kbuild: add option for stripping modules while installing them

Add option for stripping modules while installing them.

This function adds support for stripping modules while they are being
installed.  CONFIG_DEBUG_KERNEL (which will probably become more
popular as developers use kdump) causes the size of the installed
modules to grow by a factor of 9 or so.

Some kernel package systems solve this problem by stripping the debug
information from /lib/modules after running "make modules_install",
but that may not work for people who are installing directly into
/lib/modules --- root partitions that were sized to handle 16 megs
worth of modules may not be quite so happy with 145 megs of modules,
so the "make modules_install" never succeeds.

This patch allows such users to request modules_install to strip the
modules as they are installed.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 1b2fd97f50..d810d6cb4d 100644
--- a/Makefile
+++ b/Makefile
@@ -512,6 +512,23 @@ export	INSTALL_PATH ?= /boot
 MODLIB  = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
 export MODLIB
 
+#
+#  INSTALL_MOD_STRIP, if defined, will cause modules to be
+#  stripped after they are installed.  If INSTALL_MOD_STRIP is '1', then
+#  the default option --strip-debug will be used.  Otherwise,
+#  INSTALL_MOD_STRIP will used as the options to the strip command.
+
+ifdef INSTALL_MOD_STRIP
+ifeq ($(INSTALL_MOD_STRIP),1)
+mod_strip_cmd = $STRIP) --strip-debug
+else
+mod_strip_cmd = $(STRIP) $(INSTALL_MOD_STRIP)
+endif # INSTALL_MOD_STRIP=1
+else
+mod_strip_cmd = true
+endif # INSTALL_MOD_STRIP
+export mod_strip_cmd
+
 
 ifeq ($(KBUILD_EXTMOD),)
 core-y          += kernel/ mm/ fs/ ipc/ security/ crypto/ block/