Merge tag 'kbuild-v6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild (61401a87) · Commits · EulixOS / Software / Kernel

.gitignore

+1 −1

Original line number	Diff line number	Diff line
		@@ -74,7 +74,7 @@ modules.order
		#
		# RPM spec file (make rpm-pkg)
		#
		/*.spec
		/kernel.spec
		/rpmbuild/

		#

Documentation/kbuild/kconfig.rst

+17 −0

Original line number	Diff line number	Diff line
		@@ -56,6 +56,15 @@ KCONFIG_OVERWRITECONFIG
		If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
		break symlinks when .config is a symlink to somewhere else.

		KCONFIG_WARN_UNKNOWN_SYMBOLS
		----------------------------
		This environment variable makes Kconfig warn about all unrecognized
		symbols in the config input.

		KCONFIG_WERROR
		--------------
		If set, Kconfig treats warnings as errors.

		`CONFIG_`
		---------
		If you set `CONFIG_` in the environment, Kconfig will prefix all symbols
		@@ -212,6 +221,10 @@ Searching in menuconfig:
		first (and in alphabetical order), then come all other symbols,
		sorted in alphabetical order.

		In this menu, pressing the key in the (#) prefix will jump
		directly to that location. You will be returned to the current
		search results after exiting this new menu.

		----------------------------------------------------------------------

		User interface options for 'menuconfig'
		@@ -264,6 +277,10 @@ Searching in nconfig:
		F8 (SymSearch) searches the configuration symbols for the
		given string or regular expression (regex).

		In the SymSearch, pressing the key in the (#) prefix will
		jump directly to that location. You will be returned to the
		current search results after exiting this new menu.

		NCONFIG_MODE
		------------
		This mode shows all sub-menus in one large tree.

Documentation/kbuild/llvm.rst

+80 −44

Original line number	Diff line number	Diff line
		@@ -25,50 +25,38 @@ objects <https://www.aosabook.org/en/llvm.html>`_. Clang is a front-end to LLVM
		that supports C and the GNU C extensions required by the kernel, and is
		pronounced "klang," not "see-lang."

		Clang
		-----

		The compiler used can be swapped out via ``CC=`` command line argument to ``make``.
		``CC=`` should be set when selecting a config and during a build. ::

		make CC=clang defconfig

		make CC=clang
		Building with LLVM
		------------------

		Cross Compiling
		---------------
		Invoke ``make`` via::

		A single Clang compiler binary will typically contain all supported backends,
		which can help simplify cross compiling. ::

		make ARCH=arm64 CC=clang CROSS_COMPILE=aarch64-linux-gnu-
		make LLVM=1

		``CROSS_COMPILE`` is not used to prefix the Clang compiler binary, instead
		``CROSS_COMPILE`` is used to set a command line flag: ``--target=<triple>``. For
		example: ::
		to compile for the host target. For cross compiling::

		clang --target=aarch64-linux-gnu foo.c
		make LLVM=1 ARCH=arm64

		LLVM Utilities
		--------------
		The LLVM= argument
		------------------

		LLVM has substitutes for GNU binutils utilities. They can be enabled individually.
		The full list of supported make variables::
		LLVM has substitutes for GNU binutils utilities. They can be enabled
		individually. The full list of supported make variables::

		make CC=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \
		OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump READELF=llvm-readelf \
		HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar HOSTLD=ld.lld

		To simplify the above command, Kbuild supports the ``LLVM`` variable::

		make LLVM=1
		``LLVM=1`` expands to the above.

		If your LLVM tools are not available in your PATH, you can supply their
		location using the LLVM variable with a trailing slash::

		make LLVM=/path/to/llvm/

		which will use ``/path/to/llvm/clang``, ``/path/to/llvm/ld.lld``, etc.
		which will use ``/path/to/llvm/clang``, ``/path/to/llvm/ld.lld``, etc. The
		following may also be used::

		PATH=/path/to/llvm:$PATH make LLVM=1

		If your LLVM tools have a version suffix and you want to test with that
		explicit version rather than the unsuffixed executables like ``LLVM=1``, you
		@@ -78,31 +66,72 @@ can pass the suffix using the ``LLVM`` variable::

		which will use ``clang-14``, ``ld.lld-14``, etc.

		To support combinations of out of tree paths with version suffixes, we
		recommend::

		PATH=/path/to/llvm/:$PATH make LLVM=-14

		``LLVM=0`` is not the same as omitting ``LLVM`` altogether, it will behave like
		``LLVM=1``. If you only wish to use certain LLVM utilities, use their respective
		make variables.
		``LLVM=1``. If you only wish to use certain LLVM utilities, use their
		respective make variables.

		The same value used for ``LLVM=`` should be set for each invocation of ``make``
		if configuring and building via distinct commands. ``LLVM=`` should also be set
		as an environment variable when running scripts that will eventually run
		``make``.

		The integrated assembler is enabled by default. You can pass ``LLVM_IAS=0`` to
		disable it.
		Cross Compiling
		---------------

		Omitting CROSS_COMPILE
		A single Clang compiler binary (and corresponding LLVM utilities) will
		typically contain all supported back ends, which can help simplify cross
		compiling especially when ``LLVM=1`` is used. If you use only LLVM tools,
		``CROSS_COMPILE`` or target-triple-prefixes become unnecessary. Example::

		make LLVM=1 ARCH=arm64

		As an example of mixing LLVM and GNU utilities, for a target like ``ARCH=s390``
		which does not yet have ``ld.lld`` or ``llvm-objcopy`` support, you could
		invoke ``make`` via::

		make LLVM=1 ARCH=s390 LD=s390x-linux-gnu-ld.bfd \
		OBJCOPY=s390x-linux-gnu-objcopy

		This example will invoke ``s390x-linux-gnu-ld.bfd`` as the linker and
		``s390x-linux-gnu-objcopy``, so ensure those are reachable in your ``$PATH``.

		``CROSS_COMPILE`` is not used to prefix the Clang compiler binary (or
		corresponding LLVM utilities) as is the case for GNU utilities when ``LLVM=1``
		is not set.

		The LLVM_IAS= argument
		----------------------

		As explained above, ``CROSS_COMPILE`` is used to set ``--target=<triple>``.
		Clang can assemble assembler code. You can pass ``LLVM_IAS=0`` to disable this
		behavior and have Clang invoke the corresponding non-integrated assembler
		instead. Example::

		make LLVM=1 LLVM_IAS=0

		``CROSS_COMPILE`` is necessary when cross compiling and ``LLVM_IAS=0``
		is used in order to set ``--prefix=`` for the compiler to find the
		corresponding non-integrated assembler (typically, you don't want to use the
		system assembler when targeting another architecture). Example::

		If ``CROSS_COMPILE`` is not specified, the ``--target=<triple>`` is inferred
		from ``ARCH``.
		make LLVM=1 ARCH=arm LLVM_IAS=0 CROSS_COMPILE=arm-linux-gnueabi-

		That means if you use only LLVM tools, ``CROSS_COMPILE`` becomes unnecessary.

		For example, to cross-compile the arm64 kernel::
		Ccache
		------

		make ARCH=arm64 LLVM=1
		``ccache`` can be used with ``clang`` to improve subsequent builds, (though
		KBUILD_BUILD_TIMESTAMP_ should be set to a deterministic value between builds
		in order to avoid 100% cache misses, see Reproducible_builds_ for more info):

		If ``LLVM_IAS=0`` is specified, ``CROSS_COMPILE`` is also used to derive
		``--prefix=<path>`` to search for the GNU assembler and linker. ::
		KBUILD_BUILD_TIMESTAMP='' make LLVM=1 CC="ccache clang"

		make ARCH=arm64 LLVM=1 LLVM_IAS=0 CROSS_COMPILE=aarch64-linux-gnu-
		.. _KBUILD_BUILD_TIMESTAMP: kbuild.html#kbuild-build-timestamp
		.. _Reproducible_builds: reproducible-builds.html#timestamps

		Supported Architectures
		-----------------------
		@@ -135,14 +164,17 @@ yet. Bug reports are always welcome at the issue tracker below!
		* - hexagon
		- Maintained
		- ``LLVM=1``
		* - loongarch
		- Maintained
		- ``LLVM=1``
		* - mips
		- Maintained
		- ``LLVM=1``
		* - powerpc
		- Maintained
		- ``CC=clang``
		- ``LLVM=1``
		* - riscv
		- Maintained
		- Supported
		- ``LLVM=1``
		* - s390
		- Maintained
		@@ -171,7 +203,11 @@ Getting Help
		Getting LLVM
		-------------

		We provide prebuilt stable versions of LLVM on `kernel.org <https://kernel.org/pub/tools/llvm/>`_.
		We provide prebuilt stable versions of LLVM on `kernel.org
		<https://kernel.org/pub/tools/llvm/>`_. These have been optimized with profile
		data for building Linux kernels, which should improve kernel build times
		relative to other distributions of LLVM.

		Below are links that may be useful for building LLVM from source or procuring
		it through a distribution's package manager.

MAINTAINERS

+1 −0

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		@@ -11382,6 +11382,7 @@ F: scripts/dummy-tools/
		F: scripts/mk*
		F: scripts/mod/
		F: scripts/package/
		F: usr/

		KERNEL HARDENING (not covered by other areas)
		M: Kees Cook <keescook@chromium.org>

Makefile

+30 −142

Original line number	Diff line number	Diff line
		@@ -280,8 +280,8 @@ no-dot-config-targets := $(clean-targets) \
		# Installation targets should not require compiler. Unfortunately, vdso_install
		# is an exception where build artifacts may be updated. This must be fixed.
		no-compiler-targets := $(no-dot-config-targets) install dtbs_install \
		headers_install modules_install kernelrelease image_name
		no-sync-config-targets := $(no-dot-config-targets) %install kernelrelease \
		headers_install modules_install modules_sign kernelrelease image_name
		no-sync-config-targets := $(no-dot-config-targets) %install modules_sign kernelrelease \
		image_name
		single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.rsi %.s %.symtypes %/

		@@ -510,7 +510,6 @@ LEX = flex
		YACC = bison
		AWK = awk
		INSTALLKERNEL := installkernel
		DEPMOD = depmod
		PERL = perl
		PYTHON3 = python3
		CHECK = sparse
		@@ -564,14 +563,6 @@ KBUILD_CFLAGS += -funsigned-char
		KBUILD_CFLAGS += -fno-common
		KBUILD_CFLAGS += -fno-PIE
		KBUILD_CFLAGS += -fno-strict-aliasing
		KBUILD_CFLAGS += -Wall
		KBUILD_CFLAGS += -Wundef
		KBUILD_CFLAGS += -Werror=implicit-function-declaration
		KBUILD_CFLAGS += -Werror=implicit-int
		KBUILD_CFLAGS += -Werror=return-type
		KBUILD_CFLAGS += -Werror=strict-prototypes
		KBUILD_CFLAGS += -Wno-format-security
		KBUILD_CFLAGS += -Wno-trigraphs

		KBUILD_CPPFLAGS := -D__KERNEL__
		KBUILD_RUSTFLAGS := $(rust_common_flags) \
		@@ -824,10 +815,6 @@ endif # may-sync-config
		endif # need-config

		KBUILD_CFLAGS += -fno-delete-null-pointer-checks
		KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,)
		KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation)
		KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow)
		KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)

		ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
		KBUILD_CFLAGS += -O2
		@@ -858,40 +845,15 @@ ifdef CONFIG_READABLE_ASM
		KBUILD_CFLAGS += -fno-reorder-blocks -fno-ipa-cp-clone -fno-partial-inlining
		endif

		ifneq ($(CONFIG_FRAME_WARN),0)
		KBUILD_CFLAGS += -Wframe-larger-than=$(CONFIG_FRAME_WARN)
		endif

		stackp-flags-y := -fno-stack-protector
		stackp-flags-$(CONFIG_STACKPROTECTOR) := -fstack-protector
		stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong

		KBUILD_CFLAGS += $(stackp-flags-y)

		KBUILD_CPPFLAGS-$(CONFIG_WERROR) += -Werror
		KBUILD_CPPFLAGS += $(KBUILD_CPPFLAGS-y)
		KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds

		KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings
		KBUILD_RUSTFLAGS += $(KBUILD_RUSTFLAGS-y)

		ifdef CONFIG_CC_IS_CLANG
		# The kernel builds with '-std=gnu11' so use of GNU extensions is acceptable.
		KBUILD_CFLAGS += -Wno-gnu
		else

		# gcc inanely warns about local variables called 'main'
		KBUILD_CFLAGS += -Wno-main
		endif

		# These warnings generated too much noise in a regular build.
		# Use make W=1 to enable them (see scripts/Makefile.extrawarn)
		KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
		KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)

		# These result in bogus false positives
		KBUILD_CFLAGS += $(call cc-disable-warning, dangling-pointer)

		ifdef CONFIG_FRAME_POINTER
		KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls
		KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
		@@ -1026,51 +988,12 @@ endif
		# arch Makefile may override CC so keep this after arch Makefile is included
		NOSTDINC_FLAGS += -nostdinc

		# Variable Length Arrays (VLAs) should not be used anywhere in the kernel
		KBUILD_CFLAGS += -Wvla

		# disable pointer signed / unsigned warnings in gcc 4.0
		KBUILD_CFLAGS += -Wno-pointer-sign

		# In order to make sure new function cast mismatches are not introduced
		# in the kernel (to avoid tripping CFI checking), the kernel should be
		# globally built with -Wcast-function-type.
		KBUILD_CFLAGS += $(call cc-option, -Wcast-function-type)

		# To gain proper coverage for CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE,
		# the kernel uses only C99 flexible arrays for dynamically sized trailing
		# arrays. Enforce this for everything that may examine structure sizes and
		# perform bounds checking.
		KBUILD_CFLAGS += $(call cc-option, -fstrict-flex-arrays=3)

		# disable stringop warnings in gcc 8+
		KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)

		# We'll want to enable this eventually, but it's not going away for 5.7 at least
		KBUILD_CFLAGS += $(call cc-disable-warning, stringop-overflow)

		# Another good warning that we'll want to enable eventually
		KBUILD_CFLAGS += $(call cc-disable-warning, restrict)

		# Enabled with W=2, disabled by default as noisy
		ifdef CONFIG_CC_IS_GCC
		KBUILD_CFLAGS += -Wno-maybe-uninitialized
		endif

		# The allocators already balk at large sizes, so silence the compiler
		# warnings for bounds checks involving those possible values. While
		# -Wno-alloc-size-larger-than would normally be used here, earlier versions
		# of gcc (<9.1) weirdly don't handle the option correctly when _other_
		# warnings are produced (?!). Using -Walloc-size-larger-than=SIZE_MAX
		# doesn't work (as it is documented to), silently resolving to "0" prior to
		# version 9.1 (and producing an error more recently). Numeric values larger
		# than PTRDIFF_MAX also don't work prior to version 9.1, which are silently
		# ignored, continuing to default to PTRDIFF_MAX. So, left with no other
		# choice, we must perform a versioned check to disable this warning.
		# https://lore.kernel.org/lkml/20210824115859.187f272f@canb.auug.org.au
		KBUILD_CFLAGS-$(call gcc-min-version, 90100) += -Wno-alloc-size-larger-than
		KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)

		# disable invalid "can't wrap" optimizations for signed / pointers
		KBUILD_CFLAGS += -fno-strict-overflow

		@@ -1082,15 +1005,6 @@ ifdef CONFIG_CC_IS_GCC
		KBUILD_CFLAGS += -fconserve-stack
		endif

		# Prohibit date/time macros, which would make the build non-deterministic
		KBUILD_CFLAGS += -Werror=date-time

		# enforce correct pointer usage
		KBUILD_CFLAGS += $(call cc-option,-Werror=incompatible-pointer-types)

		# Require designated initializers for all marked structures
		KBUILD_CFLAGS += $(call cc-option,-Werror=designated-init)

		# change __FILE__ to the relative path from the srctree
		KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)

		@@ -1548,44 +1462,8 @@ modules: modules_prepare
		modules_prepare: prepare
		$(Q)$(MAKE) $(build)=scripts scripts/module.lds

		export modules_sign_only :=

		ifeq ($(CONFIG_MODULE_SIG),y)
		PHONY += modules_sign
		modules_sign: modules_install
		@:

		# modules_sign is a subset of modules_install.
		# 'make modules_install modules_sign' is equivalent to 'make modules_install'.
		ifeq ($(filter modules_install,$(MAKECMDGOALS)),)
		modules_sign_only := y
		endif
		endif

		endif # CONFIG_MODULES

		modinst_pre :=
		ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
		modinst_pre := __modinst_pre
		endif

		modules_install: $(modinst_pre)
		PHONY += __modinst_pre
		__modinst_pre:
		@rm -rf $(MODLIB)/kernel
		@rm -f $(MODLIB)/source
		@mkdir -p $(MODLIB)
		ifdef CONFIG_MODULES
		@ln -s $(abspath $(srctree)) $(MODLIB)/source
		@if [ ! $(objtree) -ef $(MODLIB)/build ]; then \
		rm -f $(MODLIB)/build ; \
		ln -s $(CURDIR) $(MODLIB)/build ; \
		fi
		@sed 's:^$.*$\.o$$:kernel/\1.ko:' modules.order > $(MODLIB)/modules.order
		endif
		@cp -f modules.builtin $(MODLIB)/
		@cp -f $(objtree)/modules.builtin.modinfo $(MODLIB)/

		###
		# Cleaning is done on three levels.
		# make clean Delete most generated files
		@@ -1594,7 +1472,7 @@ endif
		# make distclean Remove editor backup files, patch leftover files and the like

		# Directories & files removed with 'make clean'
		CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \
		CLEAN_FILES += vmlinux.symvers modules-only.symvers \
		modules.builtin modules.builtin.modinfo modules.nsdeps \
		compile_commands.json .thinlto-cache rust/test rust/doc \
		rust-project.json .vmlinux.objs .vmlinux.export.c
		@@ -1608,7 +1486,7 @@ MRPROPER_FILES += include/config include/generated \
		certs/signing_key.pem \
		certs/x509.genkey \
		vmlinux-gdb.py \
		*.spec rpmbuild \
		kernel.spec rpmbuild \
		rust/libmacros.so

		# clean - Delete most, but leave enough to build external modules
		@@ -1675,7 +1553,6 @@ help:
		@echo ' mrproper - Remove all generated files + config + various backup files'
		@echo ' distclean - mrproper + remove editor backup and patch files'
		@echo ''
		@echo 'Configuration targets:'
		@$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
		@echo ''
		@echo 'Other generic targets:'
		@@ -1923,19 +1800,39 @@ help:
		@echo ' rust-analyzer - generate rust-project.json rust-analyzer support file'
		@echo ''

		ifndef CONFIG_MODULES
		modules modules_install: __external_modules_error
		__external_modules_error:
		@echo >&2 '***'
		@echo >&2 '*** The present kernel disabled CONFIG_MODULES.'
		@echo >&2 '*** You cannot build or install external modules.'
		@echo >&2 '***'
		@false
		endif

		endif # KBUILD_EXTMOD

		# ---------------------------------------------------------------------------
		# Modules

		PHONY += modules modules_install modules_prepare
		PHONY += modules modules_install modules_sign modules_prepare

		modules_install:
		$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst \
		sign-only=$(if $(filter modules_install,$(MAKECMDGOALS)),,y)

		ifeq ($(CONFIG_MODULE_SIG),y)
		# modules_sign is a subset of modules_install.
		# 'make modules_install modules_sign' is equivalent to 'make modules_install'.
		modules_sign: modules_install
		@:
		else
		modules_sign:
		@echo >&2 '***'
		@echo >&2 '*** CONFIG_MODULE_SIG is disabled. You cannot sign modules.'
		@echo >&2 '***'
		@false
		endif

		ifdef CONFIG_MODULES

		@@ -1953,22 +1850,9 @@ PHONY += modules_check
		modules_check: $(MODORDER)
		$(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh $<

		quiet_cmd_depmod = DEPMOD $(MODLIB)
		cmd_depmod = $(CONFIG_SHELL) $(srctree)/scripts/depmod.sh $(DEPMOD) \
		$(KERNELRELEASE)

		modules_install:
		$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst
		$(call cmd,depmod)

		else # CONFIG_MODULES

		# Modules not configured
		# ---------------------------------------------------------------------------

		PHONY += __external_modules_error

		modules modules_install: __external_modules_error
		modules:
		@:

		KBUILD_MODULES :=
		@@ -2147,6 +2031,10 @@ kernelversion:
		image_name:
		@echo $(KBUILD_IMAGE)

		PHONY += run-command
		run-command:
		$(Q)$(KBUILD_RUN_COMMAND)

		quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN $(wildcard $(rm-files)))
		cmd_rmfiles = rm -rf $(rm-files)