Re: "arm64: vdso: Substitute gettimeofday() with C implementation" breaks clang build

[Vincenzo Frascino]

Hi Qian,

On 25/06/2019 14:51, Qian Cai wrote:
> On Tue, 2019-06-25 at 14:40 +0100, Vincenzo Frascino wrote:
>> On 25/06/2019 13:56, Qian Cai wrote:
>>> On Tue, 2019-06-25 at 13:47 +0100, Vincenzo Frascino wrote:
>>>> Hi Qian,
>>>>
>>>> On 25/06/2019 13:16, Qian Cai wrote:
>>>>> The linux-next commit "arm64: vdso: Substitute gettimeofday() with C
>>>>> implementation" [1] breaks clang build.
>>>>>
>>>>> error: invalid value 'tiny' in '-mcode-model tiny'
>>>>> make[1]: *** [scripts/Makefile.build:279:
>>>>> arch/arm64/kernel/vdso/vgettimeofday.o] Error 1
>>>>> make[1]: *** Waiting for unfinished jobs....
>>>>> make: *** [arch/arm64/Makefile:180: vdso_prepare] Error 2
>>>>>
>>>>> [1] https://patchwork.kernel.org/patch/11009663/
>>>>>
>>>>
>>>> I am not sure what does exactly break from your report. Could you please
>>>> provide
>>>> more details?
>>>
>>> Here is the config to reproduce.
>>>
>>> https://raw.githubusercontent.com/cailca/linux-mm/master/arm64.config
>>>
>>> # make CC=clang -j $(nr_cpus)
>>>
>>> I can get it working again by removing "-mcmodel=tiny" in
>>> arch/arm64/kernel/vdso/Makefile
>>>
>>
>> With your defconfig I can't still reproduce the problem. Which version of
>> clang
>> are you using?
> 
> Compiler: clang version 7.0.1 (tags/RELEASE_701/final)
> 

I am using clang 8.0.0. Could you please try with it and see if the issue goes away?

Thanks,
Vincenzo

>>
>>>>
>>>> On my env:
>>>>
>>>> $ make mrproper && make defconfig && make CC=clang HOSTCC=clang -j$(nproc)
>>>>
>>>> ...
>>>>
>>>> arch/arm64/Makefile:56: CROSS_COMPILE_COMPAT is clang, the compat vDSO
>>>> will
>>>> not
>>>> be built
>>>>
>>>> ...
>>>>
>>>> Â LDSÂÂÂÂÂarch/arm64/kernel/vdso/vdso.lds
>>>> Â ASÂÂÂÂÂÂarch/arm64/kernel/vdso/note.o
>>>> Â ASÂÂÂÂÂÂarch/arm64/kernel/vdso/sigreturn.o
>>>> Â CCÂÂÂÂÂÂarch/arm64/kernel/vdso/vgettimeofday.o
>>>> Â LDÂÂÂÂÂÂarch/arm64/kernel/vdso/vdso.so.dbg
>>>> Â VDSOCHK arch/arm64/kernel/vdso/vdso.so.dbg
>>>> Â VDSOSYM include/generated/vdso-offsets.h
>>>>
>>>> ...
>>>>
>>>> Â LDÂÂÂÂÂÂvmlinux.o
>>>> Â MODPOST vmlinux.o
>>>> Â MODINFO modules.builtin.modinfo
>>>> Â KSYMÂÂÂÂ.tmp_kallsyms1.o
>>>> Â KSYMÂÂÂÂ.tmp_kallsyms2.o
>>>> Â LDÂÂÂÂÂÂvmlinux
>>>> Â SORTEXÂÂvmlinux
>>>> Â SYSMAPÂÂSystem.map
>>>> Â Building modules, stage 2.
>>>> Â OBJCOPY arch/arm64/boot/Image
>>>> Â MODPOST 483 modules
>>>>
>>
>>

-- 
Regards,
Vincenzo