From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexey Brodkin Date: Mon, 19 Sep 2016 17:12:05 +0300 Subject: [Buildroot] [PATCH v2] linux: Allow kernel strip modules itself Message-ID: <1474294325-6340-1-git-send-email-abrodkin@synopsys.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net We used to do a special handling of Linux kernel modules when stripping target binaries because there's some special precious data in modules that we must keep for them to properly operate. This is for example true for stack unwinding data etc. It turned out there're cases when our existing "strip --strip-unneeded" doesn't work well. For example this removes .debug_frame section used by Linux on ARC for stack unwinding, refer to [1] and [2] for more details. Now Linux kernel may strip modules as a part of "modules_install" target if INSTALL_MOD_STRIP=1 is passed in command line. And so we'll do allowing kernel decide how to strip modules in the best way. Still note as of today Linux kernel strips modules uniformly for all arches with "strip" command, so this commit alone doesn't solve mentioned problem but it opens a possibility to add later a patch to the kernel which will strip modules for ARC differently - and that's our plan for mainline kernel. [1] https://github.com/foss-for-synopsys-dwc-arc-processors/toolchain/issues/86 [2] http://lists.busybox.net/pipermail/buildroot/2016-September/172161.html Signed-off-by: Alexey Brodkin Cc: Vineet Gupta Cc: Peter Korsgaard Cc: Thomas Petazzoni Cc: Daniel Mentz --- Changes v1 -> v2: As suggested by Thomas: * Use existing LINUX_MAKE_FLAGS variable so strip flag gets propagated automatically in all users of LINUX_MAKE_FLAGS such as: - LINUX_INSTALL_TARGET_CMDS - $(2)_KERNEL_MODULES_INSTALL * Minor clean-up Makefile | 3 --- linux/linux.mk | 4 ++++ package/Makefile.in | 3 --- 3 files changed, 4 insertions(+), 6 deletions(-) diff --git a/Makefile b/Makefile index dfef021..0a44fa7 100644 --- a/Makefile +++ b/Makefile @@ -631,9 +631,6 @@ endif rm -rf $(TARGET_DIR)/usr/share/gtk-doc -rmdir $(TARGET_DIR)/usr/share 2>/dev/null $(STRIP_FIND_CMD) | xargs -0 $(STRIPCMD) 2>/dev/null || true - if test -d $(TARGET_DIR)/lib/modules; then \ - find $(TARGET_DIR)/lib/modules -type f -name '*.ko' -print0 | \ - xargs -0 -r $(KSTRIPCMD); fi # See http://sourceware.org/gdb/wiki/FAQ, "GDB does not see any threads # besides the one in which crash occurred; or SIGTRAP kills my program when diff --git a/linux/linux.mk b/linux/linux.mk index 6e41a92..5cbb5e5 100644 --- a/linux/linux.mk +++ b/linux/linux.mk @@ -384,6 +384,10 @@ define LINUX_INSTALL_IMAGES_CMDS $(call LINUX_INSTALL_DTB,$(BINARIES_DIR)) endef +ifeq ($(BR2_STRIP_strip),y) +LINUX_MAKE_FLAGS += INSTALL_MOD_STRIP=1 +endif + define LINUX_INSTALL_TARGET_CMDS $(LINUX_INSTALL_KERNEL_IMAGE_TO_TARGET) # Install modules and remove symbolic links pointing to build diff --git a/package/Makefile.in b/package/Makefile.in index afd5d3a..83c9a89 100644 --- a/package/Makefile.in +++ b/package/Makefile.in @@ -203,16 +203,13 @@ TARGET_OBJDUMP = $(TARGET_CROSS)objdump ifeq ($(BR2_STRIP_strip),y) STRIP_STRIP_DEBUG := --strip-debug -STRIP_STRIP_UNNEEDED := --strip-unneeded STRIP_STRIP_ALL := --strip-all TARGET_STRIP = $(TARGET_CROSS)strip STRIPCMD = $(TARGET_CROSS)strip --remove-section=.comment --remove-section=.note -KSTRIPCMD = $(STRIPCMD) $(STRIP_STRIP_UNNEEDED) endif ifeq ($(BR2_STRIP_none),y) TARGET_STRIP = true STRIPCMD = $(TARGET_STRIP) -KSTRIPCMD = $(TARGET_STRIP) endif INSTALL := $(shell which install || type -p install) FLEX := $(shell which flex || type -p flex) -- 2.7.4