Re: xfree86 4.2.1-0pre1v1 available at the X Strike Force

[Richard Zidlicky <rz@linux-m68k.org>]

On Wed, Oct 23, 2002 at 10:23:38AM -0700, Erik van Roode wrote:
> At 09:36 10/22/2002, Branden Robinson wrote:
> 
> >I beseech you to help debug and fix the XFree86 module loader on m68k.
> 
> If I understand correctly the issue with 68040/68060 is cache coherency. 
> When looking
> at the 68040 manual from Motorola, (page 4-10):
> 
>  >      It is imperative that a CPUSHA instruction be executed before the 
> execution of the first
> self-modified instruction.
> 
> (68060 manual has identical text)
> 
> There has been some discussion about cache flushing strategy (last 
> January?), and
> CPUSHA is expensive, but  it should fix the loader?

It would fix the loader, the expensive part is the system call
overhead. CPUSH* are privileged instruction so you need a syscall 
for each flush.
Next thing to try is to use the move16 instruction to flush the
cache, but iirc there is nothing like that on 68020-30.

Richard