From: tony@atomide•com (Tony Lindgren)
To: linux-arm-kernel@lists•infradead.org
Subject: ARM errata 430973 on multi platform kernels
Date: Mon, 4 May 2015 07:24:13 -0700 [thread overview]
Message-ID: <20150504142413.GE24469@atomide.com> (raw)
In-Reply-To: <20150429144011.GB24469@atomide.com>
* Tony Lindgren <tony@atomide•com> [150429 07:42]:
> * Russell King - ARM Linux <linux@arm•linux.org.uk> [150428 11:14]:
> > On Thu, Apr 23, 2015 at 07:17:28AM -0700, Tony Lindgren wrote:
> > > * Russell King - ARM Linux <linux@arm•linux.org.uk> [150423 03:26]:
> > > > However, I don't think anyone is willing to say that they have a
> > > > solution to this problem - obviously, you can't build OMAP as a
> > > > non-multiplatform kernel anymore, so in effect you can never have
> > > > the kernel enable this errata. And you can't detect whether you're
> > > > running in secure mode or not.
> > > >
> > > > We could do the "only write the bit if it was originally clear" but
> > > > we still have the problem that doing so may cause other people
> > > > regressions.
> > >
> > > How about we keep the bit writing part !multiplatform conditional
> > > (or even remove it) but always do the flush for ca-8?
> > >
> > > Then we could also do a warning for a misconfigured ca-8 later on.
> >
> > Yes, we could do this - we'll have to rely on the boot loader doing
> > the right thing and setting this bit appropriately. For those
> > platforms where this doesn't apply, I don't see any solution as (iirc)
> > OMAP now requires MULTIPLATFORM to be enabled.
>
> OK, here's an updated patch. I've kept Sebastian's Tested-by as we know
> the init part is a nop on n900 that he tested with.
I've posted this updated version into Russell's patch system:
http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=8353/1
Regards,
Tony
> 8< ---------------------
> From: Tony Lindgren <tony@atomide•com>
> Date: Mon, 27 Apr 2015 10:18:14 -0700
> Subject: [PATCH] ARM: mm: Fix Cortex-A8 erratum 430973 segfaults for bootloaders and multiarch
>
> Looks like apps can be made to segfault easily on armhf distros
> just by running cpuburn-a8 in the background, then starting apt
> get update unless erratum 430973 workaround is enabled. This happens
> on r3p2 also, which has 430973 fixed in hardware.
>
> Turns out the reason for this is some bootloaders incorrectly
> setting the auxilary register IBE bit, which probably causes us
> to hit erratum 687067 on Cortex-A8 later than r1p2.
>
> If the bootloader incorrectly sets the IBE bit in the auxilary control
> register for Cortex-A8 revisions with 430973 fixed in hardware, we
> need to call flush BTAC/BTB to avoid segfaults probably caused by
> erratum 687067. So let's flush BTAC/BTB unconditionally for Cortex-A8.
> It won't do anything unless the IBE bit is set.
>
> Note that we keep the erratum 430973 Kconfig option still around and
> disabled for multiarch as it may be unsafe to enable for some secure
> SoC. It is known safe to be enabled for n900, but won't do anything
> on n900 as the IBE bit needs to be set with SMC.
>
> Also note that SoCs probably should also add checks and print warnings
> for the misconfigured IBE bit depending on the Cortex-A8 revision
> so the bootloaders can be fixed Cortex-A8 revisions later than
> r1p2 to not set the IBE bit.
>
> Tested-By: Sebastian Reichel <sre@kernel•org>
> Signed-off-by: Tony Lindgren <tony@atomide•com>
>
> --- a/arch/arm/mm/proc-v7-2level.S
> +++ b/arch/arm/mm/proc-v7-2level.S
> @@ -36,14 +36,16 @@
> *
> * It is assumed that:
> * - we are not using split page tables
> + *
> + * Note that we always need to flush BTAC/BTB if IBE is set
> + * even on Cortex-A8 revisions not affected by 430973.
> + * If IBE is not set, the flush BTAC/BTB won't do anything.
> */
> ENTRY(cpu_ca8_switch_mm)
> #ifdef CONFIG_MMU
> mov r2, #0
> -#ifdef CONFIG_ARM_ERRATA_430973
> mcr p15, 0, r2, c7, c5, 6 @ flush BTAC/BTB
> #endif
> -#endif
> ENTRY(cpu_v7_switch_mm)
> #ifdef CONFIG_MMU
> mmid r1, r1 @ get mm->context.id
> --
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next prev parent reply other threads:[~2015-05-04 14:24 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1425236828-28349-1-git-send-email-jarkko.nikula@bitmer.com>
[not found] ` <55197A12.1050009@bitmer.com>
[not found] ` <20150330164237.GJ10805@atomide.com>
[not found] ` <55198BA4.5010207@bitmer.com>
[not found] ` <20150330175051.GK10805@atomide.com>
[not found] ` <20150331123233.GA15103@earth>
[not found] ` <20150401194734.GT10805@atomide.com>
[not found] ` <20150403163553.GA16247@earth>
2015-04-03 18:39 ` ARM errata 430973 on multi platform kernels (was: OMAP3-N900: Add microphone bias voltages) Tony Lindgren
2015-04-03 19:21 ` Robert Nelson
2015-04-05 13:00 ` Sebastian Reichel
2015-04-05 13:26 ` Pali Rohár
2015-04-05 13:45 ` Sebastian Reichel
2015-04-05 13:52 ` Pali Rohár
2015-04-06 17:38 ` Sebastian Reichel
2015-04-03 20:42 ` Pavel Machek
2015-04-03 22:08 ` ARM errata 430973 on multi platform kernels Ivaylo Dimitrov
2015-04-03 22:15 ` Tony Lindgren
2015-04-03 22:47 ` Ivaylo Dimitrov
2015-04-03 22:52 ` Tony Lindgren
2015-04-05 4:13 ` Matthijs van Duin
2015-04-05 7:23 ` Ivaylo Dimitrov
2015-04-05 16:50 ` Matthijs van Duin
2015-04-05 16:52 ` Matthijs van Duin
2015-04-05 21:08 ` Ivaylo Dimitrov
2015-04-05 23:52 ` Matthijs van Duin
2015-04-06 15:19 ` Tony Lindgren
2015-04-06 15:40 ` Tony Lindgren
2015-04-06 17:14 ` Ivaylo Dimitrov
2015-04-06 17:42 ` Tony Lindgren
2015-04-06 18:14 ` Matthijs van Duin
2015-04-07 2:23 ` Tony Lindgren
2015-04-07 3:12 ` Sebastian Reichel
2015-04-07 3:49 ` Matthijs van Duin
2015-04-07 14:48 ` Tony Lindgren
2015-04-09 22:37 ` Grazvydas Ignotas
2015-04-09 22:44 ` Tony Lindgren
2015-04-09 23:44 ` Nishanth Menon
2015-04-10 22:05 ` Grazvydas Ignotas
2015-04-10 23:08 ` Tony Lindgren
2015-04-16 16:53 ` Matthijs van Duin
2015-04-07 13:58 ` Russell King - ARM Linux
2015-04-07 13:57 ` Russell King - ARM Linux
2015-04-07 15:22 ` Tony Lindgren
2015-04-07 15:44 ` Tony Lindgren
2015-04-08 23:08 ` Russell King - ARM Linux
2015-04-08 23:15 ` Tony Lindgren
2015-04-08 23:06 ` Russell King - ARM Linux
2015-04-09 13:48 ` Russell King - ARM Linux
2015-04-09 15:09 ` Tony Lindgren
2015-04-09 15:30 ` Russell King - ARM Linux
2015-04-15 16:31 ` Sebastian Reichel
2015-04-16 16:08 ` Tony Lindgren
2015-04-17 18:41 ` Sebastian Reichel
2015-04-20 23:40 ` Tony Lindgren
2015-04-23 10:25 ` Russell King - ARM Linux
2015-04-23 14:17 ` Tony Lindgren
2015-04-28 18:13 ` Russell King - ARM Linux
2015-04-29 14:40 ` Tony Lindgren
2015-05-04 14:24 ` Tony Lindgren [this message]
2015-04-24 8:54 ` Matthijs van Duin
2015-04-28 18:11 ` Russell King - ARM Linux
2015-05-02 6:51 ` Matthijs van Duin
2015-04-05 13:39 ` Sebastian Reichel
2015-04-06 15:24 ` Tony Lindgren
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