On Fri, Feb 11, 2011 at 03:45:51PM -0500, Nicolas Pitre wrote:

The patch below is making the code more straight forward regardless of 
any swp emulation issues.

I don't know where you get that idea from.  What it does is make a kernel
built with a standard set of options have differing behaviour on v7 and
pre-v7 architectures.

On v7 architectures, the vectors page and user pages all become read only
to SVC mode.  On pre-v7 architectures on the same kernel, they are read-
write to SVC mode.

What we have now is that these pages are only read-only when CPU domains
are turned off - for everything.  So we know that if CPU domains are
enabled, it's read/write, otherwise it's read only.  That's more
straight forward than what this patch creates IMHO.