This Linux kernel change "parisc: disable -mlong-calls compiler option for kernel modules" is included in the Linux 3.9 release. This change is authored by Helge Deller <deller [at] gmx.de> on Tue Apr 23 21:29:03 2013 +0200. The commit for this change in Linux stable tree is cf71130 (patch).
parisc: disable -mlong-calls compiler option for kernel modules CONFIG_MLONGCALLS was introduced in commit ec758f98328da3eb933a25dc7a2eed01ef44d849 to overcome linker issues when linking huge linux kernels, e.g. with many modules linked in. But in the kernel module loader there is no support yet for the new relocation types, which is why modules built with -mlong-calls can't be loaded. Furthermore, for modules long calls are not really necessary, since we already use stub sections which resolve long distance calls. So, let's just disable this compiler option when compiling kernel modules. Signed-off-by: Helge Deller <[email protected]>
There are 6 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.
arch/parisc/Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile index 01d95e2..113e282 100644 --- a/arch/parisc/Makefile +++ b/arch/parisc/Makefile @@ -65,8 +65,10 @@ ifndef CONFIG_FUNCTION_TRACER endif # Use long jumps instead of long branches (needed if your linker fails to -# link a too big vmlinux executable) -cflags-$(CONFIG_MLONGCALLS) += -mlong-calls +# link a too big vmlinux executable). Not enabled for building modules. +ifdef CONFIG_MLONGCALLS +KBUILD_CFLAGS_KERNEL += -mlong-calls +endif # select which processor to optimise for cflags-$(CONFIG_PA7100) += -march=1.1 -mschedule=7100