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.\" Copyright (c) 2006-2008 Stanislav Sedov <stas@FreeBSD.org>
.\" 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.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
.\"
.\" $FreeBSD$
.\"
.Dd June 30, 2009
.Dt CPUCTL 4
.Os
.Sh NAME
.Nm cpuctl
.Nd cpuctl pseudo device
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your kernel
configuration file:
.Bd -ragged -offset indent
.Cd "device cpuctl"
.Ed
.Pp
Alternatively, to load the driver as a module
at boot time, place the following in
.Xr loader.conf 5 :
.Bd -literal -offset indent
cpuctl_load="YES"
.Ed
.Sh DESCRIPTION
The special device
.Pa /dev/cpuctl
presents interface to the system CPU.
It provides functionality to retrieve
CPUID information, read/write machine specific registers (MSR) and perform
CPU firmware updates.
.Pp
For each CPU present in the system, the special device
.Pa /dev/cpuctl%d
with the appropriate index will be created.
For multicore CPUs such a
special device will be created for each core.
.Pp
Currently, only i386 and amd64 processors are
supported.
.Sh IOCTL INTERFACE
All of the supported operations are invoked using the
.Xr ioctl 2
system call.
Currently, the following ioctls are defined:
.Bl -tag -width CPUCTL_UPDATE
.It Dv CPUCTL_RDMSR Fa cpuctl_msr_args_t *args
.It Dv CPUCTL_WRMSR Fa cpuctl_msr_args_t *args
Read/write CPU machine specific register.
The
.Vt cpuctl_msr_args_t
structure is defined in
.In sys/cpuctl.h
as:
.Pp
.Bd -literal
typedef struct {
int msr; /* MSR to read */
uint64_t data;
} cpuctl_msr_args_t;
.Ed
.It Dv CPUCTL_MSRSBIT Fa cpuctl_msr_args_t *args
.It Dv CPUCTL_MSRCBIT Fa cpuctl_msr_args_t *args
Set/clear MSR bits according to the mask given in the
.Va data
field.
.It Dv CPUCTL_CPUID Fa cpuctl_cpuid_args_t *args
Retrieve CPUID information.
Arguments are supplied in
the following struct:
.Pp
.Bd -literal
typedef struct {
int level; /* CPUID level */
uint32_t data[4];
} cpuctl_cpuid_args_t;
.Ed
.Pp
The
.Va level
field indicates the CPUID level to retrieve information for, while the
.Va data
field is used to store the received CPUID data.
.It Dv CPUCTL_UPDATE cpuctl_update_args_t *args
Update CPU firmware (microcode).
The structure is defined in
.In sys/cpuctl.h
as:
.Pp
.Bd -literal
typedef struct {
void *data;
size_t size;
} cpuctl_update_args_t;
.Ed
.Pp
The
.Va data
field should point to the firmware image of size
.Va size .
.El
.Pp
For additional information refer to
.Pa cpuctl.h .
.Sh RETURN VALUES
.Bl -tag -width Er
.It Bq Er ENXIO
The operation requested is not supported by the device (e.g. unsupported
architecture or the CPU is disabled)
.It Bq Er EINVAL
Incorrect request was supplied, or microcode image is not correct.
.It Bq Er ENOMEM
No physical memory was available to complete the request.
.It Bq Er EFAULT
The firmware image address points outside the process address space.
.El
.Sh FILES
.Bl -tag -width /dev/cpuctl -compact
.It Pa /dev/cpuctl
.El
.Sh SEE ALSO
.Xr hwpmc 4 ,
.Xr cpucontrol 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 7.2 .
.Sh BUGS
Yes, probably, report if any.
.Sh AUTHORS
The
.Nm
module and this manual page were written by
.An Stanislav Sedov Aq stas@FreeBSD.org .
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