Root/scripts/Makefile.build

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)) \
215     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
216     $(if $(KBUILD_PRESERVE),-p) \
217     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
218
219quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
220cmd_cc_symtypes_c = \
221    set -e; \
222    $(call cmd_gensymtypes,true,$@) >/dev/null; \
223    test -s $@ || rm -f $@
224
225$(obj)/%.symtypes : $(src)/%.c FORCE
226    $(call cmd,cc_symtypes_c)
227
228# C (.c) files
229# The C file is compiled and updated dependency information is generated.
230# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
231
232quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
233
234ifndef CONFIG_MODVERSIONS
235cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
236
237else
238# When module versioning is enabled the following steps are executed:
239# o compile a .tmp_<file>.o from <file>.c
240# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
241# not export symbols, we just rename .tmp_<file>.o to <file>.o and
242# are done.
243# o otherwise, we calculate symbol versions using the good old
244# genksyms on the preprocessed source and postprocess them in a way
245# that they are usable as a linker script
246# o generate <file>.o from .tmp_<file>.o using the linker to
247# replace the unresolved symbols __crc_exported_symbol with
248# the actual value of the checksum generated by genksyms
249
250cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
251cmd_modversions = \
252    if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
253        $(call cmd_gensymtypes,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
254            > $(@D)/.tmp_$(@F:.o=.ver); \
255                                        \
256        $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
257            -T $(@D)/.tmp_$(@F:.o=.ver); \
258        rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
259    else \
260        mv -f $(@D)/.tmp_$(@F) $@; \
261    fi;
262endif
263
264ifdef CONFIG_FTRACE_MCOUNT_RECORD
265ifdef BUILD_C_RECORDMCOUNT
266ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
267  RECORDMCOUNT_FLAGS = -w
268endif
269# Due to recursion, we must skip empty.o.
270# The empty.o file is created in the make process in order to determine
271# the target endianness and word size. It is made before all other C
272# files, including recordmcount.
273sub_cmd_record_mcount = \
274    if [ $(@) != "scripts/mod/empty.o" ]; then \
275        $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
276    fi;
277recordmcount_source := $(srctree)/scripts/recordmcount.c \
278            $(srctree)/scripts/recordmcount.h
279else
280sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
281    "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
282    "$(if $(CONFIG_64BIT),64,32)" \
283    "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
284    "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
285    "$(if $(part-of-module),1,0)" "$(@)";
286recordmcount_source := $(srctree)/scripts/recordmcount.pl
287endif
288cmd_record_mcount = \
289    if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then \
290        $(sub_cmd_record_mcount) \
291    fi;
292endif
293
294define rule_cc_o_c
295    $(call echo-cmd,checksrc) $(cmd_checksrc) \
296    $(call echo-cmd,cc_o_c) $(cmd_cc_o_c); \
297    $(cmd_modversions) \
298    $(call echo-cmd,record_mcount) \
299    $(cmd_record_mcount) \
300    scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > \
301                                                  $(dot-target).tmp; \
302    rm -f $(depfile); \
303    mv -f $(dot-target).tmp $(dot-target).cmd
304endef
305
306# Built-in and composite module parts
307$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
308    $(call cmd,force_checksrc)
309    $(call if_changed_rule,cc_o_c)
310
311# Single-part modules are special since we need to mark them in $(MODVERDIR)
312
313$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
314    $(call cmd,force_checksrc)
315    $(call if_changed_rule,cc_o_c)
316    @{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod)
317
318quiet_cmd_cc_lst_c = MKLST $@
319      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
320             $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
321                     System.map $(OBJDUMP) > $@
322
323$(obj)/%.lst: $(src)/%.c FORCE
324    $(call if_changed_dep,cc_lst_c)
325
326# Compile assembler sources (.S)
327# ---------------------------------------------------------------------------
328
329modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
330
331$(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
332$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
333
334quiet_cmd_as_s_S = CPP $(quiet_modtag) $@
335cmd_as_s_S = $(CPP) $(a_flags) -o $@ $<
336
337$(obj)/%.s: $(src)/%.S FORCE
338    $(call if_changed_dep,as_s_S)
339
340quiet_cmd_as_o_S = AS $(quiet_modtag) $@
341cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
342
343$(obj)/%.o: $(src)/%.S FORCE
344    $(call if_changed_dep,as_o_S)
345
346targets += $(real-objs-y) $(real-objs-m) $(lib-y)
347targets += $(extra-y) $(MAKECMDGOALS) $(always)
348
349# Linker scripts preprocessor (.lds.S -> .lds)
350# ---------------------------------------------------------------------------
351quiet_cmd_cpp_lds_S = LDS $@
352      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
353                         -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
354
355$(obj)/%.lds: $(src)/%.lds.S FORCE
356    $(call if_changed_dep,cpp_lds_S)
357
358# ASN.1 grammar
359# ---------------------------------------------------------------------------
360quiet_cmd_asn1_compiler = ASN.1 $@
361      cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
362                $(subst .h,.c,$@) $(subst .c,.h,$@)
363
364.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
365
366$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
367    $(call cmd,asn1_compiler)
368
369# Build the compiled-in targets
370# ---------------------------------------------------------------------------
371
372# To build objects in subdirs, we need to descend into the directories
373$(sort $(subdir-obj-y)): $(subdir-ym) ;
374
375#
376# Rule to compile a set of .o files into one .o file
377#
378ifdef builtin-target
379quiet_cmd_link_o_target = LD $@
380# If the list of objects to link is empty, just create an empty built-in.o
381cmd_link_o_target = $(if $(strip $(obj-y)),\
382              $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \
383              $(cmd_secanalysis),\
384              rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@)
385
386$(builtin-target): $(obj-y) FORCE
387    $(call if_changed,link_o_target)
388
389targets += $(builtin-target)
390endif # builtin-target
391
392#
393# Rule to create modules.order file
394#
395# Create commands to either record .ko file or cat modules.order from
396# a subdirectory
397modorder-cmds = \
398    $(foreach m, $(modorder), \
399        $(if $(filter %/modules.order, $m), \
400            cat $m;, echo kernel/$m;))
401
402$(modorder-target): $(subdir-ym) FORCE
403    $(Q)(cat /dev/null; $(modorder-cmds)) > $@
404
405#
406# Rule to compile a set of .o files into one .a file
407#
408ifdef lib-target
409quiet_cmd_link_l_target = AR $@
410cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
411
412$(lib-target): $(lib-y) FORCE
413    $(call if_changed,link_l_target)
414
415targets += $(lib-target)
416endif
417
418#
419# Rule to link composite objects
420#
421# Composite objects are specified in kbuild makefile as follows:
422# <composite-object>-objs := <list of .o files>
423# or
424# <composite-object>-y := <list of .o files>
425link_multi_deps = \
426$(filter $(addprefix $(obj)/, \
427$($(subst $(obj)/,,$(@:.o=-objs))) \
428$($(subst $(obj)/,,$(@:.o=-y)))), $^)
429 
430quiet_cmd_link_multi-y = LD $@
431cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
432
433quiet_cmd_link_multi-m = LD [M] $@
434cmd_link_multi-m = $(cmd_link_multi-y)
435
436# We would rather have a list of rules like
437# foo.o: $(foo-objs)
438# but that's not so easy, so we rather make all composite objects depend
439# on the set of all their parts
440$(multi-used-y) : %.o: $(multi-objs-y) FORCE
441    $(call if_changed,link_multi-y)
442
443$(multi-used-m) : %.o: $(multi-objs-m) FORCE
444    $(call if_changed,link_multi-m)
445    @{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod)
446
447targets += $(multi-used-y) $(multi-used-m)
448
449
450# Descending
451# ---------------------------------------------------------------------------
452
453PHONY += $(subdir-ym)
454$(subdir-ym):
455    $(Q)$(MAKE) $(build)=$@
456
457# Add FORCE to the prequisites of a target to force it to be always rebuilt.
458# ---------------------------------------------------------------------------
459
460PHONY += FORCE
461
462FORCE:
463
464# Read all saved command lines and dependencies for the $(targets) we
465# may be building above, using $(if_changed{,_dep}). As an
466# optimization, we don't need to read them if the target does not
467# exist, we will rebuild anyway in that case.
468
469targets := $(wildcard $(sort $(targets)))
470cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
471
472ifneq ($(cmd_files),)
473  include $(cmd_files)
474endif
475
476# Declare the contents of the .PHONY variable as phony. We keep that
477# information in a variable se we can use it in if_changed and friends.
478
479.PHONY: $(PHONY)
480

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