Message-ID: <4702E925.70200@goop.org>
Date: Tue, 02 Oct 2007 17:58:13 -0700
From: Jeremy Fitzhardinge <jeremy@goop.org>
User-Agent: Thunderbird 2.0.0.5 (X11/20070727)
MIME-Version: 1.0
To: "H. Peter Anvin" <hpa@zytor.com>
CC: Rusty Russell <rusty@rustcorp.com.au>,
       lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Vivek Goyal <vgoyal@in.ibm.com>, lguest <lguest@ozlabs.org>,
       "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH 0/5] Boot protocol changes
References: <1191368052.17826.40.camel@localhost.localdomain> <4702D867.2060100@goop.org> <4702D9E2.6020407@zytor.com> <4702DAB5.6090003@goop.org> <4702E5C0.5040606@zytor.com>
In-Reply-To: <4702E5C0.5040606@zytor.com>
Content-Type: text/plain; charset=ISO-8859-15
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1511
Lines: 34

H. Peter Anvin wrote:
> I'm proposing that the existing bzImage format be retained, but that
> the payload of the decompressor (already a gzip file) simply be
> vmlinux.gz -- i.e. a gzip compressed ELF file, notes and all.  A
> pointer in the header will point to the offset of the payload (this is
> new, obviously.)
>
> The decompression stub is adjusted to expect an ELF image, instead of
> a raw binary.

It could, or just treat it as a raw binary at 1M+offset to skip the headers.

> Existing bootloaders (16- or 32-bit) simply load the bzImage the way
> they do now; new bootloaders have the option of accessing the
> vmlinux.gz directly if they either want to load it themselves or want
> to examine the notes. 

OK, but that has the same problem as making the payload an ELF file:
32-bit bootloaders which simply jump to 1M will be jumping into data
rather than code - and I got the impression from taking to Eric at KS
that there are such bootloaders.  

If that's not an issue, then I still think the payload should be a plain
ELF file (possibly self-decompressing, or just a plain uncompressed
vmlinux, if that's what's desired).  Still think making a protected-mode
bootloader do the decompression is the wrong way to go about this; ELF
is enough.

    J
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/