If CONFIG_TRIM_UNUSED_KSYMS is enabled and we build the kernel with a specific target, eg. "make vmlinux" rather than simply "make", we need to build module source in order to generate the .mod files in $MODVERDIR (.tmp_versions/). Without doing so we: 1) Trigger an error from sed due to the missing files during the build of vmlinux: CHK include/generated/autoksyms.h sed: can't read .tmp_versions/*.mod: No such file or directory 2) Discard all symbol exports since we kept no record of which ones may be used: $ nm vmlinux | grep ksymtab 8069c9b8 R __start___ksymtab 8069c9b8 R __start___ksymtab_gpl 8069c9b8 R __start___ksymtab_gpl_future 8069c9b8 R __start___ksymtab_unused 8069c9b8 R __start___ksymtab_unused_gpl 8069c9b8 R __stop___ksymtab 8069c9b8 R __stop___ksymtab_gpl 8069c9b8 R __stop___ksymtab_gpl_future 8069c9b8 R __stop___ksymtab_unused 8069c9b8 R __stop___ksymtab_unused_gpl 3) Fail to build modules if we then run "make modules", since the modules reference symbols which we have discarded: ERROR: "pnfs_unregister_layoutdriver" [fs/nfs/flexfilelayout/nfs_layout_flexfiles.ko] undefined! ERROR: "nfs4_schedule_session_recovery" [fs/nfs/flexfilelayout/nfs_layout_flexfiles.ko] undefined! ... Fix this by ensuring that we build modules as part of the main kernel build by setting KBUILD_MODULES to 1 when CONFIG_TRIM_UNUSED_KSYMS is enabled, regardless of what was specified as the make target. Doing this involves exporting KBUILD_MODULES from the main Makefile after having read the configuration, later than it was previously exported. Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx> Cc: Michal Marek <mmarek@xxxxxxxx> Cc: linux-kbuild@xxxxxxxxxxxxxxx --- Makefile | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/Makefile b/Makefile index f97f786..ce1b44a 100644 --- a/Makefile +++ b/Makefile @@ -336,7 +336,7 @@ ifeq ($(MAKECMDGOALS),) KBUILD_MODULES := 1 endif -export KBUILD_MODULES KBUILD_BUILTIN +export KBUILD_BUILTIN export KBUILD_CHECKSRC KBUILD_SRC KBUILD_EXTMOD # We need some generic definitions (do not try to remake the file). @@ -606,6 +606,16 @@ else include/config/auto.conf: ; endif # $(dot-config) +# If we're using CONFIG_TRIM_UNUSED_KSYMS then we need to compile +# modules in order to generate the .mod files in $MODVERDIR so that +# we know which symbols to export. + +ifdef CONFIG_TRIM_UNUSED_KSYMS + KBUILD_MODULES := 1 +endif + +export KBUILD_MODULES + # 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 -- 2.10.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
