On Fri, Jan 12, 2018 at 3:11 PM, kbuild test robot <fengguang.wu@xxxxxxxxx> wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master > head: b40fa82cd6138350f723aa47b37e3e3e80906b40 > commit: 148b974deea927f5dbb6c468af2707b488bfa2de [130/134] crypto: aes-generic - build with -Os on gcc-7+ > config: powerpc-linkstation_defconfig (attached as .config) > compiler: powerpc-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0 > reproduce: > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > git checkout 148b974deea927f5dbb6c468af2707b488bfa2de > # save the attached .config to linux build tree > make.cross ARCH=powerpc > > All errors (new ones prefixed by >>): > > crypto/aes_generic.o: In function `crypto_aes_set_key': >>> aes_generic.c:(.text+0x4e0): undefined reference to `_restgpr_31_x' adding linuxpcc-dev to Cc, maybe someone knows a way out of this. It appears related to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43810 but I don't know what _restgpr_31_x actually does, why it's not provided by the kernel or why the aes_generic implementation needs this on powerpc when built with 'gcc -Os'. FWIW, the -Os change was needed to work around a possible kernel stack overflow that can happen with gcc-7.2, see https://patchwork.kernel.org/patch/10143607/ and https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83356 Arnd
