perf/amd/uncore: Allow the driver to be built as a module

Add support to build the AMD uncore driver as a module.

This is in order to facilitate development without having
to reboot the kernel in most cases.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210817221048.88063-8-kim.phillips@amd.com

arch/x86/events/Kconfig

@@ -34,4 +34,14 @@ config PERF_EVENTS_AMD_POWER
 	  (CPUID Fn8000_0007_EDX[12]) interface to calculate the
 	  average power consumption on Family 15h processors.
 
+config PERF_EVENTS_AMD_UNCORE
+	tristate "AMD Uncore performance events"
+	depends on PERF_EVENTS && CPU_SUP_AMD
+	default y
+	help
+	  Include support for AMD uncore performance events for use with
+	  e.g., perf stat -e amd_l3/.../,amd_df/.../.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called 'amd-uncore'.
 endmenu

arch/x86/events/amd/Makefile

 # SPDX-License-Identifier: GPL-2.0
-obj-$(CONFIG_CPU_SUP_AMD)		+= core.o uncore.o
+obj-$(CONFIG_CPU_SUP_AMD)		+= core.o
 obj-$(CONFIG_PERF_EVENTS_AMD_POWER)	+= power.o
 obj-$(CONFIG_X86_LOCAL_APIC)		+= ibs.o
+obj-$(CONFIG_PERF_EVENTS_AMD_UNCORE)	+= amd-uncore.o
+amd-uncore-objs				:= uncore.o
 ifdef CONFIG_AMD_IOMMU
 obj-$(CONFIG_CPU_SUP_AMD)		+= iommu.o
 endif
-

arch/x86/events/amd/uncore.c

@@ -347,6 +347,7 @@ static struct pmu amd_nb_pmu = {
 	.stop		= amd_uncore_stop,
 	.read		= amd_uncore_read,
 	.capabilities	= PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT,
+	.module		= THIS_MODULE,
 };
 
 static struct pmu amd_llc_pmu = {
@@ -360,6 +361,7 @@ static struct pmu amd_llc_pmu = {
 	.stop		= amd_uncore_stop,
 	.read		= amd_uncore_read,
 	.capabilities	= PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT,
+	.module		= THIS_MODULE,
 };
 
 static struct amd_uncore *amd_uncore_alloc(unsigned int cpu)
@@ -665,4 +667,28 @@ static int __init amd_uncore_init(void)
 
 	return ret;
 }
-device_initcall(amd_uncore_init);
+
+static void __exit amd_uncore_exit(void)
+{
+	cpuhp_remove_state(CPUHP_AP_PERF_X86_AMD_UNCORE_ONLINE);
+	cpuhp_remove_state(CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING);
+	cpuhp_remove_state(CPUHP_PERF_X86_AMD_UNCORE_PREP);
+
+	if (boot_cpu_has(X86_FEATURE_PERFCTR_LLC)) {
+		perf_pmu_unregister(&amd_llc_pmu);
+		free_percpu(amd_uncore_llc);
+		amd_uncore_llc = NULL;
+	}
+
+	if (boot_cpu_has(X86_FEATURE_PERFCTR_NB)) {
+		perf_pmu_unregister(&amd_nb_pmu);
+		free_percpu(amd_uncore_nb);
+		amd_uncore_nb = NULL;
+	}
+}
+
+module_init(amd_uncore_init);
+module_exit(amd_uncore_exit);
+
+MODULE_DESCRIPTION("AMD Uncore Driver");
+MODULE_LICENSE("GPL v2");