lkml.org 
[lkml]   [2019]   [Jun]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: "arm64: vdso: Substitute gettimeofday() with C implementation" breaks clang build
    From
    Date
    Hi Qian,

    On 25/06/2019 15:28, Qian Cai wrote:
    > On Tue, 2019-06-25 at 15:11 +0100, Vincenzo Frascino wrote:
    >> 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?
    >
    > Looks like the "tiny" was added since clang 8.0.
    >
    > https://reviews.llvm.org/D49674
    >
    > but clang 7.0 is still use in many distros by default, so maybe this commit can
    > be fixed by adding a conditional check to use "small" if clang version < 8.0.
    >

    It is what I thought that's why I asked to cross-check. I did not want to remove
    tiny.

    Thanks for your support, I will post a patch adding your tag as reported-by if
    you are ok with that.

    >>
    >> 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
    >>>>>>
    >>>>>> ...
    >>>>>>
    >>>>>>   LDS     arch/arm64/kernel/vdso/vdso.lds
    >>>>>>   AS      arch/arm64/kernel/vdso/note.o
    >>>>>>   AS      arch/arm64/kernel/vdso/sigreturn.o
    >>>>>>   CC      arch/arm64/kernel/vdso/vgettimeofday.o
    >>>>>>   LD      arch/arm64/kernel/vdso/vdso.so.dbg
    >>>>>>   VDSOCHK arch/arm64/kernel/vdso/vdso.so.dbg
    >>>>>>   VDSOSYM include/generated/vdso-offsets.h
    >>>>>>
    >>>>>> ...
    >>>>>>
    >>>>>>   LD      vmlinux.o
    >>>>>>   MODPOST vmlinux.o
    >>>>>>   MODINFO modules.builtin.modinfo
    >>>>>>   KSYM    .tmp_kallsyms1.o
    >>>>>>   KSYM    .tmp_kallsyms2.o
    >>>>>>   LD      vmlinux
    >>>>>>   SORTEX  vmlinux
    >>>>>>   SYSMAP  System.map
    >>>>>>   Building modules, stage 2.
    >>>>>>   OBJCOPY arch/arm64/boot/Image
    >>>>>>   MODPOST 483 modules
    >>>>>>
    >>>>
    >>>>
    >>
    >>

    --
    Regards,
    Vincenzo

    \
     
     \ /
      Last update: 2019-06-25 16:31    [W:3.093 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site