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Re: [PATCH] Linux Kernel Markers
- From: Andi Kleen <ak at suse dot de>
- To: Ingo Molnar <mingo at elte dot hu>
- Cc: Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>, "Frank Ch. Eigler" <fche at redhat dot com>, Paul Mundt <lethal at linux-sh dot org>, linux-kernel <linux-kernel at vger dot kernel dot org>, Jes Sorensen <jes at sgi dot com>, Andrew Morton <akpm at osdl dot org>, Tom Zanussi <zanussi at us dot ibm dot com>, Richard J Moore <richardj_moore at uk dot ibm dot com>, Michel Dagenais <michel dot dagenais at polymtl dot ca>, Christoph Hellwig <hch at infradead dot org>, Greg Kroah-Hartman <gregkh at suse dot de>, Thomas Gleixner <tglx at linutronix dot de>, William Cohen <wcohen at redhat dot com>, ltt-dev at shafik dot org, systemtap at sources dot redhat dot com, Alan Cox <alan at lxorguk dot ukuu dot org dot uk>, mbligh at google dot com
- Date: 20 Sep 2006 13:19:29 +0200
- Subject: Re: [PATCH] Linux Kernel Markers
- References: <20060918234502.GA197@Krystal> <20060919081124.GA30394@elte.hu> <451008AC.6030006@google.com> <20060919153107.GA16414@elte.hu>
Ingo Molnar <mingo@elte.hu> writes:
>
> yeah, this would be nice - if it werent it for function pointers, and if
> all kernel functions were relocatable. But if you can think of a method
> to do this, it would be nice.
x86-64 did it for some time statically to replace mem copies and some other
functions. Basically it just patches the beginning of the other function
to a jump. However this assumes that the code doesn't contain absolute addresses
(e.g. no switches). In the x86-64 it's easy because only assembly functions
are threated this way.
-Andi