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From: Jon Masters <jcm@jonmasters.org>
To: Marc Zyngier <marc.zyngier@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Cc: Will Deacon <will.deacon@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Dominik Brodowski <linux@dominikbrodowski.net>,
	Julien Grall <julien.grall@arm.com>,
	Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH v2 05/17] arm64: Add 'ssbd' command-line option
Date: Sat, 9 Jun 2018 08:53:08 -0400	[thread overview]
Message-ID: <e1b89362-ba94-ead9-a930-eac0e1b3ffba@jonmasters.org> (raw)
In-Reply-To: <20180529121121.24927-6-marc.zyngier@arm.com>

On 05/29/2018 08:11 AM, Marc Zyngier wrote:

> +	ssbd=		[ARM64,HW]
> +			Speculative Store Bypass Disable control
> +
> +			On CPUs that are vulnerable to the Speculative
> +			Store Bypass vulnerability and offer a
> +			firmware based mitigation, this parameter
> +			indicates how the mitigation should be used:
> +
> +			force-on:  Unconditionally enable mitigation for
> +				   for both kernel and userspace
> +			force-off: Unconditionally disable mitigation for
> +				   for both kernel and userspace
> +			kernel:    Always enable mitigation in the
> +				   kernel, and offer a prctl interface
> +				   to allow userspace to register its
> +				   interest in being mitigated too.

This should be "spec_store_bypass_disable" and it should have the same
parameters as on x86: "on", "off", "auto". Why not just add "kernel"?
(we had a "kernel" early on for x86 as well, and it might still end up
coming back anyway). If there's a /compelling/ reason to have the Arm
parameter differ, then it should still recognize the x86 parameter,
similarly to how POWER also does that for cross-arch consistency.

We'll add the x86 parameter way of doing it to RHEL anyway.

Jon.

  reply	other threads:[~2018-06-09 13:19 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-29 12:11 [PATCH v2 00/17] arm64 SSBD (aka Spectre-v4) mitigation Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 01/17] arm/arm64: smccc: Add SMCCC-specific return codes Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 02/17] arm64: Call ARCH_WORKAROUND_2 on transitions between EL0 and EL1 Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 03/17] arm64: Add per-cpu infrastructure to call ARCH_WORKAROUND_2 Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 04/17] arm64: Add ARCH_WORKAROUND_2 probing Marc Zyngier
2018-05-29 13:39   ` Suzuki K Poulose
2018-05-29 12:11 ` [PATCH v2 05/17] arm64: Add 'ssbd' command-line option Marc Zyngier
2018-06-09 12:53   ` Jon Masters [this message]
2018-06-09 13:19     ` Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 06/17] arm64: ssbd: Add global mitigation state accessor Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 07/17] arm64: ssbd: Skip apply_ssbd if not using dynamic mitigation Marc Zyngier
2018-06-09 13:03   ` Jon Masters
2018-06-09 13:21     ` Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 08/17] arm64: ssbd: Restore mitigation status on CPU resume Marc Zyngier
2018-05-29 13:35   ` Mark Rutland
2018-05-29 12:11 ` [PATCH v2 09/17] arm64: ssbd: Introduce thread flag to control userspace mitigation Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 10/17] arm64: ssbd: Add prctl interface for per-thread mitigation Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 11/17] arm64: KVM: Add HYP per-cpu accessors Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 12/17] arm64: KVM: Add ARCH_WORKAROUND_2 support for guests Marc Zyngier
2018-06-09 13:09   ` Jon Masters
2018-06-09 13:21     ` Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 13/17] arm64: KVM: Handle guest's ARCH_WORKAROUND_2 requests Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 14/17] arm64: KVM: Add ARCH_WORKAROUND_2 discovery through ARCH_FEATURES_FUNC_ID Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 15/17] arm64: Add test_and_clear_flag and set_flag atomic assembler primitives Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 16/17] arm64: ssbd: Enable delayed setting of TIF_SSBD Marc Zyngier
2018-05-29 12:11 ` [PATCH v2 17/17] arm64: ssbd: Implement arch_seccomp_spec_mitigate Marc Zyngier
2018-05-30 15:58 ` [PATCH v2 00/17] arm64 SSBD (aka Spectre-v4) mitigation Will Deacon
2018-05-31 16:41 ` Catalin Marinas
2018-05-31 16:55   ` Marc Zyngier
2018-06-09 13:16 ` Jon Masters

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