From owner-svn-src-projects@freebsd.org Tue Sep 22 18:37:46 2015 Return-Path: Delivered-To: svn-src-projects@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C5FF1A066A0 for ; Tue, 22 Sep 2015 18:37:46 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from mail-pa0-f44.google.com (mail-pa0-f44.google.com [209.85.220.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 9C0271D60 for ; Tue, 22 Sep 2015 18:37:46 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: by pacex6 with SMTP id ex6so16386935pac.0 for ; Tue, 22 Sep 2015 11:37:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:subject:mime-version:content-type:from :in-reply-to:date:cc:message-id:references:to; bh=Mrbwp6S8S8INJFe6lQICV5MzgT1LYjFQQdSLiQ5ndho=; b=OhjxWfhpUp7ZwpZj9m4pmoI15ZsSr8YpFHDtA8HqYi06R8gegBpUeP+XEianb52jU/ ZA8uzgs1W8xQVk46e/Y/R7uHpKNIMcpS7lXDRKxYh0g30oHljmbVyc3kkIuW/5wPQpVJ V5RRmXtsrB7fO2HVkLNFrAheOGXb7OIX9kOeAPnqm8rgCYQyxVWMN/puv7KWEoHZoiU2 3+uyxxRPoTSgGFZUWmwMljuF1Kwq76SlTiwSGw4nYTmKSKVfPcokC6+7atrQCFcPMDSO ATn6jewH7fdffIkkcV3gED6V4rDLThtXD0Vaa/bcnyGkC1TFjM1efEhTMmuqKqbPcGeq rulw== X-Gm-Message-State: ALoCoQnbdHRhl5ATl3KaTaREDz27CYZlRf0xx+Xyo7m3btSaPaqu7nEZHaKAePhd0509fuEW0OdQ X-Received: by 10.68.95.3 with SMTP id dg3mr33162686pbb.35.1442947065512; Tue, 22 Sep 2015 11:37:45 -0700 (PDT) Received: from [192.168.1.118] ([40.140.178.138]) by smtp.gmail.com with ESMTPSA id tk4sm3568755pab.45.2015.09.22.11.37.44 (version=TLS1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 22 Sep 2015 11:37:44 -0700 (PDT) Sender: Warner Losh Subject: Re: svn commit: r288121 - projects/clang370-import/contrib/libc++/src/support Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) Content-Type: multipart/signed; boundary="Apple-Mail=_3ABD3349-B2E3-490F-8351-6D07CD7E1C5C"; protocol="application/pgp-signature"; micalg=pgp-sha512 X-Pgp-Agent: GPGMail 2.5 From: Warner Losh In-Reply-To: <201509221734.t8MHYp0W052286@repo.freebsd.org> Date: Tue, 22 Sep 2015 12:37:42 -0600 Cc: src-committers@freebsd.org, svn-src-projects@freebsd.org Message-Id: <00F42FF7-84D4-4C97-974F-C28DB36D4392@bsdimp.com> References: <201509221734.t8MHYp0W052286@repo.freebsd.org> To: Dimitry Andric X-Mailer: Apple Mail (2.2104) X-BeenThere: svn-src-projects@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "SVN commit messages for the src " projects" tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Sep 2015 18:37:47 -0000 --Apple-Mail=_3ABD3349-B2E3-490F-8351-6D07CD7E1C5C Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Sep 22, 2015, at 11:34 AM, Dimitry Andric wrote: > NOTE: this needs to be fixed properly later on, by supplying library > functions implementing atomic operations for arm < v6. We should > probably take those from sys/arm/arm/stdatomic.c, and stuff them into > either libgcc or compiler-rt. I don=E2=80=99t think you can do that. arm < v6 is special. The CPUs don=E2=80=99t have atomic operations. In = the kernel, we disable interrupts and do the op. You can=E2=80=99t do that in user = land. Instead, you have to use RAS (Restartable Atomic Sequences) and have the kernel grok the RAS. Thankfully, the RAS support in the kernel is just the R in = that. But it does mean that we=E2=80=99ll have some work to do this properly. I=E2=80=99m not entirely sure that your =E2=80=98fix=E2=80=99 makes = things actually safe, even if it seems to make them work today. I=E2=80=99ll have to study it more = closely. Warner --Apple-Mail=_3ABD3349-B2E3-490F-8351-6D07CD7E1C5C Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJWAZ/2AAoJEGwc0Sh9sBEA6CEP/R/uNIrW2u2WD4Us7G0zTR8d v6xpXVIgnz574slfWVB50LV3eQsD5aCgDQQ9SdgWntrb2t87LJXvPnCs2Sm4kNBO s4JNN6ZFc1YdWDKldUAa/b5zGi9mtkUQPpjl5ODzXLZ2ovuQS1TABHYD2mDV5ZL6 CbdgVsCgWCmjsuqUAYWrJDAM1a7CLxR1hXCZwMqO4Usocc2NDFB7fJpBA/YGTUZI z5TkmLsIZ7f2yHPOoMC3JPIpk7o2CbvZP/mNIWMIBDR3a2pks1CNkua6AKBYspxy tYZHzq9nBnfmR4vzPMeZ4m0JOoYj92GjYf6NlvAEupNaETgeAKvzbeb3ysaVhTPd iCeDdrp0W2JW1oDiKtDq8S3Miaw4DibvbP74/H3ijkM8RmPHcy0FH0H0fJ95gDGQ pqNytiAwpuUtXK7ZXa+GrJEQ6SnoTMtbgZO35SOFNnBY7xDrlzeOIqgSbEICxwi5 X7opBIc28I+NxW6Ei2a92+3XA/VwyPQExNTdk/lh/3YL08zJXaHSTdiNzr4qbZKp V9+tz9FDk6ov2cyNBMTYq6XyXIum22PZFhakFhGMIIZGdr5PTWn+NslgibRM/QyG LW4sKHxc+rDe+/EZeA6AWHW+EIw2BykYly2brRM+om2lIPuPGwAHR+RuSx7sYtiC 5sytL3pB6bgdI0jbA+Vw =Tk8n -----END PGP SIGNATURE----- --Apple-Mail=_3ABD3349-B2E3-490F-8351-6D07CD7E1C5C--