The four ports of Inferno to Cortex-M4 and M7 processors that I've worked on shared a fair amount of code. This was the result of taking each port and using it as the basis for the next. Ideally, all the common code would be maintained in one place and reused, just as the SA1110 ports all reuse the code in the os/sa1110 directory.
The one port that's left behind for now is the SAMD51 port, since I can't test it. That's still available in its own branch for now, though I might merge it into the cortexm branch and leave it using duplicate code and definitions.
An overview of these ports and others can be found on the Inferno Ports page.