diff --git a/Makefile b/Makefile
index 840bde10c9b4..f70ef17a3d2f 100644
--- a/Makefile
+++ b/Makefile
@@ -608,6 +608,16 @@ ifdef CONFIG_FUNCTION_TRACER
   CC_FLAGS_FTRACE := -pg
 endif
 
+# Make toolchain changes before including arch/$(SRCARCH)/Makefile to ensure
+# ar/cc/ld-* macros return correct values.
+ifdef CONFIG_LTO_CLANG
+# use llvm-ar for building symbol tables from IR files, and llvm-nm instead
+# of objdump for processing symbol versions and exports
+LLVM_AR		:= llvm-ar
+LLVM_NM		:= llvm-nm
+export LLVM_AR LLVM_NM
+endif
+
 # The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
 # values of the respective KBUILD_* variables
 ARCH_CPPFLAGS :=
@@ -795,6 +805,22 @@ KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections
 LDFLAGS_vmlinux += --gc-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_CFLAGS	:= $(lto-clang-flags)
+KBUILD_CFLAGS	+= $(LTO_CFLAGS)
+
+DISABLE_LTO	:= $(DISABLE_LTO_CLANG)
+export LTO_CFLAGS DISABLE_LTO
+endif
+
 # arch Makefile may override CC so keep this after arch Makefile is included
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 
@@ -1583,7 +1609,8 @@ 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 6801123932a5..4572791825b6 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -474,6 +474,44 @@ config STACKPROTECTOR_STRONG
 	  about 20% of all kernel functions, which increases the kernel code
 	  size by about 2%.
 
+config LTO
+	def_bool n
+
+config ARCH_SUPPORTS_LTO_CLANG
+	bool
+	help
+	  An architecture should select this option if it supports:
+	  - compiling with clang,
+	  - compiling inline assembly with clang's integrated assembler,
+	  - and linking with LLD.
+
+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
+	depends on CC_IS_CLANG && LD_IS_LLD
+	select LTO
+	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 and
+	  LLD.
+
+endchoice
+
 config HAVE_ARCH_WITHIN_STACK_FRAMES
 	bool
 	help
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index dd38c97933f1..65cbde21a9f4 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -66,7 +66,7 @@
  * RODATA_MAIN is not used because existing code already defines .rodata.x
  * sections to be brought in with rodata.
  */
-#ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
+#if defined(CONFIG_LD_DEAD_CODE_DATA_ELIMINATION) || defined(CONFIG_LTO_CLANG)
 #define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
 #define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..LPBX*
 #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 64fac0ad32d6..30b9860ece7b 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -185,6 +185,23 @@ 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_NM) $(@D)/.tmp_$(@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))	\
@@ -197,6 +214,7 @@ cmd_modversions_c =								\
 		mv -f $(@D)/.tmp_$(@F) $@;					\
 	fi;
 endif
+endif
 
 ifdef CONFIG_FTRACE_MCOUNT_RECORD
 ifndef CC_USING_RECORD_MCOUNT
@@ -429,6 +447,26 @@ $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 # To build objects in subdirs, we need to descend into the directories
 $(sort $(subdir-obj-y)): $(subdir-ym) ;
 
+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
+
 #
 # Rule to compile a set of .o files into one .o file
 #
@@ -439,7 +477,8 @@ ifdef builtin-target
 # scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol
 # table and index.
 quiet_cmd_ar_builtin = AR      $@
-      cmd_ar_builtin = rm -f $@; \
+      cmd_ar_builtin = $(update_lto_symversions) \
+		     rm -f $@; \
                      $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^)
 
 $(builtin-target): $(real-obj-y) FORCE
@@ -468,7 +507,11 @@ ifdef lib-target
 quiet_cmd_link_l_target = AR      $@
 
 # lib target archives do get a symbol table and index
-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)
 
 $(lib-target): $(lib-y) FORCE
 	$(call if_changed,link_l_target)
@@ -479,13 +522,34 @@ dummy-object = $(obj)/.lib_exports.o
 ksyms-lds = $(dot-target).lds
 
 quiet_cmd_export_list = EXPORTS $@
-cmd_export_list = $(OBJDUMP) -h $< | \
-	sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
-	rm -f $(dummy-object);\
+filter_export_list = sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\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)
 
+ifdef CONFIG_LTO_CLANG
+# objdump doesn't understand IR files and llvm-nm 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 $$o | 		\
+				$(filter_export_list) 	\
+				>>$(ksyms-lds);		\
+		else					\
+			$(LLVM_NM) $$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)
 
@@ -509,13 +573,31 @@ $($(subst $(obj)/,,$(@:.o=-objs)))    \
 $($(subst $(obj)/,,$(@:.o=-y)))       \
 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
 
+cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
+
+quiet_cmd_link_multi-y = AR      $@
+cmd_link_multi-y = $(update_lto_symversions) \
+	rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps) \
+	$(update_lto_symtable)
+
 quiet_cmd_link_multi-m = LD [M]  $@
-cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
+
+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)
 
 $(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-m)
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 7d4af0d0accb..dc2d4be47ac8 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 $@
@@ -100,7 +116,6 @@ vmlinux.o: FORCE
 # Declare generated files as targets for modpost
 $(modules:.ko=.mod.c): __modpost ;
 
-
 # Step 5), compile all *.mod.c files
 
 # modname is set to make c_flags define KBUILD_MODNAME
@@ -119,13 +134,24 @@ 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 $(KBUILD_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 c8cf45362bd6..a64e3fd412ab 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -60,6 +60,38 @@ archive_builtin()
 	${AR} rcsTP${KBUILD_ARFLAGS} built-in.a			\
 				${KBUILD_VMLINUX_INIT}		\
 				${KBUILD_VMLINUX_MAIN}
+
+	# rebuild with llvm-ar to update the symbol table
+	if [ -n "${CONFIG_LTO_CLANG}" ]; then
+		mv -f built-in.a built-in.a.tmp
+		${LLVM_AR} rcsT${KBUILD_ARFLAGS} built-in.a $(${AR} t built-in.a.tmp)
+		rm -f built-in.a.tmp
+	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.a ${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
@@ -75,7 +107,13 @@ modpost_link()
 		${KBUILD_VMLINUX_LIBS}				\
 		--end-group"
 
-	${LD} ${KBUILD_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
+	fi
+
+	${LD} ${KBUILD_LDFLAGS} -r -o ${1} $(modversions) ${objects}
 }
 
 # Link of vmlinux
@@ -87,13 +125,20 @@ vmlinux_link()
 	local objects
 
 	if [ "${SRCARCH}" != "um" ]; then
-		objects="--whole-archive			\
-			built-in.a				\
-			--no-whole-archive			\
-			--start-group				\
-			${KBUILD_VMLINUX_LIBS}			\
-			--end-group				\
-			${1}"
+		if [ -z "${CONFIG_LTO_CLANG}" ]; then
+			objects="--whole-archive		\
+				built-in.a			\
+				--no-whole-archive		\
+				--start-group			\
+				${KBUILD_VMLINUX_LIBS}		\
+				--end-group			\
+				${1}"
+		else
+			objects="--start-group			\
+				vmlinux.o			\
+				--end-group			\
+				${1}"
+		fi
 
 		${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}	\
 			-T ${lds} ${objects}
@@ -114,7 +159,6 @@ vmlinux_link()
 	fi
 }
 
-
 # Create ${2} .o file with all symbols from the ${1} object file
 kallsyms()
 {
@@ -159,6 +203,7 @@ cleanup()
 {
 	rm -f .tmp_System.map
 	rm -f .tmp_kallsyms*
+	rm -f .tmp_symversions
 	rm -f .tmp_vmlinux*
 	rm -f built-in.a
 	rm -f System.map
@@ -220,7 +265,6 @@ ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
 archive_builtin
 
 #link vmlinux.o
-info LD vmlinux.o
 modpost_link vmlinux.o
 
 # modpost vmlinux.o to check for section mismatches
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 858cbe56b100..ca5bb33d7460 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -145,6 +145,9 @@ static struct module *new_module(const char *modname)
 		p[strlen(p) - 2] = '\0';
 		mod->is_dot_o = 1;
 	}
+	/* strip trailing .lto */
+	if (strends(p, ".lto"))
+		p[strlen(p) - 4] = '\0';
 
 	/* add to list */
 	mod->name = p;
@@ -1927,6 +1930,10 @@ static char *remove_dot(char *s)
 		size_t m = strspn(s + n + 1, "0123456789");
 		if (m && (s[n + m] == '.' || s[n + m] == 0))
 			s[n] = 0;
+
+		/* strip trailing .lto */
+		if (strends(s, ".lto"))
+			s[strlen(s) - 4] = '\0';
 	}
 	return s;
 }