From mboxrd@z Thu Jan 1 00:00:00 1970 From: ezequiel.garcia@free-electrons.com (Ezequiel Garcia) Date: Sat, 22 Jun 2013 12:44:22 -0300 Subject: [PATCH v7] ARM PJ4B: Add support for errata 4742 In-Reply-To: <1371828664-3681-2-git-send-email-gregory.clement@free-electrons.com> References: <1371828664-3681-1-git-send-email-gregory.clement@free-electrons.com> <1371828664-3681-2-git-send-email-gregory.clement@free-electrons.com> Message-ID: <20130622154421.GA475@localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Greg, On Fri, Jun 21, 2013 at 05:31:04PM +0200, Gregory CLEMENT wrote: > This commit fixes the regression on Armada 370 (the kernal hang during > boot) introduced by the commit: "ARM: 7691/1: mm: kill unused > TLB_CAN_READ_FROM_L1_CACHE and use ALT_SMP instead". > > When coming out of either a Wait for Interrupt (WFI) or a Wait for > Event (WFE) IDLE states, a specific timing sensitivity exists between > the retiring WFI/WFE instructions and the newly issued subsequent > instructions. This sensitivity can result in a CPU hang scenario. The > workaround is to insert either a Data Synchronization Barrier (DSB) or > Data Memory Barrier (DMB) command immediately after the WFI/WFE > instruction. > > This commit was based on the work of Lior Amsalem, but heavily > modified to apply the errata fix dynamically according to the > processor type thanks to the suggestions of Russell King and Nicolas > Pitre. > > Signed-off-by: Gregory CLEMENT > Reviewed-by: Will Deacon > Cc: This patch doesn't seem to apply on any 3.10-rcX; maybe I'm doing something wrong, but could you double-check this? Thanks, -- Ezequiel Garc?a, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com