Kbuild fixes for v5.4

- 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
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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

@@ -954,11 +954,6 @@ When kbuild executes, the following steps are followed (roughly):
 
 	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

@@ -498,10 +498,11 @@ build.
 	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.
 
@@ -521,7 +522,7 @@ build.
 		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

@@ -16,16 +16,21 @@ the kernel may be unreproducible, and how to avoid them.
 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
+* If enabled via ``CONFIG_IKHEADERS``, file timestamps of kernel
-using the `KBUILD_BUILD_TIMESTAMP`_ variable.  If you are building
+  headers embedded in the kernel or respective module,
-from a git commit, you could use its commit date.
+  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

@@ -206,24 +206,8 @@ ifndef KBUILD_CHECKSRC
   KBUILD_CHECKSRC = 0
 endif
 
-# Use make M=dir to specify directory of external module to build
+# Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the
-# Old syntax make ... SUBDIRS=$PWD is still supported
+# directory of external module to build. Setting M= takes precedence.
-# 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 ?= $(SUBDIRS)
-endif
-
 ifeq ("$(origin M)", "command line")
   KBUILD_EXTMOD := $(M)
 endif
@@ -498,7 +482,6 @@ export CFLAGS_KASAN CFLAGS_KASAN_NOSANITIZE CFLAGS_UBSAN
 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
 
@@ -914,9 +897,6 @@ 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
 include scripts/Makefile.ubsan

arch/powerpc/boot/Makefile

@@ -50,7 +50,7 @@ endif
 
 BOOTAFLAGS	:= -D__ASSEMBLY__ $(BOOTCFLAGS) -nostdinc
 
-BOOTARFLAGS	:= -cr$(KBUILD_ARFLAGS)
+BOOTARFLAGS	:= -crD
 
 ifdef CONFIG_CC_IS_CLANG
 BOOTCFLAGS += $(CLANG_FLAGS)

drivers/video/logo/Makefile

@@ -18,23 +18,6 @@ obj-$(CONFIG_SPU_BASE)			+= logo_spe_clut224.o
 
 # 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 ..."
@@ -55,5 +38,5 @@ $(obj)/%_clut224.c: $(src)/%_clut224.ppm $(pnmtologo) FORCE
 $(obj)/%_gray256.c: $(src)/%_gray256.pgm $(pnmtologo) FORCE
 	$(call if_changed,logo)
 
-# Files generated that shall be removed upon make clean
+# generated C files
-clean-files := *.o *_mono.c *_vga16.c *_clut224.c *_gray256.c
+targets += *_mono.c *_vga16.c *_clut224.c *_gray256.c

kernel/gen_kheaders.sh

@@ -71,7 +71,10 @@ done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1
 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

@@ -143,11 +143,6 @@ cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || e
 # 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

@@ -389,7 +389,7 @@ $(sort $(subdir-obj-y)): $(subdir-ym) ;
 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

@@ -232,7 +232,7 @@ quiet_cmd_ld = LD      $@
 # ---------------------------------------------------------------------------
 
 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

@@ -2652,15 +2652,20 @@ int main(int argc, char **argv)
 		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;
+
+		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;
 
-		while (s) {
 			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

@@ -65,13 +65,14 @@
 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 $srctree = File::Spec->curdir();
-my $objtree = "";
+my $objtree = File::Spec->curdir();
-$srctree = "$ENV{'srctree'}/" if (exists($ENV{'srctree'}));
+$srctree = File::Spec->rel2abs($ENV{'srctree'}) if (exists($ENV{'srctree'}));
-$objtree = "$ENV{'objtree'}/" if (exists($ENV{'objtree'}));
+$objtree = File::Spec->rel2abs($ENV{'objtree'}) if (exists($ENV{'objtree'}));
 
 if ($#ARGV != -1) {
 	print STDERR "usage: $0 takes no parameters\n";
@@ -231,9 +232,9 @@ sub do_nm
 	}
 	($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

@@ -126,7 +126,7 @@ scm_version()
 
 collect_files()
 {
-	local file res
+	local file res=
 
 	for file; do
 		case "$file" in

security/integrity/Makefile

@@ -13,9 +13,6 @@ integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyrin
 integrity-$(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

@@ -29,13 +29,11 @@ header-test- += linux/android/binderfs.h
 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
@@ -55,20 +53,12 @@ header-test- += linux/v4l2-mediabus.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