记一次STM32H503冷启动后进入HardFult_Handler的问题

文章目录

前言
问题发现
问题处理
后记

前言

最近一个板子用了STM32H503KBU6芯片，刚用就发现个问题，这个芯片通过调试器调试可以正常工作，但是下电后再冷启动程序就无法正常工作了。最后测试发现这个问题还是稍微有些偏门的（主要原因是使用官方工具生成的代码直接就有问题）。

问题发现

需要说明的是我这里用的是 LL 库，HAL 库不一定存在这个问题。

接上调试器，关闭调试复位芯片选项，可以查看到芯片进入了HardFult_Handler，问题出在MX_USART2_UART_Init：

但是实际上去查看或者调试MX_USART2_UART_Init是没有问题的，这个问题只出现在冷启动的时候。后来发现问题其实在上面一行MX_RTC_Init。这个函数中在冷启动时会去复位backup域：

这个动作会清除SRAM2，

默认情况下编译出来的栈是在 SRAM2 上的，前面的 MX_GPIO_Init() 把 GPIOB=0x42020400 缓存在 [SP+4] ，约为 0x20007E94 。 Backup Domain reset 将其清零。随后 UART 初始化从 [SP+4] 取出 r0=0 ，访问 [r0 + 8] ，即 0x00000008 ，最终进入 HardFault 。

问题处理

发现问题处理起来就比较简单了，只要把栈内存定位到 SRAM1 上就行，我这里选择修改链接脚本（ STM32H503xx_FLASH.ld ）来实现相关调整。

把原本的RAM中的SRAM2单独拆分出来，这样后面栈就被定位到了SRAM1上：

bash 复制代码

/* Memories definition */
MEMORY
{
  /* RAM    (xrw)    : ORIGIN = 0x20000000,   LENGTH = 32K */
  RAM      (xrw)    : ORIGIN = 0x20000000,   LENGTH = 16K
  SRAM2    (xrw)    : ORIGIN = 0x20004000,   LENGTH = 16K
  /* BOOT: FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 56K */
  /* APP : FLASH (rx) : ORIGIN = 0x08010000, LENGTH = 56K */
  FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 56K
}
/* Highest address of the user mode stack */
_estack = ORIGIN(RAM) + LENGTH(RAM); /* end of "RAM" Ram type memory */
_sstack = _estack - _Min_Stack_Size;

这个修改虽然处理好了栈的部分，但是需要使用SRAM2时就需要设置段，然后手动将数据定位到该段上来使用了：

bash 复制代码

 .sram2_bss (NOLOAD) :
  {
    . = ALIGN(4);
    __sram2_bss_start__ = .;

    KEEP(*(.sram2_bss))
    KEEP(*(.sram2_bss.*))

    . = ALIGN(4);
    __sram2_bss_end__ = .;
  } > SRAM2

使用时可以用下面方式定位：

c 复制代码

__attribute__((section(".sram2_bss"), aligned(sizeof(8))))
static uint8_t mem_pool_buf[8192] = {0};

需要注意的是这里定义的 sram2_bss 这个段的内存可能需要手动清零才保险，可以在 MX_RTC_Init 后，最初使用前使用下面代码来清零：

c 复制代码

  extern uint8_t __sram2_bss_start__[];
  extern uint8_t __sram2_bss_end__[];
  size_t size = (uintptr_t)__sram2_bss_end__ - (uintptr_t)__sram2_bss_start__;
  memset(__sram2_bss_start__, 0, size);

完整的链接脚本如下：

bash 复制代码

/*
 ******************************************************************************
 **
 ** @file        : LinkerScript.ld
 **
 ** @author      : Auto-generated by STM32CubeIDE
 **
 ** @brief       : Linker script for STM32H503xx Device from STM32H5 series
 **                      128Kbytes FLASH
 **                      32Kbytes 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.
 **
 ******************************************************************************
 ** @attention
 **
 ** Copyright (c) 2023 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.
 **
 ******************************************************************************
 */

/* Entry Point */
ENTRY(Reset_Handler)


/* Memories definition */
MEMORY
{
  /* RAM    (xrw)    : ORIGIN = 0x20000000,   LENGTH = 32K */
  RAM      (xrw)    : ORIGIN = 0x20000000,   LENGTH = 16K
  SRAM2    (xrw)    : ORIGIN = 0x20004000,   LENGTH = 16K
  /* BOOT: FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 56K */
  /* APP : FLASH (rx) : ORIGIN = 0x08010000, LENGTH = 56K */
  FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 56K
}
/* Highest address of the user mode stack */
_estack = ORIGIN(RAM) + LENGTH(RAM); /* end of "RAM" Ram type memory */
_sstack = _estack - _Min_Stack_Size;

_Min_Heap_Size = 0x400;      /* required amount of heap  */
_Min_Stack_Size = 0x800; /* required amount of stack */

/* Sections */
SECTIONS
{
  /* The startup code into "FLASH" Rom type memory */
  .isr_vector :
  {
    . = ALIGN(4);
    KEEP(*(.isr_vector)) /* Startup code */
    . = ALIGN(4);
  } >FLASH

  /* The program code and other data into "FLASH" Rom type memory */
  .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 into "FLASH" Rom type memory */
  .rodata :
  {
    . = ALIGN(4);
    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
    . = ALIGN(4);
  } >FLASH

  .ARM.extab (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
  {
    . = ALIGN(4);
    *(.ARM.extab* .gnu.linkonce.armextab.*)
    . = ALIGN(4);
  } >FLASH

  .ARM (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
  {
    . = ALIGN(4);
    __exidx_start = .;
    *(.ARM.exidx*)
    __exidx_end = .;
    . = ALIGN(4);
  } >FLASH

  .preinit_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
  {
    . = ALIGN(4);
    PROVIDE_HIDDEN (__preinit_array_start = .);
    KEEP (*(.preinit_array*))
    PROVIDE_HIDDEN (__preinit_array_end = .);
    . = ALIGN(4);
  } >FLASH

  .init_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
  {
    . = ALIGN(4);
    PROVIDE_HIDDEN (__init_array_start = .);
    KEEP (*(SORT(.init_array.*)))
    KEEP (*(.init_array*))
    PROVIDE_HIDDEN (__init_array_end = .);
    . = ALIGN(4);
  } >FLASH

  .fini_array (READONLY) : /* The READONLY keyword is only supported in GCC11 and later, remove it if using GCC10 or earlier. */
  {
    . = ALIGN(4);
    PROVIDE_HIDDEN (__fini_array_start = .);
    KEEP (*(SORT(.fini_array.*)))
    KEEP (*(.fini_array*))
    PROVIDE_HIDDEN (__fini_array_end = .);
    . = ALIGN(4);
  } >FLASH

  /* Used by the startup to initialize data */
  _sidata = LOADADDR(.data);

  /* Initialized data sections into "RAM" Ram type memory */
  .data :
  {
    . = ALIGN(4);
    _sdata = .;        /* create a global symbol at data start */
    *(.data)           /* .data sections */
    *(.data*)          /* .data* sections */
    *(.RamFunc)        /* .RamFunc sections */
    *(.RamFunc*)       /* .RamFunc* sections */

    . = ALIGN(4);

  } >RAM AT> FLASH

  /* Initialized TLS data section */
  .tdata : ALIGN(4)
  {
    *(.tdata .tdata.* .gnu.linkonce.td.*)
    . = ALIGN(4);
    _edata = .;        /* define a global symbol at data end */
    PROVIDE(__data_end = .);
    PROVIDE(__tdata_end = .);
  } >RAM AT> FLASH

  PROVIDE( __tdata_start = ADDR(.tdata) );
  PROVIDE( __tdata_size = __tdata_end - __tdata_start );

  PROVIDE( __data_start = ADDR(.data) );
  PROVIDE( __data_size = __data_end - __data_start );

  PROVIDE( __tdata_source = LOADADDR(.tdata) );
  PROVIDE( __tdata_source_end = LOADADDR(.tdata) + SIZEOF(.tdata) );
  PROVIDE( __tdata_source_size = __tdata_source_end - __tdata_source );

  PROVIDE( __data_source = LOADADDR(.data) );
  PROVIDE( __data_source_end = __tdata_source_end );
  PROVIDE( __data_source_size = __data_source_end - __data_source );


  /* Uninitialized data section into "RAM" Ram type memory */
  /* Uninitialized TLS data section */
  .tbss (NOLOAD) : ALIGN(4)
  {
    _sbss = .;         /* define a global symbol at bss start */
    __bss_start__ = _sbss;
    *(.tbss .tbss.*)
    . = ALIGN(4);
    PROVIDE( __tbss_end = . );
  } >RAM

  PROVIDE( __tbss_start = ADDR(.tbss) );
  PROVIDE( __tbss_size = __tbss_end - __tbss_start );
  PROVIDE( __tbss_offset = ADDR(.tbss) - ADDR(.tdata) );

  PROVIDE( __tls_base = __tdata_start );
  PROVIDE( __tls_end = __tbss_end );
  PROVIDE( __tls_size = __tls_end - __tls_base );
  PROVIDE( __tls_align = MAX(ALIGNOF(.tdata), ALIGNOF(.tbss)) );
  PROVIDE( __tls_size_align = (__tls_size + __tls_align - 1) & ~(__tls_align - 1) );
  PROVIDE( __arm32_tls_tcb_offset = MAX(8, __tls_align) );
  PROVIDE( __arm64_tls_tcb_offset = MAX(16, __tls_align) );

  .bss (NOLOAD) : ALIGN(4)
  {
    /* This is used by the startup in order to initialize the .bss section */
    *(.bss)
    *(.bss*)
    *(COMMON)

    . = ALIGN(4);
    _ebss = .;         /* define a global symbol at bss end */
    __bss_end__ = _ebss;
      PROVIDE( __bss_end = .);
  } >RAM
  PROVIDE( __non_tls_bss_start = ADDR(.bss) );

  PROVIDE( __bss_start = __tbss_start );
  PROVIDE( __bss_size = __bss_end - __bss_start );

  .sram2_bss (NOLOAD) :
  {
    . = ALIGN(4);
    __sram2_bss_start__ = .;

    KEEP(*(.sram2_bss))
    KEEP(*(.sram2_bss.*))

    . = ALIGN(4);
    __sram2_bss_end__ = .;
  } > SRAM2

  /* User_heap_stack section, used to check that there is enough "RAM" Ram  type memory left */
  ._user_heap_stack (NOLOAD) :
  {
    . = ALIGN(8);
    PROVIDE ( end = . );
    PROVIDE ( _end = . );
    . = . + _Min_Heap_Size;
    . = . + _Min_Stack_Size;
    . = ALIGN(8);
  } >RAM

  /* Remove information from the compiler libraries */
  /DISCARD/ :
  {
    libc.a:* ( * )
    libm.a:* ( * )
    libgcc.a:* ( * )
  }

  .ARM.attributes 0 : { *(.ARM.attributes) }
}

后记

不停的换平台带来的就是不停的踩坑，虽然很花时间，不过很多新平台在特定场合下用起来还是很不错的。