* Andy Lutomirski <[email protected]> wrote:
> From: Denys Vlasenko <[email protected]>
>
> Avoid redundant load of %r11 (it is already loaded a few instructions before).
Note, this comment is incorrect:
> Do not needlessly increment %rsp - we are going to return to
> userspace via SYSRET, this insn doesn't use stack for return.
The reason we don't need to increment %rsp because in the very next
instruction we are restoring it, and then do we execute a SYSRET:
So instead of:
add $0x80, %rsp
mov 0x18(%rsp), %rsp
we can do a simplified:
mov 0x98(%rsp), %rsp
to get the same result.
(I've clarified the changelog with this when applying the patch.)
Thanks,
Ingo
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