Re: [PATCH v3 11/12] x86, boot: add fields to support load bzImageand ramdisk high

From: H. Peter Anvin
Date: Sat Nov 24 2012 - 13:34:25 EST


On 11/24/2012 10:12 AM, Yinghai Lu wrote:

Now I have a fix ready, also found fix for kexec real mode path working
with recently kernel by settin heap end ptr correctly.

Please decide if we need to add 64 bit entry offset in setup header,
Or just stick to 0x200.

I check grub2 and gujin and qemu , looks like they are all using bzimage
16 bit entry.

Do you have pointer for any boot loader that is using 64 bit entry in
bzimage?


I'm fairly certain Grub2 does *not* use the 16-bit entry point by default even on BIOS platforms, needing the "linux16" directive to behave sanely (this is one of many complete facepalsm in Grub2).

efilinux or elilo compiled for a 64-bit EFI platform would be a good example, bit even if we can't find a 64-bit boot loader example I don't think we can rule one out, so let's just define 0x200 as an ABI constant and be done with it. The cost is minimal and the consequences of changing it are potentially severe.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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