Hi,
I'm trying to find an example for how to setup and use MPU. The SDK documentation gives the details of how to setup a MPU region, but how do I setup privilege's for accessing functions. Can you provide a simple example code where there is a global variable at a specific MPU protected region and 3 functions where one function has read/write access, one function has only read access and one function has no read and write access.
Regards,
Harsha
Hi Harsha,
Please find the file -
/*
* Copyright (C) 2018-2021 Texas Instruments Incorporated
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of Texas Instruments Incorporated nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
* OWNER 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.
*/
#include <stdio.h>
#include <kernel/dpl/DebugP.h>
#include "ti_drivers_config.h"
#include "ti_drivers_open_close.h"
#include "ti_board_open_close.h"
MpuP_RegionConfig temp_function = {
.baseAddr = 0x70080000,
.size = MpuP_RegionSize_1K,
.attrs.isEnable = 1,
.attrs.isCacheable = 1,
.attrs.isBufferable = 0,
.attrs.isSharable = 1,
.attrs.isExecuteNever = 1,
.attrs.tex = 0,
.attrs.accessPerm = 0,
.attrs.subregionDisableMask = 0
};
uint8_t variable_function[1024] __attribute__((section(".data.test_function"))) = {0x01, 0x02, 0x03, 0x04, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F};
extern void MpuP_setRegionAsm(uint32_t regionId, uint32_t regionBaseAddr,
uint32_t sizeAndEnble, uint32_t regionAttrs);
void MpuP_setRegionLocalFunction(uint32_t regionNum, void * addr, uint32_t size, MpuP_RegionAttrs *attrs)
{
uint32_t baseAddress, sizeAndEnable;
uintptr_t key;
uint32_t value = size;
DebugP_assertNoLog( regionNum < 16U);
/* size 5b field */
value = (value & (uint32_t)0x1F);
/* If N is the value in size field, the region size is 2N+1 bytes. */
sizeAndEnable = ((uint32_t)(attrs->subregionDisableMask & (uint32_t)0xFF) << (uint32_t)8)
| ((uint32_t)(value & (uint32_t)0x1F) << (uint32_t)1)
| ((uint32_t)(attrs->isEnable & (uint32_t)0x1) << (uint32_t)0);
/* align base address to region size */
baseAddress = ((uint32_t)addr & ~( (1U <<((uint64_t)value+1U))-1U ));
/* get region attribute mask */
uint32_t regionAttrs =
((uint32_t)(attrs->isExecuteNever & (uint32_t)0x1) << (uint32_t)12)
| ((uint32_t)(attrs->accessPerm & (uint32_t)0x7) << (uint32_t)8)
| ((uint32_t)(attrs->tex & (uint32_t)0x7) << (uint32_t)3)
| ((uint32_t)(attrs->isSharable & (uint32_t)0x1) << (uint32_t)2)
| ((uint32_t)(attrs->isCacheable & (uint32_t)0x1) << (uint32_t)1)
| ((uint32_t)(attrs->isBufferable & (uint32_t)0x1) << (uint32_t)0);
key = HwiP_disable();
MpuP_setRegionAsm(regionNum, baseAddress, sizeAndEnable, regionAttrs);
HwiP_restore(key);
}
void function_a(void)
{
/* Disable MPU */
temp_function.attrs.isEnable = 0;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
/* Change the Access Permission */
temp_function.attrs.accessPerm = 3;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
/* Enable MPU */
temp_function.attrs.isEnable = 1;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
DebugP_log("Function A\r\n");
/* Testing the Read Access */
DebugP_log("Variable Function Data %x\r\n", variable_function[0]);
/* Testing the Write Access */
variable_function[0] = 0xFF;
/* Testing the Read Access again to prevent optimization */
DebugP_log("Variable Function Data %x\r\n", variable_function[0]);
/* Disable MPU */
temp_function.attrs.isEnable = 0;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
/* Revert the Access Permission */
temp_function.attrs.accessPerm = 0;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
/* Enable MPU */
temp_function.attrs.isEnable = 1;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
}
void function_b(void)
{
/* Disable MPU */
temp_function.attrs.isEnable = 0;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
/* Revert the Access Permission */
temp_function.attrs.accessPerm = 6;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
/* Enable MPU */
temp_function.attrs.isEnable = 1;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
DebugP_log("Function B\r\n");
DebugP_log("Variable Function Data %x\r\n", variable_function[0]);
/* Writing will lead to abort, so commented */
//variable_function[0] = 0xAA;
/* Disable MPU */
temp_function.attrs.isEnable = 0;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
/* Revert the Access Permission */
temp_function.attrs.accessPerm = 0;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
/* Enable MPU */
temp_function.attrs.isEnable = 1;
MpuP_setRegionLocalFunction(4, (void *)temp_function.baseAddr, temp_function.size, (MpuP_RegionAttrs *)&temp_function.attrs.isEnable);
}
void function_c(void)
{
DebugP_log("Function C\r\n");
/* Reading will lead to abort, so commented */
//DebugP_log("Variable Function Data %x\r\n", variable_function[0]);
/* Writing will lead to abort, so commented */
//variable_function[0] = 0xCC;
}
void hello_world_main(void *args)
{
/* Open drivers to open the UART driver for console */
Drivers_open();
Board_driversOpen();
//DebugP_log("Hello World!\r\n");
/* A Function which can read and write the variable */
function_a();
/* A Function which can read the variable */
function_b();
/* A Function which cannot access the variable */
function_c();
Board_driversClose();
Drivers_close();
}
The MPU settings for the same are also mentioned here -
Hope it helps.
Best Regards,
Aakash
Hi Aakash,
I tried the above example but it seems to fail. Please let me know what I have been doing wrong here.
/*
* Copyright (C) 2021 Texas Instruments Incorporated
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of Texas Instruments Incorporated nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
* OWNER 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.
*/
#include <stdio.h>
#include <kernel/dpl/DebugP.h>
#include <kernel/dpl/MpuP_armv7.h>
#include "ti_drivers_config.h"
#include "ti_drivers_open_close.h"
#include "ti_board_open_close.h"
/*
* This is an empty project provided for all cores present in the device.
* User can use this project to start their application by adding more SysConfig modules.
*
* This application does driver and board init and just prints the pass string on the console.
* In case of the main core, the print is redirected to the UART console.
* For all other cores, CCS prints are used.
*/
MpuP_RegionConfig localMpuRegionConfig = {
.baseAddr = 0x70080000,
.size = MpuP_RegionSize_1K,
.attrs = {
.isEnable = 1,
.isCacheable = 1,
.isBufferable = 0,
.isSharable = 1,
.isExecuteNever = 1,
.tex = 0,
.accessPerm = MpuP_AP_ALL_BLOCK,
.subregionDisableMask = 0x0u
},
};
uint8_t secure_variable[1024] __attribute__((section(".data.secure_variable"))) = {0x01, 0x02, 0x03, 0x04, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F};
void access_permission_set(uint16_t perm)
{
/* Disable MPU */
localMpuRegionConfig.attrs.isEnable = 0;
localMpuRegionConfig.attrs.isCacheable = 0;
MpuP_setRegion(6, (void *)localMpuRegionConfig.baseAddr, localMpuRegionConfig.size, (MpuP_RegionAttrs *)&localMpuRegionConfig.attrs);
/* Change the Access Permission */
localMpuRegionConfig.attrs.accessPerm = (uint8_t)perm;
MpuP_setRegion(6, (void *)localMpuRegionConfig.baseAddr, localMpuRegionConfig.size, (MpuP_RegionAttrs *)&localMpuRegionConfig.attrs);
/* Enable MPU */
localMpuRegionConfig.attrs.isEnable = 1;
localMpuRegionConfig.attrs.isCacheable = 1;
MpuP_setRegion(6, (void *)localMpuRegionConfig.baseAddr, localMpuRegionConfig.size, (MpuP_RegionAttrs *)&localMpuRegionConfig.attrs);
}
void function_a(void)
{
access_permission_set(MpuP_AP_ALL_RW);
DebugP_log("Function A\r\n");
/* Testing the Read Access */
DebugP_log("Variable Function Data %x\r\n", secure_variable[0]);
/* Testing the Write Access */
secure_variable[0] = 0xFF;
/* Testing the Read Access again to prevent optimization */
DebugP_log("Variable Function Data %x\r\n", secure_variable[0]);
access_permission_set(MpuP_AP_ALL_BLOCK);
}
void function_b(void)
{
access_permission_set(MpuP_AP_ALL_R);
DebugP_log("Function B\r\n");
DebugP_log("Variable Function Data %x\r\n", secure_variable[0]);
/* Writing will lead to abort, so commented */
secure_variable[0] = 0xAA;
DebugP_log("Variable Function Data %x\r\n", secure_variable[0]);
access_permission_set(MpuP_AP_ALL_BLOCK);
}
void function_c(void)
{
DebugP_log("Function C\r\n");
/* Reading will lead to abort, so commented */
DebugP_log("Variable Function Data %x\r\n", secure_variable[0]);
/* Writing will lead to abort, so commented */
secure_variable[0] = 0xCC;
DebugP_log("Variable Function Data %x\r\n", secure_variable[0]);
}
void empty_main(void *args)
{
/* Open drivers to open the UART driver for console */
Drivers_open();
Board_driversOpen();
function_a();
function_b();
function_c();
DebugP_log("All tests have passed!!\r\n");
while(1)
{
}
Board_driversClose();
Drivers_close();
}
MPU config in syscfg
Output on uart terminal:
Function b and c should have triggered an abort but neither does.
Further
Regards,
Harsha
Hi Aakash,
Thank you, I had forgotten to change the name of the section in the code where I'm assigning the secure_variable.
Now the example works.
Thank you for your support.
Regards,
Harsha