From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sat, 17 Mar 2007 23:59:05 +1100 From: David Gibson To: Geoff Levand Subject: Re: [PATCH 6/15] zImage: Add more flexible gunzip convenience functions Message-ID: <20070317125905.GA5268@localhost.localdomain> References: <20070305032452.4DCDBDDF1B@ozlabs.org> <45FAC4A2.4060207@am.sony.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <45FAC4A2.4060207@am.sony.com> Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Mar 16, 2007 at 09:24:02AM -0700, Geoff Levand wrote: > David Gibson wrote: > > This patch adds a new set of more flexible convenience wrappers around > > zlib, moving them to their own file, gunzip_util.c, in the process. > > These wrappers allow decompressing sections of the compressed image to > > different locations. In addition, they transparently handle > > uncompressed data, avoiding special case code to handle uncompressed > > vmlinux images. > > Hi. > > I was waiting for the zimage churn to settle before looking into this > change, but I though I would let you know so you can keep it in mind > if you do any work here. > > As I mentioned in another mail, the PS3's 1st stage loader (in the > hypervisor) supports loading a gzipped binary memory image from flash. > So for Linux, that would be a gzipped zImage. Since the entire zImage > is uncompressed by the loader, there is no need to have the kernel image > compressed on its own, nor to include the zlib code in the wrapper. > > Here is a functional expression of what we have now, and what would > be ideal: > > zImage.gz = gzip(wrapper bits + zlib + gzip(vmlinx) + dtb) > > zImage.gz = gzip(wrapper bits + vmlinx + dtb) Ok. The only bit of that we don't do already is omitting zlib from an zImage with a decompressed kernel. I imagine that's a fairly marginal gain, and slightly fiddly to achieve, but we can probably arrange it if we want. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson