From: gnomes@lxorguk.ukuu.org.uk (Alan Cox)
To: linux-arm-kernel@lists.infradead.org
Subject: [v2,03/11] arm64: Take into account ID_AA64PFR0_EL1.CSV3
Date: Mon, 8 Jan 2018 18:22:20 +0000 [thread overview]
Message-ID: <20180108182220.34233ebc@alans-desktop> (raw)
In-Reply-To: <20180108175100.GW25869@arm.com>
> > On systems that are not vulnerable to variant 3, this is an unnecessary
> > overhead.
>
> KASLR can be bypassed on CPUs that are not vulnerable to variant 3 simply
> by timing how long accesses to kernel addresses from EL0 take -- please read
> the original KAISER paper for details about that attack on x86. kpti
> mitigates that. If you don't care about KASLR, don't enable it (arguably
> it's useless without kpti).
KASLR is primarily of value for remote protection.
Alan
WARNING: multiple messages have this Message-ID (diff)
From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Will Deacon <will.deacon@arm.com>
Cc: Jayachandran C <jnair@caviumnetworks.com>,
Marc Zyngier <marc.zyngier@arm.com>,
linux-arm-kernel@lists.infradead.org, lorenzo.pieralisi@arm.com,
ard.biesheuvel@linaro.org, catalin.marinas@arm.com,
linux-kernel@vger.kernel.org, labbott@redhat.com,
christoffer.dall@linaro.org
Subject: Re: [v2,03/11] arm64: Take into account ID_AA64PFR0_EL1.CSV3
Date: Mon, 8 Jan 2018 18:22:20 +0000 [thread overview]
Message-ID: <20180108182220.34233ebc@alans-desktop> (raw)
In-Reply-To: <20180108175100.GW25869@arm.com>
> > On systems that are not vulnerable to variant 3, this is an unnecessary
> > overhead.
>
> KASLR can be bypassed on CPUs that are not vulnerable to variant 3 simply
> by timing how long accesses to kernel addresses from EL0 take -- please read
> the original KAISER paper for details about that attack on x86. kpti
> mitigates that. If you don't care about KASLR, don't enable it (arguably
> it's useless without kpti).
KASLR is primarily of value for remote protection.
Alan
next prev parent reply other threads:[~2018-01-08 18:22 UTC|newest]
Thread overview: 133+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-05 13:12 [PATCH v2 00/11] arm64 kpti hardening and variant 2 workarounds Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 13:12 ` [PATCH v2 01/11] arm64: use RET instruction for exiting the trampoline Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-06 13:13 ` Ard Biesheuvel
2018-01-06 13:13 ` Ard Biesheuvel
2018-01-08 14:33 ` Will Deacon
2018-01-08 14:33 ` Will Deacon
2018-01-08 14:38 ` Ard Biesheuvel
2018-01-08 14:38 ` Ard Biesheuvel
2018-01-08 14:45 ` Will Deacon
2018-01-08 14:45 ` Will Deacon
2018-01-08 14:56 ` Ard Biesheuvel
2018-01-08 14:56 ` Ard Biesheuvel
2018-01-08 15:27 ` David Laight
2018-01-08 15:27 ` David Laight
2018-01-05 13:12 ` [PATCH v2 02/11] arm64: Kconfig: Reword UNMAP_KERNEL_AT_EL0 kconfig entry Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 13:12 ` [PATCH v2 03/11] arm64: Take into account ID_AA64PFR0_EL1.CSV3 Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-08 7:24 ` [v2,03/11] " Jayachandran C
2018-01-08 7:24 ` Jayachandran C
2018-01-08 9:20 ` Marc Zyngier
2018-01-08 9:20 ` Marc Zyngier
2018-01-08 17:40 ` Jayachandran C
2018-01-08 17:40 ` Jayachandran C
2018-01-08 17:51 ` Will Deacon
2018-01-08 17:51 ` Will Deacon
2018-01-08 18:22 ` Alan Cox [this message]
2018-01-08 18:22 ` Alan Cox
2018-01-09 4:06 ` Jayachandran C
2018-01-09 4:06 ` Jayachandran C
2018-01-09 10:00 ` Will Deacon
2018-01-09 10:00 ` Will Deacon
2018-01-19 1:00 ` Jon Masters
2018-01-19 1:00 ` Jon Masters
2018-01-08 17:52 ` Marc Zyngier
2018-01-08 17:52 ` Marc Zyngier
2018-01-08 17:06 ` Will Deacon
2018-01-08 17:06 ` Will Deacon
2018-01-08 17:50 ` Jayachandran C
2018-01-08 17:50 ` Jayachandran C
2018-01-05 13:12 ` [PATCH v2 04/11] arm64: cpufeature: Pass capability structure to ->enable callback Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 13:12 ` [PATCH v2 05/11] drivers/firmware: Expose psci_get_version through psci_ops structure Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 13:12 ` [PATCH v2 06/11] arm64: Move post_ttbr_update_workaround to C code Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 13:12 ` [PATCH v2 07/11] arm64: Add skeleton to harden the branch predictor against aliasing attacks Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-08 0:15 ` Jon Masters
2018-01-08 0:15 ` Jon Masters
2018-01-08 12:16 ` James Morse
2018-01-08 12:16 ` James Morse
2018-01-08 14:26 ` Will Deacon
2018-01-08 14:26 ` Will Deacon
2018-01-17 4:10 ` Yisheng Xie
2018-01-17 4:10 ` Yisheng Xie
2018-01-17 10:07 ` Will Deacon
2018-01-17 10:07 ` Will Deacon
2018-01-18 8:37 ` Yisheng Xie
2018-01-18 8:37 ` Yisheng Xie
2018-01-19 3:37 ` Li Kun
2018-01-19 3:37 ` Li Kun
2018-01-19 14:28 ` Will Deacon
2018-01-19 14:28 ` Will Deacon
2018-01-22 6:52 ` Li Kun
2018-01-22 6:52 ` Li Kun
2018-01-05 13:12 ` [PATCH v2 08/11] arm64: KVM: Use per-CPU vector when BP hardening is enabled Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 13:12 ` [PATCH v2 09/11] arm64: KVM: Make PSCI_VERSION a fast path Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 13:12 ` [PATCH v2 10/11] arm64: cputype: Add missing MIDR values for Cortex-A72 and Cortex-A75 Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 13:12 ` [PATCH v2 11/11] arm64: Implement branch predictor hardening for affected Cortex-A CPUs Will Deacon
2018-01-05 13:12 ` Will Deacon
2018-01-05 14:46 ` James Morse
2018-01-05 14:46 ` James Morse
2018-01-05 14:57 ` Marc Zyngier
2018-01-05 14:57 ` Marc Zyngier
2018-01-08 6:31 ` [v2, " Jayachandran C
2018-01-08 6:31 ` Jayachandran C
2018-01-08 6:53 ` [PATCH 1/2] arm64: cputype: Add MIDR values for Cavium ThunderX2 CPUs Jayachandran C
2018-01-08 6:53 ` Jayachandran C
2018-01-08 6:53 ` [PATCH 2/2] arm64: Branch predictor hardening for Cavium ThunderX2 Jayachandran C
2018-01-08 6:53 ` Jayachandran C
2018-01-08 16:46 ` Will Deacon
2018-01-08 16:46 ` Will Deacon
2018-01-08 17:19 ` Jayachandran C
2018-01-08 17:19 ` Jayachandran C
2018-01-08 17:23 ` Will Deacon
2018-01-08 17:23 ` Will Deacon
2018-01-09 2:26 ` Jayachandran C
2018-01-09 2:26 ` Jayachandran C
2018-01-09 9:53 ` Will Deacon
2018-01-09 9:53 ` Will Deacon
2018-01-09 12:47 ` [PATCH v2] " Jayachandran C
2018-01-09 12:47 ` Jayachandran C
2018-01-16 21:50 ` Jon Masters
2018-01-16 21:52 ` Jon Masters
2018-01-16 23:45 ` Jayachandran C
2018-01-17 18:34 ` Jon Masters
2018-01-17 18:34 ` Jon Masters
2018-01-18 13:53 ` Will Deacon
2018-01-18 13:53 ` Will Deacon
2018-01-18 17:56 ` Jayachandran C
2018-01-18 17:56 ` Jayachandran C
2018-01-18 18:27 ` Jon Masters
2018-01-18 18:27 ` Jon Masters
2018-01-18 23:28 ` Jayachandran C
2018-01-18 23:28 ` Jayachandran C
2018-01-19 1:17 ` Jon Masters
2018-01-19 1:17 ` Jon Masters
2018-01-19 12:22 ` [PATCH v3 1/2] " Jayachandran C
2018-01-19 12:22 ` Jayachandran C
2018-01-19 12:22 ` [PATCH v3 2/2] arm64: Turn on KPTI only on CPUs that need it Jayachandran C
2018-01-19 12:22 ` Jayachandran C
2018-01-22 11:41 ` Will Deacon
2018-01-22 11:41 ` Will Deacon
2018-01-22 11:51 ` Ard Biesheuvel
2018-01-22 11:51 ` Ard Biesheuvel
2018-01-22 11:55 ` Will Deacon
2018-01-22 11:55 ` Will Deacon
2018-01-22 18:59 ` Jon Masters
2018-01-22 18:59 ` Jon Masters
2018-01-19 19:08 ` [PATCH v3 1/2] arm64: Branch predictor hardening for Cavium ThunderX2 Jon Masters
2018-01-19 19:08 ` Jon Masters
2018-01-22 11:33 ` Will Deacon
2018-01-22 11:33 ` Will Deacon
2018-01-22 19:00 ` Jon Masters
2018-01-22 19:00 ` Jon Masters
2018-01-23 9:51 ` Will Deacon
2018-01-23 9:51 ` Will Deacon
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