ARM Cortex M3如何在硬故障之前确定程序计数器值？ [英] ARM Cortex M3 How do I determine the program counter value before a hard fault?

问题描述

我有一个使用STM32F103（ARM Cortex M3）的嵌入式项目，在发布模式下偶尔会出现硬故障。作为恢复的一部分，我想从硬故障之前检索PC值，并将其存储在电池供电区域的以后调试中。

我如何确定程序计数器在硬故障点的值？显然，PC现在被设置在硬突破中断的位置。

我应该在哪里看？那里有正常模式寄存器银行的地址？

谢谢！

解决方案

Cortex-M3使用与经典ARM类似的异常处理模式，例如在其他帖子中没有提及中止模式。我建议您阅读此应用笔记。例如，对于硬故障：

SCB-> BFAR的值表示导致总线故障的内存地址
并且如果SCB-> CFSR寄存器中的位BFARVALID置1，则有效。 SCB-> MMFAR的
值表示导致内存
管理故障的内存地址，如果SCB-> CFSR
寄存器中的MMFARVALID位置1，则该值有效。

要确定异常时的PC值，需要检查堆栈;在执行处理程序之前，处理器推送R0-R3，R12，PC和LR。所使用的堆栈可以是主（如果LR的位2为0）或过程（否则）。有关详细信息，请参阅应用笔记的第13页。

I have an embedded project using a STM32F103 (ARM Cortex M3), it is getting a occasionally getting hard fault in release mode. As part of recovery, I would like to retrieve the PC value from before the hard fault and store it for later debugging in the battery backed region.

How would I determine the value of the program counter at the point of the hard fault? Obviously, the PC is now set to its location within the hardfault interrupt.

Where should I look? It there an address for the normal mode register bank?

Thanks!

解决方案

Cortex-M3 uses a quite different model of exception handling from the "classic" ARM, e.g. it doesn't have "abort mode" mentioned in the other post. I suggest you to read this app note. For example, for the Hard Fault:

The value of SCB->BFAR indicates the memory address that caused a Bus Fault and is valid if the bit BFARVALID in the SCB->CFSR register is set. The value of SCB->MMFAR indicates the memory address that caused a Memory Management Fault and is valid if the bit MMFARVALID in the SCB->CFSR register is set.

To determine the PC value at the time of exception you need to examine the stack; the processor pushes R0-R3, R12, PC and LR before executing the handler. The stack used can be either Main (if bit 2 of LR is 0) or Process (otherwise). See page 13 of the app note for details.

这篇关于ARM Cortex M3如何在硬故障之前确定程序计数器值？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！