man.postnix Miscellaneous man pages of Plan 9 related material

     BOOT(3)                                                   BOOT(3)

     NAME
          boot - reboot under program control

     SYNOPSIS
          bind -a #B /dev

          /dev/boot
          /dev/kexec
          /dev/mem

     DESCRIPTION
          Boot serves a directory containing three files that control
          a reboot of the system.  The files can only be opened by the
          host owner (see eve(10.2)).

          Boot is a write-only file that accepts 4 bytes representing
          a kernel address, high-order byte first.  The system will
          transfer control to that address, which is assumed to be the
          start of low-level reboot code.  There is no return from the
          write on success or failure.

          Kexec is a write-only file to which an uncompressed kernel
          image can be written, a chunk at a time.  When the file is
          closed, the system will transfer control to the start of the
          image, which again is assumed to be low-level reboot code.

          Mem copies data to and from kernel memory, taking the cur-
          rent file offset as an address therein.

          Boot flushes caches as necessary to ensure that writes to
          kernel memory through any of these files will be visible
          when subsequently executed as instructions.

     SOURCE
          /os/port/devboot.c

     SEE ALSO
          tftp(2), cons(3)

     DIAGNOSTICS
          Invalid addresses are diagnosed, but otherwise there is no
          error return.

     Page 1                       Plan 9            (printed 12/22/24)