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Add an initial MPU API 

Add a minimalistic HAL MPU API with the ability to prevent execution
in ram.
pull/8871/head
Russ Butler 2018-10-05 18:45:11 -05:00 committed by Martin Kojtal
parent 5e6dc940ba
commit 0f5b9eaf94
2 changed files with 229 additions and 0 deletions
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149
hal/mbed_mpu_api.c Normal file
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/* mbed Microcontroller Library
* Copyright (c) 2018 ARM Limited
*
* 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.
*/
#include "hal/mpu_api.h"
#include "cmsis.h"
void mbed_mpu_init()
{
mbed_mpu_enable_ram_xn(false);
}
void mbed_mpu_free()
{
mbed_mpu_enable_ram_xn(false);
}
void mbed_mpu_enable_ram_xn(bool enable)
{
#if MBED_MPU_ENABLED
// Flush memory writes before configuring the MPU.
__DSB();
const uint32_t regions = (MPU->TYPE & MPU_TYPE_DREGION_Msk) >> MPU_TYPE_DREGION_Pos;
// Disable the MCU
MPU->CTRL = 0;
// Reset all mapping
for (uint32_t i = 0; i < regions; i++) {
ARM_MPU_ClrRegion(i);
}
if (!enable) {
return;
}
/*
* ARMv6m and ARMv7m memory map:
*
* Start End Name Executable by default Mbed MPU protection
* 0x00000000 - 0x1FFFFFFF Code Yes Execute disabled for second half
* 0x20000000 - 0x3FFFFFFF SRAM Yes Execute disabled
* 0x40000000 - 0x5FFFFFFF Peripheral No
* 0x60000000 - 0x7FFFFFFF RAM Yes Execute disabled
* 0x80000000 - 0x9FFFFFFF RAM Yes Execute disabled
* 0xA0000000 - 0xBFFFFFFF Device No
* 0xC0000000 - 0xDFFFFFFF Device No
* 0xE0000000 - 0xFFFFFFFF System No
*/
if (regions >= 3) {
// Select region 0 and used it for the WT rom region
// - RAM 0x10000000 - 0x1FFFFFFF
MPU->RNR = 0;
// Set address to 0
MPU->RBAR = 0;
// Configure and enable region
MPU->RASR =
MPU_RASR_ENABLE_Msk |
ARM_MPU_RASR(
1, // DisableExec
ARM_MPU_AP_FULL, // AccessPermission
0, // TypeExtField
0, // IsShareable
1, // IsCacheable
0, // IsBufferable
// SubRegionDisable
(1 << 0) | // Disable Sub-region
(1 << 1) | // Disable Sub-region
(1 << 2) | // Disable Sub-region
(1 << 3) | // Disable Sub-region
(0 << 4) | // Enable Sub-region RAM 0x10000000 - 0x1FFFFFFF
(0 << 5) |
(0 << 6) |
(0 << 7),
ARM_MPU_REGION_SIZE_512MB // Size
);
// Select region 1 and used it for WBWA ram regions
// - SRAM 0x20000000 - 0x3FFFFFFF
// - RAM 0x60000000 - 0x7FFFFFFF
MPU->RNR = 1;
// Set address to 0
MPU->RBAR = 0;
// Configure and enable region
MPU->RASR =
MPU_RASR_ENABLE_Msk |
ARM_MPU_RASR(
1, // DisableExec
ARM_MPU_AP_FULL, // AccessPermission
1, // TypeExtField
0, // IsShareable
1, // IsCacheable
1, // IsBufferable
// SubRegionDisable
(1 << 0) | // Disable Sub-region
(0 << 1) | // Enable Sub-region SRAM 0x20000000 - 0x3FFFFFFF
(1 << 2) | // Disable Sub-region
(0 << 3) | // Enable Sub-region RAM 0x60000000 - 0x7FFFFFFF
(1 << 4) | // Disable Sub-region
(1 << 5) | // Disable Sub-region
(1 << 6) | // Disable Sub-region
(1 << 7), // Disable Sub-region
ARM_MPU_REGION_SIZE_4GB // Size
);
// Select region 2 and used it for the WT ram region
// - RAM RAM 0x80000000 - 0x9FFFFFFF
MPU->RNR = 2;
// Set address
MPU->RBAR = 0x80000000;
// Configure and enable region
MPU->RASR =
MPU_RASR_ENABLE_Msk |
ARM_MPU_RASR(
1, // DisableExec
ARM_MPU_AP_FULL, // AccessPermission
0, // TypeExtField
0, // IsShareable
1, // IsCacheable
0, // IsBufferable
~0U, // SubRegionDisable
ARM_MPU_REGION_SIZE_512MB // Size
);
}
// Enable the MPU
MPU->CTRL =
(1 << MPU_CTRL_PRIVDEFENA_Pos) | // Use the default memory map for unmapped addresses
(1 << MPU_CTRL_HFNMIENA_Pos) | // Keep MPU turned on for faults
(1 << MPU_CTRL_ENABLE_Pos); // Enable MPU
// Ensure changes take effect
__ISB();
__DSB();
#endif
}

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hal/mpu_api.h Normal file
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/** \addtogroup hal */
/** @{*/
/* mbed Microcontroller Library
* Copyright (c) 2018-2018 ARM Limited
*
* 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_MPU_API_H
#define MBED_MPU_API_H
#include <stdbool.h>
#include "cmsis.h"
#ifndef MBED_MPU_ENABLED
#if ((__ARM_ARCH_7M__ == 1U) || \
(__ARM_ARCH_7EM__ == 1U) || \
(__ARM_ARCH_6M__ == 1U))
#if defined (__MPU_PRESENT) && (__MPU_PRESENT == 1U)
#define MBED_MPU_ENABLED 1U
#else
#define MBED_MPU_ENABLED 0U
#endif
#elif ((__ARM_ARCH_7A__ == 1U) || \
(__ARM_ARCH_8M_BASE__ == 1U) || \
(__ARM_ARCH_8M_MAIN__ == 1U))
#define MBED_MPU_ENABLED 0U
#else
#error "Unknown architecture for MPU"
#endif
#endif
#ifdef __cplusplus
extern "C" {
#endif
/**
* Initialize the MPU
*
* Initialize or re-initialize the memory protection unit.
* It is implementation defined what region are protected
* by the MPU after initialization.
*/
void mbed_mpu_init(void);
/**
* Enable or disable ram MPU protection
*
* This function is used to mark all of RAM as execute never.
* When enabled code is only allowed to execute from flash.
*
* @param enable true to disable execution in ram, false otherwise
*/
void mbed_mpu_enable_ram_xn(bool enable);
/** Deinitialize the MPU
*
* Powerdown the MPU in preparation for powerdown, reset or jumping to another application.
*/
void mbed_mpu_free(void);
#ifdef __cplusplus
}
#endif
#endif
/** @}*/