diff -drupN a/scripts/Makefile.build b/scripts/Makefile.build
--- a/scripts/Makefile.build	2018-08-06 17:23:04.000000000 +0300
+++ b/scripts/Makefile.build	2022-06-12 05:28:14.000000000 +0300
@@ -176,6 +176,14 @@ cmd_cc_symtypes_c =
 $(obj)/%.symtypes : $(src)/%.c FORCE
 	$(call cmd,cc_symtypes_c)
 
+# LLVM assembly
+# Generate .ll files from .c
+quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
+      cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
+
+$(obj)/%.ll: $(src)/%.c FORCE
+	$(call if_changed_dep,cc_ll_c)
+
 # C (.c) files
 # The C file is compiled and updated dependency information is generated.
 # (See cmd_cc_o_c + relevant part of rule_cc_o_c)
@@ -200,6 +208,23 @@ 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))	\
@@ -212,12 +237,19 @@ cmd_modversions_c =								\
 		mv -f $(@D)/.tmp_$(@F) $@;					\
 	fi;
 endif
+endif
 
 ifdef CONFIG_FTRACE_MCOUNT_RECORD
 ifdef BUILD_C_RECORDMCOUNT
 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
   RECORDMCOUNT_FLAGS = -w
 endif
+
+ifdef CONFIG_LTO_CLANG
+# With LTO, we postpone running recordmcount until after the LTO link step, so
+# let's export the parameters for the link script.
+export RECORDMCOUNT_FLAGS
+else
 # Due to recursion, we must skip empty.o.
 # The empty.o file is created in the make process in order to determine
 #  the target endianness and word size. It is made before all other C
@@ -226,23 +258,29 @@ sub_cmd_record_mcount =					\
 	if [ $(@) != "scripts/mod/empty.o" ]; then	\
 		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\
 	fi;
+endif
+
 recordmcount_source := $(srctree)/scripts/recordmcount.c \
 		    $(srctree)/scripts/recordmcount.h
-else
+else # !BUILD_C_RECORDMCOUNT
 sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
 	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
 	"$(if $(CONFIG_64BIT),64,32)" \
 	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
 	"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
 	"$(if $(part-of-module),1,0)" "$(@)";
+
 recordmcount_source := $(srctree)/scripts/recordmcount.pl
-endif
+endif # BUILD_C_RECORDMCOUNT
+
+ifndef CONFIG_LTO_CLANG
 cmd_record_mcount =						\
 	if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =	\
 	     "$(CC_FLAGS_FTRACE)" ]; then			\
 		$(sub_cmd_record_mcount)			\
 	fi;
 endif
+endif # CONFIG_FTRACE_MCOUNT_RECORD
 
 ifdef CONFIG_STACK_VALIDATION
 ifneq ($(SKIP_STACK_VALIDATION),1)
@@ -429,9 +467,30 @@ $(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 $@; $(AR) rcST$(KBUILD_ARFLAGS)
-  cmd_make_empty_builtin = rm -f $@; $(AR) rcST$(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
   cmd_make_builtin = $(LD) $(ld_flags) -r -o
@@ -471,7 +530,11 @@ ifdef lib-target
 quiet_cmd_link_l_target = AR      $@
 
 ifdef CONFIG_THIN_ARCHIVES
-  cmd_link_l_target = rm -f $@; $(AR) rcsT$(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
@@ -489,14 +552,36 @@ else
 ref_prefix = EXTERN(
 endif
 
-quiet_cmd_export_list = EXPORTS $@
-cmd_export_list = $(OBJDUMP) -h $< | \
-	sed -ne '/___ksymtab/{s/.*+/$(ref_prefix)/;s/ .*/)/;p}' >$(ksyms-lds);\
-	rm -f $(dummy-object);\
-	$(AR) rcs$(KBUILD_ARFLAGS) $(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)
 
@@ -520,20 +605,36 @@ $($(subst $(obj)/,,$(@:.o=-objs)))    \
 $($(subst $(obj)/,,$(@:.o=-y)))       \
 $($(subst $(obj)/,,$(@:.o=-m)))), $^)
 
-quiet_cmd_link_multi-y = LD      $@
-cmd_link_multi-y = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
+cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secanalysis)
+
+ifdef CONFIG_THIN_ARCHIVES
+  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)
+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-y)
+
+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)