[PATCH v4 bpf-next 14/16] selftests/bpf: Additional test for CO-RE in the kernel.

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

From: Alexei Starovoitov <ast@kernel.org>

Additional test where randmap() function is appended to three different bpf
programs. That action checks struct bpf_core_relo replication logic and offset
adjustment.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 tools/testing/selftests/bpf/Makefile          |  2 +-
 .../selftests/bpf/prog_tests/core_kern.c      | 14 +++
 tools/testing/selftests/bpf/progs/core_kern.c | 87 +++++++++++++++++++
 3 files changed, 102 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/core_kern.c
 create mode 100644 tools/testing/selftests/bpf/progs/core_kern.c

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 4fd040f5944b..139d7e5e0a5f 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -326,7 +326,7 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h		\
 
 LSKELS := kfunc_call_test.c fentry_test.c fexit_test.c fexit_sleep.c \
 	test_ringbuf.c atomics.c trace_printk.c trace_vprintk.c \
-	map_ptr_kern.c
+	map_ptr_kern.c core_kern.c
 # Generate both light skeleton and libbpf skeleton for these
 LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test_subprog.c
 SKEL_BLACKLIST += $$(LSKELS)
diff --git a/tools/testing/selftests/bpf/prog_tests/core_kern.c b/tools/testing/selftests/bpf/prog_tests/core_kern.c
new file mode 100644
index 000000000000..561c5185d886
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/core_kern.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include "test_progs.h"
+#include "core_kern.lskel.h"
+
+void test_core_kern_lskel(void)
+{
+	struct core_kern_lskel *skel;
+
+	skel = core_kern_lskel__open_and_load();
+	ASSERT_OK_PTR(skel, "open_and_load");
+	core_kern_lskel__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/core_kern.c b/tools/testing/selftests/bpf/progs/core_kern.c
new file mode 100644
index 000000000000..2a40eec581b1
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/core_kern.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include "vmlinux.h"
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+#define ATTR __always_inline
+#include "test_jhash.h"
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, u32);
+	__uint(max_entries, 256);
+} array1 SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, u32);
+	__uint(max_entries, 256);
+} array2 SEC(".maps");
+
+static __noinline int randmap(int v, const struct net_device *dev)
+{
+	struct bpf_map *map = (struct bpf_map *)&array1;
+	int key = bpf_get_prandom_u32() & 0xff;
+	int *val;
+
+	if (bpf_get_prandom_u32() & 1)
+		map = (struct bpf_map *)&array2;
+
+	val = bpf_map_lookup_elem(map, &key);
+	if (val)
+		*val = bpf_get_prandom_u32() + v + dev->mtu;
+
+	return 0;
+}
+
+SEC("tp_btf/xdp_devmap_xmit")
+int BPF_PROG(tp_xdp_devmap_xmit_multi, const struct net_device
+	     *from_dev, const struct net_device *to_dev, int sent, int drops,
+	     int err)
+{
+	return randmap(from_dev->ifindex, from_dev);
+}
+
+SEC("fentry/eth_type_trans")
+int BPF_PROG(fentry_eth_type_trans, struct sk_buff *skb,
+	     struct net_device *dev, unsigned short protocol)
+{
+	return randmap(dev->ifindex + skb->len, dev);
+}
+
+SEC("fexit/eth_type_trans")
+int BPF_PROG(fexit_eth_type_trans, struct sk_buff *skb,
+	     struct net_device *dev, unsigned short protocol)
+{
+	return randmap(dev->ifindex + skb->len, dev);
+}
+
+SEC("tc")
+int balancer_ingress(struct __sk_buff *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	void *ptr;
+	int ret = 0, nh_off, i = 0;
+
+	nh_off = 14;
+
+	/* pragma unroll doesn't work on large loops */
+
+#define C do { \
+	ptr = data + i; \
+	if (ptr + nh_off > data_end) \
+		break; \
+	ctx->tc_index = jhash(ptr, nh_off, ctx->cb[0] + i++); \
+	} while (0);
+#define C30 C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;C;
+	C30;C30;C30; /* 90 calls */
+	return 0;
+}
+
+char LICENSE[] SEC("license") = "GPL";
-- 
2.30.2