Re: SHMLBA and compat tasks

[Arun Sharma <arun.sharma@intel.com>]

On Sat, Feb 28, 2004 at 03:55:29PM -0800, David S. Miller wrote:
> 
> Platforms with virtually indexed caches use SHMLBA of a size such that
> it is the largest cache virtual aliasing factor.  In this way, processes
> with different SHM mappings of the shared writable memory will immediately
> see writes done by other processes and aliases cannot enter the cache due
> to virtual addresses being "just right".

I read that to mean that there is a correctness problem, apart from
performance issues on some platforms.

How about something like:

			else
#ifndef ARCH_HAS_VCACHE
			if (addr & ~PAGE_MASK)
#endif
 				return -EINVAL;

So that platforms with virtually indexed caches are not affected ?

	-Arun