selftests/bpf: Add bpf_arena_htab test.

bpf_arena_htab.h - hash table implemented as bpf program

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240308010812.89848-15-alexei.starovoitov@gmail.com

1 files changed, 88 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/arena_htab.c b/tools/testing/selftests/bpf/prog_tests/arena_htab.c
new file mode 100644
index 000000000000..0766702de846
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/arena_htab.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#include <test_progs.h>
+#include <sys/mman.h>
+#include <network_helpers.h>
+
+#include "arena_htab_asm.skel.h"
+#include "arena_htab.skel.h"
+
+#define PAGE_SIZE 4096
+
+#include "bpf_arena_htab.h"
+
+static void test_arena_htab_common(struct htab *htab)
+{
+	int i;
+
+	printf("htab %p buckets %p n_buckets %d\n", htab, htab->buckets, htab->n_buckets);
+	ASSERT_OK_PTR(htab->buckets, "htab->buckets shouldn't be NULL");
+	for (i = 0; htab->buckets && i < 16; i += 4) {
+		/*
+		 * Walk htab buckets and link lists since all pointers are correct,
+		 * though they were written by bpf program.
+		 */
+		int val = htab_lookup_elem(htab, i);
+
+		ASSERT_EQ(i, val, "key == value");
+	}
+}
+
+static void test_arena_htab_llvm(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts);
+	struct arena_htab *skel;
+	struct htab *htab;
+	size_t arena_sz;
+	void *area;
+	int ret;
+
+	skel = arena_htab__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "arena_htab__open_and_load"))
+		return;
+
+	area = bpf_map__initial_value(skel->maps.arena, &arena_sz);
+	/* fault-in a page with pgoff == 0 as sanity check */
+	*(volatile int *)area = 0x55aa;
+
+	/* bpf prog will allocate more pages */
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.arena_htab_llvm), &opts);
+	ASSERT_OK(ret, "ret");
+	ASSERT_OK(opts.retval, "retval");
+	if (skel->bss->skip) {
+		printf("%s:SKIP:compiler doesn't support arena_cast\n", __func__);
+		test__skip();
+		goto out;
+	}
+	htab = skel->bss->htab_for_user;
+	test_arena_htab_common(htab);
+out:
+	arena_htab__destroy(skel);
+}
+
+static void test_arena_htab_asm(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts);
+	struct arena_htab_asm *skel;
+	struct htab *htab;
+	int ret;
+
+	skel = arena_htab_asm__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "arena_htab_asm__open_and_load"))
+		return;
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.arena_htab_asm), &opts);
+	ASSERT_OK(ret, "ret");
+	ASSERT_OK(opts.retval, "retval");
+	htab = skel->bss->htab_for_user;
+	test_arena_htab_common(htab);
+	arena_htab_asm__destroy(skel);
+}
+
+void test_arena_htab(void)
+{
+	if (test__start_subtest("arena_htab_llvm"))
+		test_arena_htab_llvm();
+	if (test__start_subtest("arena_htab_asm"))
+		test_arena_htab_asm();
+}