "$(if $(part-of-module),1,0)" "$(@)";
187recordmcount_source := $(srctree)/scripts/recordmcount.pl
188endif # BUILD_C_RECORDMCOUNT
189cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
190 $(sub_cmd_record_mcount))
191endif # CC_USING_RECORD_MCOUNT
192endif # CONFIG_FTRACE_MCOUNT_RECORD
193
194ifdef CONFIG_STACK_VALIDATION
195ifneq ($(SKIP_STACK_VALIDATION),1)
196
197__objtool_obj := $(objtree)/tools/objtool/objtool
198
199objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
200
201objtool_args += $(if $(part-of-module), --module,)
202
203ifndef CONFIG_FRAME_POINTER
204objtool_args += --no-fp
205endif
206ifdef CONFIG_GCOV_KERNEL
207objtool_args += --no-unreachable
208endif
209ifdef CONFIG_RETPOLINE
210 objtool_args += --retpoline
211endif
212ifdef CONFIG_X86_SMAP
213 objtool_args += --uaccess
214endif
215
216# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
217# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
218# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
219cmd_objtool = $(if $(patsubst y%,, \
220 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
221 $(__objtool_obj) $(objtool_args) $@)
222objtool_obj = $(if $(patsubst y%,, \
223 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
224 $(__objtool_obj))
225
226endif # SKIP_STACK_VALIDATION
227endif # CONFIG_STACK_VALIDATION
228
229# Rebuild all objects when objtool changes, or is enabled/disabled.
230objtool_dep = $(objtool_obj) \
231 $(wildcard include/config/orc/unwinder.h \
232 include/config/stack/validation.h)
233
234ifdef CONFIG_TRIM_UNUSED_KSYMS
235cmd_gen_ksymdeps = \
236 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
237endif
238
239define rule_cc_o_c
240 $(call cmd,checksrc)
241 $(call cmd_and_fixdep,cc_o_c)
242 $(call cmd,gen_ksymdeps)
243 $(call cmd,checkdoc)
244 $(call cmd,objtool)
245 $(call cmd,modversions_c)
246 $(call cmd,record_mcount)
247endef
248
249define rule_as_o_S
250 $(call cmd_and_fixdep,as_o_S)
251 $(call cmd,gen_ksymdeps)
252 $(call cmd,objtool)
253 $(call cmd,modversions_S)
254endef
255
256# List module undefined symbols (or empty line if not enabled)
257ifdef CONFIG_TRIM_UNUSED_KSYMS
258cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo
259else
260cmd_undef_syms = echo
261endif
262
263# Built-in and composite module parts
264$(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
265 $(call cmd,force_checksrc)
266 $(call if_changed_rule,cc_o_c)
267
268cmd_mod = { \
269 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
270 $(cmd_undef_syms); \
271 } > $@
272
273$(obj)/%.mod: $(obj)/%.o FORCE
274 $(call if_changed,mod)
275
276targets += $(mod-targets)
277
278quiet_cmd_cc_lst_c = MKLST $@
279 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
280 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
281 System.map $(OBJDUMP) > $@
282
283$(obj)/%.lst: $(src)/%.c FORCE
284 $(call if_changed_dep,cc_lst_c)
285
286# Compile assembler sources (.S)
287# ---------------------------------------------------------------------------
288
289# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
290# or a file that it includes, in order to get versioned symbols. We build a
291# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
292# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
293#
294# This is convoluted. The .S file must first be preprocessed to run guards and
295# expand names, then the resulting exports must be constructed into plain
296# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
297# to make the genksyms input.
298#
299# These mirror gensymtypes_c and co above, keep them in synch.
300cmd_gensymtypes_S = \
301 { echo "\#include <linux/kernel.h>" ; \
302 echo "\#include <asm/asm-prototypes.h>" ; \
303 $(CPP) $(a_flags) $< | \
304 grep "\<___EXPORT_SYMBOL\>" | \
305 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
306 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
307 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
308 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
309 $(if $(KBUILD_PRESERVE),-p) \
310 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
311
312quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
313cmd_cc_symtypes_S = \
314 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
315 test -s $@ || rm -f $@
316
317$(obj)/%.symtypes : $(src)/%.S FORCE
318 $(call cmd,cc_symtypes_S)
319
320
321quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
322cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
323
324$(obj)/%.s: $(src)/%.S FORCE
325 $(call if_changed_dep,cpp_s_S)
326
327quiet_cmd_as_o_S = AS $(quiet_modtag) $@
328 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
329
330ifdef CONFIG_ASM_MODVERSIONS
331
332# versioning matches the C process described above, with difference that
333# we parse asm-prototypes.h C header to get function definitions.
334
335cmd_modversions_S = \
336 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
337 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
338 > $(@D)/.tmp_$(@F:.o=.ver); \
339 \
340 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
341 -T $(@D)/.tmp_$(@F:.o=.ver); \
342 mv -f $(@D)/.tmp_$(@F) $@; \
343 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
344 fi
345endif
346
347$(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
348 $(call if_changed_rule,as_o_S)
349
350targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
351targets += $(extra-y) $(MAKECMDGOALS) $(always)
352
353# Linker scripts preprocessor (.lds.S -> .lds)
354# ---------------------------------------------------------------------------
355quiet_cmd_cpp_lds_S = LDS $@
356 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
357 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
358
359$(obj)/%.lds: $(src)/%.lds.S FORCE
360 $(call if_changed_dep,cpp_lds_S)
361
362# ASN.1 grammar
363# ---------------------------------------------------------------------------
364quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch]
365 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
366 $(basename $@).c $(basename $@).h
367
368$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
369 $(call cmd,asn1_compiler)
370
371# Build the compiled-in targets
372# ---------------------------------------------------------------------------
373
374# To build objects in subdirs, we need to descend into the directories
375$(sort $(subdir-obj-y)): $(subdir-ym) ;
376
377#
378# Rule to compile a set of .o files into one .a file (without symbol table)
379#
380ifdef builtin-target
381
382quiet_cmd_ar_builtin = AR $@
383 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs)
384
385$(builtin-target): $(real-obj-y) FORCE
386 $(call if_changed,ar_builtin)
387
388targets += $(builtin-target)
389endif # builtin-target
390
391#
392# Rule to create modules.order file
393#
394# Create commands to either record .ko file or cat modules.order from
395# a subdirectory
396$(modorder-target): $(subdir-ym) FORCE
397 $(Q){ $(foreach m, $(modorder), \
398 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \
399 | $(AWK) '!x[$$0]++' - > $@
400
401#
402# Rule to compile a set of .o files into one .a file (with symbol table)
403#
404ifdef lib-target
405
406$(lib-target): $(lib-y) FORCE
407 $(call if_changed,ar)
408
409targets += $(lib-target)
410
411dummy-object = $(obj)/.lib_exports.o
412ksyms-lds = $(dot-target).lds
413
414quiet_cmd_export_list = EXPORTS $@
415cmd_export_list = $(OBJDUMP) -h $< | \
416 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
417 rm -f $(dummy-object);\
418 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
419 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
420 rm $(dummy-object) $(ksyms-lds)
421
422$(obj)/lib-ksyms.o: $(lib-target) FORCE
423 $(call if_changed,export_list)
424
425targets += $(obj)/lib-ksyms.o
426
427endif
428
429# NOTE:
430# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
431# module is turned into a multi object module, $^ will contain header file
432# dependencies recorded in the .*.cmd file.
433quiet_cmd_link_multi-m = LD [M] $@
434 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
435
436$(multi-used-m): FORCE
437 $(call if_changed,link_multi-m)
438$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
439
440targets += $(multi-used-m)
441targets := $(filter-out $(PHONY), $(targets))
442
443# Add intermediate targets:
444# When building objects with specific suffix patterns, add intermediate
445# targets that the final targets are derived from.
446intermediate_targets = $(foreach sfx, $(2), \
447 $(patsubst %$(strip $(1)),%$(sfx), \
448 $(filter %$(strip $(1)), $(targets))))
449# %.asn1.o <- %.asn1.[ch] <- %.asn1
450# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
451# %.lex.o <- %.lex.c <- %.l
452# %.tab.o <- %.tab.[ch] <- %.y
453targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
454 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
455 $(call intermediate_targets, .lex.o, .lex.c) \
456 $(call intermediate_targets, .tab.o, .tab.c .tab.h)
457
458# Build
459# ---------------------------------------------------------------------------
460
461ifdef single-build
462
463KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS))
464
465curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \
466 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x))))
467
468# Handle single targets without any rule: show "Nothing to be done for ..." or
469# "No rule to make target ..." depending on whether the target exists.
470unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \
471 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS)))
472
473single-subdirs := $(foreach d, $(subdir-ym), \
474 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d)))
475
476__build: $(curdir-single) $(single-subdirs)
477ifneq ($(unknown-single),)
478 $(Q)$(MAKE) -f /dev/null $(unknown-single)
479endif
480 @:
481
482ifeq ($(curdir-single),)
483# Nothing to do in this directory. Do not include any .*.cmd file for speed-up
484targets :=
485else
486targets += $(curdir-single)
487endif
488
489else
490
491__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
492 $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \
493 $(subdir-ym) $(always)
494 @:
495
496endif
497
498# Descending
499# ---------------------------------------------------------------------------
500
501PHONY += $(subdir-ym)
502$(subdir-ym):
503 $(Q)$(MAKE) $(build)=$@ \
504 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
505 need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \
506 need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1))
507
508# Add FORCE to the prequisites of a target to force it to be always rebuilt.
509# ---------------------------------------------------------------------------
510
511PHONY += FORCE
512
513FORCE:
514
515# Read all saved command lines and dependencies for the $(targets) we
516# may be building above, using $(if_changed{,_dep}). As an
517# optimization, we don't need to read them if the target does not
518# exist, we will rebuild anyway in that case.
519
520existing-targets := $(wildcard $(sort $(targets)))
521
522-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
523
524ifdef building_out_of_srctree
525# Create directories for object files if they do not exist
526obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
527# If targets exist, their directories apparently exist. Skip mkdir.
528existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
529obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
530ifneq ($(obj-dirs),)
531$(shell mkdir -p $(obj-dirs))
532endif
533endif
534
535.PHONY: $(PHONY)