From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Thu, 20 Nov 2014 16:30:38 +0000 Subject: [PATCH v5 3/6] arm64: Add framework for legacy instruction emulation In-Reply-To: <1416310887-14649-4-git-send-email-punit.agrawal@arm.com> References: <1416310887-14649-1-git-send-email-punit.agrawal@arm.com> <1416310887-14649-4-git-send-email-punit.agrawal@arm.com> Message-ID: <20141120163037.GC5447@e104818-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Nov 18, 2014 at 11:41:24AM +0000, Punit Agrawal wrote: > Typically, providing support for legacy instructions requires > emulating the behaviour of instructions whose encodings have become > undefined. If the instructions haven't been removed from the > architecture, there maybe an option in the implementation to turn > on/off the support for these instructions. > > Create common infrastructure to support legacy instruction > emulation. In addition to emulation, also provide an option to support > hardware execution when supported. The default execution mode (one of > undef, emulate, hw exeuction) is dependent on the state of the > instruction (deprecated or obsolete) in the architecture and > can specified at the time of registering the instruction handlers. The > runtime state of the emulation can be controlled by writing to > individual nodes in sysctl. The expected default behaviour is > documented as part of this patch. > > Signed-off-by: Punit Agrawal Reviewed-by: Catalin Marinas