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  * +8 is used for ARMv7-M MPUs, where a shift of up to 7-bits may be required
00042  * to align MPU regions. */
00043 #define UVISOR_PAGE_MAP_COUNT ((UVISOR_PAGE_MAX_COUNT + 31 + 8) / 32)
00044 
00045 /* The page box_id is the box id which is 8-bit large. */
00046 typedef uint8_t page_owner_t;
00047 /* Define a unused value for the page table. */
00048 #define UVISOR_PAGE_UNUSED ((page_owner_t) (-1))
00049 /* Contains the total number of available pages. */
00050 extern uint8_t g_page_count_total;
00051 /* Contains the shift of the page owner mask. */
00052 extern uint8_t g_page_map_shift;
00053 /* Contains the ARMv7-MPU rounded page end. */
00054 extern uint32_t g_page_head_end_rounded;
00055 
00056 /** Sets the page bit in the page map array.
00057  * @param map   an array of `uint32_t` containing the page map
00058  * @param page  the index of the page to be set
00059  */
00060 static inline void page_allocator_map_set(uint32_t * const map, uint8_t page)
00061 {
00062     page += g_page_map_shift;
00063     map[page / 32] |= (1UL << (page % 32));
00064 }
00065 
00066 /** Clears the page bit in the page map array.
00067  * @param map   an array of `uint32_t` containing the page map
00068  * @param page  the index of the page to be set
00069  */
00070 static inline void page_allocator_map_clear(uint32_t * const map, uint8_t page)
00071 {
00072     page += g_page_map_shift;
00073     map[page / 32] &= ~(1UL << (page % 32));
00074 }
00075 
00076 /** Check if the page bit is set int the page map array.
00077  * @param map   an array of `uint32_t` containing the page map
00078  * @param page  the index of the page to be set
00079  * @retval 0    if page bit is not set
00080  * @retval 1    if page bit is set
00081  */
00082 static inline int page_allocator_map_get(const uint32_t * const map, uint8_t page)
00083 {
00084     page += g_page_map_shift;
00085     return (map[page / 32] >> (page % 32)) & 0x1;
00086 }
00087 
00088 #endif /* __PAGE_ALLOCATOR_CONFIG_H__ */