/*-
 * 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.
 */

#ifndef _DEV_HWT_HWT_BACKEND_H_
#define _DEV_HWT_HWT_BACKEND_H_

struct hwt_backend_ops {
        int (*hwt_backend_init)(struct hwt_context *);
        int (*hwt_backend_deinit)(struct hwt_context *);
        int (*hwt_backend_configure)(struct hwt_context *, int cpu_id,
            int thread_id);
        int (*hwt_backend_svc_buf)(struct hwt_context *, void *data,
            size_t data_size, int data_version);
        void (*hwt_backend_enable)(struct hwt_context *, int cpu_id);
        void (*hwt_backend_disable)(struct hwt_context *, int cpu_id);
        int (*hwt_backend_read)(struct hwt_vm *, int *ident,
            vm_offset_t *offset, uint64_t *data);
        void (*hwt_backend_stop)(struct hwt_context *);
        /* For backends that are tied to local CPU registers */
        int (*hwt_backend_enable_smp)(struct hwt_context *);
        int (*hwt_backend_disable_smp)(struct hwt_context *);
        /* Allocation and initialization of backend-specific thread data. */
        int (*hwt_backend_thread_alloc)(struct hwt_thread *);
        void (*hwt_backend_thread_free)(struct hwt_thread *);
        /* Debugging only. */
        void (*hwt_backend_dump)(int cpu_id);
};

struct hwt_backend {
        const char                      *name;
        struct hwt_backend_ops          *ops;
        /* buffers require kernel virtual addresses */
        bool                            kva_req;
};

int hwt_backend_init(struct hwt_context *ctx);
void hwt_backend_deinit(struct hwt_context *ctx);
int hwt_backend_configure(struct hwt_context *ctx, int cpu_id, int thread_id);
void hwt_backend_enable(struct hwt_context *ctx, int cpu_id);
void hwt_backend_disable(struct hwt_context *ctx, int cpu_id);
void hwt_backend_enable_smp(struct hwt_context *ctx);
void hwt_backend_disable_smp(struct hwt_context *ctx);
void hwt_backend_dump(struct hwt_context *ctx, int cpu_id);
int hwt_backend_read(struct hwt_context *ctx, struct hwt_vm *vm, int *ident,
    vm_offset_t *offset, uint64_t *data);
int hwt_backend_register(struct hwt_backend *);
int hwt_backend_unregister(struct hwt_backend *);
void hwt_backend_stop(struct hwt_context *);
int hwt_backend_svc_buf(struct hwt_context *ctx, void *data, size_t data_size,
    int data_version);
struct hwt_backend * hwt_backend_lookup(const char *name);
int hwt_backend_thread_alloc(struct hwt_context *ctx, struct hwt_thread *);
void hwt_backend_thread_free(struct hwt_thread *);

void hwt_backend_load(void);
void hwt_backend_unload(void);

#define HWT_BACKEND_LOCK()              mtx_lock(&hwt_backend_mtx)
#define HWT_BACKEND_UNLOCK()            mtx_unlock(&hwt_backend_mtx)

#endif /* !_DEV_HWT_HWT_BACKEND_H_ */