1. An apparatus, comprising: a memory storing (i) a plurality of functions and (ii) a mapping of locations of the plurality of functions in the memory; a processor configured to: generate a callback to a security function of the plurality of functions in response to a request from a process being executed by the processor, wherein the process (i) is a kernel, (ii) is a boot loader, or (iii) is requesting the security function, wherein the callback is a function call for the security function to execute, in response to the callback, determine a location in the memory of the security function using the mapping, use the mapping to select the security functions of the plurality of functions to execute when operating after booting, and execute the security function upon branching to the location of the security function in the memory according to the mapping.