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Diffstat (limited to 'static/openbsd/man4/man4.i386/mem.4')
| -rw-r--r-- | static/openbsd/man4/man4.i386/mem.4 | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/static/openbsd/man4/man4.i386/mem.4 b/static/openbsd/man4/man4.i386/mem.4 new file mode 100644 index 00000000..9b31ab72 --- /dev/null +++ b/static/openbsd/man4/man4.i386/mem.4 @@ -0,0 +1,87 @@ +.\" $OpenBSD: mem.4,v 1.13 2024/03/22 12:29:33 jsg Exp $ +.\" +.\" Copyright (c) 1991 The Regents of the University of California. +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" from: @(#)mem.4 5.3 (Berkeley) 5/2/91 +.\" +.Dd $Mdocdate: March 22 2024 $ +.Dt MEM 4 i386 +.Os +.Sh NAME +.Nm mem , +.Nm kmem +.Nd memory files +.Sh DESCRIPTION +The special file +.Pa /dev/mem +is an interface to the physical memory of the computer. +Byte offsets in this file are interpreted as physical memory addresses. +Reading and writing this file is equivalent to reading and writing +memory itself. +Only offsets within the bounds of +.Pa /dev/mem +are allowed. +.Pp +Kernel virtual memory is accessed through the interface +.Pa /dev/kmem +in the same manner as +.Pa /dev/mem . +Only kernel virtual addresses that are currently mapped to memory are allowed. +.Pp +On ISA the I/O memory space begins at physical address +.Li 0x000a0000 +and runs to +.Li 0x00100000 . +The per-process data size for the current process is +.Dv UPAGES +long, and ends at virtual address +.Li 0xfe000000 . +.Pp +Even with sufficient file system permissions, +these devices can only be opened when the +.Xr securelevel 7 +is insecure or when the +.Va kern.allowkmem +.Xr sysctl 2 +variable is set. +.Sh FILES +.Bl -tag -width Pa -compact +.It Pa /dev/mem +.It Pa /dev/kmem +.El +.Sh SEE ALSO +.Xr mtrr 4 , +.Xr securelevel 7 +.Sh HISTORY +The +.Pa /dev/mem +file appeared in +.At v1 , +.Pa /dev/kmem +appeared in +.At v5 . |
