RE: [PATCH v6 3/5] x86/mce, EDAC/mce_amd: Add support for new MCA_SYND{1,2} registers

[Zhuo, Qiuxu]

> From: Avadhut Naik <avadhut.naik@xxxxxxx>
> [...]
> --- a/include/trace/events/mce.h
> +++ b/include/trace/events/mce.h
> @@ -43,6 +43,7 @@ TRACE_EVENT(mce_record,
>  		__field(	u8,		bank		)
>  		__field(	u8,		cpuvendor	)
>  		__field(	u32,		microcode	)
> +		__dynamic_array(u8, v_data, sizeof(err->vendor))
>  	),
> 
>  	TP_fast_assign(
> @@ -65,9 +66,10 @@ TRACE_EVENT(mce_record,
>  		__entry->bank		= err->m.bank;
>  		__entry->cpuvendor	= err->m.cpuvendor;
>  		__entry->microcode	= err->m.microcode;
> +		memcpy(__get_dynamic_array(v_data), &err->vendor,
> +sizeof(err->vendor));
>  	),
> 
> -	TP_printk("CPU: %d, MCGc/s: %llx/%llx, MC%d: %016Lx, IPID: %016Lx,
> ADDR: %016Lx, MISC: %016Lx, SYND: %016Lx, RIP: %02x:<%016Lx>, TSC: %llx,
> PPIN: %llx, vendor: %u, CPUID: %x, time: %llu, socket: %u, APIC: %x,
> microcode: %x",
> +	TP_printk("CPU: %d, MCGc/s: %llx/%llx, MC%d: %016llx, IPID: %016llx,
> +ADDR: %016llx, MISC: %016llx, SYND: %016llx, RIP: %02x:<%016llx>, TSC:
> +%llx, PPIN: %llx, vendor: %u, CPUID: %x, time: %llu, socket: %u, APIC:
> +%x, microcode: %x, vendor data: %s",
>  		__entry->cpu,
>  		__entry->mcgcap, __entry->mcgstatus,
>  		__entry->bank, __entry->status,
> @@ -83,7 +85,8 @@ TRACE_EVENT(mce_record,
>  		__entry->walltime,
>  		__entry->socketid,
>  		__entry->apicid,
> -		__entry->microcode)
> +		__entry->microcode,
> +		__print_dynamic_array(v_data, 8))

What is the 2nd parameter '8' about? 

The 2nd parameter is about the element size. 
The element type is 'u8', as defined above. 
Therefore:

    __print_dynamic_array(v_data, sizeof(u8)))
    
-Qiuxu

[...]