Commit f48cb657 authored by Stephen Rothwell's avatar Stephen Rothwell
Browse files

Merge remote-tracking branch 'kspp/for-next/kspp'

# Conflicts:
#	include/asm-generic/vmlinux.lds.h
parents 6f0666af 112b6a8e
......@@ -42,6 +42,7 @@
*.so.dbg
*.su
*.symtypes
*.symversions
*.tab.[ch]
*.tar
*.xz
......
......@@ -852,12 +852,8 @@ 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 ($(call cc-option-yn, -mnop-mcount),y)
CC_FLAGS_FTRACE += -mnop-mcount
......@@ -865,6 +861,12 @@ ifdef CONFIG_FTRACE_MCOUNT_RECORD
endif
endif
endif
ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
ifdef CONFIG_HAVE_C_RECORDMCOUNT
BUILD_C_RECORDMCOUNT := y
export BUILD_C_RECORDMCOUNT
endif
endif
ifdef CONFIG_HAVE_FENTRY
ifeq ($(call cc-option-yn, -mfentry),y)
CC_FLAGS_FTRACE += -mfentry
......@@ -874,12 +876,6 @@ 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
......@@ -898,6 +894,24 @@ 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
......@@ -1488,7 +1502,7 @@ 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
#
......@@ -1734,7 +1748,7 @@ 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:
......@@ -1831,7 +1845,8 @@ 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
# ---------------------------------------------------------------------------
......
......@@ -631,6 +631,96 @@ 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
......
......@@ -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
......
......@@ -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
......
......@@ -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), $(KBUILD_CFLAGS))
GCOV_PROFILE := n
# Sanitizer runtimes are unavailable and cannot be linked here.
......
......@@ -16,6 +16,7 @@ lkdtm-$(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 += $(CC_FLAGS_LTO)
OBJCOPYFLAGS :=
OBJCOPYFLAGS_rodata_objcopy.o := \
......
......@@ -90,10 +90,13 @@
* .data. We don't want to pull in .data..other sections, which Linux
* has defined. Same for text and bss.
*
* With LTO_CLANG, the linker also splits sections by default, so we need
* these macros to combine the sections during the final link.
*
* RODATA_MAIN is not used because existing code already defines .rodata.x
* sections to be brought in with rodata.
*/
#ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
#if defined(CONFIG_LD_DEAD_CODE_DATA_ELIMINATION) || defined(CONFIG_LTO_CLANG)
#define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_*
#define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
......
......@@ -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;
......
......@@ -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, \
......
......@@ -2281,6 +2281,7 @@ 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.
......
......@@ -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
......
......@@ -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)
......
......@@ -123,9 +123,11 @@ 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), \
......
......@@ -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))
......
......@@ -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)
......
#!/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?";