24 files changed, 704 insertions, 59 deletions
diff --git a/.gitignore b/.gitignore
index bb65fa253e58..3af66272d6f1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -42,6 +42,7 @@
 *.so.dbg
 *.su
 *.symtypes
+*.symversions
 *.tab.[ch]
 *.tar
 *.xz
diff --git a/Makefile b/Makefile
index ac0251444b58..441fe2b223ac 100644
--- a/Makefile
+++ b/Makefile
@@ -853,12 +853,8 @@ KBUILD_CFLAGS += $(DEBUG_CFLAGS)
 export DEBUG_CFLAGS
 
 ifdef CONFIG_FUNCTION_TRACER
-ifdef CONFIG_FTRACE_MCOUNT_RECORD
-  # gcc 5 supports generating the mcount tables directly
-  ifeq ($(call cc-option-yn,-mrecord-mcount),y)
-    CC_FLAGS_FTRACE	+= -mrecord-mcount
-    export CC_USING_RECORD_MCOUNT := 1
-  endif
+ifdef CONFIG_FTRACE_MCOUNT_USE_CC
+  CC_FLAGS_FTRACE	+= -mrecord-mcount
   ifdef CONFIG_HAVE_NOP_MCOUNT
     ifeq ($(call cc-option-yn, -mnop-mcount),y)
       CC_FLAGS_FTRACE	+= -mnop-mcount
@@ -866,6 +862,12 @@ ifdef CONFIG_FTRACE_MCOUNT_RECORD
     endif
   endif
 endif
+ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
+  ifdef CONFIG_HAVE_C_RECORDMCOUNT
+    BUILD_C_RECORDMCOUNT := y
+    export BUILD_C_RECORDMCOUNT
+  endif
+endif
 ifdef CONFIG_HAVE_FENTRY
   ifeq ($(call cc-option-yn, -mfentry),y)
     CC_FLAGS_FTRACE	+= -mfentry
@@ -875,12 +877,6 @@ endif
 export CC_FLAGS_FTRACE
 KBUILD_CFLAGS	+= $(CC_FLAGS_FTRACE) $(CC_FLAGS_USING)
 KBUILD_AFLAGS	+= $(CC_FLAGS_USING)
-ifdef CONFIG_DYNAMIC_FTRACE
-	ifdef CONFIG_HAVE_C_RECORDMCOUNT
-		BUILD_C_RECORDMCOUNT := y
-		export BUILD_C_RECORDMCOUNT
-	endif
-endif
 endif
 
 # We trigger additional mismatches with less inlining
@@ -899,6 +895,24 @@ KBUILD_CFLAGS	+= $(CC_FLAGS_SCS)
 export CC_FLAGS_SCS
 endif
 
+ifdef CONFIG_LTO_CLANG
+ifdef CONFIG_LTO_CLANG_THIN
+CC_FLAGS_LTO	:= -flto=thin -fsplit-lto-unit
+KBUILD_LDFLAGS	+= --thinlto-cache-dir=$(extmod-prefix).thinlto-cache
+else
+CC_FLAGS_LTO	:= -flto
+endif
+CC_FLAGS_LTO	+= -fvisibility=hidden
+
+# Limit inlining across translation units to reduce binary size
+KBUILD_LDFLAGS += -mllvm -import-instr-limit=5
+endif
+
+ifdef CONFIG_LTO
+KBUILD_CFLAGS	+= $(CC_FLAGS_LTO)
+export CC_FLAGS_LTO
+endif
+
 ifdef CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_32B
 KBUILD_CFLAGS += -falign-functions=32
 endif
@@ -1493,7 +1507,7 @@ MRPROPER_FILES += include/config include/generated          \
 		  *.spec
 
 # Directories & files removed with 'make distclean'
-DISTCLEAN_FILES += tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
+DISTCLEAN_FILES += tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS .thinlto-cache
 
 # clean - Delete most, but leave enough to build external modules
 #
@@ -1739,7 +1753,7 @@ PHONY += compile_commands.json
 
 clean-dirs := $(KBUILD_EXTMOD)
 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \
-	$(KBUILD_EXTMOD)/compile_commands.json
+	$(KBUILD_EXTMOD)/compile_commands.json $(KBUILD_EXTMOD)/.thinlto-cache
 
 PHONY += help
 help:
@@ -1836,7 +1850,8 @@ clean: $(clean-dirs)
 		-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 9fc4eb8bfdbc..207261f4879d 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -603,6 +603,96 @@ config SHADOW_CALL_STACK
 	  reading and writing arbitrary memory may be able to locate them
 	  and hijack control flow by modifying the stacks.
 
+config LTO
+	bool
+	help
+	  Selected if the kernel will be built using the compiler's LTO feature.
+
+config LTO_CLANG
+	bool
+	select LTO
+	help
+	  Selected if the kernel will be built using Clang's LTO feature.
+
+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.
+
+config ARCH_SUPPORTS_LTO_CLANG_THIN
+	bool
+	help
+	  An architecture should select this option if it can support Clang's
+	  ThinLTO mode.
+
+config HAS_LTO_CLANG
+	def_bool y
+	# Clang >= 11: https://github.com/ClangBuiltLinux/linux/issues/510
+	depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD
+	depends on $(success,test $(LLVM) -eq 1)
+	depends on $(success,test $(LLVM_IAS) -eq 1)
+	depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
+	depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
+	depends on ARCH_SUPPORTS_LTO_CLANG
+	depends on !FTRACE_MCOUNT_USE_RECORDMCOUNT
+	depends on !KASAN
+	depends on !GCOV_KERNEL
+	help
+	  The compiler and Kconfig options support building with Clang's
+	  LTO.
+
+choice
+	prompt "Link Time Optimization (LTO)"
+	default LTO_NONE
+	help
+	  This option enables Link Time Optimization (LTO), which allows the
+	  compiler to optimize binaries globally.
+
+	  If unsure, select LTO_NONE. Note that LTO is very resource-intensive
+	  so it's disabled by default.
+
+config LTO_NONE
+	bool "None"
+	help
+	  Build the kernel normally, without Link Time Optimization (LTO).
+
+config LTO_CLANG_FULL
+	bool "Clang Full LTO (EXPERIMENTAL)"
+	depends on HAS_LTO_CLANG
+	depends on !COMPILE_TEST
+	select LTO_CLANG
+	help
+          This option enables Clang's full Link Time Optimization (LTO), which
+          allows the compiler to optimize the kernel globally. If you enable
+          this option, the compiler generates LLVM bitcode instead of ELF
+          object files, and the actual compilation from bitcode happens at
+          the LTO link step, which may take several minutes depending on the
+          kernel configuration. More information can be found from LLVM's
+          documentation:
+
+	    https://llvm.org/docs/LinkTimeOptimization.html
+
+	  During link time, this option can use a large amount of RAM, and
+	  may take much longer than the ThinLTO option.
+
+config LTO_CLANG_THIN
+	bool "Clang ThinLTO (EXPERIMENTAL)"
+	depends on HAS_LTO_CLANG && ARCH_SUPPORTS_LTO_CLANG_THIN
+	select LTO_CLANG
+	help
+	  This option enables Clang's ThinLTO, which allows for parallel
+	  optimization and faster incremental compiles compared to the
+	  CONFIG_LTO_CLANG_FULL option. More information can be found
+	  from Clang's documentation:
+
+	    https://clang.llvm.org/docs/ThinLTO.html
+
+	  If unsure, say Y.
+endchoice
+
 config HAVE_ARCH_WITHIN_STACK_FRAMES
 	bool
 	help
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1b8cecdc028e..fd8abf9cb312 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -73,6 +73,8 @@ config ARM64
 	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
 	select ARCH_SUPPORTS_MEMORY_FAILURE
 	select ARCH_SUPPORTS_SHADOW_CALL_STACK if CC_HAVE_SHADOW_CALL_STACK
+	select ARCH_SUPPORTS_LTO_CLANG if CPU_LITTLE_ENDIAN
+	select ARCH_SUPPORTS_LTO_CLANG_THIN
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
 	select ARCH_SUPPORTS_NUMA_BALANCING
@@ -162,6 +164,8 @@ config ARM64
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS \
 		if $(cc-option,-fpatchable-function-entry=2)
+	select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \
+		if DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select HAVE_FAST_GUP
 	select HAVE_FTRACE_MCOUNT_RECORD
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index 76c0255ecc91..945e6bb326e3 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -29,7 +29,8 @@ ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv	\
 ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
 ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
 
-CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS)
+CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS) \
+				$(CC_FLAGS_LTO)
 KASAN_SANITIZE			:= n
 UBSAN_SANITIZE			:= n
 OBJECT_FILES_NON_STANDARD	:= y
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 8a94388e38b3..c23466e05e60 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -38,6 +38,8 @@ KBUILD_CFLAGS			:= $(cflags-y) -Os -DDISABLE_BRANCH_PROFILING \
 
 # remove SCS flags from all objects in this directory
 KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
+# disable LTO
+KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO), $(KBUILD_CFLAGS))
 
 GCOV_PROFILE			:= n
 # Sanitizer runtimes are unavailable and cannot be linked here.
diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
index 6b888d04392d..aa12097668d3 100644
--- a/drivers/misc/lkdtm/Makefile
+++ b/drivers/misc/lkdtm/Makefile
@@ -16,6 +16,7 @@ lkdtm-$(CONFIG_PPC_BOOK3S_64)	+= powerpc.o
 KASAN_SANITIZE_rodata.o		:= n
 KASAN_SANITIZE_stackleak.o	:= n
 KCOV_INSTRUMENT_rodata.o	:= n
+CFLAGS_REMOVE_rodata.o		+= $(CC_FLAGS_LTO)
 
 OBJCOPYFLAGS :=
 OBJCOPYFLAGS_rodata_objcopy.o	:= \
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 01a3fd6a64d2..d4bddfe75e4a 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -90,10 +90,13 @@
  * .data. We don't want to pull in .data..other sections, which Linux
  * has defined. Same for text and bss.
  *
+ * With LTO_CLANG, the linker also splits sections by default, so we need
+ * these macros to combine the sections during the final link.
+ *
  * 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..L* .data..compoundliteral* .data.$__unnamed_* .data.$Lubsan_*
 #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
diff --git a/include/linux/init.h b/include/linux/init.h
index e668832ef66a..a01f01c1a5c5 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -184,19 +184,80 @@ extern bool initcall_debug;
  * as KEEP() in the linker script.
  */
 
+/* Format: <modname>__<counter>_<line>_<fn> */
+#define __initcall_id(fn)					\
+	__PASTE(__KBUILD_MODNAME,				\
+	__PASTE(__,						\
+	__PASTE(__COUNTER__,					\
+	__PASTE(_,						\
+	__PASTE(__LINE__,					\
+	__PASTE(_, fn))))))
+
+/* Format: __<prefix>__<iid><id> */
+#define __initcall_name(prefix, __iid, id)			\
+	__PASTE(__,						\
+	__PASTE(prefix,						\
+	__PASTE(__,						\
+	__PASTE(__iid, id))))
+
+#ifdef CONFIG_LTO_CLANG
+/*
+ * With LTO, the compiler doesn't necessarily obey link order for
+ * initcalls. In order to preserve the correct order, we add each
+ * variable into its own section and generate a linker script (in
+ * scripts/link-vmlinux.sh) to specify the order of the sections.
+ */
+#define __initcall_section(__sec, __iid)			\
+	#__sec ".init.." #__iid
+
+/*
+ * With LTO, the compiler can rename static functions to avoid
+ * global naming collisions. We use a global stub function for
+ * initcalls to create a stable symbol name whose address can be
+ * taken in inline assembly when PREL32 relocations are used.
+ */
+#define __initcall_stub(fn, __iid, id)				\
+	__initcall_name(initstub, __iid, id)
+
+#define __define_initcall_stub(__stub, fn)			\
+	int __init __stub(void);				\
+	int __init __stub(void)					\
+	{ 							\
+		return fn();					\
+	}							\
+	__ADDRESSABLE(__stub)
+#else
+#define __initcall_section(__sec, __iid)			\
+	#__sec ".init"
+
+#define __initcall_stub(fn, __iid, id)	fn
+
+#define __define_initcall_stub(__stub, fn)			\
+	__ADDRESSABLE(fn)
+#endif
+
 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
-#define ___define_initcall(fn, id, __sec)			\
-	__ADDRESSABLE(fn)					\
-	asm(".section	\"" #__sec ".init\", \"a\"	\n"	\
-	"__initcall_" #fn #id ":			\n"	\
-	    ".long	" #fn " - .			\n"	\
+#define ____define_initcall(fn, __stub, __name, __sec)		\
+	__define_initcall_stub(__stub, fn)			\
+	asm(".section	\"" __sec "\", \"a\"		\n"	\
+	    __stringify(__name) ":			\n"	\
+	    ".long	" __stringify(__stub) " - .	\n"	\
 	    ".previous					\n");
 #else
-#define ___define_initcall(fn, id, __sec) \
-	static initcall_t __initcall_##fn##id __used \
-		__attribute__((__section__(#__sec ".init"))) = fn;
+#define ____define_initcall(fn, __unused, __name, __sec)	\
+	static initcall_t __name __used 			\
+		__attribute__((__section__(__sec))) = fn;
 #endif
 
+#define __unique_initcall(fn, id, __sec, __iid)			\
+	____define_initcall(fn,					\
+		__initcall_stub(fn, __iid, id),			\
+		__initcall_name(initcall, __iid, id),		\
+		__initcall_section(__sec, __iid))
+
+#define ___define_initcall(fn, id, __sec)			\
+	__unique_initcall(fn, id, __sec, __initcall_id(fn))
+
 #define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
 
 /*
@@ -236,7 +297,7 @@ extern bool initcall_debug;
 #define __exitcall(fn)						\
 	static exitcall_t __exitcall_##fn __exit_call = fn
 
-#define console_initcall(fn)	___define_initcall(fn,, .con_initcall)
+#define console_initcall(fn)	___define_initcall(fn, con, .con_initcall)
 
 struct obs_kernel_param {
 	const char *str;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 53f4904ee83d..86c799c97b77 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1926,7 +1926,7 @@ enum pci_fixup_pass {
 };
 
 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
-#define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
+#define ___DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
 				    class_shift, hook)			\
 	__ADDRESSABLE(hook)						\
 	asm(".section "	#sec ", \"a\"				\n"	\
@@ -1935,10 +1935,33 @@ enum pci_fixup_pass {
 	    ".long "	#class ", " #class_shift "		\n"	\
 	    ".long "	#hook " - .				\n"	\
 	    ".previous						\n");
+
+/*
+ * Clang's LTO may rename static functions in C, but has no way to
+ * handle such renamings when referenced from inline asm. To work
+ * around this, create global C stubs for these cases.
+ */
+#ifdef CONFIG_LTO_CLANG
+#define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
+				  class_shift, hook, stub)		\
+	void stub(struct pci_dev *dev);					\
+	void stub(struct pci_dev *dev)					\
+	{ 								\
+		hook(dev); 						\
+	}								\
+	___DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
+				  class_shift, stub)
+#else
+#define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
+				  class_shift, hook, stub)		\
+	___DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
+				  class_shift, hook)
+#endif
+
 #define DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
 				  class_shift, hook)			\
 	__DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
-				  class_shift, hook)
+				  class_shift, hook, __UNIQUE_ID(hook))
 #else
 /* Anonymous variables would be nice... */
 #define DECLARE_PCI_FIXUP_SECTION(section, name, vendor, device, class,	\
diff --git a/init/Kconfig b/init/Kconfig
index 47a3d6502fbd..57f859ea79b9 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2307,6 +2307,7 @@ config TRIM_UNUSED_KSYMS
 config UNUSED_KSYMS_WHITELIST
 	string "Whitelist of symbols to keep in ksymtab"
 	depends on TRIM_UNUSED_KSYMS
+	default "scripts/lto-used-symbollist.txt" if LTO_CLANG
 	help
 	  By default, all unused exported symbols will be un-exported from the
 	  build when TRIM_UNUSED_KSYMS is selected.
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 799dbcfe65ad..61cefb157b59 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -602,6 +602,22 @@ config FTRACE_MCOUNT_RECORD
 	depends on DYNAMIC_FTRACE
 	depends on HAVE_FTRACE_MCOUNT_RECORD
 
+config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	bool
+	depends on FTRACE_MCOUNT_RECORD
+
+config FTRACE_MCOUNT_USE_CC
+	def_bool y
+	depends on $(cc-option,-mrecord-mcount)
+	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	depends on FTRACE_MCOUNT_RECORD
+
+config FTRACE_MCOUNT_USE_RECORDMCOUNT
+	def_bool y
+	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	depends on !FTRACE_MCOUNT_USE_CC
+	depends on FTRACE_MCOUNT_RECORD
+
 config TRACING_MAP
 	bool
 	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 4c058f12dd73..d94fc9ab819d 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -111,7 +111,7 @@ endif
 # ---------------------------------------------------------------------------
 
 quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
-      cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) -fverbose-asm -S -o $@ $<
+      cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $<
 
 $(obj)/%.s: $(src)/%.c FORCE
 	$(call if_changed_dep,cc_s_c)
@@ -166,6 +166,15 @@ ifdef CONFIG_MODVERSIONS
 #   the actual value of the checksum generated by genksyms
 # o remove .tmp_<file>.o to <file>.o
 
+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 $(NM) $@ 2>/dev/null | grep -q __ksymtab; then			\
+		$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
+		    > $@.symversions;						\
+	fi;
+else
 cmd_modversions_c =								\
 	if $(OBJDUMP) -h $@ | grep -q __ksymtab; then				\
 		$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))	\
@@ -177,9 +186,9 @@ cmd_modversions_c =								\
 		rm -f $(@D)/.tmp_$(@F:.o=.ver);					\
 	fi
 endif
+endif
 
-ifdef CONFIG_FTRACE_MCOUNT_RECORD
-ifndef CC_USING_RECORD_MCOUNT
+ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
 # compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
 ifdef BUILD_C_RECORDMCOUNT
 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
@@ -206,8 +215,7 @@ recordmcount_source := $(srctree)/scripts/recordmcount.pl
 endif # BUILD_C_RECORDMCOUNT
 cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),	\
 	$(sub_cmd_record_mcount))
-endif # CC_USING_RECORD_MCOUNT
-endif # CONFIG_FTRACE_MCOUNT_RECORD
+endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
 
 ifdef CONFIG_STACK_VALIDATION
 ifneq ($(SKIP_STACK_VALIDATION),1)
@@ -388,6 +396,18 @@ $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 $(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;
 $(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
 
+# combine symversions for later processing
+quiet_cmd_update_lto_symversions = SYMVER  $@
+ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y)
+      cmd_update_lto_symversions =					\
+	rm -f $@.symversions						\
+	$(foreach n, $(filter-out FORCE,$^),				\
+		$(if $(wildcard $(n).symversions),			\
+			; cat $(n).symversions >> $@.symversions))
+else
+      cmd_update_lto_symversions = echo >/dev/null
+endif
+
 #
 # Rule to compile a set of .o files into one .a file (without symbol table)
 #
@@ -395,8 +415,11 @@ $(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
 quiet_cmd_ar_builtin = AR      $@
       cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs)
 
+quiet_cmd_ar_and_symver = AR      $@
+      cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin)
+
 $(obj)/built-in.a: $(real-obj-y) FORCE
-	$(call if_changed,ar_builtin)
+	$(call if_changed,ar_and_symver)
 
 #
 # Rule to create modules.order file
@@ -416,15 +439,26 @@ $(obj)/modules.order: $(obj-m) FORCE
 #
 # Rule to compile a set of .o files into one .a file (with symbol table)
 #
+quiet_cmd_ar_lib = AR      $@
+      cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar)
+
 $(obj)/lib.a: $(lib-y) FORCE
-	$(call if_changed,ar)
+	$(call if_changed,ar_lib)
 
 # NOTE:
 # Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
 # module is turned into a multi object module, $^ will contain header file
 # dependencies recorded in the .*.cmd file.
+ifdef CONFIG_LTO_CLANG
+quiet_cmd_link_multi-m = AR [M]  $@
+cmd_link_multi-m =						\
+	$(cmd_update_lto_symversions);				\
+	rm -f $@; 						\
+	$(AR) cDPrsT $@ $(filter %.o,$^)
+else
 quiet_cmd_link_multi-m = LD [M]  $@
       cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
+endif
 
 $(multi-used-m): FORCE
 	$(call if_changed,link_multi-m)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index b00855b247e0..2301babd3fbc 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -119,9 +119,11 @@ target-stem = $(basename $(patsubst $(obj)/%,%,$@))
 # These flags are needed for modversions and compiling, so we define them here
 # $(modname_flags) defines KBUILD_MODNAME as the name of the module it will
 # end up in (or would, if it gets compiled in)
-name-fix = $(call stringify,$(subst $(comma),_,$(subst -,_,$1)))
+name-fix-token = $(subst $(comma),_,$(subst -,_,$1))
+name-fix = $(call stringify,$(call name-fix-token,$1))
 basename_flags = -DKBUILD_BASENAME=$(call name-fix,$(basetarget))
-modname_flags  = -DKBUILD_MODNAME=$(call name-fix,$(modname))
+modname_flags  = -DKBUILD_MODNAME=$(call name-fix,$(modname)) \
+		 -D__KBUILD_MODNAME=kmod_$(call name-fix-token,$(modname))
 modfile_flags  = -DKBUILD_MODFILE=$(call stringify,$(modfile))
 
 _c_flags       = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index d49ec001825d..6de2c35b64e8 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -30,6 +30,12 @@ quiet_cmd_cc_o_c = CC [M]  $@
 
 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
 
+ifdef CONFIG_LTO_CLANG
+# With CONFIG_LTO_CLANG, reuse the object file we compiled for modpost to
+# avoid a second slow LTO link
+prelink-ext := .lto
+endif
+
 quiet_cmd_ld_ko_o = LD [M]  $@
       cmd_ld_ko_o =                                                     \
 	$(LD) -r $(KBUILD_LDFLAGS)					\
@@ -53,8 +59,9 @@ if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check),      \
 	$(cmd);                                                              \
 	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
 
+
 # Re-generate module BTFs if either module's .ko or vmlinux changed
-$(modules): %.ko: %.o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE
+$(modules): %.ko: %$(prelink-ext).o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE
 	+$(call if_changed_except,ld_ko_o,vmlinux)
 ifdef CONFIG_DEBUG_INFO_BTF_MODULES
 	+$(if $(newer-prereqs),$(call cmd,btf_ko))
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index f54b6ac37ac2..066beffca09a 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -43,6 +43,9 @@ __modpost:
 include include/config/auto.conf
 include scripts/Kbuild.include
 
+# for ld_flags
+include scripts/Makefile.lib
+
 MODPOST = scripts/mod/modpost								\
 	$(if $(CONFIG_MODVERSIONS),-m)							\
 	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)					\
@@ -102,12 +105,30 @@ $(input-symdump):
 	@echo >&2 'WARNING: Symbol version dump "$@" is missing.'
 	@echo >&2 '         Modules may not have dependencies or modversions.'
 
+ifdef CONFIG_LTO_CLANG
+# With CONFIG_LTO_CLANG, .o files might be LLVM bitcode, so we need to run
+# LTO to compile them into native code before running modpost
+prelink-ext := .lto
+
+quiet_cmd_cc_lto_link_modules = LTO [M] $@
+cmd_cc_lto_link_modules =						\
+	$(LD) $(ld_flags) -r -o $@					\
+		$(shell [ -s $(@:.lto.o=.o.symversions) ] &&		\
+			echo -T $(@:.lto.o=.o.symversions))		\
+		--whole-archive $^
+
+%.lto.o: %.o
+	$(call if_changed,cc_lto_link_modules)
+endif
+
+modules := $(sort $(shell cat $(MODORDER)))
+
 # Read out modules.order to pass in modpost.
 # Otherwise, allmodconfig would fail with "Argument list too long".
 quiet_cmd_modpost = MODPOST $@
-      cmd_modpost = sed 's/ko$$/o/' $< | $(MODPOST) -T -
+      cmd_modpost = sed 's/\.ko$$/$(prelink-ext)\.o/' $< | $(MODPOST) -T -
 
-$(output-symdump): $(MODORDER) $(input-symdump) FORCE
+$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(prelink-ext).o) FORCE
 	$(call if_changed,modpost)
 
 targets += $(output-symdump)
diff --git a/scripts/generate_initcall_order.pl b/scripts/generate_initcall_order.pl
new file mode 100755
index 000000000000..1a88d3f1b913
--- /dev/null
+++ b/scripts/generate_initcall_order.pl
@@ -0,0 +1,270 @@
+#!/usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+#
+# Generates a linker script that specifies the correct initcall order.
+#
+# Copyright (C) 2019 Google LLC
+
+use strict;
+use warnings;
+use IO::Handle;
+use IO::Select;
+use POSIX ":sys_wait_h";
+
+my $nm = $ENV{'NM'} || die "$0: ERROR: NM not set?";
+my $objtree = $ENV{'objtree'} || '.';
+
+## currently active child processes
+my $jobs = {};		# child process pid -> file handle
+## results from child processes
+my $results = {};	# object index -> [ { level, secname }, ... ]
+
+## reads _NPROCESSORS_ONLN to determine the maximum number of processes to
+## start
+sub get_online_processors {
+	open(my $fh, "getconf _NPROCESSORS_ONLN 2>/dev/null |")
+		or die "$0: ERROR: failed to execute getconf: $!";
+	my $procs = <$fh>;
+	close($fh);
+
+	if (!($procs =~ /^\d+$/)) {
+		return 1;
+	}
+
+	return int($procs);
+}
+
+## writes results to the parent process
+## format: <file index> <initcall level> <base initcall section name>
+sub write_results {
+	my ($index, $initcalls) = @_;
+
+	# sort by the counter value to ensure the order of initcalls within
+	# each object file is correct
+	foreach my $counter (sort { $a <=> $b } keys(%{$initcalls})) {
+		my $level = $initcalls->{$counter}->{'level'};
+
+		# section name for the initcall function
+		my $secname = $initcalls->{$counter}->{'module'} . '__' .
+			      $counter . '_' .
+			      $initcalls->{$counter}->{'line'} . '_' .
+			      $initcalls->{$counter}->{'function'};
+
+		print "$index $level $secname\n";
+	}
+}
+
+## reads a result line from a child process and adds it to the $results array
+sub read_results{
+	my ($fh) = @_;
+
+	# each child prints out a full line w/ autoflush and exits after the
+	# last line, so even if buffered I/O blocks here, it shouldn't block
+	# very long
+	my $data = <$fh>;
+
+	if (!defined($data)) {
+		return 0;
+	}
+
+	chomp($data);
+
+	my ($index, $level, $secname) = $data =~
+		/^(\d+)\ ([^\ ]+)\ (.*)$/;
+
+	if (!defined($index) ||
+		!defined($level) ||
+		!defined($secname)) {
+		die "$0: ERROR: child process returned invalid data: $data\n";
+	}
+
+	$index = int($index);
+
+	if (!exists($results->{$index})) {
+		$results->{$index} = [];
+	}
+
+	push (@{$results->{$index}}, {
+		'level'   => $level,
+		'secname' => $secname
+	});
+
+	return 1;
+}
+
+## finds initcalls from an object file or all object files in an archive, and
+## writes results back to the parent process
+sub find_initcalls {
+	my ($index, $file) = @_;
+
+	die "$0: ERROR: file $file doesn't exist?" if (! -f $file);
+
+	open(my $fh, "\"$nm\" --defined-only \"$file\" 2>/dev/null |")
+		or die "$0: ERROR: failed to execute \"$nm\": $!";
+
+	my $initcalls = {};
+
+	while (<$fh>) {
+		chomp;
+
+		# check for the start of a new object file (if processing an
+		# archive)
+		my ($path)= $_ =~ /^(.+)\:$/;
+
+		if (defined($path)) {
+			write_results($index, $initcalls);
+			$initcalls = {};
+			next;
+		}
+
+		# look for an initcall
+		my ($module, $counter, $line, $symbol) = $_ =~
+			/[a-z]\s+__initcall__(\S*)__(\d+)_(\d+)_(.*)$/;
+
+		if (!defined($module)) {
+			$module = ''
+		}
+
+		if (!defined($counter) ||
+			!defined($line) ||
+			!defined($symbol)) {
+			next;
+		}
+
+		# parse initcall level
+		my ($function, $level) = $symbol =~
+			/^(.*)((early|rootfs|con|[0-9])s?)$/;
+
+		die "$0: ERROR: invalid initcall name $symbol in $file($path)"
+			if (!defined($function) || !defined($level));
+
+		$initcalls->{$counter} = {
+			'module'   => $module,
+			'line'     => $line,
+			'function' => $function,
+			'level'    => $level,
+		};
+	}
+
+	close($fh);
+	write_results($index, $initcalls);
+}
+
+## waits for any child process to complete, reads the results, and adds them to
+## the $results array for later processing
+sub wait_for_results {
+	my ($select) = @_;
+
+	my $pid = 0;
+	do {
+		# unblock children that may have a full write buffer
+		foreach my $fh ($select->can_read(0)) {
+			read_results($fh);
+		}
+
+		# check for children that have exited, read the remaining data
+		# from them, and clean up
+		$pid = waitpid(-1, WNOHANG);
+		if ($pid > 0) {
+			if (!exists($jobs->{$pid})) {
+				next;
+			}
+
+			my $fh = $jobs->{$pid};
+			$select->remove($fh);
+
+			while (read_results($fh)) {
+				# until eof
+			}
+
+			close($fh);
+			delete($jobs->{$pid});
+		}
+	} while ($pid > 0);
+}
+
+## forks a child to process each file passed in the command line and collects
+## the results
+sub process_files {
+	my $index = 0;
+	my $njobs = $ENV{'PARALLELISM'} || get_online_processors();
+	my $select = IO::Select->new();
+
+	while (my $file = shift(@ARGV)) {
+		# fork a child process and read it's stdout
+		my $pid = open(my $fh, '-|');
+
+		if (!defined($pid)) {
+			die "$0: ERROR: failed to fork: $!";
+		} elsif ($pid) {
+			# save the child process pid and the file handle
+			$select->add($fh);
+			$jobs->{$pid} = $fh;
+		} else {
+			# in the child process
+			STDOUT->autoflush(1);
+			find_initcalls($index, "$objtree/$file");
+			exit;
+		}
+
+		$index++;
+
+		# limit the number of children to $njobs
+		if (scalar(keys(%{$jobs})) >= $njobs) {
+			wait_for_results($select);
+		}
+	}
+
+	# wait for the remaining children to complete
+	while (scalar(keys(%{$jobs})) > 0) {
+		wait_for_results($select);
+	}
+}
+
+sub generate_initcall_lds() {
+	process_files();
+
+	my $sections = {};	# level -> [ secname, ...]
+
+	# sort results to retain link order and split to sections per
+	# initcall level
+	foreach my $index (sort { $a <=> $b } keys(%{$results})) {
+		foreach my $result (@{$results->{$index}}) {
+			my $level = $result->{'level'};
+
+			if (!exists($sections->{$level})) {
+				$sections->{$level} = [];
+			}
+
+			push(@{$sections->{$level}}, $result->{'secname'});
+		}
+	}
+
+	die "$0: ERROR: no initcalls?" if (!keys(%{$sections}));
+
+	# print out a linker script that defines the order of initcalls for
+	# each level
+	print "SECTIONS {\n";
+
+	foreach my $level (sort(keys(%{$sections}))) {
+		my $section;
+
+		if ($level eq 'con') {
+			$section = '.con_initcall.init';
+		} else {
+			$section = ".initcall${level}.init";
+		}
+
+		print "\t${section} : {\n";
+
+		foreach my $secname (@{$sections->{$level}}) {
+			print "\t\t*(${section}..${secname}) ;\n";
+		}
+
+		print "\t}\n";
+	}
+
+	print "}\n";
+}
+
+generate_initcall_lds();
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 6eded325c837..c5919d5a0b4f 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -43,11 +43,37 @@ info()
 	fi
 }
 
+# Generate a linker script to ensure correct ordering of initcalls.
+gen_initcalls()
+{
+	info GEN .tmp_initcalls.lds
+
+	${PYTHON} ${srctree}/scripts/jobserver-exec		\
+	${PERL} ${srctree}/scripts/generate_initcall_order.pl	\
+		${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}	\
+		> .tmp_initcalls.lds
+}
+
+# If CONFIG_LTO_CLANG is selected, collect generated symbol versions into
+# .tmp_symversions.lds
+gen_symversions()
+{
+	info GEN .tmp_symversions.lds
+	rm -f .tmp_symversions.lds
+
+	for o in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do
+		if [ -f ${o}.symversions ]; then
+			cat ${o}.symversions >> .tmp_symversions.lds
+		fi
+	done
+}
+
 # Link of vmlinux.o used for section mismatch analysis
 # ${1} output file
 modpost_link()
 {
 	local objects
+	local lds=""
 
 	objects="--whole-archive				\
 		${KBUILD_VMLINUX_OBJS}				\
@@ -56,7 +82,23 @@ modpost_link()
 		${KBUILD_VMLINUX_LIBS}				\
 		--end-group"
 
-	${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects}
+	if [ -n "${CONFIG_LTO_CLANG}" ]; then
+		gen_initcalls
+		lds="-T .tmp_initcalls.lds"
+
+		if [ -n "${CONFIG_MODVERSIONS}" ]; then
+			gen_symversions
+			lds="${lds} -T .tmp_symversions.lds"
+		fi
+
+		# This might take a while, so indicate that we're doing
+		# an LTO link
+		info LTO ${1}
+	else
+		info LD ${1}
+	fi
+
+	${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${lds} ${objects}
 }
 
 objtool_link()
@@ -103,13 +145,22 @@ vmlinux_link()
 	fi
 
 	if [ "${SRCARCH}" != "um" ]; then
-		objects="--whole-archive			\
-			${KBUILD_VMLINUX_OBJS}			\
-			--no-whole-archive			\
-			--start-group				\
-			${KBUILD_VMLINUX_LIBS}			\
-			--end-group				\
-			${@}"
+		if [ -n "${CONFIG_LTO_CLANG}" ]; then
+			# Use vmlinux.o instead of performing the slow LTO
+			# link again.
+			objects="--whole-archive		\
+				vmlinux.o 			\
+				--no-whole-archive		\
+				${@}"
+		else
+			objects="--whole-archive		\
+				${KBUILD_VMLINUX_OBJS}		\
+				--no-whole-archive		\
+				--start-group			\
+				${KBUILD_VMLINUX_LIBS}		\
+				--end-group			\
+				${@}"
+		fi
 
 		${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}	\
 			${strip_debug#-Wl,}			\
@@ -225,6 +276,8 @@ cleanup()
 {
 	rm -f .btf.*
 	rm -f .tmp_System.map
+	rm -f .tmp_initcalls.lds
+	rm -f .tmp_symversions.lds
 	rm -f .tmp_vmlinux*
 	rm -f System.map
 	rm -f vmlinux
@@ -274,7 +327,6 @@ fi;
 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1
 
 #link vmlinux.o
-info LD vmlinux.o
 modpost_link vmlinux.o
 objtool_link vmlinux.o
 
diff --git a/scripts/lto-used-symbollist.txt b/scripts/lto-used-symbollist.txt
new file mode 100644
index 000000000000..38e7bb9ebaae
--- /dev/null
+++ b/scripts/lto-used-symbollist.txt
@@ -0,0 +1,5 @@
+memcpy
+memmove
+memset
+__stack_chk_fail
+__stack_chk_guard
diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
index 78071681d924..c9e38ad937fd 100644
--- a/scripts/mod/Makefile
+++ b/scripts/mod/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 OBJECT_FILES_NON_STANDARD := y
+CFLAGS_REMOVE_empty.o += $(CC_FLAGS_LTO)
 
 hostprogs-always-y	+= modpost mk_elfconfig
 always-y		+= empty.o
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d6c81657d695..be0642126f53 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -17,7 +17,6 @@
 #include <ctype.h>
 #include <string.h>
 #include <limits.h>
-#include <stdbool.h>
 #include <errno.h>
 #include "modpost.h"
 #include "../../include/linux/license.h"
@@ -84,14 +83,6 @@ modpost_log(enum loglevel loglevel, const char *fmt, ...)
 		error_occurred = true;
 }
 
-static inline bool strends(const char *str, const char *postfix)
-{
-	if (strlen(str) < strlen(postfix))
-		return false;
-
-	return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
-}
-
 void *do_nofail(void *ptr, const char *expr)
 {
 	if (!ptr)
@@ -1988,6 +1979,10 @@ 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;
 }
@@ -2011,6 +2006,9 @@ static void read_symbols(const char *modname)
 		/* strip trailing .o */
 		tmp = NOFAIL(strdup(modname));
 		tmp[strlen(tmp) - 2] = '\0';
+		/* strip trailing .lto */
+		if (strends(tmp, ".lto"))
+			tmp[strlen(tmp) - 4] = '\0';
 		mod = new_module(tmp);
 		free(tmp);
 	}
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index e6f46eee0af0..1f76eea7cfde 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -180,6 +181,14 @@ static inline unsigned int get_secindex(const struct elf_info *info,
 	return info->symtab_shndx_start[sym - info->symtab_start];
 }
 
+static inline bool strends(const char *str, const char *postfix)
+{
+	if (strlen(str) < strlen(postfix))
+		return false;
+
+	return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
+}
+
 /* file2alias.c */
 extern unsigned int cross_build;
 void handle_moddevtable(struct module *mod, struct elf_info *info,
diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c
index d587f40f1117..760e6baa7eda 100644
--- a/scripts/mod/sumversion.c
+++ b/scripts/mod/sumversion.c
@@ -391,10 +391,14 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen)
 	struct md4_ctx md;
 	char *fname;
 	char filelist[PATH_MAX + 1];
+	int postfix_len = 1;
+
+	if (strends(modname, ".lto.o"))
+		postfix_len = 5;
 
 	/* objects for a module are listed in the first line of *.mod file. */
 	snprintf(filelist, sizeof(filelist), "%.*smod",
-		 (int)strlen(modname) - 1, modname);
+		 (int)strlen(modname) - postfix_len, modname);
 
 	buf = read_text_file(filelist);
 
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 69b9b71a6a47..18d5b8423635 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -23,6 +23,30 @@ SECTIONS {
 	.init_array		0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }
 
 	__jump_table		0 : ALIGN(8) { KEEP(*(__jump_table)) }
+
+	__patchable_function_entries : { *(__patchable_function_entries) }
+
+	/*
+	 * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and
+	 * -ffunction-sections, which increases the size of the final module.
+	 * Merge the split sections in the final binary.
+	 */
+	.bss : {
+		*(.bss .bss.[0-9a-zA-Z_]*)
+		*(.bss..L*)
+	}
+
+	.data : {
+		*(.data .data.[0-9a-zA-Z_]*)
+		*(.data..L*)
+	}
+
+	.rodata : {
+		*(.rodata .rodata.[0-9a-zA-Z_]*)
+		*(.rodata..L*)
+	}
+
+	.text : { *(.text .text.[0-9a-zA-Z_]*) }
 }
 
 /* bring in arch-specific sections */