The PMU appears to have a separate register for filtering 'guest'
exception levels (i.e. EL1 and !ELIsInHost(EL0)) which has the same
layout as PMCR1_EL1. Conveniently, there exists a VHE register alias
(PMCR1_EL12) that can be used to configure it.
Support guest events by programming the EL12 register with the intended
guest kernel/userspace filters. Limit support for guest events to VHE
(i.e. kernel running at EL2), as it avoids involving KVM to context
switch PMU registers. VHE is the only supported mode on M* parts anyway,
so this isn't an actual feature limitation.
Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-3-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Add a new, weird and wonderful driver for the equally weird Apple
PMU HW. Although the PMU itself is functional, we don't know much
about the events yet, so this can be considered as yet another
random number generator...
Nonetheless, it can reliably count at least cycles and instructions
in the usually wonky big-little way. For anything else, it of course
supports raw event numbers.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
As we are about to have a PMU driver, move the PMU bits from the AIC
driver into a common include file.
Reviewed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Marc Zyngier <maz@kernel.org>
