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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 7CFD6C4646F for ; Thu, 4 Mar 2021 00:49:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 645FD64F6D for ; Thu, 4 Mar 2021 00:49:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239338AbhCDAtR (ORCPT ); Wed, 3 Mar 2021 19:49:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:45206 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240239AbhCCR3b (ORCPT ); Wed, 3 Mar 2021 12:29:31 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1AD96600EF; Wed, 3 Mar 2021 17:28:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614792496; bh=zlg3djBmpPQX9HA9Tio/KvTAc3gzFSUjPMEmR7Drzyg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nSQTrq7mqSrGIDFdtUatUCDfw1IC6EyoOVr0Uj3b1E0wymegPLztI2ED6vcxu5C85 UY60ZVdYnSuXJN3JzhG55Piik7aZ8B9E+K1A+FSoDiagqWM65C/fZI81O0MtFX5GkU yUft1a2F5wt6kV7eIsuS4bnBkC4qpzlxDS5+/Li2Xdkmu1wtESzUphUjRgv1i2DuQP L86JZ8VksAPpPB0GZMXfG7aFYiXs+x+Mlfg8tgnWmuDM5/65uHXjSYTApptiVRqnVP DKdLG5OBDF3pbNQHv3Ku+COBJ56gx+Bk0mQOP6S6LMBjqA63x+sYmeaty89WZBN7Tk nqvxMJ9ADAITw== Date: Wed, 3 Mar 2021 17:28:10 +0000 From: Will Deacon To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , danielwa@cisco.com, robh@kernel.org, daniel@gimpelevich.san-francisco.ca.us, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH v2 1/7] cmdline: Add generic function to build command line. Message-ID: <20210303172810.GA19713@willie-the-truck> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Tue, Mar 02, 2021 at 05:25:17PM +0000, Christophe Leroy wrote: > This code provides architectures with a way to build command line > based on what is built in the kernel and what is handed over by the > bootloader, based on selected compile-time options. > > Signed-off-by: Christophe Leroy > --- > include/linux/cmdline.h | 62 +++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 62 insertions(+) > create mode 100644 include/linux/cmdline.h > > diff --git a/include/linux/cmdline.h b/include/linux/cmdline.h > new file mode 100644 > index 000000000000..ae3610bb0ee2 > --- /dev/null > +++ b/include/linux/cmdline.h > @@ -0,0 +1,62 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _LINUX_CMDLINE_H > +#define _LINUX_CMDLINE_H > + > +static __always_inline size_t cmdline_strlen(const char *s) > +{ > + const char *sc; > + > + for (sc = s; *sc != '\0'; ++sc) > + ; /* nothing */ > + return sc - s; > +} > + > +static __always_inline size_t cmdline_strlcat(char *dest, const char *src, size_t count) > +{ > + size_t dsize = cmdline_strlen(dest); > + size_t len = cmdline_strlen(src); > + size_t res = dsize + len; > + > + /* This would be a bug */ > + if (dsize >= count) > + return count; > + > + dest += dsize; > + count -= dsize; > + if (len >= count) > + len = count - 1; > + memcpy(dest, src, len); > + dest[len] = 0; > + return res; > +} Why are these needed instead of using strlen and strlcat directly? > +/* > + * This function will append a builtin command line to the command > + * line provided by the bootloader. Kconfig options can be used to alter > + * the behavior of this builtin command line. > + * @dest: The destination of the final appended/prepended string. > + * @src: The starting string or NULL if there isn't one. Must not equal dest. > + * @length: the length of dest buffer. > + */ > +static __always_inline void cmdline_build(char *dest, const char *src, size_t length) > +{ > + if (length <= 0) > + return; > + > + dest[0] = 0; > + > +#ifdef CONFIG_CMDLINE > + if (IS_ENABLED(CONFIG_CMDLINE_FORCE) || !src || !src[0]) { > + cmdline_strlcat(dest, CONFIG_CMDLINE, length); > + return; > + } > +#endif CONFIG_CMDLINE_FORCE implies CONFIG_CMDLINE, and even if it didn't, CONFIG_CMDLINE is at worst an empty string. Can you drop the #ifdef? > + if (dest != src) > + cmdline_strlcat(dest, src, length); > +#ifdef CONFIG_CMDLINE > + if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) && sizeof(CONFIG_CMDLINE) > 1) > + cmdline_strlcat(dest, " " CONFIG_CMDLINE, length); > +#endif Likewise, but also I'm not sure why the sizeof() is required. Will