On Wed, Mar 31, 2021 at 9:45 AM Yauheni Kaliuta
<yauheni.kaliuta@xxxxxxxxxx> wrote:
>
> Since there is no convenient way for bpf program to get PAGE_SIZE
> from inside of the kernel, pass the value from userspace.
>
> Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx>
> ---
> tools/testing/selftests/bpf/prog_tests/sockopt_sk.c | 2 ++
> tools/testing/selftests/bpf/progs/sockopt_sk.c | 10 ++++------
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c b/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
> index 7274b12abe17..4b937e5dbaca 100644
> --- a/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
> +++ b/tools/testing/selftests/bpf/prog_tests/sockopt_sk.c
> @@ -200,6 +200,8 @@ static void run_test(int cgroup_fd)
> if (!ASSERT_OK_PTR(skel, "skel_load"))
> goto cleanup;
>
> + skel->bss->page_size = getpagesize();
> +
> skel->links._setsockopt =
> bpf_program__attach_cgroup(skel->progs._setsockopt, cgroup_fd);
> if (!ASSERT_OK_PTR(skel->links._setsockopt, "setsockopt_link"))
> diff --git a/tools/testing/selftests/bpf/progs/sockopt_sk.c b/tools/testing/selftests/bpf/progs/sockopt_sk.c
> index 978a68005966..d6d03f64e2e4 100644
> --- a/tools/testing/selftests/bpf/progs/sockopt_sk.c
> +++ b/tools/testing/selftests/bpf/progs/sockopt_sk.c
> @@ -7,9 +7,7 @@
>
> char _license[] SEC("license") = "GPL";
>
> -#ifndef PAGE_SIZE
> -#define PAGE_SIZE 4096
> -#endif
> +int page_size; /* userspace should set it */
please zero-initialize this, otherwise it will cause problems on some
versions of Clang
>
> #ifndef SOL_TCP
> #define SOL_TCP IPPROTO_TCP
> @@ -89,7 +87,7 @@ int _getsockopt(struct bpf_sockopt *ctx)
> * program can only see the first PAGE_SIZE
> * bytes of data.
> */
> - if (optval_end - optval != PAGE_SIZE)
> + if (optval_end - optval != page_size)
> return 0; /* EPERM, unexpected data size */
>
> return 1;
> @@ -160,7 +158,7 @@ int _setsockopt(struct bpf_sockopt *ctx)
>
> if (ctx->level == SOL_IP && ctx->optname == IP_FREEBIND) {
> /* Original optlen is larger than PAGE_SIZE. */
> - if (ctx->optlen != PAGE_SIZE * 2)
> + if (ctx->optlen != page_size * 2)
> return 0; /* EPERM, unexpected data size */
>
> if (optval + 1 > optval_end)
> @@ -174,7 +172,7 @@ int _setsockopt(struct bpf_sockopt *ctx)
> * program can only see the first PAGE_SIZE
> * bytes of data.
> */
> - if (optval_end - optval != PAGE_SIZE)
> + if (optval_end - optval != page_size)
> return 0; /* EPERM, unexpected data size */
>
> return 1;
> --
> 2.31.1
>
