From: Dmitry Safonov <dsafonov@virtuozzo.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Adam Borowski <kilobyte@angband.pl>
Cc: Ingo Molnar <mingo@kernel.org>, Andrei Vagin <avagin@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Andy Lutomirski <luto@kernel.org>,
Thomas Garnier <thgarnie@google.com>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: linux-next: x86: Unalbe to run x32 processes on the x86_64 kernel
Date: Tue, 21 Mar 2017 15:50:11 +0300 [thread overview]
Message-ID: <5b3938fb-ee84-c78d-be9b-e3ba6656065d@virtuozzo.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1703211339200.3617@nanos>
On 03/21/2017 03:49 PM, Thomas Gleixner wrote:
> On Tue, 21 Mar 2017, Adam Borowski wrote:
>> On Tue, Mar 21, 2017 at 07:45:39AM +0100, Ingo Molnar wrote:
>>> * Andrei Vagin <avagin@gmail.com> wrote:
>>>
>>>> # first bad commit: [45fc8757d1d2128e342b4e7ef39adedf7752faac] x86:
>>>> Make the GDT remapping read-only on 64-bit
>>>
>>> Just wondering, does the following commit fix it:
>>>
>>> 5b781c7e317f x86/tls: Forcibly set the accessed bit in TLS segments
>>
>> It does fix i386 but not x32.
>>
>> By "x32" I mean CONFIG_X86_X32, by "i386" CONFIG_IA32_EMULATION, contrary to
>> Andrei's first report. The naming of the new ABI wasn't too fortunate...
>
> The X32 issue is unrelated to the GDT mapping.
>
> What happens is that the mmap rework from Dmitry switched X32 to use 64bit
> mappings, which is wrong. X32 has 64bit instructions and syscalls and 32bit
> address space.
Hmm, in_compat_syscall() checks x32 syscall bit.
I'll take a look, what happens there.
> Dmitry, can you please have a look and fix that up? For reproduction just
> compile helloworld.c with gcc -mx32.
Sure, thanks.
--
Dmitry
next prev parent reply other threads:[~2017-03-21 12:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-20 23:57 linux-next: x86: Unalbe to run x32 processes on the x86_64 kernel Andrei Vagin
2017-03-21 1:32 ` Adam Borowski
2017-03-21 5:17 ` Andrei Vagin
2017-03-21 6:45 ` Ingo Molnar
2017-03-21 7:59 ` Adam Borowski
2017-03-21 12:49 ` Thomas Gleixner
2017-03-21 12:50 ` Dmitry Safonov [this message]
2017-03-21 15:59 ` Dmitry Safonov
2017-03-21 16:28 ` Andy Lutomirski
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