From mboxrd@z Thu Jan 1 00:00:00 1970 From: matthijsvanduin@gmail.com (Matthijs van Duin) Date: Sun, 5 Apr 2015 06:13:47 +0200 Subject: ARM errata 430973 on multi platform kernels In-Reply-To: <20150403225212.GY10805@atomide.com> References: <55197A12.1050009@bitmer.com> <20150330164237.GJ10805@atomide.com> <55198BA4.5010207@bitmer.com> <20150330175051.GK10805@atomide.com> <20150331123233.GA15103@earth> <20150401194734.GT10805@atomide.com> <20150403163553.GA16247@earth> <551F0F50.1030701@gmail.com> <20150403221517.GX10805@atomide.com> <551F186B.90608@gmail.com> <20150403225212.GY10805@atomide.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 4 April 2015 at 00:52, Tony Lindgren wrote: > Right, it affects n900 for sure. My point is that it also seems to > affect 37xx versions not listed to suffer from this issue. They shouldn't... erratum 430973 only affected Cortex-A8 r1, and the dm37xx should have an r3p2 right? A word of caution though: at least on the DM814x and AM335x, secure ROM sets bit 6 (IBE) in the Auxiliary Control Register, thereby enabling BTB invalidate instructions (which normally execute as nops). This is presumably a leftover of the erratum 430973 workaround, but it means there is a risk of running afoul of erratum 687067 if BTB invalidate by MVA instructions are actually used. I would actually suggest clearing IBE if it set on Cortex-A8 r2 or later processors and a secure monitor call is available to do so (there is on the DM814x and AM335x, dunno about the 37xx), also for performance reasons: BTB invalidates are quite expensive instructions (when enabled). Matthijs