On Mon, May 28, 2018 at 05:31:01PM +0200, Arnd Bergmann wrote: > When build testing across architectures, I run into a build error on > all targets other than X86: > > gcc-8.1.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-objdump: net/bpfilter/bpfilter_umh: File format not recognized > gcc-8.1.0-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-objcopy:net/bpfilter/bpfilter_umh.o: Invalid bfd target > > The problem is that 'hostprogs' get built with 'gcc' rather than > '$(CROSS_COMPILE)gcc', and my default gcc (as most people's) targets x86. > > To work around it, adding an X86 dependency gets randconfigs building > again on my box. > > Clearly, this is not a good solution, since it should actually work fine > when building native kernels on other architectures but that is now > disabled, while cross building an x86 kernel on another host is still > broken after my patch. > > What we probably want here is to try out if the compiler is able to build > executables for the target architecture and not build the helper otherwise, > at least when compile-testing. No idea how to do that though. > > Link: http://www.kernel.org/pub/tools/crosstool/ > Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> > Cc: linux-kbuild@xxxxxxxxxxxxxxx > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > net/bpfilter/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig > index 60725c5f79db..61cc4fcbb4d0 100644 > --- a/net/bpfilter/Kconfig > +++ b/net/bpfilter/Kconfig > @@ -9,6 +9,7 @@ menuconfig BPFILTER > if BPFILTER > config BPFILTER_UMH > tristate "bpfilter kernel module with user mode helper" > + depends on X86 # actually depends on native builds depends on X86 will break it on arm. I think the better short term fix would be to test that HOSTCC == CC It doesn't have to be the same compiler. HOSTCC's arch == kernel ARCH Not sure how to hack makefile to do that. Long term we need to get rid of HOSTCC dependency. -- 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
