From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1YlUUj-0006DX-Hg for mharc-grub-devel@gnu.org; Thu, 23 Apr 2015 23:41:37 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49173) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YlUUh-00069w-6x for grub-devel@gnu.org; Thu, 23 Apr 2015 23:41:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YlUUd-0006qM-VG for grub-devel@gnu.org; Thu, 23 Apr 2015 23:41:35 -0400 Received: from mail-la0-x229.google.com ([2a00:1450:4010:c03::229]:32823) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YlUUd-0006qG-NM for grub-devel@gnu.org; Thu, 23 Apr 2015 23:41:31 -0400 Received: by layy10 with SMTP id y10so26409173lay.0 for ; Thu, 23 Apr 2015 20:41:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-type:content-transfer-encoding; bh=oa1h964ytlkWne6uXvdMf7PAYcZsOORi1bwB/60FuNo=; b=HBioiTHRSxhqXmqXuk5e+mA1ZMCypgBBZYYDl0oGmh6/RCzzDBKFrUF6AMwCQ06oqr lCkaXA4LFWzu0XTPTkdi1Jw1WOaG7WbmXKtg0gWvOU1buZu7UELrom5Qeab7r5fz5KS3 JEgrJSSctqP19wu2gE16Z/tiOg5cCqpPEfI5BKVDlQs4irOmK5faB89hFs6U1dO9FEEt zvW5wnT4ZIKHsqT2W7eV1oYwGxhrxTXU/j8LtUhfUubmyb+TJtUBFcnJjXrAPniU4gtR Ti16gFgAVXn3OPUbNsxqeulB/0XZOsXqOR2Fpg6tG9WqCQRzJK8aZU4MOV7idn4ykkui GekA== X-Received: by 10.152.27.35 with SMTP id q3mr5116710lag.24.1429846890871; Thu, 23 Apr 2015 20:41:30 -0700 (PDT) Received: from opensuse.site (ppp91-76-14-38.pppoe.mtu-net.ru. [91.76.14.38]) by mx.google.com with ESMTPSA id 4sm36529lai.36.2015.04.23.20.41.29 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Apr 2015 20:41:29 -0700 (PDT) Date: Fri, 24 Apr 2015 06:41:28 +0300 From: Andrei Borzenkov To: "H. Peter Anvin" Subject: Re: [syslinux] Using memdisk with grub2 and a gzip-compressed ISO Message-ID: <20150424064128.71489695@opensuse.site> In-Reply-To: <5539B8C1.4030401@zytor.com> References: <55396F5E.7090303@zytor.com> <20150424061443.3d80329c@opensuse.site> <5539B8C1.4030401@zytor.com> X-Mailer: Claws Mail 3.11.0 (GTK+ 2.24.27; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2a00:1450:4010:c03::229 Cc: grub-devel@gnu.org, David Shaw , syslinux@zytor.com X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Apr 2015 03:41:36 -0000 =D0=92 Thu, 23 Apr 2015 20:30:09 -0700 "H. Peter Anvin" =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > On 04/23/2015 08:14 PM, Andrei Borzenkov wrote: > > =D0=92 Thu, 23 Apr 2015 15:17:02 -0700 > > "H. Peter Anvin" =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > >=20 > >> On 04/23/2015 07:23 AM, David Shaw via Syslinux wrote: > >>> > >>> I'm not sure if this is related to the problem, but note the length > >>> in the "Ramdisk" line from grub legacy is one byte shorter than the > >>> length from grub2. Also note that the length given in the "gzip > >>> image" line is shifted one byte to the left in the grub legacy > >>> version (i.e. it's exactly 0x100 times larger). > >>> > >> > >> That would definitely break using a compressed ramdisk. > >=20 > > It does not break for kernel. What makes is so different in case of > > syslinux? > >=20 >=20 > Padding the image doesn't matter for the kernel, but memdisk relies on > being able to see where the end of the compressed image is, because that > is where the length is located. CRC+length (in case of gzip) are located immediately after compressed stream. After stream is decompressed you get location where it ends and automatically where length is located.