Merge tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Remove potentially incomplete targets when Kbuid is interrupted by
   SIGINT etc in case GNU Make may miss to do that when stderr is piped
   to another program.

 - Rewrite the single target build so it works more correctly.

 - Fix rpm-pkg builds with V=1.

 - List top-level subdirectories in ./Kbuild.

 - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in
   kallsyms.

 - Avoid two different modules in lib/zstd/ having shared code, which
   potentially causes building the common code as build-in and modular
   back-and-forth.

 - Unify two modpost invocations to optimize the build process.

 - Remove head-y syntax in favor of linker scripts for placing
   particular sections in the head of vmlinux.

 - Bump the minimal GNU Make version to 3.82.

 - Clean up misc Makefiles and scripts.

* tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits)
  docs: bump minimal GNU Make version to 3.82
  ia64: simplify esi object addition in Makefile
  Revert "kbuild: Check if linker supports the -X option"
  kbuild: rebuild .vmlinux.export.o when its prerequisite is updated
  kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o
  zstd: Fixing mixed module-builtin objects
  kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols
  kallsyms: take the input file instead of reading stdin
  kallsyms: drop duplicated ignore patterns from kallsyms.c
  kbuild: reuse mksysmap output for kallsyms
  mksysmap: update comment about __crc_*
  kbuild: remove head-y syntax
  kbuild: use obj-y instead extra-y for objects placed at the head
  kbuild: hide error checker logs for V=1 builds
  kbuild: re-run modpost when it is updated
  kbuild: unify two modpost invocations
  kbuild: move vmlinux.o rule to the top Makefile
  kbuild: move .vmlinux.objs rule to Makefile.modpost
  kbuild: list sub-directories in ./Kbuild
  Makefile.compiler: replace cc-ifversion with compiler-specific macros
  ...

1 files changed, 22 insertions, 1 deletions

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index ece44b735061..2bc08ace38a3 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -100,8 +100,29 @@ echo-cmd = $(if $($(quiet)cmd_$(1)),\
  quiet_redirect :=
 silent_redirect := exec >/dev/null;
 
+# 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);))
+
 # printing commands
-cmd = @set -e; $(echo-cmd) $($(quiet)redirect) $(cmd_$(1))
+cmd = @set -e; $(echo-cmd) $($(quiet)redirect) $(delete-on-interrupt) $(cmd_$(1))
 
 ###
 # if_changed      - execute command if any prerequisite is newer than