Re: [PATCH] arm64: stacktrace: Factor out some common code info on_stack()

[Will Deacon]

On Thu, May 07, 2020 at 05:28:19PM +0800, Yunfeng Ye wrote:
> diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
> index fdb913cc0bcb..b92bef2fb6cd 100644
> --- a/arch/arm64/include/asm/stacktrace.h
> +++ b/arch/arm64/include/asm/stacktrace.h
> @@ -69,27 +69,40 @@ extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
> 
>  DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
> 
> -static inline bool on_irq_stack(unsigned long sp,
> +static inline bool on_stack(unsigned long sp, unsigned long low,
> +				unsigned long high, enum stack_type type,
>  				struct stack_info *info)
>  {
> -	unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
> -	unsigned long high = low + IRQ_STACK_SIZE;
> -
> -	if (!low)
> -		return false;
> -
>  	if (sp < low || sp >= high)
>  		return false;
> 
>  	if (info) {
>  		info->low = low;
>  		info->high = high;
> -		info->type = STACK_TYPE_IRQ;
> +		info->type = type;
>  	}
> -
>  	return true;
>  }
> 
> +static inline bool on_valid_stack(unsigned long sp, unsigned long low,
> +				unsigned long high, enum stack_type type,
> +				struct stack_info *info)
> +{
> +	if (!low)
> +		return false;
> +
> +	return on_stack(sp, low, high, type, info);
> +}

Do we need this as distinct from on_stack()? Afaict, 'low' is never
going to be NULL for the on_stack() callers, so I suggest just having
on_stack() check 'low' and getting everybody to call that instead.

Make sense?

Will