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.\" $FreeBSD$ 26.\" 27.Dd June 20, 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 amd64 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_CPUID_COUNT 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 the following structure: 91.Bd -literal 92typedef struct { 93 int level; /* CPUID level */ 94 uint32_t data[4]; 95} cpuctl_cpuid_args_t; 96.Ed 97It is equivalent to the 98.Dv CPUCTL_CPUID_COUNT 99request with 100.Va level_type 101set to 0. 102.It Dv CPUCTL_CPUID_COUNT Fa cpuctl_cpuid_count_args_t *args 103Retrieve CPUID information. 104Arguments are supplied in the following structure: 105.Bd -literal 106typedef struct { 107 int level; /* CPUID level */ 108 int level_type; /* CPUID level type */ 109 uint32_t data[4]; 110} cpuctl_cpuid_count_args_t; 111.Ed 112The 113.Va level 114field indicates the CPUID level to retrieve, 115it is loaded into the 116.Va %eax 117register before the CPUID instruction is executed, 118The 119.Va level_type 120field indicates the CPUID level type to retrieve, 121it is loaded into the 122.Va %ecx 123register. 124.Pp 125The 126.Va data 127field is used to store the received CPUID data. 128That is, 129.Va data[0] 130contains the value of 131.Va %eax 132register after the CPUID instruction is executed, 133.Va data[1] 134is for 135.Va %ebx , 136.Va data[2] 137for 138.Va %ecx , 139and 140.Va data[3] 141for 142.Va %edx . 143.It Dv CPUCTL_UPDATE cpuctl_update_args_t *args 144Update CPU firmware (microcode). 145The structure is defined in 146.In sys/cpuctl.h 147as: 148.Bd -literal 149typedef struct { 150 void *data; 151 size_t size; 152} cpuctl_update_args_t; 153.Ed 154.Pp 155The 156.Va data 157field should point to the firmware image of size 158.Va size . 159.El 160.Pp 161For additional information refer to 162.Pa cpuctl.h . 163.Sh RETURN VALUES 164.Bl -tag -width Er 165.It Bq Er ENXIO 166The operation requested is not supported by the device (e.g., unsupported 167architecture or the CPU is disabled). 168.It Bq Er EINVAL 169Incorrect request was supplied, or microcode image is not correct. 170.It Bq Er ENOMEM 171No physical memory was available to complete the request. 172.It Bq Er EFAULT 173The firmware image address points outside the process address space. 174.El 175.Sh FILES 176.Bl -tag -width /dev/cpuctl -compact 177.It Pa /dev/cpuctl 178.El 179.Sh SEE ALSO 180.Xr hwpmc 4 , 181.Xr cpucontrol 8 182.Sh HISTORY 183The 184.Nm 185driver first appeared in 186.Fx 7.2 . 187.Sh AUTHORS 188The 189.Nm 190module and this manual page were written by 191.An Stanislav Sedov Aq Mt stas@FreeBSD.org . 192.Sh BUGS 193Yes, probably, report if any. 194