Re: [PATCH V2] selftests/sgx: Fix build error caused by missing dependency

[Shuah Khan <skhan@linuxfoundation.org>]

On 12/14/21 3:27 PM, Reinette Chatre wrote:
> Hi Shuah,
> 
> On 12/14/2021 1:55 PM, Shuah Khan wrote:
>> On 12/14/21 2:28 PM, Reinette Chatre wrote:
>>> Hi Shuah,
>>>
>>> On 12/14/2021 12:10 PM, Shuah Khan wrote:
>>>
>>>>
>>>> Let's not add one more __cpuid() define to the individual tests.
>>>> We so far have:
>>>>
>>>> tools/testing/selftests/vm/pkey-x86.h
>>>> selftests/x86/corrupt_xstate_header.c
>>>>
>>>> Let's move the defines to kselftest.h and remove all these duplicate
>>>> defines.
>>>>
>>>> For now you could include vm/pkey-x86.h just to fix the build error
>>>> and do the proper cleanup.
>>>
>>> Thank you so much for taking a look. We actually do have an alternative fix that could be considered for the other users of __cpuid(). Instead of another clone of the kernel's __cpuid() the fix includes cpuid.h and uses the existing __cpuid_count() from it.
>>>
>>> Please see:
>>> https://lore.kernel.org/linux-sgx/20211204202355.23005-1-jarkko@kernel.org/
>>>
>>
>> This looks good to me.
> 
> Thank you very much for taking a look.
> 
>>
>>> We decided against the above fix using __cpuid_count() because we could not explain why all the existing users of __cpuid() implement their own and decided to follow the custom instead ...
>>>
>>
>> Most likely, copy and paste and taking the easy route. I looked at a couple of
>> defines and I dont't see a difference. If there are differences, that would be
>> a bigger concern. The whole idea of not having duplicates is that we don't have
>> bugs in these duplicates.
>>
>>> Do you see any problem with including cpuid.h into a selftest? If not, then we can go back to our original fix of this issue and I could also submit a change to remove all the __cpuid() clones and replace them with the library's __cpuid_count().
>>>
>>
>> There are no problems including cpuid.h - where is this though. I couldn't find
>> it in my cscope search?
> 
> On my system it arrived via user space's libgcc-dev package. This does not seem to be the first time including files from this source - I did a quick check and from what I can tell existing includes like stdarg.h, stdbool.h, stdatomic.h, unwind.h, x86intrin.h ... arrive via libgcc-dev.
> 
> Do you still find that cpuid.h is ok to include?
> 
> Reinette

Yes. I found it on my system as well.

/usr/lib/llvm-13/lib/clang/13.0.0/include/cpuid.h
/usr/lib/llvm-12/lib/clang/12.0.1/include/cpuid.h
/usr/lib/gcc/x86_64-linux-gnu/11/include/cpuid.h
/usr/lib/gcc/x86_64-linux-gnu/10/include/cpuid.h

No problems using it.

thanks,
-- Shuah