Correct robust mutex / PI futex kernel assumptions (bug 9894)

[Joseph S. Myers]

On Tue, 25 Mar 2014, David Miller wrote:

> > and futex_32.h just uses the asm-generic version, which just returns 
> > -ENOSYS.  Are you saying that if glibc is built for 32-bit plus V9/V8plus, 
> > then the kernel that glibc binary runs under must have been built with 
> > defined(__sparc__) && defined(__arch64__) true?  If so, what is the 
> > relevant cpp condition in userspace for "glibc can assume a kernel with 
> > functional futex_atomic_cmpxchg_inatomic"?
> 
> A 32-bit binary compiled for v9 can only execute on 64-bit kernels.

Thanks for the explanation.  What's the right preprocessor conditional for 
requiring a 64-bit kernel (to replace the "defined __arch64__" in my 
patch)?

-- 
Joseph S. Myers
joseph@codesourcery.com