On Tue, Jun 05, 2018 at 04:31:00PM +0200, Arnd Bergmann wrote: > On Tue, Jun 5, 2018 at 3:52 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > > Hi Arnd, > > > > when using the ppc64 compiler from kernel.org, I see the following problems > > when trying to compile ppc:allnoconfig in v4.14.y or v4.16.y. > > > > gcc 7.3.0: Compilation of kernel.cpu.o hangs > > > > The problem goes away if I apply the following two patches (tested with > > 4.16.y) > > > > 17a2f1ced028 cpu/hotplug: Merge cpuhp_bp_states and cpuhp_ap_states > > fcb3029a8d89 cpu/hotplug: Fix unused function warning > > This is probably the same as > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84038 > > I thought I had included the fix in my builds. > Guess not. > > gcc 8.1.0: Compilation of kernel/cpu.o results in the following error > > > > powerpc64-linux-gcc: error: unrecognized command line option '-mno-spe'; did > > you mean '-fno-see'? > > powerpc64-linux-gcc: error: unrecognized command line option '-mspe=no'; did > > you mean '-misel=no'? > > > > This problem is also seen with mainline. > > I've seen it, but couldn't figure out what the right fix is. I ended > up commenting > out those two lines in my private builds: > > --- a/arch/powerpc/Makefile > +++ b/arch/powerpc/Makefile > @@ -215,8 +215,8 @@ KBUILD_CFLAGS += $(call cc-option,-mno-vsx) > > # No SPE instruction when building kernel > # (We use all available options to help semi-broken compilers) > -KBUILD_CFLAGS += $(call cc-option,-mno-spe) > -KBUILD_CFLAGS += $(call cc-option,-mspe=no) > +#KBUILD_CFLAGS += $(call cc-option,-mno-spe) > +#KBUILD_CFLAGS += $(call cc-option,-mspe=no) > > # Enable unit-at-a-time mode when possible. It shrinks the > # kernel considerably. > > I think there were some changes in how cc-option gets evaluated, maybe > those rely on something else to be enabled or disabled first? > I think it may have cached the flags from the other compiler version. "make mrproper" prior to "make defconfig" took care of the issue. However, that doesn't really help - I get lots of error: 'sys_spu_create' alias between functions of incompatible types error: 'strncpy' output truncated before terminating nul if I try to use gcc 8.1.0. Oh well. I'll try gcc 6.4.0 next. Thanks, Guenter
