Problems building ppc images in v4.14.y and v4.16.y using gcc 7.3.0 / 8.1.0 from kernel.org
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
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.
With ppc:defconfig, kernel/cpu.o builds fine with both compiler versions.
Have you seen similar problems ? Any idea what to do about it, other than sticking with older compilers ?
Thanks, Guenter
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
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@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.
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
On Tue, Jun 5, 2018 at 6:06 PM, Guenter Roeck linux@roeck-us.net wrote:
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@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.
Guess not.
I probably had it in one build and then forgot about it when I did a rebuild of 7.3 :(
I'm still planning to do a new set of gcc-7.3 binaries (or maybe 7.4 if that gets released soon) and should try to remember doing that.
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.
On the upside, those two errors are just a result of arch/power/*/*.c getting built with -Werror, they are warnings that gcc-8 introduced that we should either shut up or fix.
Arnd
Le 05/06/2018 à 21:47, Arnd Bergmann a écrit :
On Tue, Jun 5, 2018 at 6:06 PM, Guenter Roeck linux@roeck-us.net wrote:
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@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.
Guess not.
I probably had it in one build and then forgot about it when I did a rebuild of 7.3 :(
I'm still planning to do a new set of gcc-7.3 binaries (or maybe 7.4 if that gets released soon) and should try to remember doing that.
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.
On the upside, those two errors are just a result of arch/power/*/*.c getting built with -Werror, they are warnings that gcc-8 introduced that we should either shut up or fix.
They are fixed in next:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?... https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?...
Christophe
Arnd
linux-stable-mirror@lists.linaro.org
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Arnd Bergmann -
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Guenter Roeck