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From: Arnd Bergmann <arnd@arndb.de>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>,
	linux- stable <stable@vger.kernel.org>,
	lkft-triage@lists.linaro.org, Sasha Levin <sashal@kernel.org>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Marc Zyngier <maz@kernel.org>
Subject: Re: stable-rc 5.4: arm64 build failed - error: ‘const struct arch_timer_erratum_workaround’ has no member named ‘disable_compat_vdso’
Date: Wed, 15 Jul 2020 08:54:33 +0200	[thread overview]
Message-ID: <CAK8P3a2B6xO-PEOEsseajBvJCvF0d269XHvOzqzdfhyssZ6wrw@mail.gmail.com> (raw)
In-Reply-To: <20200714184013.GA2174489@kroah.com>

On Tue, Jul 14, 2020 at 8:40 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Tue, Jul 14, 2020 at 10:48:14PM +0530, Naresh Kamboju wrote:
> > arm64 build failed on 5.4
> >
> > make -sk KBUILD_BUILD_USER=TuxBuild -C/linux -j16 ARCH=arm64
> > CROSS_COMPILE=aarch64-linux-gnu- HOSTCC=gcc CC="sccache
> > aarch64-linux-gnu-gcc" O=build Image
> > #
> > ../drivers/clocksource/arm_arch_timer.c:484:4: error: ‘const struct
> > arch_timer_erratum_workaround’ has no member named
> > ‘disable_compat_vdso’
> >   484 |   .disable_compat_vdso = true,
> >       |    ^~~~~~~~~~~~~~~~~~~
> > ../drivers/clocksource/arm_arch_timer.c:484:26: warning:
> > initialization of ‘u32 (*)(void)’ {aka ‘unsigned int (*)(void)’} from
> > ‘int’ makes pointer from integer without a cast [-Wint-conversion]
> >   484 |   .disable_compat_vdso = true,
> >       |                          ^~~~
> > ../drivers/clocksource/arm_arch_timer.c:484:26: note: (near
> > initialization for ‘ool_workarounds[5].read_cntp_tval_el0’)
> >
> > Could be this patch,
> > arm64: arch_timer: Disable the compat vdso for cores affected by
> > ARM64_WORKAROUND_1418040
> > commit 4b661d6133c5d3a7c9aca0b4ee5a78c7766eff3f upstream.
> >
> > ARM64_WORKAROUND_1418040 requires that AArch32 EL0 accesses to
> > the virtual counter register are trapped and emulated by the kernel.
> > This makes the vdso pretty pointless, and in some cases livelock
> > prone.
> >
> > Provide a workaround entry that limits the vdso to 64bit tasks.
> >
> > ref:
> > https://gitlab.com/Linaro/lkft/kernel-runs/-/jobs/638094006
>
> Thanks, I've now dropped this patch.

I think we do want to have it back eventually. It appears that the patch
upstream depends on the two immediately before it:

4b661d6133c5 arm64: arch_timer: Disable the compat vdso for cores
affected by ARM64_WORKAROUND_1418040
c1fbec4ac0d7 arm64: arch_timer: Allow an workaround descriptor to
disable compat vdso
97884ca8c292 arm64: Introduce a way to disable the 32bit vdso

AFAICT, the second one was missing, causing the build failure.
Do you know if that one needed a manual backport, or could you
try applying all three in sequence again?

      Arnd

  reply	other threads:[~2020-07-15  6:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14 17:18 stable-rc 5.4: arm64 build failed - error: ‘const struct arch_timer_erratum_workaround’ has no member named ‘disable_compat_vdso’ Naresh Kamboju
2020-07-14 18:40 ` Greg Kroah-Hartman
2020-07-15  6:54   ` Arnd Bergmann [this message]
2020-07-15  9:27     ` Greg Kroah-Hartman
2020-07-15 10:16       ` Marc Zyngier

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