dlopen.3: tfix

[thirdparty/man-pages.git] / man4 / mem.4

diff --git a/man4/mem.4 b/man4/mem.4
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--- a/man4/mem.4
+++ b/man4/mem.4
@@ -1,5 +1,7 @@
-.\" Copyright (c) 1993 Michael Haardt (michael@moria.de), Fri Apr  2 11:32:09 MET DST 1993
+.\" Copyright (c) 1993 Michael Haardt (michael@moria.de),
+.\"     Fri Apr  2 11:32:09 MET DST 1993
 .\"
+.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
 .\" This is free documentation; you can redistribute it and/or
 .\" modify it under the terms of the GNU General Public License as
 .\" published by the Free Software Foundation; either version 2 of
@@ -16,64 +18,83 @@
 .\" GNU General Public License for more details.
 .\"
 .\" You should have received a copy of the GNU General Public
-.\" License along with this manual; if not, write to the Free
-.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
-.\" USA.
+.\" License along with this manual; if not, see
+.\" <http://www.gnu.org/licenses/>.
+.\" %%%LICENSE_END
 .\"
 .\" Modified Sat Jul 24 16:59:10 1993 by Rik Faith (faith@cs.unc.edu)
-.TH MEM 4 1992-11-21 "Linux" "Linux Programmer's Manual"
+.TH MEM 4 2015-01-02 "Linux" "Linux Programmer's Manual"
 .SH NAME
 mem, kmem, port \- system memory, kernel memory and system ports
 .SH DESCRIPTION
-\fBMem\fP is a character device file
-that is an image of the main memory of the
-computer.  It may be used, for example, to examine (and even patch) the
-system.
-.LP
-Byte addresses in mem are interpreted as physical memory addresses.
-References to non-existent locations cause errors to be returned.
-.LP
+.IR /dev/mem
+is a character device file
+that is an image of the main memory of the computer.
+It may be used, for example, to examine (and even patch) the system.
+.PP
+Byte addresses in
+.IR /dev/mem
+are interpreted as physical memory addresses.
+References to nonexistent locations cause errors to be returned.
+.PP
 Examining and patching is likely to lead to unexpected results
 when read-only or write-only bits are present.
-.LP
+.PP
+Since Linux 2.6.26, and depending on the architecture, the
+.B CONFIG_STRICT_DEVMEM
+kernel configuration option limits the areas
+which can be accessed through this file.
+For example: on x86, RAM access is not allowed but accessing
+memory-mapped PCI regions is.
+.PP
 It is typically created by:
-.RS
-.sp
-mknod -m 660 /dev/mem c 1 1
-.br
-chown root:mem /dev/mem
-.sp
-.RE
-.LP
-The file kmem is the same as mem, except that the kernel virtual memory
+.PP
+.in +4n
+.EX
+mknod \-m 660 /dev/mem c 1 1
+chown root:kmem /dev/mem
+.EE
+.in
+.PP
+The file
+.IR /dev/kmem
+is the same as
+.IR /dev/mem ,
+except that the kernel virtual memory
 rather than physical memory is accessed.
-.LP
+Since Linux 2.6.26, this file is available only if the
+.B CONFIG_DEVKMEM
+kernel configuration option is enabled.
+.PP
 It is typically created by:
-.RS
-.sp
-mknod -m 640 /dev/kmem c 1 2
-.br
-chown root:mem /dev/kmem
-.sp
-.RE
-.LP
-\fBPort\fP is similar to mem, but the IO ports are accessed.
-.LP
+.PP
+.in +4n
+.EX
+mknod \-m 640 /dev/kmem c 1 2
+chown root:kmem /dev/kmem
+.EE
+.in
+.PP
+.IR /dev/port
+is similar to
+.IR /dev/mem ,
+but the I/O ports are accessed.
+.PP
 It is typically created by:
-.RS
-.sp
-mknod -m 660 /dev/port c 1 4
-.br
-chown root:mem /dev/port
-.sp
-.RE
+.PP
+.in +4n
+.EX
+mknod \-m 660 /dev/port c 1 4
+chown root:kmem /dev/port
+.EE
+.in
 .SH FILES
 .I /dev/mem
 .br
 .I /dev/kmem
 .br
 .I /dev/port
-.SH "SEE ALSO"
+.SH SEE ALSO
 .BR chown (1),
 .BR mknod (1),
 .BR ioperm (2)