selftests/bpf: Add field size relocation tests

Add test verifying correctness and logic of field size relocation support in
libbpf.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191101222810.1246166-6-andriin@fb.com

4 files changed, 88 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/btf__core_reloc_size.c b/tools/testing/selftests/bpf/progs/btf__core_reloc_size.c
new file mode 100644
index 000000000000..3c80903da5a4
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/btf__core_reloc_size.c
@@ -0,0 +1,3 @@
+#include "core_reloc_types.h"
+
+void f(struct core_reloc_size x) {}
diff --git a/tools/testing/selftests/bpf/progs/btf__core_reloc_size___diff_sz.c b/tools/testing/selftests/bpf/progs/btf__core_reloc_size___diff_sz.c
new file mode 100644
index 000000000000..6dbd14436b52
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/btf__core_reloc_size___diff_sz.c
@@ -0,0 +1,3 @@
+#include "core_reloc_types.h"
+
+void f(struct core_reloc_size___diff_sz x) {}
diff --git a/tools/testing/selftests/bpf/progs/core_reloc_types.h b/tools/testing/selftests/bpf/progs/core_reloc_types.h
index 7eb08d99ec46..9311489e14b2 100644
--- a/tools/testing/selftests/bpf/progs/core_reloc_types.h
+++ b/tools/testing/selftests/bpf/progs/core_reloc_types.h
@@ -734,3 +734,34 @@ struct core_reloc_bitfields___err_too_big_bitfield {
 	uint32_t	u32;
 	uint32_t	s32;
 } __attribute__((packed)) ;
+
+/*
+ * SIZE
+ */
+struct core_reloc_size_output {
+	int int_sz;
+	int struct_sz;
+	int union_sz;
+	int arr_sz;
+	int arr_elem_sz;
+	int ptr_sz;
+	int enum_sz;
+};
+
+struct core_reloc_size {
+	int int_field;
+	struct { int x; } struct_field;
+	union { int x; } union_field;
+	int arr_field[4];
+	void *ptr_field;
+	enum { VALUE = 123 } enum_field;
+};
+
+struct core_reloc_size___diff_sz {
+	uint64_t int_field;
+	struct { int x; int y; int z; } struct_field;
+	union { int x; char bla[123]; } union_field;
+	char arr_field[10];
+	void *ptr_field;
+	enum { OTHER_VALUE = 0xFFFFFFFFFFFFFFFF } enum_field;
+};
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_size.c b/tools/testing/selftests/bpf/progs/test_core_reloc_size.c
new file mode 100644
index 000000000000..9a92998d9107
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_size.c
@@ -0,0 +1,51 @@
+// 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_size_output {
+	int int_sz;
+	int struct_sz;
+	int union_sz;
+	int arr_sz;
+	int arr_elem_sz;
+	int ptr_sz;
+	int enum_sz;
+};
+
+struct core_reloc_size {
+	int int_field;
+	struct { int x; } struct_field;
+	union { int x; } union_field;
+	int arr_field[4];
+	void *ptr_field;
+	enum { VALUE = 123 } enum_field;
+};
+
+SEC("raw_tracepoint/sys_enter")
+int test_core_size(void *ctx)
+{
+	struct core_reloc_size *in = (void *)&data.in;
+	struct core_reloc_size_output *out = (void *)&data.out;
+
+	out->int_sz = bpf_core_field_size(in->int_field);
+	out->struct_sz = bpf_core_field_size(in->struct_field);
+	out->union_sz = bpf_core_field_size(in->union_field);
+	out->arr_sz = bpf_core_field_size(in->arr_field);
+	out->arr_elem_sz = bpf_core_field_size(in->arr_field[0]);
+	out->ptr_sz = bpf_core_field_size(in->ptr_field);
+	out->enum_sz = bpf_core_field_size(in->enum_field);
+
+	return 0;
+}
+