On 1/20/2018 2:44 AM, Herbert Xu wrote: > On Mon, Jan 15, 2018 at 05:07:22PM +0100, Arnd Bergmann wrote: >> My last bugfix added -Os on the command line, which unfortunately caused >> a build regression on powerpc in some configurations. >> >> I've done some more analysis of the original problem and found slightly >> different workaround that avoids this regression and also results in >> better performance on gcc-7.0: -fcode-hoisting is an optimization step >> that got added in gcc-7 and that for all gcc-7 versions causes worse >> performance. >> >> This disables -fcode-hoisting on all compilers that understand the option. >> For gcc-7.1 and 7.2 I found the same performance as my previous patch >> (using -Os), in gcc-7.0 it was even better. On gcc-8 I could see no >> change in performance from this patch. In theory, code hoisting should >> not be able make things better for the AES cipher, so leaving it >> disabled for gcc-8 only serves to simplify the Makefile change. >> >> Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx> >> Link: https://www.mail-archive.com/linux-crypto@xxxxxxxxxxxxxxx/msg30418.html >> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83356 >> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83651 >> Fixes: 148b974deea9 ("crypto: aes-generic - build with -Os on gcc-7+") >> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > > Patch applied. Thanks. > This fix ("commit 6e36719fbe90213fbba9f50093fa2d4d69b0e93c upstream") is needed also in 4.14.y stable tree, since it contains commit 7cae67e31292 ("crypto: aes-generic - build with -Os on gcc-7+") Compilation fails without it: crypto/aes_generic.o: In function `crypto_aes_set_key': crypto/aes_generic.c:1300: undefined reference to `_restgpr_31_x' Thanks, Horia
