Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI)

[Khalid Aziz]

On 03/07/2016 09:56 AM, David Miller wrote:
> From: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
> 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