From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/9609 Path: news.gmane.org!not-for-mail From: Masanori Ogino Newsgroups: gmane.linux.lib.musl.general Subject: Re: musl without atomic instructions? Date: Mon, 14 Mar 2016 11:55:15 +0900 Message-ID: References: <20160313002140.GG9349@brightrain.aerifal.cx> <20160314021357.GJ9349@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1457924132 11798 80.91.229.3 (14 Mar 2016 02:55:32 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 14 Mar 2016 02:55:32 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-9622-gllmg-musl=m.gmane.org@lists.openwall.com Mon Mar 14 03:55:30 2016 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1afIfK-0008O0-9C for gllmg-musl@m.gmane.org; Mon, 14 Mar 2016 03:55:30 +0100 Original-Received: (qmail 16124 invoked by uid 550); 14 Mar 2016 02:55:27 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 16100 invoked from network); 14 Mar 2016 02:55:26 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to; bh=A68JGRTkQrl9Qkp2XYLc4Y0N+lXBKOEO7tl4LsHM8fE=; b=FZS1r8CS7r7D+z/sDw+bBosiyNGk1IBWotIL0umeJYTGmYuLtb2CxEbuEpIf2w0N5A 2ZLIrFrczsFgspjKtxZLW63mWFaY/P/WEh2XIMYU/WZiFi9E+tYIEZ7cwklVbAgWm4qj xO0mO83UVp5gZe3B6Ahl2nnnowb1Kt8R3qIqFUZe8Jpx3mcnnI1sFHMy8hee1QwUsARL V4wdTpoeWQ/wvzRwAJ7cCI9WJo1Fumjxi3k1aHtmGF+k1sQBKbnzrAIfG9oBcjSaVVzj NgD+uVQcLG40PGeA+28HZsLTpy5cszxLQqbvLWdvfwRtRbAG/mGwvxnaaX31mmbq76Wc lunA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to; bh=A68JGRTkQrl9Qkp2XYLc4Y0N+lXBKOEO7tl4LsHM8fE=; b=lyFGtxB7dp2zwKErDFg++ujWVESxcwgH0gqT1XlAkbIBswL9jULw53neBlX3cMG9lA lfzt7FhJREalcvWN9QyPetz/WrGqeNnpeA1H0HzHBsLG1ylwDzqcOm3HFCHA15QdNBrs QD8n7oh6VOSLPXos97YVCldRk69HMTYqKlpvd9FCYQZdgLy5deNtIlPlr91/+QRKcknH O2K4YEEdZ/yc3SyEto/G8V7X6mTOqenezuCDbWygFKl/6klkgsiFLwlBzjwYUbqptHTS cNbMict770w46BL2f+juzB3Z9qmh7JHbg1VDp/ViqXaIsqgCKOXlddkYCN3JLwD5FNOh vjjA== X-Gm-Message-State: AD7BkJLbHRo45DOS2JtzHCFJFHE/tMKjRYI8QMfeDOvwiuZKkVIga7fpfXQlSOMfI+3MXx/LfnV6Bbqb+Z3P4g== X-Received: by 10.182.102.103 with SMTP id fn7mr13173573obb.83.1457924115107; Sun, 13 Mar 2016 19:55:15 -0700 (PDT) Original-Sender: masanoriogino@gmail.com In-Reply-To: <20160314021357.GJ9349@brightrain.aerifal.cx> X-Google-Sender-Auth: 1_G_oPnhR6YeNQBSrpkJXuRyRDA Xref: news.gmane.org gmane.linux.lib.musl.general:9609 Archived-At: 2016-03-14 11:13 GMT+09:00 Rich Felker : > IMO a vdso function should be added that makes the syscall, rather > than having libc call the syscall directly; this would allow the > kernel to automatically provide a better implementation in the future > without the need to rebuild applications. Using a syscall for this is > very slow. Working with kernel people to propose such a thing (or even > implementing it and submitting kernel patches) is certainly one option > for something to add to a GSoC project proposal to make it more > substantial. Well, it seems that I don't really understand vDSO. My current understanding is, vDSO make it possible that: 1. programs targeting without-A processors use syscalls on without-A processors, and 2. the programs use atomic instructions on with-A processors. (no interruption, no context switching!) (3. programs targeting with-A processors runs normally, without calling such vDSO function) Is it correct? If so, it would be really nice. -- Masanori Ogino