/* Copyright (c) 2017-2018 ARM Limited
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __MBED_HANDLE_MANAGER_H__
#define __MBED_HANDLE_MANAGER_H__
/* -------------------------------------- Includes ----------------------------------- */
#include "psa_defs.h"
#include <stdint.h>
/* -------------------------------- Handle Manager Module ---------------------------- */
/*
* The Handle Manager module generates and exposes a unique
* identifier (handle) per handle memory (handle_mem) it receives.
* You can use the exposed handle identifier to relate to the "registered"
* handle memory.
*
* You can:
* - Ask for a unique handle identifier for a given handle memory [`handle_create`].
* - Ask for a pointer to the handle memory corresponding to a
* handle identifier [`handle_get_mem`].
* - Remove a handle from the handle manager module [`handle_destroy`].
*
* Note:
* Handle generation is done exclusively.
* Once you have a handle, you can remove or get its memory non-exclusively.
* The assumption is that only one context is dealing with a handle after it is
* generated.
*/
/* --------------------------------- extern "C" wrapper ------------------------------ */
#ifdef __cplusplus
extern "C" {
#endif
/* ------------------------------------ Definitions ---------------------------------- */
#define PSA_HANDLE_MGR_INVALID_HANDLE ((uint16_t)PSA_NULL_HANDLE)
#define PSA_HANDLE_MGR_INVALID_FRIEND_OWNER 0 // Denoting invalid friend or invalid owner
// Handle manager pool indexes must be in range 0 - 0x7FFF.
// This is because the index is stored in the upper 16 bits of a handle,
// and the most significant bit must be zero to keep handles non-negative.
#define PSA_HANDLE_MGR_MAX_HANDLES_NUM 0x8000
/* -------------------------------------- Structs ------------------------------------ */
typedef struct psa_handle_item_t {
psa_handle_t handle; /* The user-exposed handle [unique identifier]. */
int32_t handle_owner; /* The partition ID of the handle creator. Allowed to get_mem() / destroy(). */
int32_t handle_friend; /* The partition ID of a "friend" partition. Allowed to get_mem(). */
void *handle_mem; /* Points to memory allocated by the use.r */
} psa_handle_item_t;
typedef struct psa_handle_manager_t {
// Handle generator uses only 16 bits, and wraps.
// The reason for this is that we use the 16 upper bits to store the handle's index in the handles pool (for performance reasons)
uint16_t handle_generator; /* A counter supplying handle numbers. */
uint16_t pool_size; /* The maximum number of handles that pool can contain. */
psa_handle_item_t *handles_pool; /* Holds couples of handles and their memory "blocks". */
} psa_handle_manager_t;
/*
handles_pool
|
|
|
--> *--------------------------------------------------------------------------*
| handle | handle | handle | | | ... |
*--------------------------------------------------------------------------*
| handle_owner | handle_owner | handle_owner | | | ... |
*--------------------------------------------------------------------------*
| handle_friend | handle_friend | handle_friend | | | ... |
*--------------------------------------------------------------------------*
| handle_mem | handle_mem | handle_mem | | | ... |
*--------------------------------------------------------------------------*
*/
/* ------------------------------------- Functions ----------------------------------- */
/*
* @brief Create unique handle identifier
*
* This function generates a unique handle identifier, and **couples** it with the received handle memory.
* If there is no vacant space for the new handle, the function fails.
*
* @note This function is expected to pass since it is always coupled with memory pool allocation of the same size.
* In case memory pool allocation fails, this function should not be called.
* This function will panic in the case of non-vacant space use.
*
* @param[in] handle_mgr A pointer to the handle manager object.
* @param[in] handle_mem A pointer to a pre-allocated handle memory for which to get a handle identifier.
* @param[in] friend_pid The partition ID allowed to `get_mem()` and `destroy()` in addition to the handle owner.
* Use `PSA_HANDLE_MGR_INVALID_FRIEND_OWNER` to denote that there is no friend partition.
* @return The created handle identifier
*/
psa_handle_t psa_hndl_mgr_handle_create(psa_handle_manager_t *handle_mgr, void *handle_mem, int32_t friend_pid);
/*
* @brief Remove a handle from the handle manager.
*
* @param handle_mgr A pointer to the handle manager object.
* @param handle The handle to be removed.
*/
void psa_hndl_mgr_handle_destroy(psa_handle_manager_t *handle_mgr, psa_handle_t handle);
/*
* @brief De-reference handle
*
* This function retrieves the pointer associated with the input <handle>.
*
* @note This function will panic if caller is not allowed to de-reference the memory,
* or handler does not correspond to a valid existing handle.
*
* @param handle_mgr A pointer to the handle manager object.
* @param handle The handle for which you request the corresponding memory handle.
* @return void* A pointer to the memory corresponding to the handle.
*/
void *psa_hndl_mgr_handle_get_mem(psa_handle_manager_t *handle_mgr, psa_handle_t handle);
#ifdef __cplusplus
}
#endif
#endif /* __MBED_HANDLE_MANAGER_H__ */
