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

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Google */

#include <test_progs.h>
#include <bpf/libbpf.h>
#include <bpf/btf.h>
#include "test_ksyms_btf.skel.h"
#include "test_ksyms_btf_null_check.skel.h"
#include "test_ksyms_weak.skel.h"
#include "test_ksyms_weak.lskel.h"
#include "test_ksyms_btf_write_check.skel.h"

static int duration;

static void test_basic(void)
{
	__u64 runqueues_addr, bpf_prog_active_addr;
	__u32 this_rq_cpu;
	int this_bpf_prog_active;
	struct test_ksyms_btf *skel = NULL;
	struct test_ksyms_btf__data *data;
	int err;

	err = kallsyms_find("runqueues", &runqueues_addr);
	if (CHECK(err == -EINVAL, "kallsyms_fopen", "failed to open: %d\n", errno))
		return;
	if (CHECK(err == -ENOENT, "ksym_find", "symbol 'runqueues' not found\n"))
		return;

	err = kallsyms_find("bpf_prog_active", &bpf_prog_active_addr);
	if (CHECK(err == -EINVAL, "kallsyms_fopen", "failed to open: %d\n", errno))
		return;
	if (CHECK(err == -ENOENT, "ksym_find", "symbol 'bpf_prog_active' not found\n"))
		return;

	skel = test_ksyms_btf__open_and_load();
	if (CHECK(!skel, "skel_open", "failed to open and load skeleton\n"))
		goto cleanup;

	err = test_ksyms_btf__attach(skel);
	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
		goto cleanup;

	/* trigger tracepoint */
	usleep(1);

	data = skel->data;
	CHECK(data->out__runqueues_addr != runqueues_addr, "runqueues_addr",
	      "got %llu, exp %llu\n",
	      (unsigned long long)data->out__runqueues_addr,
	      (unsigned long long)runqueues_addr);
	CHECK(data->out__bpf_prog_active_addr != bpf_prog_active_addr, "bpf_prog_active_addr",
	      "got %llu, exp %llu\n",
	      (unsigned long long)data->out__bpf_prog_active_addr,
	      (unsigned long long)bpf_prog_active_addr);

	CHECK(data->out__rq_cpu == -1, "rq_cpu",
	      "got %u, exp != -1\n", data->out__rq_cpu);
	CHECK(data->out__bpf_prog_active < 0, "bpf_prog_active",
	      "got %d, exp >= 0\n", data->out__bpf_prog_active);
	CHECK(data->out__cpu_0_rq_cpu != 0, "cpu_rq(0)->cpu",
	      "got %u, exp 0\n", data->out__cpu_0_rq_cpu);

	this_rq_cpu = data->out__this_rq_cpu;
	CHECK(this_rq_cpu != data->out__rq_cpu, "this_rq_cpu",
	      "got %u, exp %u\n", this_rq_cpu, data->out__rq_cpu);

	this_bpf_prog_active = data->out__this_bpf_prog_active;
	CHECK(this_bpf_prog_active != data->out__bpf_prog_active, "this_bpf_prog_active",
	      "got %d, exp %d\n", this_bpf_prog_active,
	      data->out__bpf_prog_active);

cleanup:
	test_ksyms_btf__destroy(skel);
}

static void test_null_check(void)
{
	struct test_ksyms_btf_null_check *skel;

	skel = test_ksyms_btf_null_check__open_and_load();
	CHECK(skel, "skel_open", "unexpected load of a prog missing null check\n");

	test_ksyms_btf_null_check__destroy(skel);
}

static void test_weak_syms(void)
{
	struct test_ksyms_weak *skel;
	struct test_ksyms_weak__data *data;
	int err;

	skel = test_ksyms_weak__open_and_load();
	if (!ASSERT_OK_PTR(skel, "test_ksyms_weak__open_and_load"))
		return;

	err = test_ksyms_weak__attach(skel);
	if (!ASSERT_OK(err, "test_ksyms_weak__attach"))
		goto cleanup;

	/* trigger tracepoint */
	usleep(1);

	data = skel->data;
	ASSERT_EQ(data->out__existing_typed, 0, "existing typed ksym");
	ASSERT_NEQ(data->out__existing_typeless, -1, "existing typeless ksym");
	ASSERT_EQ(data->out__non_existent_typeless, 0, "nonexistent typeless ksym");
	ASSERT_EQ(data->out__non_existent_typed, 0, "nonexistent typed ksym");

cleanup:
	test_ksyms_weak__destroy(skel);
}

static void test_weak_syms_lskel(void)
{
	struct test_ksyms_weak_lskel *skel;
	struct test_ksyms_weak_lskel__data *data;
	int err;

	skel = test_ksyms_weak_lskel__open_and_load();
	if (!ASSERT_OK_PTR(skel, "test_ksyms_weak_lskel__open_and_load"))
		return;

	err = test_ksyms_weak_lskel__attach(skel);
	if (!ASSERT_OK(err, "test_ksyms_weak_lskel__attach"))
		goto cleanup;

	/* trigger tracepoint */
	usleep(1);

	data = skel->data;
	ASSERT_EQ(data->out__existing_typed, 0, "existing typed ksym");
	ASSERT_NEQ(data->out__existing_typeless, -1, "existing typeless ksym");
	ASSERT_EQ(data->out__non_existent_typeless, 0, "nonexistent typeless ksym");
	ASSERT_EQ(data->out__non_existent_typed, 0, "nonexistent typed ksym");

cleanup:
	test_ksyms_weak_lskel__destroy(skel);
}

static void test_write_check(bool test_handler1)
{
	struct test_ksyms_btf_write_check *skel;

	skel = test_ksyms_btf_write_check__open();
	if (!ASSERT_OK_PTR(skel, "test_ksyms_btf_write_check__open"))
		return;
	bpf_program__set_autoload(test_handler1 ? skel->progs.handler2 : skel->progs.handler1, false);
	ASSERT_ERR(test_ksyms_btf_write_check__load(skel),
		   "unexpected load of a prog writing to ksym memory\n");

	test_ksyms_btf_write_check__destroy(skel);
}

void test_ksyms_btf(void)
{
	int percpu_datasec;
	struct btf *btf;

	btf = libbpf_find_kernel_btf();
	if (!ASSERT_OK_PTR(btf, "btf_exists"))
		return;

	percpu_datasec = btf__find_by_name_kind(btf, ".data..percpu",
						BTF_KIND_DATASEC);
	btf__free(btf);
	if (percpu_datasec < 0) {
		printf("%s:SKIP:no PERCPU DATASEC in kernel btf\n",
		       __func__);
		test__skip();
		return;
	}

	if (test__start_subtest("basic"))
		test_basic();

	if (test__start_subtest("null_check"))
		test_null_check();

	if (test__start_subtest("weak_ksyms"))
		test_weak_syms();

	if (test__start_subtest("weak_ksyms_lskel"))
		test_weak_syms_lskel();

	if (test__start_subtest("write_check1"))
		test_write_check(true);

	if (test__start_subtest("write_check2"))
		test_write_check(false);
}