selftests/bpf: Move kfunc exports to bpf_testmod/bpf_testmod_kfunc.h

Move all kfunc exports into separate bpf_testmod_kfunc.h header file
and include it in tests that need it.

We will move all test kfuncs into bpf_testmod in following change,
so it's convenient to have declarations in single place.

The bpf_testmod_kfunc.h is included by both bpf_testmod and bpf
programs that use test kfuncs.

As suggested by David, the bpf_testmod_kfunc.h includes vmlinux.h
and bpf/bpf_helpers.h for bpf programs build, so the declarations
have proper __ksym attribute and we can resolve all the structs.

Note in kfunc_call_test_subprog.c we can no longer use the sk_state
define from bpf_tcp_helpers.h (because it clashed with vmlinux.h)
and we need to address __sk_common.skc_state field directly.
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230515133756.1658301-3-jolsa@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _BPF_TESTMOD_KFUNC_H
+#define _BPF_TESTMOD_KFUNC_H
+
+#ifndef __KERNEL__
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#else
+#define __ksym
+#endif
+
+extern struct prog_test_ref_kfunc *
+bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr) __ksym;
+extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
+void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) __ksym;
+
+extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
+extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
+extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
+extern int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
+extern void bpf_kfunc_call_int_mem_release(int *p) __ksym;
+extern u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused) __ksym;
+
+extern void bpf_testmod_test_mod_kfunc(int i) __ksym;
+
+extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
+				__u32 c, __u64 d) __ksym;
+extern int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym;
+extern struct sock *bpf_kfunc_call_test3(struct sock *sk) __ksym;
+extern long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym;
+
+extern void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb) __ksym;
+extern void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym;
+extern void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym;
+extern void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;
+
+extern void bpf_kfunc_call_test_destructive(void) __ksym;
+
+#endif /* _BPF_TESTMOD_KFUNC_H */

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

@@ -2,6 +2,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct map_value {
 	struct prog_test_ref_kfunc __kptr *ptr;
@@ -14,9 +15,6 @@ struct {
 	__uint(max_entries, 16);
 } array_map SEC(".maps");
 
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-
 static __noinline int cb1(void *map, void *key, void *value, void *ctx)
 {
 	void *p = *(void **)ctx;

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

@@ -3,13 +3,11 @@
 #include <vmlinux.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 static struct prog_test_ref_kfunc __kptr *v;
 long total_sum = -1;
 
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-
 SEC("tc")
 int test_jit_probe_mem(struct __sk_buff *ctx)
 {

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

 // SPDX-License-Identifier: GPL-2.0
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
-extern void bpf_kfunc_call_test_destructive(void) __ksym;
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 SEC("tc")
 int kfunc_destructive_test(void)

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

@@ -2,14 +2,7 @@
 /* Copyright (c) 2021 Facebook */
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
-extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
-extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
-extern int *bpf_kfunc_call_test_acq_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
-extern void bpf_kfunc_call_int_mem_release(int *p) __ksym;
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct syscall_test_args {
 	__u8 data[16];

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

 // SPDX-License-Identifier: GPL-2.0
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
-extern void bpf_testmod_test_mod_kfunc(int i) __ksym;
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 SEC("tc")
 int kfunc_call_fail(struct __sk_buff *ctx)

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

@@ -2,22 +2,7 @@
 /* Copyright (c) 2021 Facebook */
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
-
-extern long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym;
-extern int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym;
-extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
-				  __u32 c, __u64 d) __ksym;
-
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-extern void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb) __ksym;
-extern void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym;
-extern void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym;
-extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
-extern void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;
-extern int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size) __ksym;
-extern int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size) __ksym;
-extern u32 bpf_kfunc_call_test_static_unused_arg(u32 arg, u32 unused) __ksym;
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 SEC("tc")
 int kfunc_call_test4(struct __sk_buff *skb)

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

 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2021 Facebook */
-#include <linux/bpf.h>
-#include <bpf/bpf_helpers.h>
-#include "bpf_tcp_helpers.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 extern const int bpf_prog_active __ksym;
-extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
-				  __u32 c, __u64 d) __ksym;
-extern struct sock *bpf_kfunc_call_test3(struct sock *sk) __ksym;
 int active_res = -1;
 int sk_state_res = -1;
 
@@ -28,7 +23,7 @@ int __noinline f1(struct __sk_buff *skb)
 	if (active)
 		active_res = *active;
 
-	sk_state_res = bpf_kfunc_call_test3((struct sock *)sk)->sk_state;
+	sk_state_res = bpf_kfunc_call_test3((struct sock *)sk)->__sk_common.skc_state;
 
 	return (__u32)bpf_kfunc_call_test1((struct sock *)sk, 1, 2, 3, 4);
 }

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

@@ -5,7 +5,8 @@
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_core_read.h>
-#include "bpf_experimental.h"
+#include "../bpf_experimental.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct node_data {
 	long key;
@@ -32,8 +33,6 @@ struct map_value {
  */
 struct node_data *just_here_because_btf_bug;
 
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-
 struct {
 	__uint(type, BPF_MAP_TYPE_ARRAY);
 	__type(key, int);

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

@@ -2,6 +2,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_tracing.h>
 #include <bpf/bpf_helpers.h>
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct map_value {
 	struct prog_test_ref_kfunc __kptr_untrusted *unref_ptr;
@@ -114,10 +115,6 @@ DEFINE_MAP_OF_MAP(BPF_MAP_TYPE_HASH_OF_MAPS, hash_map, hash_of_hash_maps);
 DEFINE_MAP_OF_MAP(BPF_MAP_TYPE_HASH_OF_MAPS, hash_malloc_map, hash_of_hash_malloc_maps);
 DEFINE_MAP_OF_MAP(BPF_MAP_TYPE_HASH_OF_MAPS, lru_hash_map, hash_of_lru_hash_maps);
 
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) __ksym;
-
 #define WRITE_ONCE(x, val) ((*(volatile typeof(x) *) &(x)) = (val))
 
 static void test_kptr_unref(struct map_value *v)

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

@@ -4,6 +4,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_core_read.h>
 #include "bpf_misc.h"
+#include "../bpf_testmod/bpf_testmod_kfunc.h"
 
 struct map_value {
 	char buf[8];
@@ -19,9 +20,6 @@ struct array_map {
 	__uint(max_entries, 1);
 } array_map SEC(".maps");
 
-extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
-extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
-
 SEC("?tc")
 __failure __msg("kptr access size must be BPF_DW")
 int size_not_bpf_dw(struct __sk_buff *ctx)