| # SPDX-License-Identifier: GPL-2.0 | 
 | ifneq ($(O),) | 
 | ifeq ($(origin O), command line) | 
 | 	dummy := $(if $(shell test -d $(O) || echo $(O)),$(error O=$(O) does not exist),) | 
 | 	ABSOLUTE_O := $(shell cd $(O) ; pwd) | 
 | 	OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/) | 
 | 	COMMAND_O := O=$(ABSOLUTE_O) | 
 | ifeq ($(objtree),) | 
 | 	objtree := $(O) | 
 | endif | 
 | endif | 
 | endif | 
 |  | 
 | # check that the output directory actually exists | 
 | ifneq ($(OUTPUT),) | 
 | OUTDIR := $(shell cd $(OUTPUT) && pwd) | 
 | $(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist)) | 
 | endif | 
 |  | 
 | # | 
 | # Include saner warnings here, which can catch bugs: | 
 | # | 
 | EXTRA_WARNINGS := -Wbad-function-cast | 
 | EXTRA_WARNINGS += -Wdeclaration-after-statement | 
 | EXTRA_WARNINGS += -Wformat-security | 
 | EXTRA_WARNINGS += -Wformat-y2k | 
 | EXTRA_WARNINGS += -Winit-self | 
 | EXTRA_WARNINGS += -Wmissing-declarations | 
 | EXTRA_WARNINGS += -Wmissing-prototypes | 
 | EXTRA_WARNINGS += -Wnested-externs | 
 | EXTRA_WARNINGS += -Wno-system-headers | 
 | EXTRA_WARNINGS += -Wold-style-definition | 
 | EXTRA_WARNINGS += -Wpacked | 
 | EXTRA_WARNINGS += -Wredundant-decls | 
 | EXTRA_WARNINGS += -Wshadow | 
 | EXTRA_WARNINGS += -Wstrict-prototypes | 
 | EXTRA_WARNINGS += -Wswitch-default | 
 | EXTRA_WARNINGS += -Wswitch-enum | 
 | EXTRA_WARNINGS += -Wundef | 
 | EXTRA_WARNINGS += -Wwrite-strings | 
 | EXTRA_WARNINGS += -Wformat | 
 |  | 
 | CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?) | 
 |  | 
 | # Makefiles suck: This macro sets a default value of $(2) for the | 
 | # variable named by $(1), unless the variable has been set by | 
 | # environment or command line. This is necessary for CC and AR | 
 | # because make sets default values, so the simpler ?= approach | 
 | # won't work as expected. | 
 | define allow-override | 
 |   $(if $(or $(findstring environment,$(origin $(1))),\ | 
 |             $(findstring command line,$(origin $(1)))),,\ | 
 |     $(eval $(1) = $(2))) | 
 | endef | 
 |  | 
 | # Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix. | 
 | $(call allow-override,CC,$(CROSS_COMPILE)gcc) | 
 | $(call allow-override,AR,$(CROSS_COMPILE)ar) | 
 | $(call allow-override,LD,$(CROSS_COMPILE)ld) | 
 | $(call allow-override,CXX,$(CROSS_COMPILE)g++) | 
 | $(call allow-override,STRIP,$(CROSS_COMPILE)strip) | 
 |  | 
 | ifeq ($(CC_NO_CLANG), 1) | 
 | EXTRA_WARNINGS += -Wstrict-aliasing=3 | 
 | endif | 
 |  | 
 | # Hack to avoid type-punned warnings on old systems such as RHEL5: | 
 | # We should be changing CFLAGS and checking gcc version, but this | 
 | # will do for now and keep the above -Wstrict-aliasing=3 in place | 
 | # in newer systems. | 
 | # Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h | 
 | ifneq ($(filter 3.%,$(MAKE_VERSION)),)  # make-3 | 
 | EXTRA_WARNINGS += -fno-strict-aliasing | 
 | endif | 
 |  | 
 | ifneq ($(findstring $(MAKEFLAGS), w),w) | 
 | PRINT_DIR = --no-print-directory | 
 | else | 
 | NO_SUBDIR = : | 
 | endif | 
 |  | 
 | ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),) | 
 |   silent=1 | 
 | endif | 
 |  | 
 | # | 
 | # Define a callable command for descending to a new directory | 
 | # | 
 | # Call by doing: $(call descend,directory[,target]) | 
 | # | 
 | descend = \ | 
 | 	+mkdir -p $(OUTPUT)$(1) && \ | 
 | 	$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2) | 
 |  | 
 | QUIET_SUBDIR0  = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir | 
 | QUIET_SUBDIR1  = | 
 |  | 
 | ifneq ($(silent),1) | 
 |   ifneq ($(V),1) | 
 | 	QUIET_CC       = @echo '  CC       '$@; | 
 | 	QUIET_CC_FPIC  = @echo '  CC FPIC  '$@; | 
 | 	QUIET_AR       = @echo '  AR       '$@; | 
 | 	QUIET_LINK     = @echo '  LINK     '$@; | 
 | 	QUIET_MKDIR    = @echo '  MKDIR    '$@; | 
 | 	QUIET_GEN      = @echo '  GEN      '$@; | 
 | 	QUIET_SUBDIR0  = +@subdir= | 
 | 	QUIET_SUBDIR1  = ;$(NO_SUBDIR) \ | 
 | 			  echo '  SUBDIR   '$$subdir; \ | 
 | 			 $(MAKE) $(PRINT_DIR) -C $$subdir | 
 | 	QUIET_FLEX     = @echo '  FLEX     '$@; | 
 | 	QUIET_BISON    = @echo '  BISON    '$@; | 
 |  | 
 | 	descend = \ | 
 | 		+@echo	       '  DESCEND  '$(1); \ | 
 | 		mkdir -p $(OUTPUT)$(1) && \ | 
 | 		$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2) | 
 |  | 
 | 	QUIET_CLEAN    = @printf '  CLEAN    %s\n' $1; | 
 | 	QUIET_INSTALL  = @printf '  INSTALL  %s\n' $1; | 
 | 	QUIET_UNINST   = @printf '  UNINST   %s\n' $1; | 
 |   endif | 
 | endif | 
 |  | 
 | pound := \# |