diff --git a/Makefile b/Makefile
index 3c976a69ca2b..67e96818a79a 100644
--- a/Makefile
+++ b/Makefile
@@ -377,6 +377,7 @@ endif
 # Make variables (CC, etc...)
 AS		= $(CROSS_COMPILE)as
 LD		= $(CROSS_COMPILE)ld
+LDGOLD		= $(CROSS_COMPILE)ld.gold
 CC		= $(CROSS_COMPILE)gcc
 CPP		= $(CC) -E
 AR		= $(CROSS_COMPILE)ar
@@ -636,6 +637,20 @@ CFLAGS_GCOV	:= -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disabl
 CFLAGS_KCOV	:= $(call cc-option,-fsanitize-coverage=trace-pc,)
 export CFLAGS_GCOV CFLAGS_KCOV
 
+# Make toolchain changes before including arch/$(SRCARCH)/Makefile to ensure
+# ar/cc/ld-* macros return correct values.
+ifdef CONFIG_LTO_CLANG
+# use GNU gold with LLVMgold for LTO linking, and LD for vmlinux_link
+LDFINAL_vmlinux := $(LD)
+LD		:= $(LDGOLD)
+LDFLAGS		+= -plugin LLVMgold.so
+# use llvm-ar for building symbol tables from IR files, and llvm-dis instead
+# of objdump for processing symbol versions and exports
+LLVM_AR		:= llvm-ar
+LLVM_DIS	:= llvm-dis
+export LLVM_AR LLVM_DIS
+endif
+
 # The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
 # values of the respective KBUILD_* variables
 ARCH_CPPFLAGS :=
@@ -794,6 +809,26 @@ KBUILD_CFLAGS	+= $(call cc-option,-ffunction-sections,)
 KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
 endif
 
+ifdef CONFIG_LTO_CLANG
+lto-clang-flags	:= -flto -fvisibility=hidden
+
+# allow disabling only clang LTO where needed
+DISABLE_LTO_CLANG := -fno-lto -fvisibility=default
+export DISABLE_LTO_CLANG
+endif
+
+ifdef CONFIG_LTO
+lto-flags	:= $(lto-clang-flags)
+KBUILD_CFLAGS	+= $(lto-flags)
+
+DISABLE_LTO	:= $(DISABLE_LTO_CLANG)
+export DISABLE_LTO
+
+# LDFINAL_vmlinux and LDFLAGS_FINAL_vmlinux can be set to override
+# the linker and flags for vmlinux_link.
+export LDFINAL_vmlinux LDFLAGS_FINAL_vmlinux
+endif
+
 # arch Makefile may override CC so keep this after arch Makefile is included
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 CHECKFLAGS     += $(NOSTDINC_FLAGS)
@@ -1111,6 +1146,22 @@ prepare-objtool: $(objtool_target)
 # CC_STACKPROTECTOR_STRONG! Why did it build with _REGULAR?!")
 PHONY += prepare-compiler-check
 prepare-compiler-check: FORCE
+# Make sure we're using a supported toolchain with LTO_CLANG
+ifdef CONFIG_LTO_CLANG
+  ifneq ($(call clang-ifversion, -ge, 0500, y), y)
+	@echo Cannot use CONFIG_LTO_CLANG: requires clang 5.0 or later >&2 && exit 1
+  endif
+  ifneq ($(call gold-ifversion, -ge, 112000000, y), y)
+	@echo Cannot use CONFIG_LTO_CLANG: requires GNU gold 1.12 or later >&2 && exit 1
+  endif
+endif
+# Make sure compiler supports LTO flags
+ifdef lto-flags
+  ifeq ($(call cc-option, $(lto-flags)),)
+	@echo Cannot use CONFIG_LTO: $(lto-flags) not supported by compiler \
+		>&2 && exit 1
+  endif
+endif
 # Make sure compiler supports requested stack protector flag.
 ifdef stackp-name
   ifeq ($(call cc-option, $(stackp-flag)),)
@@ -1584,7 +1635,8 @@ clean: $(clean-dirs)
 		-o -name modules.builtin -o -name '.tmp_*.o.*' \
 		-o -name '*.c.[012]*.*' \
 		-o -name '*.ll' \
-		-o -name '*.gcno' \) -type f -print | xargs rm -f
+		-o -name '*.gcno' \
+		-o -name '*.*.symversions' \) -type f -print | xargs rm -f
 
 # Generate tags for editors
 # ---------------------------------------------------------------------------
diff --git a/arch/Kconfig b/arch/Kconfig
index 400b9e1b2f27..e59db803807f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -605,6 +605,46 @@ config LD_DEAD_CODE_DATA_ELIMINATION
 	  sections (e.g., '.text.init'). Typically '.' in section names
 	  is used to distinguish them from label names / C identifiers.
 
+config LTO
+	def_bool n
+
+config ARCH_SUPPORTS_LTO_CLANG
+	bool
+	help
+	  An architecture should select this option it supports:
+	  - compiling with clang,
+	  - compiling inline assembly with clang's integrated assembler,
+	  - and linking with either lld or GNU gold w/ LLVMgold.
+
+choice
+	prompt "Link-Time Optimization (LTO) (EXPERIMENTAL)"
+	default LTO_NONE
+	help
+	  This option turns on Link-Time Optimization (LTO).
+
+config LTO_NONE
+	bool "None"
+
+config LTO_CLANG
+	bool "Use clang Link Time Optimization (LTO) (EXPERIMENTAL)"
+	depends on ARCH_SUPPORTS_LTO_CLANG
+	depends on !FTRACE_MCOUNT_RECORD
+	select LTO
+	select THIN_ARCHIVES
+	select LD_DEAD_CODE_DATA_ELIMINATION
+	help
+          This option enables clang's Link Time Optimization (LTO), which allows
+          the compiler to optimize the kernel globally at link time. If you
+          enable this option, the compiler generates LLVM IR instead of object
+          files, and the actual compilation from IR occurs at the LTO link step,
+          which may take several minutes.
+
+          If you select this option, you must compile the kernel with clang >=
+          5.0 (make CC=clang) and GNU gold from binutils >= 2.27, and have the
+          LLVMgold plug-in in LD_LIBRARY_PATH.
+
+endchoice
+
 config HAVE_ARCH_WITHIN_STACK_FRAMES
 	bool
 	help
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 7143da06d702..bda756f438f1 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -210,6 +210,23 @@ else
 
 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
 
+ifdef CONFIG_LTO_CLANG
+# Generate .o.symversions files for each .o with exported symbols, and link these
+# to the kernel and/or modules at the end.
+cmd_modversions_c =								\
+	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) >/dev/null 2>/dev/null; then		\
+		if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then	\
+			$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
+			    > $(@D)/$(@F).symversions;				\
+		fi;								\
+	else									\
+		if $(LLVM_DIS) -o=- $(@D)/.tmp_$(@F) | grep -q __ksymtab; then	\
+			$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
+			    > $(@D)/$(@F).symversions;				\
+		fi;								\
+	fi;									\
+	mv -f $(@D)/.tmp_$(@F) $@;
+else
 cmd_modversions_c =								\
 	if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then		\
 		$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
@@ -222,6 +239,7 @@ cmd_modversions_c =								\
 		mv -f $(@D)/.tmp_$(@F) $@;					\
 	fi;
 endif
+endif
 
 ifdef CONFIG_FTRACE_MCOUNT_RECORD
 ifdef BUILD_C_RECORDMCOUNT
@@ -462,8 +480,29 @@ $(sort $(subdir-obj-y)): $(subdir-ym) ;
 #
 ifdef builtin-target
 
+ifdef CONFIG_LTO_CLANG
+  ifdef CONFIG_MODVERSIONS
+    # combine symversions for later processing
+    update_lto_symversions =				\
+	rm -f $@.symversions; 				\
+	for i in $(filter-out FORCE,$^); do		\
+		if [ -f $$i.symversions ]; then		\
+			cat $$i.symversions 		\
+				>> $@.symversions;	\
+		fi;					\
+	done;
+  endif
+  # rebuild the symbol table with llvm-ar to include IR files
+  update_lto_symtable = ;				\
+	mv -f $@ $@.tmp;				\
+	$(LLVM_AR) rcsT$(KBUILD_ARFLAGS) $@ 		\
+		$$($(AR) t $@.tmp); 			\
+	rm -f $@.tmp
+endif
+
 ifdef CONFIG_THIN_ARCHIVES
-  cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
+  cmd_make_builtin = $(update_lto_symversions)	\
+	rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
   cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
   quiet_cmd_link_o_target = AR      $@
 else
@@ -504,7 +543,11 @@ ifdef lib-target
 quiet_cmd_link_l_target = AR      $@
 
 ifdef CONFIG_THIN_ARCHIVES
-  cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
+  cmd_link_l_target = 					\
+	$(update_lto_symversions)			\
+	rm -f $@; 					\
+	$(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)	\
+	$(update_lto_symtable)
 else
   cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
 endif
@@ -522,14 +565,36 @@ else
 ref_prefix = EXTERN(
 endif
 
-quiet_cmd_export_list = EXPORTS $@
-cmd_export_list = $(OBJDUMP) -h $< | \
-	sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/$(ref_prefix)\1)/p' >$(ksyms-lds);\
-	rm -f $(dummy-object);\
+filter_export_list = sed -ne '/___ksymtab/s/.*+\([^ "]*\).*/$(ref_prefix)\1)/p'
+link_export_list = rm -f $(dummy-object);\
 	echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
 	$(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
 	rm $(dummy-object) $(ksyms-lds)
 
+quiet_cmd_export_list = EXPORTS $@
+
+ifdef CONFIG_LTO_CLANG
+# objdump doesn't understand IR files and llvm-dis doesn't support archives,
+# so we'll walk through each file in the archive separately
+cmd_export_list = 					\
+	rm -f $(ksyms-lds);				\
+	for o in $$($(AR) t $<); do			\
+		if $(OBJDUMP) -h $$o >/dev/null 2>/dev/null; then \
+			$(OBJDUMP) -h $$o | 		\
+				$(filter_export_list) 	\
+				>>$(ksyms-lds);		\
+		else					\
+			$(LLVM_DIS) -o=- $$o |		\
+				$(filter_export_list) 	\
+				>>$(ksyms-lds);		\
+		fi; 					\
+	done;						\
+	$(link_export_list)
+else
+cmd_export_list = $(OBJDUMP) -h $< | $(filter_export_list) >$(ksyms-lds); \
+	$(link_export_list)
+endif
+
 $(obj)/lib-ksyms.o: $(lib-target) FORCE
 	$(call if_changed,export_list)
 
@@ -557,23 +622,32 @@ cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secana
 
 ifdef CONFIG_THIN_ARCHIVES
   quiet_cmd_link_multi-y = AR      $@
-  cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
+  cmd_link_multi-y = $(update_lto_symversions) \
+	rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps) \
+	$(update_lto_symtable)
 else
   quiet_cmd_link_multi-y = LD      $@
   cmd_link_multi-y = $(cmd_link_multi-link)
 endif
 
 quiet_cmd_link_multi-m = LD [M]  $@
-cmd_link_multi-m = $(cmd_link_multi-link)
+
+ifdef CONFIG_LTO_CLANG
+  # don't compile IR until needed
+  cmd_link_multi-m = $(cmd_link_multi-y)
+else
+  cmd_link_multi-m = $(cmd_link_multi-link)
+endif
 
 $(multi-used-y): FORCE
 	$(call if_changed,link_multi-y)
-$(call multi_depend, $(multi-used-y), .o, -objs -y)
 
 $(multi-used-m): FORCE
 	$(call if_changed,link_multi-m)
 	@{ echo $(@:.o=.ko); echo $(link_multi_deps); \
 	   $(cmd_undef_syms); } > $(MODVERDIR)/$(@F:.o=.mod)
+
+$(call multi_depend, $(multi-used-y), .o, -objs -y)
 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
 
 targets += $(multi-used-y) $(multi-used-m)
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 991db7d6e4df..c86c99b4a1cf 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -83,12 +83,28 @@ modpost = scripts/mod/modpost                    \
 
 MODPOST_OPT=$(subst -i,-n,$(filter -i,$(MAKEFLAGS)))
 
+# If CONFIG_LTO_CLANG is enabled, .o files are either LLVM IR, or empty, so we
+# need to link them into actual objects before passing them to modpost
+modpost-ext = $(if $(CONFIG_LTO_CLANG),.lto,)
+
+ifdef CONFIG_LTO_CLANG
+quiet_cmd_cc_lto_link_modules = LD [M]  $@
+cmd_cc_lto_link_modules =						\
+	$(LD) $(ld_flags) -r -o $(@)					\
+		$(shell [ -s $(@:$(modpost-ext).o=.o.symversions) ] &&	\
+			echo -T $(@:$(modpost-ext).o=.o.symversions))	\
+		--whole-archive $(filter-out FORCE,$^)
+
+$(modules:.ko=$(modpost-ext).o): %$(modpost-ext).o: %.o FORCE
+	$(call if_changed,cc_lto_link_modules)
+endif
+
 # We can go over command line length here, so be careful.
 quiet_cmd_modpost = MODPOST $(words $(filter-out vmlinux FORCE, $^)) modules
-      cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/.o/' | $(modpost) $(MODPOST_OPT) -s -T -
+      cmd_modpost = $(MODLISTCMD) | sed 's/\.ko$$/$(modpost-ext)\.o/' | $(modpost) $(MODPOST_OPT) -s -T -
 
 PHONY += __modpost
-__modpost: $(modules:.ko=.o) FORCE
+__modpost: $(modules:.ko=$(modpost-ext).o) FORCE
 	$(call cmd,modpost) $(wildcard vmlinux)
 
 quiet_cmd_kernel-mod = MODPOST $@
@@ -98,8 +114,7 @@ vmlinux.o: FORCE
 	$(call cmd,kernel-mod)
 
 # Declare generated files as targets for modpost
-$(modules:.ko=.mod.c): __modpost ;
-
+$(modules:.ko=$(modpost-ext).mod.c): __modpost ;
 
 # Step 5), compile all *.mod.c files
 
@@ -110,22 +125,33 @@ quiet_cmd_cc_o_c = CC      $@
       cmd_cc_o_c = $(CC) $(c_flags) $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE) \
 		   -c -o $@ $<
 
-$(modules:.ko=.mod.o): %.mod.o: %.mod.c FORCE
+$(modules:.ko=.mod.o): %.mod.o: %$(modpost-ext).mod.c FORCE
 	$(call if_changed_dep,cc_o_c)
 
-targets += $(modules:.ko=.mod.o)
+targets += $(modules:.ko=$(modpost-ext).mod.o)
 
 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
 
 # Step 6), final link of the modules with optional arch pass after final link
 quiet_cmd_ld_ko_o = LD [M]  $@
+
+ifdef CONFIG_LTO_CLANG
+      cmd_ld_ko_o = 							\
+	$(LD) -r $(LDFLAGS)                                 		\
+		 $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) 		\
+		 $(shell [ -s $(@:.ko=.o.symversions) ] &&		\
+			echo -T $(@:.ko=.o.symversions))  		\
+		 -o $@ --whole-archive					\
+		 $(filter-out FORCE,$(^:$(modpost-ext).o=.o))
+else
       cmd_ld_ko_o =                                                     \
 	$(LD) -r $(LDFLAGS)                                             \
                  $(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE)             \
                  -o $@ $(filter-out FORCE,$^) ;                         \
 	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
+endif
 
-$(modules): %.ko :%.o %.mod.o FORCE
+$(modules): %.ko: %$(modpost-ext).o %.mod.o FORCE
 	+$(call if_changed,ld_ko_o)
 
 targets += $(modules)
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index e6818b8e7141..ece268ceaaa1 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -61,7 +61,38 @@ archive_builtin()
 		${AR} rcsTP${KBUILD_ARFLAGS} built-in.o			\
 					${KBUILD_VMLINUX_INIT}		\
 					${KBUILD_VMLINUX_MAIN}
+
+		if [ -n "${CONFIG_LTO_CLANG}" ]; then
+			mv -f built-in.o built-in.o.tmp
+			${LLVM_AR} rcsT${KBUILD_ARFLAGS} built-in.o $(${AR} t built-in.o.tmp)
+			rm -f built-in.o.tmp
+		fi
+	fi
+}
+
+# If CONFIG_LTO_CLANG is selected, collect generated symbol versions into
+# .tmp_symversions
+modversions()
+{
+	if [ -z "${CONFIG_LTO_CLANG}" ]; then
+		return
 	fi
+
+	if [ -z "${CONFIG_MODVERSIONS}" ]; then
+		return
+	fi
+
+	rm -f .tmp_symversions
+
+	for a in built-in.o ${KBUILD_VMLINUX_LIBS}; do
+		for o in $(${AR} t $a); do
+			if [ -f ${o}.symversions ]; then
+				cat ${o}.symversions >> .tmp_symversions
+			fi
+		done
+	done
+
+	echo "-T .tmp_symversions"
 }
 
 # Link of vmlinux.o used for section mismatch analysis
@@ -84,7 +115,16 @@ modpost_link()
 			${KBUILD_VMLINUX_LIBS}				\
 			--end-group"
 	fi
-	${LD} ${LDFLAGS} -r -o ${1} ${objects}
+
+	if [ -n "${CONFIG_LTO_CLANG}" ]; then
+		# This might take a while, so indicate that we're doing
+		# an LTO link
+		info LTO vmlinux.o
+	else
+		info LD vmlinux.o
+	fi
+
+	${LD} ${LDFLAGS} -r -o ${1} $(modversions) ${objects}
 }
 
 # Link of vmlinux
@@ -96,8 +136,16 @@ vmlinux_link()
 	local objects
 
 	if [ "${SRCARCH}" != "um" ]; then
-		if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
-			objects="--whole-archive			\
+		local ld=${LD}
+		local ldflags="${LDFLAGS} ${LDFLAGS_vmlinux}"
+
+		if [ -n "${LDFINAL_vmlinux}" ]; then
+			ld=${LDFINAL_vmlinux}
+			ldflags="${LDFLAGS_FINAL_vmlinux} ${LDFLAGS_vmlinux}"
+		fi
+
+		if [[ -n "${CONFIG_THIN_ARCHIVES}" && -z "${CONFIG_LTO_CLANG}" ]]; then
+			objects="--whole-archive 			\
 				built-in.o				\
 				--no-whole-archive			\
 				--start-group				\
@@ -113,8 +161,7 @@ vmlinux_link()
 				${1}"
 		fi
 
-		${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}		\
-			-T ${lds} ${objects}
+		${ld} ${ldflags} -o ${2} -T ${lds} ${objects}
 	else
 		if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
 			objects="-Wl,--whole-archive			\
@@ -141,7 +188,6 @@ vmlinux_link()
 	fi
 }
 
-
 # Create ${2} .o file with all symbols from the ${1} object file
 kallsyms()
 {
@@ -192,6 +238,7 @@ cleanup()
 	rm -f .tmp_System.map
 	rm -f .tmp_kallsyms*
 	rm -f .tmp_version
+	rm -f .tmp_symversions
 	rm -f .tmp_vmlinux*
 	rm -f built-in.o
 	rm -f System.map
@@ -253,12 +300,19 @@ ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init GCC_PLUGINS_CFLAGS="${GC
 archive_builtin
 
 #link vmlinux.o
-info LD vmlinux.o
 modpost_link vmlinux.o
 
 # modpost vmlinux.o to check for section mismatches
 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
 
+if [ -n "${CONFIG_LTO_CLANG}" ]; then
+	# Re-use vmlinux.o, so we can avoid the slow LTO link step in
+	# vmlinux_link
+	KBUILD_VMLINUX_INIT=
+	KBUILD_VMLINUX_MAIN=vmlinux.o
+	KBUILD_VMLINUX_LIBS=
+fi
+
 kallsymso=""
 kallsyms_vmlinux=""
 if [ -n "${CONFIG_KALLSYMS}" ]; then