Syslinux - Jul 2013 - Syslinux-6.02-pre2 - booting 32-bit kernels from efi64

I just released 6.02-pre2 which includes support for booting 32-bit
kernels from efi64. I know a number of people wanted this feature, so
hopefully it will be tested in various environments.

One thing to note is that it is not possible to boot a 32-bit kernel
from efi64 via the EFI handover protocol (or from firmware via the EFI
boot stub), but the kernel loader in Syslinux is smart enough to
fallback to the legacy scheme and just not use any of the EFI boot stub
code when mixing firmware/kernels.

-- 
Matt Fleming, Intel Open Source Technology Center

Am 08.07.2013 18:32, schrieb Matt Fleming:
> I just released 6.02-pre2 which includes support for booting 32-bit
> kernels from efi64. I know a number of people wanted this feature, so
> hopefully it will be tested in various environments.
>
> One thing to note is that it is not possible to boot a 32-bit kernel
> from efi64 via the EFI handover protocol (or from firmware via the EFI
> boot stub), but the kernel loader in Syslinux is smart enough to
> fallback to the legacy scheme and just not use any of the EFI boot stub
> code when mixing firmware/kernels.
>
During my tests, it did not work. When selecting a 32bit kernel entry, 
screen went black for about 2 seconds, then dropped back to Syslinux 
menu. 64bit kernel booted just fine.

Any further info I can give you to debug this? Are there any specific 
requirements for the kernel?

Thanks,
Andreas

On Wed, 10 Jul, at 03:44:57PM, Andreas Heinlein wrote:
> Am 08.07.2013 18:32, schrieb Matt Fleming:
> >I just released 6.02-pre2 which includes support for booting 32-bit
> >kernels from efi64. I know a number of people wanted this feature, so
> >hopefully it will be tested in various environments.
> >
> >One thing to note is that it is not possible to boot a 32-bit kernel
> >from efi64 via the EFI handover protocol (or from firmware via the EFI
> >boot stub), but the kernel loader in Syslinux is smart enough to
> >fallback to the legacy scheme and just not use any of the EFI boot stub
> >code when mixing firmware/kernels.
> >
> During my tests, it did not work. When selecting a 32bit kernel
> entry, screen went black for about 2 seconds, then dropped back to
> Syslinux menu. 64bit kernel booted just fine.
> 
> Any further info I can give you to debug this? Are there any
> specific requirements for the kernel?
 
You could try running,

debug.c32 -e efi_boot_linux handover_boot

before executing your kernel. What kernel version are you using?

-- 
Matt Fleming, Intel Open Source Technology Center

On Wed, 10 Jul, at 03:44:57PM, Andreas Heinlein wrote:
> Am 08.07.2013 18:32, schrieb Matt Fleming:
> >I just released 6.02-pre2 which includes support for booting 32-bit
> >kernels from efi64. I know a number of people wanted this feature, so
> >hopefully it will be tested in various environments.
> >
> >One thing to note is that it is not possible to boot a 32-bit kernel
> >from efi64 via the EFI handover protocol (or from firmware via the EFI
> >boot stub), but the kernel loader in Syslinux is smart enough to
> >fallback to the legacy scheme and just not use any of the EFI boot stub
> >code when mixing firmware/kernels.
> >
> During my tests, it did not work. When selecting a 32bit kernel
> entry, screen went black for about 2 seconds, then dropped back to
> Syslinux menu. 64bit kernel booted just fine.
What kernel were you booting?

That sounds very much like the kernel returned control to Syslinux,
which is kinda weird.

-- 
Matt Fleming, Intel Open Source Technology Center