selftest/bpf: Add relocatable bitfield reading tests

Add a bunch of selftests verifying correctness of relocatable bitfield reading
support in libbpf. Both bpf_probe_read()-based and direct read-based bitfield
macros are tested. core_reloc.c "test_harness" is extended to support raw
tracepoint and new typed raw tracepoints as test BPF program types.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191101222810.1246166-5-andriin@fb.com

1 files changed, 62 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_probed.c b/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_probed.c
new file mode 100644
index 000000000000..a381f8ac2419
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_bitfields_probed.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+
+#include <linux/bpf.h>
+#include <stdint.h>
+#include "bpf_helpers.h"
+#include "bpf_core_read.h"
+
+char _license[] SEC("license") = "GPL";
+
+static volatile struct data {
+	char in[256];
+	char out[256];
+} data;
+
+struct core_reloc_bitfields {
+	/* unsigned bitfields */
+	uint8_t		ub1: 1;
+	uint8_t		ub2: 2;
+	uint32_t	ub7: 7;
+	/* signed bitfields */
+	int8_t		sb4: 4;
+	int32_t		sb20: 20;
+	/* non-bitfields */
+	uint32_t	u32;
+	int32_t		s32;
+};
+
+/* bitfield read results, all as plain integers */
+struct core_reloc_bitfields_output {
+	int64_t		ub1;
+	int64_t		ub2;
+	int64_t		ub7;
+	int64_t		sb4;
+	int64_t		sb20;
+	int64_t		u32;
+	int64_t		s32;
+};
+
+#define TRANSFER_BITFIELD(in, out, field)				\
+	if (BPF_CORE_READ_BITFIELD_PROBED(in, field, &res))		\
+		return 1;						\
+	out->field = res
+
+SEC("raw_tracepoint/sys_enter")
+int test_core_bitfields(void *ctx)
+{
+	struct core_reloc_bitfields *in = (void *)&data.in;
+	struct core_reloc_bitfields_output *out = (void *)&data.out;
+	uint64_t res;
+
+	TRANSFER_BITFIELD(in, out, ub1);
+	TRANSFER_BITFIELD(in, out, ub2);
+	TRANSFER_BITFIELD(in, out, ub7);
+	TRANSFER_BITFIELD(in, out, sb4);
+	TRANSFER_BITFIELD(in, out, sb20);
+	TRANSFER_BITFIELD(in, out, u32);
+	TRANSFER_BITFIELD(in, out, s32);
+
+	return 0;
+}
+