From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id A258CB6EEB for ; Tue, 5 Jun 2012 08:01:23 +1000 (EST) Message-ID: <1338847242.7150.83.camel@pasglop> Subject: Re: kernel panic during kernel module load (powerpc specific part) From: Benjamin Herrenschmidt To: Gabriel Paubert Date: Tue, 05 Jun 2012 08:00:42 +1000 In-Reply-To: <20120604110305.GA16707@visitor2.iram.es> References: <4FC62FB9.8010701@nsn.com> <1338420242.27402.2.camel@concordia> <192298D25D96A042975E372855100DB70FEA87@039-SN2MPN1-011.039d.mgd.msft.net> <20120531110439.GA17373@visitor2.iram.es> <1338542315.16119.50.camel@pasglop> <192298D25D96A042975E372855100DB70FF0E2@039-SN2MPN1-011.039d.mgd.msft.net> <20120604110305.GA16707@visitor2.iram.es> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: Wrobel Heinz-R39252 , Michael Ellerman , Steffen Rumler , "linuxppc-dev@lists.ozlabs.org" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 2012-06-04 at 13:03 +0200, Gabriel Paubert wrote: > There is no conflict to the ABI. These functions are supposed to be > directly reachable from whatever code > section may need them. > > Now I have a question: how did you get the need for this? > > None of my kernels uses them: > - if I compile with -O2, the compiler simply expands epilogue and > prologue to series of lwz and stw > - if I compile with -Os, the compiler generates lmw/stmw which give > the smallest possible cache footprint > > Neither did I find a single reference to these functions in several > systems that I grepped for. Newer gcc's ... even worse, with -Os, it does it for a single register spill afaik. At least that's how I hit it with grub2 using whatever gcc is in fc17. Cheers, Ben.