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From: "Jan Beulich" <jbeulich@suse.com>
To: <luto@amacapital.net>
Cc: <chenggang.qcg@alibaba-inc.com>, <chenggang.qin@gmail.com>,
	<dsahern@gmail.com>, <namhyung@gmail.com>, <efault@gmx.de>,
	<eranian@google.com>, <peterz@infradead.org>,
	<fengguang.wu@intel.com>, <yanmin.zhang@intel.com>,
	<akpm@linux-foundation.org>, <arjan@linux.intel.com>,
	<jolsa@redhat.com>, <mingo@redhat.com>, <paulus@samba.org>,
	<chenggang.qcg@taobao.com>, <linux-kernel@vger.kernel.org>
Subject: Re: 答复:[PATCH] perf core: Use KSTK_ESP() instead of pt_regs->sp while output user regs
Date: Mon, 05 Jan 2015 08:47:17 +0000	[thread overview]
Message-ID: <54AA4F9502000078000C4C46@mail.emea.novell.com> (raw)
In-Reply-To: <CALCETrUbEpTuQKiUPKeT54nFSwDQh9uA2QHLXsZeTbLrMsqxoA@mail.gmail.com>

>>> Andy Lutomirski <luto@amacapital.net> 01/02/15 7:03 PM >>>
>On Jan 2, 2015 8:11 AM, "Jan Beulich" <jbeulich@suse.com> wrote:
>> Trying to guess what you mean by "this": A stack switch gets expressed by
>> CFI annotations just like any other frame pointer adjustments. See for example
>> the CFI_DEF_CFA_REGISTER use in the SAVE_ARGS_IRQ macro.
>>
>> If that wasn't your question, please be more precise.
>
>Sorry, my question was vague.
>
>Is there any way to consume these annotations at runtime in the
>kernel?  The goal would be for perf's NMI handler to consume the CFI
>data to figure out the userspace registers.  I'm guessing that the
>answer might be no, because we seem to be compiling with
>-fno-asynchronous-unwind-tables and we don't seem to be putting any
>.eh_frame stuff into the final kernel image.
>
>I had thought that someone implemented runtime DWARF unwinding, though.

Yes, we do have such code in our kernels, but Linus continues to veto it going
into his tree.

Jan


  reply	other threads:[~2015-01-05  8:47 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-23  6:22 [PATCH] " root
2014-12-23  8:30 ` Andy Lutomirski
     [not found] ` <c027bde0-5f4f-441f-8d45-3e7f6f702231@alibaba-inc.com>
2014-12-25 15:48   ` 答复:[PATCH] " Andy Lutomirski
2014-12-25 16:21     ` Andy Lutomirski
2014-12-30 19:03     ` Peter Zijlstra
2014-12-30 23:29       ` Andy Lutomirski
2014-12-31  2:00         ` Andy Lutomirski
2015-01-02 16:11           ` Jan Beulich
2015-01-02 18:03             ` Andy Lutomirski
2015-01-05  8:47               ` Jan Beulich [this message]
2015-01-04 16:10       ` Jiri Olsa
2015-01-04 17:18         ` Andy Lutomirski
2015-01-04 17:41           ` Jiri Olsa
2015-01-04 18:36             ` [PATCH 0/2] perf: Improve user regs sampling Andy Lutomirski
2015-01-04 18:36               ` [PATCH 1/2] perf: Move task_pt_regs sampling into arch code Andy Lutomirski
2015-01-05 14:07                 ` Peter Zijlstra
2015-01-05 16:13                   ` Andy Lutomirski
2015-01-05 16:44                     ` Peter Zijlstra
2015-01-05 18:28                       ` Andy Lutomirski
2015-01-09 12:32                 ` [tip:perf/urgent] " tip-bot for Andy Lutomirski
2015-01-04 18:36               ` [PATCH 2/2] x86_64, perf: Improve user regs sampling Andy Lutomirski
2015-01-09 12:32                 ` [tip:perf/urgent] perf/x86_64: " tip-bot for Andy Lutomirski
2015-01-05 10:46               ` [PATCH 0/2] perf: " Jiri Olsa

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