selftests/bpf: Add tests for atomics in bpf_arena.

Add selftests for atomic instructions in bpf_arena.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240405231134.17274-2-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

tools/testing/selftests/bpf/DENYLIST.aarch64

@@ -10,3 +10,4 @@ fill_link_info/kprobe_multi_link_info            # bpf_program__attach_kprobe_mu
 fill_link_info/kretprobe_multi_link_info         # bpf_program__attach_kprobe_multi_opts unexpected error: -95
 fill_link_info/kprobe_multi_invalid_ubuff        # bpf_program__attach_kprobe_multi_opts unexpected error: -95
 missed/kprobe_recursion                          # missed_kprobe_recursion__attach unexpected error: -95 (errno 95)
+arena_atomics

tools/testing/selftests/bpf/DENYLIST.s390x

@@ -6,3 +6,4 @@ stacktrace_build_id                      # compare_map_keys stackid_hmap vs. sta
 verifier_iterating_callbacks
 verifier_arena                           # JIT does not support arena
 arena_htab                               # JIT does not support arena
+arena_atomics

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

@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#include <test_progs.h>
+#include "arena_atomics.skel.h"
+
+static void test_add(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.add);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->add64_value, 3, "add64_value");
+	ASSERT_EQ(skel->arena->add64_result, 1, "add64_result");
+
+	ASSERT_EQ(skel->arena->add32_value, 3, "add32_value");
+	ASSERT_EQ(skel->arena->add32_result, 1, "add32_result");
+
+	ASSERT_EQ(skel->arena->add_stack_value_copy, 3, "add_stack_value");
+	ASSERT_EQ(skel->arena->add_stack_result, 1, "add_stack_result");
+
+	ASSERT_EQ(skel->arena->add_noreturn_value, 3, "add_noreturn_value");
+}
+
+static void test_sub(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.sub);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->sub64_value, -1, "sub64_value");
+	ASSERT_EQ(skel->arena->sub64_result, 1, "sub64_result");
+
+	ASSERT_EQ(skel->arena->sub32_value, -1, "sub32_value");
+	ASSERT_EQ(skel->arena->sub32_result, 1, "sub32_result");
+
+	ASSERT_EQ(skel->arena->sub_stack_value_copy, -1, "sub_stack_value");
+	ASSERT_EQ(skel->arena->sub_stack_result, 1, "sub_stack_result");
+
+	ASSERT_EQ(skel->arena->sub_noreturn_value, -1, "sub_noreturn_value");
+}
+
+static void test_and(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.and);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->and64_value, 0x010ull << 32, "and64_value");
+	ASSERT_EQ(skel->arena->and32_value, 0x010, "and32_value");
+}
+
+static void test_or(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.or);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->or64_value, 0x111ull << 32, "or64_value");
+	ASSERT_EQ(skel->arena->or32_value, 0x111, "or32_value");
+}
+
+static void test_xor(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.xor);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->xor64_value, 0x101ull << 32, "xor64_value");
+	ASSERT_EQ(skel->arena->xor32_value, 0x101, "xor32_value");
+}
+
+static void test_cmpxchg(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.cmpxchg);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->cmpxchg64_value, 2, "cmpxchg64_value");
+	ASSERT_EQ(skel->arena->cmpxchg64_result_fail, 1, "cmpxchg_result_fail");
+	ASSERT_EQ(skel->arena->cmpxchg64_result_succeed, 1, "cmpxchg_result_succeed");
+
+	ASSERT_EQ(skel->arena->cmpxchg32_value, 2, "lcmpxchg32_value");
+	ASSERT_EQ(skel->arena->cmpxchg32_result_fail, 1, "cmpxchg_result_fail");
+	ASSERT_EQ(skel->arena->cmpxchg32_result_succeed, 1, "cmpxchg_result_succeed");
+}
+
+static void test_xchg(struct arena_atomics *skel)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts);
+	int err, prog_fd;
+
+	/* No need to attach it, just run it directly */
+	prog_fd = bpf_program__fd(skel->progs.xchg);
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "test_run_opts err"))
+		return;
+	if (!ASSERT_OK(topts.retval, "test_run_opts retval"))
+		return;
+
+	ASSERT_EQ(skel->arena->xchg64_value, 2, "xchg64_value");
+	ASSERT_EQ(skel->arena->xchg64_result, 1, "xchg64_result");
+
+	ASSERT_EQ(skel->arena->xchg32_value, 2, "xchg32_value");
+	ASSERT_EQ(skel->arena->xchg32_result, 1, "xchg32_result");
+}
+
+void test_arena_atomics(void)
+{
+	struct arena_atomics *skel;
+	int err;
+
+	skel = arena_atomics__open();
+	if (!ASSERT_OK_PTR(skel, "arena atomics skeleton open"))
+		return;
+
+	if (skel->data->skip_tests) {
+		printf("%s:SKIP:no ENABLE_ATOMICS_TESTS or no addr_space_cast support in clang",
+		       __func__);
+		test__skip();
+		goto cleanup;
+	}
+	err = arena_atomics__load(skel);
+	if (!ASSERT_OK(err, "arena atomics skeleton load"))
+		return;
+	skel->bss->pid = getpid();
+
+	if (test__start_subtest("add"))
+		test_add(skel);
+	if (test__start_subtest("sub"))
+		test_sub(skel);
+	if (test__start_subtest("and"))
+		test_and(skel);
+	if (test__start_subtest("or"))
+		test_or(skel);
+	if (test__start_subtest("xor"))
+		test_xor(skel);
+	if (test__start_subtest("cmpxchg"))
+		test_cmpxchg(skel);
+	if (test__start_subtest("xchg"))
+		test_xchg(skel);
+
+cleanup:
+	arena_atomics__destroy(skel);
+}

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

@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <stdbool.h>
+#include "bpf_arena_common.h"
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARENA);
+	__uint(map_flags, BPF_F_MMAPABLE);
+	__uint(max_entries, 10); /* number of pages */
+#ifdef __TARGET_ARCH_arm64
+	__ulong(map_extra, 0x1ull << 32); /* start of mmap() region */
+#else
+	__ulong(map_extra, 0x1ull << 44); /* start of mmap() region */
+#endif
+} arena SEC(".maps");
+
+#if defined(ENABLE_ATOMICS_TESTS) && defined(__BPF_FEATURE_ADDR_SPACE_CAST)
+bool skip_tests __attribute((__section__(".data"))) = false;
+#else
+bool skip_tests = true;
+#endif
+
+__u32 pid = 0;
+
+#undef __arena
+#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
+#define __arena __attribute__((address_space(1)))
+#else
+#define __arena SEC(".addr_space.1")
+#endif
+
+__u64 __arena add64_value = 1;
+__u64 __arena add64_result = 0;
+__u32 __arena add32_value = 1;
+__u32 __arena add32_result = 0;
+__u64 __arena add_stack_value_copy = 0;
+__u64 __arena add_stack_result = 0;
+__u64 __arena add_noreturn_value = 1;
+
+SEC("raw_tp/sys_enter")
+int add(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+#ifdef ENABLE_ATOMICS_TESTS
+	__u64 add_stack_value = 1;
+
+	add64_result = __sync_fetch_and_add(&add64_value, 2);
+	add32_result = __sync_fetch_and_add(&add32_value, 2);
+	add_stack_result = __sync_fetch_and_add(&add_stack_value, 2);
+	add_stack_value_copy = add_stack_value;
+	__sync_fetch_and_add(&add_noreturn_value, 2);
+#endif
+
+	return 0;
+}
+
+__s64 __arena sub64_value = 1;
+__s64 __arena sub64_result = 0;
+__s32 __arena sub32_value = 1;
+__s32 __arena sub32_result = 0;
+__s64 __arena sub_stack_value_copy = 0;
+__s64 __arena sub_stack_result = 0;
+__s64 __arena sub_noreturn_value = 1;
+
+SEC("raw_tp/sys_enter")
+int sub(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+#ifdef ENABLE_ATOMICS_TESTS
+	__u64 sub_stack_value = 1;
+
+	sub64_result = __sync_fetch_and_sub(&sub64_value, 2);
+	sub32_result = __sync_fetch_and_sub(&sub32_value, 2);
+	sub_stack_result = __sync_fetch_and_sub(&sub_stack_value, 2);
+	sub_stack_value_copy = sub_stack_value;
+	__sync_fetch_and_sub(&sub_noreturn_value, 2);
+#endif
+
+	return 0;
+}
+
+__u64 __arena and64_value = (0x110ull << 32);
+__u32 __arena and32_value = 0x110;
+
+SEC("raw_tp/sys_enter")
+int and(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+#ifdef ENABLE_ATOMICS_TESTS
+
+	__sync_fetch_and_and(&and64_value, 0x011ull << 32);
+	__sync_fetch_and_and(&and32_value, 0x011);
+#endif
+
+	return 0;
+}
+
+__u32 __arena or32_value = 0x110;
+__u64 __arena or64_value = (0x110ull << 32);
+
+SEC("raw_tp/sys_enter")
+int or(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+#ifdef ENABLE_ATOMICS_TESTS
+	__sync_fetch_and_or(&or64_value, 0x011ull << 32);
+	__sync_fetch_and_or(&or32_value, 0x011);
+#endif
+
+	return 0;
+}
+
+__u64 __arena xor64_value = (0x110ull << 32);
+__u32 __arena xor32_value = 0x110;
+
+SEC("raw_tp/sys_enter")
+int xor(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+#ifdef ENABLE_ATOMICS_TESTS
+	__sync_fetch_and_xor(&xor64_value, 0x011ull << 32);
+	__sync_fetch_and_xor(&xor32_value, 0x011);
+#endif
+
+	return 0;
+}
+
+__u32 __arena cmpxchg32_value = 1;
+__u32 __arena cmpxchg32_result_fail = 0;
+__u32 __arena cmpxchg32_result_succeed = 0;
+__u64 __arena cmpxchg64_value = 1;
+__u64 __arena cmpxchg64_result_fail = 0;
+__u64 __arena cmpxchg64_result_succeed = 0;
+
+SEC("raw_tp/sys_enter")
+int cmpxchg(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+#ifdef ENABLE_ATOMICS_TESTS
+	cmpxchg64_result_fail = __sync_val_compare_and_swap(&cmpxchg64_value, 0, 3);
+	cmpxchg64_result_succeed = __sync_val_compare_and_swap(&cmpxchg64_value, 1, 2);
+
+	cmpxchg32_result_fail = __sync_val_compare_and_swap(&cmpxchg32_value, 0, 3);
+	cmpxchg32_result_succeed = __sync_val_compare_and_swap(&cmpxchg32_value, 1, 2);
+#endif
+
+	return 0;
+}
+
+__u64 __arena xchg64_value = 1;
+__u64 __arena xchg64_result = 0;
+__u32 __arena xchg32_value = 1;
+__u32 __arena xchg32_result = 0;
+
+SEC("raw_tp/sys_enter")
+int xchg(const void *ctx)
+{
+	if (pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+#ifdef ENABLE_ATOMICS_TESTS
+	__u64 val64 = 2;
+	__u32 val32 = 2;
+
+	xchg64_result = __sync_lock_test_and_set(&xchg64_value, val64);
+	xchg32_result = __sync_lock_test_and_set(&xchg32_value, val32);
+#endif
+
+	return 0;
+}