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1# SPDX-License-Identifier: GPL-2.0
2# ==========================================================================
3# Building
4# ==========================================================================
5
6src := $(obj)
7
8PHONY := $(obj)/
9$(obj)/:
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-y :=
19always-m :=
20targets :=
21subdir-y :=
22subdir-m :=
23EXTRA_AFLAGS :=
24EXTRA_CFLAGS :=
25EXTRA_CPPFLAGS :=
26EXTRA_LDFLAGS :=
27asflags-y :=
28ccflags-y :=
29rustflags-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 $(srctree)/scripts/Kbuild.include
40include $(srctree)/scripts/Makefile.compiler
41include $(kbuild-file)
42include $(srctree)/scripts/Makefile.lib
43
44# Do not include hostprogs rules unless needed.
45# $(sort ...) is used here to remove duplicated words and excessive spaces.
46hostprogs := $(sort $(hostprogs))
47ifneq ($(hostprogs),)
48include $(srctree)/scripts/Makefile.host
49endif
50
51# Do not include userprogs rules unless needed.
52# $(sort ...) is used here to remove duplicated words and excessive spaces.
53userprogs := $(sort $(userprogs))
54ifneq ($(userprogs),)
55include $(srctree)/scripts/Makefile.userprogs
56endif
57
58ifndef obj
59$(warning kbuild: Makefile.build is included improperly)
60endif
61
62ifeq ($(need-modorder),)
63ifneq ($(obj-m),)
64$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
65$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
66endif
67endif
68
69# ===========================================================================
70
71# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...)
72subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y)))
73subdir-modorder := $(sort $(filter %/modules.order, $(obj-m)))
74
75targets-for-builtin := $(extra-y)
76
77ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
78targets-for-builtin += $(obj)/lib.a
79endif
80
81ifdef need-builtin
82targets-for-builtin += $(obj)/built-in.a
83endif
84
85targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usyms), \
86 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m))))
87
88ifdef need-modorder
89targets-for-modules += $(obj)/modules.order
90endif
91
92targets += $(targets-for-builtin) $(targets-for-modules)
93
94# Linus' kernel sanity checking tool
95ifeq ($(KBUILD_CHECKSRC),1)
96 quiet_cmd_checksrc = CHECK $<
97 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
98else ifeq ($(KBUILD_CHECKSRC),2)
99 quiet_cmd_force_checksrc = CHECK $<
100 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
101endif
102
103ifneq ($(KBUILD_EXTRA_WARN),)
104 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
105endif
106
107# Compile C sources (.c)
108# ---------------------------------------------------------------------------
109
110quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
111 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $<
112
113$(obj)/%.s: $(src)/%.c FORCE
114 $(call if_changed_dep,cc_s_c)
115
116quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
117cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
118
119$(obj)/%.i: $(src)/%.c FORCE
120 $(call if_changed_dep,cpp_i_c)
121
122genksyms = scripts/genksyms/genksyms \
123 $(if $(1), -T $(2)) \
124 $(if $(KBUILD_PRESERVE), -p) \
125 -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null)
126
127# These mirror gensymtypes_S and co below, keep them in synch.
128cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms)
129
130quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
131 cmd_cc_symtypes_c = $(call cmd_gensymtypes_c,true,$@) >/dev/null
132
133$(obj)/%.symtypes : $(src)/%.c FORCE
134 $(call cmd,cc_symtypes_c)
135
136# LLVM assembly
137# Generate .ll files from .c
138quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
139 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
140
141$(obj)/%.ll: $(src)/%.c FORCE
142 $(call if_changed_dep,cc_ll_c)
143
144# C (.c) files
145# The C file is compiled and updated dependency information is generated.
146# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
147
148is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y)
149
150# When a module consists of a single object, there is no reason to keep LLVM IR.
151# Make $(LD) covert LLVM IR to ELF here.
152ifdef CONFIG_LTO_CLANG
153cmd_ld_single_m = $(if $(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@)
154endif
155
156quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
157 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \
158 $(cmd_ld_single_m) \
159 $(cmd_objtool)
160
161ifdef CONFIG_MODVERSIONS
162# When module versioning is enabled the following steps are executed:
163# o compile a <file>.o from <file>.c
164# o if <file>.o doesn't contain a __ksymtab version, i.e. does
165# not export symbols, it's done.
166# o otherwise, we calculate symbol versions using the good old
167# genksyms on the preprocessed source and dump them into the .cmd file.
168# o modpost will extract versions from that file and create *.c files that will
169# be compiled and linked to the kernel and/or modules.
170
171gen_symversions = \
172 if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \
173 $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
174 >> $(dot-target).cmd; \
175 fi
176
177cmd_gen_symversions_c = $(call gen_symversions,c)
178
179endif
180
181ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
182# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
183ifdef BUILD_C_RECORDMCOUNT
184ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
185 RECORDMCOUNT_FLAGS = -w
186endif
187# Due to recursion, we must skip empty.o.
188# The empty.o file is created in the make process in order to determine
189# the target endianness and word size. It is made before all other C
190# files, including recordmcount.
191sub_cmd_record_mcount = \
192 if [ $(@) != "scripts/mod/empty.o" ]; then \
193 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
194 fi;
195recordmcount_source := $(srctree)/scripts/recordmcount.c \
196 $(srctree)/scripts/recordmcount.h
197else
198sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
199 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
200 "$(if $(CONFIG_64BIT),64,32)" \
201 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
202 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
203 "$(if $(part-of-module),1,0)" "$(@)";
204recordmcount_source := $(srctree)/scripts/recordmcount.pl
205endif # BUILD_C_RECORDMCOUNT
206cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
207 $(sub_cmd_record_mcount))
208endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
209
210# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
211# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
212# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
213
214is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y)
215
216$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))
217
218ifdef CONFIG_TRIM_UNUSED_KSYMS
219cmd_gen_ksymdeps = \
220 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
221endif
222
223cmd_check_local_export = $(srctree)/scripts/check-local-export $@
224
225ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
226cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi)))
227endif
228
229define rule_cc_o_c
230 $(call cmd_and_fixdep,cc_o_c)
231 $(call cmd,gen_ksymdeps)
232 $(call cmd,check_local_export)
233 $(call cmd,checksrc)
234 $(call cmd,checkdoc)
235 $(call cmd,gen_objtooldep)
236 $(call cmd,gen_symversions_c)
237 $(call cmd,record_mcount)
238 $(call cmd,warn_shared_object)
239endef
240
241define rule_as_o_S
242 $(call cmd_and_fixdep,as_o_S)
243 $(call cmd,gen_ksymdeps)
244 $(call cmd,check_local_export)
245 $(call cmd,gen_objtooldep)
246 $(call cmd,gen_symversions_S)
247 $(call cmd,warn_shared_object)
248endef
249
250# Built-in and composite module parts
251$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
252 $(call if_changed_rule,cc_o_c)
253 $(call cmd,force_checksrc)
254
255# To make this rule robust against "Argument list too long" error,
256# ensure to add $(obj)/ prefix by a shell command.
257cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \
258 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@
259
260$(obj)/%.mod: FORCE
261 $(call if_changed,mod)
262
263# List module undefined symbols
264cmd_undefined_syms = $(NM) $< | sed -n 's/^ *U //p' > $@
265
266$(obj)/%.usyms: $(obj)/%.o FORCE
267 $(call if_changed,undefined_syms)
268
269quiet_cmd_cc_lst_c = MKLST $@
270 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
271 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
272 System.map $(OBJDUMP) > $@
273
274$(obj)/%.lst: $(src)/%.c FORCE
275 $(call if_changed_dep,cc_lst_c)
276
277# Compile Rust sources (.rs)
278# ---------------------------------------------------------------------------
279
280rust_allowed_features := core_ffi_c
281
282rust_common_cmd = \
283 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
284 -Zallow-features=$(rust_allowed_features) \
285 -Zcrate-attr=no_std \
286 -Zcrate-attr='feature($(rust_allowed_features))' \
287 --extern alloc --extern kernel \
288 --crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \
289 --crate-name $(basename $(notdir $@))
290
291rust_handle_depfile = \
292 mv $(obj)/$(basename $(notdir $@)).d $(depfile); \
293 sed -i '/^\#/d' $(depfile)
294
295# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
296# will be used. We explicitly request `-Ccodegen-units=1` in any case, and
297# the compiler shows a warning if it is not 1. However, if we ever stop
298# requesting it explicitly and we start using some other `--emit` that does not
299# imply it (and for which codegen is performed), then we would be out of sync,
300# i.e. the outputs we would get for the different single targets (e.g. `.ll`)
301# would not match each other.
302
303quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
304 cmd_rustc_o_rs = \
305 $(rust_common_cmd) --emit=dep-info,obj $<; \
306 $(rust_handle_depfile)
307
308$(obj)/%.o: $(src)/%.rs FORCE
309 $(call if_changed_dep,rustc_o_rs)
310
311quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
312 cmd_rustc_rsi_rs = \
313 $(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \
314 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \
315 $(rust_handle_depfile)
316
317$(obj)/%.rsi: $(src)/%.rs FORCE
318 $(call if_changed_dep,rustc_rsi_rs)
319
320quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
321 cmd_rustc_s_rs = \
322 $(rust_common_cmd) --emit=dep-info,asm $<; \
323 $(rust_handle_depfile)
324
325$(obj)/%.s: $(src)/%.rs FORCE
326 $(call if_changed_dep,rustc_s_rs)
327
328quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
329 cmd_rustc_ll_rs = \
330 $(rust_common_cmd) --emit=dep-info,llvm-ir $<; \
331 $(rust_handle_depfile)
332
333$(obj)/%.ll: $(src)/%.rs FORCE
334 $(call if_changed_dep,rustc_ll_rs)
335
336# Compile assembler sources (.S)
337# ---------------------------------------------------------------------------
338
339# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
340# or a file that it includes, in order to get versioned symbols. We build a
341# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
342# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
343#
344# This is convoluted. The .S file must first be preprocessed to run guards and
345# expand names, then the resulting exports must be constructed into plain
346# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
347# to make the genksyms input.
348#
349# These mirror gensymtypes_c and co above, keep them in synch.
350cmd_gensymtypes_S = \
351 { echo "\#include <linux/kernel.h>" ; \
352 echo "\#include <asm/asm-prototypes.h>" ; \
353 $(CPP) $(a_flags) $< | \
354 grep "\<___EXPORT_SYMBOL\>" | \
355 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
356 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms)
357
358quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
359 cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null
360
361$(obj)/%.symtypes : $(src)/%.S FORCE
362 $(call cmd,cc_symtypes_S)
363
364
365quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
366cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
367
368$(obj)/%.s: $(src)/%.S FORCE
369 $(call if_changed_dep,cpp_s_S)
370
371quiet_cmd_as_o_S = AS $(quiet_modtag) $@
372 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool)
373
374ifdef CONFIG_ASM_MODVERSIONS
375
376# versioning matches the C process described above, with difference that
377# we parse asm-prototypes.h C header to get function definitions.
378
379cmd_gen_symversions_S = $(call gen_symversions,S)
380
381endif
382
383$(obj)/%.o: $(src)/%.S FORCE
384 $(call if_changed_rule,as_o_S)
385
386targets += $(filter-out $(subdir-builtin), $(real-obj-y))
387targets += $(filter-out $(subdir-modorder), $(real-obj-m))
388targets += $(real-dtb-y) $(lib-y) $(always-y)
389
390# Linker scripts preprocessor (.lds.S -> .lds)
391# ---------------------------------------------------------------------------
392quiet_cmd_cpp_lds_S = LDS $@
393 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
394 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
395
396$(obj)/%.lds: $(src)/%.lds.S FORCE
397 $(call if_changed_dep,cpp_lds_S)
398
399# ASN.1 grammar
400# ---------------------------------------------------------------------------
401quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch]
402 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
403 $(basename $@).c $(basename $@).h
404
405$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
406 $(call cmd,asn1_compiler)
407
408# Build the compiled-in targets
409# ---------------------------------------------------------------------------
410
411# To build objects in subdirs, we need to descend into the directories
412$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;
413$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
414
415#
416# Rule to compile a set of .o files into one .a file (without symbol table)
417#
418# To make this rule robust against "Argument list too long" error,
419# remove $(obj)/ prefix, and restore it by a shell command.
420
421quiet_cmd_ar_builtin = AR $@
422 cmd_ar_builtin = rm -f $@; \
423 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \
424 $(AR) cDPrST $@
425
426$(obj)/built-in.a: $(real-obj-y) FORCE
427 $(call if_changed,ar_builtin)
428
429#
430# Rule to create modules.order file
431#
432# Create commands to either record .ko file or cat modules.order from
433# a subdirectory
434# Add $(obj-m) as the prerequisite to avoid updating the timestamp of
435# modules.order unless contained modules are updated.
436
437cmd_modules_order = { $(foreach m, $(real-prereqs), \
438 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \
439 > $@
440
441$(obj)/modules.order: $(obj-m) FORCE
442 $(call if_changed,modules_order)
443
444#
445# Rule to compile a set of .o files into one .a file (with symbol table)
446#
447
448$(obj)/lib.a: $(lib-y) FORCE
449 $(call if_changed,ar)
450
451quiet_cmd_ld_multi_m = LD [M] $@
452 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$(patsubst %.o,%.mod,$@) $(cmd_objtool)
453
454define rule_ld_multi_m
455 $(call cmd_and_savecmd,ld_multi_m)
456 $(call cmd,gen_objtooldep)
457endef
458
459$(multi-obj-m): objtool-enabled := $(delay-objtool)
460$(multi-obj-m): part-of-module := y
461$(multi-obj-m): %.o: %.mod FORCE
462 $(call if_changed_rule,ld_multi_m)
463$(call multi_depend, $(multi-obj-m), .o, -objs -y -m)
464
465# Add intermediate targets:
466# When building objects with specific suffix patterns, add intermediate
467# targets that the final targets are derived from.
468intermediate_targets = $(foreach sfx, $(2), \
469 $(patsubst %$(strip $(1)),%$(sfx), \
470 $(filter %$(strip $(1)), $(targets))))
471# %.asn1.o <- %.asn1.[ch] <- %.asn1
472# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
473# %.dtbo.o <- %.dtbo.S <- %.dtbo <- %.dtso
474# %.lex.o <- %.lex.c <- %.l
475# %.tab.o <- %.tab.[ch] <- %.y
476targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
477 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
478 $(call intermediate_targets, .dtbo.o, .dtbo.S .dtbo) \
479 $(call intermediate_targets, .lex.o, .lex.c) \
480 $(call intermediate_targets, .tab.o, .tab.c .tab.h)
481
482# Build
483# ---------------------------------------------------------------------------
484
485$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \
486 $(if $(KBUILD_MODULES), $(targets-for-modules)) \
487 $(subdir-ym) $(always-y)
488 @:
489
490# Single targets
491# ---------------------------------------------------------------------------
492
493single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d))
494single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS))
495
496$(single-subdir-goals): $(single-subdirs)
497 @:
498
499# Descending
500# ---------------------------------------------------------------------------
501
502PHONY += $(subdir-ym)
503$(subdir-ym):
504 $(Q)$(MAKE) $(build)=$@ \
505 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \
506 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \
507 $(filter $@/%, $(single-subdir-goals))
508
509# Add FORCE to the prequisites of a target to force it to be always rebuilt.
510# ---------------------------------------------------------------------------
511
512PHONY += FORCE
513
514FORCE:
515
516targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS))
517targets := $(filter-out $(PHONY), $(targets))
518
519# Read all saved command lines and dependencies for the $(targets) we
520# may be building above, using $(if_changed{,_dep}). As an
521# optimization, we don't need to read them if the target does not
522# exist, we will rebuild anyway in that case.
523
524existing-targets := $(wildcard $(sort $(targets)))
525
526-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
527
528# Create directories for object files if they do not exist
529obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets))))
530# If targets exist, their directories apparently exist. Skip mkdir.
531existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
532obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
533ifneq ($(obj-dirs),)
534$(shell mkdir -p $(obj-dirs))
535endif
536
537.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-y :=
19always-m :=
20targets :=
21subdir-y :=
22subdir-m :=
23EXTRA_AFLAGS :=
24EXTRA_CFLAGS :=
25EXTRA_CPPFLAGS :=
26EXTRA_LDFLAGS :=
27asflags-y :=
28ccflags-y :=
29cppflags-y :=
30ldflags-y :=
31
32subdir-asflags-y :=
33subdir-ccflags-y :=
34
35# Read auto.conf if it exists, otherwise ignore
36-include include/config/auto.conf
37
38include $(srctree)/scripts/Kbuild.include
39include $(srctree)/scripts/Makefile.compiler
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 $(srctree)/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 $(srctree)/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 $(srctree)/scripts/Makefile.userprogs
60endif
61
62ifndef obj
63$(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) $(CC_FLAGS_LTO), $(c_flags)) -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
169ifdef CONFIG_LTO_CLANG
170# Generate .o.symversions files for each .o with exported symbols, and link these
171# to the kernel and/or modules at the end.
172cmd_modversions_c = \
173 if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \
174 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
175 > $@.symversions; \
176 fi;
177else
178cmd_modversions_c = \
179 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
180 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
181 > $(@D)/.tmp_$(@F:.o=.ver); \
182 \
183 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
184 -T $(@D)/.tmp_$(@F:.o=.ver); \
185 mv -f $(@D)/.tmp_$(@F) $@; \
186 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
187 fi
188endif
189endif
190
191ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
192# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
193ifdef BUILD_C_RECORDMCOUNT
194ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
195 RECORDMCOUNT_FLAGS = -w
196endif
197# Due to recursion, we must skip empty.o.
198# The empty.o file is created in the make process in order to determine
199# the target endianness and word size. It is made before all other C
200# files, including recordmcount.
201sub_cmd_record_mcount = \
202 if [ $(@) != "scripts/mod/empty.o" ]; then \
203 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
204 fi;
205recordmcount_source := $(srctree)/scripts/recordmcount.c \
206 $(srctree)/scripts/recordmcount.h
207else
208sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
209 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
210 "$(if $(CONFIG_64BIT),64,32)" \
211 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
212 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
213 "$(if $(part-of-module),1,0)" "$(@)";
214recordmcount_source := $(srctree)/scripts/recordmcount.pl
215endif # BUILD_C_RECORDMCOUNT
216cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
217 $(sub_cmd_record_mcount))
218endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
219
220ifdef CONFIG_STACK_VALIDATION
221ifndef CONFIG_LTO_CLANG
222
223__objtool_obj := $(objtree)/tools/objtool/objtool
224
225# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
226# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
227# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
228cmd_objtool = $(if $(patsubst y%,, \
229 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
230 $(__objtool_obj) $(objtool_args) $@)
231objtool_obj = $(if $(patsubst y%,, \
232 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
233 $(__objtool_obj))
234
235endif # CONFIG_LTO_CLANG
236endif # CONFIG_STACK_VALIDATION
237
238# Rebuild all objects when objtool changes, or is enabled/disabled.
239objtool_dep = $(objtool_obj) \
240 $(wildcard include/config/ORC_UNWINDER \
241 include/config/STACK_VALIDATION)
242
243ifdef CONFIG_TRIM_UNUSED_KSYMS
244cmd_gen_ksymdeps = \
245 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
246
247# List module undefined symbols
248undefined_syms = $(NM) $< | $(AWK) '$$1 == "U" { printf("%s%s", x++ ? " " : "", $$2) }';
249endif
250
251define rule_cc_o_c
252 $(call cmd_and_fixdep,cc_o_c)
253 $(call cmd,gen_ksymdeps)
254 $(call cmd,checksrc)
255 $(call cmd,checkdoc)
256 $(call cmd,objtool)
257 $(call cmd,modversions_c)
258 $(call cmd,record_mcount)
259endef
260
261define rule_as_o_S
262 $(call cmd_and_fixdep,as_o_S)
263 $(call cmd,gen_ksymdeps)
264 $(call cmd,objtool)
265 $(call cmd,modversions_S)
266endef
267
268# Built-in and composite module parts
269.SECONDEXPANSION:
270$(obj)/%.o: $(src)/%.c $(recordmcount_source) $$(objtool_dep) FORCE
271 $(call if_changed_rule,cc_o_c)
272 $(call cmd,force_checksrc)
273
274cmd_mod = { \
275 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
276 $(undefined_syms) echo; \
277 } > $@
278
279$(obj)/%.mod: $(obj)/%.o FORCE
280 $(call if_changed,mod)
281
282quiet_cmd_cc_lst_c = MKLST $@
283 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
284 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
285 System.map $(OBJDUMP) > $@
286
287$(obj)/%.lst: $(src)/%.c FORCE
288 $(call if_changed_dep,cc_lst_c)
289
290# Compile assembler sources (.S)
291# ---------------------------------------------------------------------------
292
293# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
294# or a file that it includes, in order to get versioned symbols. We build a
295# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
296# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
297#
298# This is convoluted. The .S file must first be preprocessed to run guards and
299# expand names, then the resulting exports must be constructed into plain
300# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
301# to make the genksyms input.
302#
303# These mirror gensymtypes_c and co above, keep them in synch.
304cmd_gensymtypes_S = \
305 { echo "\#include <linux/kernel.h>" ; \
306 echo "\#include <asm/asm-prototypes.h>" ; \
307 $(CPP) $(a_flags) $< | \
308 grep "\<___EXPORT_SYMBOL\>" | \
309 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
310 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
311 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
312 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
313 $(if $(KBUILD_PRESERVE),-p) \
314 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
315
316quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
317cmd_cc_symtypes_S = \
318 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
319 test -s $@ || rm -f $@
320
321$(obj)/%.symtypes : $(src)/%.S FORCE
322 $(call cmd,cc_symtypes_S)
323
324
325quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
326cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
327
328$(obj)/%.s: $(src)/%.S FORCE
329 $(call if_changed_dep,cpp_s_S)
330
331quiet_cmd_as_o_S = AS $(quiet_modtag) $@
332 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
333
334ifdef CONFIG_ASM_MODVERSIONS
335
336# versioning matches the C process described above, with difference that
337# we parse asm-prototypes.h C header to get function definitions.
338
339cmd_modversions_S = \
340 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
341 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
342 > $(@D)/.tmp_$(@F:.o=.ver); \
343 \
344 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
345 -T $(@D)/.tmp_$(@F:.o=.ver); \
346 mv -f $(@D)/.tmp_$(@F) $@; \
347 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
348 fi
349endif
350
351$(obj)/%.o: $(src)/%.S $$(objtool_dep) FORCE
352 $(call if_changed_rule,as_o_S)
353
354targets += $(filter-out $(subdir-builtin), $(real-obj-y))
355targets += $(filter-out $(subdir-modorder), $(real-obj-m))
356targets += $(real-dtb-y) $(lib-y) $(always-y) $(MAKECMDGOALS)
357
358# Linker scripts preprocessor (.lds.S -> .lds)
359# ---------------------------------------------------------------------------
360quiet_cmd_cpp_lds_S = LDS $@
361 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
362 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
363
364$(obj)/%.lds: $(src)/%.lds.S FORCE
365 $(call if_changed_dep,cpp_lds_S)
366
367# ASN.1 grammar
368# ---------------------------------------------------------------------------
369quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch]
370 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
371 $(basename $@).c $(basename $@).h
372
373$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
374 $(call cmd,asn1_compiler)
375
376# Build the compiled-in targets
377# ---------------------------------------------------------------------------
378
379# To build objects in subdirs, we need to descend into the directories
380$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;
381$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
382
383# combine symversions for later processing
384quiet_cmd_update_lto_symversions = SYMVER $@
385ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y)
386 cmd_update_lto_symversions = \
387 rm -f $@.symversions \
388 $(foreach n, $(filter-out FORCE,$^), \
389 $(if $(shell test -s $(n).symversions && echo y), \
390 ; cat $(n).symversions >> $@.symversions))
391else
392 cmd_update_lto_symversions = echo >/dev/null
393endif
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
402quiet_cmd_ar_and_symver = AR $@
403 cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin)
404
405$(obj)/built-in.a: $(real-obj-y) FORCE
406 $(call if_changed,ar_and_symver)
407
408#
409# Rule to create modules.order file
410#
411# Create commands to either record .ko file or cat modules.order from
412# a subdirectory
413# Add $(obj-m) as the prerequisite to avoid updating the timestamp of
414# modules.order unless contained modules are updated.
415
416cmd_modules_order = { $(foreach m, $(real-prereqs), \
417 $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \
418 | $(AWK) '!x[$$0]++' - > $@
419
420$(obj)/modules.order: $(obj-m) FORCE
421 $(call if_changed,modules_order)
422
423#
424# Rule to compile a set of .o files into one .a file (with symbol table)
425#
426quiet_cmd_ar_lib = AR $@
427 cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar)
428
429$(obj)/lib.a: $(lib-y) FORCE
430 $(call if_changed,ar_lib)
431
432# NOTE:
433# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
434# module is turned into a multi object module, $^ will contain header file
435# dependencies recorded in the .*.cmd file.
436ifdef CONFIG_LTO_CLANG
437quiet_cmd_link_multi-m = AR [M] $@
438cmd_link_multi-m = \
439 $(cmd_update_lto_symversions); \
440 rm -f $@; \
441 $(AR) cDPrsT $@ $(filter %.o,$^)
442else
443quiet_cmd_link_multi-m = LD [M] $@
444 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
445endif
446
447$(multi-obj-m): FORCE
448 $(call if_changed,link_multi-m)
449$(call multi_depend, $(multi-obj-m), .o, -objs -y -m)
450
451targets += $(multi-obj-m)
452targets := $(filter-out $(PHONY), $(targets))
453
454# Add intermediate targets:
455# When building objects with specific suffix patterns, add intermediate
456# targets that the final targets are derived from.
457intermediate_targets = $(foreach sfx, $(2), \
458 $(patsubst %$(strip $(1)),%$(sfx), \
459 $(filter %$(strip $(1)), $(targets))))
460# %.asn1.o <- %.asn1.[ch] <- %.asn1
461# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
462# %.lex.o <- %.lex.c <- %.l
463# %.tab.o <- %.tab.[ch] <- %.y
464targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
465 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
466 $(call intermediate_targets, .lex.o, .lex.c) \
467 $(call intermediate_targets, .tab.o, .tab.c .tab.h)
468
469# Build
470# ---------------------------------------------------------------------------
471
472ifdef single-build
473
474KBUILD_SINGLE_TARGETS := $(filter $(obj)/%, $(KBUILD_SINGLE_TARGETS))
475
476curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \
477 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x))))
478
479# Handle single targets without any rule: show "Nothing to be done for ..." or
480# "No rule to make target ..." depending on whether the target exists.
481unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \
482 $(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS)))
483
484single-subdirs := $(foreach d, $(subdir-ym), \
485 $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d)))
486
487__build: $(curdir-single) $(single-subdirs)
488ifneq ($(unknown-single),)
489 $(Q)$(MAKE) -f /dev/null $(unknown-single)
490endif
491 @:
492
493ifeq ($(curdir-single),)
494# Nothing to do in this directory. Do not include any .*.cmd file for speed-up
495targets :=
496else
497targets += $(curdir-single)
498endif
499
500else
501
502__build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \
503 $(if $(KBUILD_MODULES), $(targets-for-modules)) \
504 $(subdir-ym) $(always-y)
505 @:
506
507endif
508
509# Descending
510# ---------------------------------------------------------------------------
511
512PHONY += $(subdir-ym)
513$(subdir-ym):
514 $(Q)$(MAKE) $(build)=$@ \
515 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
516 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \
517 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1)
518
519# Add FORCE to the prequisites of a target to force it to be always rebuilt.
520# ---------------------------------------------------------------------------
521
522PHONY += FORCE
523
524FORCE:
525
526# Read all saved command lines and dependencies for the $(targets) we
527# may be building above, using $(if_changed{,_dep}). As an
528# optimization, we don't need to read them if the target does not
529# exist, we will rebuild anyway in that case.
530
531existing-targets := $(wildcard $(sort $(targets)))
532
533-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
534
535# Create directories for object files if they do not exist
536obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets))))
537# If targets exist, their directories apparently exist. Skip mkdir.
538existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
539obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
540ifneq ($(obj-dirs),)
541$(shell mkdir -p $(obj-dirs))
542endif
543
544.PHONY: $(PHONY)