Re: [patch 00/38] x86/retbleed: Call depth tracking mitigation

[Joao Moreira]

> Ok. I don't know the context, but I was thinking along the lines of
> the same hash value perhaps being used multiple times because it has
> the same function type.  Then using the "addl" trick means that the
> hash value in %r10 will be changing and cannot be re-used.

Fwiiw, even if %r10 value was not being destroyed by the "addl", the 
call right after the check implies that you cannot trust the contents of 
%r10 anymore (it may have been messed up within the called function).