On Thu, Apr 11, 2024 at 9:11 PM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> Three new kfuncs, namely bpf_iter_bits_{new,next,destroy}, have been
> added for the new bpf_iter_bits functionality. These kfuncs enable the
> iteration of the bits from a given address and a given number of bits.
>
> - bpf_iter_bits_new
> Initialize a new bits iterator for a given memory area. Due to the
> limitation of bpf memalloc, the max number of bits to be iterated
> over is (4096 * 8).
> - bpf_iter_bits_next
> Get the next bit in a bpf_iter_bits
> - bpf_iter_bits_destroy
> Destroy a bpf_iter_bits
>
> The bits iterator can be used in any context and on any address.
>
> Changes:
> - v5->v6:
> - Add positive tests (Andrii)
> - v4->v5:
> - Simplify test cases (Andrii)
> - v3->v4:
> - Fix endianness error on s390x (Andrii)
> - zero-initialize kit->bits_copy and zero out nr_bits (Andrii)
> - v2->v3:
> - Optimization for u64/u32 mask (Andrii)
> - v1->v2:
> - Simplify the CPU number verification code to avoid the failure on s390x
> (Eduard)
> - bpf: Add bpf_iter_cpumask
> https://lwn.net/Articles/961104/
> - bpf: Add new bpf helper bpf_for_each_cpu
> https://lwn.net/Articles/939939/
>
> Yafang Shao (2):
> bpf: Add bits iterator
> selftests/bpf: Add selftest for bits iter
>
> kernel/bpf/helpers.c | 120 +++++++++++++++++
> .../selftests/bpf/prog_tests/verifier.c | 2 +
> .../selftests/bpf/progs/verifier_bits_iter.c | 127 ++++++++++++++++++
> 3 files changed, 249 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/verifier_bits_iter.c
>
> --
> 2.39.1
>
It appears that the test case failed on s390x when the data is
a u32 value because we need to set the higher 32 bits.
will analyze it.
--
Regards
Yafang
