From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA12DC43460 for ; Wed, 31 Mar 2021 14:12:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96A8160FE8 for ; Wed, 31 Mar 2021 14:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235917AbhCaOM1 (ORCPT ); Wed, 31 Mar 2021 10:12:27 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:59031 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235959AbhCaOMO (ORCPT ); Wed, 31 Mar 2021 10:12:14 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4F9Stg5l9Cz9tyxm; Wed, 31 Mar 2021 16:12:11 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id 1HGotb5q2Doe; Wed, 31 Mar 2021 16:12:11 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4F9Stg4vQFz9v328; Wed, 31 Mar 2021 16:12:11 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id C8AE38B828; Wed, 31 Mar 2021 16:12:12 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id vMVCrlZfARoR; Wed, 31 Mar 2021 16:12:12 +0200 (CEST) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 363738B80D; Wed, 31 Mar 2021 16:12:12 +0200 (CEST) Subject: Re: [PATCH] powerpc/8xx: Load modules closer to kernel text To: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Jordan Niethe References: <87czvf788t.fsf@mpe.ellerman.id.au> From: Christophe Leroy Message-ID: Date: Wed, 31 Mar 2021 16:12:06 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 MIME-Version: 1.0 In-Reply-To: <87czvf788t.fsf@mpe.ellerman.id.au> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 31/03/2021 à 15:39, Michael Ellerman a écrit : > Christophe Leroy writes: >> On the 8xx, TASK_SIZE is 0x80000000. The space between TASK_SIZE and >> PAGE_OFFSET is not used. >> >> Use it to load modules in order to minimise the distance between >> kernel text and modules and avoid trampolines in modules to access >> kernel functions or other module functions. >> >> Define a 16Mbytes area for modules, that's more than enough. > > 16MB seems kind of small. > > At least on 64-bit we could potentially have hundreds of MBs of modules. > Well, with a 16 MB kernel and 16 MB modules, my board is full :) Even on the more recent board that has 128 MB, I don't expect more than a few MBs of modules in addition to the kernel which is approx 8M. But ok, I'll do something more generic, though it will conflict with Jordan's series. Christophe