xref: /freebsd/lib/libkvm/kvm_kerndisp.3 (revision 1da7f3f6f72b2245e458fc7195733268ae4a1136)
1.\"
2.\" Copyright (c) 2020 Leandro Lupori <luporl@FreeBSD.org>
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\"    notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\"    notice, this list of conditions and the following disclaimer in the
11.\"    documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
25.Dd February 5, 2020
26.Dt KVM_KERNDISP 3
27.Os
28.Sh NAME
29.Nm kvm_kerndisp
30.Nd get kernel displacement
31.Sh LIBRARY
32.Lb libkvm
33.Sh SYNOPSIS
34.In kvm.h
35.Ft kssize_t
36.Fn kvm_kerndisp "kvm_t *kd"
37.Sh DESCRIPTION
38.Fn kvm_kerndisp
39returns the number of bytes by which the kernel referenced by
40.Fa kd
41is displaced.
42This is the difference between the kernel's base virtual address at run time
43and the kernel base virtual address specified in the kernel image file.
44.Pp
45Note that if the kernel is moved to a lower memory address,
46the displacement will be negative.
47.Sh RETURN VALUES
48.Fn kvm_kerndisp
49returns the number of bytes by which the kernel is displaced.
50If the kernel is not displaced or if it is not possible to find the
51displacement then 0 is returned.
52.Sh SEE ALSO
53.Xr kvm 3 ,
54.Xr kvm_close 3 ,
55.Xr kvm_open 3
56