hwpmc: probe the RAPL unit MSR instead of faulting on it

The RAPL probe read MSR_RAPL_POWER_UNIT with a bare rdmsr().  RAPL is not
enumerated by CPUID on either vendor and the register is absent on older
Intel and AMD parts and under a hypervisor that does not emulate it, so
the read raises #GP and loading hwpmc panics the machine.

Read it with rdmsr_safe() and return ENXIO when it is not there, as this
function already does for the energy MSRs.  Both callers already drop the
class when the probe fails.

Fixes:		a99d04f39dab ("hwpmc: add RAPL energy-counter class (AMD + Intel)")
Assisted-by:	Claude Code (Opus 5)

0 files changed, 0 insertions, 0 deletions