From: Andy Lutomirski <luto@amacapital.net>
To: Stefani Seibold <stefani@seibold.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de,
mingo@redhat.com, ak@linux.intel.com, aarcange@redhat.com,
john.stultz@linaro.org
Subject: Re: [PATCH] Add VDSO time function support for x86 32-bit kernel
Date: Thu, 13 Dec 2012 11:32:16 -0800 [thread overview]
Message-ID: <CALCETrWmYpEh9pLiohF+yu9FnrVfSNdHB_TQOKL6+LkdTF+cVw@mail.gmail.com> (raw)
In-Reply-To: <1355383038.18653.2.camel@wall-e>
On Wed, Dec 12, 2012 at 11:17 PM, Stefani Seibold <stefani@seibold.net> wrote:
> Am Mittwoch, den 12.12.2012, 22:47 -0800 schrieb H. Peter Anvin:
>> Should be a simple matter of sharing pages. Look perhaps at the x32 vdso for a hint.
>>
>
>
>> >
>> >Any idea or clean solution how i can map the 64 bit vgtod into the 32
>> >bit address space? Thats the only problem i see.
>> >
>
> No, i see no special handling for x32 vdso to do this. I am not sure if
> x32 vdso can access the 64 bit address space of vsyscall_gtod_data. I
> can't test this due the lack of a x32 abi system.
>
>
x32's vdso cheats -- x32 code can see high addresses just fine. The
toolchain just makes it difficult.
Your best bet is probably to just map the vvar page twice -- once at
the same address as native 32-bit mode (but only for compat tasks)
would use and once in the usual fixmap location. You can't use the
fixmap for the compat mapping, though, since it would be a *user*
address.
For HPET support, you'd have to have special support. I'd say to skip
it for compat mode.
--Andy
--
Andy Lutomirski
AMA Capital Management, LLC
next prev parent reply other threads:[~2012-12-13 19:32 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-12 20:19 [PATCH] Add VDSO time function support for x86 32-bit kernel stefani
2012-12-12 23:34 ` H. Peter Anvin
2012-12-13 5:53 ` Stefani Seibold
2012-12-13 6:10 ` H. Peter Anvin
2012-12-13 6:14 ` H. Peter Anvin
2012-12-13 6:17 ` Stefani Seibold
2012-12-13 6:47 ` H. Peter Anvin
2012-12-13 7:17 ` Stefani Seibold
2012-12-13 19:32 ` Andy Lutomirski [this message]
2012-12-14 0:09 ` H. Peter Anvin
2012-12-14 0:20 ` Andy Lutomirski
2012-12-14 0:36 ` H. Peter Anvin
2012-12-14 1:32 ` H. Peter Anvin
2012-12-14 1:42 ` Andy Lutomirski
2012-12-14 1:49 ` H. Peter Anvin
2012-12-14 2:11 ` Andy Lutomirski
2012-12-14 2:18 ` H. Peter Anvin
2012-12-14 2:20 ` Andy Lutomirski
2012-12-14 8:34 ` [CRIU] " Pavel Emelyanov
2012-12-14 18:35 ` H. Peter Anvin
2012-12-14 18:44 ` Andy Lutomirski
2012-12-14 18:47 ` H. Peter Anvin
2012-12-14 20:12 ` Cyrill Gorcunov
2012-12-14 21:08 ` H. Peter Anvin
2012-12-14 21:20 ` Cyrill Gorcunov
2012-12-14 21:21 ` H. Peter Anvin
2012-12-14 21:27 ` Andy Lutomirski
2012-12-14 22:00 ` H. Peter Anvin
2012-12-14 22:25 ` Cyrill Gorcunov
2012-12-14 22:27 ` H. Peter Anvin
2012-12-14 22:43 ` Cyrill Gorcunov
2012-12-14 22:48 ` H. Peter Anvin
2012-12-14 23:48 ` John Stultz
2012-12-14 23:55 ` H. Peter Anvin
2012-12-17 9:05 ` Pavel Emelyanov
[not found] ` <fb2e871b-3e2a-4e96-9eb9-cb2dd4f66eaa@email.android! .com>
2012-12-17 15:21 ` H. Peter Anvin
2012-12-17 18:56 ` Pavel Emelyanov
2012-12-17 18:57 ` H. Peter Anvin
2012-12-14 22:46 ` H. Peter Anvin
2012-12-14 23:09 ` Stefani Seibold
2012-12-14 23:29 ` H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2012-12-11 16:11 stefani
2012-12-11 19:27 ` John Stultz
2012-12-11 19:37 ` Andy Lutomirski
2012-12-11 20:54 ` Stefani Seibold
2012-12-11 21:18 ` Andy Lutomirski
2012-12-11 21:28 ` Stefani Seibold
2012-12-11 19:37 ` Andy Lutomirski
2012-12-11 20:40 ` Stefani Seibold
2012-12-12 1:29 ` Andy Lutomirski
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