Re: [Qemu-devel] [PATCH] QEMU: ARM: boot: Load kernel at an Image friendly address

[Christopher Covington <cov@codeaurora.org>]

Hi Joel,

On 03/24/2014 11:34 PM, Joel Fernandes wrote:
> Loading kernel at offset 0x10000 works only for zImage, but not for Image,
> because the kernel expect the start of decompressed kernel (.head.text) to be

Nit: expects

> at an address that's a distance that's 16MB aligned from  PAGE_OFFSET +
> TEXT_OFFSET (see vmlinux.lds.S). This check is enfornced in __fixup_pv_table in

Nit: enforced

> arch/arm/kernel/head.S TEXT_OFFSET is 0x00008000, so a 16MB alignment needs to
> have a "0x8000" in the lower 16 bits so that they cancel out. Currently the
> offset Qemu loads it at is 0x10000.
> 
> With zImage, this need is met because zImage loads the uncompressed Image
> correctly, however when loading an Image and executing directly Qemu is
> required it to load it at the correct location. Doing so, doesn't break Qemu's
> zImage loading. With this patch, both zImage and Image work correctly.

I had just been playing with my own version of this change. Glad to see it
going upstream.

Tested-by: Christopher Covington <cov@codeaurora.org>

Thanks,
Christopher

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.