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To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>, Ingo Molnar <mingo@elte.hu>,         Ananth N Mavinakayanahalli <ananth@in.ibm.com>,         lkml <linux-kernel@vger.kernel.org>,         systemtap <systemtap@sources.redhat.com>,         DLE <dle-develop@lists.sourceforge.net>,         Jim Keniston <jkenisto@us.ibm.com>,         Srikar Dronamraju <srikar@linux.vnet.ibm.com>,         Christoph Hellwig <hch@infradead.org>,         Steven Rostedt <rostedt@goodmis.org>, "H. Peter Anvin" <hpa@zytor.com>,         Anders Kaseorg <andersk@ksplice.com>, Tim Abbott <tabbott@ksplice.com>,         Andi Kleen <andi@firstfloor.org>, Jason Baron <jbaron@redhat.com>,         Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: Re: [PATCH -tip v5 06/10] kprobes/x86: Cleanup save/restore 	registers
References: <20091123232115.22071.71558.stgit@dhcp-100-2-132.bos.redhat.com> 	<20091123232204.22071.60562.stgit@dhcp-100-2-132.bos.redhat.com> 	<20091124025115.GB6752@nowhere>
From: fche@redhat.com (Frank Ch. Eigler)
Date: Tue, 24 Nov 2009 15:40:00 -0000
In-Reply-To: <20091124025115.GB6752@nowhere> (Frederic Weisbecker's message of "Tue, 24 Nov 2009 03:51:17 +0100")
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Frederic Weisbecker <fweisbec@gmail.com> writes:

> [...]
>> +#define SAVE_REGS_STRING		\
>> +#define RESTORE_REGS_STRING		\
>
> BTW, do you really need to push/pop every registers
> before/after calling a probe handler?

It's part of the definition of a kprobe, that a populated
pt_regs* value is passed.  Clients can rely on that in order
to access registers etc.

- FChE