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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/develop/uefi/uefi.rst | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/doc/develop/uefi/uefi.rst b/doc/develop/uefi/uefi.rst index b3494c22e0..d92a32016e 100644 --- a/doc/develop/uefi/uefi.rst +++ b/doc/develop/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 +490,21 @@ 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 ----- |