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Date:   Thu, 25 Jan 2018 18:16:16 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Mason <slash.tmp@free.fr>
Cc:     Linux ARM <linux-arm-kernel@lists.infradead.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        KarimAllah Ahmed <karahmed@amazon.de>,
        Andi Kleen <ak@linux.intel.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andy Lutomirski <luto@kernel.org>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Ashok Raj <ashok.raj@intel.com>,
        Asit Mallick <asit.k.mallick@intel.com>,
        Borislav Petkov <bp@suse.de>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Hansen <dave.hansen@intel.com>,
        "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>
Subject: Re: [RFC 09/10] x86/enter: Create macros to restrict/unrestrict
 Indirect Branch Speculation
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On Thu, Jan 25, 2018 at 05:19:04PM +0100, Mason wrote:
> 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?

Yes, I think they are currently burried in one of the arm64 trees, and
they have been posted to the mailing list a few times in the past.

thanks,

greg k-h