OCTBOOT(4) Device Drivers Manual (octeon) OCTBOOT(4)

octboot — kernel boot interface

pseudo-device octboot

The octboot driver provides an ioctl(2) interface for booting into another kernel from the currently running kernel.

octboot provides the following ioctl(2) commands, available through <machine/octboot.h>:

char rootdev[PATH_MAX]
Get the name of the current root device.
Boot into the given kernel image. 
struct octboot_kexec_args {
	char		*kimg;
	size_t		 klen;
	char		*argv[OCTBOOT_MAX_ARGS];
};

/dev/octboot
boot interface device.

ioctl(2), intro(4)

The octboot driver first appeared in OpenBSD 6.6.

OpenBSD 7.8 October 10, 2020 OCTBOOT(4)