1# SPDX-License-Identifier: GPL-2.0 2ifneq ($(O),) 3ifeq ($(origin O), command line) 4 dummy := $(if $(shell test -d $(O) || echo $(O)),$(error O=$(O) does not exist),) 5 ABSOLUTE_O := $(shell cd $(O) ; pwd) 6 OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/) 7 COMMAND_O := O=$(ABSOLUTE_O) 8ifeq ($(objtree),) 9 objtree := $(O) 10endif 11endif 12endif 13 14# check that the output directory actually exists 15ifneq ($(OUTPUT),) 16OUTDIR := $(shell cd $(OUTPUT) && pwd) 17$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist)) 18endif 19 20# 21# Include saner warnings here, which can catch bugs: 22# 23EXTRA_WARNINGS := -Wbad-function-cast 24EXTRA_WARNINGS += -Wdeclaration-after-statement 25EXTRA_WARNINGS += -Wformat-security 26EXTRA_WARNINGS += -Wformat-y2k 27EXTRA_WARNINGS += -Winit-self 28EXTRA_WARNINGS += -Wmissing-declarations 29EXTRA_WARNINGS += -Wmissing-prototypes 30EXTRA_WARNINGS += -Wnested-externs 31EXTRA_WARNINGS += -Wno-system-headers 32EXTRA_WARNINGS += -Wold-style-definition 33EXTRA_WARNINGS += -Wpacked 34EXTRA_WARNINGS += -Wredundant-decls 35EXTRA_WARNINGS += -Wshadow 36EXTRA_WARNINGS += -Wstrict-prototypes 37EXTRA_WARNINGS += -Wswitch-default 38EXTRA_WARNINGS += -Wswitch-enum 39EXTRA_WARNINGS += -Wundef 40EXTRA_WARNINGS += -Wwrite-strings 41EXTRA_WARNINGS += -Wformat 42 43CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?) 44 45# Makefiles suck: This macro sets a default value of $(2) for the 46# variable named by $(1), unless the variable has been set by 47# environment or command line. This is necessary for CC and AR 48# because make sets default values, so the simpler ?= approach 49# won't work as expected. 50define allow-override 51 $(if $(or $(findstring environment,$(origin $(1))),\ 52 $(findstring command line,$(origin $(1)))),,\ 53 $(eval $(1) = $(2))) 54endef 55 56# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix. 57$(call allow-override,CC,$(CROSS_COMPILE)gcc) 58$(call allow-override,AR,$(CROSS_COMPILE)ar) 59$(call allow-override,LD,$(CROSS_COMPILE)ld) 60$(call allow-override,CXX,$(CROSS_COMPILE)g++) 61$(call allow-override,STRIP,$(CROSS_COMPILE)strip) 62 63ifeq ($(CC_NO_CLANG), 1) 64EXTRA_WARNINGS += -Wstrict-aliasing=3 65endif 66 67# Hack to avoid type-punned warnings on old systems such as RHEL5: 68# We should be changing CFLAGS and checking gcc version, but this 69# will do for now and keep the above -Wstrict-aliasing=3 in place 70# in newer systems. 71# Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h 72ifneq ($(filter 3.%,$(MAKE_VERSION)),) # make-3 73EXTRA_WARNINGS += -fno-strict-aliasing 74endif 75 76ifneq ($(findstring $(MAKEFLAGS), w),w) 77PRINT_DIR = --no-print-directory 78else 79NO_SUBDIR = : 80endif 81 82ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),) 83 silent=1 84endif 85 86# 87# Define a callable command for descending to a new directory 88# 89# Call by doing: $(call descend,directory[,target]) 90# 91descend = \ 92 +mkdir -p $(OUTPUT)$(1) && \ 93 $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2) 94 95QUIET_SUBDIR0 = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir 96QUIET_SUBDIR1 = 97 98ifneq ($(silent),1) 99 ifneq ($(V),1) 100 QUIET_CC = @echo ' CC '$@; 101 QUIET_CC_FPIC = @echo ' CC FPIC '$@; 102 QUIET_AR = @echo ' AR '$@; 103 QUIET_LINK = @echo ' LINK '$@; 104 QUIET_MKDIR = @echo ' MKDIR '$@; 105 QUIET_GEN = @echo ' GEN '$@; 106 QUIET_SUBDIR0 = +@subdir= 107 QUIET_SUBDIR1 = ;$(NO_SUBDIR) \ 108 echo ' SUBDIR '$$subdir; \ 109 $(MAKE) $(PRINT_DIR) -C $$subdir 110 QUIET_FLEX = @echo ' FLEX '$@; 111 QUIET_BISON = @echo ' BISON '$@; 112 113 descend = \ 114 +@echo ' DESCEND '$(1); \ 115 mkdir -p $(OUTPUT)$(1) && \ 116 $(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2) 117 118 QUIET_CLEAN = @printf ' CLEAN %s\n' $1; 119 QUIET_INSTALL = @printf ' INSTALL %s\n' $1; 120 QUIET_UNINST = @printf ' UNINST %s\n' $1; 121 endif 122endif 123 124pound := \# 125