From: "H. Peter Anvin" <hpa@zytor.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Roland McGrath <roland@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: x86: get rid of the insane TIF_ABI_PENDING bit
Date: Mon, 15 Feb 2010 10:06:39 -0800 [thread overview]
Message-ID: <4B798D2F.7010701@zytor.com> (raw)
In-Reply-To: <20100215165012.GA20447@redhat.com>
On 02/15/2010 08:50 AM, Oleg Nesterov wrote:
>
> Could you please point me where do we check TS_COMPAT during return
> to user-mode?
>
Sorry, I was thinking about TIF_IA32, which is examined on line 415 of
entry_64.S.
>>> If a 64bit task execs a 32bit app, can't this TS_COMPAT break, say,
>>> syscall_get_arguments() ?
>>
>> At that point (this is after the exec!) we don't get arguments anyway.
>
> I meant /proc/pid/syscall, but even if I am right this probably
> doesn't matter.
What does getting the arguments from a process which has never done a
system call yet even mean? Presumably we get some kind of "null answer"
which depends on the default register set; in that case the compat null
answer is the correct one.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2010-02-15 18:07 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-15 16:17 x86: get rid of the insane TIF_ABI_PENDING bit Oleg Nesterov
2010-02-15 16:23 ` H. Peter Anvin
2010-02-15 16:50 ` Oleg Nesterov
2010-02-15 18:06 ` H. Peter Anvin [this message]
2010-02-15 18:52 ` Oleg Nesterov
2010-02-15 19:07 ` H. Peter Anvin
2010-02-15 19:10 ` H. Peter Anvin
2010-02-15 19:41 ` Roland McGrath
2010-02-15 20:07 ` H. Peter Anvin
2010-02-15 21:14 ` Roland McGrath
2010-02-15 20:43 ` H. Peter Anvin
2010-02-15 21:05 ` Roland McGrath
2010-02-16 10:19 ` Oleg Nesterov
2010-02-16 10:23 ` Andi Kleen
2010-02-16 14:01 ` [PATCH 0/3] Was: " Oleg Nesterov
2010-02-16 14:02 ` [PATCH 1/3] x86: set_personality_ia32() misses force_personality32 Oleg Nesterov
2010-02-16 23:27 ` [tip:x86/urgent] " tip-bot for Oleg Nesterov
2010-02-16 14:02 ` [PATCH 2/3] x86: set_personality_ia32() abuses TS_COMPAT Oleg Nesterov
2010-02-16 15:40 ` Linus Torvalds
2010-02-16 17:16 ` Oleg Nesterov
2010-02-16 17:38 ` H. Peter Anvin
2010-02-16 17:44 ` Oleg Nesterov
2010-02-16 17:51 ` H. Peter Anvin
2010-02-17 15:40 ` Oleg Nesterov
2010-02-16 18:43 ` Linus Torvalds
2010-02-16 14:03 ` [PATCH 3/3] x86: ELF_PLAT_INIT() shouldn't worry about TIF_IA32 Oleg Nesterov
2010-02-16 14:24 ` Oleg Nesterov
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