From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755346AbYLOL1h (ORCPT ); Mon, 15 Dec 2008 06:27:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753210AbYLOL12 (ORCPT ); Mon, 15 Dec 2008 06:27:28 -0500 Received: from mail.gmx.net ([213.165.64.20]:36763 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753116AbYLOL12 (ORCPT ); Mon, 15 Dec 2008 06:27:28 -0500 X-Authenticated: #34473864 X-Provags-ID: V01U2FsdGVkX18x9Rd5YBMxXVqUoUREsDsDM2MFm4roc2viUL24yf 7XsjzSUmq9RIjV Message-ID: <49463F1C.1070401@gmx.de> Date: Mon, 15 Dec 2008 12:27:24 +0100 From: Philipp Kohlbecher User-Agent: Thunderbird 2.0.0.18 (X11/20081125) MIME-Version: 1.0 To: Ian Campbell CC: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: documentation fix regarding boot protocol References: <49454749.2030901@gmx.de> <1229332954.25349.78.camel@zakaz.uk.xensource.com> In-Reply-To: <1229332954.25349.78.camel@zakaz.uk.xensource.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 X-FuHaFi: 0.52 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ian Campbell wrote: > On Sun, 2008-12-14 at 18:50 +0100, Philipp Kohlbecher wrote: >> Documentation/x86/boot.txt describes payload_offset as the offset >> from the end of the real-mode code. In fact, it is more accurately >> described as the offset from the beginning of the protected-mode >> code, as (a) this is how it is actually calculated and (b) the padding >> after the real-mode code is not included in the offset. >> >> Signed-off-by: Philipp Kohlbecher > > Acked-by: Ian Campbell > > The padding after the real-mode code which you mention is just the > implicit padding because the size of the real-mode code is specified in > sectors (and hence is rounded up), isn't it? Yes, it is. You can certainly view the padding as an implicit part of the real-mode code, which is why the current statement isn't wrong -- there is simply room for improvement. > Is it worth saying that the payload_offset is relative to (setup_sectors > +1) * 512? The fact that the protected-mode code starts at that address is already mentioned under the heading "LOADING THE REST OF THE KERNEL" (where protected mode is for some reason referred to as "non-real-mode"). (Please note that the header field is called "setup_sects", not "setup_sectors".) >> --- >> >> Documentation/x86/boot.txt | 4 ++-- >> 1 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt >> index 83c0033..414b6fb 100644 >> --- a/Documentation/x86/boot.txt >> +++ b/Documentation/x86/boot.txt >> @@ -537,8 +537,8 @@ Type: read >> Offset/size: 0x248/4 >> Protocol: 2.08+ >> >> - If non-zero then this field contains the offset from the end of the >> - real-mode code to the payload. >> + If non-zero then this field contains the offset from the beginning >> + of the protected-mode code to the payload. >> >> The payload may be compressed. The format of both the compressed and >> uncompressed data should be determined using the standard magic >>