1. A data processing system, comprising: data processing circuitry; a cache memory; and memory access circuitry, the memory access circuitry operative to perform the steps of: assigning a memory address region to be allocated in the cache memory with a predefined initialization value; allocating a portion of the cache memory to the assigned memory address region only after the data processing circuitry first attempts to perform a memory access on a memory address within the assigned memory address region; and initializing the allocated portion of the cache memory with the predefined initialization value.