selftests/bpf: add CO-RE relocs struct flavors tests

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>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
index 4323a45..59fd9cb 100644 (file)
--- 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 (file)
index 0000000..b74455b
--- /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 (file)
index 0000000..7b6035f
--- /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 (file)
index 0000000..33b0c6a
--- /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 (file)
index 0000000..9fda73e
--- /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;
+}
+