Document the command line options for efidebug and initrd loading
Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org --- doc/uefi/uefi.rst | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/doc/uefi/uefi.rst b/doc/uefi/uefi.rst index b3494c22e073..76402bc5cfaa 100644 --- a/doc/uefi/uefi.rst +++ b/doc/uefi/uefi.rst @@ -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 +490,20 @@ 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 options is enabled the user can add the initrd path with the efidebug +command. +The Boot#### option has a FilePathList[] in it's EFI_LOAD_OPTION. +The first element of the array (FilePathList[0]) is the loded image. +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. If the 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 - initrd1 - end node (0x01) initrd2 - end node (0xff)
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