From: tony@atomide•com (Tony Lindgren)
To: linux-arm-kernel@lists•infradead.org
Subject: ARM errata 430973 on multi platform kernels
Date: Tue, 7 Apr 2015 08:22:08 -0700 [thread overview]
Message-ID: <20150407152207.GM18048@atomide.com> (raw)
In-Reply-To: <20150407135713.GL4027@n2100.arm.linux.org.uk>
* Russell King - ARM Linux <linux@arm•linux.org.uk> [150407 06:58]:
> On Mon, Apr 06, 2015 at 10:42:45AM -0700, Tony Lindgren wrote:
> > * Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail•com> [150406 10:15]:
> > > On 6.04.2015 18:40, Tony Lindgren wrote:
> > > >
> > > >Oops sorry, wrong numbers for errata above.. s/458693/430973/, here's
> > > >a better version:
> > > >
> > > >1. For cortex-a8 revisions affected by 430973, we can do a custom
> > > > cpu_v7_switch_mm function that always does flush BTAC/BTB.
> > > >
> > >
> > > Why custom function, if IBE bit is zero, BTB invalidate instruction is a
> > > NOP. Do you think that "mcr p15, 0, r2, c7, c5, 6" executed as a NOP will
> > > put so much overhead, that it deserves a custom function?
> >
> > Hmm but it still seems to do something also on cortex-a8 r3p2 that
> > is supposedly not affected by 430973.. Based on my tests so far, at least
> > armhf running cpuburn-a8 in the background and doing apt-get update
> > segfaults constantly without flush BTAC/BTB. This seems to be the case
> > no matter how the aux ctrl reg bits are set.. This should be reproducable
> > on any pandboard xm BTW.
> >
> > > >2. For HS cortex-a8 processors other than n900 affected by 430973,
> > > > we need to implement functions similar to rx51_secure_update_aux_cr,
> > > > the bootrom on n900 is different from TI HS omaps so the SMC call
> > > > numbering may be different.
> > > >
> > > >3. For later cortex-a8 processors not affected by 430973, we need
> > > > to clear IBE bit to avoid erratum 687067.
> > > >
> > >
> > > Maybe it should be implemented something like:
> > >
> > > 1. if Cortex-A8, always execute invalidate BTB instruction in
> > > cpu_v7_switch_mm
> >
> > This part still seems to need more investigating for why it's still
> > needed also r3p2 as I describe above. Otherwise we may be hiding some
> > other bug.
> >
> > > 2. For Cortex-A8 revisions affected by 430973, set IBE bit to 1, set it
> > > to 0 for all others. That should happen as soon as possible,
> > > otherwise kernel may crash on affected revisions if thumb-
> > > compiled.
> >
> > Yes this makes sense.
>
> Well, one thing we can do is to tweak the proc-v7*.S such that we detect
> Cortex-A8 separately, and only execute the BTB flush for CA8 processors
> if the errata is enabled. Something like this (untested):
>
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -527,6 +545,16 @@ __v7_ca9mp_proc_info:
> __v7_proc __v7_ca9mp_proc_info, __v7_ca9mp_setup, proc_fns = ca9mp_processor_functions
> .size __v7_ca9mp_proc_info, . - __v7_ca9mp_proc_info
>
> + /*
> + * ARM Ltd. Cortex A8 processor.
> + */
> + .type __v7_ca8_proc_info, #object
> +__v7_ca8_proc_info:
> + .long 0x410fc080
> + .long 0xff0ffff0
> + __v7_proc __v7_ca8mp_proc_info, proc_fns = ca8_processor_functions
> + .size __v7_ca8_proc_info, . - __v7_ca8_proc_info
> +
> #endif /* CONFIG_ARM_LPAE */
>
> /*
Works for me. The above needs the following fix folded in to build:
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -532,7 +532,7 @@ __v7_ca9mp_proc_info:
__v7_ca8_proc_info:
.long 0x410fc080
.long 0xff0ffff0
- __v7_proc __v7_ca8mp_proc_info, proc_fns = ca8_processor_functions
+ __v7_proc __v7_ca8_proc_info, __v7_setup, proc_fns = ca8_processor_functions
.size __v7_ca8_proc_info, . - __v7_ca8_proc_info
#endif /* CONFIG_ARM_LPAE */
Regards,
Tony
next prev parent reply other threads:[~2015-04-07 15:22 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 [this message]
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
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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