selftests/bpf: Add raw_tp_test_run

This test runs test_run for raw_tracepoint program. The test covers ctx
input, retval output, and running on correct cpu.
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200925205432.1777-4-songliubraving@fb.com

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

+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019 Facebook */
+#include <test_progs.h>
+#include <linux/bpf.h>
+#include "bpf/libbpf_internal.h"
+#include "test_raw_tp_test_run.skel.h"
+
+static int duration;
+
+void test_raw_tp_test_run(void)
+{
+	struct bpf_prog_test_run_attr test_attr = {};
+	int comm_fd = -1, err, nr_online, i, prog_fd;
+	__u64 args[2] = {0x1234ULL, 0x5678ULL};
+	int expected_retval = 0x1234 + 0x5678;
+	struct test_raw_tp_test_run *skel;
+	char buf[] = "new_name";
+	bool *online = NULL;
+	DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
+			    .ctx_in = args,
+			    .ctx_size_in = sizeof(args),
+			    .flags = BPF_F_TEST_RUN_ON_CPU,
+		);
+
+	err = parse_cpu_mask_file("/sys/devices/system/cpu/online", &online,
+				  &nr_online);
+	if (CHECK(err, "parse_cpu_mask_file", "err %d\n", err))
+		return;
+
+	skel = test_raw_tp_test_run__open_and_load();
+	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+		goto cleanup;
+
+	err = test_raw_tp_test_run__attach(skel);
+	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+		goto cleanup;
+
+	comm_fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
+	if (CHECK(comm_fd < 0, "open /proc/self/comm", "err %d\n", errno))
+		goto cleanup;
+
+	err = write(comm_fd, buf, sizeof(buf));
+	CHECK(err < 0, "task rename", "err %d", errno);
+
+	CHECK(skel->bss->count == 0, "check_count", "didn't increase\n");
+	CHECK(skel->data->on_cpu != 0xffffffff, "check_on_cpu", "got wrong value\n");
+
+	prog_fd = bpf_program__fd(skel->progs.rename);
+	test_attr.prog_fd = prog_fd;
+	test_attr.ctx_in = args;
+	test_attr.ctx_size_in = sizeof(__u64);
+
+	err = bpf_prog_test_run_xattr(&test_attr);
+	CHECK(err == 0, "test_run", "should fail for too small ctx\n");
+
+	test_attr.ctx_size_in = sizeof(args);
+	err = bpf_prog_test_run_xattr(&test_attr);
+	CHECK(err < 0, "test_run", "err %d\n", errno);
+	CHECK(test_attr.retval != expected_retval, "check_retval",
+	      "expect 0x%x, got 0x%x\n", expected_retval, test_attr.retval);
+
+	for (i = 0; i < nr_online; i++) {
+		if (!online[i])
+			continue;
+
+		opts.cpu = i;
+		opts.retval = 0;
+		err = bpf_prog_test_run_opts(prog_fd, &opts);
+		CHECK(err < 0, "test_run_opts", "err %d\n", errno);
+		CHECK(skel->data->on_cpu != i, "check_on_cpu",
+		      "expect %d got %d\n", i, skel->data->on_cpu);
+		CHECK(opts.retval != expected_retval,
+		      "check_retval", "expect 0x%x, got 0x%x\n",
+		      expected_retval, opts.retval);
+	}
+
+	/* invalid cpu ID should fail with ENXIO */
+	opts.cpu = 0xffffffff;
+	err = bpf_prog_test_run_opts(prog_fd, &opts);
+	CHECK(err != -1 || errno != ENXIO,
+	      "test_run_opts_fail",
+	      "should failed with ENXIO\n");
+
+	/* non-zero cpu w/o BPF_F_TEST_RUN_ON_CPU should fail with EINVAL */
+	opts.cpu = 1;
+	opts.flags = 0;
+	err = bpf_prog_test_run_opts(prog_fd, &opts);
+	CHECK(err != -1 || errno != EINVAL,
+	      "test_run_opts_fail",
+	      "should failed with EINVAL\n");
+
+cleanup:
+	close(comm_fd);
+	test_raw_tp_test_run__destroy(skel);
+	free(online);
+}

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

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+__u32 count = 0;
+__u32 on_cpu = 0xffffffff;
+
+SEC("raw_tp/task_rename")
+int BPF_PROG(rename, struct task_struct *task, char *comm)
+{
+
+	count++;
+	if ((__u64) task == 0x1234ULL && (__u64) comm == 0x5678ULL) {
+		on_cpu = bpf_get_smp_processor_id();
+		return (int)task + (int)comm;
+	}
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";