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Subject: Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict
 Indirect Branch Speculation
To: Linux ARM <linux-arm-kernel@lists.infradead.org>
Cc: David Woodhouse <dwmw2@infradead.org>, Ingo Molnar <mingo@kernel.org>,
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 "H . Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
 Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>,
 Joerg Roedel <joro@8bytes.org>, Jun Nakajima <jun.nakajima@intel.com>,
 Laura Abbott <labbott@redhat.com>, LKML <linux-kernel@vger.kernel.org>
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From: Mason <slash.tmp@free.fr>
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Date: Thu, 25 Jan 2018 17:19:04 +0100
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On 23/01/2018 10:30, David Woodhouse wrote:

> Skylake takes predictions from the generic branch target buffer when
> the RSB underflows.

Adding LAKML.

AFAIU, some ARM Cortex cores have the same optimization.
(A9 maybe, A17 probably, some recent 64-bit cores)

Are there software work-arounds for Spectre planned for arm32 and arm64?

Regards.