Apparatuses, methods and storage media associated with multiple processor modes execution are described herein. In embodiments, an apparatus may include a processor with a plurality of processor modes, including a first processor mode to address a first address space, and a second processor mode to address a second address space, the second address space including the first address space. The apparatus may further include a signal handler to handle a signal from a kernel, in the first processor mode; and a signal handler wrapper to switch the processor to the second processor mode on delivery of the signal from the kernel, save a current extra context of the second processor mode from the second register file to a user stack, switch the processor back to the first processor mode, then invoke the signal handler to handle the signal. Other embodiments may be described or claimed.