Re: [PATCH 1/1] Fix boot on efi 32 bit Machines [try #4]

[Edgar Hucek]

I converted the efi memory map to use the e820 table.
While converting i discovered why the kernel would allways
fail to boot through efi on Intel Macs without a proper fix.

>From kernel 2.6.16 to kernel 2.6.17 a new check is made.
File arch/i386/pci/mmconfig.c -> funktion pci_mmcfg_init -> check e820_all_mapped
The courios thing is that this check will always fail on the
Intel Macs booted through efi. Parsing of the ACPI_MCFG table
returns e0000000 for the start. But this location is
not in the memory map which the efi firmware have :
BIOS-EFI: 00000000e00f8000 - 00000000e00f9000 (reserved)
So the e820_all_mapped would allways fail.
Anny suggestions how to fix this problem ? Maybe some kind
of whitelisting, using dmi_check_system ?

cu

Edgar Hucek


Eric W. Biederman schrieb:
> Edgar Hucek <hostmaster@xxxxxxxxxx> writes:
> 
>> I agre with you to make efi use the e820 map as a long term solution.
>> But at the moment the efi part is completley broken without my patch.
> 
> But your patch isn't a fix.  It is a hack to make the system boot.
> 
> A patch that performed the same check on the efi memory map,
> or it converted the efi memory map to use an e820 map it would be a fix.
> 
>> At least on Intel Macs. 
>> Without the patch also my Imacfb driver makes no sense, since it is 
>> for efi booted Intel Macs. 
> 
> My point is that the kernel efi support is broken.  You have just found
> the location where the bone is poking through the skin.
> 
> I am tempted to write a patch to delete the x86 efi support at this
> point.  So that it is very clear that it needs to be completely redone.
> 
> Eric
> 

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