From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Fri, 14 Nov 2014 18:32:41 +0000 Subject: [PATCHv4 4/5] arm64: Emulate CP15 Barrier instructions In-Reply-To: <1415792692-11189-5-git-send-email-punit.agrawal@arm.com> References: <1415792692-11189-1-git-send-email-punit.agrawal@arm.com> <1415792692-11189-5-git-send-email-punit.agrawal@arm.com> Message-ID: <20141114183240.GF6755@e104818-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Nov 12, 2014 at 11:44:51AM +0000, Punit Agrawal wrote: > The CP15 barrier instructions (CP15ISB, CP15DSB and CP15DMB) are > deprecated in the ARMv7 architecture, superseded by ISB, DSB and DMB > instructions respectively. Some implementations may provide the > ability to disable the CP15 barriers by disabling the CP15BEN bit in > SCTLR_EL1. If not enabled, the encodings for these instructions become > undefined. > > To support legacy software using these instructions, this patch > register hooks to - > * emulate CP15 barriers and warn the user about their use > * toggle CP15BEN in SCTLR_EL1 > > Signed-off-by: Punit Agrawal Reviewed-by: Catalin Marinas