xref: /openbmc/linux/scripts/Makefile.build (revision afb46f79) 
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 += $(call cc-option, -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
74# Clang
75warning-1 += $(call cc-disable-warning, initializer-overrides)
76warning-1 += $(call cc-disable-warning, unused-value)
77warning-1 += $(call cc-disable-warning, format)
78warning-1 += $(call cc-disable-warning, unknown-warning-option)
79warning-1 += $(call cc-disable-warning, sign-compare)
80warning-1 += $(call cc-disable-warning, format-zero-length)
81warning-1 += $(call cc-disable-warning, uninitialized)
82warning-1 += $(call cc-option, -fcatch-undefined-behavior)
83
84warning-2 := -Waggregate-return
85warning-2 += -Wcast-align
86warning-2 += -Wdisabled-optimization
87warning-2 += -Wnested-externs
88warning-2 += -Wshadow
89warning-2 += $(call cc-option, -Wlogical-op)
90warning-2 += $(call cc-option, -Wmissing-field-initializers)
91
92warning-3 := -Wbad-function-cast
93warning-3 += -Wcast-qual
94warning-3 += -Wconversion
95warning-3 += -Wpacked
96warning-3 += -Wpadded
97warning-3 += -Wpointer-arith
98warning-3 += -Wredundant-decls
99warning-3 += -Wswitch-default
100warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
101warning-3 += $(call cc-option, -Wvla)
102
103warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
104warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
105warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
106
107ifeq ("$(strip $(warning))","")
108        $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
109endif
110
111KBUILD_CFLAGS += $(warning)
112endif
113
114include scripts/Makefile.lib
115
116ifdef host-progs
117ifneq ($(hostprogs-y),$(host-progs))
118$(warning kbuild: $(obj)/Makefile - Usage of host-progs is deprecated. Please replace with hostprogs-y!)
119hostprogs-y += $(host-progs)
120endif
121endif
122
123# Do not include host rules unless needed
124ifneq ($(hostprogs-y)$(hostprogs-m),)
125include scripts/Makefile.host
126endif
127
128ifneq ($(KBUILD_SRC),)
129# Create output directory if not already present
130_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
131
132# Create directories for object files if directory does not exist
133# Needed when obj-y := dir/file.o syntax is used
134_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
135endif
136
137ifndef obj
138$(warning kbuild: Makefile.build is included improperly)
139endif
140
141# ===========================================================================
142
143ifneq ($(strip $(lib-y) $(lib-m) $(lib-n) $(lib-)),)
144lib-target := $(obj)/lib.a
145endif
146
147ifneq ($(strip $(obj-y) $(obj-m) $(obj-n) $(obj-) $(subdir-m) $(lib-target)),)
148builtin-target := $(obj)/built-in.o
149endif
150
151modorder-target := $(obj)/modules.order
152
153# We keep a list of all modules in $(MODVERDIR)
154
155__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
156	 $(if $(KBUILD_MODULES),$(obj-m) $(modorder-target)) \
157	 $(subdir-ym) $(always)
158	@:
159
160# Linus' kernel sanity checking tool
161ifneq ($(KBUILD_CHECKSRC),0)
162  ifeq ($(KBUILD_CHECKSRC),2)
163    quiet_cmd_force_checksrc = CHECK   $<
164          cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
165  else
166      quiet_cmd_checksrc     = CHECK   $<
167            cmd_checksrc     = $(CHECK) $(CHECKFLAGS) $(c_flags) $< ;
168  endif
169endif
170
171# Do section mismatch analysis for each module/built-in.o
172ifdef CONFIG_DEBUG_SECTION_MISMATCH
173  cmd_secanalysis = ; scripts/mod/modpost $@
174endif
175
176# Compile C sources (.c)
177# ---------------------------------------------------------------------------
178
179# Default is built-in, unless we know otherwise
180modkern_cflags =                                          \
181	$(if $(part-of-module),                           \
182		$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
183		$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
184quiet_modtag := $(empty)   $(empty)
185
186$(real-objs-m)        : part-of-module := y
187$(real-objs-m:.o=.i)  : part-of-module := y
188$(real-objs-m:.o=.s)  : part-of-module := y
189$(real-objs-m:.o=.lst): part-of-module := y
190
191$(real-objs-m)        : quiet_modtag := [M]
192$(real-objs-m:.o=.i)  : quiet_modtag := [M]
193$(real-objs-m:.o=.s)  : quiet_modtag := [M]
194$(real-objs-m:.o=.lst): quiet_modtag := [M]
195
196$(obj-m)              : quiet_modtag := [M]
197
198# Default for not multi-part modules
199modname = $(basetarget)
200
201$(multi-objs-m)         : modname = $(modname-multi)
202$(multi-objs-m:.o=.i)   : modname = $(modname-multi)
203$(multi-objs-m:.o=.s)   : modname = $(modname-multi)
204$(multi-objs-m:.o=.lst) : modname = $(modname-multi)
205$(multi-objs-y)         : modname = $(modname-multi)
206$(multi-objs-y:.o=.i)   : modname = $(modname-multi)
207$(multi-objs-y:.o=.s)   : modname = $(modname-multi)
208$(multi-objs-y:.o=.lst) : modname = $(modname-multi)
209
210quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
211cmd_cc_s_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
212
213$(obj)/%.s: $(src)/%.c FORCE
214	$(call if_changed_dep,cc_s_c)
215
216quiet_cmd_cc_i_c = CPP $(quiet_modtag) $@
217cmd_cc_i_c       = $(CPP) $(c_flags)   -o $@ $<
218
219$(obj)/%.i: $(src)/%.c FORCE
220	$(call if_changed_dep,cc_i_c)
221
222cmd_gensymtypes =                                                           \
223    $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
224    $(GENKSYMS) $(if $(1), -T $(2))                                         \
225     $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX))             \
226     $(if $(KBUILD_PRESERVE),-p)                                            \
227     -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
228
229quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
230cmd_cc_symtypes_c =                                                         \
231    set -e;                                                                 \
232    $(call cmd_gensymtypes,true,$@) >/dev/null;                             \
233    test -s $@ || rm -f $@
234
235$(obj)/%.symtypes : $(src)/%.c FORCE
236	$(call cmd,cc_symtypes_c)
237
238# C (.c) files
239# The C file is compiled and updated dependency information is generated.
240# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
241
242quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
243
244ifndef CONFIG_MODVERSIONS
245cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
246
247else
248# When module versioning is enabled the following steps are executed:
249# o compile a .tmp_<file>.o from <file>.c
250# o if .tmp_<file>.o doesn't contain a __ksymtab version, i.e. does
251#   not export symbols, we just rename .tmp_<file>.o to <file>.o and
252#   are done.
253# o otherwise, we calculate symbol versions using the good old
254#   genksyms on the preprocessed source and postprocess them in a way
255#   that they are usable as a linker script
256# o generate <file>.o from .tmp_<file>.o using the linker to
257#   replace the unresolved symbols __crc_exported_symbol with
258#   the actual value of the checksum generated by genksyms
259
260cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
261cmd_modversions =								\
262	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
263		$(call cmd_gensymtypes,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
264		    > $(@D)/.tmp_$(@F:.o=.ver);					\
265										\
266		$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) 			\
267			-T $(@D)/.tmp_$(@F:.o=.ver);				\
268		rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver);		\
269	else									\
270		mv -f $(@D)/.tmp_$(@F) $@;					\
271	fi;
272endif
273
274ifdef CONFIG_FTRACE_MCOUNT_RECORD
275ifdef BUILD_C_RECORDMCOUNT
276ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
277  RECORDMCOUNT_FLAGS = -w
278endif
279# Due to recursion, we must skip empty.o.
280# The empty.o file is created in the make process in order to determine
281#  the target endianness and word size. It is made before all other C
282#  files, including recordmcount.
283sub_cmd_record_mcount =					\
284	if [ $(@) != "scripts/mod/empty.o" ]; then	\
285		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\
286	fi;
287recordmcount_source := $(srctree)/scripts/recordmcount.c \
288		    $(srctree)/scripts/recordmcount.h
289else
290sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
291	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
292	"$(if $(CONFIG_64BIT),64,32)" \
293	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
294	"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
295	"$(if $(part-of-module),1,0)" "$(@)";
296recordmcount_source := $(srctree)/scripts/recordmcount.pl
297endif
298cmd_record_mcount = 						\
299	if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then	\
300		$(sub_cmd_record_mcount)			\
301	fi;
302endif
303
304define rule_cc_o_c
305	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
306	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \
307	$(cmd_modversions)						  \
308	$(call echo-cmd,record_mcount)					  \
309	$(cmd_record_mcount)						  \
310	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
311	                                              $(dot-target).tmp;  \
312	rm -f $(depfile);						  \
313	mv -f $(dot-target).tmp $(dot-target).cmd
314endef
315
316# Built-in and composite module parts
317$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
318	$(call cmd,force_checksrc)
319	$(call if_changed_rule,cc_o_c)
320
321# Single-part modules are special since we need to mark them in $(MODVERDIR)
322
323$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
324	$(call cmd,force_checksrc)
325	$(call if_changed_rule,cc_o_c)
326	@{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod)
327
328quiet_cmd_cc_lst_c = MKLST   $@
329      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
330		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
331				     System.map $(OBJDUMP) > $@
332
333$(obj)/%.lst: $(src)/%.c FORCE
334	$(call if_changed_dep,cc_lst_c)
335
336# Compile assembler sources (.S)
337# ---------------------------------------------------------------------------
338
339modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
340
341$(real-objs-m)      : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
342$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
343
344quiet_cmd_as_s_S = CPP $(quiet_modtag) $@
345cmd_as_s_S       = $(CPP) $(a_flags)   -o $@ $<
346
347$(obj)/%.s: $(src)/%.S FORCE
348	$(call if_changed_dep,as_s_S)
349
350quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
351cmd_as_o_S       = $(CC) $(a_flags) -c -o $@ $<
352
353$(obj)/%.o: $(src)/%.S FORCE
354	$(call if_changed_dep,as_o_S)
355
356targets += $(real-objs-y) $(real-objs-m) $(lib-y)
357targets += $(extra-y) $(MAKECMDGOALS) $(always)
358
359# Linker scripts preprocessor (.lds.S -> .lds)
360# ---------------------------------------------------------------------------
361quiet_cmd_cpp_lds_S = LDS     $@
362      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -C -U$(ARCH) \
363	                     -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
364
365$(obj)/%.lds: $(src)/%.lds.S FORCE
366	$(call if_changed_dep,cpp_lds_S)
367
368# ASN.1 grammar
369# ---------------------------------------------------------------------------
370quiet_cmd_asn1_compiler = ASN.1   $@
371      cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
372				$(subst .h,.c,$@) $(subst .c,.h,$@)
373
374.PRECIOUS: $(objtree)/$(obj)/%-asn1.c $(objtree)/$(obj)/%-asn1.h
375
376$(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
377	$(call cmd,asn1_compiler)
378
379# Build the compiled-in targets
380# ---------------------------------------------------------------------------
381
382# To build objects in subdirs, we need to descend into the directories
383$(sort $(subdir-obj-y)): $(subdir-ym) ;
384
385#
386# Rule to compile a set of .o files into one .o file
387#
388ifdef builtin-target
389quiet_cmd_link_o_target = LD      $@
390# If the list of objects to link is empty, just create an empty built-in.o
391cmd_link_o_target = $(if $(strip $(obj-y)),\
392		      $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \
393		      $(cmd_secanalysis),\
394		      rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@)
395
396$(builtin-target): $(obj-y) FORCE
397	$(call if_changed,link_o_target)
398
399targets += $(builtin-target)
400endif # builtin-target
401
402#
403# Rule to create modules.order file
404#
405# Create commands to either record .ko file or cat modules.order from
406# a subdirectory
407modorder-cmds =						\
408	$(foreach m, $(modorder),			\
409		$(if $(filter %/modules.order, $m),	\
410			cat $m;, echo kernel/$m;))
411
412$(modorder-target): $(subdir-ym) FORCE
413	$(Q)(cat /dev/null; $(modorder-cmds)) > $@
414
415#
416# Rule to compile a set of .o files into one .a file
417#
418ifdef lib-target
419quiet_cmd_link_l_target = AR      $@
420cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
421
422$(lib-target): $(lib-y) FORCE
423	$(call if_changed,link_l_target)
424
425targets += $(lib-target)
426endif
427
428#
429# Rule to link composite objects
430#
431#  Composite objects are specified in kbuild makefile as follows:
432#    <composite-object>-objs := <list of .o files>
433#  or
434#    <composite-object>-y    := <list of .o files>
435link_multi_deps =                     \
436$(filter $(addprefix $(obj)/,         \
437$($(subst $(obj)/,,$(@:.o=-objs)))    \
438$($(subst $(obj)/,,$(@:.o=-y)))), $^)
439
440quiet_cmd_link_multi-y = LD      $@
441cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
442
443quiet_cmd_link_multi-m = LD [M]  $@
444cmd_link_multi-m = $(cmd_link_multi-y)
445
446# We would rather have a list of rules like
447# 	foo.o: $(foo-objs)
448# but that's not so easy, so we rather make all composite objects depend
449# on the set of all their parts
450$(multi-used-y) : %.o: $(multi-objs-y) FORCE
451	$(call if_changed,link_multi-y)
452
453$(multi-used-m) : %.o: $(multi-objs-m) FORCE
454	$(call if_changed,link_multi-m)
455	@{ echo $(@:.o=.ko); echo $(link_multi_deps); } > $(MODVERDIR)/$(@F:.o=.mod)
456
457targets += $(multi-used-y) $(multi-used-m)
458
459
460# Descending
461# ---------------------------------------------------------------------------
462
463PHONY += $(subdir-ym)
464$(subdir-ym):
465	$(Q)$(MAKE) $(build)=$@
466
467# Add FORCE to the prequisites of a target to force it to be always rebuilt.
468# ---------------------------------------------------------------------------
469
470PHONY += FORCE
471
472FORCE:
473
474# Read all saved command lines and dependencies for the $(targets) we
475# may be building above, using $(if_changed{,_dep}). As an
476# optimization, we don't need to read them if the target does not
477# exist, we will rebuild anyway in that case.
478
479targets := $(wildcard $(sort $(targets)))
480cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
481
482ifneq ($(cmd_files),)
483  include $(cmd_files)
484endif
485
486# Declare the contents of the .PHONY variable as phony.  We keep that
487# information in a variable se we can use it in if_changed and friends.
488
489.PHONY: $(PHONY)
490