On 03/07/2016 09:56 AM, David Miller wrote:

From: Khalid Aziz <redacted>
Date: Mon, 7 Mar 2016 08:07:53 -0700

quoted

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

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