Re: next-20250909: selftests/arm64/gcs/basic-gcs.c:390:30: error: use of undeclared identifier 'HWCAP_GCS'

["Thomas Weißschuh" <linux@weissschuh.net>]

Sep 12, 2025 12:57:15 Thomas Weißschuh <linux@weissschuh.net>:

> Sep 12, 2025 12:49:58 Mark Brown <broonie@kernel.org>:
>
>> On Fri, Sep 12, 2025 at 08:30:08AM +0200, Thomas Weißschuh wrote:
>>> On 2025-09-12 00:48:47+0530, Naresh Kamboju wrote:
>>
>>> index c99a6b39ac14..816b497634d6 100644
>>> --- a/tools/testing/selftests/arm64/gcs/gcs-util.h
>>> +++ b/tools/testing/selftests/arm64/gcs/gcs-util.h
>>> @@ -26,6 +26,10 @@ struct user_gcs {
>>> };
>>> #endif
>>>
>>> +#ifndef HWCAP_GCS
>>> +#define HWCAP_GCS (1UL << 32)
>>> +#endif
>>> +
>>
>> We're doing that for glibc using tests because there's some unfortunate
>> interaction between including the relevant kernel header and glibc's
>> headers (I forget the details) which means that including the kernel
>> header directly conflicts with something glibc is doing.  For nolibc I
>> would expect us to using the kernel's hwcap definitions?
>
> nolibc doesn't even have its own asm/hwcap.h (or any asm/ header for that matter).
> So a kernel header has to be used,
> maybe an old one is pulled from somewhere?


The Makefile does *not* use -nostdinc, so the nolibc program probably finds the toolchain's glibc asm/hwcap.h.
There also doesn't seem to be a static arm64 hwcap header in tools/include in the first place.
I am still wondering how this works for the other tests.


Thomas