Re: [PATCH v2 2/2] xen: Populate xen.lds.h and make use of its macros

[Michal Orzel <michal.orzel@xxxxxxx>]

On 30.03.2022 14:53, Jan Beulich wrote:
> On 30.03.2022 14:13, Michal Orzel wrote:
>> On 30.03.2022 13:57, Jan Beulich wrote:
>>> On 30.03.2022 13:04, Michal Orzel wrote:
>>>> On 30.03.2022 12:42, Jan Beulich wrote:
>>>>> On 30.03.2022 12:32, Julien Grall wrote:
>>>>>> Renaming to PE_COFF may help to avoid the confusion with CONFIG_EFI. 
>>>>>> That said, it would possibly make more difficult to associate the flag 
>>>>>> with "linking an EFI binary".
>>>>>
>>>>> Indeed. And EFI_PE_COFF is getting a little unwieldy for my taste.
>>>>>
>>>>>> I think some documentaion about the define EFI would be help so there 
>>>>>> are no more confusion between CONFIG_EFI/EFI. But I am not sure where to 
>>>>>> put it. Maybe at the top of the header?
>>>>>
>>>>> That's perhaps the best place, yes.
>>>>>
>>>> In this case how about the following comment at the top of xen.lds.h:
>>>>
>>>> "To avoid any confusion about EFI macro used in this header vs EFI support,
>>>> the former is used when linking a native EFI (i.e. PE/COFF) binary, whereas
>>>> the latter means support for generating EFI binary.
>>>
>>> No, that's the case on Arm only. As Julien suggested, it is perhaps best
>>> to explain the difference between EFI and CONFIG_EFI, without going into
>>> arch specifics.
>> Could you please tell me what you are reffering to as there is no such 
>> identifier
>> in Xen (as opposed to Linux) like CONFIG_EFI ?
> 
> Let's call it a "virtual" CONFIG_EFI then; I think we really should have
> such an option. But yes, if you don't like referring to such a virtual
> option, then describing what is meant verbally is certainly going to be
> fine.
> 
FWICS, there was an attempt done by Wei in his NUMA series to define CONFIG_EFI.
However as this is not yet merged and agreed, I would like not to refer to 
identifiers
not existing in the code, even though most people are familiar with this option 
from Linux.

So by taking an example from Linux I would verbally explain it like that:
"To avoid any confusion, please note that EFI macro does not correspond to EFI
runtime support and is used when linking a native EFI (i.e. PE/COFF) binary, 
hence its
usage in this header."

If that does not suite you, please help creating a better explanation.

> Jan
> 

Michal