From: Qian Cai <cai@lca.pw>
To: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: ndesaulniers@google.com,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
natechancellor@gmail.com, Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org
Subject: Re: "arm64: vdso: Substitute gettimeofday() with C implementation" breaks clang build
Date: Tue, 25 Jun 2019 10:28:07 -0400 [thread overview]
Message-ID: <1561472887.5154.72.camel@lca.pw> (raw)
In-Reply-To: <5113362e-1256-6712-6ce8-9599b1806cf1@arm.com>
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.
>
> 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
> > > > >
> > >
> > >
>
>
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next prev parent reply other threads:[~2019-06-25 14:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 12:16 "arm64: vdso: Substitute gettimeofday() with C implementation" breaks clang build Qian Cai
2019-06-25 12:47 ` Vincenzo Frascino
2019-06-25 12:56 ` Qian Cai
2019-06-25 13:40 ` Vincenzo Frascino
2019-06-25 13:51 ` Qian Cai
2019-06-25 14:11 ` Vincenzo Frascino
2019-06-25 14:28 ` Qian Cai [this message]
2019-06-25 14:30 ` Vincenzo Frascino
2019-06-25 14:54 ` Vincenzo Frascino
2019-06-25 15:16 ` Qian Cai
2019-06-25 16:26 ` Nick Desaulniers
2019-06-25 17:00 ` Vincenzo Frascino
2019-06-25 17:31 ` Qian Cai
2019-06-25 17:33 ` Vincenzo Frascino
2019-06-26 9:38 ` Will Deacon
2019-06-26 9:45 ` Vincenzo Frascino
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