linux/scripts/Makefile.lib
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   1# SPDX-License-Identifier: GPL-2.0
   2# Backward compatibility
   3asflags-y  += $(EXTRA_AFLAGS)
   4ccflags-y  += $(EXTRA_CFLAGS)
   5cppflags-y += $(EXTRA_CPPFLAGS)
   6ldflags-y  += $(EXTRA_LDFLAGS)
   7
   8# flags that take effect in current and sub directories
   9KBUILD_AFLAGS += $(subdir-asflags-y)
  10KBUILD_CFLAGS += $(subdir-ccflags-y)
  11
  12# Figure out what we need to build from the various variables
  13# ===========================================================================
  14
  15# When an object is listed to be built compiled-in and modular,
  16# only build the compiled-in version
  17obj-m := $(filter-out $(obj-y),$(obj-m))
  18
  19# Libraries are always collected in one lib file.
  20# Filter out objects already built-in
  21lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m)))
  22
  23# Subdirectories we need to descend into
  24subdir-ym := $(sort $(subdir-y) $(subdir-m) \
  25                        $(patsubst %/,%, $(filter %/, $(obj-y) $(obj-m))))
  26
  27# Handle objects in subdirs:
  28# - If we encounter foo/ in $(obj-y), replace it by foo/built-in.a and
  29#   foo/modules.order
  30# - If we encounter foo/ in $(obj-m), replace it by foo/modules.order
  31#
  32# Generate modules.order to determine modorder. Unfortunately, we don't have
  33# information about ordering between -y and -m subdirs. Just put -y's first.
  34
  35ifdef need-modorder
  36obj-m := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m))
  37else
  38obj-m := $(filter-out %/, $(obj-m))
  39endif
  40
  41ifdef need-builtin
  42obj-y           := $(patsubst %/, %/built-in.a, $(obj-y))
  43else
  44obj-y           := $(filter-out %/, $(obj-y))
  45endif
  46
  47# Expand $(foo-objs) $(foo-y) etc. by replacing their individuals
  48suffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s))))
  49# List composite targets that are constructed by combining other targets
  50multi-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $m)))
  51# List primitive targets that are compiled from source files
  52real-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $(call suffix-search, $m, $2, $3), $m))
  53
  54# If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
  55multi-obj-y := $(call multi-search, $(obj-y), .o, -objs -y)
  56multi-obj-m := $(call multi-search, $(obj-m), .o, -objs -y -m)
  57multi-obj-ym := $(multi-obj-y) $(multi-obj-m)
  58
  59# Replace multi-part objects by their individual parts,
  60# including built-in.a from subdirectories
  61real-obj-y := $(call real-search, $(obj-y), .o, -objs -y)
  62real-obj-m := $(call real-search, $(obj-m), .o, -objs -y -m)
  63
  64always-y += $(always-m)
  65
  66# hostprogs-always-y += foo
  67# ... is a shorthand for
  68# hostprogs += foo
  69# always-y  += foo
  70hostprogs += $(hostprogs-always-y) $(hostprogs-always-m)
  71always-y += $(hostprogs-always-y) $(hostprogs-always-m)
  72
  73# userprogs-always-y is likewise.
  74userprogs += $(userprogs-always-y) $(userprogs-always-m)
  75always-y += $(userprogs-always-y) $(userprogs-always-m)
  76
  77# DTB
  78# If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built
  79dtb-$(CONFIG_OF_ALL_DTBS)       += $(dtb-)
  80
  81# Composite DTB (i.e. DTB constructed by overlay)
  82multi-dtb-y := $(call multi-search, $(dtb-y), .dtb, -dtbs)
  83# Primitive DTB compiled from *.dts
  84real-dtb-y := $(call real-search, $(dtb-y), .dtb, -dtbs)
  85# Base DTB that overlay is applied onto (each first word of $(*-dtbs) expansion)
  86base-dtb-y := $(foreach m, $(multi-dtb-y), $(firstword $(call suffix-search, $m, .dtb, -dtbs)))
  87
  88always-y                        += $(dtb-y)
  89
  90ifneq ($(CHECK_DTBS),)
  91always-y += $(patsubst %.dtb,%.dt.yaml, $(real-dtb-y))
  92always-y += $(patsubst %.dtbo,%.dt.yaml, $(real-dtb-y))
  93endif
  94
  95# Add subdir path
  96
  97extra-y         := $(addprefix $(obj)/,$(extra-y))
  98always-y        := $(addprefix $(obj)/,$(always-y))
  99targets         := $(addprefix $(obj)/,$(targets))
 100obj-m           := $(addprefix $(obj)/,$(obj-m))
 101lib-y           := $(addprefix $(obj)/,$(lib-y))
 102real-obj-y      := $(addprefix $(obj)/,$(real-obj-y))
 103real-obj-m      := $(addprefix $(obj)/,$(real-obj-m))
 104multi-obj-m     := $(addprefix $(obj)/, $(multi-obj-m))
 105multi-dtb-y     := $(addprefix $(obj)/, $(multi-dtb-y))
 106real-dtb-y      := $(addprefix $(obj)/, $(real-dtb-y))
 107subdir-ym       := $(addprefix $(obj)/,$(subdir-ym))
 108
 109# Finds the multi-part object the current object will be linked into.
 110# If the object belongs to two or more multi-part objects, list them all.
 111modname-multi = $(sort $(foreach m,$(multi-obj-ym),\
 112                $(if $(filter $*.o, $(call suffix-search, $m, .o, -objs -y -m)),$(m:.o=))))
 113
 114__modname = $(if $(modname-multi),$(modname-multi),$(basetarget))
 115
 116modname = $(subst $(space),:,$(__modname))
 117modfile = $(addprefix $(obj)/,$(__modname))
 118
 119# target with $(obj)/ and its suffix stripped
 120target-stem = $(basename $(patsubst $(obj)/%,%,$@))
 121
 122# These flags are needed for modversions and compiling, so we define them here
 123# $(modname_flags) defines KBUILD_MODNAME as the name of the module it will
 124# end up in (or would, if it gets compiled in)
 125name-fix-token = $(subst $(comma),_,$(subst -,_,$1))
 126name-fix = $(call stringify,$(call name-fix-token,$1))
 127basename_flags = -DKBUILD_BASENAME=$(call name-fix,$(basetarget))
 128modname_flags  = -DKBUILD_MODNAME=$(call name-fix,$(modname)) \
 129                 -D__KBUILD_MODNAME=kmod_$(call name-fix-token,$(modname))
 130modfile_flags  = -DKBUILD_MODFILE=$(call stringify,$(modfile))
 131
 132_c_flags       = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \
 133                     $(filter-out $(ccflags-remove-y), \
 134                         $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(ccflags-y)) \
 135                     $(CFLAGS_$(target-stem).o))
 136_a_flags       = $(filter-out $(AFLAGS_REMOVE_$(target-stem).o), \
 137                     $(filter-out $(asflags-remove-y), \
 138                         $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(asflags-y)) \
 139                     $(AFLAGS_$(target-stem).o))
 140_cpp_flags     = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(target-stem).lds)
 141
 142#
 143# Enable gcov profiling flags for a file, directory or for all files depending
 144# on variables GCOV_PROFILE_obj.o, GCOV_PROFILE and CONFIG_GCOV_PROFILE_ALL
 145# (in this order)
 146#
 147ifeq ($(CONFIG_GCOV_KERNEL),y)
 148_c_flags += $(if $(patsubst n%,, \
 149                $(GCOV_PROFILE_$(basetarget).o)$(GCOV_PROFILE)$(CONFIG_GCOV_PROFILE_ALL)), \
 150                $(CFLAGS_GCOV))
 151endif
 152
 153#
 154# Enable address sanitizer flags for kernel except some files or directories
 155# we don't want to check (depends on variables KASAN_SANITIZE_obj.o, KASAN_SANITIZE)
 156#
 157ifeq ($(CONFIG_KASAN),y)
 158ifneq ($(CONFIG_KASAN_HW_TAGS),y)
 159_c_flags += $(if $(patsubst n%,, \
 160                $(KASAN_SANITIZE_$(basetarget).o)$(KASAN_SANITIZE)y), \
 161                $(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
 162endif
 163endif
 164
 165ifeq ($(CONFIG_UBSAN),y)
 166_c_flags += $(if $(patsubst n%,, \
 167                $(UBSAN_SANITIZE_$(basetarget).o)$(UBSAN_SANITIZE)$(CONFIG_UBSAN_SANITIZE_ALL)), \
 168                $(CFLAGS_UBSAN))
 169endif
 170
 171ifeq ($(CONFIG_KCOV),y)
 172_c_flags += $(if $(patsubst n%,, \
 173        $(KCOV_INSTRUMENT_$(basetarget).o)$(KCOV_INSTRUMENT)$(CONFIG_KCOV_INSTRUMENT_ALL)), \
 174        $(CFLAGS_KCOV))
 175endif
 176
 177#
 178# Enable KCSAN flags except some files or directories we don't want to check
 179# (depends on variables KCSAN_SANITIZE_obj.o, KCSAN_SANITIZE)
 180#
 181ifeq ($(CONFIG_KCSAN),y)
 182_c_flags += $(if $(patsubst n%,, \
 183        $(KCSAN_SANITIZE_$(basetarget).o)$(KCSAN_SANITIZE)y), \
 184        $(CFLAGS_KCSAN))
 185endif
 186
 187# $(srctree)/$(src) for including checkin headers from generated source files
 188# $(objtree)/$(obj) for including generated headers from checkin source files
 189ifeq ($(KBUILD_EXTMOD),)
 190ifdef building_out_of_srctree
 191_c_flags   += -I $(srctree)/$(src) -I $(objtree)/$(obj)
 192_a_flags   += -I $(srctree)/$(src) -I $(objtree)/$(obj)
 193_cpp_flags += -I $(srctree)/$(src) -I $(objtree)/$(obj)
 194endif
 195endif
 196
 197part-of-module = $(if $(filter $(basename $@).o, $(real-obj-m)),y)
 198quiet_modtag = $(if $(part-of-module),[M],   )
 199
 200modkern_cflags =                                          \
 201        $(if $(part-of-module),                           \
 202                $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
 203                $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL) $(modfile_flags))
 204
 205modkern_aflags = $(if $(part-of-module),                                \
 206                        $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE),       \
 207                        $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL))
 208
 209c_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 210                 -include $(srctree)/include/linux/compiler_types.h       \
 211                 $(_c_flags) $(modkern_cflags)                           \
 212                 $(basename_flags) $(modname_flags)
 213
 214a_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 215                 $(_a_flags) $(modkern_aflags)
 216
 217cpp_flags      = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 218                 $(_cpp_flags)
 219
 220ld_flags       = $(KBUILD_LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F))
 221
 222DTC_INCLUDE    := $(srctree)/scripts/dtc/include-prefixes
 223
 224dtc_cpp_flags  = -Wp,-MMD,$(depfile).pre.tmp -nostdinc                    \
 225                 $(addprefix -I,$(DTC_INCLUDE))                          \
 226                 -undef -D__DTS__
 227
 228# Objtool arguments are also needed for modfinal with LTO, so we define
 229# then here to avoid duplication.
 230objtool_args =                                                          \
 231        $(if $(CONFIG_UNWINDER_ORC),orc generate,check)                 \
 232        $(if $(part-of-module), --module,)                              \
 233        $(if $(CONFIG_FRAME_POINTER),, --no-fp)                         \
 234        $(if $(or $(CONFIG_GCOV_KERNEL),$(CONFIG_LTO_CLANG)),           \
 235                --no-unreachable,)                                      \
 236        $(if $(CONFIG_RETPOLINE), --retpoline,)                         \
 237        $(if $(CONFIG_X86_SMAP), --uaccess,)                            \
 238        $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount,)
 239
 240# Useful for describing the dependency of composite objects
 241# Usage:
 242#   $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add)
 243define multi_depend
 244$(foreach m, $(notdir $1), \
 245        $(eval $(obj)/$m: \
 246        $(addprefix $(obj)/, $(foreach s, $3, $($(m:%$(strip $2)=%$(s)))))))
 247endef
 248
 249quiet_cmd_copy = COPY    $@
 250      cmd_copy = cp $< $@
 251
 252# Shipped files
 253# ===========================================================================
 254# 'cp' preserves permissions. If you use it to copy a file in read-only srctree,
 255# the copy would be read-only as well, leading to an error when executing the
 256# rule next time. Use 'cat' instead in order to generate a writable file.
 257
 258quiet_cmd_shipped = SHIPPED $@
 259cmd_shipped = cat $< > $@
 260
 261$(obj)/%: $(src)/%_shipped
 262        $(call cmd,shipped)
 263
 264# Commands useful for building a boot image
 265# ===========================================================================
 266#
 267#       Use as following:
 268#
 269#       target: source(s) FORCE
 270#               $(if_changed,ld/objcopy/gzip)
 271#
 272#       and add target to 'targets' so that we know we have to
 273#       read in the saved command line
 274
 275# Linking
 276# ---------------------------------------------------------------------------
 277
 278quiet_cmd_ld = LD      $@
 279      cmd_ld = $(LD) $(ld_flags) $(real-prereqs) -o $@
 280
 281# Archive
 282# ---------------------------------------------------------------------------
 283
 284quiet_cmd_ar = AR      $@
 285      cmd_ar = rm -f $@; $(AR) cDPrsT $@ $(real-prereqs)
 286
 287# Objcopy
 288# ---------------------------------------------------------------------------
 289
 290quiet_cmd_objcopy = OBJCOPY $@
 291cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
 292
 293# Gzip
 294# ---------------------------------------------------------------------------
 295
 296quiet_cmd_gzip = GZIP    $@
 297      cmd_gzip = cat $(real-prereqs) | $(KGZIP) -n -f -9 > $@
 298
 299# DTC
 300# ---------------------------------------------------------------------------
 301DTC ?= $(objtree)/scripts/dtc/dtc
 302DTC_FLAGS += -Wno-interrupt_provider
 303
 304# Disable noisy checks by default
 305ifeq ($(findstring 1,$(KBUILD_EXTRA_WARN)),)
 306DTC_FLAGS += -Wno-unit_address_vs_reg \
 307        -Wno-unit_address_format \
 308        -Wno-avoid_unnecessary_addr_size \
 309        -Wno-alias_paths \
 310        -Wno-graph_child_address \
 311        -Wno-simple_bus_reg \
 312        -Wno-unique_unit_address \
 313        -Wno-pci_device_reg
 314endif
 315
 316ifneq ($(findstring 2,$(KBUILD_EXTRA_WARN)),)
 317DTC_FLAGS += -Wnode_name_chars_strict \
 318        -Wproperty_name_chars_strict \
 319        -Winterrupt_provider
 320endif
 321
 322DTC_FLAGS += $(DTC_FLAGS_$(basetarget))
 323
 324# Set -@ if the target is a base DTB that overlay is applied onto
 325DTC_FLAGS += $(if $(filter $(patsubst $(obj)/%,%,$@), $(base-dtb-y)), -@)
 326
 327# Generate an assembly file to wrap the output of the device tree compiler
 328quiet_cmd_dt_S_dtb= DTB     $@
 329cmd_dt_S_dtb=                                           \
 330{                                                       \
 331        echo '\#include <asm-generic/vmlinux.lds.h>';   \
 332        echo '.section .dtb.init.rodata,"a"';           \
 333        echo '.balign STRUCT_ALIGNMENT';                \
 334        echo '.global __dtb_$(subst -,_,$(*F))_begin';  \
 335        echo '__dtb_$(subst -,_,$(*F))_begin:';         \
 336        echo '.incbin "$<" ';                           \
 337        echo '__dtb_$(subst -,_,$(*F))_end:';           \
 338        echo '.global __dtb_$(subst -,_,$(*F))_end';    \
 339        echo '.balign STRUCT_ALIGNMENT';                \
 340} > $@
 341
 342$(obj)/%.dtb.S: $(obj)/%.dtb FORCE
 343        $(call if_changed,dt_S_dtb)
 344
 345quiet_cmd_dtc = DTC     $@
 346cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \
 347        $(DTC) -o $@ -b 0 \
 348                $(addprefix -i,$(dir $<) $(DTC_INCLUDE)) $(DTC_FLAGS) \
 349                -d $(depfile).dtc.tmp $(dtc-tmp) ; \
 350        cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile)
 351
 352$(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
 353        $(call if_changed_dep,dtc)
 354
 355$(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
 356        $(call if_changed_dep,dtc)
 357
 358quiet_cmd_fdtoverlay = DTOVL   $@
 359      cmd_fdtoverlay = $(objtree)/scripts/dtc/fdtoverlay -o $@ -i $(real-prereqs)
 360
 361$(multi-dtb-y): FORCE
 362        $(call if_changed,fdtoverlay)
 363$(call multi_depend, $(multi-dtb-y), .dtb, -dtbs)
 364
 365DT_CHECKER ?= dt-validate
 366DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),,-m)
 367DT_BINDING_DIR := Documentation/devicetree/bindings
 368# DT_TMP_SCHEMA may be overridden from Documentation/devicetree/bindings/Makefile
 369DT_TMP_SCHEMA ?= $(objtree)/$(DT_BINDING_DIR)/processed-schema.json
 370
 371quiet_cmd_dtb_check =   CHECK   $@
 372      cmd_dtb_check =   $(DT_CHECKER) $(DT_CHECKER_FLAGS) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@
 373
 374define rule_dtc
 375        $(call cmd_and_fixdep,dtc)
 376        $(call cmd,dtb_check)
 377endef
 378
 379$(obj)/%.dt.yaml: $(src)/%.dts $(DTC) $(DT_TMP_SCHEMA) FORCE
 380        $(call if_changed_rule,dtc)
 381
 382dtc-tmp = $(subst $(comma),_,$(dot-target).dts.tmp)
 383
 384# Bzip2
 385# ---------------------------------------------------------------------------
 386
 387# Bzip2 and LZMA do not include size in file... so we have to fake that;
 388# append the size as a 32-bit littleendian number as gzip does.
 389size_append = printf $(shell                                            \
 390dec_size=0;                                                             \
 391for F in $(real-prereqs); do                                    \
 392        fsize=$$($(CONFIG_SHELL) $(srctree)/scripts/file-size.sh $$F);  \
 393        dec_size=$$(expr $$dec_size + $$fsize);                         \
 394done;                                                                   \
 395printf "%08x\n" $$dec_size |                                            \
 396        sed 's/\(..\)/\1 /g' | {                                        \
 397                read ch0 ch1 ch2 ch3;                                   \
 398                for ch in $$ch3 $$ch2 $$ch1 $$ch0; do                   \
 399                        printf '%s%03o' '\\' $$((0x$$ch));              \
 400                done;                                                   \
 401        }                                                               \
 402)
 403
 404quiet_cmd_bzip2 = BZIP2   $@
 405      cmd_bzip2 = { cat $(real-prereqs) | $(KBZIP2) -9; $(size_append); } > $@
 406
 407# Lzma
 408# ---------------------------------------------------------------------------
 409
 410quiet_cmd_lzma = LZMA    $@
 411      cmd_lzma = { cat $(real-prereqs) | $(LZMA) -9; $(size_append); } > $@
 412
 413quiet_cmd_lzo = LZO     $@
 414      cmd_lzo = { cat $(real-prereqs) | $(KLZOP) -9; $(size_append); } > $@
 415
 416quiet_cmd_lz4 = LZ4     $@
 417      cmd_lz4 = { cat $(real-prereqs) | $(LZ4) -l -c1 stdin stdout; \
 418                  $(size_append); } > $@
 419
 420# U-Boot mkimage
 421# ---------------------------------------------------------------------------
 422
 423MKIMAGE := $(srctree)/scripts/mkuboot.sh
 424
 425# SRCARCH just happens to match slightly more than ARCH (on sparc), so reduces
 426# the number of overrides in arch makefiles
 427UIMAGE_ARCH ?= $(SRCARCH)
 428UIMAGE_COMPRESSION ?= $(if $(2),$(2),none)
 429UIMAGE_OPTS-y ?=
 430UIMAGE_TYPE ?= kernel
 431UIMAGE_LOADADDR ?= arch_must_set_this
 432UIMAGE_ENTRYADDR ?= $(UIMAGE_LOADADDR)
 433UIMAGE_NAME ?= 'Linux-$(KERNELRELEASE)'
 434
 435quiet_cmd_uimage = UIMAGE  $@
 436      cmd_uimage = $(BASH) $(MKIMAGE) -A $(UIMAGE_ARCH) -O linux \
 437                        -C $(UIMAGE_COMPRESSION) $(UIMAGE_OPTS-y) \
 438                        -T $(UIMAGE_TYPE) \
 439                        -a $(UIMAGE_LOADADDR) -e $(UIMAGE_ENTRYADDR) \
 440                        -n $(UIMAGE_NAME) -d $< $@
 441
 442# XZ
 443# ---------------------------------------------------------------------------
 444# Use xzkern to compress the kernel image and xzmisc to compress other things.
 445#
 446# xzkern uses a big LZMA2 dictionary since it doesn't increase memory usage
 447# of the kernel decompressor. A BCJ filter is used if it is available for
 448# the target architecture. xzkern also appends uncompressed size of the data
 449# using size_append. The .xz format has the size information available at
 450# the end of the file too, but it's in more complex format and it's good to
 451# avoid changing the part of the boot code that reads the uncompressed size.
 452# Note that the bytes added by size_append will make the xz tool think that
 453# the file is corrupt. This is expected.
 454#
 455# xzmisc doesn't use size_append, so it can be used to create normal .xz
 456# files. xzmisc uses smaller LZMA2 dictionary than xzkern, because a very
 457# big dictionary would increase the memory usage too much in the multi-call
 458# decompression mode. A BCJ filter isn't used either.
 459quiet_cmd_xzkern = XZKERN  $@
 460      cmd_xzkern = { cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh; \
 461                     $(size_append); } > $@
 462
 463quiet_cmd_xzmisc = XZMISC  $@
 464      cmd_xzmisc = cat $(real-prereqs) | $(XZ) --check=crc32 --lzma2=dict=1MiB > $@
 465
 466# ZSTD
 467# ---------------------------------------------------------------------------
 468# Appends the uncompressed size of the data using size_append. The .zst
 469# format has the size information available at the beginning of the file too,
 470# but it's in a more complex format and it's good to avoid changing the part
 471# of the boot code that reads the uncompressed size.
 472#
 473# Note that the bytes added by size_append will make the zstd tool think that
 474# the file is corrupt. This is expected.
 475#
 476# zstd uses a maximum window size of 8 MB. zstd22 uses a maximum window size of
 477# 128 MB. zstd22 is used for kernel compression because it is decompressed in a
 478# single pass, so zstd doesn't need to allocate a window buffer. When streaming
 479# decompression is used, like initramfs decompression, zstd22 should likely not
 480# be used because it would require zstd to allocate a 128 MB buffer.
 481
 482quiet_cmd_zstd = ZSTD    $@
 483      cmd_zstd = { cat $(real-prereqs) | $(ZSTD) -19; $(size_append); } > $@
 484
 485quiet_cmd_zstd22 = ZSTD22  $@
 486      cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@
 487
 488# ASM offsets
 489# ---------------------------------------------------------------------------
 490
 491# Default sed regexp - multiline due to syntax constraints
 492#
 493# Use [:space:] because LLVM's integrated assembler inserts <tab> around
 494# the .ascii directive whereas GCC keeps the <space> as-is.
 495define sed-offsets
 496        's:^[[:space:]]*\.ascii[[:space:]]*"\(.*\)".*:\1:; \
 497        /^->/{s:->#\(.*\):/* \1 */:; \
 498        s:^->\([^ ]*\) [\$$#]*\([^ ]*\) \(.*\):#define \1 \2 /* \3 */:; \
 499        s:->::; p;}'
 500endef
 501
 502# Use filechk to avoid rebuilds when a header changes, but the resulting file
 503# does not
 504define filechk_offsets
 505         echo "#ifndef $2"; \
 506         echo "#define $2"; \
 507         echo "/*"; \
 508         echo " * DO NOT MODIFY."; \
 509         echo " *"; \
 510         echo " * This file was generated by Kbuild"; \
 511         echo " */"; \
 512         echo ""; \
 513         sed -ne $(sed-offsets) < $<; \
 514         echo ""; \
 515         echo "#endif"
 516endef
 517