Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761750AbYGOOYb (ORCPT ); Tue, 15 Jul 2008 10:24:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761485AbYGOOYJ (ORCPT ); Tue, 15 Jul 2008 10:24:09 -0400 Received: from rn-out-0910.google.com ([64.233.170.188]:56796 "EHLO rn-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761468AbYGOOYH (ORCPT ); Tue, 15 Jul 2008 10:24:07 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=l/uH/eRgGWxN2AY//alJ+B4y3WStSP/n8I0iYoX2ZNuMYke0qbuDxykuyq0/pBMnPQ pDSv8iza0CFWYz/oU3EZYLLqDqFDmRQv/nEidwRmKp2ZED2A3+AIMv0KPaoQHgng5SCd pDProkte5LkXDt1Qz2UsV4A1pQT+WGzmQwXgk= Message-ID: <8bd0f97a0807150724x8f7095dl9b5d2e203053223f@mail.gmail.com> Date: Tue, 15 Jul 2008 10:24:05 -0400 From: "Mike Frysinger" To: "Jeremy Fitzhardinge" Subject: Re: linux-next: 1ea0704e (ptep_modify_prot transaction abstraction) breaks no-mmu Cc: LKML In-Reply-To: <486CF610.7000905@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <8bd0f97a0807030638g5eb8f0eavd740e990b1cdf1c5@mail.gmail.com> <486CF610.7000905@goop.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1775 Lines: 39 On Thu, Jul 3, 2008 at 11:53 AM, Jeremy Fitzhardinge wrote: > Mike Frysinger wrote: >> the functions added to asm-generic/pgtable.h are only used by >> mm/mprotect.c (a MMU-only file), but they were not added inside of the >> CONFIG_MMU ifdef block. since the functions rely on things inside of >> CONFIG_MMU (the lines just above in pgtable.h), we get build failure >> on all no-mmu setups: >> CC init/main.o >> In file included from include/asm/pgtable.h:94, >> from include/linux/mm.h:39, >> from include/asm/dma.h:39, >> from include/linux/bootmem.h:8, >> from init/main.c:27: >> include/asm-generic/pgtable.h: In function '__ptep_modify_prot_start': >> include/asm-generic/pgtable.h:210: error: implicit declaration of >> function 'ptep_get_and_clear' >> include/asm-generic/pgtable.h:210: error: incompatible types in return >> make[1]: *** [init/main.o] Error 1 >> make: *** [init/main.o] Error 2 > > Uh, OK. What does mprotect do on a nommu system? it depends on the port. by default, i'm pretty sure mprotect on all nommu systems are realistically pretty much noops. the Blackfin can do real protection (CONFIG_MPU), but with significant performance degradation (since the page fault handler is not in hardware nor hardware assisted in any way). > Would it be sufficient to > move the definitions of __ptep_modify_prot_start/commit out of a CONFIG_MMU > block, or provide separate no-op versions? simply move them into CONFIG_MMU for now -mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/