selftests/bpf: add CO-RE relocs array tests

Add tests for various array handling/relocation scenarios.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/prog_tests/core_reloc.c

@@ -51,6 +51,36 @@
 	.fails = true,							\
 }
 
+#define ARRAYS_DATA(struct_name) STRUCT_TO_CHAR_PTR(struct_name) {	\
+	.a = { [2] = 1 },						\
+	.b = { [1] = { [2] = { [3] = 2 } } },				\
+	.c = { [1] = { .c =  3 } },					\
+	.d = { [0] = { [0] = { .d = 4 } } },				\
+}
+
+#define ARRAYS_CASE_COMMON(name)					\
+	.case_name = #name,						\
+	.bpf_obj_file = "test_core_reloc_arrays.o",			\
+	.btf_src_file = "btf__core_reloc_" #name ".o"
+
+#define ARRAYS_CASE(name) {						\
+	ARRAYS_CASE_COMMON(name),					\
+	.input = ARRAYS_DATA(core_reloc_##name),			\
+	.input_len = sizeof(struct core_reloc_##name),			\
+	.output = STRUCT_TO_CHAR_PTR(core_reloc_arrays_output) {	\
+		.a2   = 1,						\
+		.b123 = 2,						\
+		.c1c  = 3,						\
+		.d00d = 4,						\
+	},								\
+	.output_len = sizeof(struct core_reloc_arrays_output)		\
+}
+
+#define ARRAYS_ERR_CASE(name) {						\
+	ARRAYS_CASE_COMMON(name),					\
+	.fails = true,							\
+}
+
 struct core_reloc_test_case {
 	const char *case_name;
 	const char *bpf_obj_file;
@@ -96,6 +126,17 @@ static struct core_reloc_test_case test_cases[] = {
 	NESTING_ERR_CASE(nesting___err_dup_incompat_types),
 	NESTING_ERR_CASE(nesting___err_partial_match_dups),
 	NESTING_ERR_CASE(nesting___err_too_deep),
+
+	/* various array access relocation scenarios */
+	ARRAYS_CASE(arrays),
+	ARRAYS_CASE(arrays___diff_arr_dim),
+	ARRAYS_CASE(arrays___diff_arr_val_sz),
+
+	ARRAYS_ERR_CASE(arrays___err_too_small),
+	ARRAYS_ERR_CASE(arrays___err_too_shallow),
+	ARRAYS_ERR_CASE(arrays___err_non_array),
+	ARRAYS_ERR_CASE(arrays___err_wrong_val_type1),
+	ARRAYS_ERR_CASE(arrays___err_wrong_val_type2),
 };
 
 struct data {

tools/testing/selftests/bpf/progs/btf__core_reloc_arrays.c

+#include "core_reloc_types.h"
+
+void f(struct core_reloc_arrays x) {}

tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___diff_arr_dim.c

+#include "core_reloc_types.h"
+
+void f(struct core_reloc_arrays___diff_arr_dim x) {}

tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___diff_arr_val_sz.c

+#include "core_reloc_types.h"
+
+void f(struct core_reloc_arrays___diff_arr_val_sz x) {}

tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___err_non_array.c

+#include "core_reloc_types.h"
+
+void f(struct core_reloc_arrays___err_non_array x) {}

tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___err_too_shallow.c

+#include "core_reloc_types.h"
+
+void f(struct core_reloc_arrays___err_too_shallow x) {}

tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___err_too_small.c

+#include "core_reloc_types.h"
+
+void f(struct core_reloc_arrays___err_too_small x) {}

tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___err_wrong_val_type1.c

+#include "core_reloc_types.h"
+
+void f(struct core_reloc_arrays___err_wrong_val_type1 x) {}

tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___err_wrong_val_type2.c

+#include "core_reloc_types.h"
+
+void f(struct core_reloc_arrays___err_wrong_val_type2 x) {}

tools/testing/selftests/bpf/progs/core_reloc_types.h

@@ -306,3 +306,84 @@ struct core_reloc_nesting___err_too_deep {
 		} b;
 	} b;
 };
+
+/*
+ * ARRAYS
+ */
+struct core_reloc_arrays_output {
+	int a2;
+	char b123;
+	int c1c;
+	int d00d;
+};
+
+struct core_reloc_arrays_substruct {
+	int c;
+	int d;
+};
+
+struct core_reloc_arrays {
+	int a[5];
+	char b[2][3][4];
+	struct core_reloc_arrays_substruct c[3];
+	struct core_reloc_arrays_substruct d[1][2];
+};
+
+/* bigger array dimensions */
+struct core_reloc_arrays___diff_arr_dim {
+	int a[7];
+	char b[3][4][5];
+	struct core_reloc_arrays_substruct c[4];
+	struct core_reloc_arrays_substruct d[2][3];
+};
+
+/* different size of array's value (struct) */
+struct core_reloc_arrays___diff_arr_val_sz {
+	int a[5];
+	char b[2][3][4];
+	struct {
+		int __padding1;
+		int c;
+		int __padding2;
+	} c[3];
+	struct {
+		int __padding1;
+		int d;
+		int __padding2;
+	} d[1][2];
+};
+
+struct core_reloc_arrays___err_too_small {
+	int a[2]; /* this one is too small */
+	char b[2][3][4];
+	struct core_reloc_arrays_substruct c[3];
+	struct core_reloc_arrays_substruct d[1][2];
+};
+
+struct core_reloc_arrays___err_too_shallow {
+	int a[5];
+	char b[2][3]; /* this one lacks one dimension */
+	struct core_reloc_arrays_substruct c[3];
+	struct core_reloc_arrays_substruct d[1][2];
+};
+
+struct core_reloc_arrays___err_non_array {
+	int a; /* not an array */
+	char b[2][3][4];
+	struct core_reloc_arrays_substruct c[3];
+	struct core_reloc_arrays_substruct d[1][2];
+};
+
+struct core_reloc_arrays___err_wrong_val_type1 {
+	char a[5]; /* char instead of int */
+	char b[2][3][4];
+	struct core_reloc_arrays_substruct c[3];
+	struct core_reloc_arrays_substruct d[1][2];
+};
+
+struct core_reloc_arrays___err_wrong_val_type2 {
+	int a[5];
+	char b[2][3][4];
+	int c[3]; /* value is not a struct */
+	struct core_reloc_arrays_substruct d[1][2];
+};

tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Facebook
+
+#include <linux/bpf.h>
+#include <stdint.h>
+#include "bpf_helpers.h"
+
+char _license[] SEC("license") = "GPL";
+
+static volatile struct data {
+	char in[256];
+	char out[256];
+} data;
+
+struct core_reloc_arrays_output {
+	int a2;
+	char b123;
+	int c1c;
+	int d00d;
+};
+
+struct core_reloc_arrays_substruct {
+	int c;
+	int d;
+};
+
+struct core_reloc_arrays {
+	int a[5];
+	char b[2][3][4];
+	struct core_reloc_arrays_substruct c[3];
+	struct core_reloc_arrays_substruct d[1][2];
+};
+
+SEC("raw_tracepoint/sys_enter")
+int test_core_arrays(void *ctx)
+{
+	struct core_reloc_arrays *in = (void *)&data.in;
+	struct core_reloc_arrays_output *out = (void *)&data.out;
+
+	/* in->a[2] */
+	if (BPF_CORE_READ(&out->a2, &in->a[2]))
+		return 1;
+	/* in->b[1][2][3] */
+	if (BPF_CORE_READ(&out->b123, &in->b[1][2][3]))
+		return 1;
+	/* in->c[1].c */
+	if (BPF_CORE_READ(&out->c1c, &in->c[1].c))
+		return 1;
+	/* in->d[0][0].d */
+	if (BPF_CORE_READ(&out->d00d, &in->d[0][0].d))
+		return 1;
+
+	return 0;
+}
+