Eelco Chaudron wrote:
> Introduce new helper that reuses existing xdp perf_event output
> implementation, but can be called from raw_tracepoint programs
> that receive 'struct xdp_buff *' as a tracepoint argument.
>
> Signed-off-by: Eelco Chaudron <echaudro@xxxxxxxxxx>
> ---
> include/uapi/linux/bpf.h | 27 ++++++++++
> kernel/bpf/verifier.c | 4 +-
> kernel/trace/bpf_trace.c | 3 +
> net/core/filter.c | 16 ++++++
> tools/include/uapi/linux/bpf.h | 27 ++++++++++
> .../testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c | 53 ++++++++++++++++++++
> .../testing/selftests/bpf/progs/test_xdp_bpf2bpf.c | 24 +++++++++
> 7 files changed, 150 insertions(+), 4 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 40b2d9476268..41a90e2d5821 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -2914,6 +2914,30 @@ union bpf_attr {
> * of sizeof(struct perf_branch_entry).
> *
> * **-ENOENT** if architecture does not support branch records.
> + *
> + * int bpf_xdp_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
> + * Description
feels a bit odd to have flags in the middle of a signature but it follows
bpf_perf_event_output() so I guess its better to have the two use the
same signature vs break it here.
> + * Write raw *data* blob into a special BPF perf event held by
> + * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
> + * event must have the following attributes: **PERF_SAMPLE_RAW**
> + * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
> + * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
> + *
> + * The *flags* are used to indicate the index in *map* for which
> + * the value must be put, masked with **BPF_F_INDEX_MASK**.
> + * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
> + * to indicate that the index of the current CPU core should be
> + * used.
> + *
> + * The value to write, of *size*, is passed through eBPF stack and
> + * pointed by *data*.
> + *
> + * *ctx* is a pointer to in-kernel struct xdp_buff.
> + *
> + * This helper is similar to **bpf_perf_eventoutput**\ () but
> + * restricted to raw_tracepoint bpf programs.
> + * Return
> + * 0 on success, or a negative error in case of failure.
> */
Otherwise,
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
