bpf: allow to specify log level and reduce it for test_verifier

For the test_verifier case, it's quite hard to parse log level 2 to
figure out what's causing an issue when used to log level 1. We do
want to use bpf_verify_program() in order to simulate some of the
tests with strict alignment. So just add an argument to pass the level
and put it to 1 for test_verifier.

Signed-off-by: Daniel Borkmann <[e-mail]>
Acked-by: Alexei Starovoitov <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

tools/lib/bpf/bpf.c

···
 int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
 		       size_t insns_cnt, int strict_alignment,
 		       const char *license, __u32 kern_version,
-		       char *log_buf, size_t log_buf_sz)
+		       char *log_buf, size_t log_buf_sz, int log_level)
 {
 	union bpf_attr attr;
 
···
 	attr.license = ptr_to_u64(license);
 	attr.log_buf = ptr_to_u64(log_buf);
 	attr.log_size = log_buf_sz;
-	attr.log_level = 2;
+	attr.log_level = log_level;
 	log_buf[0] = 0;
 	attr.kern_version = kern_version;
 	attr.prog_flags = strict_alignment ? BPF_F_STRICT_ALIGNMENT : 0;

tools/lib/bpf/bpf.h

···
 int bpf_verify_program(enum bpf_prog_type type, const struct bpf_insn *insns,
 		       size_t insns_cnt, int strict_alignment,
 		       const char *license, __u32 kern_version,
-		       char *log_buf, size_t log_buf_sz);
+		       char *log_buf, size_t log_buf_sz, int log_level);
 
 int bpf_map_update_elem(int fd, const void *key, const void *value,
 			__u64 flags);

tools/testing/selftests/bpf/test_align.c

···
 	prog_len = probe_filter_length(prog);
 	fd_prog = bpf_verify_program(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER,
 				     prog, prog_len, 1, "GPL", 0,
-				     bpf_vlog, sizeof(bpf_vlog));
+				     bpf_vlog, sizeof(bpf_vlog), 2);
 	if (fd_prog < 0) {
 		printf("Failed to load program.\n");
 		printf("%s", bpf_vlog);

tools/testing/selftests/bpf/test_verifier.c

···
 
 	fd_prog = bpf_verify_program(prog_type ? : BPF_PROG_TYPE_SOCKET_FILTER,
 				     prog, prog_len, test->flags & F_LOAD_WITH_STRICT_ALIGNMENT,
-				     "GPL", 0, bpf_vlog, sizeof(bpf_vlog));
+				     "GPL", 0, bpf_vlog, sizeof(bpf_vlog), 1);
 
 	expected_ret = unpriv && test->result_unpriv != UNDEF ?
 		       test->result_unpriv : test->result;