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mpu_api.h
1 
2 /** \addtogroup hal */
3 /** @{*/
4 /* mbed Microcontroller Library
5  * Copyright (c) 2018-2018 ARM Limited
6  * SPDX-License-Identifier: Apache-2.0
7  *
8  * Licensed under the Apache License, Version 2.0 (the "License");
9  * you may not use this file except in compliance with the License.
10  * You may obtain a copy of the License at
11  *
12  * http://www.apache.org/licenses/LICENSE-2.0
13  *
14  * Unless required by applicable law or agreed to in writing, software
15  * distributed under the License is distributed on an "AS IS" BASIS,
16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17  * See the License for the specific language governing permissions and
18  * limitations under the License.
19  */
20 #ifndef MBED_MPU_API_H
21 #define MBED_MPU_API_H
22 
23 #include "device.h"
24 #include <stdbool.h>
25 
26 #ifdef __cplusplus
27 extern "C" {
28 #endif
29 
30 #if DEVICE_MPU
31 
32 /**
33  * \defgroup hal_mpu MPU hal
34  *
35  * The MPU hal provides a simple MPU API to enhance device security by preventing
36  * execution from ram.
37  *
38  * # Defined behavior
39  * * The function ::mbed_mpu_init is safe to call repeatedly - Verified by ::mpu_init_test
40  * * The function ::mbed_mpu_free disables MPU protection - Verified by ::mpu_free_test
41  * * Execution from RAM results in a fault when execute never is enabled.
42  * This RAM includes heap, stack, data and zero init - Verified by ::mpu_fault_test_data,
43  * ::mpu_fault_test_bss, ::mpu_fault_test_stack and ::mpu_fault_test_heap.
44  * * Writing to ROM results in a fault when write never is enabled - Not verified
45  *
46  * # Undefined behavior
47  * * Calling any function other than ::mbed_mpu_init before the initialization of the MPU.
48  *
49  * @see hal_mpu_tests
50  *
51  * @{
52  */
53 
54 /**
55  * \defgroup hal_mpu_tests MPU hal tests
56  * The MPU test validates proper implementation of the MPU hal.
57  *
58  * To run the MPU hal tests use the command:
59  *
60  * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-mpu*
61  */
62 
63 
64 /**
65  * Initialize the MPU
66  *
67  * Initialize or re-initialize the memory protection unit.
68  * After initialization or re-initialization, ROM and RAM protection
69  * are both enabled.
70  */
71 void mbed_mpu_init(void);
72 
73 /**
74  * Enable or disable ROM MPU protection
75  *
76  * This function is used to mark all of ROM as read and execute only.
77  * When enabled writes to ROM cause a fault.
78  *
79  * By default writes to ROM are disabled.
80  *
81  * @param enable true to disable writes to ROM, false otherwise
82  */
83 void mbed_mpu_enable_rom_wn(bool enable);
84 
85 /**
86  * Enable or disable ram MPU protection
87  *
88  * This function is used to mark all of RAM as execute never.
89  * When enabled code is only allowed to execute from flash.
90  *
91  * By default execution from RAM is disabled.
92  *
93  * @param enable true to disable execution from RAM, false otherwise
94  */
95 void mbed_mpu_enable_ram_xn(bool enable);
96 
97 /** Deinitialize the MPU
98  *
99  * Powerdown the MPU in preparation for powerdown, reset or jumping to another application.
100  */
101 void mbed_mpu_free(void);
102 
103 /**@}*/
104 
105 #else
106 
107 #define mbed_mpu_init()
108 
109 #define mbed_mpu_enable_rom_wn(enable) (void)enable
110 
111 #define mbed_mpu_enable_ram_xn(enable) (void)enable
112 
113 #define mbed_mpu_free()
114 
115 #endif
116 
117 #ifdef __cplusplus
118 }
119 #endif
120 
121 #endif
122 
123 /** @}*/
mbed_mpu_enable_ram_xn
void mbed_mpu_enable_ram_xn(bool enable)
Enable or disable ram MPU protection.
mbed_mpu_enable_rom_wn
void mbed_mpu_enable_rom_wn(bool enable)
Enable or disable ROM MPU protection.
mbed_mpu_init
void mbed_mpu_init(void)
Initialize the MPU.
mbed_mpu_free
void mbed_mpu_free(void)
Deinitialize the MPU.
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