From: David Daney <david.daney@cavium.com>
To: Joe Buehler <aspam@cox.net>
Cc: linux-mips@linux-mips.org
Subject: Re: using mprotect to write to .text
Date: Tue, 11 Oct 2011 09:36:49 -0700 [thread overview]
Message-ID: <4E9470A1.8020309@cavium.com> (raw)
In-Reply-To: <loom.20111010T215444-70@post.gmane.org>
On 10/10/2011 01:02 PM, Joe Buehler wrote:
> I intend to use mprotect in a running binary to allow it to modify its .text
> section. The detailed behavior of mprotect for a multithreaded program on SMP
> hardware is not documented as far as I can tell.
It is well documented. What is not well defined is what happens if you
modify the code and then try to execute it.
>
> Can I depend on the LINUX mprotect call to take care of icache flushing,
> handling of hazards, etc.?
No, it does nothing of the sort. You need cacheflush() for that.
> I am using Octeon CN5650 on 2.6.21.7 and 2.6.27.7 if
> it matters.
It doesn't really matter.
What you need is something like:
#include <sys/cachectl.h>
.
.
.
cacheflush(location, size, ICACHE);
.
.
.
David Daney
next prev parent reply other threads:[~2011-10-11 16:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-10 20:02 using mprotect to write to .text Joe Buehler
2011-10-11 16:36 ` David Daney [this message]
2011-10-11 17:31 ` Joe Buehler
2011-10-11 18:06 ` David Daney
2011-10-11 18:35 ` Joe Buehler
2011-10-11 18:43 ` David Daney
2011-10-11 23:17 ` Ralf Baechle
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