On Tue, 2014-04-29 at 10:38 -0500, Brian W Hart wrote: > > CHECKFLAGS += -m$(CONFIG_WORD_SIZE) -D__powerpc__ > > -D__powerpc$(CONFIG_WORD_SIZE)__ > > > > +ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE > > KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o > > +endif > > + > > > > # No AltiVec or VSX instructions when building kernel > > KBUILD_CFLAGS += $(call cc-option,-mno-altivec) > > I didn't try building a kernel or in-tree modules, but I confirmed > that it allows building of out-of-tree modules when crtsavres.o is > not present (e.g. as for a distro install where the kernel headers > are provided by package, rather than being manually prepared from > the sources). > > Tested-by: Brian W Hart <ha...@linux.vnet.ibm.com>
I still don't like it. What guarantee do we have that gcc will never call into this with other optimisation settings ? It might decide one day that calling out for saving a large pile of registers is still more efficient than unrolling the whole lot, including for speed. Besides that doesn't fix the root problem. We want to be able to build the kernel with CONFIG_CC_OPTIMIZE_FOR_SIZE and still have modules. So a better solution needs to be found. I don't know what that solution is (we might want to look at what other archs are doing maybe ?), could be to include crtsaveres.S in the build of every module (we really don't want to EXPORT_SYMBOL these guys), but that would mean having it installed somewhere with the kernel headers for out-of-tree modules... If necessary, involve lkml, Rusty etc... but this patch is crap. Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
