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

From David Miller <davem@davemloft.net>
Newsgroups linux.kernel
Subject Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI)
Date 2016-03-08 21:30 +0100
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References <raazF-899-29@gated-at.bofh.it> <ravXt-5uX-27@gated-at.bofh.it> <rawgO-5Tc-17@gated-at.bofh.it>
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From: Khalid Aziz <khalid.aziz@oracle.com>
Date: Tue, 8 Mar 2016 13:16:11 -0700

> On 03/08/2016 12:57 PM, David Miller wrote:
>> From: Khalid Aziz <khalid.aziz@oracle.com>
>> Date: Mon, 7 Mar 2016 14:06:43 -0700
>>
>>> Good questions. Isn't set of valid VAs already constrained by VA_BITS
>>> (set to 44 in arch/sparc/include/asm/processor_64.h)? As I see it we
>>> are already not using the top 4 bits. Please correct me if I am wrong.
>>
>> Another limiting constraint is the number of address bits coverable by
>> the 4-level page tables we use.  And this is sign extended so we have
>> a top-half and a bottom-half with a "hole" in the center of the VA
>> space.
>>
>> I want some clarification on the top bits during ADI accesses.
>>
>> If ADI is enabled, then the top bits of the virtual address are
>> intepreted as tag bits.  Once "verified" with the ADI settings, what
>> happense to these tag bits?  Are they dropped from the virtual address
>> before being passed down the TLB et al. for translations?
> 
> Bits 63-60 (tag bits) are dropped from the virtual address before
> being passed down the TLB for translation when PSTATE.mcde = 1.

Ok and you said that values 15 and 0 are special.

I'm just wondering if this means you can't really use ADI mappings in
the top half of the 64-bit address space.  If the bits are dropped, they
will be zero, but they need to be all 1's for the top-half of the VA
space since it's sign extended.

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Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-06 05:10 +0100
  Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 16:10 +0100
    Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Rob Gardner <rob.gardner@oracle.com> - 2016-03-07 16:40 +0100
      Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 16:50 +0100
      Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI) Andy Lutomirski <luto@amacapital.net> - 2016-03-07 16:50 +0100
        Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 17:10 +0100
          Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Dave Hansen <dave.hansen@linux.intel.com> - 2016-03-07 18:50 +0100
            Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI) Andy Lutomirski <luto@amacapital.net> - 2016-03-07 19:00 +0100
              Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Dave Hansen <dave.hansen@linux.intel.com> - 2016-03-07 19:20 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 19:50 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI) Andy Lutomirski <luto@amacapital.net> - 2016-03-07 20:00 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 20:30 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 20:50 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Dave Hansen <dave.hansen@linux.intel.com> - 2016-03-07 23:50 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Rob Gardner <rob.gardner@oracle.com> - 2016-03-08 02:40 +0100
            Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 22:10 +0100
              Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-08 21:00 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-08 21:20 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-08 21:30 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-08 22:10 +0100
    Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 17:50 +0100
      Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 19:00 +0100
    Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 18:00 +0100
      Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI) Andy Lutomirski <luto@amacapital.net> - 2016-03-07 19:10 +0100
        Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 19:30 +0100
          Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI) Andy Lutomirski <luto@amacapital.net> - 2016-03-07 20:00 +0100
            Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 20:30 +0100
            Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 20:50 +0100
              Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI) Andy Lutomirski <luto@amacapital.net> - 2016-03-07 21:00 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 21:50 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 22:00 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity (ADI) Andy Lutomirski <luto@amacapital.net> - 2016-03-07 22:10 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 22:20 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) James Morris <james.l.morris@oracle.com> - 2016-03-08 00:40 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) James Morris <james.l.morris@oracle.com> - 2016-03-08 01:00 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) James Morris <james.l.morris@oracle.com> - 2016-03-08 10:40 +0100
      Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 19:10 +0100
        Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Rob Gardner <rob.gardner@oracle.com> - 2016-03-07 19:20 +0100
          Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 19:30 +0100
            Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 20:20 +0100
              Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 22:40 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 22:40 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Rob Gardner <rob.gardner@oracle.com> - 2016-03-08 00:20 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-08 05:20 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Rob Gardner <rob.gardner@oracle.com> - 2016-03-08 00:20 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-08 00:30 +0100
              Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-08 01:30 +0100
                Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-08 05:30 +0100
            Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Rob Gardner <rob.gardner@oracle.com> - 2016-03-08 00:40 +0100
        Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 20:10 +0100
          Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 22:30 +0100
            Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) David Miller <davem@davemloft.net> - 2016-03-07 22:40 +0100
              Re: [PATCH v2] sparc64: Add support for Application Data Integrity  (ADI) Khalid Aziz <khalid.aziz@oracle.com> - 2016-03-07 23:40 +0100

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