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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# ==========================================================================
2# Building
3# ==========================================================================
4
5src := $(obj)
6
7PHONY := __build
8__build:
9
10# Init all relevant variables used in kbuild files so
11# 1) they have correct type
12# 2) they do not inherit any value from the environment
13obj-y :=
14obj-m :=
15lib-y :=
16lib-m :=
17always :=
18targets :=
19subdir-y :=
20subdir-m :=
21EXTRA_AFLAGS :=
22EXTRA_CFLAGS :=
23EXTRA_CPPFLAGS :=
24EXTRA_LDFLAGS :=
25asflags-y :=
26ccflags-y :=
27cppflags-y :=
28ldflags-y :=
29
30subdir-asflags-y :=
31subdir-ccflags-y :=
32
33# Read auto.conf if it exists, otherwise ignore
34-include include/config/auto.conf
35
36include scripts/Kbuild.include
37
38# For backward compatibility check that these variables do not change
39save-cflags := $(CFLAGS)
40
41# The filename Kbuild has precedence over Makefile
42kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
43kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
44include $(kbuild-file)
45
46# If the save-* variables changed error out
47ifeq ($(KBUILD_NOPEDANTIC),)
48 ifneq ("$(save-cflags)","$(CFLAGS)")
49 $(error CFLAGS was changed in "$(kbuild-file)". Fix it to use ccflags-y)
50 endif
51endif
52
53#
54# make W=... settings
55#
56# W=1 - warnings that may be relevant and does not occur too often
57# W=2 - warnings that occur quite often but may still be relevant
58# W=3 - the more obscure warnings, can most likely be ignored
59#
60# $(call cc-option, -W...) handles gcc -W.. options which
61# are not supported by all versions of the compiler
62ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS
63warning- := $(empty)
64
65warning-1 := -Wextra -Wunused -Wno-unused-parameter
66warning-1 += -Wmissing-declarations
67warning-1 += -Wmissing-format-attribute
68warning-1 += -Wmissing-prototypes
69warning-1 += -Wold-style-definition
70warning-1 += $(call cc-option, -Wmissing-include-dirs)
71warning-1 += $(call cc-option, -Wunused-but-set-variable)
72warning-1 += $(call cc-disable-warning, missing-field-initializers)
73
74warning-2 := -Waggregate-return
75warning-2 += -Wcast-align
76warning-2 += -Wdisabled-optimization
77warning-2 += -Wnested-externs
78warning-2 += -Wshadow
79warning-2 += $(call cc-option, -Wlogical-op)
80warning-2 += $(call cc-option, -Wmissing-field-initializers)
81
82warning-3 := -Wbad-function-cast
83warning-3 += -Wcast-qual
84warning-3 += -Wconversion
85warning-3 += -Wpacked
86warning-3 += -Wpadded
87warning-3 += -Wpointer-arith
88warning-3 += -Wredundant-decls
89warning-3 += -Wswitch-default
90warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
91warning-3 += $(call cc-option, -Wvla)
92
93warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
94warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
95warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
96
97ifeq ("$(strip $(warning))","")
98 $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
99endif
100
101KBUILD_CFLAGS += $(warning)
102endif
103
104include scripts/Makefile.lib
105
106ifdef host-progs
107ifneq ($(hostprogs-y),$(host-progs))
108$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
109hostprogs-y += $(host-progs)
110endif
111endif
112
113# Do not include host rules unless needed
114ifneq ($(hostprogs-y)$(hostprogs-m),)
115include scripts/Makefile.host
116endif
117
118ifneq ($(KBUILD_SRC),)
119# Create output directory if not already present
120_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
121
122# Create directories for object files if directory does not exist
123# Needed when obj-y := dir/file.o syntax is used
124_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
125endif
126
127ifndef obj
128$(warning kbuild: Makefile.build is included improperly)
129endif
130
131# ===========================================================================
132
133ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),)
134lib-target := $(obj)/lib.a
135endif
136
137ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(subdir-m) $(lib-target)),)
138builtin-target := $(obj)/built-in.o
139endif
140
141modorder-target := $(obj)/modules.order
142
143# We keep a list of all modules in $(MODVERDIR)
144
145__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
146 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
147 $(subdir-ym) $(always)
148 @:
149
150# Linus' kernel sanity checking tool
151ifneq ($(KBUILD_CHECKSRC),0)
152 ifeq ($(KBUILD_CHECKSRC),2)
153 quiet_cmd_force_checksrc = CHECK $<
154 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
155 else
156 quiet_cmd_checksrc = CHECK $<
157 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
158 endif
159endif
160
161# Do section mismatch analysis for each module/built-in.o
162ifdef CONFIG_DEBUG_SECTION_MISMATCH
163 cmd_secanalysis = ; scripts/mod/modpost $@
164endif
165
166# Compile C sources (.c)
167# ---------------------------------------------------------------------------
168
169# Default is built-in, unless we know otherwise
170modkern_cflags = \
171 $(if $(part-of-module), \
172 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
173 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
174quiet_modtag := $(empty) $(empty)
175
176$(real-objs-m) : part-of-module := y
177$(real-objs-m:.o=.i) : part-of-module := y
178$(real-objs-m:.o=.s) : part-of-module := y
179$(real-objs-m:.o=.lst): part-of-module := y
180
181$(real-objs-m) : quiet_modtag := [M]
182$(real-objs-m:.o=.i) : quiet_modtag := [M]
183$(real-objs-m:.o=.s) : quiet_modtag := [M]
184$(real-objs-m:.o=.lst): quiet_modtag := [M]
185
186$(obj-m) : quiet_modtag := [M]
187
188# Default for not multi-part modules
189modname = $(basetarget)
190
191$(multi-objs-m) : modname = $(modname-multi)
192$(multi-objs-m:.o=.i) : modname = $(modname-multi)
193$(multi-objs-m:.o=.s) : modname = $(modname-multi)
194$(multi-objs-m:.o=.lst) : modname = $(modname-multi)
195$(multi-objs-y) : modname = $(modname-multi)
196$(multi-objs-y:.o=.i) : modname = $(modname-multi)
197$(multi-objs-y:.o=.s) : modname = $(modname-multi)
198$(multi-objs-y:.o=.lst) : modname = $(modname-multi)
199
200quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
201cmd_cc_s_c = $(CC) $(c_flags) -fverbose-asm -S -o $@ $<
202
203$(obj)/%.s: $(src)/%.c FORCE
204 $(call if_changed_dep,cc_s_c)
205
206quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@
207cmd_cc_i_c = $(CPP) $(c_flags) -o $@ $<
208
209$(obj)/%.i: $(src)/%.c FORCE
210 $(call if_changed_dep,cc_i_c)
211
212cmd_gensymtypes = \
213 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
214 $(GENKSYMS) $(if $(1), -T $(2)) -a $(ARCH) \
215 $(if $(KBUILD_PRESERVE),-p) \
216 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
217
218quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
219cmd_cc_symtypes_c = \
220 set -e; \
221 $(call cmd_gensymtypes,true,$@) >/dev/null; \
222 test -s $@ || rm -f $@
223
224$(obj)/%.symtypes : $(src)/%.c FORCE
225 $(call cmd,cc_symtypes_c)
226
227# C (.c) files
228# The C file is compiled and updated dependency information is generated.
229# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
230
231quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
232
233ifndef CONFIG_MODVERSIONS
234cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
235
236else
237# When module versioning is enabled the following steps are executed:
238# o compile a .tmp_<file>.o from <file>.c
239# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
240# not export symbols, we just rename .tmp_<file>.o to <file>.o and
241# are done.
242# o otherwise, we calculate symbol versions using the good old
243# genksyms on the preprocessed source and postprocess them in a way
244# that they are usable as a linker script
245# o generate <file>.o from .tmp_<file>.o using the linker to
246# replace the unresolved symbols __crc_exported_symbol with
247# the actual value of the checksum generated by genksyms
248
249cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
250cmd_modversions = \
251 if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
252 $(call cmd_gensymtypes,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
253 > $(@D)/.tmp_$(@F:.o=.ver); \
254 \
255 $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
256 -T $(@D)/.tmp_$(@F:.o=.ver); \
257 rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
258 else \
259 mv -f $(@D)/.tmp_$(@F) $@; \
260 fi;
261endif
262
263ifdef CONFIG_FTRACE_MCOUNT_RECORD
264ifdef BUILD_C_RECORDMCOUNT
265ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
266 RECORDMCOUNT_FLAGS = -w
267endif
268# Due to recursion, we must skip empty.o.
269# The empty.o file is created in the make process in order to determine
270# the target endianness and word size. It is made before all other C
271# files, including recordmcount.
272sub_cmd_record_mcount = \
273 if [ $(@) != "scripts/mod/empty.o" ]; then \
274 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
275 fi;
276recordmcount_source := $(srctree)/scripts/recordmcount.c \
277 $(srctree)/scripts/recordmcount.h
278else
279sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
280 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
281 "$(if $(CONFIG_64BIT),64,32)" \
282 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
283 "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
284 "$(if $(part-of-module),1,0)" "$(@)";
285recordmcount_source := $(srctree)/scripts/recordmcount.pl
286endif
287cmd_record_mcount = \
288 if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then \
289 $(sub_cmd_record_mcount) \
290 fi;
291endif
292
293define rule_cc_o_c
294 $(call echo-cmd,checksrc) $(cmd_checksrc) \
295 $(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \
296 $(cmd_modversions) \
297 $(call echo-cmd,record_mcount) \
298 $(cmd_record_mcount) \
299 scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \
300 $(dot-target).tmp; \
301 rm -f $(depfile); \
302 mv -f $(dot-target).tmp $(dot-target).cmd
303endef
304
305# Built-in and composite module parts
306$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
307 $(call cmd,force_checksrc)
308 $(call if_changed_rule,cc_o_c)
309
310# Single-part modules are special since we need to mark them in $(MODVERDIR)
311
312$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
313 $(call cmd,force_checksrc)
314 $(call if_changed_rule,cc_o_c)
315 @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod)
316
317quiet_cmd_cc_lst_c = MKLST $@
318 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
319 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
320 System.map $(OBJDUMP) > $@
321
322$(obj)/%.lst: $(src)/%.c FORCE
323 $(call if_changed_dep,cc_lst_c)
324
325# Compile assembler sources (.S)
326# ---------------------------------------------------------------------------
327
328modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
329
330$(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
331$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
332
333quiet_cmd_as_s_S = CPP $(quiet_modtag) $@
334cmd_as_s_S = $(CPP) $(a_flags) -o $@ $<
335
336$(obj)/%.s: $(src)/%.S FORCE
337 $(call if_changed_dep,as_s_S)
338
339quiet_cmd_as_o_S = AS $(quiet_modtag) $@
340cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
341
342$(obj)/%.o: $(src)/%.S FORCE
343 $(call if_changed_dep,as_o_S)
344
345targets += $(real-objs-y) $(real-objs-m) $(lib-y)
346targets += $(extra-y) $(MAKECMDGOALS) $(always)
347
348# Linker scripts preprocessor (.lds.S -> .lds)
349# ---------------------------------------------------------------------------
350quiet_cmd_cpp_lds_S = LDS $@
351 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
352 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
353
354$(obj)/%.lds: $(src)/%.lds.S FORCE
355 $(call if_changed_dep,cpp_lds_S)
356
357# Build the compiled-in targets
358# ---------------------------------------------------------------------------
359
360# To build objects in subdirs, we need to descend into the directories
361$(sort $(subdir-obj-y)): $(subdir-ym) ;
362
363#
364# Rule to compile a set of .o files into one .o file
365#
366ifdef builtin-target
367quiet_cmd_link_o_target = LD $@
368# If the list of objects to link is empty, just create an empty built-in.o
369cmd_link_o_target = $(if $(strip $(obj-y)),\
370 $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \
371 $(cmd_secanalysis),\
372 rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@)
373
374$(builtin-target): $(obj-y) FORCE
375 $(call if_changed,link_o_target)
376
377targets += $(builtin-target)
378endif # builtin-target
379
380#
381# Rule to create modules.order file
382#
383# Create commands to either record .ko file or cat modules.order from
384# a subdirectory
385modorder-cmds = \
386 $(foreach m, $(modorder), \
387 $(if $(filter %/modules.order, $m), \
388 cat $m;, echo kernel/$m;))
389
390$(modorder-target): $(subdir-ym) FORCE
391 $(Q)(cat /dev/null; $(modorder-cmds)) > $@
392
393#
394# Rule to compile a set of .o files into one .a file
395#
396ifdef lib-target
397quiet_cmd_link_l_target = AR $@
398cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
399
400$(lib-target): $(lib-y) FORCE
401 $(call if_changed,link_l_target)
402
403targets += $(lib-target)
404endif
405
406#
407# Rule to link composite objects
408#
409# Composite objects are specified in kbuild makefile as follows:
410# <composite-object>-objs := <list of .o files>
411# or
412# <composite-object>-y := <list of .o files>
413link_multi_deps = \
414$(filter $(addprefix $(obj)/, \
415$($(subst $(obj)/,,$(@:.o=-objs))) \
416$($(subst $(obj)/,,$(@:.o=-y)))), $^)
417
418quiet_cmd_link_multi-y = LD $@
419cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
420
421quiet_cmd_link_multi-m = LD [M] $@
422cmd_link_multi-m = $(cmd_link_multi-y)
423
424# We would rather have a list of rules like
425# foo.o: $(foo-objs)
426# but that's not so easy, so we rather make all composite objects depend
427# on the set of all their parts
428$(multi-used-y) : %.o: $(multi-objs-y) FORCE
429 $(call if_changed,link_multi-y)
430
431$(multi-used-m) : %.o: $(multi-objs-m) FORCE
432 $(call if_changed,link_multi-m)
433 @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod)
434
435targets += $(multi-used-y) $(multi-used-m)
436
437
438# Descending
439# ---------------------------------------------------------------------------
440
441PHONY += $(subdir-ym)
442$(subdir-ym):
443 $(Q)$(MAKE) $(build)=$@
444
445# Add FORCE to the prequisites of a target to force it to be always rebuilt.
446# ---------------------------------------------------------------------------
447
448PHONY += FORCE
449
450FORCE:
451
452# Read all saved command lines and dependencies for the $(targets) we
453# may be building above, using $(if_changed{,_dep}). As an
454# optimization, we don't need to read them if the target does not
455# exist, we will rebuild anyway in that case.
456
457targets := $(wildcard $(sort $(targets)))
458cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
459
460ifneq ($(cmd_files),)
461 include $(cmd_files)
462endif
463
464# Declare the contents of the .PHONY variable as phony. We keep that
465# information in a variable se we can use it in if_changed and friends.
466
467.PHONY: $(PHONY)