[Crash-utility] [PATCH] Fix pvops Xen detection for arm machine

[HAGIO KAZUHITO(萩尾 一仁)]

-----Original Message-----
> Since the xen_start_info on the arm/arm64 platform is static defined:
> 
> ./arm/xen/enlighten.c:40:static struct start_info _xen_start_info;
> ./arm/xen/enlighten.c:41:struct start_info *xen_start_info = &_xen_start_info;
> ./arm/xen/enlighten.c:42:EXPORT_SYMBOL(xen_start_info);
> 
> The is_pvops_xen() in commit 4badc6229c69f5cd9da7eb7bdf400a53ec6db01a
> ("Fix pvops Xen detection for kernels >= v4.20") always return TRUE.
> Then the following error will be reported because p2m_mid_missing
> and xen_p2m_addr are not defined:
> 
> 	crash: cannot resolve "p2m_top"
> 
> For the arm/arm64 platform, fix it by using xen_vcpu_info instead of
> xen_start_info to detect Xen dumps.
> 
> Signed-off-by: Qi Zheng <zhengqi.arch at bytedance.com>

I cannot test it on arm, but the patch looks good to me.

Acked-by: Kazuhito Hagio <k-hagio-ab at nec.com>

Thanks,
Kazu

> ---
>  kernel.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel.c b/kernel.c
> index f4598ea..4b4d789 100644
> --- a/kernel.c
> +++ b/kernel.c
> @@ -10757,11 +10757,18 @@ is_pvops_xen(void)
>  	     STREQ(sym, "paravirt_patch_default")))
>  		return TRUE;
> 
> -	if (symbol_exists("xen_start_info") &&
> -	    readmem(symbol_value("xen_start_info"), KVADDR, &addr,
> -	    sizeof(void *), "xen_start_info", RETURN_ON_ERROR) &&
> -	    addr != 0)
> +	if (machine_type("ARM") || machine_type("ARM64")) {
> +		if (symbol_exists("xen_vcpu_info") &&
> +		    readmem(symbol_value("xen_vcpu_info"), KVADDR, &addr,
> +		    sizeof(void *), "xen_vcpu_info", RETURN_ON_ERROR) &&
> +		    addr != 0)
> +			return TRUE;
> +	} else if (symbol_exists("xen_start_info") &&
> +		   readmem(symbol_value("xen_start_info"), KVADDR, &addr,
> +		   sizeof(void *), "xen_start_info", RETURN_ON_ERROR) &&
> +		   addr != 0) {
>  		return TRUE;
> +	}
> 
>  	return FALSE;
>  }
> --
> 2.11.0