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From: Roland McGrath <roland@redhat.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: x86: get rid of the insane TIF_ABI_PENDING bit
Date: Mon, 15 Feb 2010 13:14:57 -0800 (PST)	[thread overview]
Message-ID: <20100215211457.C2E143E8@magilla.sf.frob.com> (raw)
In-Reply-To: H. Peter Anvin's message of  Monday, 15 February 2010 12:07:50 -0800 <4B79A996.2090606@zytor.com>

> It's entirely possible it is completely superfluous.  The patch in
> question only moves the setting.  I don't know what gdb or strace use to
> distinguish a 32-bit and a 64-bit process, which is why I thought it
> might have something to do with ptrace.

Well, whatever it that might be, they have no way to know about the
TS_COMPAT setting.  TS_COMPAT affects three things: audit_syscall_entry()
parameters, asm/syscall.h stuff, and is_compat_task()--nothing that is
directly visible from userland unless you count /proc/pid/syscall values.
Notably, that includes syscall_get_error() that is used in signal recovery.

AFAICT the only interesting use of is_compat_task() is the drivers/input stuff.


Thanks,
Roland

  reply	other threads:[~2010-02-15 21:15 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-15 16:17 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
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 [this message]
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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