Re: JIT emulator needs

[Arjan van de Ven <arjan@infradead.org>]

> > > > and these methods also destroy yourself on any machine with a looser
> > > > cache coherency between I and D-cache....
> > > >
> > > > for all but x86 you pretty much have to do the mprotect() between the
> > > > two states to deal with the cache flushing properly...
> > >
> > > If the instructions to force data write-back and/or to
> > > invalidate the instruction cache are priveleged, yes.
> > > AFAIK, only ARM is that lame.
> >
> > and your program executes this on all the cpus in the system?

no I meant that you had to call your userspace instruction on all cpus,
so on all-but-arm (from the Intel side I know IA64 needs such a flush,
but I'm pretty sure PPC does too)


> I don't recall seeing such code in the libgcc tranpoline
> setup for PowerPC. Either it's not required, or this is
> a rather popular bug.

I suspect it'll be playing under the assumption that going from "no
code" to "code" is fine since the icache is cold.


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