// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */

#include <test_progs.h>
#include "pro_epilogue.skel.h"
#include "epilogue_tailcall.skel.h"
#include "pro_epilogue_goto_start.skel.h"
#include "epilogue_exit.skel.h"
#include "pro_epilogue_with_kfunc.skel.h"

struct st_ops_args {
        __u64 a;
};

static void test_tailcall(void)
{
        LIBBPF_OPTS(bpf_test_run_opts, topts);
        struct epilogue_tailcall *skel;
        struct st_ops_args args;
        int err, prog_fd;

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

        topts.ctx_in = &args;
        topts.ctx_size_in = sizeof(args);

        skel->links.epilogue_tailcall =
                bpf_map__attach_struct_ops(skel->maps.epilogue_tailcall);
        if (!ASSERT_OK_PTR(skel->links.epilogue_tailcall, "attach_struct_ops"))
                goto done;

        /* Both test_epilogue_tailcall and test_epilogue_subprog are
         * patched with epilogue. When syscall_epilogue_tailcall()
         * is run, test_epilogue_tailcall() is triggered.
         * It executes a tail call and control is transferred to
         * test_epilogue_subprog(). Only test_epilogue_subprog()
         * does args->a += 1, thus final args.a value of 10001
         * guarantees that only the epilogue of the
         * test_epilogue_subprog is executed.
         */
        memset(&args, 0, sizeof(args));
        prog_fd = bpf_program__fd(skel->progs.syscall_epilogue_tailcall);
        err = bpf_prog_test_run_opts(prog_fd, &topts);
        ASSERT_OK(err, "bpf_prog_test_run_opts");
        ASSERT_EQ(args.a, 10001, "args.a");
        ASSERT_EQ(topts.retval, 10001 * 2, "topts.retval");

done:
        epilogue_tailcall__destroy(skel);
}

void test_pro_epilogue(void)
{
        RUN_TESTS(pro_epilogue);
        RUN_TESTS(pro_epilogue_goto_start);
        RUN_TESTS(epilogue_exit);
        RUN_TESTS(pro_epilogue_with_kfunc);
        if (test__start_subtest("tailcall"))
                test_tailcall();
}