RFC: linux-aarch64 and LSE support

[Kim Barrett]

> On Sep 23, 2022, at 2:52 PM, dean.long at oracle.com wrote:
> 
> On 9/23/22 5:58 AM, Andrew Haley wrote:
>> On 9/23/22 12:40, dean.long at oracle.com wrote:
>>> I have to admit it is a bit surprising and counter-intuitive to me to
>>> not treat the CASAL as atomic.  If the memory model allows the 2nd store
>>> to be moved "inside" the CASAL, then that means it might be impossible
>>> to provide a total order of the AArch64 instructions that reproduces the
>>> observed memory effects, and that makes me wonder if it would break
>>> tools like "rr".
>> Is that an "all the world's an x86" kind of intuition, though? We're
>> all influenced more than we know by our history. Even Aleksey was
>> surprised by
>> https://twitter.com/shipilev/status/1400154160918581248
>> in which AArch64 produces "Interesting  Whoa".
> 
> For me it's more getting stuck thinking in terms of machine instructions.  If I can conceptually make the switch to "operations" and memory effects, then everything is fine.
> 
> dl
> 
> PS - I didn't mean to derail this thread!

You haven’t derailed anything.  I’m having similar thoughts and trying to figure out the story might be.
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