An apparatus, and computer program product are disclosed in a processor for dynamically, during runtime, allocating memory for in-memory hardware tracing. The processor is included within a data processing system. The processor includes multiple processing units that are coupled together utilizing a system bus. The processing units include a memory controller that controls a system memory. A particular size of the system memory is determined that is needed for storing trace data. A hardware trace facility requests, dynamically after the data processing system has completed booting, the particular size of the system memory to be allocated to the hardware trace facility for storing trace data that is captured by the hardware trace facility. The firmware selects particular locations within the system memory. All of the particular locations together are the particular size. The firmware allocates the particular locations for use exclusively by the hardware trace facility.