Provided by: kexec-tools_2.0.2-3ubuntu4_amd64 bug

NAME

       kexec - directly boot into a new kernel

SYNOPSIS

       /sbin/kexec  [-v (--version)] [-f (--force)] [-x (--no-ifdown)] [-l (--load)] [-p (--load-
       panic)] [-u (--unload)] [-e (--exec)] [-t (--type)] [--mem-min=addr] [--mem-max=addr]

DESCRIPTION

       kexec is a system call that enables you to load and boot  into  another  kernel  from  the
       currently  running kernel.  kexec performs the function of the boot loader from within the
       kernel. The primary difference between a standard system boot and a kexec boot is that the
       hardware  initialization  normally  performed  by  the  BIOS  or  firmware  (depending  on
       architecture) is not performed during a kexec boot. This has the effect  of  reducing  the
       time required for a reboot.

       Make  sure  you have selected CONFIG_KEXEC=y when configuring the kernel. The CONFIG_KEXEC
       option enables the kexec system call.

USAGE

       Using kexec consists of

              (1) loading the kernel to be rebooted to into memory, and
              (2) actually rebooting to the pre-loaded kernel.

       To load a kernel, the syntax is as follows:

              kexec -l kernel-image --append=command-line-options --initrd=initrd-image

       where kernel-image is the kernel file that you intend to reboot to.

       Insert  the  command-line  parameters  that  must  be  passed  to  the  new  kernel   into
       command-line-options.     Passing    the    exact    contents    of   /proc/cmdline   into
       command-line-options is the safest way to ensure that correct values  are  passed  to  the
       rebooting kernel.

       The optional initrd-image is the initrd image to be used during boot.

       It's  also possible to invoke kexec without an option parameter. In that case, kexec loads
       the specified kernel and then invokes shutdown(1).  If the shutdown scripts of your  Linux
       distribution  support  kexec-based rebooting, they then call kexec -e just before actually
       rebooting the machine. That way, the machine does a clean shutdown including all  shutdown
       scripts.

EXAMPLE

       For  example,  if the kernel image you want to reboot to is /boot/vmlinux, the contents of
       /proc/cmdline is root=/dev/hda1, and the path to the  initrd  is  /boot/initrd,  then  you
       would use the following command to load the kernel:

              kexec -l /boot/vmlinux --append=root=/dev/hda1 --initrd=/boot/initrd

       After this kernel is loaded, it can be booted to at any time using the command:

              kexec -e

OPTIONS

       -e (--exec)
              Run  the  currently  loaded kernel. Note that it will reboot into the loaded kernel
              without calling shutdown(8).

       -f (--force)
              Force an immediate kexec call, do not call shutdown(8)  (contrary  to  the  default
              action  without  any  option parameter). This option performs the same actions like
              executing -l and -e in one call.

       -h (--help)
              Open a help file for kexec.

       -l (--load) kernel
              Load the specified kernel into the current kernel.

       -p (--load-panic)
              Load the new kernel for use on panic.

       -t (--type=type)
              Specify that the new kernel is of this type.

       -u (--unload)
              Unload the current kexec target kernel. If a capture kernel is being unloaded  then
              specify -p with -u.

       -v (--version)
              Return the version number of the installed utility.

       -x (--no-ifdown)
              Shut  down the running kernel, but restore the interface on reload. (If this option
              is used, it must be specified last.)

       --mem-min=addr
              Specify the lowest memory address addr to load code into.

       --mem-max=addr
              Specify the highest memory address addr to load code into.

SUPPORTED KERNEL FILE TYPES AND OPTIONS

       Beoboot-x86

              --args-elf
                     Pass ELF boot notes.

              --args-linux
                     Pass Linux kernel style options.

              -d  (--debug)
                     Enable debugging messages.

              --real-mode
                     Use the kernel's real mode entry point.

       elf-x86

              --append=string
                     Append string to the kernel command line.

              --command-line=string
                     Set the kernel command line to string.

              --reuse-cmdline
                     Use the command line from the running system. When a panic kernel is loaded,
                     it  strips the crashkernel parameter automatically. The BOOT_IMAGE parameter
                     is also stripped.

              --initrd=file
                     Use file as the kernel's initial ramdisk.

              --ramdisk=file
                     Use file as the kernel's initial ramdisk.

       bzImage-x86

              --append=string
                     Append string to the kernel command line.

              --command-line=string
                     Set the kernel command line to string.

              --reuse-cmdline
                     Use the command line from the running system. When a panic kernel is loaded,
                     it  strips the crashkernel parameter automatically. The BOOT_IMAGE parameter
                     is also stripped.

              --initrd=file
                     Use file as the kernel's initial ramdisk.

              --ramdisk=file
                     Use file as the kernel's initial ramdisk.

              --real-mode
                     Use real-mode entry point.

       multiboot-x86

              --command-line=string
                     Set the kernel command line to string.

              --reuse-cmdline
                     Use the command line from the running system. When a panic kernel is loaded,
                     it  strips the crashkernel parameter automatically. The BOOT_IMAGE parameter
                     is also stripped.

              --module=mod arg1 arg2 ...
                     Load module mod with command-line arguments arg1 arg2  ...   This  parameter
                     can be specified multiple times.

ARCHITECTURE OPTIONS

       --console-serial
              Enable the serial console.

       --console-vga
              Enable the VGA console.

       --elf32-core-headers
              Prepare core headers in ELF32 format.

       --elf64-core-headers
              Prepare core headers in ELF64 format.

       --reset-vga
              Attempt to reset a standard VGA device.

       --serial=port
              Specify the serial port for debug output.

       --serial-baud=baud_rate
              Specify the baud rate of the serial port.