Re: [PATCHv2 bpf-next 1/7] selftests/bpf: Move kfunc exports to bpf_testmod/bpf_testmod_kfunc.h

David Vernet
2023-01-30T15:16:19Z

On Mon, Jan 30, 2023 at 09:55:34AM +0100, Jiri Olsa wrote:
> Move all kfunc exports into separate 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.

Nice, good call.

>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> .../bpf/bpf_testmod/bpf_testmod_kfunc.h | 92 +++++++++++++++++++
> tools/testing/selftests/bpf/progs/cb_refs.c | 4 +-
> .../selftests/bpf/progs/jit_probe_mem.c | 4 +-
> .../bpf/progs/kfunc_call_destructive.c | 3 +-
> .../selftests/bpf/progs/kfunc_call_fail.c | 9 +-
> .../selftests/bpf/progs/kfunc_call_race.c | 3 +-
> .../selftests/bpf/progs/kfunc_call_test.c | 16 +---
> .../bpf/progs/kfunc_call_test_subprog.c | 17 +++-
> tools/testing/selftests/bpf/progs/map_kptr.c | 6 +-
> .../selftests/bpf/progs/map_kptr_fail.c | 5 +-
> 10 files changed, 114 insertions(+), 45 deletions(-)
> create mode 100644 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
>
> diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
> new file mode 100644
> index 000000000000..164cbae2b0d7
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h

Should we update the selftests Makefile to rebuild progs when the testmod
changes? Something like:

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index e79039726173..ed0fb32aa855 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -438,6 +438,7 @@ $(TRUNNER_BPF_OBJS): $(TRUNNER_OUTPUT)/%.bpf.o: \
$(TRUNNER_BPF_PROGS_DIR)/%.c \
$(TRUNNER_BPF_PROGS_DIR)/*.h \
$$(INCLUDE_DIR)/vmlinux.h \
+ $(OUTPUT)/bpf_testmod.ko \
$(wildcard $(BPFDIR)/bpf_*.h) \
$(wildcard $(BPFDIR)/*.bpf.h) \
| $(TRUNNER_OUTPUT) $$(BPFOBJ)

> @@ -0,0 +1,92 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef _BPF_TESTMOD_KFUNC_H
> +#define _BPF_TESTMOD_KFUNC_H
> +
> +#ifndef __ksym
> +#define __ksym __attribute__((section(".ksyms")))
> +#endif

What about doing something like this:

#ifndef __KERNEL__
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#else
#define __ksym
#endif

Thoughts?

> +
> +struct prog_test_pass1 {
> + int x0;
> + struct {
> + int x1;
> + struct {
> + int x2;
> + struct {
> + int x3;
> + };
> + };
> + };
> +};
> +
> +struct prog_test_pass2 {
> + int len;
> + short arr1[4];
> + struct {
> + char arr2[4];
> + unsigned long arr3[8];
> + } x;
> +};
> +
> +struct prog_test_fail1 {
> + void *p;
> + int x;
> +};
> +
> +struct prog_test_fail2 {
> + int x8;
> + struct prog_test_pass1 x;
> +};
> +
> +struct prog_test_fail3 {
> + int len;
> + char arr1[2];
> + char arr2[];
> +};
> +
> +struct prog_test_member1 {
> + int a;
> +};
> +
> +struct prog_test_member {
> + struct prog_test_member1 m;
> + int c;
> +};
> +
> +struct prog_test_ref_kfunc {
> + int a;
> + int b;
> + struct prog_test_member memb;
> + struct prog_test_ref_kfunc *next;
> + refcount_t cnt;
> +};
> +
> +extern struct prog_test_ref_kfunc *
> +bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr) __ksym;
> +extern struct prog_test_ref_kfunc *
> +bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b) __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;
> +
> +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;

nit: Can we remove extern from all of these function signatures? Doesn't
really matter much to leave it there, but given that the keyword does
nothing for functions it feels unnecessary / noisy.

> +
> +#endif /* _BPF_TESTMOD_KFUNC_H */
> diff --git a/tools/testing/selftests/bpf/progs/cb_refs.c b/tools/testing/selftests/bpf/progs/cb_refs.c
> index 7653df1bc787..823901c1b839 100644
> --- a/tools/testing/selftests/bpf/progs/cb_refs.c
> +++ b/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_ref *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;
> diff --git a/tools/testing/selftests/bpf/progs/jit_probe_mem.c b/tools/testing/selftests/bpf/progs/jit_probe_mem.c
> index 2d2e61470794..96207f126054 100644
> --- a/tools/testing/selftests/bpf/progs/jit_probe_mem.c
> +++ b/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_ref *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)
> {
> diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c b/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
> index 767472bc5a97..6a9b13a79ae8 100644
> --- a/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
> +++ b/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c
> @@ -1,8 +1,7 @@
> // 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)
> diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
> index b98313d391c6..e857d1c4cf5b 100644
> --- a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
> +++ b/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];
> diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_race.c b/tools/testing/selftests/bpf/progs/kfunc_call_race.c
> index 4e8fed75a4e0..a9558e434611 100644
> --- a/tools/testing/selftests/bpf/progs/kfunc_call_race.c
> +++ b/tools/testing/selftests/bpf/progs/kfunc_call_race.c
> @@ -1,8 +1,7 @@
> // 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)
> diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
> index d91c58d06d38..d2fe17e2b433 100644
> --- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
> +++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
> @@ -2,21 +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;
> +#include "bpf_testmod/bpf_testmod_kfunc.h"
>
> SEC("tc")
> int kfunc_call_test4(struct __sk_buff *skb)
> diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c b/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
> index c1fdecabeabf..f74c78bb5efd 100644
> --- a/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
> +++ b/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
> @@ -4,10 +4,21 @@
> #include <bpf/bpf_helpers.h>
> #include "bpf_tcp_helpers.h"
>
> +/*
> + * We can't include vmlinux.h, because it conflicts with bpf_tcp_helpers.h,
> + * but we need refcount_t typedef for bpf_testmod_kfunc.h.
> + * Adding it directly.
> + */
> +typedef struct {
> + int counter;
> +} atomic_t;
> +typedef struct refcount_struct {
> + atomic_t refs;
> +} refcount_t;

Meh, this is kind of unfortunate, but OK, not the end of the world.
Don't really see an easy way to resolve these types of typedef / include
spaghetti issues in a general way.

As an alternative, it looks like this also works:

diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c b/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
index f74c78bb5efd..7b3472ebc445 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test_subprog.c
@@ -1,21 +1,8 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */
-#include <linux/bpf.h>
+#include <linux/types.h>
#include <bpf/bpf_helpers.h>
-#include "bpf_tcp_helpers.h"
-
-/*
- * We can't include vmlinux.h, because it conflicts with bpf_tcp_helpers.h,
- * but we need refcount_t typedef for bpf_testmod_kfunc.h.
- * Adding it directly.
- */
-typedef struct {
- int counter;
-} atomic_t;
-typedef struct refcount_struct {
- atomic_t refs;
-} refcount_t;
-
+#include <vmlinux.h>
#include "bpf_testmod/bpf_testmod_kfunc.h"

extern const int bpf_prog_active __ksym;
@@ -39,7 +26,7 @@ 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);
}

Thoughts?

> +
> +#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;
>
> diff --git a/tools/testing/selftests/bpf/progs/map_kptr.c b/tools/testing/selftests/bpf/progs/map_kptr.c
> index eb8217803493..d53474f5b05b 100644
> --- a/tools/testing/selftests/bpf/progs/map_kptr.c
> +++ b/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 *unref_ptr;
> @@ -57,11 +58,6 @@ 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 struct prog_test_ref_kfunc *
> -bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b) __ksym;
> -extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
> -
> static void test_kptr_unref(struct map_value *v)
> {
> struct prog_test_ref_kfunc *p;
> diff --git a/tools/testing/selftests/bpf/progs/map_kptr_fail.c b/tools/testing/selftests/bpf/progs/map_kptr_fail.c
> index 760e41e1a632..1358a7c9e399 100644
> --- a/tools/testing/selftests/bpf/progs/map_kptr_fail.c
> +++ b/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];
> @@ -19,10 +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 struct prog_test_ref_kfunc *
> -bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b) __ksym;
> -
> SEC("?tc")
> __failure __msg("kptr access size must be BPF_DW")
> int size_not_bpf_dw(struct __sk_buff *ctx)
> --
> 2.39.1
>