ARM: enable interpreter, add locks code

[Andrew Haley]

Daniel Jacobowitz writes:
 > On Wed, Jul 11, 2007 at 10:10:19PM -0000, Boehm, Hans wrote:
 > > The problem of course is that this works perectly for some use cases,
 > > e.g. when it's used to implement test-and-set for a spin-lock.  And it
 > > probably almost never fails on a uniprocessor.  I'd expect it to do
 > > fairly badly on a multicore processor for use cases for which the
 > > atomicity really matters.
 > 
 > Yes, that's right.  There has only been ARM multi-core support in the
 > Linux kernel for a brief while (the last year or so); over the ten
 > year life of the ARM LinuxThreads port I believe this issue was
 > discovered by inspection twice, but encountered in practice never.

Quite.  There are many things that we can worry about, but I'm quite
happy to wait for this to be fixed by the LinuxThreads people.

Andrew.