RETURN-TARGET RESTRICTIVE RETURN FROM PROCEDURE INSTRUCTIONS, PROCESSORS, METHODS, AND SYSTEMS

A processor includes a decode unit to decode a return target restrictive return from procedure (RTR return) instruction. A return target restriction unit is responsive to the RTR return instruction to determine whether to restrict an attempt by the RTR return instruction to make a control flow transfer to an instruction at a return address corresponding to the RTR return instruction. The determination is based on compatibility of a type of the instruction at the return address with the RTR return instruction and based on compatibility of first return target restrictive information (RTR information) of the RTR return instruction with second RTR information of the instruction at the return address. A control flow transfer unit is responsive to the RTR return instruction to transfer control flow to the instruction at the return address when the return target restriction unit determines not to restrict the attempt.