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From: Andi Kleen <andi@firstfloor.org>
To: Jun Wang <junwang123@gmail.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: access function parameters with DWARF-less perf probing
Date: Wed, 23 Apr 2014 22:21:07 -0700	[thread overview]
Message-ID: <87iopzb8vw.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <CANHDG4btxwQxGme+TwWYhPVEKSwyHA_C3fVxNuaFJOrzGYOyCA@mail.gmail.com> (Jun Wang's message of "Tue, 22 Apr 2014 10:31:34 -0700")

Jun Wang <junwang123@gmail.com> writes:

> Hi Everyone,
>
> With systemTap, in the absence of debugging information (DWARF), one
> can access function parameters using (positional) numbers. Can the
> same be done with `perf`?
> Why? I'm trying to capture variables in a kernel function but I don't
> have an good perf with DWARF support and there is are significant
> challenges to build one due to the relatively old distro.

You can specify the registers according to the ABI. 
di = 1. arg, si = 2nd arg etc.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only

  reply	other threads:[~2014-04-24  5:21 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-22 17:31 access function parameters with DWARF-less perf probing Jun Wang
2014-04-24  5:21 ` Andi Kleen [this message]
2014-04-24 14:12   ` David Ahern
2014-04-30 18:47     ` Jun Wang
2014-04-29 15:48   ` Milian Wolff

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