KEXEC_LOAD
Section: Linux Programmer's Manual (2)
Updated: 2014-08-19
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NAME
kexec_load - load a new kernel for later execution
SYNOPSIS
#include <linux/kexec.h>
long kexec_load(unsigned long entry, unsigned long nr_segments,
struct kexec_segment *segments, unsigned long flags);
Note:
There is no glibc wrapper for this system call; see NOTES.
DESCRIPTION
The
kexec_load()
system call loads a new kernel that can be executed later by
reboot(2).
The
flags
argument is a bit mask that controls the operation of the call.
The following values can be specified in
flags:
- KEXEC_ON_CRASH (since Linux 2.6.13)
-
Execute the new kernel automatically on a system crash.
- KEXEC_PRESERVE_CONTEXT (since Linux 2.6.27)
-
Preserve the system hardware and
software states before executing the new kernel.
This could be used for system suspend.
This flag is available only if the kernel was configured with
CONFIG_KEXEC_JUMP,
and is effective only if
nr_segments
is greater than 0.
The high-order bits (corresponding to the mask 0xffff0000) of
flags
contain the architecture of the to-be-executed kernel.
Specify (OR) the constant
KEXEC_ARCH_DEFAULT
to use the current architecture,
or one of the following architecture constants
KEXEC_ARCH_386,
KEXEC_ARCH_68K,
KEXEC_ARCH_X86_64,
KEXEC_ARCH_PPC,
KEXEC_ARCH_PPC64,
KEXEC_ARCH_IA_64,
KEXEC_ARCH_ARM,
KEXEC_ARCH_S390,
KEXEC_ARCH_SH,
KEXEC_ARCH_MIPS,
and
KEXEC_ARCH_MIPS_LE.
The architecture must be executable on the CPU of the system.
The
entry
argument is the physical entry address in the kernel image.
The
nr_segments
argument is the number of segments pointed to by the
segments
pointer;
the kernel imposes an (arbitrary) limit of 16 on the number of segments.
The
segments
argument is an array of
kexec_segment
structures which define the kernel layout:
struct kexec_segment {
void *buf; /* Buffer in user space */
size_t bufsz; /* Buffer length in user space */
void *mem; /* Physical address of kernel */
size_t memsz; /* Physical address length */
};
The kernel image defined by
segments
is copied from the calling process into previously reserved memory.
RETURN VALUE
On success,
kexec_load()
returns 0.
On error, -1 is returned and
errno
is set to indicate the error.
ERRORS
- EBUSY
-
Another crash kernel is already being loaded
or a crash kernel is already in use.
- EINVAL
-
flags
is invalid; or
nr_segments
is too large
- EPERM
-
The caller does not have the
CAP_SYS_BOOT
capability.
VERSIONS
The
kexec_load()
system call first appeared in Linux 2.6.13.
CONFORMING TO
This system call is Linux-specific.
NOTES
Currently, there is no glibc support for
kexec_load().
Call it using
syscall(2).
The required constants are in the Linux kernel source file
linux/kexec.h,
which is not currently exported to glibc.
Therefore, these constants must be defined manually.
This system call is available only if the kernel was configured with
CONFIG_KEXEC.
SEE ALSO
reboot(2),
syscall(2)
COLOPHON
This page is part of release 3.74 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
http://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-