cortex-m3 m4 异常机制

文章写的很好，待整理

1.【STM32】HardFault问题详细分析及调试笔记

https://blog.csdn.net/m0_54916619/article/details/129979222

需备注：

cortex m4:  实际行为是，寄存器按照编号从小到大的顺序在栈帧中从数值较小地址往数值较大的地址排列.    进入异常时自动入栈R0-R3 R12 LR PSR

2.   stm32死机问题的处理

https://blog.csdn.net/qq_27087571/article/details/84580532

void hard_fault_handler_c(unsigned int * hardfault_args)
{
  static System_Crash_Info crash_info;
  memset(&crash_info, 0, sizeof(System_Crash_Info));

  crash_info.is_crash = 1;
  crash_info.crash_time = (unsigned int)HAL_GetTick();

  crash_info.stacked_r0 = ((unsigned long) hardfault_args[0]);
  crash_info.stacked_r1 = ((unsigned long) hardfault_args[1]);
  crash_info.stacked_r2 = ((unsigned long) hardfault_args[2]);
  crash_info.stacked_r3 = ((unsigned long) hardfault_args[3]);
  crash_info.stacked_r12 = ((unsigned long) hardfault_args[4]);
  crash_info.stacked_lr = ((unsigned long) hardfault_args[5]);
  crash_info.stacked_pc = ((unsigned long) hardfault_args[6]);
  crash_info.stacked_psr = ((unsigned long) hardfault_args[7]); 

  crash_info.MFSR = (*((volatile unsigned char *)(0xE000ED28))); //存储器管理fault状态寄存器
  crash_info.BFSR = (*((volatile unsigned char *)(0xE000ED29))); //总线fault状态寄存器
  crash_info.UFSR = (*((volatile unsigned short int *)(0xE000ED2A)));//用法fault状态寄存器
  crash_info.HFSR = (*((volatile unsigned long *)(0xE000ED2C)));  //硬fault状态寄存器
  crash_info.DFSR = (*((volatile unsigned long *)(0xE000ED30))); //调试fault状态寄存器
  crash_info.MMAR = (*((volatile unsigned long *)(0xE000ED34))); //存储管理地址寄存器
  crash_info.BFAR = (*((volatile unsigned long *)(0xE000ED38))); //总线fault地址寄存器  

  u8 ret = STMFLASH_EraseSector(STMFLASH_GetFlashSector(SYS_CRASH_INFO_ADDR));
  u8 ret2 = STMFLASH_Write(SYS_CRASH_INFO_ADDR, (u32 *)(&crash_info), (3+sizeof(System_Crash_Info))/4);

  while (1);
}

这里的潜在意思是， ARM平台的C函数入参，按顺序，依次可以获取到R0 R1 R2 R3 等，所以可以通过静态的crash_info将其记录下来。

3.  RTOS任务切换和异常的相关性很大

基于STM32 F103 CM3内核 freeRTOS 任务切换原理

https://zhuanlan.zhihu.com/p/599020378

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