amdmsr —
access MSRs on certain AMD Geode LX systems
amdmsr0 at mainbus?
The
amdmsr device provides access to the
Model Specific Registers (MSRs) on systems with an AMD Geode LX CPU and
graphics processor.
MSRs can be read or written via
ioctl() calls
performed on
/dev/amdmsr. Declarations and
data types are to be found in
<machine/amdmsr.h>.
Read or write requests are performed using:
struct amdmsr_req {
u_int32_t addr; /* 32-bit MSR address */
u_int64_t val; /* 64-bit MSR value */
};
The
RDMSR ioctl is used to read an MSR
register.
The
WRMSR ioctl is used to write an MSR
register.
ioctl(2)
amdmsr support was added in
OpenBSD 4.4.
![[OpenBSD]](/openbsd.gif){kind=small}