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