Re: [PATCH bpf-next v1] selftests/bpf: Fix arena_spin_lock compilation on PowerPC

[Venkat Rao Bagalkote <venkat88@linux.ibm.com>]

On 11/03/25 9:13 pm, Kumar Kartikeya Dwivedi wrote:
> On Tue, 11 Mar 2025 at 16:42, Kumar Kartikeya Dwivedi <memxor@gmail.com> wrote:
>> Venkat reported a compilation error for BPF selftests on PowerPC [0].
>> The crux of the error is the following message:
>>    In file included from progs/arena_spin_lock.c:7:
>>    /root/bpf-next/tools/testing/selftests/bpf/bpf_arena_spin_lock.h:122:8:
>>    error: member reference base type '__attribute__((address_space(1)))
>>    u32' (aka '__attribute__((address_space(1))) unsigned int') is not a
>>    structure or union
>>       122 |         old = atomic_read(&lock->val);
>>
>> This is because PowerPC overrides the qspinlock type changing the
>> lock->val member's type from atomic_t to u32.
>>
>> To remedy this, import the asm-generic version in the arena spin lock
>> header, name it __qspinlock (since it's aliased to arena_spinlock_t, the
>> actual name hardly matters), and adjust the selftest to not depend on
>> the type in vmlinux.h.
>>
>>    [0]: https://lore.kernel.org/bpf/7bc80a3b-d708-4735-aa3b-6a8c21720f9d@linux.ibm.com
>>
>> Fixes: 0201027a026c ("selftests/bpf: Introduce arena spin lock")
>> Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
>> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
>> ---

Built the kernel by applying this patch on bpf-next. And selftests/bpf 
compiles successfully.

Please add below tag.


Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>

> Venkat, please help test, as CI and I don't have access to a PowerPC machine.
>
> Thanks!