From owner-svn-src-head@FreeBSD.ORG Mon May 28 13:36:59 2012 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id D9D00106566B; Mon, 28 May 2012 13:36:59 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id 4FFE08FC0A; Mon, 28 May 2012 13:36:59 +0000 (UTC) Received: from skuns.kiev.zoral.com.ua (localhost [127.0.0.1]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id q4SDaYDF060694; Mon, 28 May 2012 16:36:34 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.5/8.14.5) with ESMTP id q4SDaXIT012101; Mon, 28 May 2012 16:36:33 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.5/8.14.5/Submit) id q4SDaX6J012100; Mon, 28 May 2012 16:36:33 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Mon, 28 May 2012 16:36:33 +0300 From: Konstantin Belousov To: Bruce Evans Message-ID: <20120528133633.GB2358@deviant.kiev.zoral.com.ua> References: <201205252150.q4PLomFk035064@svn.freebsd.org> <20120526173233.A885@besplex.bde.org> <20120526164927.GU2358@deviant.kiev.zoral.com.ua> <20120527043827.W3357@besplex.bde.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="tYqdTR6Mwu/xEI6p" Content-Disposition: inline In-Reply-To: <20120527043827.W3357@besplex.bde.org> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.0 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, Ed Schouten , rwatson@freebsd.org, svn-src-head@freebsd.org, jonathan@freebsd.org Subject: Re: svn commit: r236026 - in head/sys: amd64/linux32 compat/freebsd32 kern X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 28 May 2012 13:37:00 -0000 --tYqdTR6Mwu/xEI6p Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, May 27, 2012 at 07:49:36AM +1000, Bruce Evans wrote: > On Sat, 26 May 2012, Konstantin Belousov wrote: >=20 > >On Sat, May 26, 2012 at 10:21:25PM +1000, Bruce Evans wrote: > >The 'low level' AKA magic happens in several *_fetch_syscall_args() > >functions. For both linux32 and freebsd32, the magic code automatically > >zero-extends the arguments into 64bit entities. Linux passes args in > >registers, while FreeBSD uses words on stack. >=20 > Actually, the amd64 linux_fetch32_fetch_syscall_args() just copies from > 64-bit registers frame->tf_r* to 64-bit sa->args[*]. I can't see how > this gives anything except garbage in the top bits. Is there magic in > the switch to 64-bit mode that sets the top bits? Anyway, sign extension > would give garbage for unsigned args, and zero-extension would give > garbage for negative signed args. Hardware zero-extends any register touched in the 32bit mode. In fact, please see r217991 for related bug. --tYqdTR6Mwu/xEI6p Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (FreeBSD) iEYEARECAAYFAk/Df2EACgkQC3+MBN1Mb4ip6wCgggnSTu1Pu2ez7ezggGkwCKAC r+4An1hr9XYzUqXU6Mg19LKkFUWuareL =UlcY -----END PGP SIGNATURE----- --tYqdTR6Mwu/xEI6p--