Re: [PATCH 2/2] x86/time: add CF-clobber annotations

[Jan Beulich <jbeulich@xxxxxxxx>]

On 01.03.2022 15:35, Andrew Cooper wrote:
> On 01/03/2022 14:24, Andrew Cooper wrote:
>> On 01/03/2022 14:18, Jan Beulich wrote:
>>> On 01.03.2022 14:18, Andrew Cooper wrote:
>>>> On 01/03/2022 11:06, Jan Beulich wrote:
>>>>> With bed9ae54df44 ("x86/time: switch platform timer hooks to altcall")
>>>>> in place we can further arrange for ENDBR removal from the functions no
>>>>> longer subject to indirect calls. Note that plt_tsc is left untouched,
>>>>> for not holding any pointer eligible for ENDBR removal.
>>>> I'd be tempted to include it, for consistency sake alone.
>>>>
>>>> It is less likely to go wrong in the future if another hook is introduced.
>>> Can do, sure.
>>>
>>>>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>>>> With the commit message, I'm not not certain if this is linked to the
>>>> previous patch.
>>>>
>>>> Overall it looks fine, but I'd like to get clarity on this point.
>>> Converting read_tsc() was discussed (with Roger) earlier on, so I'd
>>> view this as a separate change. As said in reply to your comments on
>>> the 1st patch, how exactly read_tsc() looks like is orthogonal to
>>> the changes here at least as long as it doesn't live in .text.
>> Ok.  Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> 
> Actually, you probably want to move plt_src into __ro_after_init along
> with this change.

I'd view this as an independent change. Perhaps it would make for a
better change if we went through and converted from __read_mostly for
a bunch of items all in one go.

Jan