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CPUCONTROL(8)		FreeBSD	System Manager's Manual		 CPUCONTROL(8)

NAME
     cpucontrol	-- control utility for the cpuctl(4) device

SYNOPSIS
     cpucontrol	[-v] -m	msr device
     cpucontrol	[-v] -m	msr=value device
     cpucontrol	[-v] -m	msr&=mask device
     cpucontrol	[-v] -m	msr|=mask device
     cpucontrol	[-v] -i	level device
     cpucontrol	[-v] -i	level,level_type device
     cpucontrol	[-vn] [-d datadir] -u device
     cpucontrol	-e device

DESCRIPTION
     The cpucontrol utility can	be used	to read	and write arbitrary machine-
     specific CPU registers via	the cpuctl(4) special device.  It can also be
     used to apply CPU firmware	updates.

     The following options are available:

     -d	datadir
	     Directory paths where to look for microcode images.  The option
	     can be specified multiple times.  The paths are added in order of
	     the options appearance on the command line, default directories
	     are appended after	the user-supplied paths.

     -n	     Do	not look for the microcode images in the standard directories.
	     Currently standard	directory to look for the microcode update
	     files is /usr/local/share/cpucontrol.

     -m	msr  Show value	of the specified MSR.  MSR register number should be
	     given as a	hexadecimal number.  The high word is printed first,
	     then the low word is printed second.

     -m	msr=value
	     Store the value in	the specified MSR register.  The value argu-
	     ment can be prefixed with ~ operator.  In this case the inverted
	     value of argument will be stored in the register.

     -m	msr&=mask
	     Store the result of bitwise AND operation between mask and	the
	     current MSR value in the MSR register.  The mask argument can be
	     prefixed with ~ operator.	In this	case the inverted value	of
	     mask will be used.

     -m	msr|=mask
	     Store the result of bitwise OR operation between mask and the
	     current MSR value in the MSR register.  The mask argument can be
	     prefixed with ~ operator.	In this	case the inverted value	of
	     mask will be used.

     -i	level
	     Retrieve CPUID info.  Level should	be given as a hex number.

     -i	level,level_type
	     Retrieve CPUID info.  Level and level_type	should be given	as hex
	     numbers.

     -u	     Apply CPU firmware	updates.  The cpucontrol utility will walk
	     through the configured data directories and apply all firmware
	     updates available for this	CPU.

     -e	     Re-evaluate the kernel flags indicating the present CPU features.
	     This command is typically executed	after a	firmware update	was
	     applied which changes information reported	by the CPUID instruc-
	     tion.

	     Only execute the -e command after the microcode update was
	     applied to	all CPUs in the	system.	 The kernel does not operate
	     correctly if the features of processors are not identical.

     -v	     Increase the verbosity level.

     -h	     Show help message.

EXIT STATUS
     The cpucontrol utility exits 0 on success,	and >0 if an error occurs.

EXAMPLES
     The command

     ``cpucontrol -m 0x10 /dev/cpuctl0''

     will read the contents of TSC MSR from CPU	0.

     To	set the	CPU 0 TSC MSR register value to	0x1 issue

     ``cpucontrol -m 0x10=0x1 /dev/cpuctl0''.

     The following command will	clear the second bit of	TSC register:

     ``cpucontrol -m 0x10&=~0x02 /dev/cpuctl0''.

     The following command will	set the	forth and second bit of	TSC register:

     ``cpucontrol -m 0x10|=0x0a	/dev/cpuctl0''.

     The command

     ``cpucontrol -i 0x1 /dev/cpuctl1''

     will retrieve the CPUID level 0x1 from CPU	1.

     To	perform	firmware updates on CPU	0 from images located at
     /usr/local/share/cpuctl use the following command:

     ``cpucontrol -nd /usr/local/share/cpuctl -u /dev/cpuctl0''

SEE ALSO
     cpuctl(4)

HISTORY
     The cpucontrol utility first appeared in FreeBSD 7.2.

AUTHORS
     The cpucontrol utility and	this manual page was written by	Stanislav
     Sedov <stas@FreeBSD.org>.

FreeBSD	11.2			January	5, 2018			  FreeBSD 11.2

NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | EXAMPLES | SEE ALSO | HISTORY | AUTHORS

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