page_allocator_config.h

00001 /*
00002  * Copyright (c) 2016, ARM Limited, All Rights Reserved
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License"); you may
00006  * not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  * http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00013  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 
00018 #ifndef __PAGE_ALLOCATOR_CONFIG_H__
00019 #define __PAGE_ALLOCATOR_CONFIG_H__
00020 /* This file can be compiled externally to provide the page allocator algorithm
00021  * for devices NOT supported by uVisor. For this purpose this file is copied as
00022  * is into the target build folder and compiled by the target build system. */
00023 
00024 /* We can only protect a small number of pages efficiently, so there should be
00025  * a relatively low limit to the number of pages.
00026  * By default a maximum of 16 pages are allowed. This can only be overwritten
00027  * by the porting engineer for the current platform. */
00028 #ifndef UVISOR_PAGE_MAX_COUNT
00029 #define UVISOR_PAGE_MAX_COUNT (16UL)
00030 #endif
00031 /* The number of pages is decided by the page size. A small page size leads to
00032  * a lot of pages, however, number of pages is capped for efficiency.
00033  * Furthermore, when allocating large continous memory, a too small page size
00034  * will lead to allocation failures. This can only be overwritten
00035  * by the porting engineer for the current platform. */
00036 #ifndef UVISOR_PAGE_SIZE_MINIMUM
00037 #define UVISOR_PAGE_SIZE_MINIMUM (1024UL)
00038 #endif
00039 
00040 /* Defines the number of uint32_t page owner masks in the owner map. */
00041 #define UVISOR_PAGE_MAP_COUNT ((UVISOR_PAGE_MAX_COUNT + 31) / 32)
00042 
00043 /* The page box_id is the box id which is 8-bit large. */
00044 typedef uint8_t page_owner_t;
00045 /* Define a unused value for the page table. */
00046 #define UVISOR_PAGE_UNUSED ((page_owner_t) (-1))
00047 /* Contains the total number of available pages. */
00048 extern uint8_t g_page_count_total;
00049 
00050 /** Sets the page bit in the page map array.
00051  * @param map   an array of `uint32_t` containing the page map
00052  * @param page  the index of the page to be set
00053  */
00054 static inline void page_allocator_map_set(uint32_t * const map, uint8_t page)
00055 {
00056     page += UVISOR_PAGE_MAP_COUNT * 32 - g_page_count_total;
00057     map[page / 32] |= (1UL << (page % 32));
00058 }
00059 
00060 /** Clears the page bit in the page map array.
00061  * @param map   an array of `uint32_t` containing the page map
00062  * @param page  the index of the page to be set
00063  */
00064 static inline void page_allocator_map_clear(uint32_t * const map, uint8_t page)
00065 {
00066     page += UVISOR_PAGE_MAP_COUNT * 32 - g_page_count_total;
00067     map[page / 32] &= ~(1UL << (page % 32));
00068 }
00069 
00070 /** Check if the page bit is set int the page map array.
00071  * @param map   an array of `uint32_t` containing the page map
00072  * @param page  the index of the page to be set
00073  * @retval 0    if page bit is not set
00074  * @retval 1    if page bit is set
00075  */
00076 static inline int page_allocator_map_get(const uint32_t * const map, uint8_t page)
00077 {
00078     page += UVISOR_PAGE_MAP_COUNT * 32 - g_page_count_total;
00079     return (map[page / 32] >> (page % 32)) & 0x1;
00080 }
00081 
00082 #endif /* __PAGE_ALLOCATOR_CONFIG_H__ */