selftests/bpf: Add unit tests for new gotol insn

Add unit tests for gotol insn.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011329.3721881-1-yonghong.song@linux.devSigned-off-by: Alexei Starovoitov <ast@kernel.org>

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

@@ -25,6 +25,7 @@
 #include "verifier_direct_stack_access_wraparound.skel.h"
 #include "verifier_div0.skel.h"
 #include "verifier_div_overflow.skel.h"
+#include "verifier_gotol.skel.h"
 #include "verifier_helper_access_var_len.skel.h"
 #include "verifier_helper_packet_access.skel.h"
 #include "verifier_helper_restricted.skel.h"
@@ -131,6 +132,7 @@ void test_verifier_direct_packet_access(void) { RUN(verifier_direct_packet_acces
 void test_verifier_direct_stack_access_wraparound(void) { RUN(verifier_direct_stack_access_wraparound); }
 void test_verifier_div0(void)                 { RUN(verifier_div0); }
 void test_verifier_div_overflow(void)         { RUN(verifier_div_overflow); }
+void test_verifier_gotol(void)                { RUN(verifier_gotol); }
 void test_verifier_helper_access_var_len(void) { RUN(verifier_helper_access_var_len); }
 void test_verifier_helper_packet_access(void) { RUN(verifier_helper_packet_access); }
 void test_verifier_helper_restricted(void)    { RUN(verifier_helper_restricted); }

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

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+#if defined(__TARGET_ARCH_x86) && __clang_major__ >= 18
+
+SEC("socket")
+__description("gotol, small_imm")
+__success __success_unpriv __retval(1)
+__naked void gotol_small_imm(void)
+{
+	asm volatile ("					\
+	call %[bpf_ktime_get_ns];			\
+	if r0 == 0 goto l0_%=;				\
+	gotol l1_%=;					\
+l2_%=:							\
+	gotol l3_%=;					\
+l1_%=:							\
+	r0 = 1;						\
+	gotol l2_%=;					\
+l0_%=:							\
+	r0 = 2;						\
+l3_%=:							\
+	exit;						\
+"	:
+	: __imm(bpf_ktime_get_ns)
+	: __clobber_all);
+}
+
+#else
+
+SEC("socket")
+__description("cpuv4 is not supported by compiler or jit, use a dummy test")
+__success
+int dummy_test(void)
+{
+	return 0;
+}
+
+#endif
+
+char _license[] SEC("license") = "GPL";