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Date: Mon, 31 Jul 2006 17:00:50 -0400
From: Vivek Goyal <vgoyal@in.ibm.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: fastboot@osdl.org, Horms <horms@verge.net.au>,
       Jan Kratochvil <lace@jankratochvil.net>,
       "H. Peter Anvin" <hpa@zytor.com>, Magnus Damm <magnus.damm@gmail.com>,
       linux-kernel@vger.kernel.org
Subject: Re: [Fastboot] [CFT] ELF Relocatable x86 and x86_64 bzImages
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On Mon, Jul 31, 2006 at 04:25:20PM -0400, Vivek Goyal wrote:
> On Mon, Jul 31, 2006 at 10:19:04AM -0600, Eric W. Biederman wrote:
> > 
> > I have spent some time and have gotten my relocatable kernel patches
> > working against the latest kernels.  I intend to push this upstream
> > shortly.
> > 
> > Could all of the people who care take a look and test this out
> > to make certain that it doesn't just work on my test box?
> > 
> Hi Eric,
> 
> Currently I am testing your patches on i386. With CONFIG_RELOCATABLE=y
> kernel boots fine and kexec also works.
> 
> But my kernel hangs on kexec on panic case. It hangs early in 
> decompress_kernel(). Kernel hangs at following condition.
> 
> +       if (((u32)output - CONFIG_PHYSICAL_START) & 0x3fffff)
> +               error("Destination address not 4M aligned");
> 

Ok. I am decompressing the kernel to 16MB and after reducing 1MB of
CONFIG_PHYSICAL_START I am left with 15MB which is not 4M aligned
hence I seems to be running into it.

I changed it to

if ((u32)output) & 0x3fffff)

and kdump kernel booted fine. But this will run into issues if I load
kernel at 1MB.

I got a dump question. Why do I have to load the kernel at 4MB alignment?
Existing kernel boots loads at 1MB, which is non 4MB aligned and it works
fine?

Thanks
Vivek