From: Oleg Nesterov <oleg@redhat.com>
To: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
Pavel Emelyanov <xemul@parallels.com>
Subject: Re: [PATCH] x86: make PTRACE_GETREGSET return 32-bit regs if 64-bit process entered kernel with int 80
Date: Fri, 15 Feb 2013 16:09:40 +0100 [thread overview]
Message-ID: <20130215150940.GA31861@redhat.com> (raw)
In-Reply-To: <20130215145648.GE8193@moon>
On 02/15, Cyrill Gorcunov wrote:
>
> > strace needs to get that data on every syscall entry in the traced process.
> > Doing open/read/close on every syscall entry is going to slow it down a lot.
>
> Don't you need to read it only once when strace is attached? Compat flag can't
> be arbitrary dropped when program executes, no?
TS_COMPAT is set/cleared every time a 64bit task does int80.
I guess you need TIF_IA32, not TS_COMPAT, for c/r.
Oleg.
next prev parent reply other threads:[~2013-02-15 15:11 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-14 13:17 [PATCH] x86: make PTRACE_GETREGSET return 32-bit regs if 64-bit process entered kernel with int 80 Denys Vlasenko
2013-02-14 15:00 ` Oleg Nesterov
2013-02-14 16:26 ` Denys Vlasenko
2013-02-14 18:05 ` H. Peter Anvin
2013-02-14 19:18 ` Oleg Nesterov
2013-02-14 19:21 ` H. Peter Anvin
2013-02-14 20:55 ` Cyrill Gorcunov
2013-02-15 14:50 ` Denys Vlasenko
2013-02-15 14:56 ` Cyrill Gorcunov
2013-02-15 15:09 ` Oleg Nesterov [this message]
2013-02-15 15:16 ` Cyrill Gorcunov
2013-02-15 15:42 ` Denys Vlasenko
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