Extlinux Bootmeth

Extlinux (sometimes called syslinux) allows U-Boot to provide a menu of available operating systems from which the user can choose.

U-Boot includes a parser for the extlinux.conf file. It consists primarily of a list of named operating systems along with the kernel, initial ramdisk and other settings. The file is stored in the extlinux/ subdirectory, possibly under the boot/ subdirectory. This list of prefixes ({"/", "/boot"} by default) can be selected with the filename-prefixes property in the bootstd device.

Note that the PXE Bootmeth uses the same file format, but in a network context.

When invoked on a bootdev, this bootmeth searches for the file and creates a bootflow if found.

When the bootflow is booted, the bootmeth calls pxe_setup_ctx() to set up the context, then pxe_process() to process the file. Depending on the contents, this may boot an operating system or provide a list of options to the user, perhaps with a timeout.

The compatible string “u-boot,extlinux” is used for the driver. It is present if CONFIG_BOOTMETH_EXTLINUX is enabled.