From owner-svn-src-head@freebsd.org Thu Jan 11 12:07:26 2018 Return-Path: Delivered-To: svn-src-head@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 01A24EA53C9; Thu, 11 Jan 2018 12:07:26 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id CF5D56C8E7; Thu, 11 Jan 2018 12:07:25 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 0CE7F149CC; Thu, 11 Jan 2018 12:07:25 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w0BC7O2v094921; Thu, 11 Jan 2018 12:07:24 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w0BC7O9p094919; Thu, 11 Jan 2018 12:07:24 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201801111207.w0BC7O9p094919@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Thu, 11 Jan 2018 12:07:24 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r327816 - in head/sys: amd64/amd64 i386/i386 X-SVN-Group: head X-SVN-Commit-Author: kib X-SVN-Commit-Paths: in head/sys: amd64/amd64 i386/i386 X-SVN-Commit-Revision: 327816 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 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: Thu, 11 Jan 2018 12:07:26 -0000 Author: kib Date: Thu Jan 11 12:07:24 2018 New Revision: 327816 URL: https://svnweb.freebsd.org/changeset/base/327816 Log: Update comment explaining the check, to reality. Discussed with: jhb Sponsored by: The FreeBSD Foundation MFC after: 3 days Modified: head/sys/amd64/amd64/support.S head/sys/i386/i386/support.s Modified: head/sys/amd64/amd64/support.S ============================================================================== --- head/sys/amd64/amd64/support.S Thu Jan 11 09:42:24 2018 (r327815) +++ head/sys/amd64/amd64/support.S Thu Jan 11 12:07:24 2018 (r327816) @@ -249,12 +249,10 @@ ENTRY(copyout) jz done_copyout /* - * Check explicitly for non-user addresses. If 486 write protection - * is being used, this check is essential because we are in kernel - * mode so the h/w does not provide any protection against writing - * kernel addresses. + * Check explicitly for non-user addresses. This check is essential + * because it prevents usermode from writing into kernel. We do not + * verify that user did not specified a rogue address anywhere else. */ - /* * First, prevent address wrapping. */ Modified: head/sys/i386/i386/support.s ============================================================================== --- head/sys/i386/i386/support.s Thu Jan 11 09:42:24 2018 (r327815) +++ head/sys/i386/i386/support.s Thu Jan 11 12:07:24 2018 (r327816) @@ -291,12 +291,10 @@ ENTRY(copyout) jz done_copyout /* - * Check explicitly for non-user addresses. If 486 write protection - * is being used, this check is essential because we are in kernel - * mode so the h/w does not provide any protection against writing - * kernel addresses. + * Check explicitly for non-user addresses. This check is essential + * because it prevents usermode from writing into kernel. We do not + * verify that user did not specified a rogue address anywhere else. */ - /* * First, prevent address wrapping. */