[syslinux] [PATCH] efi: leaving long mode in kernel_jump routine
Patrick Masotta
masottaus at yahoo.com
Sat Aug 8 10:04:56 PDT 2015
>>>
> Syslinux 6.03 (efi64) fails to boot a 32-bit kernel. The way Syslinux
> leaves long mode in kernel_jump assembly routine does not follow AMD64
> specifications. More precisely:
> 1. After setting a new GADT, `cs` has to be refresh by doing a long
> jump, but it is not
> 2. Other segments have to be updated, but they are not
> 3. Disabling paging has to be done before disabling long mode, but the
> implementation does the opposite
>
> In most cases, computer that tries to execute the kernel_jump routine
> reboot (it can also hangs). This patch fixes the kernel_jump routine.
>
Is this patch going to be yet another one that will be "lost" in the mailing list?
Is this patch incorrect? Not useful? Unnecessary?
<<<
It seems "it is" necessary, I'll be probably testing it next week.
>>>
Newer kernels are supposed to respect certain rules / standards /
protocols, and IF everything is done "adequately", then Syslinux (BIOS
/ EFI*) should be able to boot such newish kernels.
<<<
AFAIK it seems this patch is even necessary for new kernels in the case
EFI64 boots a 32 Bit kernel, right?
Best,
Patrick
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