Re: [PATCH 1/2] xen/dom0less: mark domain_p2m_set_allocation __init

[Jan Beulich <jbeulich@xxxxxxxx>]

On 14.05.2025 09:04, Orzel, Michal wrote:
> On 14/05/2025 08:56, Jan Beulich wrote:
>> On 14.05.2025 08:31, Orzel, Michal wrote:
>>> On 14/05/2025 02:07, Stefano Stabellini wrote:
>>>> On Tue, 13 May 2025, Stewart Hildebrand wrote:
>>>>> All functions in dom0less-build.c should be __init.
>>> Why? This patch is first in your series and by that time there is no build 
>>> time
>>> enforcement. Together with the Fixes tag it implies that this is somehow an
>>> issue (i.e. build/runtime issue) other than inconsistency for which we 
>>> surely
>>> don't need Fixes tag.
>>
>> I disagree: Code not called post-init should be in .init.*. While not 
>> formally
>> a Misra violation (and wrongly so, I think), it imo effectively is: Such code
>> is otherwise unreachable post-init.
> You have a point here, I agree. Although I don't think MISRA differentiates
> between unreachable in general vs pre or post init. It defines it as code that
> cannot be executed. It does not go into stages of runtime execution.

Right, hence how I wrote my earlier reply. Elsewhere, however, Misra (or at
least our interpretation of it) does appear to care about init vs runtime,
in e.g. desiring no runtime allocations.

> I'm thinking how this is different from a function that is called e.g. only 
> once
> at specific point at runtime execution for which we did not come up with a
> separate section?

With enough effort such could also be covered, I expect, yet at the same time 
the
ultimate result may be coming close to getting out of control. Whereas for init
vs post-init we already have a pretty clear boundary, with memory used merely 
for
init actually properly reclaimed.

Jan