[PATCH v5 3/6] arm64: Add framework for legacy instruction emulation

[Catalin Marinas]

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 <punit.agrawal at arm.com>

Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>