selftests/bpf: Modernize xdp_noinline test w/ skeleton and __noinline

Update xdp_noinline to use BPF skeleton and force __noinline on helper
sub-programs. Also, split existing logic into v4- and v6-only to complicate
sub-program calling patterns (partially overlapped sets of functions for
entry-level BPF programs).
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200903203542.15944-14-andriin@fb.com

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

 // SPDX-License-Identifier: GPL-2.0
 #include <test_progs.h>
 #include <network_helpers.h>
+#include "test_xdp_noinline.skel.h"
 
 void test_xdp_noinline(void)
 {
-	const char *file = "./test_xdp_noinline.o";
 	unsigned int nr_cpus = bpf_num_possible_cpus();
+	struct test_xdp_noinline *skel;
 	struct vip key = {.protocol = 6};
 	struct vip_meta {
 		__u32 flags;
@@ -25,58 +26,42 @@ void test_xdp_noinline(void)
 	} real_def = {.dst = MAGIC_VAL};
 	__u32 ch_key = 11, real_num = 3;
 	__u32 duration, retval, size;
-	int err, i, prog_fd, map_fd;
+	int err, i;
 	__u64 bytes = 0, pkts = 0;
-	struct bpf_object *obj;
 	char buf[128];
 	u32 *magic = (u32 *)buf;
 
-	err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
-	if (CHECK_FAIL(err))
+	skel = test_xdp_noinline__open_and_load();
+	if (CHECK(!skel, "skel_open_and_load", "failed\n"))
 		return;
 
-	map_fd = bpf_find_map(__func__, obj, "vip_map");
-	if (map_fd < 0)
-		goto out;
-	bpf_map_update_elem(map_fd, &key, &value, 0);
+	bpf_map_update_elem(bpf_map__fd(skel->maps.vip_map), &key, &value, 0);
+	bpf_map_update_elem(bpf_map__fd(skel->maps.ch_rings), &ch_key, &real_num, 0);
+	bpf_map_update_elem(bpf_map__fd(skel->maps.reals), &real_num, &real_def, 0);
 
-	map_fd = bpf_find_map(__func__, obj, "ch_rings");
-	if (map_fd < 0)
-		goto out;
-	bpf_map_update_elem(map_fd, &ch_key, &real_num, 0);
-
-	map_fd = bpf_find_map(__func__, obj, "reals");
-	if (map_fd < 0)
-		goto out;
-	bpf_map_update_elem(map_fd, &real_num, &real_def, 0);
-
-	err = bpf_prog_test_run(prog_fd, NUM_ITER, &pkt_v4, sizeof(pkt_v4),
+	err = bpf_prog_test_run(bpf_program__fd(skel->progs.balancer_ingress_v4),
+				NUM_ITER, &pkt_v4, sizeof(pkt_v4),
 				buf, &size, &retval, &duration);
 	CHECK(err || retval != 1 || size != 54 ||
 	      *magic != MAGIC_VAL, "ipv4",
 	      "err %d errno %d retval %d size %d magic %x\n",
 	      err, errno, retval, size, *magic);
 
-	err = bpf_prog_test_run(prog_fd, NUM_ITER, &pkt_v6, sizeof(pkt_v6),
+	err = bpf_prog_test_run(bpf_program__fd(skel->progs.balancer_ingress_v6),
+				NUM_ITER, &pkt_v6, sizeof(pkt_v6),
 				buf, &size, &retval, &duration);
 	CHECK(err || retval != 1 || size != 74 ||
 	      *magic != MAGIC_VAL, "ipv6",
 	      "err %d errno %d retval %d size %d magic %x\n",
 	      err, errno, retval, size, *magic);
 
-	map_fd = bpf_find_map(__func__, obj, "stats");
-	if (map_fd < 0)
-		goto out;
-	bpf_map_lookup_elem(map_fd, &stats_key, stats);
+	bpf_map_lookup_elem(bpf_map__fd(skel->maps.stats), &stats_key, stats);
 	for (i = 0; i < nr_cpus; i++) {
 		bytes += stats[i].bytes;
 		pkts += stats[i].pkts;
 	}
-	if (CHECK_FAIL(bytes != MAGIC_BYTES * NUM_ITER * 2 ||
-		       pkts != NUM_ITER * 2)) {
-		printf("test_xdp_noinline:FAIL:stats %lld %lld\n",
-		       bytes, pkts);
-	}
-out:
-	bpf_object__close(obj);
+	CHECK(bytes != MAGIC_BYTES * NUM_ITER * 2 || pkts != NUM_ITER * 2,
+	      "stats", "bytes %lld pkts %lld\n",
+	      (unsigned long long)bytes, (unsigned long long)pkts);
+	test_xdp_noinline__destroy(skel);
 }

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

@@ -16,7 +16,7 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_endian.h>
 
-static __u32 rol32(__u32 word, unsigned int shift)
+static __always_inline __u32 rol32(__u32 word, unsigned int shift)
 {
 	return (word << shift) | (word >> ((-shift) & 31));
 }
@@ -49,7 +49,7 @@ static __u32 rol32(__u32 word, unsigned int shift)
 
 typedef unsigned int u32;
 
-static __attribute__ ((noinline))
+static __noinline
 u32 jhash(const void *key, u32 length, u32 initval)
 {
 	u32 a, b, c;
@@ -86,7 +86,7 @@ u32 jhash(const void *key, u32 length, u32 initval)
 	return c;
 }
 
-__attribute__ ((noinline))
+__noinline
 u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
 {
 	a += initval;
@@ -96,7 +96,7 @@ u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
 	return c;
 }
 
-__attribute__ ((noinline))
+__noinline
 u32 jhash_2words(u32 a, u32 b, u32 initval)
 {
 	return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
@@ -213,7 +213,7 @@ struct eth_hdr {
 	unsigned short eth_proto;
 };
 
-static inline __u64 calc_offset(bool is_ipv6, bool is_icmp)
+static __noinline __u64 calc_offset(bool is_ipv6, bool is_icmp)
 {
 	__u64 off = sizeof(struct eth_hdr);
 	if (is_ipv6) {
@@ -797,8 +797,8 @@ static int process_packet(void *data, __u64 off, void *data_end,
 	return XDP_DROP;
 }
 
-__attribute__ ((section("xdp-test"), used))
-int balancer_ingress(struct xdp_md *ctx)
+SEC("xdp-test-v4")
+int balancer_ingress_v4(struct xdp_md *ctx)
 {
 	void *data = (void *)(long)ctx->data;
 	void *data_end = (void *)(long)ctx->data_end;
@@ -812,11 +812,27 @@ int balancer_ingress(struct xdp_md *ctx)
 	eth_proto = bpf_ntohs(eth->eth_proto);
 	if (eth_proto == ETH_P_IP)
 		return process_packet(data, nh_off, data_end, 0, ctx);
-	else if (eth_proto == ETH_P_IPV6)
+	else
+		return XDP_DROP;
+}
+
+SEC("xdp-test-v6")
+int balancer_ingress_v6(struct xdp_md *ctx)
+{
+	void *data = (void *)(long)ctx->data;
+	void *data_end = (void *)(long)ctx->data_end;
+	struct eth_hdr *eth = data;
+	__u32 eth_proto;
+	__u32 nh_off;
+
+	nh_off = sizeof(struct eth_hdr);
+	if (data + nh_off > data_end)
+		return XDP_DROP;
+	eth_proto = bpf_ntohs(eth->eth_proto);
+	if (eth_proto == ETH_P_IPV6)
 		return process_packet(data, nh_off, data_end, 1, ctx);
 	else
 		return XDP_DROP;
 }
 
-char _license[] __attribute__ ((section("license"), used)) = "GPL";
-int _version __attribute__ ((section("version"), used)) = 1;
+char _license[] SEC("license") = "GPL";