New 745x errata

Tom Rini trini at
Tue Nov 18 02:04:09 EST 2003

On Mon, Nov 17, 2003 at 02:57:53PM +0000, Adrian Cox wrote:
> On Fri, 2003-11-14 at 16:24, Tom Rini wrote:
> > On Thu, Nov 13, 2003 at 11:05:17AM +0000, Adrian Cox wrote:
> > > 1) The BTIC doesn't work reliably: it can cause execution of corrupted
> > > instructions. (This is listed in the errata for the 7450 and 7457, but
> > > not for the 7455. I'll only believe that the 7455 escaped this bug if I
> > > hear confirmation out of Motorola.)
> >
> > I've done the opposite in something I've been waiting for 2.4.24-pre to
> > come out to fix.  But I agree that it is odd that it's not listed on the
> > 7455.
> Still no word back from Motorola on the 7455. I think your patch should
> go in.
> Any opinion on the dcbt issue?  It looks like it could provide a way for
> a malicious userspace application to crash the machine, though it needs
> a combination of:
> 1) good timing
> 2) a peripheral that would be confused by an extra read cycle

[ My knowledge of Motorola CPU errata has been temprorarily replaced
with other things, so I don't recall the details just yet of the dbct
issue ]
It depends on what the fix is.  For example, Linus just fixed a
theoretical race that has a 1-3 cycle (depending on x86 cpu I think he
said) race because he happened to be in there anyhow (and it turns out
the fix is easy).

Tom Rini

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