Is it possible to interact with the processor bypassing the OS?

Question

linux

In general, there is a microcontroller for which the program is compiled (in the form of a bin file), Linux is also launched on this microcontroller.
Tell me if it is possible to run this program in parallel with linux or from Linux itself?
And if possible, how?

Answer 1

Much is not clear... What does the program "assembled" mean, where does it lie, what does it mean "in parallel" and what is the processor architecture?
As a first approximation, the answers are:
- in Linux, you can run the program by making the file executable.
- if this program is used for direct interaction with hardware (such as firmware), then you can try to edit the Linux bootloader so that there is a choice - to load Linux or this firmware.
More specific answers require more specific questions :)