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/**
******************************************************************************
* @file Cortex/CORTEXM_ModePrivilege/Src/main.c
* @author MCD Application Team
* @brief Description of the CortexM4 Mode Privilege example.
******************************************************************************
* @attention
*
* Copyright (c) 2017 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "main.h"
/** @addtogroup STM32F4xx_HAL_Examples
* @{
*/
/** @addtogroup CORTEXM_ModePrivilege
* @{
*/
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define SP_PROCESS_SIZE 0x200 /* Process stack size */
#define SP_PROCESS 0x02 /* Process stack */
#define SP_MAIN 0x00 /* Main stack */
#define THREAD_MODE_PRIVILEGED 0x00 /* Thread mode has privileged access */
#define THREAD_MODE_UNPRIVILEGED 0x01 /* Thread mode has unprivileged access */
/* Private function prototypes -----------------------------------------------*/
static __INLINE void __SVC(void);
/* Private macro -------------------------------------------------------------*/
#if defined ( __CC_ARM )
__ASM void __SVC(void)
{
SVC 0x01
BX R14
}
#elif defined ( __ICCARM__ )
static __INLINE void __SVC() { __ASM ("svc 0x01");}
#elif defined ( __GNUC__ )
static __INLINE void __SVC() { __ASM volatile ("svc 0x01");}
#endif
/* Private variables ---------------------------------------------------------*/
__IO uint8_t PSPMemAlloc[SP_PROCESS_SIZE];
__IO uint32_t Index = 0, PSPValue = 0, CurrentStack = 0, ThreadMode = 0;
/* Private function prototypes -----------------------------------------------*/
static void SystemClock_Config(void);
/* Private functions ---------------------------------------------------------*/
/**
* @brief Main program
* @param None
* @retval None
*/
int main(void)
{
/* STM32F4xx HAL library initialization:
- Configure the Flash prefetch, instruction and Data caches
- Configure the Systick to generate an interrupt each 1 msec
- Set NVIC Group Priority to 4
- Global MSP (MCU Support Package) initialization
*/
HAL_Init();
/* Configure the system clock to 168 MHz */
SystemClock_Config();
/* Switch Thread mode Stack from Main to Process ###########################*/
/* Initialize memory reserved for Process Stack */
for(Index = 0; Index < SP_PROCESS_SIZE; Index++)
{
PSPMemAlloc[Index] = 0x00;
}
/* Set Process stack value */
__set_PSP((uint32_t)PSPMemAlloc + SP_PROCESS_SIZE);
/* Select Process Stack as Thread mode Stack */
__set_CONTROL(SP_PROCESS);
/* Execute ISB instruction to flush pipeline as recommended by Arm */
__ISB();
/* Get the Thread mode stack used */
if((__get_CONTROL() & 0x02) == SP_MAIN)
{
/* Main stack is used as the current stack */
CurrentStack = SP_MAIN;
}
else
{
/* Process stack is used as the current stack */
CurrentStack = SP_PROCESS;
/* Get process stack pointer value */
PSPValue = __get_PSP();
}
/* Switch Thread mode from privileged to unprivileged ######################*/
/* Thread mode has unprivileged access */
__set_CONTROL(THREAD_MODE_UNPRIVILEGED | SP_PROCESS);
/* Execute ISB instruction to flush pipeline as recommended by Arm */
__ISB();
/* Unprivileged access mainly affect ability to:
- Use or not use certain instructions such as MSR fields
- Access System Control Space (SCS) registers such as NVIC and SysTick */
/* Check Thread mode privilege status */
if((__get_CONTROL() & 0x01) == THREAD_MODE_PRIVILEGED)
{
/* Thread mode has privileged access */
ThreadMode = THREAD_MODE_PRIVILEGED;
}
else
{
/* Thread mode has unprivileged access */
ThreadMode = THREAD_MODE_UNPRIVILEGED;
}
/* Switch back Thread mode from unprivileged to privileged #################*/
/* Try to switch back Thread mode to privileged (Not possible, this can be
done only in Handler mode) */
__set_CONTROL(THREAD_MODE_PRIVILEGED | SP_PROCESS);
/* Execute ISB instruction to flush pipeline as recommended by Arm */
__ISB();
/* Generate a system call exception, and in the ISR switch back Thread mode
to privileged */
__SVC();
/* Check Thread mode privilege status */
if((__get_CONTROL() & 0x01) == THREAD_MODE_PRIVILEGED)
{
/* Thread mode has privileged access */
ThreadMode = THREAD_MODE_PRIVILEGED;
}
else
{
/* Thread mode has unprivileged access */
ThreadMode = THREAD_MODE_UNPRIVILEGED;
}
/* Infinite loop */
while (1)
{
}
}
/**
* @brief System Clock Configuration
* The system Clock is configured as follow :
* System Clock source = PLL (HSE)
* SYSCLK(Hz) = 168000000
* HCLK(Hz) = 168000000
* AHB Prescaler = 1
* APB1 Prescaler = 4
* APB2 Prescaler = 2
* HSE Frequency(Hz) = 25000000
* PLL_M = 25
* PLL_N = 336
* PLL_P = 2
* PLL_Q = 7
* VDD(V) = 3.3
* Main regulator output voltage = Scale1 mode
* Flash Latency(WS) = 5
* @param None
* @retval None
*/
static void SystemClock_Config(void)
{
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_OscInitTypeDef RCC_OscInitStruct;
/* Enable Power Control clock */
__HAL_RCC_PWR_CLK_ENABLE();
/* The voltage scaling allows optimizing the power consumption when the device is
clocked below the maximum system frequency, to update the voltage scaling value
regarding system frequency refer to product datasheet. */
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/* Enable HSE Oscillator and activate PLL with HSE as source */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 25;
RCC_OscInitStruct.PLL.PLLN = 336;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = 7;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
/* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2
clocks dividers */
RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5);
/* STM32F405x/407x/415x/417x Revision Z and upper devices: prefetch is supported */
if (HAL_GetREVID() >= 0x1001)
{
/* Enable the Flash prefetch */
__HAL_FLASH_PREFETCH_BUFFER_ENABLE();
}
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t* file, uint32_t line)
{
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* Infinite loop */
while (1)
{
}
}
#endif
/**
* @}
*/
/**
* @}
*/
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