Date: Fri, 12 Jan 2018 07:37:53 -0700 From: Warner Losh <imp@bsdimp.com> To: Andrew Turner <andrew@freebsd.org> Cc: Marcin Wojtas <mw@semihalf.com>, src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r327876 - in head/sys/arm64: arm64 include Message-ID: <CANCZdfpfEJcxdGeya1_6jT=RKdT8VUw%2BY7Ma2Z=%2Bk6DY_XaG4g@mail.gmail.com> In-Reply-To: <FEDCB2AD-AFF1-4C10-9191-76601A66BC1D@freebsd.org> References: <201801121401.w0CE1cW4058239@repo.freebsd.org> <CAPv3WKcESa_AL=R-BFwef2GXxHcYsnmbUOV3Zx5qL8WdMS-o3Q@mail.gmail.com> <FEDCB2AD-AFF1-4C10-9191-76601A66BC1D@freebsd.org>
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On Fri, Jan 12, 2018 at 7:15 AM, Andrew Turner <andrew@freebsd.org> wrote: > > > On 12 Jan 2018, at 14:10, Marcin Wojtas <mw@semihalf.com> wrote: > > Hi Andrew, > > > > 2018-01-12 15:01 GMT+01:00 Andrew Turner <andrew@freebsd.org>: > > Author: andrew > Date: Fri Jan 12 14:01:38 2018 > New Revision: 327876 > URL: https://svnweb.freebsd.org/changeset/base/327876 > > Log: > Workaround Spectre Variant 2 on arm64. > > We need to handle two cases: > > 1. One process attacking another process. > 2. A process attacking the kernel. > > For the first case we clear the branch predictor state on context switch > between different processes. For the second we do this when taking an > instruction abort on a non-userspace address. > > To clear the branch predictor state a per-CPU function pointer has been > added. This is set by the new cpu errata code based on if the CPU is > known to be affected. > > On Cortex-A57, A72, A73, and A75 we call into the PSCI firmware as newer > versions of this will clear the branch predictor state for us. > > It has been reported the ThunderX is unaffected, however the ThunderX2 is > vulnerable. The Qualcomm Falkor core is also affected. As FreeBSD doesn't > yet run on the ThunderX2 or Falkor no workaround is included for these > CPUs. > > > Regardless ThunderX2 / Falkor work-arounds, do I understand correctly > that pure CA72 machines, such as Marvell Armada 7k/8k are immune to > Variant 2 now? > > > It is my understanding that the A72 will be immune with this patch and an > updated Arm Trusted Firmware as documented in [1]. > > Andrew > > [1] https://github.com/ARM-software/arm-trusted-firmware/ > wiki/ARM-Trusted-Firmware-Security-Advisory-TFV-6 > Are you also working on aarch32 mitigation? Warner
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