IAR 用于调试的HardFault异常处理

亦凉 2022-05-15 08:07 996阅读 0赞

# 用于调试的hardfault #

在编写STM32程序代码时由于自己的粗心会发现有时候程序跑着跑着就进入了

HardFault\_Handler中断，按照经验来说进入HardFault\_Handler故障的原因主要有两个方面：

1：内存溢出或则访问越界。

2：堆栈溢出。

发生异常后我们可以首先查看LR寄存器的值，确认当前使用的堆栈是MSP还是PSP，然后找到相对应的堆栈指针，并在内存中查看相对应堆栈的内容，内核将R0~R3，R12，LR，PC，XPRS寄存器依次入栈，其中LR即为发生异常前PC将要执行的下一条指令地址。

/******************************************************************************/
    /* Cortex-M4 Processor Interruption and Exception Handlers */ 
    /******************************************************************************/
    void hard_fault_handler_c( unsigned int* hardfault_args )
    {
        unsigned char svc_num;
        unsigned int stacked_r0;
        unsigned int stacked_r1;
        unsigned int stacked_r2;
        unsigned int stacked_r3;
        unsigned int stacked_r12;
        unsigned int stacked_lr;
        unsigned int stacked_pc;
        unsigned int stacked_psr;
    
        stacked_r0 = ( ( unsigned long )hardfault_args[0] );
        stacked_r1 = ( ( unsigned long )hardfault_args[1] );
        stacked_r2 = ( ( unsigned long )hardfault_args[2] );
        stacked_r3 = ( ( unsigned long )hardfault_args[3] );
    
        stacked_r12 = ( ( unsigned long )hardfault_args[4] );
        stacked_lr = ( ( unsigned long )hardfault_args[5] );
        stacked_pc = ( ( unsigned long )hardfault_args[6] );
        stacked_psr = ( ( unsigned long ) hardfault_args[7] );
    
        svc_num = ( ( char* )stacked_r0 )[-2];
    
    
        /******************* Add yourdebug trace here ***********************/
        hardfault_args[0] = stacked_r0 + stacked_r1;
    
        printf("r0: %x\r\n", stacked_r0);
        ......
    
        while(1)
        {
        }
    }
    
    #if   defined ( __ICCARM__ )
    void HardFault_Handler( void )
    {
        __ASM("TST lr, #4\n");
    
        __ASM("ITE EQ\n"
    
        "MRSEQ r0, MSP\n"
    
        "MRSNE r0, PSP\n");
    
        __ASM("MOV r1, LR\n");
    
        __ASM("B hard_fault_handler_c");
    }
    #else   //#if defined ( __CC_ARM )

## 注意上边汇编哪里 ##

IAR Embedded Workbench for ARM version 7.30 (and earlier) accepted constructions like:

[...]
    __ASM("ITE EQ");
    __ASM("MRSEQ R0, MSP");
    __ASM("MRSNE R0, PSP");
    [...]

The above is a bug which is corrected in IAR Embedded Workbench for ARM version 7.40.1.

The code above will generate diagnostic messages like:

> Error\[Ta117\]: IT-block ends prematurely, or there is a label within the IT-block  
> Discussion  
> The construction above is unsafe, as in-between the asm()-statements it was possible to place ordinary C source code.

Suggested rewrite  
Change the construction into a single inline assebler statement, with multiple lines.

The above construction should be rewritten to:

\[…\]  
\_\_ASM(“ITE EQ \\n”  
“MRSEQ R0, MSP \\n”  
“MRSNE R0, PSP”);  
\[…\]