[PATCH v2 bpf-next 05/12] selftests/bpf: add CO-RE relocs struct flavors tests

Andrii Nakryiko
2019-07-30T19:54:28Z

Add tests verifying that BPF program can use various struct/union
"flavors" to extract data from the same target struct/union.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
---
.../selftests/bpf/prog_tests/core_reloc.c | 34 ++++++++++
.../bpf/progs/btf__core_reloc_flavors.c | 3 +
.../btf__core_reloc_flavors__err_wrong_name.c | 3 +
.../selftests/bpf/progs/core_reloc_types.h | 15 +++++
.../bpf/progs/test_core_reloc_flavors.c | 62 +++++++++++++++++++
5 files changed, 117 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_flavors.c
create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_flavors__err_wrong_name.c
create mode 100644 tools/testing/selftests/bpf/progs/core_reloc_types.h
create mode 100644 tools/testing/selftests/bpf/progs/test_core_reloc_flavors.c

diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
index fab7492a8714..c147271deee6 100644
--- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
@@ -1,5 +1,32 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
+#include "progs/core_reloc_types.h"
+
+#define STRUCT_TO_CHAR_PTR(struct_name) (const char *)&(struct struct_name)
+
+#define FLAVORS_DATA(struct_name) STRUCT_TO_CHAR_PTR(struct_name) { \
+ .a = 42, \
+ .b = 0xc001, \
+ .c = 0xbeef, \
+}
+
+#define FLAVORS_CASE_COMMON(name) \
+ .case_name = #name, \
+ .bpf_obj_file = "test_core_reloc_flavors.o", \
+ .btf_src_file = "btf__core_reloc_" #name ".o" \
+
+#define FLAVORS_CASE(name) { \
+ FLAVORS_CASE_COMMON(name), \
+ .input = FLAVORS_DATA(core_reloc_##name), \
+ .input_len = sizeof(struct core_reloc_##name), \
+ .output = FLAVORS_DATA(core_reloc_flavors), \
+ .output_len = sizeof(struct core_reloc_flavors), \
+}
+
+#define FLAVORS_ERR_CASE(name) { \
+ FLAVORS_CASE_COMMON(name), \
+ .fails = true, \
+}

struct core_reloc_test_case {
const char *case_name;
@@ -23,6 +50,13 @@ static struct core_reloc_test_case test_cases[] = {
.output = "\1", /* true */
.output_len = 1,
},
+
+ /* validate BPF program can use multiple flavors to match against
+ * single target BTF type
+ */
+ FLAVORS_CASE(flavors),
+
+ FLAVORS_ERR_CASE(flavors__err_wrong_name),
};

struct data {
diff --git a/tools/testing/selftests/bpf/progs/btf__core_reloc_flavors.c b/tools/testing/selftests/bpf/progs/btf__core_reloc_flavors.c
new file mode 100644
index 000000000000..b74455b91227
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/btf__core_reloc_flavors.c
@@ -0,0 +1,3 @@
+#include "core_reloc_types.h"
+
+void f(struct core_reloc_flavors x) {}
diff --git a/tools/testing/selftests/bpf/progs/btf__core_reloc_flavors__err_wrong_name.c b/tools/testing/selftests/bpf/progs/btf__core_reloc_flavors__err_wrong_name.c
new file mode 100644
index 000000000000..7b6035f86ee6
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/btf__core_reloc_flavors__err_wrong_name.c
@@ -0,0 +1,3 @@
+#include "core_reloc_types.h"
+
+void f(struct core_reloc_flavors__err_wrong_name x) {}
diff --git a/tools/testing/selftests/bpf/progs/core_reloc_types.h b/tools/testing/selftests/bpf/progs/core_reloc_types.h
new file mode 100644
index 000000000000..33b0c6a61912
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/core_reloc_types.h
@@ -0,0 +1,15 @@
+/*
+ * FLAVORS
+ */
+struct core_reloc_flavors {
+ int a;
+ int b;
+ int c;
+};
+
+/* this is not a flavor, as it doesn't have triple underscore */
+struct core_reloc_flavors__err_wrong_name {
+ int a;
+ int b;
+ int c;
+};
diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_flavors.c b/tools/testing/selftests/bpf/progs/test_core_reloc_flavors.c
new file mode 100644
index 000000000000..9fda73e87972
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_flavors.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"
+
+char _license[] SEC("license") = "GPL";
+
+static volatile struct data {
+ char in[256];
+ char out[256];
+} data;
+
+struct core_reloc_flavors {
+ int a;
+ int b;
+ int c;
+};
+
+/* local flavor with reversed layout */
+struct core_reloc_flavors___reversed {
+ int c;
+ int b;
+ int a;
+};
+
+/* local flavor with nested/overlapping layout */
+struct core_reloc_flavors___weird {
+ struct {
+ int b;
+ };
+ /* a and c overlap in local flavor, but this should still work
+ * correctly with target original flavor
+ */
+ union {
+ int a;
+ int c;
+ };
+};
+
+SEC("raw_tracepoint/sys_enter")
+int test_core_flavors(void *ctx)
+{
+ struct core_reloc_flavors *in_orig = (void *)&data.in;
+ struct core_reloc_flavors___reversed *in_rev = (void *)&data.in;
+ struct core_reloc_flavors___weird *in_weird = (void *)&data.in;
+ struct core_reloc_flavors *out = (void *)&data.out;
+
+ /* read a using weird layout */
+ if (BPF_CORE_READ(&out->a, &in_weird->a))
+ return 1;
+ /* read b using reversed layout */
+ if (BPF_CORE_READ(&out->b, &in_rev->b))
+ return 1;
+ /* read c using original layout */
+ if (BPF_CORE_READ(&out->c, &in_orig->c))
+ return 1;
+
+ return 0;
+}
+
--
2.17.1