[PATCH 2/2] kbuild: sync scripts/Kbuild.include with Linux

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

The scripts/Kbuild.include file has a collection of helpers for use
across in Kbuild. Let's bring up our version in-sync with Linux
v6.13-rc1 by importing the following Linux commits:

  875ef1a57f kbuild: use .NOTINTERMEDIATE for future GNU Make versions
  174a1dcc96 kbuild: sink stdout from cmd for silent build
  a7f3257da8 kbuild: remove the target in signal traps when interrupted
  6768fa4bcb kbuild: add read-file macro
  fccb3d3eda kbuild: add test-{ge,gt,le,lt} macros
  8402ee182c kbuild: remove leftover comment for filechk utility
  12fec3d601 kbuild: replace $(dot-target).tmp in filechk with $(tmp-target)
  e1f86d7b4b kbuild: warn if FORCE is missing for filechk
  8962b6b475 kbuild: print short log in addition to the whole command with V=1
  6ae4b9868a kbuild: allow to combine multiple V= levels
  214c0eea43 kbuild: add $(objtree)/ prefix to some in-kernel build artifacts
---
 Makefile               |  19 ++++---
 scripts/Kbuild.include | 109 ++++++++++++++++++++++++++++++++++-------
 scripts/tags.sh        |   2 +-
 3 files changed, 102 insertions(+), 28 deletions(-)

diff --git a/Makefile b/Makefile
index 0b61d2875471..1516e5685cbf 100644
--- a/Makefile
+++ b/Makefile
@@ -66,9 +66,8 @@ unexport GREP_OPTIONS
 #
 #	$(Q)ln $@ :<
 #
-# If KBUILD_VERBOSE equals 0 then the above command will be hidden.
-# If KBUILD_VERBOSE equals 1 then the above command is displayed.
-# If KBUILD_VERBOSE equals 2 then give the reason why each target is rebuilt.
+# If KBUILD_VERBOSE contains 1, the whole command is echoed.
+# If KBUILD_VERBOSE contains 2, the reason for rebuilding is printed.
 #
 # To put more focus on warnings, be less verbose as default
 # Use 'make V=1' to see the full commands
@@ -80,12 +79,11 @@ ifndef KBUILD_VERBOSE
   KBUILD_VERBOSE = 0
 endif
 
-ifeq ($(KBUILD_VERBOSE),1)
+quiet = quiet_
+Q = @
+ifneq ($(findstring 1, $(KBUILD_VERBOSE)),)
   quiet =
   Q =
-else
-  quiet=quiet_
-  Q = @
 endif
 
 # If the user is running make -s (silent mode), suppress echoing of
@@ -317,7 +315,7 @@ include scripts/Kbuild.include
 include scripts/Makefile.compiler
 
 # Read KERNELRELEASE from include/config/kernel.release (if it exists)
-KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
+KERNELRELEASE = $(call read-file, include/config/kernel.release)
 KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
 BUILDSYSTEM_VERSION =
 export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION BUILDSYSTEM_VERSION
@@ -1326,8 +1324,9 @@ help:
 		printf "  %-24s - Build for %s\\n" $(b) $(subst _defconfig,,$(b));) \
 		echo '')
 
-	@echo  '  make V=0|1 [targets] 0 => quiet build (default), 1 => verbose build'
-	@echo  '  make V=2   [targets] 2 => give reason for rebuild of target'
+	@echo  '  make V=n   [targets] 0: quiet build (default), 1: verbose build'
+	@echo  '                       2: give reason for rebuild of target'
+	@echo  '                       V=1 and V=2 can be combined with V=12'
 	@echo  '  make O=dir [targets] Locate all output files in "dir", including .config'
 	@echo  '  make C=1   [targets] Check all c source with $$CHECK (sparse by default)'
 	@echo  '  make C=2   [targets] Force check of all c source with $$CHECK'
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 72c6a3c5d7d1..8c311b997e24 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -10,13 +10,37 @@ empty   :=
 space   := $(empty) $(empty)
 space_escape := _-_SPACE_-_
 pound := \#
+define newline
+
+
+endef
+
+###
+# Comparison macros.
+# Usage: $(call test-lt, $(CONFIG_LLD_VERSION), 150000)
+#
+# Use $(intcmp ...) if supported. (Make >= 4.4)
+# Otherwise, fall back to the 'test' shell command.
+ifeq ($(intcmp 1,0,,,y),y)
+test-ge = $(intcmp $(strip $1)0, $(strip $2)0,,y,y)
+test-gt = $(intcmp $(strip $1)0, $(strip $2)0,,,y)
+else
+test-ge = $(shell test $(strip $1)0 -ge $(strip $2)0 && echo y)
+test-gt = $(shell test $(strip $1)0 -gt $(strip $2)0 && echo y)
+endif
+test-le = $(call test-ge, $2, $1)
+test-lt = $(call test-gt, $2, $1)
 
 ###
 # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
 dot-target = $(dir $@).$(notdir $@)
 
 ###
-# The temporary file to save gcc -MD generated dependencies must not
+# Name of target with a '.tmp_' as filename prefix. foo/bar.o => foo/.tmp_bar.o
+tmp-target = $(dir $@).tmp_$(notdir $@)
+
+###
+# The temporary file to save gcc -MMD generated dependencies must not
 # contain a comma
 depfile = $(subst $(comma),_,$(dot-target).d)
 
@@ -36,6 +60,20 @@ escsq = $(subst $(squote),'\$(squote)',$1)
 # Quote a string to pass it to C files. foo => '"foo"'
 stringify = $(squote)$(quote)$1$(quote)$(squote)
 
+###
+# The path to Kbuild or Makefile. Kbuild has precedence over Makefile.
+kbuild-file = $(or $(wildcard $(src)/Kbuild),$(src)/Makefile)
+
+###
+# Read a file, replacing newlines with spaces
+#
+# Make 4.2 or later can read a file by using its builtin function.
+ifneq ($(filter-out 4.0 4.1, $(MAKE_VERSION)),)
+read-file = $(subst $(newline),$(space),$(file < $1))
+else
+read-file = $(shell cat $1 2>/dev/null)
+endif
+
 ###
 # Easy method for doing a status message
        kecho := :
@@ -56,16 +94,15 @@ kecho := $($(quiet)kecho)
 # - If no file exist it is created
 # - If the content differ the new file is used
 # - If they are equal no change, and no timestamp update
-# - stdin is piped in from the first prerequisite ($<) so one has
-#   to specify a valid file as first prerequisite (often the kbuild file)
 define filechk
+	$(check-FORCE)
 	$(Q)set -e;						\
 	mkdir -p $(dir $@);					\
-	trap "rm -f $(dot-target).tmp" EXIT;			\
-	{ $(filechk_$(1)); } > $(dot-target).tmp;		\
-	if [ ! -r $@ ] || ! cmp -s $@ $(dot-target).tmp; then	\
+	trap "rm -f $(tmp-target)" EXIT;			\
+	{ $(filechk_$(1)); } > $(tmp-target);			\
+	if [ ! -r $@ ] || ! cmp -s $@ $(tmp-target); then	\
 		$(kecho) '  UPD     $@';			\
-		mv -f $(dot-target).tmp $@;			\
+		mv -f $(tmp-target) $@;				\
 	fi
 endef
 
@@ -81,13 +118,39 @@ build := -f $(srctree)/scripts/Makefile.build obj
 # $(Q)$(MAKE) $(clean)=dir
 clean := -f $(srctree)/scripts/Makefile.clean obj
 
-# echo command.
-# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
-echo-cmd = $(if $($(quiet)cmd_$(1)),\
-	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
+# pring log
+#
+# If quiet is "silent_", print nothing and sink stdout
+# If quiet is "quiet_", print short log
+# If quiet is empty, print short log and whole command
+silent_log_print = exec >/dev/null;
+ quiet_log_print = $(if $(quiet_cmd_$1), echo '  $(call escsq,$(quiet_cmd_$1)$(why))';)
+       log_print = echo '$(pound) $(call escsq,$(or $(quiet_cmd_$1),cmd_$1 $@)$(why))'; \
+                   echo '  $(call escsq,$(cmd_$1))';
 
-# printing commands
-cmd = @set -e; $(echo-cmd) $(cmd_$(1))
+# Delete the target on interruption
+#
+# GNU Make automatically deletes the target if it has already been changed by
+# the interrupted recipe. So, you can safely stop the build by Ctrl-C (Make
+# will delete incomplete targets), and resume it later.
+#
+# However, this does not work when the stderr is piped to another program, like
+#  $ make >&2 | tee log
+# Make dies with SIGPIPE before cleaning the targets.
+#
+# To address it, we clean the target in signal traps.
+#
+# Make deletes the target when it catches SIGHUP, SIGINT, SIGQUIT, SIGTERM.
+# So, we cover them, and also SIGPIPE just in case.
+#
+# Of course, this is unneeded for phony targets.
+delete-on-interrupt = \
+	$(if $(filter-out $(PHONY), $@), \
+		$(foreach sig, HUP INT QUIT TERM PIPE, \
+			trap 'rm -f $@; trap - $(sig); kill -s $(sig) $$$$' $(sig);))
+
+# print and execute commands
+cmd = @$(if $(cmd_$(1)),set -e; $($(quiet)log_print) $(delete-on-interrupt) $(cmd_$(1)),:)
 
 ###
 # if_changed      - execute command if any prerequisite is newer than
@@ -142,7 +205,7 @@ if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:)
 
 cmd_and_fixdep =                                                             \
 	$(cmd);                                                              \
-	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
+	$(objtree)/scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
 	rm -f $(depfile)
 
 # Usage: $(call if_changed_rule,foo)
@@ -169,8 +232,8 @@ if_changed_rule = $(if $(if-changed-cond),$(rule_$(1)),@:)
 # (5) No dir/.target.cmd file (used to store command line)
 # (6) No dir/.target.cmd file and target not listed in $(targets)
 #     This is a good hint that there is a bug in the kbuild file
-ifeq ($(KBUILD_VERBOSE),2)
-why =                                                                        \
+ifneq ($(findstring 2, $(KBUILD_VERBOSE)),)
+_why =                                                                        \
     $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
         $(if $(wildcard $@),                                                 \
             $(if $(newer-prereqs),- due to: $(newer-prereqs),                \
@@ -187,11 +250,23 @@ why =                                                                        \
          )                                                                   \
      )
 
-echo-why = $(call escsq, $(strip $(why)))
+why = $(space)$(strip $(_why))
 endif
 
+###############################################################################
+
 # delete partially updated (i.e. corrupted) files on error
 .DELETE_ON_ERROR:
 
 # do not delete intermediate files automatically
+#
+# .NOTINTERMEDIATE is more correct, but only available on newer Make versions.
+# Make 4.4 introduced .NOTINTERMEDIATE, and it appears in .FEATURES, but the
+# global .NOTINTERMEDIATE does not work. We can use it on Make > 4.4.
+# Use .SECONDARY for older Make versions, but "newer-prereq" cannot detect
+# deleted files.
+ifneq ($(and $(filter notintermediate, $(.FEATURES)),$(filter-out 4.4,$(MAKE_VERSION))),)
+.NOTINTERMEDIATE:
+else
 .SECONDARY:
+endif
diff --git a/scripts/tags.sh b/scripts/tags.sh
index 4e18ae5282a6..6e0e0a7c2270 100755
--- a/scripts/tags.sh
+++ b/scripts/tags.sh
@@ -8,7 +8,7 @@
 # Uses the following environment variables:
 # SUBARCH, SRCARCH, srctree
 
-if [ "$KBUILD_VERBOSE" = "1" ]; then
+if [[ "$KBUILD_VERBOSE" =~ "1" ]]; then
 	set -x
 fi
 
-- 
2.39.5