[Xen-devel] RFC: Cleaning up the Mini-OS namespace

[Martin Lucina <martin@xxxxxxxxxx>]

Hi,

In rumprun-xen [1] we use Mini-OS as a "base firmware" layer in our stack.
Currently we are using a slightly bastardized fork of the xen.git Mini-OS.

We would like to avoid this turning into a permanent fork. Following
previous discussion [2] on and openmirage-devel I would like to coordinate
upstreaming our changes if possible.

The biggest change which needs to be done is cleaning up the Mini-OS
namespace. This is necessary as we link Mini-OS with the application, rump
kernel and NetBSD libc to get a full application stack.

The changes as implemented in a semi-automated fashion for the Mini-OS used
by rumprun-xen can be viewed in the (since merged) pull request at [3]:

- All Mini-OS functions called by rumprun-xen are renamed to minios_* or
  _minios_* for strictly internal functions, except those in the
  blkfront_*, netfront_*, pcifront_* and xenbus_* driver namespaces.
- In the case of drivers, eg. init|shutdown_blkfront are renamed to
  blkfront_*.
- All global variables are either manually made local, or placed under
  the _minios_* namespace, with the exception of HYPERVISOR_shared_info,
  and those variables under driver namespaces kept above.
- All callers are updated to use the new names. Where it makes sense,
  macros such as alloc_page are also renamed into the minios_ namespace.

Questions:

- Is there a general interest in upstreaming this work?
- Upstream Mini-OS provides things we (rumpkernel.org) don't need (stub
  "libc", ...). If we are to move to upstream then we will need to do a
  more general cleanup of Mini-OS to make these pluggable. Again, is there
  upstream interest in this work?
- As there is no formal API for Mini-OS. My changes only address the
  "public" functionality used by rumprun-xen. Other users mileage will
  vary; who else should I coordinate with?
- I have not namespaced macros such as local_irq_save(). Should this be
  done? 
  
  Also, the driver namespaces have been preserved (since I was lazy), these
  should probably be renamed under the minios namespace; it's plausible
  some day someone will try to link an application with a function called
  blkfront_init().

All comments and review welcome.

Martin

[1] http://repo.rumpkernel.org/rumprun-xen
[2] http://thread.gmane.org/gmane.comp.rumpkernel.user/514
[3] https://github.com/rumpkernel/rumprun-xen/pull/10

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