1# SPDX-License-Identifier: GPL-2.0 2#### 3# kbuild: Generic definitions 4 5# Convenient variables 6comma := , 7quote := " 8squote := ' 9empty := 10space := $(empty) $(empty) 11space_escape := _-_SPACE_-_ 12pound := \# 13define newline 14 15 16endef 17 18### 19# Comparison macros. 20# Usage: $(call test-lt, $(CONFIG_LLD_VERSION), 150000) 21# 22# Use $(intcmp ...) if supported. (Make >= 4.4) 23# Otherwise, fall back to the 'test' shell command. 24ifeq ($(intcmp 1,0,,,y),y) 25test-ge = $(intcmp $(strip $1)0, $(strip $2)0,,y,y) 26test-gt = $(intcmp $(strip $1)0, $(strip $2)0,,,y) 27else 28test-ge = $(shell test $(strip $1)0 -ge $(strip $2)0 && echo y) 29test-gt = $(shell test $(strip $1)0 -gt $(strip $2)0 && echo y) 30endif 31test-le = $(call test-ge, $2, $1) 32test-lt = $(call test-gt, $2, $1) 33 34### 35# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o 36dot-target = $(dir $@).$(notdir $@) 37 38### 39# Name of target with a '.tmp_' as filename prefix. foo/bar.o => foo/.tmp_bar.o 40tmp-target = $(dir $@).tmp_$(notdir $@) 41 42### 43# The temporary file to save gcc -MMD generated dependencies must not 44# contain a comma 45depfile = $(subst $(comma),_,$(dot-target).d) 46 47### 48# filename of target with directory and extension stripped 49basetarget = $(basename $(notdir $@)) 50 51### 52# real prerequisites without phony targets 53real-prereqs = $(filter-out $(PHONY), $^) 54 55### 56# Escape single quote for use in echo statements 57escsq = $(subst $(squote),'\$(squote)',$1) 58 59### 60# Quote a string to pass it to C files. foo => '"foo"' 61stringify = $(squote)$(quote)$1$(quote)$(squote) 62 63### 64# The path to Kbuild or Makefile. Kbuild has precedence over Makefile. 65kbuild-dir = $(if $(filter /%,$(src)),$(src),$(srctree)/$(src)) 66kbuild-file = $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile) 67 68### 69# Read a file, replacing newlines with spaces 70# 71# Make 4.2 or later can read a file by using its builtin function. 72ifneq ($(filter-out 3.% 4.0 4.1, $(MAKE_VERSION)),) 73read-file = $(subst $(newline),$(space),$(file < $1)) 74else 75read-file = $(shell cat $1 2>/dev/null) 76endif 77 78### 79# Easy method for doing a status message 80 kecho := : 81 quiet_kecho := echo 82silent_kecho := : 83kecho := $($(quiet)kecho) 84 85### 86# filechk is used to check if the content of a generated file is updated. 87# Sample usage: 88# 89# filechk_sample = echo $(KERNELRELEASE) 90# version.h: FORCE 91# $(call filechk,sample) 92# 93# The rule defined shall write to stdout the content of the new file. 94# The existing file will be compared with the new one. 95# - If no file exist it is created 96# - If the content differ the new file is used 97# - If they are equal no change, and no timestamp update 98define filechk 99 $(check-FORCE) 100 $(Q)set -e; \ 101 mkdir -p $(dir $@); \ 102 trap "rm -f $(dot-target).tmp" EXIT; \ 103 { $(filechk_$(1)); } > $(dot-target).tmp; \ 104 if [ ! -r $@ ] || ! cmp -s $@ $(dot-target).tmp; then \ 105 $(kecho) ' UPD $@'; \ 106 mv -f $(dot-target).tmp $@; \ 107 fi 108endef 109 110### 111# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 112# Usage: 113# $(Q)$(MAKE) $(build)=dir 114build := -f $(srctree)/scripts/Makefile.build obj 115 116### 117# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj= 118# Usage: 119# $(Q)$(MAKE) $(dtbinst)=dir 120dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj 121 122### 123# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj= 124# Usage: 125# $(Q)$(MAKE) $(clean)=dir 126clean := -f $(srctree)/scripts/Makefile.clean obj 127 128# echo command. 129# Short version is used, if $(quiet) equals `quiet_', otherwise full one. 130echo-cmd = $(if $($(quiet)cmd_$(1)),\ 131 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';) 132 133# sink stdout for 'make -s' 134 redirect := 135 quiet_redirect := 136silent_redirect := exec >/dev/null; 137 138# Delete the target on interruption 139# 140# GNU Make automatically deletes the target if it has already been changed by 141# the interrupted recipe. So, you can safely stop the build by Ctrl-C (Make 142# will delete incomplete targets), and resume it later. 143# 144# However, this does not work when the stderr is piped to another program, like 145# $ make >&2 | tee log 146# Make dies with SIGPIPE before cleaning the targets. 147# 148# To address it, we clean the target in signal traps. 149# 150# Make deletes the target when it catches SIGHUP, SIGINT, SIGQUIT, SIGTERM. 151# So, we cover them, and also SIGPIPE just in case. 152# 153# Of course, this is unneeded for phony targets. 154delete-on-interrupt = \ 155 $(if $(filter-out $(PHONY), $@), \ 156 $(foreach sig, HUP INT QUIT TERM PIPE, \ 157 trap 'rm -f $@; trap - $(sig); kill -s $(sig) $$$$' $(sig);)) 158 159# printing commands 160cmd = @set -e; $(echo-cmd) $($(quiet)redirect) $(delete-on-interrupt) $(cmd_$(1)) 161 162### 163# if_changed - execute command if any prerequisite is newer than 164# target, or command line has changed 165# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 166# including used config symbols 167# if_changed_rule - as if_changed but execute rule instead 168# See Documentation/kbuild/makefiles.rst for more info 169 170ifneq ($(KBUILD_NOCMDDEP),1) 171# Check if both commands are the same including their order. Result is empty 172# string if equal. User may override this check using make KBUILD_NOCMDDEP=1 173cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \ 174 $(subst $(space),$(space_escape),$(strip $(cmd_$1)))) 175else 176cmd-check = $(if $(strip $(cmd_$@)),,1) 177endif 178 179# Replace >$< with >$$< to preserve $ when reloading the .cmd file 180# (needed for make) 181# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file 182# (needed for make) 183# Replace >'< with >'\''< to be able to enclose the whole string in '...' 184# (needed for the shell) 185make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1))))) 186 187# Find any prerequisites that are newer than target or that do not exist. 188# PHONY targets skipped in both cases. 189newer-prereqs = $(filter-out $(PHONY),$?) 190 191# It is a typical mistake to forget the FORCE prerequisite. Check it here so 192# no more breakage will slip in. 193check-FORCE = $(if $(filter FORCE, $^),,$(warning FORCE prerequisite is missing)) 194 195if-changed-cond = $(newer-prereqs)$(cmd-check)$(check-FORCE) 196 197# Execute command if command has changed or prerequisite(s) are updated. 198if_changed = $(if $(if-changed-cond),$(cmd_and_savecmd),@:) 199 200cmd_and_savecmd = \ 201 $(cmd); \ 202 printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd 203 204# Execute the command and also postprocess generated .d dependencies file. 205if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:) 206 207cmd_and_fixdep = \ 208 $(cmd); \ 209 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\ 210 rm -f $(depfile) 211 212# Usage: $(call if_changed_rule,foo) 213# Will check if $(cmd_foo) or any of the prerequisites changed, 214# and if so will execute $(rule_foo). 215if_changed_rule = $(if $(if-changed-cond),$(rule_$(1)),@:) 216 217### 218# why - tell why a target got built 219# enabled by make V=2 220# Output (listed in the order they are checked): 221# (1) - due to target is PHONY 222# (2) - due to target missing 223# (3) - due to: file1.h file2.h 224# (4) - due to command line change 225# (5) - due to missing .cmd file 226# (6) - due to target not in $(targets) 227# (1) PHONY targets are always build 228# (2) No target, so we better build it 229# (3) Prerequisite is newer than target 230# (4) The command line stored in the file named dir/.target.cmd 231# differed from actual command line. This happens when compiler 232# options changes 233# (5) No dir/.target.cmd file (used to store command line) 234# (6) No dir/.target.cmd file and target not listed in $(targets) 235# This is a good hint that there is a bug in the kbuild file 236ifeq ($(KBUILD_VERBOSE),2) 237why = \ 238 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ 239 $(if $(wildcard $@), \ 240 $(if $(newer-prereqs),- due to: $(newer-prereqs), \ 241 $(if $(cmd-check), \ 242 $(if $(cmd_$@),- due to command line change, \ 243 $(if $(filter $@, $(targets)), \ 244 - due to missing .cmd file, \ 245 - due to $(notdir $@) not in $$(targets) \ 246 ) \ 247 ) \ 248 ) \ 249 ), \ 250 - due to target missing \ 251 ) \ 252 ) 253 254echo-why = $(call escsq, $(strip $(why))) 255endif 256 257############################################################################### 258 259# delete partially updated (i.e. corrupted) files on error 260.DELETE_ON_ERROR: 261 262# do not delete intermediate files automatically 263# 264# .NOTINTERMEDIATE is more correct, but only available on newer Make versions. 265# Make 4.4 introduced .NOTINTERMEDIATE, and it appears in .FEATURES, but the 266# global .NOTINTERMEDIATE does not work. We can use it on Make > 4.4. 267# Use .SECONDARY for older Make versions, but "newer-prereq" cannot detect 268# deleted files. 269ifneq ($(and $(filter notintermediate, $(.FEATURES)),$(filter-out 4.4,$(MAKE_VERSION))),) 270.NOTINTERMEDIATE: 271else 272.SECONDARY: 273endif 274