On Tue, Jun 5, 2018 at 3:52 PM, Guenter Roeck linux@roeck-us.net 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.
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?
Arnd