selftests/bpf: Test TYPE_EXISTS and TYPE_SIZE CO-RE relocations

Add selftests for TYPE_EXISTS and TYPE_SIZE relocations, testing correctness
of relocations and handling of type compatiblity/incompatibility.

If __builtin_preserve_type_info() is not supported by compiler, skip tests.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200819194519.3375898-3-andriin@fb.com

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

@@ -177,14 +177,13 @@
 	.fails = true,							\
 }
 
-#define EXISTENCE_CASE_COMMON(name)					\
+#define FIELD_EXISTS_CASE_COMMON(name)					\
 	.case_name = #name,						\
 	.bpf_obj_file = "test_core_reloc_existence.o",			\
-	.btf_src_file = "btf__core_reloc_" #name ".o",			\
-	.relaxed_core_relocs = true
+	.btf_src_file = "btf__core_reloc_" #name ".o"			\
 
-#define EXISTENCE_ERR_CASE(name) {					\
-	EXISTENCE_CASE_COMMON(name),					\
+#define FIELD_EXISTS_ERR_CASE(name) {					\
+	FIELD_EXISTS_CASE_COMMON(name),					\
 	.fails = true,							\
 }
 
@@ -253,6 +252,23 @@
 	.fails = true,							\
 }
 
+#define TYPE_BASED_CASE_COMMON(name)					\
+	.case_name = #name,						\
+	.bpf_obj_file = "test_core_reloc_type_based.o",		\
+	.btf_src_file = "btf__core_reloc_" #name ".o"			\
+
+#define TYPE_BASED_CASE(name, ...) {					\
+	TYPE_BASED_CASE_COMMON(name),					\
+	.output = STRUCT_TO_CHAR_PTR(core_reloc_type_based_output)	\
+			__VA_ARGS__,					\
+	.output_len = sizeof(struct core_reloc_type_based_output),	\
+}
+
+#define TYPE_BASED_ERR_CASE(name) {					\
+	TYPE_BASED_CASE_COMMON(name),					\
+	.fails = true,							\
+}
+
 struct core_reloc_test_case {
 	const char *case_name;
 	const char *bpf_obj_file;
@@ -364,7 +380,7 @@ static struct core_reloc_test_case test_cases[] = {
 
 	/* validate field existence checks */
 	{
-		EXISTENCE_CASE_COMMON(existence),
+		FIELD_EXISTS_CASE_COMMON(existence),
 		.input = STRUCT_TO_CHAR_PTR(core_reloc_existence) {
 			.a = 1,
 			.b = 2,
@@ -388,7 +404,7 @@ static struct core_reloc_test_case test_cases[] = {
 		.output_len = sizeof(struct core_reloc_existence_output),
 	},
 	{
-		EXISTENCE_CASE_COMMON(existence___minimal),
+		FIELD_EXISTS_CASE_COMMON(existence___minimal),
 		.input = STRUCT_TO_CHAR_PTR(core_reloc_existence___minimal) {
 			.a = 42,
 		},
@@ -408,12 +424,12 @@ static struct core_reloc_test_case test_cases[] = {
 		.output_len = sizeof(struct core_reloc_existence_output),
 	},
 
-	EXISTENCE_ERR_CASE(existence__err_int_sz),
-	EXISTENCE_ERR_CASE(existence__err_int_type),
-	EXISTENCE_ERR_CASE(existence__err_int_kind),
-	EXISTENCE_ERR_CASE(existence__err_arr_kind),
-	EXISTENCE_ERR_CASE(existence__err_arr_value_type),
-	EXISTENCE_ERR_CASE(existence__err_struct_type),
+	FIELD_EXISTS_ERR_CASE(existence__err_int_sz),
+	FIELD_EXISTS_ERR_CASE(existence__err_int_type),
+	FIELD_EXISTS_ERR_CASE(existence__err_int_kind),
+	FIELD_EXISTS_ERR_CASE(existence__err_arr_kind),
+	FIELD_EXISTS_ERR_CASE(existence__err_arr_value_type),
+	FIELD_EXISTS_ERR_CASE(existence__err_struct_type),
 
 	/* bitfield relocation checks */
 	BITFIELDS_CASE(bitfields, {
@@ -453,11 +469,73 @@ static struct core_reloc_test_case test_cases[] = {
 	SIZE_CASE(size),
 	SIZE_CASE(size___diff_sz),
 	SIZE_ERR_CASE(size___err_ambiguous),
+
+	/* validate type existence and size relocations */
+	TYPE_BASED_CASE(type_based, {
+		.struct_exists = 1,
+		.union_exists = 1,
+		.enum_exists = 1,
+		.typedef_named_struct_exists = 1,
+		.typedef_anon_struct_exists = 1,
+		.typedef_struct_ptr_exists = 1,
+		.typedef_int_exists = 1,
+		.typedef_enum_exists = 1,
+		.typedef_void_ptr_exists = 1,
+		.typedef_func_proto_exists = 1,
+		.typedef_arr_exists = 1,
+		.struct_sz = sizeof(struct a_struct),
+		.union_sz = sizeof(union a_union),
+		.enum_sz = sizeof(enum an_enum),
+		.typedef_named_struct_sz = sizeof(named_struct_typedef),
+		.typedef_anon_struct_sz = sizeof(anon_struct_typedef),
+		.typedef_struct_ptr_sz = sizeof(struct_ptr_typedef),
+		.typedef_int_sz = sizeof(int_typedef),
+		.typedef_enum_sz = sizeof(enum_typedef),
+		.typedef_void_ptr_sz = sizeof(void_ptr_typedef),
+		.typedef_func_proto_sz = sizeof(func_proto_typedef),
+		.typedef_arr_sz = sizeof(arr_typedef),
+	}),
+	TYPE_BASED_CASE(type_based___all_missing, {
+		/* all zeros */
+	}),
+	TYPE_BASED_CASE(type_based___diff_sz, {
+		.struct_exists = 1,
+		.union_exists = 1,
+		.enum_exists = 1,
+		.typedef_named_struct_exists = 1,
+		.typedef_anon_struct_exists = 1,
+		.typedef_struct_ptr_exists = 1,
+		.typedef_int_exists = 1,
+		.typedef_enum_exists = 1,
+		.typedef_void_ptr_exists = 1,
+		.typedef_func_proto_exists = 1,
+		.typedef_arr_exists = 1,
+		.struct_sz = sizeof(struct a_struct___diff_sz),
+		.union_sz = sizeof(union a_union___diff_sz),
+		.enum_sz = sizeof(enum an_enum___diff_sz),
+		.typedef_named_struct_sz = sizeof(named_struct_typedef___diff_sz),
+		.typedef_anon_struct_sz = sizeof(anon_struct_typedef___diff_sz),
+		.typedef_struct_ptr_sz = sizeof(struct_ptr_typedef___diff_sz),
+		.typedef_int_sz = sizeof(int_typedef___diff_sz),
+		.typedef_enum_sz = sizeof(enum_typedef___diff_sz),
+		.typedef_void_ptr_sz = sizeof(void_ptr_typedef___diff_sz),
+		.typedef_func_proto_sz = sizeof(func_proto_typedef___diff_sz),
+		.typedef_arr_sz = sizeof(arr_typedef___diff_sz),
+	}),
+	TYPE_BASED_CASE(type_based___incompat, {
+		.enum_exists = 1,
+		.enum_sz = sizeof(enum an_enum),
+	}),
+	TYPE_BASED_CASE(type_based___fn_wrong_args, {
+		.struct_exists = 1,
+		.struct_sz = sizeof(struct a_struct),
+	}),
 };
 
 struct data {
 	char in[256];
 	char out[256];
+	bool skip;
 	uint64_t my_pid_tgid;
 };
 
@@ -516,15 +594,10 @@ void test_core_reloc(void)
 		load_attr.log_level = 0;
 		load_attr.target_btf_path = test_case->btf_src_file;
 		err = bpf_object__load_xattr(&load_attr);
-		if (test_case->fails) {
-			CHECK(!err, "obj_load_fail",
-			      "should fail to load prog '%s'\n", probe_name);
+		if (err) {
+			if (!test_case->fails)
+				CHECK(false, "obj_load", "failed to load prog '%s': %d\n", probe_name, err);
 			goto cleanup;
-		} else {
-			if (CHECK(err, "obj_load",
-				  "failed to load prog '%s': %d\n",
-				  probe_name, err))
-				goto cleanup;
 		}
 
 		data_map = bpf_object__find_map_by_name(obj, "test_cor.bss");
@@ -552,6 +625,16 @@ void test_core_reloc(void)
 		/* trigger test run */
 		usleep(1);
 
+		if (data->skip) {
+			test__skip();
+			goto cleanup;
+		}
+
+		if (test_case->fails) {
+			CHECK(false, "obj_load_fail", "should fail to load prog '%s'\n", probe_name);
+			goto cleanup;
+		}
+
 		equal = memcmp(data->out, test_case->output,
 			       test_case->output_len) == 0;
 		if (CHECK(!equal, "check_result",

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

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

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

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

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

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

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

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

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

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

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

@@ -652,7 +652,7 @@ struct core_reloc_misc_extensible {
 };
 
 /*
- * EXISTENCE
+ * FIELD EXISTENCE
  */
 struct core_reloc_existence_output {
 	int a_exists;
@@ -834,3 +834,203 @@ struct core_reloc_size___err_ambiguous2 {
 	void *ptr_field;
 	enum { VALUE___2 = 123 } enum_field;
 };
+
+/*
+ * TYPE EXISTENCE & SIZE
+ */
+struct core_reloc_type_based_output {
+	bool struct_exists;
+	bool union_exists;
+	bool enum_exists;
+	bool typedef_named_struct_exists;
+	bool typedef_anon_struct_exists;
+	bool typedef_struct_ptr_exists;
+	bool typedef_int_exists;
+	bool typedef_enum_exists;
+	bool typedef_void_ptr_exists;
+	bool typedef_func_proto_exists;
+	bool typedef_arr_exists;
+
+	int struct_sz;
+	int union_sz;
+	int enum_sz;
+	int typedef_named_struct_sz;
+	int typedef_anon_struct_sz;
+	int typedef_struct_ptr_sz;
+	int typedef_int_sz;
+	int typedef_enum_sz;
+	int typedef_void_ptr_sz;
+	int typedef_func_proto_sz;
+	int typedef_arr_sz;
+};
+
+struct a_struct {
+	int x;
+};
+
+union a_union {
+	int y;
+	int z;
+};
+
+typedef struct a_struct named_struct_typedef;
+
+typedef struct { int x, y, z; } anon_struct_typedef;
+
+typedef struct {
+	int a, b, c;
+} *struct_ptr_typedef;
+
+enum an_enum {
+	AN_ENUM_VAL1 = 1,
+	AN_ENUM_VAL2 = 2,
+	AN_ENUM_VAL3 = 3,
+};
+
+typedef int int_typedef;
+
+typedef enum { TYPEDEF_ENUM_VAL1, TYPEDEF_ENUM_VAL2 } enum_typedef;
+
+typedef void *void_ptr_typedef;
+
+typedef int (*func_proto_typedef)(long);
+
+typedef char arr_typedef[20];
+
+struct core_reloc_type_based {
+	struct a_struct f1;
+	union a_union f2;
+	enum an_enum f3;
+	named_struct_typedef f4;
+	anon_struct_typedef f5;
+	struct_ptr_typedef f6;
+	int_typedef f7;
+	enum_typedef f8;
+	void_ptr_typedef f9;
+	func_proto_typedef f10;
+	arr_typedef f11;
+};
+
+/* no types in target */
+struct core_reloc_type_based___all_missing {
+};
+
+/* different type sizes, extra modifiers, anon vs named enums, etc */
+struct a_struct___diff_sz {
+	long x;
+	int y;
+	char z;
+};
+
+union a_union___diff_sz {
+	char yy;
+	char zz;
+};
+
+typedef struct a_struct___diff_sz named_struct_typedef___diff_sz;
+
+typedef struct { long xx, yy, zzz; } anon_struct_typedef___diff_sz;
+
+typedef struct {
+	char aa[1], bb[2], cc[3];
+} *struct_ptr_typedef___diff_sz;
+
+enum an_enum___diff_sz {
+	AN_ENUM_VAL1___diff_sz = 0x123412341234,
+	AN_ENUM_VAL2___diff_sz = 2,
+};
+
+typedef unsigned long int_typedef___diff_sz;
+
+typedef enum an_enum___diff_sz enum_typedef___diff_sz;
+
+typedef const void * const void_ptr_typedef___diff_sz;
+
+typedef int_typedef___diff_sz (*func_proto_typedef___diff_sz)(char);
+
+typedef int arr_typedef___diff_sz[2];
+
+struct core_reloc_type_based___diff_sz {
+	struct a_struct___diff_sz f1;
+	union a_union___diff_sz f2;
+	enum an_enum___diff_sz f3;
+	named_struct_typedef___diff_sz f4;
+	anon_struct_typedef___diff_sz f5;
+	struct_ptr_typedef___diff_sz f6;
+	int_typedef___diff_sz f7;
+	enum_typedef___diff_sz f8;
+	void_ptr_typedef___diff_sz f9;
+	func_proto_typedef___diff_sz f10;
+	arr_typedef___diff_sz f11;
+};
+
+/* incompatibilities between target and local types */
+union a_struct___incompat { /* union instead of struct */
+	int x;
+};
+
+struct a_union___incompat { /* struct instead of union */
+	int y;
+	int z;
+};
+
+/* typedef to union, not to struct */
+typedef union a_struct___incompat named_struct_typedef___incompat;
+
+/* typedef to void pointer, instead of struct */
+typedef void *anon_struct_typedef___incompat;
+
+/* extra pointer indirection */
+typedef struct {
+	int a, b, c;
+} **struct_ptr_typedef___incompat;
+
+/* typedef of a struct with int, instead of int */
+typedef struct { int x; } int_typedef___incompat;
+
+/* typedef to func_proto, instead of enum */
+typedef int (*enum_typedef___incompat)(void);
+
+/* pointer to char instead of void */
+typedef char *void_ptr_typedef___incompat;
+
+/* void return type instead of int */
+typedef void (*func_proto_typedef___incompat)(long);
+
+/* multi-dimensional array instead of a single-dimensional */
+typedef int arr_typedef___incompat[20][2];
+
+struct core_reloc_type_based___incompat {
+	union a_struct___incompat f1;
+	struct a_union___incompat f2;
+	/* the only valid one is enum, to check that something still succeeds */
+	enum an_enum f3;
+	named_struct_typedef___incompat f4;
+	anon_struct_typedef___incompat f5;
+	struct_ptr_typedef___incompat f6;
+	int_typedef___incompat f7;
+	enum_typedef___incompat f8;
+	void_ptr_typedef___incompat f9;
+	func_proto_typedef___incompat f10;
+	arr_typedef___incompat f11;
+};
+
+/* func_proto with incompatible signature */
+typedef void (*func_proto_typedef___fn_wrong_ret1)(long);
+typedef int * (*func_proto_typedef___fn_wrong_ret2)(long);
+typedef struct { int x; } int_struct_typedef;
+typedef int_struct_typedef (*func_proto_typedef___fn_wrong_ret3)(long);
+typedef int (*func_proto_typedef___fn_wrong_arg)(void *);
+typedef int (*func_proto_typedef___fn_wrong_arg_cnt1)(long, long);
+typedef int (*func_proto_typedef___fn_wrong_arg_cnt2)(void);
+
+struct core_reloc_type_based___fn_wrong_args {
+	/* one valid type to make sure relos still work */
+	struct a_struct f1;
+	func_proto_typedef___fn_wrong_ret1 f2;
+	func_proto_typedef___fn_wrong_ret2 f3;
+	func_proto_typedef___fn_wrong_ret3 f4;
+	func_proto_typedef___fn_wrong_arg f5;
+	func_proto_typedef___fn_wrong_arg_cnt1 f6;
+	func_proto_typedef___fn_wrong_arg_cnt2 f7;
+};

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

@@ -3,6 +3,7 @@
 
 #include <linux/bpf.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_core_read.h>
 
@@ -11,6 +12,7 @@ char _license[] SEC("license") = "GPL";
 struct {
 	char in[256];
 	char out[256];
+	bool skip;
 	uint64_t my_pid_tgid;
 } data = {};
 

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

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+
+#include <linux/bpf.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+	char in[256];
+	char out[256];
+	bool skip;
+} data = {};
+
+struct a_struct {
+	int x;
+};
+
+union a_union {
+	int y;
+	int z;
+};
+
+typedef struct a_struct named_struct_typedef;
+
+typedef struct { int x, y, z; } anon_struct_typedef;
+
+typedef struct {
+	int a, b, c;
+} *struct_ptr_typedef;
+
+enum an_enum {
+	AN_ENUM_VAL1 = 1,
+	AN_ENUM_VAL2 = 2,
+	AN_ENUM_VAL3 = 3,
+};
+
+typedef int int_typedef;
+
+typedef enum { TYPEDEF_ENUM_VAL1, TYPEDEF_ENUM_VAL2 } enum_typedef;
+
+typedef void *void_ptr_typedef;
+
+typedef int (*func_proto_typedef)(long);
+
+typedef char arr_typedef[20];
+
+struct core_reloc_type_based {
+	struct a_struct f1;
+	union a_union f2;
+	enum an_enum f3;
+	named_struct_typedef f4;
+	anon_struct_typedef f5;
+	struct_ptr_typedef f6;
+	int_typedef f7;
+	enum_typedef f8;
+	void_ptr_typedef f9;
+	func_proto_typedef f10;
+	arr_typedef f11;
+};
+
+struct core_reloc_type_based_output {
+	bool struct_exists;
+	bool union_exists;
+	bool enum_exists;
+	bool typedef_named_struct_exists;
+	bool typedef_anon_struct_exists;
+	bool typedef_struct_ptr_exists;
+	bool typedef_int_exists;
+	bool typedef_enum_exists;
+	bool typedef_void_ptr_exists;
+	bool typedef_func_proto_exists;
+	bool typedef_arr_exists;
+
+	int struct_sz;
+	int union_sz;
+	int enum_sz;
+	int typedef_named_struct_sz;
+	int typedef_anon_struct_sz;
+	int typedef_struct_ptr_sz;
+	int typedef_int_sz;
+	int typedef_enum_sz;
+	int typedef_void_ptr_sz;
+	int typedef_func_proto_sz;
+	int typedef_arr_sz;
+};
+
+SEC("raw_tracepoint/sys_enter")
+int test_core_type_based(void *ctx)
+{
+#if __has_builtin(__builtin_preserve_type_info)
+	struct core_reloc_type_based_output *out = (void *)&data.out;
+
+	out->struct_exists = bpf_core_type_exists(struct a_struct);
+	out->union_exists = bpf_core_type_exists(union a_union);
+	out->enum_exists = bpf_core_type_exists(enum an_enum);
+	out->typedef_named_struct_exists = bpf_core_type_exists(named_struct_typedef);
+	out->typedef_anon_struct_exists = bpf_core_type_exists(anon_struct_typedef);
+	out->typedef_struct_ptr_exists = bpf_core_type_exists(struct_ptr_typedef);
+	out->typedef_int_exists = bpf_core_type_exists(int_typedef);
+	out->typedef_enum_exists = bpf_core_type_exists(enum_typedef);
+	out->typedef_void_ptr_exists = bpf_core_type_exists(void_ptr_typedef);
+	out->typedef_func_proto_exists = bpf_core_type_exists(func_proto_typedef);
+	out->typedef_arr_exists = bpf_core_type_exists(arr_typedef);
+
+	out->struct_sz = bpf_core_type_size(struct a_struct);
+	out->union_sz = bpf_core_type_size(union a_union);
+	out->enum_sz = bpf_core_type_size(enum an_enum);
+	out->typedef_named_struct_sz = bpf_core_type_size(named_struct_typedef);
+	out->typedef_anon_struct_sz = bpf_core_type_size(anon_struct_typedef);
+	out->typedef_struct_ptr_sz = bpf_core_type_size(struct_ptr_typedef);
+	out->typedef_int_sz = bpf_core_type_size(int_typedef);
+	out->typedef_enum_sz = bpf_core_type_size(enum_typedef);
+	out->typedef_void_ptr_sz = bpf_core_type_size(void_ptr_typedef);
+	out->typedef_func_proto_sz = bpf_core_type_size(func_proto_typedef);
+	out->typedef_arr_sz = bpf_core_type_size(arr_typedef);
+#else
+	data.skip = true;
+#endif
+	return 0;
+}