From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@armlinux.org.uk (Russell King - ARM Linux) Date: Thu, 19 Jul 2018 14:32:22 +0100 Subject: arm: v4.18-rc5 with cpuidle on TC2 (A7 boot) spectre v2 issue In-Reply-To: <20180719100109.GH17271@n2100.armlinux.org.uk> References: <2abc6c11-2e8c-a4ea-6911-0f495d90ace6@arm.com> <20180719100109.GH17271@n2100.armlinux.org.uk> Message-ID: <20180719133222.GL17271@n2100.armlinux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jul 19, 2018 at 11:01:10AM +0100, Russell King - ARM Linux wrote: > On Thu, Jul 19, 2018 at 11:42:50AM +0200, Dietmar Eggemann wrote: > > Hi, > > > > running v4.18-rc5 (plus still missing "power: vexpress: fix corruption in > > notifier registration", otherwise I get this rcu_sched stall issue) on TC2 > > (A7 boot) with vanilla multi_v7_defconfig plus > > CONFIG_ARM_BIG_LITTLE_CPUIDLE=y gives me continuous: > > > > ... > > CPUX: Spectre v2: incorrect context switching function, system vulnerable > > ... > > > > messages. > > > > Work around is to disable CONFIG_HARDEN_BRANCH_PREDICTOR. > > or disable big.Little if you want the hardening. > > The choices are currently either protection against Spectre or big.Little > support since the two are mutually exclusive at the moment. An alternative would be to give the patches in the attachment a test. They're not finished yet, so I haven't sent them out, but still worth testing. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up According to speedtest.net: 13Mbps down 490kbps up -------------- next part -------------- A non-text attachment was scrubbed... Name: bl.tar.xz Type: application/x-xz Size: 4120 bytes Desc: not available URL: