[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <cb7544e2-bd85-df4c-1f48-0afeedefc962@arm.com>
Date: Wed, 30 Jan 2019 15:00:28 +0000
From: James Morse <james.morse@....com>
To: "Zhang, Lei" <zhang.lei@...fujitsu.com>
Cc: 'Catalin Marinas' <catalin.marinas@....com>,
"'linux-kernel@...r.kernel.org'" <linux-kernel@...r.kernel.org>,
'Mark Rutland' <mark.rutland@....com>,
"'linux-arm-kernel@...ts.infradead.org'"
<linux-arm-kernel@...ts.infradead.org>,
"'will.deacon@....com'" <will.deacon@....com>
Subject: Re: [PATCH v3 0/1] arm64: Add workaround for Fujitsu A64FX erratum
010001
Hi!
On 01/29/2019 12:29 PM, Zhang, Lei wrote:
> On some variants of the Fujitsu-A64FX cores ver(1.0, 1.1),
> memory accesses may cause undefined fault (Data abort, DFSC=0b111111).
> This problem will be fixed by next version of Fujitsu-A64FX.
>
> This fault occurs under a specific hardware condition
> when a load/store instruction perform an address translation using:
> case-1 TTBR0_EL1 with TCR_EL1.NFD0 == 1.
> case-2 TTBR0_EL2 with TCR_EL2.NFD0 == 1.
> case-3 TTBR1_EL1 with TCR_EL1.NFD1 == 1.
> case-4 TTBR1_EL2 with TCR_EL2.NFD1 == 1.
> And this fault occurs completely spurious.
>
> Since TCR_ELx.NFD1 is set to '1' at the kernel in versions
> past 4.17, the case-3 or case-4 may happen.
e03e61c3173c ("arm64: kaslr: Set TCR_EL1.NFD1 when
CONFIG_RANDOMIZE_BASE=y") ?
So you'd never see it if you disabled CONFIG_RANDOMIZE_BASE?
Thanks,
James
Powered by blists - more mailing lists