l4_unmap now returns -1 if given range was only partially unmapped.
do_munmap() now only unmaps address ranges that have correspondence in
the unmapped vmas. Trying to unmap regions with no correspondent vmas
causes problems in corner cases, e.g. mm0 that tries to mmap its own
address space during initialisation would unmap its whole address space
and fail to execute.
do_munmap currently shrinks, splits, destroys vmas and unmaps the given
virtual address range from the task. Unmapped pages may go completely unused
but page reclamation will be done in another part of the pager rather than
directly on the munmap instance.
- Fixed do_mmap() so that it returns mapped address, and various bugs.
- A child seems to fork with new setup, but with incorrect return value.
Need to use and test exregs() for fork + clone.
- Shmat searches an unmapped area if input arg is invalid, do_mmap()
should do this.
- fixed is_err(x), was evaluating x twice, resulting in calling a
function x twice.
- Divided task initialisation into multiple parts.
- MM0 now creates a tcb for itself and maintains memory regions of its own.
- MM0's tcb is used for mmapping other tasks' regions. MM0 mmaps and prefaults
those regions, instead of the typical mmap() and fault approach used by
non-pager tasks.
For example there's an internal shmget_shmat() path to map in other tasks'
shm utcbs. Those mappings are then prefaulted into mm0's address space using
the default fault handling path.
- FS0 now reads task data into its utcb from mm0 via a syscall.
FS0 shmat()s to utcbs of other tasks, e.g. mm0 and test0.
FS0 then crashes, that is to be fixed and where this commit is left last.
