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.Dd June 20, 2014 26.Dt CPUCTL 4 27.Os 28.Sh NAME 29.Nm cpuctl 30.Nd cpuctl pseudo device 31.Sh SYNOPSIS 32To compile this driver into the kernel, 33place the following lines in your kernel 34configuration file: 35.Bd -ragged -offset indent 36.Cd "device cpuctl" 37.Ed 38.Pp 39Alternatively, to load the driver as a module 40at boot time, place the following in 41.Xr loader.conf 5 : 42.Bd -literal -offset indent 43cpuctl_load="YES" 44.Ed 45.Sh DESCRIPTION 46The special device 47.Pa /dev/cpuctl 48presents interface to the system CPU. 49It provides functionality to retrieve 50CPUID information, read/write machine specific registers (MSR) and perform 51CPU firmware updates. 52.Pp 53For each CPU present in the system, the special device 54.Pa /dev/cpuctl%d 55with the appropriate index will be created. 56For multicore CPUs such a 57special device will be created for each core. 58.Pp 59Currently, only i386 and amd64 processors are 60supported. 61.Sh IOCTL INTERFACE 62All of the supported operations are invoked using the 63.Xr ioctl 2 64system call. 65Currently, the following ioctls are defined: 66.Bl -tag -width CPUCTL_CPUID_COUNT 67.It Dv CPUCTL_RDMSR Fa cpuctl_msr_args_t *args 68.It Dv CPUCTL_WRMSR Fa cpuctl_msr_args_t *args 69Read/write CPU machine specific register. 70The 71.Vt cpuctl_msr_args_t 72structure is defined in 73.In sys/cpuctl.h 74as: 75.Bd -literal 76typedef struct { 77 int msr; /* MSR to read */ 78 uint64_t data; 79} cpuctl_msr_args_t; 80.Ed 81.It Dv CPUCTL_MSRSBIT Fa cpuctl_msr_args_t *args 82.It Dv CPUCTL_MSRCBIT Fa cpuctl_msr_args_t *args 83Set/clear MSR bits according to the mask given in the 84.Va data 85field. 86.It Dv CPUCTL_CPUID Fa cpuctl_cpuid_args_t *args 87Retrieve CPUID information. 88Arguments are supplied in the following structure: 89.Bd -literal 90typedef struct { 91 int level; /* CPUID level */ 92 uint32_t data[4]; 93} cpuctl_cpuid_args_t; 94.Ed 95It is equivalent to the 96.Dv CPUCTL_CPUID_COUNT 97request with 98.Va level_type 99set to 0. 100.It Dv CPUCTL_CPUID_COUNT Fa cpuctl_cpuid_count_args_t *args 101Retrieve CPUID information. 102Arguments are supplied in the following structure: 103.Bd -literal 104typedef struct { 105 int level; /* CPUID level */ 106 int level_type; /* CPUID level type */ 107 uint32_t data[4]; 108} cpuctl_cpuid_count_args_t; 109.Ed 110The 111.Va level 112field indicates the CPUID level to retrieve, 113it is loaded into the 114.Va %eax 115register before the CPUID instruction is executed, 116The 117.Va level_type 118field indicates the CPUID level type to retrieve, 119it is loaded into the 120.Va %ecx 121register. 122.Pp 123The 124.Va data 125field is used to store the received CPUID data. 126That is, 127.Va data[0] 128contains the value of 129.Va %eax 130register after the CPUID instruction is executed, 131.Va data[1] 132is for 133.Va %ebx , 134.Va data[2] 135for 136.Va %ecx , 137and 138.Va data[3] 139for 140.Va %edx . 141.It Dv CPUCTL_UPDATE cpuctl_update_args_t *args 142Update CPU firmware (microcode). 143The structure is defined in 144.In sys/cpuctl.h 145as: 146.Bd -literal 147typedef struct { 148 void *data; 149 size_t size; 150} cpuctl_update_args_t; 151.Ed 152.Pp 153The 154.Va data 155field should point to the firmware image of size 156.Va size . 157.El 158.Pp 159For additional information refer to 160.Pa cpuctl.h . 161.Sh FILES 162.Bl -tag -width /dev/cpuctl -compact 163.It Pa /dev/cpuctl 164.El 165.Sh ERRORS 166.Bl -tag -width Er 167.It Bq Er ENXIO 168The operation requested is not supported by the device (e.g., unsupported 169architecture or the CPU is disabled). 170.It Bq Er EINVAL 171Incorrect request was supplied, or microcode image is not correct. 172.It Bq Er ENOMEM 173No physical memory was available to complete the request. 174.It Bq Er EFAULT 175The firmware image address points outside the process address space. 176.El 177.Sh SEE ALSO 178.Xr hwpmc 4 , 179.Xr cpucontrol 8 180.Sh HISTORY 181The 182.Nm 183driver first appeared in 184.Fx 7.2 . 185.Sh AUTHORS 186The 187.Nm 188module and this manual page were written by 189.An Stanislav Sedov Aq Mt stas@FreeBSD.org . 190.Sh BUGS 191Yes, probably, report if any. 192