Re: [PATCH V3 01/23] perf/x86: Support outputting XMM registers

[Thomas Gleixner]

On Tue, 26 Mar 2019, Liang, Kan wrote:
> On 3/25/2019 8:11 PM, Thomas Gleixner wrote:
> 
> -#define REG_RESERVED (~((1ULL << PERF_REG_X86_MAX) - 1ULL))
> +#define REG_RESERVED 0

What's the point of having this around?

>  int perf_reg_validate(u64 mask)
>  {
>       if (!mask || mask & REG_RESERVED)
>               return -EINVAL;

 mask & 0 == 0, right? So which bits are you checking here?

Thanks,

        tglx