[PATCH][SPARC] missing membar in niagara2_memcpy

[David Miller]

From: jose.marchesi@oracle.com (Jose E. Marchesi)
Date: Thu, 15 May 2014 19:31:43 +0200

> Several system tests of a certain (very data intensive) program crashed
> as soon as it started to use multilib/niagara2_memcpy, due to memory
> corruption.  They run just fine after this patch is applied.
> 
> We also observed that jar would occasionally raise
> java.util.zip.ZipException.  This was due to the fact the last two bytes
> of a buffer were not apparently being copied by memcpy.  Again, this
> patch fixes that problem.
> 
>     The member is extremely expensive and I avoided it intentionally.
> 
> Yes I suspected that, given how carefully that code is written.  We are
> aware that membars are painful on the T2 (any membar, because all
> flavors are mapped to #Sync) but the risk of overlaps is not only
> theoretical in this case, unfortunately :(

Ok I'll install this fix after some testing and update the copy of the
same code in the kernel as well, thanks.