From f3c45326ee71d1d3ec11e9ddb5afc04bca9ae492 Mon Sep 17 00:00:00 2001 From: Joe Stringer Date: Sat, 10 Apr 2021 10:45:48 -0700 Subject: [PATCH] bpf: Document PROG_TEST_RUN limitations Per net/bpf/test_run.c, particular prog types have additional restrictions around the parameters that can be provided, so document these in the header. I didn't bother documenting the limitation on duration for raw tracepoints since that's an output parameter anyway. Tested with ./tools/testing/selftests/bpf/test_doc_build.sh. Suggested-by: Yonghong Song Signed-off-by: Joe Stringer Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Acked-by: Lorenz Bauer Link: https://lore.kernel.org/bpf/20210410174549.816482-1-joe@cilium.io --- include/uapi/linux/bpf.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 49371eba98ba..e1ee1be7e49b 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -312,6 +312,27 @@ union bpf_iter_link_info { * *ctx_out*, *data_out* (for example, packet data), result of the * execution *retval*, and *duration* of the test run. * + * The sizes of the buffers provided as input and output + * parameters *ctx_in*, *ctx_out*, *data_in*, and *data_out* must + * be provided in the corresponding variables *ctx_size_in*, + * *ctx_size_out*, *data_size_in*, and/or *data_size_out*. If any + * of these parameters are not provided (ie set to NULL), the + * corresponding size field must be zero. + * + * Some program types have particular requirements: + * + * **BPF_PROG_TYPE_SK_LOOKUP** + * *data_in* and *data_out* must be NULL. + * + * **BPF_PROG_TYPE_XDP** + * *ctx_in* and *ctx_out* must be NULL. + * + * **BPF_PROG_TYPE_RAW_TRACEPOINT**, + * **BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE** + * + * *ctx_out*, *data_in* and *data_out* must be NULL. + * *repeat* must be zero. + * * Return * Returns zero on success. On error, -1 is returned and *errno* * is set appropriately.