From: Andy Lutomirski <luto@amacapital.net>
To: Ingo Molnar <mingo@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Al Viro <viro@zeniv.linux.org.uk>, X86 ML <x86@kernel.org>,
Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux API <linux-api@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-arch <linux-arch@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Arnd Bergmann <arnd@arndb.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 6/9] x86, pkeys: add pkey set/get syscalls
Date: Sun, 17 Jul 2016 21:43:31 -0700 [thread overview]
Message-ID: <CALCETrWPM_jrF6saHPxoUL4vkjhhGBfizATXrFOW=+z5xycToQ@mail.gmail.com> (raw)
In-Reply-To: <20160714080701.GA14613@gmail.com>
On Thu, Jul 14, 2016 at 1:07 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Andy Lutomirski <luto@amacapital.net> wrote:
>
>> On Wed, Jul 13, 2016 at 12:56 AM, Ingo Molnar <mingo@kernel.org> wrote:
>> >
>> > * Andy Lutomirski <luto@amacapital.net> wrote:
>> >
>> >> > If we push a PKRU value into a thread between the rdpkru() and wrpkru(), we'll
>> >> > lose the content of that "push". I'm not sure there's any way to guarantee
>> >> > this with a user-controlled register.
>> >>
>> >> We could try to insist that user code uses some vsyscall helper that tracks
>> >> which bits are as-yet-unassigned. That's quite messy, though.
>> >
>> > Actually, if we turned the vDSO into something more like a minimal user-space
>> > library with the ability to run at process startup as well to prepare stuff
>> > then it's painful to get right only *once*, and there will be tons of other
>> > areas where a proper per thread data storage on the user-space side would be
>> > immensely useful!
>>
>> Doing this could be tricky: how exactly is the vDSO supposed to find per-thread
>> data without breaking existing glibc?
>
> So I think the way this could be done is by allocating it itself. The vDSO vma
> itself is 'external' to glibc as well to begin with - this would be a small
> extension to that concept.
But how does the vdso code find it? FS and GS are both spoken for by
existing userspace.
--Andy
next prev parent reply other threads:[~2016-07-18 4:43 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-07 12:47 [PATCH 0/9] [REVIEW-REQUEST] [v4] System Calls for Memory Protection Keys Dave Hansen
2016-07-07 12:47 ` [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit Dave Hansen
2016-07-07 14:40 ` Mel Gorman
2016-07-07 15:42 ` Dave Hansen
2016-07-07 12:47 ` [PATCH 2/9] mm: implement new pkey_mprotect() system call Dave Hansen
2016-07-07 14:40 ` Mel Gorman
2016-07-07 16:51 ` Dave Hansen
2016-07-08 10:15 ` Mel Gorman
2016-07-07 12:47 ` [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen
2016-07-07 12:47 ` [PATCH 4/9] x86: wire up mprotect_key() system call Dave Hansen
2016-07-07 12:47 ` [PATCH 5/9] x86, pkeys: allocation/free syscalls Dave Hansen
2016-07-07 14:40 ` Mel Gorman
2016-07-07 15:38 ` Dave Hansen
2016-07-07 12:47 ` [PATCH 6/9] x86, pkeys: add pkey set/get syscalls Dave Hansen
2016-07-07 14:45 ` Mel Gorman
2016-07-07 17:33 ` Dave Hansen
2016-07-08 7:18 ` Ingo Molnar
2016-07-08 16:32 ` Dave Hansen
2016-07-09 8:37 ` Ingo Molnar
2016-07-11 4:25 ` Andy Lutomirski
2016-07-11 7:35 ` Ingo Molnar
2016-07-11 14:28 ` Dave Hansen
2016-07-12 7:13 ` Ingo Molnar
2016-07-12 15:39 ` Dave Hansen
2016-07-11 14:50 ` Andy Lutomirski
2016-07-11 14:34 ` Dave Hansen
2016-07-11 14:45 ` Andy Lutomirski
2016-07-11 15:48 ` Dave Hansen
2016-07-12 16:32 ` Andy Lutomirski
2016-07-12 17:12 ` Dave Hansen
2016-07-12 22:55 ` Andy Lutomirski
2016-07-13 7:56 ` Ingo Molnar
2016-07-13 18:43 ` Andy Lutomirski
2016-07-14 8:07 ` Ingo Molnar
2016-07-18 4:43 ` Andy Lutomirski [this message]
2016-07-18 9:56 ` Ingo Molnar
2016-07-18 18:02 ` Dave Hansen
2016-07-18 20:12 ` Dave Hansen
2016-07-08 19:26 ` Dave Hansen
2016-07-08 10:22 ` Mel Gorman
2016-07-07 12:47 ` [PATCH 7/9] generic syscalls: wire up memory protection keys syscalls Dave Hansen
2016-07-07 12:47 ` [PATCH 8/9] pkeys: add details of system call use to Documentation/ Dave Hansen
2016-07-07 12:47 ` [PATCH 9/9] x86, pkeys: add self-tests Dave Hansen
2016-07-07 14:47 ` [PATCH 0/9] [REVIEW-REQUEST] [v4] System Calls for Memory Protection Keys Mel Gorman
2016-07-08 18:38 ` Hugh Dickins
-- strict thread matches above, loose matches on Subject: below --
2016-06-09 0:01 [PATCH 0/9] [v3] " Dave Hansen
2016-06-09 0:01 ` [PATCH 6/9] x86, pkeys: add pkey set/get syscalls Dave Hansen
2016-06-07 20:47 [PATCH 0/9] [v2] System Calls for Memory Protection Keys Dave Hansen
2016-06-07 20:47 ` [PATCH 6/9] x86, pkeys: add pkey set/get syscalls Dave Hansen
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