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=-0.3 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 3D3A8C3A59E for ; Wed, 21 Aug 2019 13:15:09 +0000 (UTC) Received: from krantz.zx2c4.com (krantz.zx2c4.com [192.95.5.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 903DA2082F for ; Wed, 21 Aug 2019 13:15:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rcSZRUDS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 903DA2082F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=wireguard-bounces@lists.zx2c4.com Received: from krantz.zx2c4.com (localhost [IPv6:::1]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 028a03c0; Wed, 21 Aug 2019 13:15:07 +0000 (UTC) Received: from krantz.zx2c4.com (localhost [127.0.0.1]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 5915a077 for ; Wed, 21 Aug 2019 13:15:05 +0000 (UTC) Received: from mail-qt1-x82f.google.com (mail-qt1-x82f.google.com [IPv6:2607:f8b0:4864:20::82f]) by krantz.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 159cb403 for ; Wed, 21 Aug 2019 13:15:05 +0000 (UTC) Received: by mail-qt1-x82f.google.com with SMTP id t12so2910865qtp.9 for ; Wed, 21 Aug 2019 06:15:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=n5LLhYdefd4TmYf9edY64Z5+29OTZhnlX7F7jTt4+XA=; b=rcSZRUDSWA4GJ3rbquyjwpcmDXMrj86FagELPPQtCq4yza6NIkWxwF9RVd254TrEpb UuY7y7bYSeisDoYuZTfvoWZuS2fLGcyMR+pnnsNTnHqhuoOCEbhCeoKxISCbQuA1AbvO 6vyzwMw0GQt28Cmtq7iDbvHJyMOrJKSFyflhNCOQJ5RWHvb+ZR3k3upv1wtfWPUYaRY8 8Aehk2XA4RpIlnT3Ik9kb6ZudPzdJUqQS737cKtC5nBccaIWcksm+i46Im0HG+ldV+vd dNu0kjHpuf0a9Ont7OQYWKAjV14W5KbGVIK9NqFC0IFfCOzwgUuqvo2BIXWmBH0lV8q+ nFAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=n5LLhYdefd4TmYf9edY64Z5+29OTZhnlX7F7jTt4+XA=; b=XRdRSqlIqNQ6+WTacP9XAxRF+TqrjTxeKmSMVXoD2jLg6KPb6cEcD4smBLJwJtoGT4 43Msw/lycca+kXPhHS/9hvZZ5mTdPV4p6+cfaZ6LJZH/MBhyXJd9URqnGiMzF4U9Jj0Z qZNzB8vJ/i2Kw5zB4IDeZvR102186eAkfOKg0L3MdPtLC7dpDSASLNDjUixQnQCi3kz8 1ImqM36h77DI+CbU3KBanwMmQllL7X6I9dSu4h3joo0V4Dvdbnax5mE9j37PBKWDvS0S Fyh2tdNVuh8dyWLkLL5b9nWreIj4TwwyN/ID3XzpbGFUslcKGJkdgkOwDlP0ZmaRV/o+ qaEA== X-Gm-Message-State: APjAAAXOM54vtc3cDVLk1GWHaOonMt3wDu5GYbNDw6CnI0pL8uOe12XN p44qdOkEhjU3j9Q7nuEC1PEN2NHY+VFNIYzKwW9q3PuI X-Google-Smtp-Source: APXvYqzjNrZffW0y/gY9zV4hA443kMbsZDFjU+wpJTwWG+xeqdI+5d9aP3gtDRGvrDbImIHQ6FJ2rer5cxVdl12EXF0= X-Received: by 2002:a0c:fcd2:: with SMTP id i18mr4556734qvq.223.1566393304634; Wed, 21 Aug 2019 06:15:04 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Lev Stipakov Date: Wed, 21 Aug 2019 16:14:53 +0300 Message-ID: Subject: Re: Volatile in Wintun To: "Jason A. Donenfeld" Cc: WireGuard mailing list X-BeenThere: wireguard@lists.zx2c4.com X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development discussion of WireGuard List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============4880338645647588556==" Errors-To: wireguard-bounces@lists.zx2c4.com Sender: "WireGuard" --===============4880338645647588556== Content-Type: multipart/alternative; boundary="000000000000805e7f0590a05cca" --000000000000805e7f0590a05cca Content-Type: text/plain; charset="UTF-8" Hi Jason, we don't assume that volatile implies a memory > barrier. We could probably switch to /volatile:iso. > Does it mean that hardware reordering like writes reordered after reads on x86/amd64 and everything else on ARM are not considered to be a problem? Should barriers generated by WaitForSingleObject / SetEvent be enough? -- -Lev --000000000000805e7f0590a05cca Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi Jason,

we don&#= 39;t assume that volatile implies a memory
barrier. We could probably switch to /volatile:iso.

Does it mean that hardware reordering lik= e writes reordered after reads
on x86/amd64 and everything else on ARM = are not considered=C2=A0to be a problem?

Should ba= rriers generated by WaitForSingleObject / SetEvent be enough?

--
-Lev
--000000000000805e7f0590a05cca-- --===============4880338645647588556== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ WireGuard mailing list WireGuard@lists.zx2c4.com https://lists.zx2c4.com/mailman/listinfo/wireguard --===============4880338645647588556==--