arm64: perf: Move PMUv3 driver to drivers/perf

Having the ARM PMUv3 driver sitting in arch/arm64/kernel is getting
in the way of being able to use perf on ARMv8 cores running a 32bit
kernel, such as 32bit KVM guests.

This patch moves it into drivers/perf/arm_pmuv3.c, with an include
file in include/linux/perf/arm_pmuv3.h. The only thing left in
arch/arm64 is some mundane perf stuff.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Zaid Al-Bassam <zalbassam@google.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230317195027.3746949-2-zalbassam@google.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm64/kernel/Makefile

@@ -45,7 +45,6 @@ obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace.o entry-ftrace.o
 obj-$(CONFIG_MODULES)			+= module.o
 obj-$(CONFIG_ARM64_MODULE_PLTS)		+= module-plts.o
 obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o perf_callchain.o
-obj-$(CONFIG_HW_PERF_EVENTS)		+= perf_event.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
 obj-$(CONFIG_CPU_PM)			+= sleep.o suspend.o
 obj-$(CONFIG_CPU_IDLE)			+= cpuidle.o

drivers/perf/Kconfig

@@ -100,6 +100,17 @@ config ARM_SMMU_V3_PMU
 	   through the SMMU and allow the resulting information to be filtered
 	   based on the Stream ID of the corresponding master.
 
+config ARM_PMUV3
+	depends on HW_PERF_EVENTS && ARM64
+	bool "ARM PMUv3 support" if !ARM64
+	default y
+	  help
+	  Say y if you want to use the ARM performance monitor unit (PMU)
+	  version 3. The PMUv3 is the CPU performance monitors on ARMv8
+	  (aarch32 and aarch64) systems that implement the PMUv3
+	  architecture.
+	  Currently, PMUv3 is only supported on aarch64 (arm64)
+
 config ARM_DSU_PMU
 	tristate "ARM DynamIQ Shared Unit (DSU) PMU"
 	depends on ARM64

drivers/perf/Makefile

@@ -5,6 +5,7 @@ obj-$(CONFIG_ARM_CMN) += arm-cmn.o
 obj-$(CONFIG_ARM_DSU_PMU) += arm_dsu_pmu.o
 obj-$(CONFIG_ARM_PMU) += arm_pmu.o arm_pmu_platform.o
 obj-$(CONFIG_ARM_PMU_ACPI) += arm_pmu_acpi.o
+obj-$(CONFIG_ARM_PMUV3) += arm_pmuv3.o
 obj-$(CONFIG_ARM_SMMU_V3_PMU) += arm_smmuv3_pmu.o
 obj-$(CONFIG_FSL_IMX8_DDR_PMU) += fsl_imx8_ddr_perf.o
 obj-$(CONFIG_HISI_PMU) += hisilicon/

arch/arm64/kernel/perf_event.c → drivers/perf/arm_pmuv3.c

@@ -20,6 +20,7 @@
 #include <linux/kvm_host.h>
 #include <linux/of.h>
 #include <linux/perf/arm_pmu.h>
+#include <linux/perf/arm_pmuv3.h>
 #include <linux/platform_device.h>
 #include <linux/sched_clock.h>
 #include <linux/smp.h>

include/kvm/arm_pmu.h

@@ -8,7 +8,7 @@
 #define __ASM_ARM_KVM_PMU_H
 
 #include <linux/perf_event.h>
-#include <asm/perf_event.h>
+#include <linux/perf/arm_pmuv3.h>
 
 #define ARMV8_PMU_CYCLE_IDX		(ARMV8_PMU_MAX_COUNTERS - 1)