stm32 - Issue in using "HAL_UART_Transmit" in FreeRTOS-MPU Usermode (Non-Priviledge) task on STM32F412
问题描述
I am using the FreeRTOS-MPU port with STM32F412 to achieve memory protection. I have successfully made both tasks UserMode(Non-Privilege) and PrivilegeMode. But I am not able to run the "HAL_UART_Transmit" API (or similar HAL APIs)in UserMode which result in Memory Fault. However, the same API is working properly in the Privilege mode tasks.
Does anyone have idea What am I missing?
My Project Linker Scrip is as below which is taken from STM32F4 SDK FreeRTOS_MPU project example:
/*
******************************************************************************
**
** File : LinkerScript.ld
**
** Author : Auto-generated by Ac6 System Workbench
**
** Abstract : Linker script for STM32F412CGUx series
** 1024Kbytes FLASH and 256Kbytes RAM
**
** Set heap size, stack size and stack location according
** to application requirements.
**
** Set memory bank area and size if external memory is used.
**
** Target : STMicroelectronics STM32
**
** Distribution: The file is distributed “as is,” without any warranty
** of any kind.
**
*****************************************************************************
/* Entry Point */
ENTRY(Reset_Handler)
/* Highest address of the user mode stack */
_estack = 0x20040000; /* end of RAM */
/* Generate a link error if heap and stack don't fit into RAM */
_Min_Heap_Size = 0x200; /* required amount of heap */
_Min_Stack_Size = 0x400; /* required amount of stack */
/* Specify the memory areas */
MEMORY
{
FLASH_priv (rx) : ORIGIN = 0x08000000, LENGTH = 16K
FLASH (rx) : ORIGIN = 0x08004000, LENGTH = 1008K
RAM_priv (xrw) : ORIGIN = 0x20000000, LENGTH = 2048
RAM (xrw) : ORIGIN = 0x20000800, LENGTH = 254K
}
/* Variables used by FreeRTOS-MPU. */
_Privileged_Functions_Region_Size = 16K;
_Privileged_Data_Region_Size = 2048;
__FLASH_segment_start__ = ORIGIN( FLASH_priv );
__FLASH_segment_end__ = __FLASH_segment_start__ + LENGTH( FLASH_priv ) + LENGTH( FLASH );
__privileged_functions_start__ = ORIGIN( FLASH_priv );
__privileged_functions_end__ = __privileged_functions_start__ + _Privileged_Functions_Region_Size;
__SRAM_segment_start__ = ORIGIN( RAM_priv );
__SRAM_segment_end__ = __SRAM_segment_start__ + LENGTH( RAM_priv ) + LENGTH( RAM );
__privileged_data_start__ = ORIGIN( RAM_priv );
__privileged_data_end__ = __privileged_data_start__ + _Privileged_Data_Region_Size;
/* Define output sections */
SECTIONS
{
/* The startup code goes first into FLASH */
.isr_vector :
{
. = ALIGN(4);
KEEP(*(.isr_vector)) /* Startup code */
. = ALIGN(4);
} >FLASH_priv
.privileged_functions :
{
. = ALIGN(4);
*(privileged_functions)
*(privileged_functions*)
. = ALIGN(4);
} >FLASH_priv
/* The program code and other data goes into FLASH */
.text :
{
. = ALIGN(4);
*(.text) /* .text sections (code) */
*(.text*) /* .text* sections (code) */
*(.glue_7) /* glue arm to thumb code */
*(.glue_7t) /* glue thumb to arm code */
*(.eh_frame)
KEEP (*(.init))
KEEP (*(.fini))
. = ALIGN(4);
_etext = .; /* define a global symbols at end of code */
} >FLASH
/* Constant data goes into FLASH */
.rodata :
{
. = ALIGN(4);
*(.rodata) /* .rodata sections (constants, strings, etc.) */
*(.rodata*) /* .rodata* sections (constants, strings, etc.) */
. = ALIGN(4);
} >FLASH
.ARM.extab : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
.ARM : {
__exidx_start = .;
*(.ARM.exidx*)
__exidx_end = .;
} >FLASH
.preinit_array :
{
PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array*))
PROVIDE_HIDDEN (__preinit_array_end = .);
} >FLASH
.init_array :
{
PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(SORT(.init_array.*)))
KEEP (*(.init_array*))
PROVIDE_HIDDEN (__init_array_end = .);
} >FLASH
.fini_array :
{
PROVIDE_HIDDEN (__fini_array_start = .);
KEEP (*(SORT(.fini_array.*)))
KEEP (*(.fini_array*))
PROVIDE_HIDDEN (__fini_array_end = .);
} >FLASH
.pbss :
{
. = ALIGN(4);
_spbss = .;
*(privileged_data)
*(privileged_data*)
. = ALIGN(4);
_epbss = .;
} >RAM_priv
/* used by the startup to initialize data */
_sipdata = LOADADDR(.pdata);
.pdata :
{
. = ALIGN(4);
_spdata = .;
*(privileged_initialized_data)
*(privileged_initialized_data*)
. = ALIGN(4);
_epdata = .;
} >RAM_priv AT> FLASH_priv
/* used by the startup to initialize data */
_sidata = LOADADDR(.data);
/* Initialized data sections goes into RAM, load LMA copy after code */
.data :
{
. = ALIGN(4);
_sdata = .; /* create a global symbol at data start */
*(.data) /* .data sections */
*(.data*) /* .data* sections */
. = ALIGN(4);
_edata = .; /* define a global symbol at data end */
} >RAM AT> FLASH
/* Uninitialized data section */
. = ALIGN(4);
.bss :
{
/* This is used by the startup in order to initialize the .bss secion */
_sbss = .; /* define a global symbol at bss start */
__bss_start__ = _sbss;
*(.bss)
*(.bss*)
*(COMMON)
. = ALIGN(4);
_ebss = .; /* define a global symbol at bss end */
__bss_end__ = _ebss;
} >RAM
/* User_heap_stack section, used to check that there is enough RAM left */
._user_heap_stack :
{
. = ALIGN(8);
PROVIDE ( end = . );
PROVIDE ( _end = . );
. = . + _Min_Heap_Size;
. = . + _Min_Stack_Size;
. = ALIGN(8);
} >RAM
/* Remove information from the standard libraries */
/DISCARD/ :
{
libc.a ( * )
libm.a ( * )
libgcc.a ( * )
}
.ARM.attributes 0 : { *(.ARM.attributes) }
}
解决方案
您需要设置 MPU 以允许用户模式访问 UART 外设(以及 UART 驱动程序库使用的任何其他外设。
首先创建一个 MPU 区域,从地址 0x40000000 到 0x60000000(大小:0x20000000),具有用户模式读写访问权限。
我建议在向量表中添加一个 MPU 故障处理程序,以便您知道什么时候出现错误。
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