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