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-rw-r--r--.gitignore1
-rw-r--r--Makefile45
-rw-r--r--arch/Kconfig90
-rw-r--r--arch/arm64/Kconfig4
-rw-r--r--arch/arm64/kernel/vdso/Makefile3
-rw-r--r--drivers/firmware/efi/libstub/Makefile2
-rw-r--r--drivers/misc/lkdtm/Makefile1
-rw-r--r--include/asm-generic/vmlinux.lds.h5
-rw-r--r--include/linux/init.h79
-rw-r--r--include/linux/pci.h27
-rw-r--r--init/Kconfig1
-rw-r--r--kernel/trace/Kconfig16
-rw-r--r--scripts/Makefile.build48
-rw-r--r--scripts/Makefile.lib6
-rw-r--r--scripts/Makefile.modfinal9
-rw-r--r--scripts/Makefile.modpost25
-rwxr-xr-xscripts/generate_initcall_order.pl270
-rwxr-xr-xscripts/link-vmlinux.sh70
-rw-r--r--scripts/lto-used-symbollist.txt5
-rw-r--r--scripts/mod/Makefile1
-rw-r--r--scripts/mod/modpost.c16
-rw-r--r--scripts/mod/modpost.h9
-rw-r--r--scripts/mod/sumversion.c6
-rw-r--r--scripts/module.lds.S24
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 */