selftests/bpf: verifier/xdp.c converted to inline assembly

Test verifier/xdp.c automatically converted to use inline assembly.

Signed-off-by: Eduard Zingerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

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

···
 #include "verifier_value_or_null.skel.h"
 #include "verifier_var_off.skel.h"
 #include "verifier_xadd.skel.h"
+#include "verifier_xdp.skel.h"
 
 __maybe_unused
 static void run_tests_aux(const char *skel_name, skel_elf_bytes_fn elf_bytes_factory)
···
 void test_verifier_value_or_null(void)        { RUN(verifier_value_or_null); }
 void test_verifier_var_off(void)              { RUN(verifier_var_off); }
 void test_verifier_xadd(void)                 { RUN(verifier_xadd); }
+void test_verifier_xdp(void)                  { RUN(verifier_xdp); }

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

···
+// SPDX-License-Identifier: GPL-2.0
+/* Converted from tools/testing/selftests/bpf/verifier/xdp.c */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+SEC("xdp")
+__description("XDP, using ifindex from netdev")
+__success __retval(1)
+__naked void xdp_using_ifindex_from_netdev(void)
+{
+	asm volatile ("					\
+	r0 = 0;						\
+	r2 = *(u32*)(r1 + %[xdp_md_ingress_ifindex]);	\
+	if r2 < 1 goto l0_%=;				\
+	r0 = 1;						\
+l0_%=:	exit;						\
+"	:
+	: __imm_const(xdp_md_ingress_ifindex, offsetof(struct xdp_md, ingress_ifindex))
+	: __clobber_all);
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/verifier/xdp.c

···
-{
-	"XDP, using ifindex from netdev",
-	.insns = {
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
-		    offsetof(struct xdp_md, ingress_ifindex)),
-	BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 1, 1),
-	BPF_MOV64_IMM(BPF_REG_0, 1),
-	BPF_EXIT_INSN(),
-	},
-	.result = ACCEPT,
-	.prog_type = BPF_PROG_TYPE_XDP,
-	.retval = 1,
-},