Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753003Ab2FEU5d (ORCPT ); Tue, 5 Jun 2012 16:57:33 -0400 Received: from mail-gh0-f174.google.com ([209.85.160.174]:56420 "EHLO mail-gh0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752924Ab2FEU5a convert rfc822-to-8bit (ORCPT ); Tue, 5 Jun 2012 16:57:30 -0400 MIME-Version: 1.0 In-Reply-To: <20120530140444.GA10543@frolo.macqel> References: <1338327216-15309-1-git-send-email-geert@linux-m68k.org> <20120530102226.GA28628@frolo.macqel> <20120530140444.GA10543@frolo.macqel> Date: Tue, 5 Jun 2012 22:57:29 +0200 X-Google-Sender-Auth: lTgex80yLmK_O041XXmKWjZbLds Message-ID: Subject: Re: [PATCH] m68k: Use generic strncpy_from_user(), strlen_user(), and strnlen_user() From: Geert Uytterhoeven To: Philippe De Muyter , Greg Ungerer Cc: linux-m68k@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2675 Lines: 75 On Wed, May 30, 2012 at 4:04 PM, Philippe De Muyter wrote: > On Wed, May 30, 2012 at 01:20:02PM +0200, Geert Uytterhoeven wrote: >> On Wed, May 30, 2012 at 12:22 PM, Philippe De Muyter wrote: >> > On Tue, May 29, 2012 at 11:33:36PM +0200, Geert Uytterhoeven wrote: >> >> Signed-off-by: Geert Uytterhoeven >> >> --- >> >> Do we also want >> >> >> >>     select HAVE_EFFICIENT_UNALIGNED_ACCESS if (!COLDFIRE && !M68000) >> > >> > Sorry, I did not follow what happened to unaligned accesses, but >> > CPU32 family (at least 68340) crashes on unaligned accesses. >> >> We don't seem to have CONFIG_M68340 in arch/m68k/Kconfig.cpu? > > I have a local port here (but based on an ancient linux kernel, 2.6.2 IIRC) > >> But Freescale's website confirms both 68340 and 68360 are CPU32. >> >> arch/m68k/include/asm/unaligned.h assumes CPU32 (CONFIG_MCPU32) >> can do unaligned accesses: > > That's not true.  Accessing a 16- or 32-bit word at an odd address > with a 68340 generates an Address Error Exception.  I remember > discovering a bug in the ppp kernel code because of that. > >> >> #if defined(CONFIG_COLDFIRE) || defined(CONFIG_M68000) >> #include >> #include >> #include >> >> #define get_unaligned   __get_unaligned_be >> #define put_unaligned   __put_unaligned_be >> >> #else >> /* >>  * The m68k can do unaligned accesses itself. >>  */ >> #include >> #include >> >> #define get_unaligned   __get_unaligned_be >> #define put_unaligned   __put_unaligned_be >> >> #endif >> >> Is this wrong? > > I can't tell from reading just the lines above, but I think one should add > "|| defined(CONFIG_MCPU32)" at the end of the if condition. Greg? If more CPUs cannot handle unaligned accesses, I propose to add CONFIG_CPU_HAS_NO_UNALIGNED. > I also think that the Coldfire 5272 can do unaligned accesses, but I > cannot test that at the moment. Gr{oetje,eeting}s,                         Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.                                 -- Linus Torvalds -- 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/