* Dan Williams <[email protected]> wrote:
> Quoting Linus:
>
> "Honestly, I'd rather get rid of the fast-path entirely. Compared to
> all the PTI mess, it's not even noticeable.
>
> And if we ever get CPU's that have this all fixed, we can re-visit
> introducing the fastpath. But this is all very messy and it doesn't
> seem worth it right now.
>
> If we get rid of the fastpath, we can lay out the slow path slightly
> better, and get rid of some of those jump-overs. And we'd get rid of
> the ptregs hooks entirely.
>
> So we can try to make the "slow" path better while at it, but I
> really don't think it matters much now in the post-PTI era. Sadly."
Please fix the title to have the proper prefix and to reference the function that
is actually modified by the patch, i.e. something like:
s/ x86: remove the syscall_64 fast-path
/ x86/entry/64: Remove the entry_SYSCALL_64() fast-path
With the title fixed:
Reviewed-by: Ingo Molnar <[email protected]>
Thanks,
Ingo
> On Jan 28, 2018, at 1:29 AM, Ingo Molnar <[email protected]> wrote:
>
>
> * Dan Williams <[email protected]> wrote:
>
>> Quoting Linus:
>>
>> "Honestly, I'd rather get rid of the fast-path entirely. Compared to
>> all the PTI mess, it's not even noticeable.
>>
>> And if we ever get CPU's that have this all fixed, we can re-visit
>> introducing the fastpath. But this is all very messy and it doesn't
>> seem worth it right now.
>>
>> If we get rid of the fastpath, we can lay out the slow path slightly
>> better, and get rid of some of those jump-overs. And we'd get rid of
>> the ptregs hooks entirely.
>>
>> So we can try to make the "slow" path better while at it, but I
>> really don't think it matters much now in the post-PTI era. Sadly."
>
> Please fix the title to have the proper prefix and to reference the function that
> is actually modified by the patch, i.e. something like:
>
> s/ x86: remove the syscall_64 fast-path
> / x86/entry/64: Remove the entry_SYSCALL_64() fast-path
>
> With the title fixed:
>
> Reviewed-by: Ingo Molnar <[email protected]>
I have a very similar but not quite identical version I'll send out shortly. The difference is that I fixed the silly prologue.
>
> Thanks,
>
> Ingo