Re: SharedUserData

[David Laight]

On Wed, Apr 03, 2002 at 09:49:07AM +0200, Laurent Pinchart wrote:
> Hi everybody,
>
> I need to implement the SharedUserData, which is a page of memory 
> located at (KERNEL_BASE - 0x10000) shared between user space (read-only 
> access) and kernel space.

I don't know how to get the 'page fault' trap for a 'valid' user
page on all systems that wine might run on.  Certainly the assumption
that (KERNEL_BASE - 0x10000) is available is probably false...

However you don't actually need a valid user address, a kernel
address (ie one that is always invalid) will do.
Catching SIGSEGV might be enough - but I'm not totally
certain how you can get the value back into the main
process context (emulate the instruction and modify the
saved program counter ????)

David