Merge tag 'kbuild-fixes-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

- remove unneeded ar-option and KBUILD_ARFLAGS

- remove long-deprecated SUBDIRS

- fix modpost to suppress false-positive warnings for UML builds

- fix namespace.pl to handle relative paths to ${objtree}, ${srctree}

- make setlocalversion work for /bin/sh

- make header archive reproducible

- fix some Makefiles and documents

* tag 'kbuild-fixes-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kheaders: make headers archive reproducible
kbuild: update compile-test header list for v5.4-rc2
kbuild: two minor updates for Documentation/kbuild/modules.rst
scripts/setlocalversion: clear local variable to make it work for sh
namespace: fix namespace.pl script to support relative paths
video/logo: do not generate unneeded logo C files
video/logo: remove unneeded *.o pattern from clean-files
integrity: remove pointless subdir-$(CONFIG_...)
integrity: remove unneeded, broken attempt to add -fshort-wchar
modpost: fix static EXPORT_SYMBOL warnings for UML build
kbuild: correct formatting of header in kbuild module docs
kbuild: remove SUBDIRS support
kbuild: remove ar-option and KBUILD_ARFLAGS

Documentation/kbuild/makefiles.rst

···
 
 	From commandline LDFLAGS_MODULE shall be used (see kbuild.txt).
 
-    KBUILD_ARFLAGS   Options for $(AR) when creating archives
-
-	$(KBUILD_ARFLAGS) set by the top level Makefile to "D" (deterministic
-	mode) if this option is supported by $(AR).
-
     KBUILD_LDS
 
 	The linker script with full path. Assigned by the top-level Makefile.

Documentation/kbuild/modules.rst

···
 	will be written containing all exported symbols that were not
 	defined in the kernel.
 
---- 6.3 Symbols From Another External Module
+6.3 Symbols From Another External Module
+----------------------------------------
 
 	Sometimes, an external module uses exported symbols from
-	another external module. kbuild needs to have full knowledge of
+	another external module. Kbuild needs to have full knowledge of
 	all symbols to avoid spitting out warnings about undefined
 	symbols. Three solutions exist for this situation.
 
···
 		The top-level kbuild file would then look like::
 
 			#./Kbuild (or ./Makefile):
-				obj-y := foo/ bar/
+				obj-m := foo/ bar/
 
 		And executing::
 

Documentation/kbuild/reproducible-builds.rst

···
 Timestamps
 ----------
 
-The kernel embeds a timestamp in two places:
+The kernel embeds timestamps in three places:
 
 * The version string exposed by ``uname()`` and included in
   ``/proc/version``
 
 * File timestamps in the embedded initramfs
 
-By default the timestamp is the current time.  This must be overridden
-using the `KBUILD_BUILD_TIMESTAMP`_ variable.  If you are building
-from a git commit, you could use its commit date.
+* If enabled via ``CONFIG_IKHEADERS``, file timestamps of kernel
+  headers embedded in the kernel or respective module,
+  exposed via ``/sys/kernel/kheaders.tar.xz``
+
+By default the timestamp is the current time and in the case of
+``kheaders`` the various files' modification times. This must
+be overridden using the `KBUILD_BUILD_TIMESTAMP`_ variable.
+If you are building from a git commit, you could use its commit date.
 
 The kernel does *not* use the ``__DATE__`` and ``__TIME__`` macros,
 and enables warnings if they are used.  If you incorporate external

Makefile

···
   KBUILD_CHECKSRC = 0
 endif
 
-# Use make M=dir to specify directory of external module to build
-# Old syntax make ... SUBDIRS=$PWD is still supported
-# Setting the environment variable KBUILD_EXTMOD take precedence
-ifdef SUBDIRS
-  $(warning ================= WARNING ================)
-  $(warning 'SUBDIRS' will be removed after Linux 5.3)
-  $(warning )
-  $(warning If you are building an individual subdirectory)
-  $(warning in the kernel tree, you can do like this:)
-  $(warning $$ make path/to/dir/you/want/to/build/)
-  $(warning (Do not forget the trailing slash))
-  $(warning )
-  $(warning If you are building an external module,)
-  $(warning Please use 'M=' or 'KBUILD_EXTMOD' instead)
-  $(warning ==========================================)
-  KBUILD_EXTMOD ?= $(SUBDIRS)
-endif
-
+# Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the
+# directory of external module to build. Setting M= takes precedence.
 ifeq ("$(origin M)", "command line")
   KBUILD_EXTMOD := $(M)
 endif
···
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
 export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
-export KBUILD_ARFLAGS
 
 # Files to ignore in find ... statements
 
···
 ifdef CONFIG_RETPOLINE
 KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
 endif
-
-# use the deterministic mode of AR if available
-KBUILD_ARFLAGS := $(call ar-option,D)
 
 include scripts/Makefile.kasan
 include scripts/Makefile.extrawarn

arch/powerpc/boot/Makefile

···
 
 BOOTAFLAGS	:= -D__ASSEMBLY__ $(BOOTCFLAGS) -nostdinc
 
-BOOTARFLAGS	:= -cr$(KBUILD_ARFLAGS)
+BOOTARFLAGS	:= -crD
 
 ifdef CONFIG_CC_IS_CLANG
 BOOTCFLAGS += $(CLANG_FLAGS)

drivers/video/logo/Makefile

···
 
 # How to generate logo's
 
-# Use logo-cfiles to retrieve list of .c files to be built
-logo-cfiles = $(notdir $(patsubst %.$(2), %.c, \
-              $(wildcard $(srctree)/$(src)/*$(1).$(2))))
-
-
-# Mono logos
-extra-y += $(call logo-cfiles,_mono,pbm)
-
-# VGA16 logos
-extra-y += $(call logo-cfiles,_vga16,ppm)
-
-# 224 Logos
-extra-y += $(call logo-cfiles,_clut224,ppm)
-
-# Gray 256
-extra-y += $(call logo-cfiles,_gray256,pgm)
-
 pnmtologo := scripts/pnmtologo
 
 # Create commands like "pnmtologo -t mono -n logo_mac_mono -o ..."
···
 $(obj)/%_gray256.c: $(src)/%_gray256.pgm $(pnmtologo) FORCE
 	$(call if_changed,logo)
 
-# Files generated that shall be removed upon make clean
-clean-files := *.o *_mono.c *_vga16.c *_clut224.c *_gray256.c
+# generated C files
+targets += *_mono.c *_vga16.c *_clut224.c *_gray256.c

kernel/gen_kheaders.sh

···
 find $cpio_dir -type f -print0 |
 	xargs -0 -P8 -n1 perl -pi -e 'BEGIN {undef $/;}; s/\/\*((?!SPDX).)*?\*\///smg;'
 
-tar -Jcf $tarfile -C $cpio_dir/ . > /dev/null
+# Create archive and try to normalize metadata for reproducibility
+tar "${KBUILD_BUILD_TIMESTAMP:+--mtime=$KBUILD_BUILD_TIMESTAMP}" \
+    --owner=0 --group=0 --sort=name --numeric-owner \
+    -Jcf $tarfile -C $cpio_dir/ . > /dev/null
 
 echo "$src_files_md5" >  kernel/kheaders.md5
 echo "$obj_files_md5" >> kernel/kheaders.md5

scripts/Kbuild.include

···
 # Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
 ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
 
-# ar-option
-# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
-# Important: no spaces around options
-ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
-
 # ld-version
 # Note this is mainly for HJ Lu's 3 number binutil versions
 ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh)

scripts/Makefile.build

···
 ifdef builtin-target
 
 quiet_cmd_ar_builtin = AR      $@
-      cmd_ar_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
+      cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs)
 
 $(builtin-target): $(real-obj-y) FORCE
 	$(call if_changed,ar_builtin)

scripts/Makefile.lib

···
 # ---------------------------------------------------------------------------
 
 quiet_cmd_ar = AR      $@
-      cmd_ar = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
+      cmd_ar = rm -f $@; $(AR) cDPrsT $@ $(real-prereqs)
 
 # Objcopy
 # ---------------------------------------------------------------------------

scripts/mod/modpost.c

···
 		fatal("modpost: Section mismatches detected.\n"
 		      "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
 	for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
-		struct symbol *s = symbolhash[n];
+		struct symbol *s;
 
-		while (s) {
+		for (s = symbolhash[n]; s; s = s->next) {
+			/*
+			 * Do not check "vmlinux". This avoids the same warnings
+			 * shown twice, and false-positives for ARCH=um.
+			 */
+			if (is_vmlinux(s->module->name) && !s->module->is_dot_o)
+				continue;
+
 			if (s->is_static)
 				warn("\"%s\" [%s] is a static %s\n",
 				     s->name, s->module->name,
 				     export_str(s->export));
-
-			s = s->next;
 		}
 	}
 

scripts/namespace.pl

···
 use warnings;
 use strict;
 use File::Find;
+use File::Spec;
 
 my $nm = ($ENV{'NM'} || "nm") . " -p";
 my $objdump = ($ENV{'OBJDUMP'} || "objdump") . " -s -j .comment";
-my $srctree = "";
-my $objtree = "";
-$srctree = "$ENV{'srctree'}/" if (exists($ENV{'srctree'}));
-$objtree = "$ENV{'objtree'}/" if (exists($ENV{'objtree'}));
+my $srctree = File::Spec->curdir();
+my $objtree = File::Spec->curdir();
+$srctree = File::Spec->rel2abs($ENV{'srctree'}) if (exists($ENV{'srctree'}));
+$objtree = File::Spec->rel2abs($ENV{'objtree'}) if (exists($ENV{'objtree'}));
 
 if ($#ARGV != -1) {
 	print STDERR "usage: $0 takes no parameters\n";
···
 	}
 	($source = $basename) =~ s/\.o$//;
 	if (-e "$source.c" || -e "$source.S") {
-		$source = "$objtree$File::Find::dir/$source";
+		$source = File::Spec->catfile($objtree, $File::Find::dir, $source)
 	} else {
-		$source = "$srctree$File::Find::dir/$source";
+		$source = File::Spec->catfile($srctree, $File::Find::dir, $source)
 	}
 	if (! -e "$source.c" && ! -e "$source.S") {
 		# No obvious source, exclude the object if it is conglomerate

scripts/setlocalversion

···
 
 collect_files()
 {
-	local file res
+	local file res=
 
 	for file; do
 		case "$file" in

security/integrity/Makefile

···
 integrity-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/efi_parser.o \
 					platform_certs/load_uefi.o
 integrity-$(CONFIG_LOAD_IPL_KEYS) += platform_certs/load_ipl_s390.o
-$(obj)/load_uefi.o: KBUILD_CFLAGS += -fshort-wchar
 
-subdir-$(CONFIG_IMA)			+= ima
 obj-$(CONFIG_IMA)			+= ima/
-subdir-$(CONFIG_EVM)			+= evm
 obj-$(CONFIG_EVM)			+= evm/

usr/include/Makefile

···
 header-test-$(CONFIG_CPU_BIG_ENDIAN) += linux/byteorder/big_endian.h
 header-test-$(CONFIG_CPU_LITTLE_ENDIAN) += linux/byteorder/little_endian.h
 header-test- += linux/coda.h
-header-test- += linux/coda_psdev.h
 header-test- += linux/elfcore.h
 header-test- += linux/errqueue.h
 header-test- += linux/fsmap.h
 header-test- += linux/hdlc/ioctl.h
 header-test- += linux/ivtv.h
-header-test- += linux/jffs2.h
 header-test- += linux/kexec.h
 header-test- += linux/matroxfb.h
 header-test- += linux/netfilter_ipv4/ipt_LOG.h
···
 header-test- += linux/v4l2-subdev.h
 header-test- += linux/videodev2.h
 header-test- += linux/vm_sockets.h
-header-test- += scsi/scsi_bsg_fc.h
-header-test- += scsi/scsi_netlink.h
-header-test- += scsi/scsi_netlink_fc.h
 header-test- += sound/asequencer.h
 header-test- += sound/asoc.h
 header-test- += sound/asound.h
 header-test- += sound/compress_offload.h
 header-test- += sound/emu10k1.h
 header-test- += sound/sfnt_info.h
-header-test- += sound/sof/eq.h
-header-test- += sound/sof/fw.h
-header-test- += sound/sof/header.h
-header-test- += sound/sof/manifest.h
-header-test- += sound/sof/trace.h
 header-test- += xen/evtchn.h
 header-test- += xen/gntdev.h
 header-test- += xen/privcmd.h