Files
linux-stable-mirror/scripts/Makefile.lib
Kees Cook 0cecd37dae gcc-plugins: Force full rebuild when plugins change
There was no dependency between the plugins changing and the rest of the
kernel being built. This could cause strange behaviors as instrumentation
could vary between targets depending on when they were built.

Generate a new header file, gcc-plugins.h, any time the GCC plugins
change. Include the header file in compiler-version.h when its associated
feature name, GCC_PLUGINS, is defined. This will be picked up by fixdep
and force rebuilds where needed.

Add a generic "touch" kbuild command, which will be used again in
a following patch. Add a "normalize_path" string helper to make the
"TOUCH" output less ugly.

Link: https://lore.kernel.org/r/20250503184623.2572355-1-kees@kernel.org
Tested-by: Nicolas Schier <n.schier@avm.de>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Kees Cook <kees@kernel.org>
2025-05-08 09:42:06 -07:00

573 lines
21 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
# flags that take effect in current and sub directories
KBUILD_AFLAGS += $(subdir-asflags-y)
KBUILD_CFLAGS += $(subdir-ccflags-y)
KBUILD_RUSTFLAGS += $(subdir-rustflags-y)
# Figure out what we need to build from the various variables
# ===========================================================================
# When an object is listed to be built compiled-in and modular,
# only build the compiled-in version
obj-m := $(filter-out $(obj-y),$(obj-m))
# Libraries are always collected in one lib file.
# Filter out objects already built-in
lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m)))
# Subdirectories we need to descend into
subdir-ym := $(sort $(subdir-y) $(subdir-m) \
$(patsubst %/,%, $(filter %/, $(obj-y) $(obj-m))))
# Handle objects in subdirs:
# - If we encounter foo/ in $(obj-y), replace it by foo/built-in.a and
# foo/modules.order
# - If we encounter foo/ in $(obj-m), replace it by foo/modules.order
#
# Generate modules.order to determine modorder. Unfortunately, we don't have
# information about ordering between -y and -m subdirs. Just put -y's first.
ifdef need-modorder
obj-m := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m))
else
obj-m := $(filter-out %/, $(obj-m))
endif
ifdef need-builtin
obj-y := $(patsubst %/, %/built-in.a, $(obj-y))
else
obj-y := $(filter-out %/, $(obj-y))
endif
# Expand $(foo-objs) $(foo-y) etc. by replacing their individuals
suffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s))))
# List composite targets that are constructed by combining other targets
multi-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $m)))
# List primitive targets that are compiled from source files
real-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $(call suffix-search, $m, $2, $3), $m))
# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
multi-obj-y := $(call multi-search, $(obj-y), .o, -objs -y)
multi-obj-m := $(call multi-search, $(obj-m), .o, -objs -y -m)
multi-obj-ym := $(multi-obj-y) $(multi-obj-m)
# Replace multi-part objects by their individual parts,
# including built-in.a from subdirectories
real-obj-y := $(call real-search, $(obj-y), .o, -objs -y)
real-obj-m := $(call real-search, $(obj-m), .o, -objs -y -m)
always-y += $(always-m)
# hostprogs-always-y += foo
# ... is a shorthand for
# hostprogs += foo
# always-y += foo
hostprogs += $(hostprogs-always-y) $(hostprogs-always-m)
always-y += $(hostprogs-always-y) $(hostprogs-always-m)
# userprogs-always-y is likewise.
userprogs += $(userprogs-always-y) $(userprogs-always-m)
always-y += $(userprogs-always-y) $(userprogs-always-m)
# Add subdir path
ifneq ($(obj),.)
extra-y := $(addprefix $(obj)/,$(extra-y))
always-y := $(addprefix $(obj)/,$(always-y))
targets := $(addprefix $(obj)/,$(targets))
obj-m := $(addprefix $(obj)/,$(obj-m))
lib-y := $(addprefix $(obj)/,$(lib-y))
real-obj-y := $(addprefix $(obj)/,$(real-obj-y))
real-obj-m := $(addprefix $(obj)/,$(real-obj-m))
multi-obj-m := $(addprefix $(obj)/, $(multi-obj-m))
subdir-ym := $(addprefix $(obj)/,$(subdir-ym))
endif
# Finds the multi-part object the current object will be linked into.
# If the object belongs to two or more multi-part objects, list them all.
modname-multi = $(sort $(foreach m,$(multi-obj-ym),\
$(if $(filter $*.o, $(call suffix-search, $m, .o, -objs -y -m)),$(m:.o=))))
__modname = $(or $(modname-multi),$(basetarget))
modname = $(subst $(space),:,$(__modname))
modfile = $(addprefix $(obj)/,$(__modname))
# target with $(obj)/ and its suffix stripped
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-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,$(modname)) \
-D__KBUILD_MODNAME=kmod_$(call name-fix-token,$(modname))
modfile_flags = -DKBUILD_MODFILE=$(call stringify,$(modfile))
_c_flags = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \
$(filter-out $(ccflags-remove-y), \
$(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(ccflags-y)) \
$(CFLAGS_$(target-stem).o))
_rust_flags = $(filter-out $(RUSTFLAGS_REMOVE_$(target-stem).o), \
$(filter-out $(rustflags-remove-y), \
$(KBUILD_RUSTFLAGS) $(rustflags-y)) \
$(RUSTFLAGS_$(target-stem).o))
_a_flags = $(filter-out $(AFLAGS_REMOVE_$(target-stem).o), \
$(filter-out $(asflags-remove-y), \
$(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(asflags-y)) \
$(AFLAGS_$(target-stem).o))
_cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(target-stem).lds)
#
# Enable gcov profiling flags for a file, directory or for all files depending
# on variables GCOV_PROFILE_obj.o, GCOV_PROFILE and CONFIG_GCOV_PROFILE_ALL
# (in this order)
#
ifeq ($(CONFIG_GCOV_KERNEL),y)
_c_flags += $(if $(patsubst n%,, \
$(GCOV_PROFILE_$(target-stem).o)$(GCOV_PROFILE)$(if $(is-kernel-object),$(CONFIG_GCOV_PROFILE_ALL))), \
$(CFLAGS_GCOV))
endif
#
# Enable address sanitizer flags for kernel except some files or directories
# we don't want to check (depends on variables KASAN_SANITIZE_obj.o, KASAN_SANITIZE)
#
ifeq ($(CONFIG_KASAN),y)
ifneq ($(CONFIG_KASAN_HW_TAGS),y)
_c_flags += $(if $(patsubst n%,, \
$(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
$(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
_rust_flags += $(if $(patsubst n%,, \
$(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
$(RUSTFLAGS_KASAN))
endif
endif
ifeq ($(CONFIG_KMSAN),y)
_c_flags += $(if $(patsubst n%,, \
$(KMSAN_SANITIZE_$(target-stem).o)$(KMSAN_SANITIZE)$(is-kernel-object)), \
$(CFLAGS_KMSAN))
_c_flags += $(if $(patsubst n%,, \
$(KMSAN_ENABLE_CHECKS_$(target-stem).o)$(KMSAN_ENABLE_CHECKS)$(is-kernel-object)), \
, -mllvm -msan-disable-checks=1)
endif
ifeq ($(CONFIG_UBSAN),y)
_c_flags += $(if $(patsubst n%,, \
$(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_SANITIZE)$(is-kernel-object)), \
$(CFLAGS_UBSAN))
_c_flags += $(if $(patsubst n%,, \
$(UBSAN_INTEGER_WRAP_$(target-stem).o)$(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_INTEGER_WRAP)$(UBSAN_SANITIZE)$(is-kernel-object)), \
$(CFLAGS_UBSAN_INTEGER_WRAP))
endif
ifeq ($(CONFIG_KCOV),y)
_c_flags += $(if $(patsubst n%,, \
$(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(if $(is-kernel-object),$(CONFIG_KCOV_INSTRUMENT_ALL))), \
$(CFLAGS_KCOV))
endif
#
# Enable KCSAN flags except some files or directories we don't want to check
# (depends on variables KCSAN_SANITIZE_obj.o, KCSAN_SANITIZE)
#
ifeq ($(CONFIG_KCSAN),y)
_c_flags += $(if $(patsubst n%,, \
$(KCSAN_SANITIZE_$(target-stem).o)$(KCSAN_SANITIZE)$(is-kernel-object)), \
$(CFLAGS_KCSAN))
# Some uninstrumented files provide implied barriers required to avoid false
# positives: set KCSAN_INSTRUMENT_BARRIERS for barrier instrumentation only.
_c_flags += $(if $(patsubst n%,, \
$(KCSAN_INSTRUMENT_BARRIERS_$(target-stem).o)$(KCSAN_INSTRUMENT_BARRIERS)n), \
-D__KCSAN_INSTRUMENT_BARRIERS__)
endif
#
# Enable AutoFDO build flags except some files or directories we don't want to
# enable (depends on variables AUTOFDO_PROFILE_obj.o and AUTOFDO_PROFILE).
#
ifeq ($(CONFIG_AUTOFDO_CLANG),y)
_c_flags += $(if $(patsubst n%,, \
$(AUTOFDO_PROFILE_$(target-stem).o)$(AUTOFDO_PROFILE)$(is-kernel-object)), \
$(CFLAGS_AUTOFDO_CLANG))
endif
#
# Enable Propeller build flags except some files or directories we don't want to
# enable (depends on variables AUTOFDO_PROPELLER_obj.o and PROPELLER_PROFILE).
#
ifdef CONFIG_PROPELLER_CLANG
_c_flags += $(if $(patsubst n%,, \
$(AUTOFDO_PROFILE_$(target-stem).o)$(AUTOFDO_PROFILE)$(PROPELLER_PROFILE))$(is-kernel-object), \
$(CFLAGS_PROPELLER_CLANG))
endif
# $(src) for including checkin headers from generated source files
# $(obj) for including generated headers from checkin source files
ifdef building_out_of_srctree
_c_flags += $(addprefix -I, $(src) $(obj))
_a_flags += $(addprefix -I, $(src) $(obj))
_cpp_flags += $(addprefix -I, $(src) $(obj))
endif
# If $(is-kernel-object) is 'y', this object will be linked to vmlinux or modules
is-kernel-object = $(or $(part-of-builtin),$(part-of-module))
part-of-builtin = $(if $(filter $(basename $@).o, $(real-obj-y) $(lib-y)),y)
part-of-module = $(if $(filter $(basename $@).o, $(real-obj-m)),y)
quiet_modtag = $(if $(part-of-module),[M], )
modkern_cflags = \
$(if $(part-of-module), \
$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL) $(modfile_flags))
modkern_rustflags = \
$(if $(part-of-module), \
$(KBUILD_RUSTFLAGS_MODULE) $(RUSTFLAGS_MODULE), \
$(KBUILD_RUSTFLAGS_KERNEL) $(RUSTFLAGS_KERNEL))
modkern_aflags = $(if $(part-of-module), \
$(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE), \
$(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) $(modfile_flags))
c_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
-include $(srctree)/include/linux/compiler_types.h \
$(_c_flags) $(modkern_cflags) \
$(basename_flags) $(modname_flags)
rust_flags = $(_rust_flags) $(modkern_rustflags) @$(objtree)/include/generated/rustc_cfg
a_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(_a_flags) $(modkern_aflags) $(modname_flags)
cpp_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(_cpp_flags)
ld_flags = $(KBUILD_LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F))
ifdef CONFIG_OBJTOOL
objtool := $(objtree)/tools/objtool/objtool
objtool-args-$(CONFIG_HAVE_JUMP_LABEL_HACK) += --hacks=jump_label
objtool-args-$(CONFIG_HAVE_NOINSTR_HACK) += --hacks=noinstr
objtool-args-$(CONFIG_MITIGATION_CALL_DEPTH_TRACKING) += --hacks=skylake
objtool-args-$(CONFIG_X86_KERNEL_IBT) += --ibt
objtool-args-$(CONFIG_FINEIBT) += --cfi
objtool-args-$(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL) += --mcount
ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
objtool-args-$(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT) += --mnop
endif
objtool-args-$(CONFIG_UNWINDER_ORC) += --orc
objtool-args-$(CONFIG_MITIGATION_RETPOLINE) += --retpoline
objtool-args-$(CONFIG_MITIGATION_RETHUNK) += --rethunk
objtool-args-$(CONFIG_MITIGATION_SLS) += --sls
objtool-args-$(CONFIG_STACK_VALIDATION) += --stackval
objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE) += --static-call
objtool-args-$(CONFIG_HAVE_UACCESS_VALIDATION) += --uaccess
objtool-args-$(or $(CONFIG_GCOV_KERNEL),$(CONFIG_KCOV)) += --no-unreachable
objtool-args-$(CONFIG_PREFIX_SYMBOLS) += --prefix=$(CONFIG_FUNCTION_PADDING_BYTES)
objtool-args-$(CONFIG_OBJTOOL_WERROR) += --Werror
objtool-args = $(objtool-args-y) \
$(if $(delay-objtool), --link) \
$(if $(part-of-module), --module)
delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT))
cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool-args) $@)
cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
objtool-enabled := y
endif # CONFIG_OBJTOOL
# Useful for describing the dependency of composite objects
# Usage:
# $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add)
define multi_depend
$(foreach m, $1, \
$(eval $m: \
$(addprefix $(obj)/, $(call suffix-search, $(patsubst $(obj)/%,%,$m), $2, $3))))
endef
# Remove ".." and "." from a path, without using "realpath"
# Usage:
# $(call normalize_path,path/to/../file)
define normalize_path
$(strip $(eval elements :=) \
$(foreach elem,$(subst /, ,$1), \
$(if $(filter-out .,$(elem)), \
$(if $(filter ..,$(elem)), \
$(eval elements := $(wordlist 2,$(words $(elements)),x $(elements))), \
$(eval elements := $(elements) $(elem))))) \
$(subst $(space),/,$(elements)))
endef
# Build commands
# ===========================================================================
# These are shared by some Makefile.* files.
ifdef CONFIG_LTO_CLANG
# Run $(LD) here to convert LLVM IR to ELF in the following cases:
# - when this object needs objtool processing, as objtool cannot process LLVM IR
# - when this is a single-object module, as modpost cannot process LLVM IR
cmd_ld_single = $(if $(objtool-enabled)$(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@)
endif
quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \
$(cmd_ld_single) \
$(cmd_objtool)
define rule_cc_o_c
$(call cmd_and_fixdep,cc_o_c)
$(call cmd,checksrc)
$(call cmd,checkdoc)
$(call cmd,gen_objtooldep)
$(call cmd,gen_symversions_c)
$(call cmd,record_mcount)
$(call cmd,warn_shared_object)
endef
quiet_cmd_as_o_S = AS $(quiet_modtag) $@
cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool)
define rule_as_o_S
$(call cmd_and_fixdep,as_o_S)
$(call cmd,gen_objtooldep)
$(call cmd,gen_symversions_S)
$(call cmd,warn_shared_object)
endef
# Copy a file
# ===========================================================================
# 'cp' preserves permissions. If you use it to copy a file in read-only srctree,
# the copy would be read-only as well, leading to an error when executing the
# rule next time. Use 'cat' instead in order to generate a writable file.
quiet_cmd_copy = COPY $@
cmd_copy = cat $< > $@
$(obj)/%: $(src)/%_shipped
$(call cmd,copy)
# Touch a file
# ===========================================================================
quiet_cmd_touch = TOUCH $(call normalize_path,$@)
cmd_touch = touch $@
# Commands useful for building a boot image
# ===========================================================================
#
# Use as following:
#
# target: source(s) FORCE
# $(if_changed,ld/objcopy/gzip)
#
# and add target to 'targets' so that we know we have to
# read in the saved command line
# Linking
# ---------------------------------------------------------------------------
quiet_cmd_ld = LD $@
cmd_ld = $(LD) $(ld_flags) $(real-prereqs) -o $@
# Archive
# ---------------------------------------------------------------------------
quiet_cmd_ar = AR $@
cmd_ar = rm -f $@; $(AR) cDPrsT $@ $(real-prereqs)
# Objcopy
# ---------------------------------------------------------------------------
quiet_cmd_objcopy = OBJCOPY $@
cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
# Gzip
# ---------------------------------------------------------------------------
quiet_cmd_gzip = GZIP $@
cmd_gzip = cat $(real-prereqs) | $(KGZIP) -n -f -9 > $@
# Bzip2
# ---------------------------------------------------------------------------
# Bzip2 and LZMA do not include size in file... so we have to fake that;
# append the size as a 32-bit littleendian number as gzip does.
size_append = printf $(shell \
dec_size=0; \
for F in $(real-prereqs); do \
fsize=$$($(CONFIG_SHELL) $(srctree)/scripts/file-size.sh $$F); \
dec_size=$$(expr $$dec_size + $$fsize); \
done; \
printf "%08x\n" $$dec_size | \
sed 's/\(..\)/\1 /g' | { \
read ch0 ch1 ch2 ch3; \
for ch in $$ch3 $$ch2 $$ch1 $$ch0; do \
printf '%s%03o' '\\' $$((0x$$ch)); \
done; \
} \
)
quiet_cmd_file_size = GEN $@
cmd_file_size = $(size_append) > $@
quiet_cmd_bzip2 = BZIP2 $@
cmd_bzip2 = cat $(real-prereqs) | $(KBZIP2) -9 > $@
quiet_cmd_bzip2_with_size = BZIP2 $@
cmd_bzip2_with_size = { cat $(real-prereqs) | $(KBZIP2) -9; $(size_append); } > $@
# Lzma
# ---------------------------------------------------------------------------
quiet_cmd_lzma = LZMA $@
cmd_lzma = cat $(real-prereqs) | $(LZMA) -9 > $@
quiet_cmd_lzma_with_size = LZMA $@
cmd_lzma_with_size = { cat $(real-prereqs) | $(LZMA) -9; $(size_append); } > $@
quiet_cmd_lzo = LZO $@
cmd_lzo = cat $(real-prereqs) | $(KLZOP) -9 > $@
quiet_cmd_lzo_with_size = LZO $@
cmd_lzo_with_size = { cat $(real-prereqs) | $(KLZOP) -9; $(size_append); } > $@
quiet_cmd_lz4 = LZ4 $@
cmd_lz4 = cat $(real-prereqs) | $(LZ4) -l -9 - - > $@
quiet_cmd_lz4_with_size = LZ4 $@
cmd_lz4_with_size = { cat $(real-prereqs) | $(LZ4) -l -9 - -; \
$(size_append); } > $@
# U-Boot mkimage
# ---------------------------------------------------------------------------
MKIMAGE := $(srctree)/scripts/mkuboot.sh
# SRCARCH just happens to match slightly more than ARCH (on sparc), so reduces
# the number of overrides in arch makefiles
UIMAGE_ARCH ?= $(SRCARCH)
UIMAGE_COMPRESSION ?= $(or $(2),none)
UIMAGE_OPTS-y ?=
UIMAGE_TYPE ?= kernel
UIMAGE_LOADADDR ?= arch_must_set_this
UIMAGE_ENTRYADDR ?= $(UIMAGE_LOADADDR)
UIMAGE_NAME ?= Linux-$(KERNELRELEASE)
quiet_cmd_uimage = UIMAGE $@
cmd_uimage = $(BASH) $(MKIMAGE) -A $(UIMAGE_ARCH) -O linux \
-C $(UIMAGE_COMPRESSION) $(UIMAGE_OPTS-y) \
-T $(UIMAGE_TYPE) \
-a $(UIMAGE_LOADADDR) -e $(UIMAGE_ENTRYADDR) \
-n '$(UIMAGE_NAME)' -d $< $@
# Flat Image Tree (FIT)
# This allows for packaging of a kernel and all devicetrees files, using
# compression.
# ---------------------------------------------------------------------------
MAKE_FIT := $(srctree)/scripts/make_fit.py
# Use this to override the compression algorithm
FIT_COMPRESSION ?= gzip
quiet_cmd_fit = FIT $@
cmd_fit = $(MAKE_FIT) -o $@ --arch $(UIMAGE_ARCH) --os linux \
--name '$(UIMAGE_NAME)' \
$(if $(findstring 1,$(KBUILD_VERBOSE)),-v) \
$(if $(FIT_DECOMPOSE_DTBS),--decompose-dtbs) \
--compress $(FIT_COMPRESSION) -k $< @$(word 2,$^)
# XZ
# ---------------------------------------------------------------------------
# Use xzkern or xzkern_with_size to compress the kernel image and xzmisc to
# compress other things.
#
# xzkern uses a big LZMA2 dictionary since it doesn't increase memory usage
# of the kernel decompressor. A BCJ filter is used if it is available for
# the target architecture.
#
# xzkern_with_size also appends uncompressed size of the data using
# size_append. The .xz format has the size information available at the end
# of the file too, but it's in more complex format and it's good to avoid
# changing the part of the boot code that reads the uncompressed size.
# Note that the bytes added by size_append will make the xz tool think that
# the file is corrupt. This is expected.
#
# xzmisc doesn't use size_append, so it can be used to create normal .xz
# files. xzmisc uses smaller LZMA2 dictionary than xzkern, because a very
# big dictionary would increase the memory usage too much in the multi-call
# decompression mode. A BCJ filter isn't used either.
quiet_cmd_xzkern = XZKERN $@
cmd_xzkern = cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh > $@
quiet_cmd_xzkern_with_size = XZKERN $@
cmd_xzkern_with_size = { cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh; \
$(size_append); } > $@
quiet_cmd_xzmisc = XZMISC $@
cmd_xzmisc = cat $(real-prereqs) | $(XZ) --check=crc32 --lzma2=dict=1MiB > $@
# ZSTD
# ---------------------------------------------------------------------------
# Appends the uncompressed size of the data using size_append. The .zst
# format has the size information available at the beginning of the file too,
# but it's in a more complex format and it's good to avoid changing the part
# of the boot code that reads the uncompressed size.
#
# Note that the bytes added by size_append will make the zstd tool think that
# the file is corrupt. This is expected.
#
# zstd uses a maximum window size of 8 MB. zstd22 uses a maximum window size of
# 128 MB. zstd22 is used for kernel compression because it is decompressed in a
# single pass, so zstd doesn't need to allocate a window buffer. When streaming
# decompression is used, like initramfs decompression, zstd22 should likely not
# be used because it would require zstd to allocate a 128 MB buffer.
quiet_cmd_zstd = ZSTD $@
cmd_zstd = cat $(real-prereqs) | $(ZSTD) -19 > $@
quiet_cmd_zstd22 = ZSTD22 $@
cmd_zstd22 = cat $(real-prereqs) | $(ZSTD) -22 --ultra > $@
quiet_cmd_zstd22_with_size = ZSTD22 $@
cmd_zstd22_with_size = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@
# ASM offsets
# ---------------------------------------------------------------------------
# Default sed regexp - multiline due to syntax constraints
#
# Use [:space:] because LLVM's integrated assembler inserts <tab> around
# the .ascii directive whereas GCC keeps the <space> as-is.
define sed-offsets
's:^[[:space:]]*\.ascii[[:space:]]*"\(.*\)".*:\1:; \
/^->/{s:->#\(.*\):/* \1 */:; \
s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
s:->::; p;}'
endef
# Use filechk to avoid rebuilds when a header changes, but the resulting file
# does not
define filechk_offsets
echo "#ifndef $2"; \
echo "#define $2"; \
echo "/*"; \
echo " * DO NOT MODIFY."; \
echo " *"; \
echo " * This file was generated by Kbuild"; \
echo " */"; \
echo ""; \
sed -ne $(sed-offsets) < $<; \
echo ""; \
echo "#endif"
endef