Re: [PATCH 26/34] mm: implement new mprotect_key() system call

From	"Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 26/34] mm: implement new mprotect_key() system call
Date	2015-12-11 21:20 +0100
Message-ID	<qECkx-LZ-1@gated-at.bofh.it> (permalink)
References	(3 earlier) <qD799-75n-25@gated-at.bofh.it> <qDKNb-7Bs-7@gated-at.bofh.it> <qDPa9-1NH-3@gated-at.bofh.it> <qDQ6e-2qX-11@gated-at.bofh.it> <qDQpA-2N1-19@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On 12/09/2015 06:05 PM, Dave Hansen wrote:
> On 12/09/2015 08:45 AM, Michael Kerrisk (man-pages) wrote:
>>>>>> * Explanation of what a protection domain is.
>>>>
>>>> A protection domain is a unique view of memory and is represented by the
>>>> value in the PKRU register.
>> Out something about this in pkey(7), but explain what you mean by a
>> "unique view of memory".
> 
> Let's say there are only two protection keys: 0 and 1.  There are two
> disable bits per protection key (Access and Write Disable), so a two-key
> PKRU looks like:
> 
> |   PKEY0   |   PKEY1   |
> | AD0 | WD0 | AD1 | WD1 |
> 
> In this example, there are 16 possible protection domains, one for each
> possible combination of the 4 rights-disable bits.
> 
> "Changing a protection domain" would mean changing (setting or clearing)
> the value of any of those 4 bits.  Each unique value of PKRU represents
> a view of memory, or unique protection domain.

Again, some of this could make its way into pkey(7). And I guess there
are useful nuggets for that page to be found in Jon's article at
https://lwn.net/Articles/667156/

Thanks,

Michael




-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Thread

[PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 09/34] x86, pkeys: store protection in high VMA flags Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 09/34] x86, pkeys: store protection in high VMA flags Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 15:20 +0100
  [PATCH 32/34] x86, pkeys: add pkey set/get syscalls Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 29/34] x86: separate out LDT init from context init Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 31/34] x86, pkeys: allocation/free syscalls Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 12/34] signals, pkeys: notify userspace about protection key faults Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 20/34] x86, pkeys: differentiate instruction fetches Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 20/34] x86, pkeys: differentiate instruction fetches Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
  [PATCH 19/34] x86, pkeys: optimize fault handling in access_error() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 19/34] x86, pkeys: optimize fault handling in  access_error() Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
  [PATCH 18/34] mm: add gup flag to indicate "foreign" mm access Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 27/34] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 27/34] x86, pkeys: make mprotect_key() mask off additional  vm_flags Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:50 +0100
  [PATCH 23/34] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 23/34] x86, pkeys: add Kconfig prompt to existing config  option Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:30 +0100
  [PATCH 25/34] x86, pkeys: add arch_validate_pkey() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 25/34] x86, pkeys: add arch_validate_pkey() Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:50 +0100
  [PATCH 33/34] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
    Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-05 08:00 +0100
      Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-07 17:50 +0100
        Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-09 12:10 +0100
          Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-09 16:50 +0100
            Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-09 17:50 +0100
              Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-09 18:10 +0100
                Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-11 21:20 +0100
  [PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 22/34] x86, pkeys: dump PTE pkey in /proc/pid/smaps Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
  [PATCH 14/34] x86, pkeys: add functions to fetch PKRU Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
    Re: [PATCH 14/34] x86, pkeys: add functions to fetch PKRU Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 16:20 +0100
  [PATCH 11/34] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 02/34] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
    Re: [PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit  handling Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:10 +0100
      Re: [PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2015-12-08 19:40 +0100
  [PATCH 10/34] x86, pkeys: arch-specific protection bits Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
    Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 16:20 +0100
      Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Dave Hansen <dave@sr71.net> - 2015-12-08 17:40 +0100
        Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 18:30 +0100
          Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Dave Hansen <dave@sr71.net> - 2015-12-08 19:10 +0100
            Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:40 +0100
            Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:40 +0100
  [PATCH 06/34] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 05/34] x86, pkeys: define new CR4 bit Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 01/34] mm, gup: introduce concept of "foreign" get_user_pages() Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 17/34] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
    Re: [PATCH 17/34] x86, pkeys: check VMAs and PTEs for protection  keys Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
  [PATCH 13/34] x86, pkeys: fill in pkey field in siginfo Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 08/34] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 07/34] x86, pkeys: PTE bits for storing protection key Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  [PATCH 04/34] x86, pkeys: cpuid bit definition Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
  Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen <dave@sr71.net> - 2015-12-05 00:40 +0100
    Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski <luto@amacapital.net> - 2015-12-11 21:20 +0100
  Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski <luto@amacapital.net> - 2015-12-05 00:40 +0100

csiph-web