NAME

SYNOPSIS

Alternatively, to load the driver as a module at boot time, place the following in loader.conf(5):

cpuctl_load="YES"

DESCRIPTION

For each CPU present in the system, the special device /dev/cpuctl%d with the appropriate index will be created. For multicore CPUs such a special device will be created for each core.

Currently, only i386 and amd64 processors are supported.

IOCTL INTERFACE

CPUCTL_RDMSR cpuctl_msr_args_t *args

 

CPUCTL_WRMSR cpuctl_msr_args_t *args

Read/write CPU machine specific register. The cpuctl_msr_args_t structure is defined in <sys/cpuctl.h> as:

typedef struct {
	int		msr;	/* MSR to read */
	uint64_t	data;
} cpuctl_msr_args_t;
    

CPUCTL_MSRSBIT cpuctl_msr_args_t *args

 

CPUCTL_MSRCBIT cpuctl_msr_args_t *args

Set/clear MSR bits according to the mask given in the data field.

CPUCTL_CPUID cpuctl_cpuid_args_t *args

Retrieve CPUID information. Arguments are supplied in the following structure:

typedef struct {
	int		level;		/* CPUID level */
	uint32_t	data[4];
} cpuctl_cpuid_args_t;
    

It is equivalent to the CPUCTL_CPUID_COUNT request with level_type set to 0.

CPUCTL_CPUID_COUNT cpuctl_cpuid_count_args_t *args

Retrieve CPUID information. Arguments are supplied in the following structure:

typedef struct {
	int		level;		/* CPUID level */
	int		level_type;	/* CPUID level type */
	uint32_t	data[4];
} cpuctl_cpuid_count_args_t;
    

The level field indicates the CPUID level to retrieve, it is loaded into the %eax register before the CPUID instruction is executed, The level_type field indicates the CPUID level type to retrieve, it is loaded into the %ecx register.

The data field is used to store the received CPUID data. That is, data[0] contains the value of %eax register after the CPUID instruction is executed, data[1] is for %ebx, data[2] for %ecx, and data[3] for %edx.

CPUCTL_UPDATE cpuctl_update_args_t *args

Update CPU firmware (microcode). The structure is defined in <sys/cpuctl.h> as:

typedef struct {
	void	*data;
	size_t	size;
} cpuctl_update_args_t;
    

The data field should point to the firmware image of size size.

For additional information refer to cpuctl.h.

FILES

/dev/cpuctl

 

ERRORS

[ENXIO]

The operation requested is not supported by the device (e.g., unsupported architecture or the CPU is disabled).

[EINVAL]

Incorrect request was supplied, or microcode image is not correct.

[ENOMEM]

No physical memory was available to complete the request.

[EFAULT]

The firmware image address points outside the process address space.

SEE ALSO

HISTORY

AUTHORS

BUGS