Merge tag 'kbuild-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:
 "Build system:

   - add CONFIG_UNUSED_KSYMS_WHITELIST, which will be useful to define a
     fixed set of export symbols for Generic Kernel Image (GKI)

   - allow to run 'make dt_binding_check' without .config

   - use full schema for checking DT examples in *.yaml files

   - make modpost fail for missing MODULE_IMPORT_NS(), which makes more
     sense because we know the produced modules are never loadable

   - Remove unused 'AS' variable

  Kconfig:

   - sanitize DEFCONFIG_LIST, and remove ARCH_DEFCONFIG from Kconfig
     files

   - relax the 'imply' behavior so that symbols implied by 'y' can
     become 'm'

   - make 'imply' obey 'depends on' in order to make 'imply' really weak

  Misc:

   - add documentation on building the kernel with Clang/LLVM

   - revive __HAVE_ARCH_STRLEN for 32bit sparc to use optimized strlen()

   - fix warning from deb-pkg builds when CONFIG_DEBUG_INFO=n

   - various script and Makefile cleanups"

* tag 'kbuild-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits)
  Makefile: Update kselftest help information
  kbuild: deb-pkg: fix warning when CONFIG_DEBUG_INFO is unset
  kbuild: add outputmakefile to no-dot-config-targets
  kbuild: remove AS variable
  net: wan: wanxl: refactor the firmware rebuild rule
  net: wan: wanxl: use $(M68KCC) instead of $(M68KAS) for rebuilding firmware
  net: wan: wanxl: use allow to pass CROSS_COMPILE_M68k for rebuilding firmware
  kbuild: add comment about grouped target
  kbuild: add -Wall to KBUILD_HOSTCXXFLAGS
  kconfig: remove unused variable in qconf.cc
  sparc: revive __HAVE_ARCH_STRLEN for 32bit sparc
  kbuild: refactor Makefile.dtbinst more
  kbuild: compute the dtbs_install destination more simply
  Makefile: disallow data races on gcc-10 as well
  kconfig: make 'imply' obey the direct dependency
  kconfig: allow symbols implied by y to become m
  net: drop_monitor: use IS_REACHABLE() to guard net_dm_hw_report()
  modpost: return error if module is missing ns imports and MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n
  modpost: rework and consolidate logging interface
  kbuild: allow to run dt_binding_check without kernel configuration
  ...

35 files changed, 356 insertions, 200 deletions

diff --git a/Documentation/Makefile b/Documentation/Makefile
index 79ecee62d597..cc786d11a028 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -2,7 +2,8 @@
 # Makefile for Sphinx documentation
 #
 
-subdir-y := devicetree/bindings/
+# for cleaning
+subdir- := devicetree/bindings
 
 # Check for broken documentation file references
 ifeq ($(CONFIG_WARN_MISSING_DOCUMENTS),y)
diff --git a/Documentation/devicetree/bindings/.gitignore b/Documentation/devicetree/bindings/.gitignore
index ef82fcfcccab..57afa1533a5f 100644
--- a/Documentation/devicetree/bindings/.gitignore
+++ b/Documentation/devicetree/bindings/.gitignore
@@ -1,2 +1,2 @@
 *.example.dts
-processed-schema.yaml
+processed-schema*.yaml
diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile
index 646cb3525373..1df680d07461 100644
--- a/Documentation/devicetree/bindings/Makefile
+++ b/Documentation/devicetree/bindings/Makefile
@@ -2,7 +2,6 @@
 DT_DOC_CHECKER ?= dt-doc-validate
 DT_EXTRACT_EX ?= dt-extract-example
 DT_MK_SCHEMA ?= dt-mk-schema
-DT_MK_SCHEMA_FLAGS := $(if $(DT_SCHEMA_FILES), -u)
 
 quiet_cmd_chk_binding = CHKDT   $(patsubst $(srctree)/%,%,$<)
       cmd_chk_binding = $(DT_DOC_CHECKER) -u $(srctree)/$(src) $< ; \
@@ -11,26 +10,35 @@ quiet_cmd_chk_binding = CHKDT   $(patsubst $(srctree)/%,%,$<)
 $(obj)/%.example.dts: $(src)/%.yaml FORCE
 	$(call if_changed,chk_binding)
 
-DT_TMP_SCHEMA := processed-schema.yaml
+# Use full schemas when checking %.example.dts
+DT_TMP_SCHEMA := $(obj)/processed-schema-examples.yaml
 
 quiet_cmd_mk_schema = SCHEMA  $@
       cmd_mk_schema = $(DT_MK_SCHEMA) $(DT_MK_SCHEMA_FLAGS) -o $@ $(real-prereqs)
 
-DT_DOCS = $(shell \
+DT_DOCS = $(addprefix $(src)/, \
+	$(shell \
 	cd $(srctree)/$(src) && \
 	find * \( -name '*.yaml' ! \
-		-name $(DT_TMP_SCHEMA) ! \
+		-name 'processed-schema*' ! \
 		-name '*.example.dt.yaml' \) \
-	)
+	))
 
-DT_SCHEMA_FILES ?= $(addprefix $(src)/,$(DT_DOCS))
+DT_SCHEMA_FILES ?= $(DT_DOCS)
 
-ifeq ($(CHECK_DTBS),)
-extra-y += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES))
-extra-y += $(patsubst $(src)/%.yaml,%.example.dt.yaml, $(DT_SCHEMA_FILES))
-endif
+extra-$(CHECK_DT_BINDING) += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES))
+extra-$(CHECK_DT_BINDING) += $(patsubst $(src)/%.yaml,%.example.dt.yaml, $(DT_SCHEMA_FILES))
+extra-$(CHECK_DT_BINDING) += processed-schema-examples.yaml
 
-$(obj)/$(DT_TMP_SCHEMA): $(DT_SCHEMA_FILES) FORCE
+override DTC_FLAGS := \
+	-Wno-avoid_unnecessary_addr_size \
+	-Wno-graph_child_address
+
+$(obj)/processed-schema-examples.yaml: $(DT_DOCS) FORCE
+	$(call if_changed,mk_schema)
+
+$(obj)/processed-schema.yaml: DT_MK_SCHEMA_FLAGS := -u
+$(obj)/processed-schema.yaml: $(DT_SCHEMA_FILES) FORCE
 	$(call if_changed,mk_schema)
 
-extra-y += $(DT_TMP_SCHEMA)
+extra-y += processed-schema.yaml
diff --git a/Documentation/devicetree/writing-schema.rst b/Documentation/devicetree/writing-schema.rst
index 7635ab230456..220cf464ed77 100644
--- a/Documentation/devicetree/writing-schema.rst
+++ b/Documentation/devicetree/writing-schema.rst
@@ -147,6 +147,10 @@ Note that ``dtbs_check`` will skip any binding schema files with errors. It is
 necessary to use ``dt_binding_check`` to get all the validation errors in the
 binding schema files.
 
+It is possible to run both in a single command::
+
+    make dt_binding_check dtbs_check
+
 It is also possible to run checks with a single schema file by setting the
 ``DT_SCHEMA_FILES`` variable to a specific schema file.
 
diff --git a/Documentation/kbuild/index.rst b/Documentation/kbuild/index.rst
index 82daf2efcb73..cee2f99f734b 100644
--- a/Documentation/kbuild/index.rst
+++ b/Documentation/kbuild/index.rst
@@ -20,6 +20,7 @@ Kernel Build System
     issues
     reproducible-builds
     gcc-plugins
+    llvm
 
 .. only::  subproject and html
 
diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst
index d0111dd26410..a1601ec3317b 100644
--- a/Documentation/kbuild/kconfig-language.rst
+++ b/Documentation/kbuild/kconfig-language.rst
@@ -159,11 +159,11 @@ applicable everywhere (see syntax).
   Given the following example::
 
     config FOO
-	tristate
+	tristate "foo"
 	imply BAZ
 
     config BAZ
-	tristate
+	tristate "baz"
 	depends on BAR
 
   The following values are possible:
@@ -173,7 +173,10 @@ applicable everywhere (see syntax).
 	===		===		=============	==============
 	n		y		n		N/m/y
 	m		y		m		M/y/n
-	y		y		y		Y/n
+	y		y		y		Y/m/n
+	n		m		n		N/m
+	m		m		m		M/n
+	y		m		n		M/n
 	y		n		*		N
 	===		===		=============	==============
 
@@ -181,6 +184,24 @@ applicable everywhere (see syntax).
   ability to hook into a secondary subsystem while allowing the user to
   configure that subsystem out without also having to unset these drivers.
 
+  Note: If the combination of FOO=y and BAR=m causes a link error,
+  you can guard the function call with IS_REACHABLE()::
+
+	foo_init()
+	{
+		if (IS_REACHABLE(CONFIG_BAZ))
+			baz_register(&foo);
+		...
+	}
+
+  Note: If the feature provided by BAZ is highly desirable for FOO,
+  FOO should imply not only BAZ, but also its dependency BAR::
+
+    config FOO
+	tristate "foo"
+	imply BAR
+	imply BAZ
+
 - limiting menu display: "visible if" <expr>
 
   This attribute is only applicable to menu blocks, if the condition is
diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst
new file mode 100644
index 000000000000..d6c79eb4e23e
--- /dev/null
+++ b/Documentation/kbuild/llvm.rst
@@ -0,0 +1,80 @@
+==============================
+Building Linux with Clang/LLVM
+==============================
+
+This document covers how to build the Linux kernel with Clang and LLVM
+utilities.
+
+About
+-----
+
+The Linux kernel has always traditionally been compiled with GNU toolchains
+such as GCC and binutils. Ongoing work has allowed for `Clang
+<https://clang.llvm.org/>`_ and `LLVM <https://llvm.org/>`_ utilities to be
+used as viable substitutes. Distributions such as `Android
+<https://www.android.com/>`_, `ChromeOS
+<https://www.chromium.org/chromium-os>`_, and `OpenMandriva
+<https://www.openmandriva.org/>`_ use Clang built kernels.  `LLVM is a
+collection of toolchain components implemented in terms of C++ objects
+<https://www.aosabook.org/en/llvm.html>`_. Clang is a front-end to LLVM that
+supports C and the GNU C extensions required by the kernel, and is pronounced
+"klang," not "see-lang."
+
+Clang
+-----
+
+The compiler used can be swapped out via `CC=` command line argument to `make`.
+`CC=` should be set when selecting a config and during a build.
+
+	make CC=clang defconfig
+
+	make CC=clang
+
+Cross Compiling
+---------------
+
+A single Clang compiler binary will typically contain all supported backends,
+which can help simplify cross compiling.
+
+	ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make CC=clang
+
+`CROSS_COMPILE` is not used to prefix the Clang compiler binary, instead
+`CROSS_COMPILE` is used to set a command line flag: `--target <triple>`. For
+example:
+
+	clang --target aarch64-linux-gnu foo.c
+
+LLVM Utilities
+--------------
+
+LLVM has substitutes for GNU binutils utilities. These can be invoked as
+additional parameters to `make`.
+
+	make CC=clang AS=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \\
+	  OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump OBJSIZE=llvm-objsize \\
+	  READELF=llvm-readelf HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar \\
+	  HOSTLD=ld.lld
+
+Getting Help
+------------
+
+- `Website <https://clangbuiltlinux.github.io/>`_
+- `Mailing List <https://groups.google.com/forum/#!forum/clang-built-linux>`_: <clang-built-linux@googlegroups.com>
+- `Issue Tracker <https://github.com/ClangBuiltLinux/linux/issues>`_
+- IRC: #clangbuiltlinux on chat.freenode.net
+- `Telegram <https://t.me/ClangBuiltLinux>`_: @ClangBuiltLinux
+- `Wiki <https://github.com/ClangBuiltLinux/linux/wiki>`_
+- `Beginner Bugs <https://github.com/ClangBuiltLinux/linux/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22>`_
+
+Getting LLVM
+-------------
+
+- http://releases.llvm.org/download.html
+- https://github.com/llvm/llvm-project
+- https://llvm.org/docs/GettingStarted.html
+- https://llvm.org/docs/CMake.html
+- https://apt.llvm.org/
+- https://www.archlinux.org/packages/extra/x86_64/llvm/
+- https://github.com/ClangBuiltLinux/tc-build
+- https://github.com/ClangBuiltLinux/linux/wiki/Building-Clang-from-source
+- https://android.googlesource.com/platform/prebuilts/clang/host/linux-x86/
diff --git a/MAINTAINERS b/MAINTAINERS
index 78c782a43b9d..78b53ce0adfb 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4139,6 +4139,7 @@ B:	https://github.com/ClangBuiltLinux/linux/issues
 C:	irc://chat.freenode.net/clangbuiltlinux
 S:	Supported
 K:	\b(?i:clang|llvm)\b
+F:	Documentation/kbuild/llvm.rst
 
 CLEANCACHE API
 M:	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/Makefile b/Makefile
index 4d0711f54047..c91342953d9e 100644
--- a/Makefile
+++ b/Makefile
@@ -255,7 +255,8 @@ clean-targets := %clean mrproper cleandocs
 no-dot-config-targets := $(clean-targets) \
 			 cscope gtags TAGS tags help% %docs check% coccicheck \
 			 $(version_h) headers headers_% archheaders archscripts \
-			 %asm-generic kernelversion %src-pkg
+			 %asm-generic kernelversion %src-pkg dt_binding_check \
+			 outputmakefile
 no-sync-config-targets := $(no-dot-config-targets) install %install \
 			   kernelrelease
 single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.s %.symtypes %/
@@ -388,6 +389,9 @@ endif
 KCONFIG_CONFIG	?= .config
 export KCONFIG_CONFIG
 
+# Default file for 'make defconfig'. This may be overridden by arch-Makefile.
+export KBUILD_DEFCONFIG := defconfig
+
 # SHELL used by kbuild
 CONFIG_SHELL := sh
 
@@ -400,12 +404,11 @@ HOSTCXX      = g++
 KBUILD_HOSTCFLAGS   := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 \
 		-fomit-frame-pointer -std=gnu89 $(HOST_LFS_CFLAGS) \
 		$(HOSTCFLAGS)
-KBUILD_HOSTCXXFLAGS := -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
+KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
 KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
 KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
 
 # Make variables (CC, etc...)
-AS		= $(CROSS_COMPILE)as
 LD		= $(CROSS_COMPILE)ld
 CC		= $(CROSS_COMPILE)gcc
 CPP		= $(CC) -E
@@ -472,7 +475,7 @@ KBUILD_LDFLAGS :=
 GCC_PLUGINS_CFLAGS :=
 CLANG_FLAGS :=
 
-export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC
+export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP OBJSIZE READELF PAHOLE LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
@@ -535,7 +538,7 @@ endif
 ifneq ($(GCC_TOOLCHAIN),)
 CLANG_FLAGS	+= --gcc-toolchain=$(GCC_TOOLCHAIN)
 endif
-ifeq ($(shell $(AS) --version 2>&1 | head -n 1 | grep clang),)
+ifeq ($(if $(AS),$(shell $(AS) --version 2>&1 | head -n 1 | grep clang)),)
 CLANG_FLAGS	+= -no-integrated-as
 endif
 CLANG_FLAGS	+= -Werror=unknown-warning-option
@@ -674,6 +677,7 @@ $(KCONFIG_CONFIG):
 #
 # This exploits the 'multi-target pattern rule' trick.
 # The syncconfig should be executed only once to make all the targets.
+# (Note: use the grouped target '&:' when we bump to GNU Make 4.3)
 %/auto.conf %/auto.conf.cmd: $(KCONFIG_CONFIG)
 	$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig
 else # !may-sync-config
@@ -714,6 +718,7 @@ endif
 
 # Tell gcc to never replace conditional load with a non-conditional one
 KBUILD_CFLAGS	+= $(call cc-option,--param=allow-store-data-races=0)
+KBUILD_CFLAGS	+= $(call cc-option,-fno-allow-store-data-races)
 
 include scripts/Makefile.kcov
 include scripts/Makefile.gcc-plugins
@@ -729,7 +734,7 @@ KBUILD_CFLAGS += $(call cc-option,-fno-reorder-blocks,) \
 endif
 
 ifneq ($(CONFIG_FRAME_WARN),0)
-KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
+KBUILD_CFLAGS += -Wframe-larger-than=$(CONFIG_FRAME_WARN)
 endif
 
 stackp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector
@@ -1063,9 +1068,12 @@ endif
 
 autoksyms_h := $(if $(CONFIG_TRIM_UNUSED_KSYMS), include/generated/autoksyms.h)
 
+quiet_cmd_autoksyms_h = GEN     $@
+      cmd_autoksyms_h = mkdir -p $(dir $@); \
+			$(CONFIG_SHELL) $(srctree)/scripts/gen_autoksyms.sh $@
+
 $(autoksyms_h):
-	$(Q)mkdir -p $(dir $@)
-	$(Q)touch $@
+	$(call cmd,autoksyms_h)
 
 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
 
@@ -1240,14 +1248,18 @@ ifneq ($(dtstree),)
 	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
 
 PHONY += dtbs dtbs_install dtbs_check
-dtbs dtbs_check: include/config/kernel.release scripts_dtc
+dtbs: include/config/kernel.release scripts_dtc
 	$(Q)$(MAKE) $(build)=$(dtstree)
 
-dtbs_check: export CHECK_DTBS=1
-dtbs_check: dt_binding_check
+ifneq ($(filter dtbs_check, $(MAKECMDGOALS)),)
+export CHECK_DTBS=y
+dtbs: dt_binding_check
+endif
+
+dtbs_check: dtbs
 
 dtbs_install:
-	$(Q)$(MAKE) $(dtbinst)=$(dtstree)
+	$(Q)$(MAKE) $(dtbinst)=$(dtstree) dst=$(INSTALL_DTBS_PATH)
 
 ifdef CONFIG_OF_EARLY_FLATTREE
 all: dtbs
@@ -1259,6 +1271,10 @@ PHONY += scripts_dtc
 scripts_dtc: scripts_basic
 	$(Q)$(MAKE) $(build)=scripts/dtc
 
+ifneq ($(filter dt_binding_check, $(MAKECMDGOALS)),)
+export CHECK_DT_BINDING=y
+endif
+
 PHONY += dt_binding_check
 dt_binding_check: scripts_dtc
 	$(Q)$(MAKE) $(build)=Documentation/devicetree/bindings
@@ -1470,12 +1486,15 @@ help:
 	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'
 	@echo  ''
 	@echo  'Kernel selftest:'
-	@echo  '  kselftest       - Build and run kernel selftest (run as root)'
-	@echo  '                    Build, install, and boot kernel before'
-	@echo  '                    running kselftest on it'
-	@echo  '  kselftest-clean - Remove all generated kselftest files'
-	@echo  '  kselftest-merge - Merge all the config dependencies of kselftest to existing'
-	@echo  '                    .config.'
+	@echo  '  kselftest         - Build and run kernel selftest'
+	@echo  '                      Build, install, and boot kernel before'
+	@echo  '                      running kselftest on it'
+	@echo  '                      Run as root for full coverage'
+	@echo  '  kselftest-all     - Build kernel selftest'
+	@echo  '  kselftest-install - Build and install kernel selftest'
+	@echo  '  kselftest-clean   - Remove all generated kselftest files'
+	@echo  '  kselftest-merge   - Merge all the config dependencies of'
+	@echo  '		      kselftest to existing .config.'
 	@echo  ''
 	@$(if $(dtstree), \
 		echo 'Devicetree:'; \
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 9ece111b0254..b4f0e37b83eb 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -87,11 +87,6 @@ config SUPERH64
 	select HAVE_EXIT_THREAD
 	select KALLSYMS
 
-config ARCH_DEFCONFIG
-	string
-	default "arch/sh/configs/shx3_defconfig" if SUPERH32
-	default "arch/sh/configs/cayman_defconfig" if SUPERH64
-
 config GENERIC_BUG
 	def_bool y
 	depends on BUG && SUPERH32
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 9cc9ab04bd99..da515fdad83d 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -96,11 +96,6 @@ config SPARC64
 	select PCI_DOMAINS if PCI
 	select ARCH_HAS_GIGANTIC_PAGE
 
-config ARCH_DEFCONFIG
-	string
-	default "arch/sparc/configs/sparc32_defconfig" if SPARC32
-	default "arch/sparc/configs/sparc64_defconfig" if SPARC64
-
 config ARCH_PROC_KCORE_TEXT
 	def_bool y
 
diff --git a/arch/sparc/include/asm/string.h b/arch/sparc/include/asm/string.h
index 3d9cd082716b..001a17baf2d5 100644
--- a/arch/sparc/include/asm/string.h
+++ b/arch/sparc/include/asm/string.h
@@ -37,6 +37,10 @@ void *memmove(void *, const void *, __kernel_size_t);
 #define __HAVE_ARCH_MEMCMP
 int memcmp(const void *,const void *,__kernel_size_t);
 
+/* Now the str*() stuff... */
+#define __HAVE_ARCH_STRLEN
+__kernel_size_t strlen(const char *);
+
 #define __HAVE_ARCH_STRNCMP
 int strncmp(const char *, const char *, __kernel_size_t);
 
diff --git a/arch/sparc/include/asm/string_64.h b/arch/sparc/include/asm/string_64.h
index ee9ba67321bd..d5c563058a5b 100644
--- a/arch/sparc/include/asm/string_64.h
+++ b/arch/sparc/include/asm/string_64.h
@@ -12,8 +12,4 @@
 
 #include <asm/asi.h>
 
-/* Now the str*() stuff... */
-#define __HAVE_ARCH_STRLEN
-__kernel_size_t strlen(const char *);
-
 #endif /* !(__SPARC64_STRING_H__) */
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ade80caafe6b..c1e1931f591f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -240,11 +240,6 @@ config OUTPUT_FORMAT
 	default "elf32-i386" if X86_32
 	default "elf64-x86-64" if X86_64
 
-config ARCH_DEFCONFIG
-	string
-	default "arch/x86/configs/i386_defconfig" if X86_32
-	default "arch/x86/configs/x86_64_defconfig" if X86_64
-
 config LOCKDEP_SUPPORT
 	def_bool y
 
diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index a8985e1f7432..95d26a69088b 100644
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -27,11 +27,6 @@ config X86_64
 	def_bool 64BIT
 	select MODULES_USE_ELF_RELA
 
-config ARCH_DEFCONFIG
-	string
-	default "arch/um/configs/i386_defconfig" if X86_32
-	default "arch/um/configs/x86_64_defconfig" if X86_64
-
 config 3_LEVEL_PGTABLES
 	bool "Three-level pagetables" if !64BIT
 	default 64BIT
diff --git a/drivers/net/wan/Kconfig b/drivers/net/wan/Kconfig
index 4530840e15ef..dbc0e3f7a3e2 100644
--- a/drivers/net/wan/Kconfig
+++ b/drivers/net/wan/Kconfig
@@ -200,7 +200,7 @@ config WANXL_BUILD_FIRMWARE
 	depends on WANXL && !PREVENT_FIRMWARE_BUILD
 	help
 	  Allows you to rebuild firmware run by the QUICC processor.
-	  It requires as68k, ld68k and hexdump programs.
+	  It requires m68k toolchains and hexdump programs.
 
 	  You should never need this option, say N.
 
diff --git a/drivers/net/wan/Makefile b/drivers/net/wan/Makefile
index 701f5d2fe3b6..380271a011e4 100644
--- a/drivers/net/wan/Makefile
+++ b/drivers/net/wan/Makefile
@@ -40,21 +40,30 @@ $(obj)/wanxl.o:	$(obj)/wanxlfw.inc
 
 ifeq ($(CONFIG_WANXL_BUILD_FIRMWARE),y)
 ifeq ($(ARCH),m68k)
-  AS68K = $(AS)
-  LD68K = $(LD)
+  M68KCC = $(CC)
+  M68KLD = $(LD)
 else
-  AS68K = as68k
-  LD68K = ld68k
+  M68KCC = $(CROSS_COMPILE_M68K)gcc
+  M68KLD = $(CROSS_COMPILE_M68K)ld
 endif
 
-quiet_cmd_build_wanxlfw = BLD FW  $@
-      cmd_build_wanxlfw = \
-	$(CPP) -D__ASSEMBLY__ -Wp,-MD,$(depfile) -I$(srctree)/include/uapi $< | $(AS68K) -m68360 -o $(obj)/wanxlfw.o; \
-	$(LD68K) --oformat binary -Ttext 0x1000 $(obj)/wanxlfw.o -o $(obj)/wanxlfw.bin; \
-	hexdump -ve '"\n" 16/1 "0x%02X,"' $(obj)/wanxlfw.bin | sed 's/0x  ,//g;1s/^/static const u8 firmware[]={/;$$s/,$$/\n};\n/' >$(obj)/wanxlfw.inc; \
-	rm -f $(obj)/wanxlfw.bin $(obj)/wanxlfw.o
+quiet_cmd_build_wanxlfw = BLDFW   $@
+      cmd_build_wanxlfw = hexdump -ve '"\n" 16/1 "0x%02X,"' $< | \
+	sed 's/0x  ,//g;1s/^/static const u8 firmware[]={/;$$s/,$$/\n};\n/' > $@
 
-$(obj)/wanxlfw.inc:	$(src)/wanxlfw.S
-	$(call if_changed_dep,build_wanxlfw)
-targets += wanxlfw.inc
+$(obj)/wanxlfw.inc: $(obj)/wanxlfw.bin FORCE
+	$(call if_changed,build_wanxlfw)
+
+quiet_cmd_m68kld_bin_o = M68KLD  $@
+      cmd_m68kld_bin_o = $(M68KLD) --oformat binary -Ttext 0x1000 $< -o $@
+
+$(obj)/wanxlfw.bin: $(obj)/wanxlfw.o FORCE
+	$(call if_changed,m68kld_bin_o)
+
+quiet_cmd_m68kas_o_S = M68KAS  $@
+      cmd_m68kas_o_S = $(M68KCC) -D__ASSEMBLY__ -Wp,-MD,$(depfile) -I$(srctree)/include/uapi -c -o $@ $<
+
+$(obj)/wanxlfw.o: $(src)/wanxlfw.S FORCE
+	$(call if_changed_dep,m68kas_o_S)
 endif
+targets += wanxlfw.inc wanxlfw.bin wanxlfw.o
diff --git a/include/net/drop_monitor.h b/include/net/drop_monitor.h
index 2ab668461463..f68bc373544a 100644
--- a/include/net/drop_monitor.h
+++ b/include/net/drop_monitor.h
@@ -19,7 +19,7 @@ struct net_dm_hw_metadata {
 	struct net_device *input_dev;
 };
 
-#if IS_ENABLED(CONFIG_NET_DROP_MONITOR)
+#if IS_REACHABLE(CONFIG_NET_DROP_MONITOR)
 void net_dm_hw_report(struct sk_buff *skb,
 		      const struct net_dm_hw_metadata *hw_metadata);
 #else
diff --git a/init/Kconfig b/init/Kconfig
index 697d109387ed..f11846c06176 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -6,8 +6,7 @@ config DEFCONFIG_LIST
 	default "/lib/modules/$(shell,uname -r)/.config"
 	default "/etc/kernel-config"
 	default "/boot/config-$(shell,uname -r)"
-	default ARCH_DEFCONFIG
-	default "arch/$(ARCH)/defconfig"
+	default "arch/$(SRCARCH)/configs/$(KBUILD_DEFCONFIG)"
 
 config CC_IS_GCC
 	def_bool $(success,$(CC) --version | head -n 1 | grep -q gcc)
@@ -2211,6 +2210,19 @@ config TRIM_UNUSED_KSYMS
 
 	  If unsure, or if you need to build out-of-tree modules, say N.
 
+config UNUSED_KSYMS_WHITELIST
+	string "Whitelist of symbols to keep in ksymtab"
+	depends on TRIM_UNUSED_KSYMS
+	help
+	  By default, all unused exported symbols will be un-exported from the
+	  build when TRIM_UNUSED_KSYMS is selected.
+
+	  UNUSED_KSYMS_WHITELIST allows to whitelist symbols that must be kept
+	  exported at all times, even in absence of in-tree users. The value to
+	  set here is the path to a text file containing the list of symbols,
+	  one per line. The path can be absolute, or relative to the kernel
+	  source tree.
+
 endif # MODULES
 
 config MODULES_TREE_LOOKUP
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 5c315661931e..1ae560370581 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -266,7 +266,7 @@ config ENABLE_MUST_CHECK
 	  attribute warn_unused_result" messages.
 
 config FRAME_WARN
-	int "Warn for stack frames larger than (needs gcc 4.4)"
+	int "Warn for stack frames larger than"
 	range 0 8192
 	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
 	default 1280 if (!64BIT && PARISC)
@@ -276,7 +276,6 @@ config FRAME_WARN
 	  Tell gcc to warn at build time for stack frames larger than this.
 	  Setting this too low will cause a lot of warnings.
 	  Setting it to 0 disables the warning.
-	  Requires gcc 4.4
 
 config STRIP_ASM_SYMS
 	bool "Strip assembler-generated symbols during link"
diff --git a/scripts/Makefile.dtbinst b/scripts/Makefile.dtbinst
index 7301ab5e2e06..50d580d77ae9 100644
--- a/scripts/Makefile.dtbinst
+++ b/scripts/Makefile.dtbinst
@@ -13,28 +13,24 @@ src := $(obj)
 PHONY := __dtbs_install
 __dtbs_install:
 
-export dtbinst_root ?= $(obj)
-
 include include/config/auto.conf
 include scripts/Kbuild.include
 include $(src)/Makefile
 
-dtbinst-files	:= $(sort $(dtb-y) $(if $(CONFIG_OF_ALL_DTBS), $(dtb-)))
-dtbinst-dirs	:= $(subdir-y) $(subdir-m)
-
-# Helper targets for Installing DTBs into the boot directory
-quiet_cmd_dtb_install =	INSTALL $<
-      cmd_dtb_install =	mkdir -p $(2); cp $< $(2)
+dtbs    := $(addprefix $(dst)/, $(dtb-y) $(if $(CONFIG_OF_ALL_DTBS),$(dtb-)))
+subdirs := $(addprefix $(obj)/, $(subdir-y) $(subdir-m))
 
-install-dir = $(patsubst $(dtbinst_root)%,$(INSTALL_DTBS_PATH)%,$(obj))
+__dtbs_install: $(dtbs) $(subdirs)
+	@:
 
-$(dtbinst-files): %.dtb: $(obj)/%.dtb
-	$(call cmd,dtb_install,$(install-dir))
+quiet_cmd_dtb_install = INSTALL $@
+      cmd_dtb_install = install -D $< $@
 
-$(dtbinst-dirs):
-	$(Q)$(MAKE) $(dtbinst)=$(obj)/$@
+$(dst)/%.dtb: $(obj)/%.dtb
+	$(call cmd,dtb_install)
 
-PHONY += $(dtbinst-files) $(dtbinst-dirs)
-__dtbs_install: $(dtbinst-files) $(dtbinst-dirs)
+PHONY += $(subdirs)
+$(subdirs):
+	$(Q)$(MAKE) $(dtbinst)=$@ dst=$(patsubst $(obj)/%,$(dst)/%,$@)
 
 .PHONY: $(PHONY)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 752ff0a225a9..97547108ee7f 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -297,7 +297,8 @@ $(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
 
 DT_CHECKER ?= dt-validate
 DT_BINDING_DIR := Documentation/devicetree/bindings
-DT_TMP_SCHEMA := $(objtree)/$(DT_BINDING_DIR)/processed-schema.yaml
+# DT_TMP_SCHEMA may be overridden from Documentation/devicetree/bindings/Makefile
+DT_TMP_SCHEMA ?= $(objtree)/$(DT_BINDING_DIR)/processed-schema.yaml
 
 quiet_cmd_dtb_check =	CHECK   $@
       cmd_dtb_check =	$(DT_CHECKER) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index b4d3f2d122ac..957eed6a17a5 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -46,13 +46,14 @@ include scripts/Kbuild.include
 kernelsymfile := $(objtree)/Module.symvers
 modulesymfile := $(firstword $(KBUILD_EXTMOD))/Module.symvers
 
-MODPOST = scripts/mod/modpost						\
-	$(if $(CONFIG_MODVERSIONS),-m)					\
-	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)			\
-	$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile)			\
-	$(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS)))	\
-	$(if $(KBUILD_EXTMOD),-o $(modulesymfile))			\
-	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)			\
+MODPOST = scripts/mod/modpost								\
+	$(if $(CONFIG_MODVERSIONS),-m)							\
+	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)					\
+	$(if $(KBUILD_EXTMOD),-i,-o) $(kernelsymfile)					\
+	$(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS)))			\
+	$(if $(KBUILD_EXTMOD),-o $(modulesymfile))					\
+	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)					\
+	$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N) 	\
 	$(if $(KBUILD_MODPOST_WARN),-w)
 
 ifdef MODPOST_VMLINUX
diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
index a904bf1f5e67..2b366d945ccb 100755
--- a/scripts/adjust_autoksyms.sh
+++ b/scripts/adjust_autoksyms.sh
@@ -1,14 +1,13 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0-only
 
-# Script to create/update include/generated/autoksyms.h and dependency files
+# Script to update include/generated/autoksyms.h and dependency files
 #
 # Copyright:	(C) 2016  Linaro Limited
 # Created by:	Nicolas Pitre, January 2016
 #
 
-# Create/update the include/generated/autoksyms.h file from the list
-# of all module's needed symbols as recorded on the second line of *.mod files.
+# Update the include/generated/autoksyms.h file.
 #
 # For each symbol being added or removed, the corresponding dependency
 # file's timestamp is updated to force a rebuild of the affected source
@@ -38,23 +37,8 @@ esac
 # We need access to CONFIG_ symbols
 . include/config/auto.conf
 
-# Generate a new ksym list file with symbols needed by the current
-# set of modules.
-cat > "$new_ksyms_file" << EOT
-/*
- * Automatically generated file; DO NOT EDIT.
- */
-
-EOT
-sed 's/ko$/mod/' modules.order |
-xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |
-sort -u |
-sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$new_ksyms_file"
-
-# Special case for modversions (see modpost.c)
-if [ -n "$CONFIG_MODVERSIONS" ]; then
-	echo "#define __KSYM_module_layout 1" >> "$new_ksyms_file"
-fi
+# Generate a new symbol list file
+$CONFIG_SHELL $srctree/scripts/gen_autoksyms.sh "$new_ksyms_file"
 
 # Extract changes between old and new list and touch corresponding
 # dependency files.
diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
index 9ba47b0a47b9..877ca2c88246 100644
--- a/scripts/basic/fixdep.c
+++ b/scripts/basic/fixdep.c
@@ -77,11 +77,6 @@
  * dependencies on include/config/my/option.h for every
  * CONFIG_MY_OPTION encountered in any of the prerequisites.
  *
- * It will also filter out all the dependencies on *.ver. We need
- * to make sure that the generated version checksum are globally up
- * to date before even starting the recursive build, so it's too late
- * at this point anyway.
- *
  * We don't even try to really parse the header files, but
  * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will
  * be picked up as well. It's not a problem with respect to
@@ -251,7 +246,7 @@ static void parse_config_file(const char *p)
 		}
 		p += 7;
 		q = p;
-		while (*q && (isalnum(*q) || *q == '_'))
+		while (isalnum(*q) || *q == '_')
 			q++;
 		if (str_ends_with(p, q - p, "_MODULE"))
 			r = q - 7;
@@ -299,8 +294,7 @@ static void *read_file(const char *filename)
 static int is_ignored_file(const char *s, int len)
 {
 	return str_ends_with(s, len, "include/generated/autoconf.h") ||
-	       str_ends_with(s, len, "include/generated/autoksyms.h") ||
-	       str_ends_with(s, len, ".ver");
+	       str_ends_with(s, len, "include/generated/autoksyms.h");
 }
 
 /*
diff --git a/scripts/dtc/Makefile b/scripts/dtc/Makefile
index 3acbb410904c..2f3c3a7e1620 100644
--- a/scripts/dtc/Makefile
+++ b/scripts/dtc/Makefile
@@ -1,8 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0
 # scripts/dtc makefile
 
-hostprogs		:= dtc
-always-$(CONFIG_DTC)	:= $(hostprogs)
+hostprogs			:= dtc
+always-$(CONFIG_DTC)		+= $(hostprogs)
+always-$(CHECK_DT_BINDING)	+= $(hostprogs)
 
 dtc-objs	:= dtc.o flattree.o fstree.o data.o livetree.o treesource.o \
 		   srcpos.o checks.o util.o
diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
index f2ee8bd7abc6..efff00959a9c 100644
--- a/scripts/gcc-plugins/Makefile
+++ b/scripts/gcc-plugins/Makefile
@@ -10,7 +10,7 @@ else
   HOSTLIBS := hostcxxlibs
   HOST_EXTRACXXFLAGS += -I$(GCC_PLUGINS_DIR)/include -I$(src) -std=gnu++98 -fno-rtti
   HOST_EXTRACXXFLAGS += -fno-exceptions -fasynchronous-unwind-tables -ggdb
-  HOST_EXTRACXXFLAGS += -Wno-narrowing -Wno-unused-variable
+  HOST_EXTRACXXFLAGS += -Wno-narrowing -Wno-unused-variable -Wno-c++11-compat
   export HOST_EXTRACXXFLAGS
 endif
 
diff --git a/scripts/gen_autoksyms.sh b/scripts/gen_autoksyms.sh
new file mode 100755
index 000000000000..16c0b2ddaa4c
--- /dev/null
+++ b/scripts/gen_autoksyms.sh
@@ -0,0 +1,52 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Create an autoksyms.h header file from the list of all module's needed symbols
+# as recorded on the second line of *.mod files and the user-provided symbol
+# whitelist.
+
+set -e
+
+output_file="$1"
+
+# Use "make V=1" to debug this script.
+case "$KBUILD_VERBOSE" in
+*1*)
+	set -x
+	;;
+esac
+
+# We need access to CONFIG_ symbols
+. include/config/auto.conf
+
+ksym_wl=/dev/null
+if [ -n "$CONFIG_UNUSED_KSYMS_WHITELIST" ]; then
+	# Use 'eval' to expand the whitelist path and check if it is relative
+	eval ksym_wl="$CONFIG_UNUSED_KSYMS_WHITELIST"
+	[ "${ksym_wl}" != "${ksym_wl#/}" ] || ksym_wl="$abs_srctree/$ksym_wl"
+	if [ ! -f "$ksym_wl" ] || [ ! -r "$ksym_wl" ]; then
+		echo "ERROR: '$ksym_wl' whitelist file not found" >&2
+		exit 1
+	fi
+fi
+
+# Generate a new ksym list file with symbols needed by the current
+# set of modules.
+cat > "$output_file" << EOT
+/*
+ * Automatically generated file; DO NOT EDIT.
+ */
+
+EOT
+
+[ -f modules.order ] && modlist=modules.order || modlist=/dev/null
+sed 's/ko$/mod/' $modlist |
+xargs -n1 sed -n -e '2{s/ /\n/g;/^$/!p;}' -- |
+cat - "$ksym_wl" |
+sort -u |
+sed -e 's/\(.*\)/#define __KSYM_\1 1/' >> "$output_file"
+
+# Special case for modversions (see modpost.c)
+if [ -n "$CONFIG_MODVERSIONS" ]; then
+	echo "#define __KSYM_module_layout 1" >> "$output_file"
+fi
diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index 5887ceb6229e..c9d0a4a8efb3 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -12,10 +12,6 @@ else
 Kconfig := Kconfig
 endif
 
-ifndef KBUILD_DEFCONFIG
-KBUILD_DEFCONFIG := defconfig
-endif
-
 ifeq ($(quiet),silent_)
 silent := -s
 endif
diff --git a/scripts/kconfig/qconf.cc b/scripts/kconfig/qconf.cc
index 82773cc35d35..50a5245d87bb 100644
--- a/scripts/kconfig/qconf.cc
+++ b/scripts/kconfig/qconf.cc
@@ -309,8 +309,6 @@ ConfigList::ConfigList(ConfigView* p, const char *name)
 	  showName(false), showRange(false), showData(false), mode(singleMode), optMode(normalOpt),
 	  rootEntry(0), headerPopup(0)
 {
-	int i;
-
 	setObjectName(name);
 	setSortingEnabled(false);
 	setRootIsDecorated(true);
diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 8d38b700b314..3dc81397d003 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -221,7 +221,7 @@ static void sym_calc_visibility(struct symbol *sym)
 		sym_set_changed(sym);
 	}
 	tri = no;
-	if (sym->implied.expr && sym->dir_dep.tri != no)
+	if (sym->implied.expr)
 		tri = expr_calc_value(sym->implied.expr);
 	if (tri == mod && sym_get_type(sym) == S_BOOLEAN)
 		tri = yes;
@@ -394,6 +394,8 @@ void sym_calc_value(struct symbol *sym)
 				if (sym->implied.tri != no) {
 					sym->flags |= SYMBOL_WRITE;
 					newval.tri = EXPR_OR(newval.tri, sym->implied.tri);
+					newval.tri = EXPR_AND(newval.tri,
+							      sym->dir_dep.tri);
 				}
 			}
 		calc_newval:
@@ -401,8 +403,7 @@ void sym_calc_value(struct symbol *sym)
 				sym_warn_unmet_dep(sym);
 			newval.tri = EXPR_OR(newval.tri, sym->rev_dep.tri);
 		}
-		if (newval.tri == mod &&
-		    (sym_get_type(sym) == S_BOOLEAN || sym->implied.tri == yes))
+		if (newval.tri == mod && sym_get_type(sym) == S_BOOLEAN)
 			newval.tri = yes;
 		break;
 	case S_STRING:
@@ -484,8 +485,6 @@ bool sym_tristate_within_range(struct symbol *sym, tristate val)
 		return false;
 	if (sym->visible <= sym->rev_dep.tri)
 		return false;
-	if (sym->implied.tri == yes && val == mod)
-		return false;
 	if (sym_is_choice_value(sym) && sym->visible == yes)
 		return val == yes;
 	return val >= sym->rev_dep.tri && val <= sym->visible;
diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h
index 3a5a4b210c86..3ff26e5b2eac 100755
--- a/scripts/mkcompile_h
+++ b/scripts/mkcompile_h
@@ -10,17 +10,6 @@ CC=$6
 
 vecho() { [ "${quiet}" = "silent_" ] || echo "$@" ; }
 
-# If compile.h exists already and we don't own autoconf.h
-# (i.e. we're not the same user who did make *config), don't
-# modify compile.h
-# So "sudo make install" won't change the "compiled by <user>"
-# do "compiled by root"
-
-if [ -r $TARGET -a ! -O include/generated/autoconf.h ]; then
-  vecho "  SKIPPED $TARGET"
-  exit 0
-fi
-
 # Do not expand names
 set -f
 
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index acf0a69d68ce..5c3c50c5ec52 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -39,6 +39,8 @@ static int sec_mismatch_count = 0;
 static int sec_mismatch_fatal = 0;
 /* ignore missing files */
 static int ignore_missing_files;
+/* If set to 1, only warn (instead of error) about missing ns imports */
+static int allow_missing_ns_imports;
 
 enum export {
 	export_plain,      export_unused,     export_gpl,
@@ -51,41 +53,33 @@ enum export {
 
 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
 
-#define PRINTF __attribute__ ((format (printf, 1, 2)))
-
-PRINTF void fatal(const char *fmt, ...)
+void __attribute__((format(printf, 2, 3)))
+modpost_log(enum loglevel loglevel, const char *fmt, ...)
 {
 	va_list arglist;
 
-	fprintf(stderr, "FATAL: ");
-
-	va_start(arglist, fmt);
-	vfprintf(stderr, fmt, arglist);
-	va_end(arglist);
-
-	exit(1);
-}
-
-PRINTF void warn(const char *fmt, ...)
-{
-	va_list arglist;
+	switch (loglevel) {
+	case LOG_WARN:
+		fprintf(stderr, "WARNING: ");
+		break;
+	case LOG_ERROR:
+		fprintf(stderr, "ERROR: ");
+		break;
+	case LOG_FATAL:
+		fprintf(stderr, "FATAL: ");
+		break;
+	default: /* invalid loglevel, ignore */
+		break;
+	}
 
-	fprintf(stderr, "WARNING: ");
+	fprintf(stderr, "modpost: ");
 
 	va_start(arglist, fmt);
 	vfprintf(stderr, fmt, arglist);
 	va_end(arglist);
-}
-
-PRINTF void merror(const char *fmt, ...)
-{
-	va_list arglist;
 
-	fprintf(stderr, "ERROR: ");
-
-	va_start(arglist, fmt);
-	vfprintf(stderr, fmt, arglist);
-	va_end(arglist);
+	if (loglevel == LOG_FATAL)
+		exit(1);
 }
 
 static inline bool strends(const char *str, const char *postfix)
@@ -113,7 +107,7 @@ static int is_vmlinux(const char *modname)
 void *do_nofail(void *ptr, const char *expr)
 {
 	if (!ptr)
-		fatal("modpost: Memory allocation failure: %s.\n", expr);
+		fatal("Memory allocation failure: %s.\n", expr);
 
 	return ptr;
 }
@@ -2022,7 +2016,7 @@ static void read_symbols(const char *modname)
 
 	license = get_modinfo(&info, "license");
 	if (!license && !is_vmlinux(modname))
-		warn("modpost: missing MODULE_LICENSE() in %s\n"
+		warn("missing MODULE_LICENSE() in %s\n"
 		     "see include/linux/module.h for "
 		     "more information\n", modname);
 	while (license) {
@@ -2153,15 +2147,15 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
 
 	switch (exp) {
 	case export_gpl:
-		fatal("modpost: GPL-incompatible module %s%s "
+		fatal("GPL-incompatible module %s%s "
 		      "uses GPL-only symbol '%s'\n", m, e, s);
 		break;
 	case export_unused_gpl:
-		fatal("modpost: GPL-incompatible module %s%s "
+		fatal("GPL-incompatible module %s%s "
 		      "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
 		break;
 	case export_gpl_future:
-		warn("modpost: GPL-incompatible module %s%s "
+		warn("GPL-incompatible module %s%s "
 		      "uses future GPL-only symbol '%s'\n", m, e, s);
 		break;
 	case export_plain:
@@ -2179,7 +2173,7 @@ static void check_for_unused(enum export exp, const char *m, const char *s)
 	switch (exp) {
 	case export_unused:
 	case export_unused_gpl:
-		warn("modpost: module %s%s "
+		warn("module %s%s "
 		      "uses symbol '%s' marked UNUSED\n", m, e, s);
 		break;
 	default:
@@ -2198,14 +2192,11 @@ static int check_exports(struct module *mod)
 		exp = find_symbol(s->name);
 		if (!exp || exp->module == mod) {
 			if (have_vmlinux && !s->weak) {
-				if (warn_unresolved) {
-					warn("\"%s\" [%s.ko] undefined!\n",
-					     s->name, mod->name);
-				} else {
-					merror("\"%s\" [%s.ko] undefined!\n",
-					       s->name, mod->name);
+				modpost_log(warn_unresolved ? LOG_WARN : LOG_ERROR,
+					    "\"%s\" [%s.ko] undefined!\n",
+					    s->name, mod->name);
+				if (!warn_unresolved)
 					err = 1;
-				}
 			}
 			continue;
 		}
@@ -2217,8 +2208,11 @@ static int check_exports(struct module *mod)
 
 		if (exp->namespace &&
 		    !module_imports_namespace(mod, exp->namespace)) {
-			warn("module %s uses symbol %s from namespace %s, but does not import it.\n",
-			     basename, exp->name, exp->namespace);
+			modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
+				    "module %s uses symbol %s from namespace %s, but does not import it.\n",
+				    basename, exp->name, exp->namespace);
+			if (!allow_missing_ns_imports)
+				err = 1;
 			add_namespace(&mod->missing_namespaces, exp->namespace);
 		}
 
@@ -2565,7 +2559,7 @@ int main(int argc, char **argv)
 	struct ext_sym_list *extsym_iter;
 	struct ext_sym_list *extsym_start = NULL;
 
-	while ((opt = getopt(argc, argv, "i:e:mnsT:o:awEd:")) != -1) {
+	while ((opt = getopt(argc, argv, "i:e:mnsT:o:awENd:")) != -1) {
 		switch (opt) {
 		case 'i':
 			kernel_read = optarg;
@@ -2603,6 +2597,9 @@ int main(int argc, char **argv)
 		case 'E':
 			sec_mismatch_fatal = 1;
 			break;
+		case 'N':
+			allow_missing_ns_imports = 1;
+			break;
 		case 'd':
 			missing_namespace_deps = optarg;
 			break;
@@ -2658,7 +2655,7 @@ int main(int argc, char **argv)
 	if (dump_write)
 		write_dump(dump_write);
 	if (sec_mismatch_count && sec_mismatch_fatal)
-		fatal("modpost: Section mismatches detected.\n"
+		fatal("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;
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 64a82d2d85f6..60dca9b7106b 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -198,6 +198,14 @@ void *grab_file(const char *filename, unsigned long *size);
 char* get_next_line(unsigned long *pos, void *file, unsigned long size);
 void release_file(void *file, unsigned long size);
 
-void fatal(const char *fmt, ...);
-void warn(const char *fmt, ...);
-void merror(const char *fmt, ...);
+enum loglevel {
+	LOG_WARN,
+	LOG_ERROR,
+	LOG_FATAL
+};
+
+void modpost_log(enum loglevel loglevel, const char *fmt, ...);
+
+#define warn(fmt, args...)	modpost_log(LOG_WARN, fmt, ##args)
+#define merror(fmt, args...)	modpost_log(LOG_ERROR, fmt, ##args)
+#define fatal(fmt, args...)	modpost_log(LOG_FATAL, fmt, ##args)
diff --git a/scripts/package/mkdebian b/scripts/package/mkdebian
index 357dc56bcf30..df1adbfb8ead 100755
--- a/scripts/package/mkdebian
+++ b/scripts/package/mkdebian
@@ -198,6 +198,10 @@ Description: Linux support headers for userspace development
  This package provides userspaces headers from the Linux kernel.  These headers
  are used by the installed headers for GNU glibc and other system libraries.
 Multi-Arch: same
+EOF
+
+if is_enabled CONFIG_DEBUG_INFO; then
+cat <<EOF >> debian/control
 
 Package: $dbg_packagename
 Section: debug
@@ -206,6 +210,7 @@ Description: Linux kernel debugging symbols for $version
  This package will come in handy if you need to debug the kernel. It provides
  all the necessary debug symbols for the kernel and its modules.
 EOF
+fi
 
 cat <<EOF > debian/rules
 #!$(command -v $MAKE) -f