selftests/bpf: Test for btf_load command.

Improve selftest to check that btf_load is working from bpf program.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210514003623.28033-8-alexei.starovoitov@gmail.com

diff --git a/tools/testing/selftests/bpf/prog_tests/syscall.c b/tools/testing/selftests/bpf/prog_tests/syscall.c
index 1badd37148a10e5a025804a9c7f6919d866e818b..81e997a69f7ae1d9bd5b5e7e91c94612691b9750 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/syscall.c
@@ -9,6 +9,7 @@ struct args {
        int max_entries;
        int map_fd;
        int prog_fd;
+       int btf_fd;
 };
 
 void test_syscall(void)
@@ -49,4 +50,6 @@ cleanup:
                close(ctx.prog_fd);
        if (ctx.map_fd > 0)
                close(ctx.map_fd);
+       if (ctx.btf_fd > 0)
+               close(ctx.btf_fd);
 }

diff --git a/tools/testing/selftests/bpf/progs/syscall.c b/tools/testing/selftests/bpf/progs/syscall.c
index 865b5269ecbb04ab7b56d0eebf6946559495a387..e550f728962d402c29a6f26312be271cd84c62bb 100644 (file)
--- a/tools/testing/selftests/bpf/progs/syscall.c
+++ b/tools/testing/selftests/bpf/progs/syscall.c
@@ -5,6 +5,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 #include <../../../tools/include/linux/filter.h>
+#include <linux/btf.h>
 
 char _license[] SEC("license") = "GPL";
 
@@ -14,8 +15,48 @@ struct args {
        int max_entries;
        int map_fd;
        int prog_fd;
+       int btf_fd;
 };
 
+#define BTF_INFO_ENC(kind, kind_flag, vlen) \
+       ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
+#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
+#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
+       ((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
+#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
+       BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
+       BTF_INT_ENC(encoding, bits_offset, bits)
+
+static int btf_load(void)
+{
+       struct btf_blob {
+               struct btf_header btf_hdr;
+               __u32 types[8];
+               __u32 str;
+       } raw_btf = {
+               .btf_hdr = {
+                       .magic = BTF_MAGIC,
+                       .version = BTF_VERSION,
+                       .hdr_len = sizeof(struct btf_header),
+                       .type_len = sizeof(__u32) * 8,
+                       .str_off = sizeof(__u32) * 8,
+                       .str_len = sizeof(__u32),
+               },
+               .types = {
+                       /* long */
+                       BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 64, 8),  /* [1] */
+                       /* unsigned long */
+                       BTF_TYPE_INT_ENC(0, 0, 0, 64, 8),  /* [2] */
+               },
+       };
+       static union bpf_attr btf_load_attr = {
+               .btf_size = sizeof(raw_btf),
+       };
+
+       btf_load_attr.btf = (long)&raw_btf;
+       return bpf_sys_bpf(BPF_BTF_LOAD, &btf_load_attr, sizeof(btf_load_attr));
+}
+
 SEC("syscall")
 int bpf_prog(struct args *ctx)
 {
@@ -33,6 +74,8 @@ int bpf_prog(struct args *ctx)
                .map_type = BPF_MAP_TYPE_HASH,
                .key_size = 8,
                .value_size = 8,
+               .btf_key_type_id = 1,
+               .btf_value_type_id = 2,
        };
        static union bpf_attr map_update_attr = { .map_fd = 1, };
        static __u64 key = 12;
@@ -43,7 +86,14 @@ int bpf_prog(struct args *ctx)
        };
        int ret;
 
+       ret = btf_load();
+       if (ret <= 0)
+               return ret;
+
+       ctx->btf_fd = ret;
        map_create_attr.max_entries = ctx->max_entries;
+       map_create_attr.btf_fd = ret;
+
        prog_load_attr.license = (long) license;
        prog_load_attr.insns = (long) insns;
        prog_load_attr.log_buf = ctx->log_buf;