From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Dunlap Subject: Re: Section mismatch in parainstructions Date: Sun, 10 Dec 2006 18:34:41 -0800 Message-ID: <20061210183441.86785fee.randy.dunlap@oracle.com> References: <20061210155821.d2c5dfa5.randy.dunlap@oracle.com> <457CA915.1040109@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <457CA915.1040109@goop.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.osdl.org Errors-To: virtualization-bounces@lists.osdl.org To: Jeremy Fitzhardinge Cc: akpm , virtualization@lists.osdl.org, sam@ravnborg.org List-Id: virtualization@lists.linuxfoundation.org On Sun, 10 Dec 2006 16:40:53 -0800 Jeremy Fitzhardinge wrote: > Randy Dunlap wrote: > > Is it OK for section .parainstructions to reference > > exit.text? > > > > I'm seeing: > > > > WARNING: drivers/net/hamradio/scc.o - Section mismatch: reference to .e= xit.text: from .parainstructions after '' (at offset 0x0) > > WARNING: drivers/net/hamradio/scc.o - Section mismatch: reference to .e= xit.text: from .parainstructions after '' (at offset 0x8) > > > > If that's OK, we need a small patch to modpost, as below. > > = > = > What are the semantics of .exit.text? In principle a paravirtualized > instruction can appear anywhere, so I think these warnings are bogus. = > The only concern is if one of these sections disappears before the > paravirt_ops instruction substitution happens. Good question. I don't see much doc on that subject. Rusty could probably answer that better than me. Something like this: .exit.text section(s) can be discarded from built-in (non-modular) code (or not even loaded at all). .exit.text section(s) in modules is only loaded when CONFIG_MODULE_UNLOAD=3Dy. so what are the .parainstructions text sections for? Are they for replacing code instructions based on some condition(s)? (like self-modifying code? ) --- ~Randy