brain-hackers_pepepper-mirror/u-boot-brain
1
0
Fork 0
mirror of https://github.com/brain-hackers/u-boot-brain synced 2024-06-09 23:36:03 +09:00
Code Issues Projects Releases Wiki Activity

doc: Update uefi documentation for initrd loading options

Browse Source 
Document the command line options for efidebug and initrd loading

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Rewiewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Ilias Apalodimas 2021-03-17 21:55:02 +02:00 committed by Heinrich Schuchardt
parent a1e95e3805
commit cd64031c16
1 changed files with 21 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
doc/develop/uefi/uefi.rst
View File

@ -180,6 +180,12 @@ Set up boot parameters on your board::
efidebug boot add -b 1 HELLO mmc 0:1 /helloworld.efi.signed ""
Since kernel 5.7 there's an alternative way of loading an initrd using
LoadFile2 protocol if CONFIG_EFI_LOAD_FILE2_INITRD is enabled.
The initrd path can be specified with::
efidebug boot add -b ABE0 'kernel' mmc 0:1 Image -i mmc 0:1 initrd
Now your board can run the signed image via the boot manager (see below).
You can also try this sequence by running Pytest, test_efi_secboot,
on the sandbox
@ -484,7 +490,21 @@ The load file 2 protocol can be used by the Linux kernel to load the initial
RAM disk. U-Boot can be configured to provide an implementation with::
EFI_LOAD_FILE2_INITRD=y
EFI_INITRD_FILESPEC=interface dev:part path_to_initrd
When the option is enabled the user can add the initrd path with the efidebug
command.
Load options Boot#### have a FilePathList[] member. The first element of
the array (FilePathList[0]) is the EFI binary to execute. When an initrd
is specified the Device Path for the initrd is denoted by a VenMedia node
with the EFI_INITRD_MEDIA_GUID. Each entry of the array is terminated by the
'end of entire device path' subtype (0xff). If a user wants to define multiple
initrds, those must by separated by the 'end of this instance' identifier of
the end node (0x01).
So our final format of the FilePathList[] is::
Loaded image - end node (0xff) - VenMedia - initrd_1 - [end node (0x01) - initrd_n ...] - end node (0xff)
Links
-----