selftests/bpf: Change functions definitions to support GCC

The test_xdp_noinline.c contains 2 functions that use more then 5
arguments. This patch collapses the 2 last arguments in an array.
Also in GCC and ipa_sra optimization increases the number of arguments
used in function encap_v4. This pass disables the optimization for that
particular file.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240507122220.207820-3-cupertino.miranda@oracle.com

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

@@ -318,6 +318,14 @@ bool encap_v6(struct xdp_md *xdp, struct ctl_value *cval,
 	return true;
 }
 
+#ifndef __clang__
+#pragma GCC push_options
+/* GCC optimization collapses functions and increases the number of arguments
+ * beyond the compatible amount supported by BPF.
+ */
+#pragma GCC optimize("-fno-ipa-sra")
+#endif
+
 static __attribute__ ((noinline))
 bool encap_v4(struct xdp_md *xdp, struct ctl_value *cval,
 	      struct packet_description *pckt,
@@ -372,6 +380,10 @@ bool encap_v4(struct xdp_md *xdp, struct ctl_value *cval,
 	return true;
 }
 
+#ifndef __clang__
+#pragma GCC pop_options
+#endif
+
 static __attribute__ ((noinline))
 int swap_mac_and_send(void *data, void *data_end)
 {
@@ -588,12 +600,13 @@ static void connection_table_lookup(struct real_definition **real,
 __attribute__ ((noinline))
 static int process_l3_headers_v6(struct packet_description *pckt,
 				 __u8 *protocol, __u64 off,
-				 __u16 *pkt_bytes, void *data,
-				 void *data_end)
+				 __u16 *pkt_bytes, void *extra_args[2])
 {
 	struct ipv6hdr *ip6h;
 	__u64 iph_len;
 	int action;
+	void *data = extra_args[0];
+	void *data_end = extra_args[1];
 
 	ip6h = data + off;
 	if (ip6h + 1 > data_end)
@@ -619,11 +632,12 @@ static int process_l3_headers_v6(struct packet_description *pckt,
 __attribute__ ((noinline))
 static int process_l3_headers_v4(struct packet_description *pckt,
 				 __u8 *protocol, __u64 off,
-				 __u16 *pkt_bytes, void *data,
-				 void *data_end)
+				 __u16 *pkt_bytes, void *extra_args[2])
 {
 	struct iphdr *iph;
 	int action;
+	void *data = extra_args[0];
+	void *data_end = extra_args[1];
 
 	iph = data + off;
 	if (iph + 1 > data_end)
@@ -666,13 +680,14 @@ static int process_packet(void *data, __u64 off, void *data_end,
 	__u8 protocol;
 	__u32 vip_num;
 	int action;
+	void *extra_args[2] = { data, data_end };
 
 	if (is_ipv6)
 		action = process_l3_headers_v6(&pckt, &protocol, off,
-					       &pkt_bytes, data, data_end);
+					       &pkt_bytes, extra_args);
 	else
 		action = process_l3_headers_v4(&pckt, &protocol, off,
-					       &pkt_bytes, data, data_end);
+					       &pkt_bytes, extra_args);
 	if (action >= 0)
 		return action;
 	protocol = pckt.flow.proto;