[Vm-dev] Immutability through hardware

[stephane ducasse]

On May 9, 2011, at 2:16 PM, Igor Stasenko wrote:

> 
> Just a follow-up to recent thread.
> 
> Suppose that we have new object format which supports multiple memory regions.
> I.e.
> eden space
> old space
> pinned space
> ...
> and
> immutable space
> 
> so, instead of adding a flag per object whether its immutable or not,
> and then check this flag every time there is a write attempt,
> we could simply let hardware handle this.
> And immutable space is a memory region with read-only access, So once
> placed & sealed , any attempt to write, we lead to a hardware
> exception,
> which can be nicely handled :)

I would love that to play with secure object space.

> 
> So, we will have a single entry point for all write access , and don't
> need to spread an immutability logic all over the places.
> And of course hardware 'check if memory is writeable' is much faster
> than software one.
> 
> What you think?
> 
> -- 
> Best regards,
> Igor Stasenko AKA sig.