[PATCH v2 5/6] powerpc/64: Add support for out-of-line static calls

[Christophe Leroy]

Le 27/09/2022 à 05:21, Benjamin Gray a écrit :
> On Mon, 2022-09-26 at 14:54 +0000, Christophe Leroy wrote:
>>> diff --git a/arch/powerpc/kernel/static_call.c
>>> b/arch/powerpc/kernel/static_call.c
>>> index 863a7aa24650..ecbb74e1b4d3 100644
>>> --- a/arch/powerpc/kernel/static_call.c
>>> +++ b/arch/powerpc/kernel/static_call.c
>>> @@ -4,30 +4,108 @@
>>>    
>>>    #include <asm/code-patching.h>
>>>    
>>> +static void* ppc_function_toc(u32 *func)
>>> +{
>>> +#ifdef CONFIG_PPC64_ELF_ABI_V2
>>
>> Can you use IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) instead ?
> 
> I tried when implementing it, but the `(u64) func` cast is an issue. I
> could side step it and use `unsigned long` if that's preferable?
> Otherwise I like being explicit about the size, it's a delicate
> function.

It is always better to have code that builds independant of config 
options. I helps with build converage, you don't have to build thousands 
of defconfigs in order to cover all options.

See 
https://docs.kernel.org/process/coding-style.html#conditional-compilation

For me, using "unsigned long" is more explicit than u64 when it 
represents the value of a pointer.