# SPDX-License-Identifier: GPL-2.0# ==========================================================================# Building# ========================================================================== src := $(srcroot)/$(obj) PHONY := $(obj)/$(obj)/: # Init all relevant variables used in kbuild files so# 1) they have correct type# 2) they do not inherit any value from the environmentobj-y :=obj-m :=lib-y :=lib-m :=always-y :=always-m :=targets :=subdir-y :=subdir-m :=asflags-y  :=ccflags-y  :=rustflags-y :=cppflags-y :=ldflags-y  := subdir-asflags-y :=subdir-ccflags-y := # Read auto.conf if it exists, otherwise ignore-include $(objtree)/include/config/auto.conf include $(srctree)/scripts/Kbuild.includeinclude $(srctree)/scripts/Makefile.compilerinclude $(kbuild-file)include $(srctree)/scripts/Makefile.lib # flags that take effect in current and sub directoriesKBUILD_AFLAGS += $(subdir-asflags-y)KBUILD_CFLAGS += $(subdir-ccflags-y)KBUILD_RUSTFLAGS += $(subdir-rustflags-y) # Figure out what we need to build from the various variables# =========================================================================== # When an object is listed to be built compiled-in and modular,# only build the compiled-in versionobj-m := $(filter-out $(obj-y),$(obj-m)) # Libraries are always collected in one lib file.# Filter out objects already built-inlib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m))) # Subdirectories we need to descend intosubdir-ym := $(sort $(subdir-y) $(subdir-m) \			$(patsubst %/,%, $(filter %/, $(obj-y) $(obj-m)))) # Handle objects in subdirs:# - If we encounter foo/ in $(obj-y), replace it by foo/built-in.a and#   foo/modules.order# - If we encounter foo/ in $(obj-m), replace it by foo/modules.order## Generate modules.order to determine modorder. Unfortunately, we don't have# information about ordering between -y and -m subdirs. Just put -y's first. ifdef need-modorderobj-m := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m))elseobj-m := $(filter-out %/, $(obj-m))endif ifdef need-builtinobj-y		:= $(patsubst %/, %/built-in.a, $(obj-y))elseobj-y		:= $(filter-out %/, $(obj-y))endif # Expand $(foo-objs) $(foo-y) etc. by replacing their individualssuffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s))))# List composite targets that are constructed by combining other targetsmulti-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $m)))# List primitive targets that are compiled from source filesreal-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $(call suffix-search, $m, $2, $3), $m)) # If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite objectmulti-obj-y := $(call multi-search, $(obj-y), .o, -objs -y)multi-obj-m := $(call multi-search, $(obj-m), .o, -objs -y -m)multi-obj-ym := $(multi-obj-y) $(multi-obj-m) # Replace multi-part objects by their individual parts,# including built-in.a from subdirectoriesreal-obj-y := $(call real-search, $(obj-y), .o, -objs -y)real-obj-m := $(call real-search, $(obj-m), .o, -objs -y -m) always-y += $(always-m) # hostprogs-always-y += foo# ... is a shorthand for# hostprogs += foo# always-y  += foohostprogs += $(hostprogs-always-y) $(hostprogs-always-m)always-y += $(hostprogs-always-y) $(hostprogs-always-m) # userprogs-always-y is likewise.userprogs += $(userprogs-always-y) $(userprogs-always-m)always-y += $(userprogs-always-y) $(userprogs-always-m) # Add subdir path ifneq ($(obj),.)extra-y		:= $(addprefix $(obj)/, $(extra-y))always-y	:= $(addprefix $(obj)/, $(always-y))targets		:= $(addprefix $(obj)/, $(targets))obj-m		:= $(addprefix $(obj)/, $(obj-m))lib-y		:= $(addprefix $(obj)/, $(lib-y))real-obj-y	:= $(addprefix $(obj)/, $(real-obj-y))real-obj-m	:= $(addprefix $(obj)/, $(real-obj-m))multi-obj-m	:= $(addprefix $(obj)/, $(multi-obj-m))subdir-ym	:= $(addprefix $(obj)/, $(subdir-ym))endif ifndef obj$(warning kbuild: Makefile.build is included improperly)endif ifeq ($(need-modorder),)ifneq ($(obj-m),)$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)endifendif # =========================================================================== # subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...)subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y)))subdir-modorder := $(sort $(filter %/modules.order, $(obj-m))) targets-for-builtin := $(extra-y) ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)targets-for-builtin += $(obj)/lib.aendif ifdef need-builtintargets-for-builtin += $(obj)/built-in.aendif targets-for-modules := $(foreach x, o mod, \				$(patsubst %.o, %.$x, $(filter %.o, $(obj-m)))) ifdef need-modordertargets-for-modules += $(obj)/modules.orderendif targets += $(targets-for-builtin) $(targets-for-modules) # Linus' kernel sanity checking toolifeq ($(KBUILD_CHECKSRC),1)  quiet_cmd_checksrc       = CHECK   $<        cmd_checksrc       = $(CHECK) $(CHECKFLAGS) $(c_flags) $<else ifeq ($(KBUILD_CHECKSRC),2)  quiet_cmd_force_checksrc = CHECK   $<        cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<endif ifeq ($(KBUILD_EXTMOD),)ifneq ($(KBUILD_EXTRA_WARN),)  cmd_checkdoc = PYTHONDONTWRITEBYTECODE=1 $(PYTHON3) $(KERNELDOC) -none $(KDOCFLAGS) \        $(if $(findstring 2, $(KBUILD_EXTRA_WARN)), -Wall) \        $<endifendif # Compile C sources (.c)# --------------------------------------------------------------------------- quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@      cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $< $(obj)/%.s: $(obj)/%.c FORCE	$(call if_changed_dep,cc_s_c) quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $< $(obj)/%.i: $(obj)/%.c FORCE	$(call if_changed_dep,cpp_i_c) getexportsymbols = $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/$(1)/p' gendwarfksyms = $(objtree)/scripts/gendwarfksyms/gendwarfksyms	\	$(if $(KBUILD_SYMTYPES), --symtypes $(@:.o=.symtypes))	\	$(if $(KBUILD_GENDWARFKSYMS_STABLE), --stable) genksyms = $(objtree)/scripts/genksyms/genksyms		\	$(if $(KBUILD_SYMTYPES), -T $(@:.o=.symtypes))	\	$(if $(KBUILD_PRESERVE), -p)			\	$(addprefix -r , $(wildcard $(@:.o=.symref))) # These mirror gensymtypes_S and co below, keep them in synch.ifdef CONFIG_GENDWARFKSYMScmd_gensymtypes_c = $(if $(skip_gendwarfksyms),,	\	$(call getexportsymbols,\1) | $(gendwarfksyms) $@)elsecmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms)endif # CONFIG_GENDWARFKSYMS # LLVM assembly# Generate .ll files from .cquiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $< $(obj)/%.ll: $(obj)/%.c FORCE	$(call if_changed_dep,cc_ll_c) # C (.c) files# The C file is compiled and updated dependency information is generated.# (See cmd_cc_o_c + relevant part of rule_cc_o_c) is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y) ifdef CONFIG_MODVERSIONS# When module versioning is enabled the following steps are executed:# o compile a <file>.o from <file>.c# o if <file>.o doesn't contain a __export_symbol_*, i.e. does#   not export symbols, it's done.# o otherwise, we calculate symbol versions using the good old#   genksyms on the preprocessed source and dump them into the .cmd file.# o modpost will extract versions from that file and create *.c files that will#   be compiled and linked to the kernel and/or modules. gen_symversions =								\	if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then		\		$(cmd_gensymtypes_$1) >> $(dot-target).cmd;			\	fi cmd_gen_symversions_c =	$(call gen_symversions,c) endif ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT# compiler will not generate __mcount_loc use recordmcount or recordmcount.plifdef BUILD_C_RECORDMCOUNTifeq ("$(origin RECORDMCOUNT_WARN)", "command line")  RECORDMCOUNT_FLAGS = -wendif# Due to recursion, we must skip empty.o.# The empty.o file is created in the make process in order to determine# the target endianness and word size. It is made before all other C# files, including recordmcount.sub_cmd_record_mcount =					\	if [ $(@) != "scripts/mod/empty.o" ]; then	\		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\	fi;recordmcount_source := $(srctree)/scripts/recordmcount.c \		    $(srctree)/scripts/recordmcount.helsesub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \	"$(if $(CONFIG_64BIT),64,32)" \	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \	"$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \	"$(if $(part-of-module),1,0)" "$(@)";recordmcount_source := $(srctree)/scripts/recordmcount.plendif # BUILD_C_RECORDMCOUNTcmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),	\	$(sub_cmd_record_mcount))endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),$(is-kernel-object)) ifdef CONFIG_OBJTOOL$(obj)/%.o: private objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))endif ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi)))endif # Built-in and composite module parts$(obj)/%.o: $(obj)/%.c $(recordmcount_source) FORCE	$(call if_changed_rule,cc_o_c)	$(call cmd,force_checksrc) # To make this rule robust against "Argument list too long" error,# ensure to add $(obj)/ prefix by a shell command.cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \	$(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ $(obj)/%.mod: FORCE	$(call if_changed,mod) quiet_cmd_cc_lst_c = MKLST   $@      cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \		     $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \				     System.map $(OBJDUMP) > $@ $(obj)/%.lst: $(obj)/%.c FORCE	$(call if_changed_dep,cc_lst_c) # Compile Rust sources (.rs)# --------------------------------------------------------------------------- # The features in this list are the ones allowed for non-`rust/` code.##   - Stable since Rust 1.81.0: `feature(lint_reasons)`.#   - Stable since Rust 1.82.0: `feature(asm_const)`,#     `feature(offset_of_nested)`, `feature(raw_ref_op)`.#   - Stable since Rust 1.87.0: `feature(asm_goto)`.#   - Expected to become stable: `feature(arbitrary_self_types)`.#   - To be determined: `feature(used_with_arg)`.## Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on# the unstable features in use.rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,offset_of_nested,raw_ref_op,used_with_arg # `--out-dir` is required to avoid temporaries being created by `rustc` in the# current working directory, which may be not accessible in the out-of-tree# modules case.rust_common_cmd = \	OBJTREE=$(abspath $(objtree)) \	RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \	-Zallow-features=$(rust_allowed_features) \	-Zcrate-attr=no_std \	-Zcrate-attr='feature($(rust_allowed_features))' \	-Zunstable-options --extern pin_init --extern kernel \	--crate-type rlib -L $(objtree)/rust/ \	--crate-name $(basename $(notdir $@)) \	--sysroot=/dev/null \	--out-dir $(dir $@) --emit=dep-info=$(depfile) # `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit# will be used. We explicitly request `-Ccodegen-units=1` in any case, and# the compiler shows a warning if it is not 1. However, if we ever stop# requesting it explicitly and we start using some other `--emit` that does not# imply it (and for which codegen is performed), then we would be out of sync,# i.e. the outputs we would get for the different single targets (e.g. `.ll`)# would not match each other. quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@      cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< $(cmd_objtool) define rule_rustc_o_rs	$(call cmd_and_fixdep,rustc_o_rs)	$(call cmd,gen_objtooldep)endef $(obj)/%.o: $(obj)/%.rs FORCE	+$(call if_changed_rule,rustc_o_rs) quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@      cmd_rustc_rsi_rs = \	$(rust_common_cmd) -Zunpretty=expanded $< >$@; \	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) --config-path $(srctree)/.rustfmt.toml $@ $(obj)/%.rsi: $(obj)/%.rs FORCE	+$(call if_changed_dep,rustc_rsi_rs) quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@      cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $< $(obj)/%.s: $(obj)/%.rs FORCE	+$(call if_changed_dep,rustc_s_rs) quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@      cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $< $(obj)/%.ll: $(obj)/%.rs FORCE	+$(call if_changed_dep,rustc_ll_rs) quiet_cmd_rustc_rs_rs_S = RSCPP $(quiet_modtag) $@      cmd_rustc_rs_rs_S = $(CPP) $(c_flags) -xc -C -P $< | sed '1,/^\/\/ Cut here.$$/d' >$@ $(obj)/%.rs: $(obj)/%.rs.S FORCE	+$(call if_changed_dep,rustc_rs_rs_S) # Compile assembler sources (.S)# --------------------------------------------------------------------------- # .S file exports must have their C prototypes defined in asm/asm-prototypes.h# or a file that it includes, in order to get versioned symbols. We build a# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from# the .S file (with trailing ';'), and run genksyms on that, to extract vers.## This is convoluted. The .S file must first be preprocessed to run guards and# expand names, then the resulting exports must be constructed into plain# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed# to make the genksyms input or compiled into an object for gendwarfksyms.## These mirror gensymtypes_c and co above, keep them in synch.getasmexports =								\   { echo "\#include <linux/kernel.h>" ;				\     echo "\#include <linux/string.h>" ;				\     echo "\#include <asm/asm-prototypes.h>" ;				\     $(call getexportsymbols,EXPORT_SYMBOL(\1);) ; } ifdef CONFIG_GENDWARFKSYMScmd_gensymtypes_S =							\	$(getasmexports) |						\	$(CC) $(c_flags) -c -o $(@:.o=.gendwarfksyms.o) -xc -;		\	$(call getexportsymbols,\1) |					\	$(gendwarfksyms) $(@:.o=.gendwarfksyms.o)elsecmd_gensymtypes_S =							\	$(getasmexports) |						\	$(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms)endif # CONFIG_GENDWARFKSYMS quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $< $(obj)/%.s: $(obj)/%.S FORCE	$(call if_changed_dep,cpp_s_S) ifdef CONFIG_ASM_MODVERSIONS # versioning matches the C process described above, with difference that# we parse asm-prototypes.h C header to get function definitions. cmd_gen_symversions_S = $(call gen_symversions,S) endif $(obj)/%.o: $(obj)/%.S FORCE	$(call if_changed_rule,as_o_S) targets += $(filter-out $(subdir-builtin), $(real-obj-y))targets += $(filter-out $(subdir-modorder), $(real-obj-m))targets += $(lib-y) $(always-y) # Linker scripts preprocessor (.lds.S -> .lds)# ---------------------------------------------------------------------------quiet_cmd_cpp_lds_S = LDS     $@      cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \	                     -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $< $(obj)/%.lds: $(src)/%.lds.S FORCE	$(call if_changed_dep,cpp_lds_S) # ASN.1 grammar# ---------------------------------------------------------------------------quiet_cmd_asn1_compiler = ASN.1   $(basename $@).[ch]      cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \				$(basename $@).c $(basename $@).h $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler	$(call cmd,asn1_compiler) # Build the compiled-in targets# --------------------------------------------------------------------------- # To build objects in subdirs, we need to descend into the directories$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; ## Rule to compile a set of .o files into one .a file (without symbol table)## To make this rule robust against "Argument list too long" error,# remove $(obj)/ prefix, and restore it by a shell command. quiet_cmd_ar_builtin = AR      $@      cmd_ar_builtin = rm -f $@; \	$(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \	$(AR) cDPrST $@ $(obj)/built-in.a: $(real-obj-y) FORCE	$(call if_changed,ar_builtin) # This is a list of build artifacts from the current Makefile and its# sub-directories. The timestamp should be updated when any of the member files. cmd_gen_order = { $(foreach m, $(real-prereqs), \	$(if $(filter %/$(notdir $@), $m), cat $m, echo $m);) :; } \	> $@ $(obj)/modules.order: $(obj-m) FORCE	$(call if_changed,gen_order) ## Rule to compile a set of .o files into one .a file (with symbol table)# $(obj)/lib.a: $(lib-y) FORCE	$(call if_changed,ar) quiet_cmd_ld_multi_m = LD [M]  $@      cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$< $(cmd_objtool) define rule_ld_multi_m	$(call cmd_and_savecmd,ld_multi_m)	$(call cmd,gen_objtooldep)endef

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