From 669e06b19de8f844521a55afbdddbbccf26e5322 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 26 Mar 2019 15:11:12 +0900 Subject: kbuild: move RETPOLINE flags below config-targets When you run a "make *config" target, the retpoline compiler flags are evaluated for nothing because the code is located above the 'ifeq ($(config-targets),1)'. Move it a bit below to avoid unneeded computation in the Kconfig stage. Signed-off-by: Masahiro Yamada --- Makefile | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 026fbc450906..ab635a5507eb 100644 --- a/Makefile +++ b/Makefile @@ -519,15 +519,6 @@ KBUILD_AFLAGS += $(CLANG_FLAGS) export CLANG_FLAGS endif -RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register -RETPOLINE_VDSO_CFLAGS_GCC := -mindirect-branch=thunk-inline -mindirect-branch-register -RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk -RETPOLINE_VDSO_CFLAGS_CLANG := -mretpoline -RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG))) -RETPOLINE_VDSO_CFLAGS := $(call cc-option,$(RETPOLINE_VDSO_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_VDSO_CFLAGS_CLANG))) -export RETPOLINE_CFLAGS -export RETPOLINE_VDSO_CFLAGS - # The expansion should be delayed until arch/$(SRCARCH)/Makefile is included. # Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile. # CC_VERSION_TEXT is referenced from Kconfig (so it needs export), @@ -624,6 +615,15 @@ ifdef CONFIG_FUNCTION_TRACER CC_FLAGS_FTRACE := -pg endif +RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register +RETPOLINE_VDSO_CFLAGS_GCC := -mindirect-branch=thunk-inline -mindirect-branch-register +RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk +RETPOLINE_VDSO_CFLAGS_CLANG := -mretpoline +RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG))) +RETPOLINE_VDSO_CFLAGS := $(call cc-option,$(RETPOLINE_VDSO_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_VDSO_CFLAGS_CLANG))) +export RETPOLINE_CFLAGS +export RETPOLINE_VDSO_CFLAGS + # The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default # values of the respective KBUILD_* variables ARCH_CPPFLAGS := -- cgit v1.2.3 From 0209987fc81c8118e9fc99a115a45b273e8acc75 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 26 Mar 2019 15:32:16 +0900 Subject: kbuild: fix warning "overriding recipe for target 'Makefile'" If you do "make Makefile" with GNU Make 3.x, the following warning is displayed: $ make Makefile Makefile:165: warning: overriding recipe for target 'Makefile' Makefile:51: warning: ignoring old recipe for target 'Makefile' make[1]: Nothing to be done for 'Makefile'. make: Nothing to be done for 'Makefile'. Signed-off-by: Masahiro Yamada --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index ab635a5507eb..f30b37569f5d 100644 --- a/Makefile +++ b/Makefile @@ -161,7 +161,7 @@ ifeq ($(need-sub-make),1) PHONY += $(MAKECMDGOALS) sub-make -$(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make +$(filter-out _all sub-make $(lastword $(MAKEFILE_LIST)), $(MAKECMDGOALS)) _all: sub-make @: # Invoke a second make in the output directory, passing relevant variables -- cgit v1.2.3 From 6b1a9a02c72fdb6e1d67949bb01b66e07d88ace9 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 30 Mar 2019 21:04:13 +0900 Subject: kbuild: pass $(MAKECMDGOALS) to sub-make as is Manipulating $(MAKECMDGOALS) for sub-make seems odd to me. [1] 'make O=foo sub-make' is turned into 'make O=foo', which builds the default targets. It would make sense to terminate the build with: *** No rule to make target 'sub-make'. Stop. [2] 'make O=foo defconfig _all' is turned into 'make O=foo defconfig', which changes the behavior. Let's pass $(MAKECMDGOALS) as is. Signed-off-by: Masahiro Yamada --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index f30b37569f5d..16c77f6cc343 100644 --- a/Makefile +++ b/Makefile @@ -168,7 +168,7 @@ $(filter-out _all sub-make $(lastword $(MAKEFILE_LIST)), $(MAKECMDGOALS)) _all: sub-make: $(Q)$(MAKE) \ $(if $(KBUILD_OUTPUT),-C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR)) \ - -f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS)) + -f $(CURDIR)/Makefile $(MAKECMDGOALS) endif # need-sub-make endif # sub_make_done -- cgit v1.2.3 From 25b146c5b8ceecd43c311552d325a4e403c639f2 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 30 Mar 2019 21:04:14 +0900 Subject: kbuild: allow Kbuild to start from any directory Kbuild always runs in the top of the output directory. If Make starts in the source directory with O=, it relocates the working directory to the location specified by O=. Also, users can start build from the output directory by using the Makefile generated by scripts/mkmakefile. With a little more effort, Kbuild will be able to start from any directory path. This commit allows to specify the source directory by using the -f option. For example, you can do: $ cd path/to/output/dir $ make -f path/to/source/dir/Makefile Or, for the equivalent behavior, you can do: $ make O=path/to/output/dir -f path/to/source/dir/Makefile KBUILD_SRC is now deprecated. Signed-off-by: Masahiro Yamada Reviewed-by: Kieran Bingham --- Makefile | 87 +++++++++++++++++++++++++++++++++++++--------------------------- 1 file changed, 50 insertions(+), 37 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 16c77f6cc343..4929c1f41cfa 100644 --- a/Makefile +++ b/Makefile @@ -96,56 +96,65 @@ endif export quiet Q KBUILD_VERBOSE -# kbuild supports saving output files in a separate directory. -# To locate output files in a separate directory two syntaxes are supported. -# In both cases the working directory must be the root of the kernel src. +# Kbuild will save output files in the current working directory. +# This does not need to match to the root of the kernel source tree. +# +# For example, you can do this: +# +# cd /dir/to/store/output/files; make -f /dir/to/kernel/source/Makefile +# +# If you want to save output files in a different location, there are +# two syntaxes to specify it. +# # 1) O= # Use "make O=dir/to/store/output/files/" # # 2) Set KBUILD_OUTPUT -# Set the environment variable KBUILD_OUTPUT to point to the directory -# where the output files shall be placed. -# export KBUILD_OUTPUT=dir/to/store/output/files/ -# make +# Set the environment variable KBUILD_OUTPUT to point to the output directory. +# export KBUILD_OUTPUT=dir/to/store/output/files/; make # # The O= assignment takes precedence over the KBUILD_OUTPUT environment # variable. -# KBUILD_SRC is not intended to be used by the regular user (for now), -# it is set on invocation of make with KBUILD_OUTPUT or O= specified. - -# OK, Make called in directory where kernel src resides -# Do we want to locate output files in a separate directory? +# Do we want to change the working directory? ifeq ("$(origin O)", "command line") KBUILD_OUTPUT := $(O) endif -ifneq ($(words $(subst :, ,$(CURDIR))), 1) - $(error main directory cannot contain spaces nor colons) +ifneq ($(KBUILD_OUTPUT),) +# Make's built-in functions such as $(abspath ...), $(realpath ...) cannot +# expand a shell special character '~'. We use a somewhat tedious way here. +abs_objtree := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) && pwd) +$(if $(abs_objtree),, \ + $(error failed to create output directory "$(KBUILD_OUTPUT)")) + +# $(realpath ...) resolves symlinks +abs_objtree := $(realpath $(abs_objtree)) +else +abs_objtree := $(CURDIR) +endif # ifneq ($(KBUILD_OUTPUT),) + +ifeq ($(abs_objtree),$(CURDIR)) +# Suppress "Entering directory ..." unless we are changing the work directory. +MAKEFLAGS += --no-print-directory +else +need-sub-make := 1 endif -ifneq ($(KBUILD_OUTPUT),) -# check that the output directory actually exists -saved-output := $(KBUILD_OUTPUT) -KBUILD_OUTPUT := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) \ - && pwd) -$(if $(KBUILD_OUTPUT),, \ - $(error failed to create output directory "$(saved-output)")) +abs_srctree := $(realpath $(dir $(lastword $(MAKEFILE_LIST)))) + +ifneq ($(words $(subst :, ,$(abs_srctree))), 1) +$(error source directory cannot contain spaces or colons) +endif +ifneq ($(abs_srctree),$(abs_objtree)) # Look for make include files relative to root of kernel src # # This does not become effective immediately because MAKEFLAGS is re-parsed -# once after the Makefile is read. It is OK since we are going to invoke -# 'sub-make' below. -MAKEFLAGS += --include-dir=$(CURDIR) - +# once after the Makefile is read. We need to invoke sub-make. +MAKEFLAGS += --include-dir=$(abs_srctree) need-sub-make := 1 -else - -# Do not print "Entering directory ..." at all for in-tree build. -MAKEFLAGS += --no-print-directory - -endif # ifneq ($(KBUILD_OUTPUT),) +endif ifneq ($(filter 3.%,$(MAKE_VERSION)),) # 'MAKEFLAGS += -rR' does not immediately become effective for GNU Make 3.x @@ -155,6 +164,7 @@ need-sub-make := 1 $(lastword $(MAKEFILE_LIST)): ; endif +export abs_srctree abs_objtree export sub_make_done := 1 ifeq ($(need-sub-make),1) @@ -166,9 +176,7 @@ $(filter-out _all sub-make $(lastword $(MAKEFILE_LIST)), $(MAKECMDGOALS)) _all: # Invoke a second make in the output directory, passing relevant variables sub-make: - $(Q)$(MAKE) \ - $(if $(KBUILD_OUTPUT),-C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR)) \ - -f $(CURDIR)/Makefile $(MAKECMDGOALS) + $(Q)$(MAKE) -C $(abs_objtree) -f $(abs_srctree)/Makefile $(MAKECMDGOALS) endif # need-sub-make endif # sub_make_done @@ -213,16 +221,21 @@ ifeq ("$(origin M)", "command line") KBUILD_EXTMOD := $(M) endif -ifeq ($(KBUILD_SRC),) +ifeq ($(abs_srctree),$(abs_objtree)) # building in the source tree srctree := . else - ifeq ($(KBUILD_SRC)/,$(dir $(CURDIR))) + ifeq ($(abs_srctree)/,$(dir $(abs_objtree))) # building in a subdirectory of the source tree srctree := .. else - srctree := $(KBUILD_SRC) + srctree := $(abs_srctree) endif + + # TODO: + # KBUILD_SRC is only used to distinguish in-tree/out-of-tree build. + # Replace it with $(srctree) or something. + KBUILD_SRC := $(abs_srctree) endif export KBUILD_CHECKSRC KBUILD_EXTMOD KBUILD_SRC -- cgit v1.2.3 From a9a49c2ad9b9b8ee20668c15ca2b806dbed8ea40 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 30 Mar 2019 21:04:17 +0900 Subject: kbuild: use $(srctree) instead of KBUILD_SRC to check out-of-tree build KBUILD_SRC was conventionally used for some different purposes: [1] To remember the source tree path [2] As a flag to check if sub-make is already done [3] As a flag to check if Kbuild runs out of tree For [1], we do not need to remember it because the top Makefile can compute it by $(realpath $(dir $(lastword $(MAKEFILE_LIST)))) [2] has been replaced with self-commenting 'sub_make_done'. For [3], we can distinguish in-tree/out-of-tree by comparing $(srctree) and '.' This commit converts [3] to prepare for the KBUILD_SRC removal. Signed-off-by: Masahiro Yamada --- Makefile | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 4929c1f41cfa..72fad444f3e8 100644 --- a/Makefile +++ b/Makefile @@ -448,7 +448,7 @@ USERINCLUDE := \ LINUXINCLUDE := \ -I$(srctree)/arch/$(SRCARCH)/include \ -I$(objtree)/arch/$(SRCARCH)/include/generated \ - $(if $(KBUILD_SRC), -I$(srctree)/include) \ + $(if $(filter .,$(srctree)),,-I$(srctree)/include) \ -I$(objtree)/include \ $(USERINCLUDE) @@ -509,7 +509,7 @@ PHONY += outputmakefile # At the same time when output Makefile generated, generate .gitignore to # ignore whole output directory outputmakefile: -ifneq ($(KBUILD_SRC),) +ifneq ($(srctree),.) $(Q)ln -fsn $(srctree) source $(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree) $(Q)test -e .gitignore || \ @@ -1089,7 +1089,7 @@ PHONY += prepare archprepare prepare1 prepare3 # and if so do: # 1) Check that make has not been executed in the kernel src $(srctree) prepare3: include/config/kernel.release -ifneq ($(KBUILD_SRC),) +ifneq ($(srctree),.) @$(kecho) ' Using $(srctree) as source for kernel' $(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \ echo >&2 " $(srctree) is not clean, please run 'make mrproper'"; \ -- cgit v1.2.3 From 24512795df0901f79a670f8285c450ae912c009d Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 7 Apr 2019 19:03:18 +0900 Subject: kbuild: remove unneeded dependency for include/config/kernel.release This is unneeded since commit 43fee2b23895 ("kbuild: do not redirect the first prerequisite for filechk"). Signed-off-by: Masahiro Yamada --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 72fad444f3e8..7294d4051ff2 100644 --- a/Makefile +++ b/Makefile @@ -1067,7 +1067,7 @@ filechk_kernel.release = \ echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))" # Store (new) KERNELRELEASE string in include/config/kernel.release -include/config/kernel.release: $(srctree)/Makefile FORCE +include/config/kernel.release: FORCE $(call filechk,kernel.release) # Additional helpers built in scripts/ -- cgit v1.2.3 From a788b2ed81abeb949325fd50d7527f45203c1b21 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sun, 7 Apr 2019 19:43:51 +0900 Subject: kbuild: check arch/$(SRCARCH)/include/generated before out-of-tree build After cross-compiling the kernel, "make mrproper" should be executed with the proper ARCH= option. Otherwise, stale objects will remain under arch/$(SRCARCH)/. One bad scenario is like this: $ make ARCH=arm defconfig all # cross-compile the kernel for arm $ make mrproper # mrproper for host-arch (i.e. x86) $ make ARCH=arm O=build_dir defconfig all If you miss ARCH= for mrproper and cross-compile the kernel with O= and ARCH= options, Kbuild will happily start to build, but may fail due to stale objects in the srctree. If $(srctree)/arch/$(SRCARCH)/include/generated/ exists, let's stop the out-of-tree build. To detect this, mrproper should clean only arch/$(SRCARCH)/include/generated/. Signed-off-by: Masahiro Yamada --- Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 7294d4051ff2..04bee1c5b400 100644 --- a/Makefile +++ b/Makefile @@ -1091,7 +1091,9 @@ PHONY += prepare archprepare prepare1 prepare3 prepare3: include/config/kernel.release ifneq ($(srctree),.) @$(kecho) ' Using $(srctree) as source for kernel' - $(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \ + $(Q)if [ -f $(srctree)/.config -o \ + -d $(srctree)/include/config -o \ + -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \ echo >&2 " $(srctree) is not clean, please run 'make mrproper'"; \ echo >&2 " in the '$(srctree)' directory.";\ /bin/false; \ @@ -1350,7 +1352,7 @@ CLEAN_DIRS += $(MODVERDIR) include/ksym # Directories & files removed with 'make mrproper' MRPROPER_DIRS += include/config usr/include include/generated \ - arch/*/include/generated .tmp_objdiff + arch/$(SRCARCH)/include/generated .tmp_objdiff MRPROPER_FILES += .config .config.old .version \ Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS \ signing_key.pem signing_key.priv signing_key.x509 \ -- cgit v1.2.3 From d93a18f27e3701a8cdc2228aee1c22451d1292e4 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 27 Apr 2019 12:33:36 +0900 Subject: kbuild: move samples/ to KBUILD_VMLINUX_OBJS Handle samples/ like the other top-level directories to simplify the Makefile. Include include/config/auto.conf earlier to evaluate drivers-$(CONFIG_SAMPLES). Signed-off-by: Masahiro Yamada --- Makefile | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 04bee1c5b400..87ce8bef6e5c 100644 --- a/Makefile +++ b/Makefile @@ -598,20 +598,21 @@ endif export KBUILD_MODULES KBUILD_BUILTIN +ifeq ($(dot-config),1) +include include/config/auto.conf +endif + ifeq ($(KBUILD_EXTMOD),) # Objects we will link into vmlinux / subdirs we need to visit init-y := init/ drivers-y := drivers/ sound/ +drivers-$(CONFIG_SAMPLES) += samples/ net-y := net/ libs-y := lib/ core-y := usr/ virt-y := virt/ endif # KBUILD_EXTMOD -ifeq ($(dot-config),1) -include include/config/auto.conf -endif - # The all: target is the default when no target is given on the # command line. # This allow a user to issue only 'make' to build a kernel including modules @@ -1006,7 +1007,7 @@ export KBUILD_VMLINUX_LIBS := $(libs-y1) export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds export LDFLAGS_vmlinux # used by scripts/package/Makefile -export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Documentation include samples scripts tools) +export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Documentation include scripts tools) vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) @@ -1043,11 +1044,8 @@ vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps) FORCE targets := vmlinux -# Build samples along the rest of the kernel. This needs headers_install. -ifdef CONFIG_SAMPLES -vmlinux-dirs += samples +# Some samples need headers_install. samples: headers_install -endif # The actual objects are generated when descending, # make sure no implicit rule kicks in @@ -1363,7 +1361,7 @@ MRPROPER_FILES += .config .config.old .version \ # clean: rm-dirs := $(CLEAN_DIRS) clean: rm-files := $(CLEAN_FILES) -clean-dirs := $(addprefix _clean_, . $(vmlinux-alldirs) Documentation samples) +clean-dirs := $(addprefix _clean_, . $(vmlinux-alldirs) Documentation) PHONY += $(clean-dirs) clean archclean vmlinuxclean $(clean-dirs): -- cgit v1.2.3 From 1eaca4b982806b7554438a21831622128acebe82 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 27 Apr 2019 12:33:37 +0900 Subject: kbuild: move Documentation to vmlinux-alldirs A minor code cleanup. Signed-off-by: Masahiro Yamada --- Makefile | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 87ce8bef6e5c..85dd977f4232 100644 --- a/Makefile +++ b/Makefile @@ -989,8 +989,9 @@ vmlinux-dirs := $(patsubst %/,%,$(filter %/, $(init-y) $(init-m) \ $(core-y) $(core-m) $(drivers-y) $(drivers-m) \ $(net-y) $(net-m) $(libs-y) $(libs-m) $(virt-y))) -vmlinux-alldirs := $(sort $(vmlinux-dirs) $(patsubst %/,%,$(filter %/, \ - $(init-) $(core-) $(drivers-) $(net-) $(libs-) $(virt-)))) +vmlinux-alldirs := $(sort $(vmlinux-dirs) Documentation \ + $(patsubst %/,%,$(filter %/, $(init-) $(core-) \ + $(drivers-) $(net-) $(libs-) $(virt-)))) init-y := $(patsubst %/, %/built-in.a, $(init-y)) core-y := $(patsubst %/, %/built-in.a, $(core-y)) @@ -1007,7 +1008,7 @@ export KBUILD_VMLINUX_LIBS := $(libs-y1) export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds export LDFLAGS_vmlinux # used by scripts/package/Makefile -export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Documentation include scripts tools) +export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch include scripts tools) vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) @@ -1361,7 +1362,7 @@ MRPROPER_FILES += .config .config.old .version \ # clean: rm-dirs := $(CLEAN_DIRS) clean: rm-files := $(CLEAN_FILES) -clean-dirs := $(addprefix _clean_, . $(vmlinux-alldirs) Documentation) +clean-dirs := $(addprefix _clean_, . $(vmlinux-alldirs)) PHONY += $(clean-dirs) clean archclean vmlinuxclean $(clean-dirs): -- cgit v1.2.3 From 898490c010b5d2e499e03b7e815fc214209ac583 Mon Sep 17 00:00:00 2001 From: Alexey Gladkov Date: Mon, 29 Apr 2019 18:11:14 +0200 Subject: moduleparam: Save information about built-in modules in separate file Problem: When a kernel module is compiled as a separate module, some important information about the kernel module is available via .modinfo section of the module. In contrast, when the kernel module is compiled into the kernel, that information is not available. Information about built-in modules is necessary in the following cases: 1. When it is necessary to find out what additional parameters can be passed to the kernel at boot time. 2. When you need to know which module names and their aliases are in the kernel. This is very useful for creating an initrd image. Proposal: The proposed patch does not remove .modinfo section with module information from the vmlinux at the build time and saves it into a separate file after kernel linking. So, the kernel does not increase in size and no additional information remains in it. Information is stored in the same format as in the separate modules (null-terminated string array). Because the .modinfo section is already exported with a separate modules, we are not creating a new API. It can be easily read in the userspace: $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Co-Developed-by: Gleb Fotengauer-Malinovskiy Signed-off-by: Gleb Fotengauer-Malinovskiy Signed-off-by: Alexey Gladkov Acked-by: Jessica Yu Signed-off-by: Masahiro Yamada --- Makefile | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 85dd977f4232..9a8b3f94633d 100644 --- a/Makefile +++ b/Makefile @@ -1308,6 +1308,7 @@ _modinst_: fi @cp -f $(objtree)/modules.order $(MODLIB)/ @cp -f $(objtree)/modules.builtin $(MODLIB)/ + @cp -f $(objtree)/modules.builtin.modinfo $(MODLIB)/ $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst # This depmod is only for convenience to give the initial @@ -1348,6 +1349,7 @@ endif # CONFIG_MODULES # Directories & files removed with 'make clean' CLEAN_DIRS += $(MODVERDIR) include/ksym +CLEAN_FILES += modules.builtin.modinfo # Directories & files removed with 'make mrproper' MRPROPER_DIRS += include/config usr/include include/generated \ -- cgit v1.2.3