VERSION = 4
PATCHLEVEL = 9
-SUBLEVEL = 72
+SUBLEVEL = 95
EXTRAVERSION =
NAME = Roaring Lionus
ifneq ($(filter 4.%,$(MAKE_VERSION)),) # make-4
ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
quiet=silent_
+ tools_silent=s
endif
else # make-3.8x
ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
quiet=silent_
+ tools_silent=-s
endif
endif
# Make variables (CC, etc...)
AS = $(CROSS_COMPILE)as
LD = $(CROSS_COMPILE)ld
+LDGOLD = $(CROSS_COMPILE)ld.gold
CC = $(CROSS_COMPILE)gcc
CPP = $(CC) -E
AR = $(CROSS_COMPILE)ar
CFLAGS_KCOV := $(call cc-option,-fsanitize-coverage=trace-pc,)
export CFLAGS_GCOV CFLAGS_KCOV
+# Make toolchain changes before including arch/$(SRCARCH)/Makefile to ensure
+# ar/cc/ld-* macros return correct values.
+ifdef CONFIG_LTO_CLANG
+# use GNU gold with LLVMgold for LTO linking, and LD for vmlinux_link
+LDFINAL_vmlinux := $(LD)
+LD := $(LDGOLD)
+LDFLAGS += -plugin LLVMgold.so
+# use llvm-ar for building symbol tables from IR files, and llvm-dis instead
+# of objdump for processing symbol versions and exports
+LLVM_AR := llvm-ar
+LLVM_DIS := llvm-dis
+export LLVM_AR LLVM_DIS
+endif
+
# The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
# values of the respective KBUILD_* variables
ARCH_CPPFLAGS :=
KBUILD_CFLAGS += $(call cc-option,-fdata-sections,)
endif
+ifdef CONFIG_LTO_CLANG
+lto-clang-flags := -flto -fvisibility=hidden
+
+# allow disabling only clang LTO where needed
+DISABLE_LTO_CLANG := -fno-lto -fvisibility=default
+export DISABLE_LTO_CLANG
+endif
+
+ifdef CONFIG_LTO
+lto-flags := $(lto-clang-flags)
+KBUILD_CFLAGS += $(lto-flags)
+
+DISABLE_LTO := $(DISABLE_LTO_CLANG)
+export DISABLE_LTO
+
+# LDFINAL_vmlinux and LDFLAGS_FINAL_vmlinux can be set to override
+# the linker and flags for vmlinux_link.
+export LDFINAL_vmlinux LDFLAGS_FINAL_vmlinux
+endif
+
+ifdef CONFIG_CFI_CLANG
+cfi-clang-flags += -fsanitize=cfi
+DISABLE_CFI_CLANG := -fno-sanitize=cfi
+ifdef CONFIG_MODULES
+cfi-clang-flags += -fsanitize-cfi-cross-dso
+DISABLE_CFI_CLANG += -fno-sanitize-cfi-cross-dso
+endif
+ifdef CONFIG_CFI_PERMISSIVE
+cfi-clang-flags += -fsanitize-recover=cfi -fno-sanitize-trap=cfi
+endif
+
+# also disable CFI when LTO is disabled
+DISABLE_LTO_CLANG += $(DISABLE_CFI_CLANG)
+# allow disabling only clang CFI where needed
+export DISABLE_CFI_CLANG
+endif
+
+ifdef CONFIG_CFI
+# cfi-flags are re-tested in prepare-compiler-check
+cfi-flags := $(cfi-clang-flags)
+KBUILD_CFLAGS += $(cfi-flags)
+
+DISABLE_CFI := $(DISABLE_CFI_CLANG)
+DISABLE_LTO += $(DISABLE_CFI)
+export DISABLE_CFI
+endif
+
ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
KBUILD_CFLAGS += $(call cc-option,-Oz,-Os)
KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,)
# disable invalid "can't wrap" optimizations for signed / pointers
KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow)
+# clang sets -fmerge-all-constants by default as optimization, but this
+# is non-conforming behavior for C and in fact breaks the kernel, so we
+# need to disable it here generally.
+KBUILD_CFLAGS += $(call cc-option,-fno-merge-all-constants)
+
+# for gcc -fno-merge-all-constants disables everything, but it is fine
+# to have actual conforming behavior enabled.
+KBUILD_CFLAGS += $(call cc-option,-fmerge-constants)
+
+# Make sure -fstack-check isn't enabled (like gentoo apparently did)
+KBUILD_CFLAGS += $(call cc-option,-fno-stack-check,)
+
# conserve stack if available
KBUILD_CFLAGS += $(call cc-option,-fconserve-stack)
# CC_STACKPROTECTOR_STRONG! Why did it build with _REGULAR?!")
PHONY += prepare-compiler-check
prepare-compiler-check: FORCE
+# Make sure we're using a supported toolchain with LTO_CLANG
+ifdef CONFIG_LTO_CLANG
+ ifneq ($(call clang-ifversion, -ge, 0500, y), y)
+ @echo Cannot use CONFIG_LTO_CLANG: requires clang 5.0 or later >&2 && exit 1
+ endif
+ ifneq ($(call gold-ifversion, -ge, 112000000, y), y)
+ @echo Cannot use CONFIG_LTO_CLANG: requires GNU gold 1.12 or later >&2 && exit 1
+ endif
+endif
+# Make sure compiler supports LTO flags
+ifdef lto-flags
+ ifeq ($(call cc-option, $(lto-flags)),)
+ @echo Cannot use CONFIG_LTO: $(lto-flags) not supported by compiler \
+ >&2 && exit 1
+ endif
+endif
# Make sure compiler supports requested stack protector flag.
ifdef stackp-name
ifeq ($(call cc-option, $(stackp-flag)),)
$(stackp-flag) available but compiler is broken >&2 && exit 1
endif
endif
+ifdef cfi-flags
+ ifeq ($(call cc-option, $(cfi-flags)),)
+ @echo Cannot use CONFIG_CFI: $(cfi-flags) not supported by compiler >&2 && exit 1
+ endif
+endif
@:
# Generate some files
-o -name modules.builtin -o -name '.tmp_*.o.*' \
-o -name '*.c.[012]*.*' \
-o -name '*.ll' \
- -o -name '*.gcno' \) -type f -print | xargs rm -f
+ -o -name '*.gcno' \
+ -o -name '*.*.symversions' \) -type f -print | xargs rm -f
# Generate tags for editors
# ---------------------------------------------------------------------------
# Clear a bunch of variables before executing the submake
tools/: FORCE
$(Q)mkdir -p $(objtree)/tools
- $(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(filter --j% -j,$(MAKEFLAGS))" O=$(shell cd $(objtree) && /bin/pwd) subdir=tools -C $(src)/tools/
+ $(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(shell cd $(objtree) && /bin/pwd) subdir=tools -C $(src)/tools/
tools/%: FORCE
$(Q)mkdir -p $(objtree)/tools
- $(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(filter --j% -j,$(MAKEFLAGS))" O=$(shell cd $(objtree) && /bin/pwd) subdir=tools -C $(src)/tools/ $*
+ $(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(shell cd $(objtree) && /bin/pwd) subdir=tools -C $(src)/tools/ $*
# Single targets
# ---------------------------------------------------------------------------
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