[RFC] [PATCH] PowerPC: add more than 4MB kernel image size support to bootwarapper
david at gibson.dropbear.id.au
Tue Sep 25 12:29:35 EST 2007
On Mon, Sep 24, 2007 at 03:36:27PM +0400, Valentine Barshak wrote:
> Currently zImage is linked at the 4MB base address.
> Some platforms (using cuboot, treeboot) need the zImage's
> entry point and base address. They place zImage exactly
> at the base address it's been linked to. Sometimes 4MB left
> at the start of the memory is simply not enough to unpack zImage.
> This could happen with initramfs enabled, since the kernel image
> packed along with initramfs.cpio could be over 5MB in size.
> This patch checks vmlinux image size and links zImage at
> the base address that is equal to the unpacked image size
> aligned to 4MB boundary. This way zImage base address is 4MB
> only if unpacked kernel image size is less then 4MB.
Good plan. However..
> diff -ruN linux-2.6.orig/arch/powerpc/boot/zImage.lds.S linux-2.6/arch/powerpc/boot/zImage.lds.S
> --- linux-2.6.orig/arch/powerpc/boot/zImage.lds.S 2007-09-22 00:48:08.000000000 +0400
> +++ linux-2.6/arch/powerpc/boot/zImage.lds.S 2007-09-22 04:03:58.000000000 +0400
> @@ -3,7 +3,7 @@
> - . = (4*1024*1024);
> + . = ALIGN((_kend - _kstart), (4*1024*1024));
..I don't see any reason to keep the 4MB granularity. I would just
align the address to say a 64k boundary (64k because that's the
granularity used in the normal ABI).
> _start = .;
> .text :
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> Linuxppc-dev at ozlabs.org
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
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