When attempting to reset the PMU state for either a NULL PMU or a PMU
implementation without a reset function, return NOTIFY_DONE from the CPU
notifier as we don't care about the hotplug event.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The current practice of registering the cpu hotplug notifier at PMU
registration time won't be safe with multiple PMUs, as we'll repeatedly
attempt to register the notifier. This has the unfortunate effect of
silently corrupting the notifier list, leading to boot stalling.

Instead, register the notifier at init time. Its sanity checks will
prevent anything bad from happening if the notifier is called before we
have any PMUs registered.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The arm_pmu functions have wildly varied parameters which can often be
derived from struct perf_event.

This patch changes the arm_pmu function prototypes so that struct
perf_event pointers are passed in preference to fields that can be
derived from the event.
Signed-off-by: NSudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Supporting multiple, heterogeneous CPU PMUs requires us to allocate the
arm_pmu structures dynamically as the devices are probed.

This patch removes the static structure definitions for each CPU PMU
type and instead passes pointers to the PMU-specific init functions.
Signed-off-by: NSudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This patch moves the CPU-specific IRQ registration and parsing code into
the CPU PMU backend. This is required because a PMU may have more than
one interrupt, which in turn can be either PPI (per-cpu) or SPI
(requiring strict affinity setting at the interrupt distributor).
Signed-off-by: NSudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
[will: cosmetic edits and reworked interrupt dispatching]
Signed-off-by: NWill Deacon <will.deacon@arm.com>

This patch moves the CPU-specific PMU handling code out of perf_event.c
and into perf_event_cpu.c.
Signed-off-by: NWill Deacon <will.deacon@arm.com>