bpf: selftests: Add test case for BPF_F_PROG_NO_CHARGE

Test case to check if BPF_F_PROG_NO_CHARGE valid.
The result as follows,
 $ ./test_progs
 ...
 #103 no_charge:OK
 ...

Signed-off-by: Yafang Shao <[email protected]>

Author: laoar

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

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <linux/bpf.h>
+#include <sys/syscall.h>
+
+#include "test_progs.h"
+
+#define BPF_ALU64_IMM(OP, DST, IMM)					\
+	((struct bpf_insn) {							\
+		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,	\
+		.dst_reg = DST,								\
+		.src_reg = 0,								\
+		.off   = 0,									\
+		.imm   = IMM })
+
+#define BPF_EXIT_INSN()					\
+	((struct bpf_insn) {				\
+		.code  = BPF_JMP | BPF_EXIT,	\
+		.dst_reg = 0,					\
+		.src_reg = 0,					\
+		.off   = 0,						\
+		.imm   = 0 })
+
+void test_no_charge(void)
+{
+	struct bpf_insn prog[] = {
+		BPF_ALU64_IMM(BPF_MOV, BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	};
+	union bpf_attr attr;
+	int duration = 0;
+	int fd;
+
+	bzero(&attr, sizeof(attr));
+	attr.prog_type = BPF_PROG_TYPE_SCHED_CLS;
+	attr.insn_cnt = 2;
+	attr.insns = (__u64)prog;
+	attr.license = (__u64)("GPL");
+	attr.prog_flags |= BPF_F_PROG_NO_CHARGE;
+
+	fd = syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
+	CHECK(fd < 0 && fd != -EPERM, "no_charge", "error: %s\n",
+			strerror(errno));
+
+	if (fd > 0)
+		close(fd);
+}