Multi-threaded apps can now wait on children to destroy.
WAIT_ON is useful when a child exists with an exit code and the pager
of the child does not want to take the hassle of destorying it via an
ipc. It provides an alternative method of synchronous thread destruction,
where the child destroys itself directly rather than the parent issuing
a destroy on it explicitly.
Pagers can now share their own private capabilities with their
paged children, or their siblings with whom they have a common pager
ancestor.
Added flags CAP_SHARE_CHILD and CAP_SHARE_SIBLINGS for that.
Notion of pager hierarchy introduced using the existing but unused
pagerid field.
Thread creation now has two more flags TC_AS_PAGER and TC_SHARE_PAGER.
The former sets creator as pager, the latter sets creator's pager as pager.
Thread group capability sharing now correctly carries shared capabilities
to the thread group leader's tgr_cap_list list, and this list is checked
during capability checking.
Added setting of utcb address to l4_thread_control.
This is going to be moved to exchange_registers() since we need to pass
both the utcb physical and virtual address and exregs fits such context
modification better than thread_control.
- Directory creation, file read/write is OK.
- Cannot reuse old task's fds. They are not recycled for some reason.
- Problems with fork/clone/exit. They fail for a reason.
- Added mutex_trylock()
- Implemented most of exchange_registers()
- thread_control() now needs a lock for operations that can modify thread context.
- thread_start() does not initialise scheduler flags, now done in thread_create.
TODO:
- Fork/clone'ed threads should retain their context in tcb, not syscall stack.
- exchange_registers() calls in userspace need cleaning up.
