1.\" Copyright (c) 2006-2008 Stanislav Sedov <stas@FreeBSD.org> 2.\" All rights reserved. 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.\" $FreeBSD: release/10.0.0/share/man/man4/cpuctl.4 235317 2012-05-12 03:25:46Z gjb $ 26.\" 27.Dd November 18, 2014 28.Dt CPUCTL 4 29.Os 30.Sh NAME 31.Nm cpuctl 32.Nd cpuctl pseudo device 33.Sh SYNOPSIS 34To compile this driver into the kernel, 35place the following lines in your kernel 36configuration file: 37.Bd -ragged -offset indent 38.Cd "device cpuctl" 39.Ed 40.Pp 41Alternatively, to load the driver as a module 42at boot time, place the following in 43.Xr loader.conf 5 : 44.Bd -literal -offset indent 45cpuctl_load="YES" 46.Ed 47.Sh DESCRIPTION 48The special device 49.Pa /dev/cpuctl 50presents interface to the system CPU. 51It provides functionality to retrieve 52CPUID information, read/write machine specific registers (MSR) and perform 53CPU firmware updates. 54.Pp 55For each CPU present in the system, the special device 56.Pa /dev/cpuctl%d 57with the appropriate index will be created. 58For multicore CPUs such a 59special device will be created for each core. 60.Pp 61Currently, only i386 and x86_64 processors are 62supported. 63.Sh IOCTL INTERFACE 64All of the supported operations are invoked using the 65.Xr ioctl 2 66system call. 67Currently, the following ioctls are defined: 68.Bl -tag -width CPUCTL_UPDATE 69.It Dv CPUCTL_RDMSR Fa cpuctl_msr_args_t *args 70.It Dv CPUCTL_WRMSR Fa cpuctl_msr_args_t *args 71Read/write CPU machine specific register. 72The 73.Vt cpuctl_msr_args_t 74structure is defined in 75.In sys/cpuctl.h 76as: 77.Bd -literal 78typedef struct { 79 int msr; /* MSR to read */ 80 uint64_t data; 81} cpuctl_msr_args_t; 82.Ed 83.It Dv CPUCTL_MSRSBIT Fa cpuctl_msr_args_t *args 84.It Dv CPUCTL_MSRCBIT Fa cpuctl_msr_args_t *args 85Set/clear MSR bits according to the mask given in the 86.Va data 87field. 88.It Dv CPUCTL_CPUID Fa cpuctl_cpuid_args_t *args 89Retrieve CPUID information. 90Arguments are supplied in 91the following struct: 92.Bd -literal 93typedef struct { 94 int level; /* CPUID level */ 95 uint32_t data[4]; 96} cpuctl_cpuid_args_t; 97.Ed 98.Pp 99The 100.Va level 101field indicates the CPUID level to retrieve information for, while the 102.Va data 103field is used to store the received CPUID data. 104.It Dv CPUCTL_UPDATE cpuctl_update_args_t *args 105Update CPU firmware (microcode). 106The structure is defined in 107.In sys/cpuctl.h 108as: 109.Bd -literal 110typedef struct { 111 void *data; 112 size_t size; 113} cpuctl_update_args_t; 114.Ed 115.Pp 116The 117.Va data 118field should point to the firmware image of size 119.Va size . 120.El 121.Pp 122For additional information refer to 123.Pa cpuctl.h . 124.Sh FILES 125.Bl -tag -width /dev/cpuctl -compact 126.It Pa /dev/cpuctl 127.El 128.Sh ERRORS 129.Bl -tag -width Er 130.It Bq Er ENXIO 131The operation requested is not supported by the device (e.g., unsupported 132architecture or the CPU is disabled). 133.It Bq Er EINVAL 134Incorrect request was supplied, or microcode image is not correct. 135.It Bq Er ENOMEM 136No physical memory was available to complete the request. 137.It Bq Er EFAULT 138The firmware image address points outside the process address space. 139.El 140.Sh SEE ALSO 141.\".Xr hwpmc 4 , 142.Xr cpucontrol 8 143.Sh HISTORY 144The 145.Nm 146driver first appeared in 147.Fx 7.2 . 148.Sh AUTHORS 149The 150.Nm 151module and this manual page were written by 152.An Stanislav Sedov Aq Mt stas@FreeBSD.org . 153.Sh BUGS 154Yes, probably, report if any. 155