freebsd-dev/usr.sbin/cpucontrol/cpucontrol.8
Stanislav Sedov e085f869d5 - Add cpuctl(4) pseudo-device driver to provide access to some low-level
features of CPUs like reading/writing machine-specific registers,
  retrieving cpuid data, and updating microcode.
- Add cpucontrol(8) utility, that provides userland access to
  the features of cpuctl(4).
- Add subsequent manpages.

The cpuctl(4) device operates as follows. The pseudo-device node cpuctlX
is created for each cpu present in the systems. The pseudo-device minor
number corresponds to the cpu number in the system. The cpuctl(4) pseudo-
device allows a number of ioctl to be preformed, namely RDMSR/WRMSR/CPUID
and UPDATE. The first pair alows the caller to read/write machine-specific
registers from the correspondent CPU. cpuid data could be retrieved using
the CPUID call, and microcode updates are applied via UPDATE.

The permissions are inforced based on the pseudo-device file permissions.
RDMSR/CPUID will be allowed when the caller has read access to the device
node, while WRMSR/UPDATE will be granted only when the node is opened
for writing. There're also a number of priv(9) checks.

The cpucontrol(8) utility is intened to provide userland access to
the cpuctl(4) device features. The utility also allows one to apply
cpu microcode updates.

Currently only Intel and AMD cpus are supported and were tested.

Approved by:	kib
Reviewed by:	rpaulo, cokane, Peter Jeremy
MFC after:	1 month
2008-08-08 16:26:53 +00:00

117 lines
3.2 KiB
Groff

.\" Copyright (c) 2006, 2008 Stanislav Sedov <stas@FreeBSD.org>.
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" $FreeBSD$
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.Dd August 4, 2008
.Dt CPUCONTROL 8
.Os
.Sh NAME
.Nm cpucontrol
.Nd control utility for the
.Xr cpuctl 4
device.
.Sh SYNOPSIS
.Nm
.Op Fl vh
.Fl m Ar msr Ns Op = Ns Ar value
.Bk
.Ar device
.Ek
.Nm
.Op Fl vh
.Fl i Ar level
.Bk
.Ar device
.Ek
.Nm
.Op Fl vh
.Op Fl d Ar datadir
.Fl u
.Bk
.Ar device
.Ek
.Sh DESCRIPTION
The
.Nm
utility can be used to read and write an arbitrary machine-specific
CPU registers via
.Xr cpuctl 4
controlled special device and apply the CPU firmware updates.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl d Ar datadir
Where to look for microcode images. The option can be specified multiple times.
.It Fl m Ar msr Ns Op = Ns Ar value
Read/write the specified MSR. Both the MSR and the value should be given as a hex number.
.It Fl i Ar level
Retrieve CPUID info. Level should be given as a hex number.
.It Fl u
Apply CPU firmware updates. The
.Nm
utility will walk through the configured data directories
and will apply all firmware patches available for this CPU.
.It Fl v
Increase the verbosity level.
.It Fl h
Show help message.
.El
.Sh EXIT STATUS
The
.Nm
utility exits 0 on success, and >0 if an error occurs.
.Sh EXAMPLES
The command
.Pp
.Dq Li "cpucontrol -m 0x10 /dev/cpuctl0"
.Pp
will read the contents of TSC MSR from CPU 0.
.Pp
To set the CPU 0 TSC MSR register value to 0x1 issue
.Pp
.Dq Li "cpucontrol -m 0x10=0x1 /dev/cpuctl0"
.Pp
.Pp
The command
.Pp
.Dq Li "cpucontrol -i 0x1 /dev/cpuctl1"
.Pp
will retrieve the CPUID level 0x1 from CPU 1.
.Pp
To perform firmware updated on CPU 0 from images located at
.Pa /usr/local/share/cpuctl/
use the following command:
.Pp
.Dq Li "cpucontrol -d /usr/local/share/cpuctl/ -u /dev/cpuctl0"
.Sh SEE ALSO
.Xr cpuctl 4
.Sh BUGS
Yes, probably, report if any.
.Sh AUTHORS
The
.Nm
utility and this manual page was written by
.An Stanislav Sedov Aq stas@FreeBSD.org .