Subject: Re: [PATCH v2] sparc64: Add support for Application Data Integrity
 (ADI)
To: David Miller <davem@davemloft.net>
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From: Khalid Aziz <khalid.aziz@oracle.com>
Organization: Oracle Corp
Message-ID: <56DDC2B6.6020009@oracle.com>
Date: Mon, 7 Mar 2016 11:04:38 -0700
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On 03/07/2016 09:56 AM, David Miller wrote:
> From: Khalid Aziz <khalid.aziz@oracle.com>
> Date: Mon, 7 Mar 2016 08:07:53 -0700
>
>> PR_GET_SPARC_ADICAPS
>
> Put this into a new ELF auxiliary vector entry via ARCH_DLINFO.
>
> So now all that's left is supposedly the TAG stuff, please explain
> that to me so I can direct you to the correct existing interface to
> provide that as well.
>
> Really, try to avoid prtctl, it's poorly typed and almost worse than
> ioctl().
>

The two remaining operations I am looking at are:

1. Is PSTATE.mcde bit set for the process? PR_SET_SPARC_ADI provides 
this in its return value in the patch I sent.

2. Is TTE.mcd set for a given virtual address? PR_GET_SPARC_ADI_STATUS 
provides this function in the patch I sent.

Setting and clearing version tags can be done entirely from userspace:

         while (addr < end) {
                 asm volatile(
                         "stxa %1, [%0]ASI_MCD_PRIMARY\n\t"
                         :
                         : "r" (addr), "r" (version));
                 addr += adicap.blksz;
         }
so I do not have to add any kernel code for tags.

Thanks,
Khalid