From owner-freebsd-stable Mon Feb 24 13:50:58 2003 Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CD61937B401 for ; Mon, 24 Feb 2003 13:50:56 -0800 (PST) Received: from wrzx35.rz.uni-wuerzburg.de (wrzx35.rz.uni-wuerzburg.de [132.187.3.35]) by mx1.FreeBSD.org (Postfix) with ESMTP id D281743FA3 for ; Mon, 24 Feb 2003 13:50:52 -0800 (PST) (envelope-from q@uni.de) Received: from wrzx34.rz.uni-wuerzburg.de (wrzx34.rz.uni-wuerzburg.de [132.187.3.34]) by wrzx35.rz.uni-wuerzburg.de (8.8.8/8.8.8/uniwue-MM-1.05) with ESMTP id WAA293160; Mon, 24 Feb 2003 22:50:47 +0100 (CET) Received: from virusscan (localhost [127.0.0.1]) by wrzx34.rz.uni-wuerzburg.de (Postfix) with ESMTP id E7122678F4; Mon, 24 Feb 2003 22:50:46 +0100 (CET) Received: from wrzx07.rz.uni-wuerzburg.de ([132.187.1.7]) by virusscan (wrzx34 [132.187.3.34:25]) (amavisd-new) with ESMTP id 25019-04; Mon, 24 Feb 2003 22:50:46 +0100 (CET) Received: from spamchecker (localhost [127.0.0.1]) by wrzx07.rz.uni-wuerzburg.de (Postfix) with ESMTP id CBD2A471C; Mon, 24 Feb 2003 22:50:45 +0100 (CET) Received: from coyote.dnsalias.net (gb-007.galgenberg.net [132.187.222.7]) by wrzx07.rz.uni-wuerzburg.de (Postfix) with ESMTP id 8FF8046F4; Mon, 24 Feb 2003 22:50:45 +0100 (CET) Received: from roadrunner.local (roadrunner [192.168.0.147]) by coyote.dnsalias.net (8.12.6/8.12.6) with ESMTP id h1OLojjM012126; Mon, 24 Feb 2003 22:50:45 +0100 (CET) (envelope-from q@uni.de) Received: from roadrunner.local (localhost [127.0.0.1]) by roadrunner.local (8.12.6/8.12.6) with ESMTP id h1OLohWV041207; Mon, 24 Feb 2003 22:50:43 +0100 (CET) (envelope-from q@uni.de) Received: (from q@localhost) by roadrunner.local (8.12.6/8.12.6/Submit) id h1OLogSe041201; Mon, 24 Feb 2003 22:50:42 +0100 (CET) X-Authentication-Warning: roadrunner.local: q set sender to q@uni.de using -f Date: Mon, 24 Feb 2003 22:50:41 +0100 From: Ulrich Spoerlein To: Luoqi Chen Cc: freebsd-stable@FreeBSD.ORG Subject: Re: How to debug mmap(2) with pcm(3)? Message-ID: <20030224215041.GA289@galgenberg.net> Mail-Followup-To: Luoqi Chen , freebsd-stable@FreeBSD.ORG References: <20030224210726.GC87555@galgenberg.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="AhhlLboLdkugWU4S" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4i X-No-Archive: yes X-Spam-Status: No, hits=-13.8 required=8.0 tests=IN_REP_TO,LOCAL_CLIENT,NICE_HELO,PGP_SIGNATURE_2, QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_00_01,USER_AGENT, USER_AGENT_MUTT,WEIRD_SUBJ,X_AUTH_WARNING version=2.43-string_20021002 X-Spam-Level: X-Virus-Scanned: by amavisd-new (Rechenzentrum Universitaet Wuerzburg) Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG --AhhlLboLdkugWU4S Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, 24.02.2003 at 13:30:30 -0800, Luoqi Chen wrote: > This is a "feature" of ia32 architecture, there isn't a notion of > write-only memory access, write access implies read access. If you > want to "fix" the problem with pcm device, very simple, go to file > sys/i386/trap.c and replace all occurrences of PROT_READ|PROT_WRITE > with PROT_WRITE. Hmm, I only have a few occurrences of VM_PROT_READ/_WRITE in that file. Well, why is the piece of OSS Code working on -CURRENT? And why does the man-page say nothing about implicit read-access when trying to write? Why does the mmap() not fail, but _always_ return a pointer with value 0x28104000? Couln't someone with more knowledge look into this issue? --AhhlLboLdkugWU4S Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (FreeBSD) iD8DBQE+WpOxmArGtfDbn0QRAhUKAKDbyXs/I64M7XF4FGGsVQL7J4v+NwCgurDc iPvzQZxPoGpyQq1CoYseZn4= =rKva -----END PGP SIGNATURE----- --AhhlLboLdkugWU4S-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message