From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Simek Subject: Re: [PATCH V3] asm-generic: add a generic uaccess.h Date: Fri, 01 May 2009 16:11:27 +0200 Message-ID: <49FB030F.8060300@monstr.eu> References: <200905011513.25344.arnd@arndb.de> <49FAFD63.2080102@monstr.eu> <200905011606.05319.arnd@arndb.de> Reply-To: monstr@monstr.eu Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-fx0-f158.google.com ([209.85.220.158]:43599 "EHLO mail-fx0-f158.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751539AbZEAOLa (ORCPT ); Fri, 1 May 2009 10:11:30 -0400 In-Reply-To: <200905011606.05319.arnd@arndb.de> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: linux-arch@vger.kernel.org, Remis Lima Baima , linux-kernel@vger.kernel.org, Russell King Arnd Bergmann wrote: > On Friday 01 May 2009, Michal Simek wrote: >> Arnd Bergmann wrote: >>> + >>> +#include >>> + >>> +#ifndef get_fs >>> +#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) >> one line above -> get_fs could be defined in different space >> and this arch could use MAKE_MM_SEG too -> for example powerpc. > > I don't think I understand what you are trying to tell me. > How do you think this should look? I meant move MAKE_MM_SEG macro to this position because this macro could be use with arch which define different get_fs. #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) #ifndef get_fs ... > >>> + >>> +#define VERIFY_READ 0 >>> +#define VERIFY_WRITE 1 >>> + >> >> Not sure if any arch do READ/WRITE check but if yes. > > I could not find any architecture using it either, but the > API is defined this way. > >> #ifndef access_ok >> >>> +#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size)) >> #endif > > right, will change. > >>> + >>> +/* >>> + * The architecture should really override this if possible, at least >>> + * doing a check on the get_fs() >>> + */ >> If they should really override it but why write it here. > > Mostly for documentation purposes, so that an architecture maintainer > can copy the prototype. I see the asm-generic headers as both fallbacks > for architectures and as templates of what should be implemented. > >>> +#define get_user(x, ptr) \ >>> +({ \ >>> + might_sleep(); \ >>> + __access_ok(ptr, sizeof (*ptr)) ? \ >>> + __get_user(x, ptr) : \ >>> + -EFAULT; \ >>> +}) >> I am getting here (for put_user macro too) any error on noMMU. :-( > > What kind of error do you see? System is getting crazy with -> I am debugging it. > >>> +static inline long >>> +strncpy_from_user(char *dst, const char __user *src, long count) >>> +{ >>> + if (!__access_ok(src, 1)) >>> + return -EFAULT; >>> + return __strncpy_from_user(dst, src, count); >>> +} >> Is it a good place to add might_sleep() and unlikely(+ some other cases) too? >> We have almost the same code. > > Yes, I think so. The unlikely() can probably go into __access_ok() though, > so we don't have to write it every time. ok Michal > > Arnd <>< -- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854