On 10/17/25 10:09, Nicola Vetrini wrote:
> On 2025-10-15 08:20, Jan Beulich wrote:
>> On 14.10.2025 18:16, Dmytro Prokopchuk1 wrote:
>>> --- a/xen/common/version.c
>>> +++ b/xen/common/version.c
>>> @@ -217,6 +217,20 @@ void __init xen_build_init(void)
>>> #endif /* CONFIG_X86 */
>>> }
>>> #endif /* BUILD_ID */
>>> +
>>> +#if defined(__i386__) || defined(__x86_64__) || defined(__arm__) ||
>>> defined(__aarch64__)
>>
>> Why __i386__? Also (nit): Line too long.
Well, I copied this line from Xen codebase,
but yeah, __i386__ is outdated now.
I'll remove it.
>>
>> And why this restriction without any comment here or ...
>>
>>> +static void __init __maybe_unused build_assertions(void)
>>> +{
>>> + /*
>>> + * To confirm conversion compatibility between unsigned long,
>>> (void *)
>>> + * and function pointers for X86 and ARM architectures only.
>>
>> ... explanation here? More generally - how would people know to update
>> the condition if another port was to be certified?
>>
>> Finally, with the v3 addition here, is Nicola's R-b really still
>> applicable?
>>
>
> I agree with the point you make about i386 (e.g., C-language-
> toolchain.rst may be mentioned to provide some context about the
> preprocessor guard); that said, my R-by can be retained
>
>> Jan
>>
>>> + */
>>> +
>>> + BUILD_BUG_ON(sizeof(unsigned long) != sizeof(void (*)(void)));
>>> + BUILD_BUG_ON(sizeof(void *) != sizeof(void (*)(void)));
>>> +}
>>> +#endif
>>> +
>>> /*
>>> * Local variables:
>>> * mode: C
>
And probably v4 can have the following wording:
/*
* This assertion checks compatibility between 'unsigned long', 'void *',
* and function pointers. This is true for X86 (x86_64) and ARM (arm,
aarch64)
* architectures, which is why the check is restricted to these.
*
* For more context on architecture-specific preprocessor guards, see
* docs/misc/C-language-toolchain.rst.
*
* If Xen is ported to a new architecture, verify that this
compatibility holds
* before adding its macro to the condition below. If the compatibility
does not
* hold, this assertion may need to be revised or removed for that
architecture.
*/
BR, Dmytro.
