diff options
Diffstat (limited to 'scripts/Makefile.lib')
-rw-r--r-- | scripts/Makefile.lib | 358 |
1 files changed, 131 insertions, 227 deletions
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 3179747cbd2c..1d581ba5df66 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -1,114 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 -# Backward compatibility -asflags-y += $(EXTRA_AFLAGS) -ccflags-y += $(EXTRA_CFLAGS) -cppflags-y += $(EXTRA_CPPFLAGS) -ldflags-y += $(EXTRA_LDFLAGS) - -# 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 - -ifdef need-dtbslist -dtb-y += $(addsuffix /dtbs-list, $(subdir-ym)) -always-y += dtbs-list -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) $(userprogs-always-m) - -# DTB -# If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built -dtb-$(CONFIG_OF_ALL_DTBS) += $(dtb-) - -# Composite DTB (i.e. DTB constructed by overlay) -multi-dtb-y := $(call multi-search, $(dtb-y), .dtb, -dtbs) -# Primitive DTB compiled from *.dts -real-dtb-y := $(call real-search, $(dtb-y), .dtb, -dtbs) -# Base DTB that overlay is applied onto -base-dtb-y := $(filter %.dtb, $(call real-search, $(multi-dtb-y), .dtb, -dtbs)) - -always-y += $(dtb-y) - -# Add subdir path - -ifneq ($(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)) -dtb-y := $(addprefix $(obj)/, $(dtb-y)) -multi-dtb-y := $(addprefix $(obj)/, $(multi-dtb-y)) -real-dtb-y := $(addprefix $(obj)/, $(real-dtb-y)) -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. @@ -154,7 +44,7 @@ _cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(target-stem).lds) # ifeq ($(CONFIG_GCOV_KERNEL),y) _c_flags += $(if $(patsubst n%,, \ - $(GCOV_PROFILE_$(target-stem).o)$(GCOV_PROFILE)$(CONFIG_GCOV_PROFILE_ALL)), \ + $(GCOV_PROFILE_$(target-stem).o)$(GCOV_PROFILE)$(if $(is-kernel-object),$(CONFIG_GCOV_PROFILE_ALL))), \ $(CFLAGS_GCOV)) endif @@ -165,33 +55,39 @@ endif ifeq ($(CONFIG_KASAN),y) ifneq ($(CONFIG_KASAN_HW_TAGS),y) _c_flags += $(if $(patsubst n%,, \ - $(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)y), \ + $(KASAN_SANITIZE_$(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)y), \ + $(KMSAN_SANITIZE_$(target-stem).o)$(KMSAN_SANITIZE)$(is-kernel-object)), \ $(CFLAGS_KMSAN)) _c_flags += $(if $(patsubst n%,, \ - $(KMSAN_ENABLE_CHECKS_$(target-stem).o)$(KMSAN_ENABLE_CHECKS)y), \ + $(KMSAN_ENABLE_CHECKS_$(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)y), \ + $(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_SANITIZE)$(is-kernel-object)), \ $(CFLAGS_UBSAN)) _c_flags += $(if $(patsubst n%,, \ - $(UBSAN_SIGNED_WRAP_$(target-stem).o)$(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_SIGNED_WRAP)$(UBSAN_SANITIZE)y), \ - $(CFLAGS_UBSAN_SIGNED_WRAP)) + $(UBSAN_INTEGER_WRAP_$(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)$(KCOV_INSTRUMENT)$(CONFIG_KCOV_INSTRUMENT_ALL)), \ + $(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(if $(is-kernel-object),$(CONFIG_KCOV_INSTRUMENT_ALL))), \ $(CFLAGS_KCOV)) +_rust_flags += $(if $(patsubst n%,, \ + $(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(if $(is-kernel-object),$(CONFIG_KCOV_INSTRUMENT_ALL))), \ + $(RUSTFLAGS_KCOV)) endif # @@ -200,7 +96,7 @@ endif # ifeq ($(CONFIG_KCSAN),y) _c_flags += $(if $(patsubst n%,, \ - $(KCSAN_SANITIZE_$(target-stem).o)$(KCSAN_SANITIZE)y), \ + $(KCSAN_SANITIZE_$(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. @@ -209,16 +105,38 @@ _c_flags += $(if $(patsubst n%,, \ -D__KCSAN_INSTRUMENT_BARRIERS__) endif -# $(srctree)/$(src) for including checkin headers from generated source files -# $(objtree)/$(obj) for including generated headers from checkin source files -ifeq ($(KBUILD_EXTMOD),) -ifdef building_out_of_srctree -_c_flags += -I $(srctree)/$(src) -I $(objtree)/$(obj) -_a_flags += -I $(srctree)/$(src) -I $(objtree)/$(obj) -_cpp_flags += -I $(srctree)/$(src) -I $(objtree)/$(obj) +# +# 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], ) @@ -234,7 +152,7 @@ modkern_rustflags = \ modkern_aflags = $(if $(part-of-module), \ $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE), \ - $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)) + $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) $(modfile_flags)) c_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \ -include $(srctree)/include/linux/compiler_types.h \ @@ -244,19 +162,13 @@ c_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \ rust_flags = $(_rust_flags) $(modkern_rustflags) @$(objtree)/include/generated/rustc_cfg a_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \ - $(_a_flags) $(modkern_aflags) + $(_a_flags) $(modkern_aflags) $(modname_flags) cpp_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \ $(_cpp_flags) ld_flags = $(KBUILD_LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F)) -DTC_INCLUDE := $(srctree)/scripts/dtc/include-prefixes - -dtc_cpp_flags = -Wp,-MMD,$(depfile).pre.tmp -nostdinc \ - $(addprefix -I,$(DTC_INCLUDE)) \ - -undef -D__DTS__ - ifdef CONFIG_OBJTOOL objtool := $(objtree)/tools/objtool/objtool @@ -277,8 +189,9 @@ objtool-args-$(CONFIG_MITIGATION_SLS) += --sls objtool-args-$(CONFIG_STACK_VALIDATION) += --stackval objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE) += --static-call objtool-args-$(CONFIG_HAVE_UACCESS_VALIDATION) += --uaccess -objtool-args-$(CONFIG_GCOV_KERNEL) += --no-unreachable +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) \ @@ -289,6 +202,8 @@ 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 @@ -300,6 +215,55 @@ $(foreach m, $1, \ $(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, @@ -311,6 +275,11 @@ quiet_cmd_copy = COPY $@ $(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 # =========================================================================== # @@ -346,91 +315,6 @@ cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@ quiet_cmd_gzip = GZIP $@ cmd_gzip = cat $(real-prereqs) | $(KGZIP) -n -f -9 > $@ -# DTC -# --------------------------------------------------------------------------- -DTC ?= $(objtree)/scripts/dtc/dtc -DTC_FLAGS += \ - -Wno-unique_unit_address - -# Disable noisy checks by default -ifeq ($(findstring 1,$(KBUILD_EXTRA_WARN)),) -DTC_FLAGS += -Wno-unit_address_vs_reg \ - -Wno-avoid_unnecessary_addr_size \ - -Wno-alias_paths \ - -Wno-graph_child_address \ - -Wno-simple_bus_reg -else -DTC_FLAGS += \ - -Wunique_unit_address_if_enabled -endif - -ifneq ($(findstring 2,$(KBUILD_EXTRA_WARN)),) -DTC_FLAGS += -Wnode_name_chars_strict \ - -Wproperty_name_chars_strict \ - -Wunique_unit_address -endif - -DTC_FLAGS += $(DTC_FLAGS_$(target-stem)) - -# Set -@ if the target is a base DTB that overlay is applied onto -DTC_FLAGS += $(if $(filter $(patsubst $(obj)/%,%,$@), $(base-dtb-y)), -@) - -# Generate an assembly file to wrap the output of the device tree compiler -quiet_cmd_wrap_S_dtb = WRAP $@ - cmd_wrap_S_dtb = { \ - symbase=__$(patsubst .%,%,$(suffix $<))_$(subst -,_,$(notdir $*)); \ - echo '\#include <asm-generic/vmlinux.lds.h>'; \ - echo '.section .dtb.init.rodata,"a"'; \ - echo '.balign STRUCT_ALIGNMENT'; \ - echo ".global $${symbase}_begin"; \ - echo "$${symbase}_begin:"; \ - echo '.incbin "$<" '; \ - echo ".global $${symbase}_end"; \ - echo "$${symbase}_end:"; \ - echo '.balign STRUCT_ALIGNMENT'; \ - } > $@ - -$(obj)/%.dtb.S: $(obj)/%.dtb FORCE - $(call if_changed,wrap_S_dtb) - -$(obj)/%.dtbo.S: $(obj)/%.dtbo FORCE - $(call if_changed,wrap_S_dtb) - -quiet_cmd_dtc = DTC $@ -cmd_dtc = $(HOSTCC) -E $(dtc_cpp_flags) -x assembler-with-cpp -o $(dtc-tmp) $< ; \ - $(DTC) -o $@ -b 0 \ - $(addprefix -i,$(dir $<) $(DTC_INCLUDE)) $(DTC_FLAGS) \ - -d $(depfile).dtc.tmp $(dtc-tmp) ; \ - cat $(depfile).pre.tmp $(depfile).dtc.tmp > $(depfile) - -quiet_cmd_fdtoverlay = DTOVL $@ - cmd_fdtoverlay = $(objtree)/scripts/dtc/fdtoverlay -o $@ -i $(real-prereqs) - -$(multi-dtb-y): FORCE - $(call if_changed,fdtoverlay) -$(call multi_depend, $(multi-dtb-y), .dtb, -dtbs) - -ifneq ($(CHECK_DTBS)$(CHECK_DT_BINDING),) -DT_CHECKER ?= dt-validate -DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),-l $(DT_SCHEMA_FILES),-m) -DT_BINDING_DIR := Documentation/devicetree/bindings -DT_TMP_SCHEMA := $(objtree)/$(DT_BINDING_DIR)/processed-schema.json - -quiet_cmd_dtb = DTC_CHK $@ - cmd_dtb = $(cmd_dtc) ; $(DT_CHECKER) $(DT_CHECKER_FLAGS) -u $(srctree)/$(DT_BINDING_DIR) -p $(DT_TMP_SCHEMA) $@ || true -else -quiet_cmd_dtb = $(quiet_cmd_dtc) - cmd_dtb = $(cmd_dtc) -endif - -$(obj)/%.dtb: $(src)/%.dts $(DTC) $(DT_TMP_SCHEMA) FORCE - $(call if_changed_dep,dtb) - -$(obj)/%.dtbo: $(src)/%.dtso $(DTC) FORCE - $(call if_changed_dep,dtc) - -dtc-tmp = $(subst $(comma),_,$(dot-target).dts.tmp) - # Bzip2 # --------------------------------------------------------------------------- @@ -476,10 +360,10 @@ 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 -c1 stdin stdout > $@ + cmd_lz4 = cat $(real-prereqs) | $(LZ4) -l -9 - - > $@ quiet_cmd_lz4_with_size = LZ4 $@ - cmd_lz4_with_size = { cat $(real-prereqs) | $(LZ4) -l -c1 stdin stdout; \ + cmd_lz4_with_size = { cat $(real-prereqs) | $(LZ4) -l -9 - -; \ $(size_append); } > $@ # U-Boot mkimage @@ -504,16 +388,36 @@ quiet_cmd_uimage = UIMAGE $@ -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 to compress the kernel image and xzmisc to compress other things. +# 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 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. +# 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. # |