Separated vfs file as a specific file. vm file is not always a vfs file.
Updated the README
sys_open was not returning back to client, added that.
Added comments for future vfs additions.
Tasks boot fine up to doing ipc using their utcbs.
UTCB PLAN:
- Push ipc registers into private environment instead of a shared utcb,
but map-in a shared utcb to pass on long data to server tasks.
- Shared utcb has unique virtual address for every thread.
- Forked child does inherit parent's utcb, but cannot use it to communicate to
any server. It must explicitly obtain its own utcb for that.
- Clone could have a flag to explicitly not inherit parent utcb, which is the
right thing to do.
- MM0 serves a syscall to obtain self utcb.
- By this method, upon forks tasks don't need to map-in a utcb unless they want
to pass long data.
Next issues: For every read fault, the fault must traverse the
vma's object stack until the page is found. The problem was that
we were only searching the first object, that object was a writable
shadow, and the shadow didn't have the read-only page, and the 0
return value was interpreted with IS_ERR() and failed, so address
0 was mapped into the location, and QEMU blew off.
