/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2023-2025 Ruslan Bukin <br@bsdpad.com>
 *
 * This work was supported by Innovate UK project 105694, "Digital Security
 * by Design (DSbD) Technology Platform Prototype".
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/refcount.h>
#include <sys/rwlock.h>
#include <sys/hwt.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vm_pageout.h>
#include <vm/vm_phys.h>

#include <dev/hwt/hwt_hook.h>
#include <dev/hwt/hwt_context.h>
#include <dev/hwt/hwt_contexthash.h>
#include <dev/hwt/hwt_config.h>
#include <dev/hwt/hwt_thread.h>
#include <dev/hwt/hwt_owner.h>
#include <dev/hwt/hwt_ownerhash.h>
#include <dev/hwt/hwt_backend.h>
#include <dev/hwt/hwt_vm.h>
#include <dev/hwt/hwt_record.h>

#define HWT_THREAD_DEBUG
#undef  HWT_THREAD_DEBUG

#ifdef  HWT_THREAD_DEBUG
#define dprintf(fmt, ...)       printf(fmt, ##__VA_ARGS__)
#else
#define dprintf(fmt, ...)
#endif

static MALLOC_DEFINE(M_HWT_THREAD, "hwt_thread", "Hardware Trace");

struct hwt_thread *
hwt_thread_first(struct hwt_context *ctx)
{
        struct hwt_thread *thr;

        HWT_CTX_ASSERT_LOCKED(ctx);

        thr = TAILQ_FIRST(&ctx->threads);

        KASSERT(thr != NULL, ("thr is NULL"));

        return (thr);
}

/*
 * To use by hwt_switch_in/out() only.
 */
struct hwt_thread *
hwt_thread_lookup(struct hwt_context *ctx, struct thread *td)
{
        struct hwt_thread *thr;

        /* Caller of this func holds ctx refcnt right here. */

        HWT_CTX_LOCK(ctx);
        TAILQ_FOREACH(thr, &ctx->threads, next) {
                if (thr->td == td) {
                        HWT_CTX_UNLOCK(ctx);
                        return (thr);
                }
        }
        HWT_CTX_UNLOCK(ctx);

        /*
         * We are here because the hook on thread creation failed to allocate
         * a thread.
         */

        return (NULL);
}

int
hwt_thread_alloc(struct hwt_thread **thr0, char *path, size_t bufsize,
    int kva_req)
{
        struct hwt_thread *thr;
        struct hwt_vm *vm;
        int error;

        error = hwt_vm_alloc(bufsize, kva_req, path, &vm);
        if (error)
                return (error);

        thr = malloc(sizeof(struct hwt_thread), M_HWT_THREAD,
            M_WAITOK | M_ZERO);
        thr->vm = vm;

        mtx_init(&thr->mtx, "thr", NULL, MTX_DEF);

        refcount_init(&thr->refcnt, 1);

        vm->thr = thr;

        *thr0 = thr;

        return (0);
}

void
hwt_thread_free(struct hwt_thread *thr)
{

        hwt_vm_free(thr->vm);
        /* Free private backend data, if any. */
        if (thr->private != NULL)
                hwt_backend_thread_free(thr);
        free(thr, M_HWT_THREAD);
}

/*
 * Inserts a new thread and a thread creation record into the
 * context notifies userspace about the newly created thread.
 */
void
hwt_thread_insert(struct hwt_context *ctx, struct hwt_thread *thr,
    struct hwt_record_entry *entry)
{

        HWT_CTX_ASSERT_LOCKED(ctx);
        TAILQ_INSERT_TAIL(&ctx->threads, thr, next);
        TAILQ_INSERT_TAIL(&ctx->records, entry, next);
}