On 01/22/2018 02:59 PM, Alexander Graf wrote:
On 01/20/2018 01:56 PM, Heinrich Schuchardt wrote:
The bootefi command has two parameters: the address of the executable and
the address of the flattened device tree.
When executing the devicetree command in grub this command can only
replace an existing device tree. So we always want to pass a device tree.
With the patch the device tree defaults to the internal one. But of cause
the user still can supply his one via the second parameter.
One use case is booting via iPXE from an iSCSI drive. As we may be able
to choose between different operating systems in the iPXE menu we cannot
know the correct device tree when invoking bootefi. The dtb might not
even
be installed on a local device.
Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de>
All of this logic is already implemented in the distro boot script, so
if you load your iPXE EFI binary via dhcp boot, from a block device or
something similar, it will by default already get $fdtcontroladdr passed
in. I'm not sure I'm terribly happy to have additional magic in the
bootefi command. If you want to spawn an EFI binary without device tree
table, you should be able to do so IMHO.
Booting via DHCP is most insecure. Neither the client nor the server are
authenticated.
My understanding is that ftd address is not set by:
load mmc 0:1 0x13000000 snp.efi
bootefi 0x13000000
Where would an fdtadress be determined without loading a dtb?
But giving it a further thought I have to better analyze why Grub fails
to correctly execute 'devicetable' if no fdt has been passed to bootefi.
Let's keep back the patch until the problem is properly understood.
Regards
Heinrich
How do you invoke iPXE?
Alex
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