Re: [PATCH v3 4/4] x86, mpx: extend siginfo structure to include bound violation information

[Ren Qiaowei <qiaowei.ren@intel.com>]

On 01/27/2014 09:53 AM, H. Peter Anvin wrote:
> On 01/26/2014 05:34 PM, Ren Qiaowei wrote:
>>>
>> I agree with you and we should suppress all the warnings as possible. If
>> I use (unsgined long) to cast like the following code, what do you think
>> about it? sizeof(long) will be 4 for 32-bit.
>>
>>      info->si_lower = (void __user *)(unsigned long)
>>          (xsave_buf->bndregs.bndregs[2*bndregno]);
>>      info->si_upper = (void __user *)(unsigned long)
>>      (~xsave_buf->bndregs.bndregs[2*bndregno+1]);
>>
>
> That is the way it is usually done, yes.  Add a comment saying something
> like:
>
> 	/* Note: the upper 32 bits are ignored in 32-bit mode. */
>
> It is worth watching out a bit here, though, because you could be
> running a 32-bit process on top of a 64-bit kernel.
>
Ok. I will update it in next version.

Thanks,
Qiaowei