RFR(m): 8220351: Cross-modifying code

[Andrew Haley]

On 3/14/19 6:18 PM, Andrew Haley wrote:
> I have an idea that might work. Let's say that icache::flush(),
> executed whenever we patch code, increments a global patching
> counter. When a Java thread returns from a handshake, it compares a
> thread-local copy of the old value of the patching counter with the
> current value. If they are different, do whatever local fencing is
> necessary and record the current value of the patching counter.

And, just to complicate this even more, on some processors you'd not
only need to to do local fencing but you might need to know which
memory addresses had changed.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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