arm_mpam: resctrl: Add boilerplate cpuhp and domain allocation

resctrl has its own data structures to describe its resources. We can't use
these directly as we play tricks with the 'MBA' resource, picking the MPAM
controls or monitors that best apply. We may export the same component as
both L3 and MBA.

Add mpam_resctrl_res[] as the array of class->resctrl mappings we are
exporting, and add the cpuhp hooks that allocated and free the resctrl
domain structures. Only the mpam control feature are considered here and
monitor support will be added later.

While we're here, plumb in a few other obvious things.

CONFIG_ARM_CPU_RESCTRL is used to allow this code to be built even though
it can't yet be linked against resctrl.

Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Zeng Heng <zengheng4@huawei.com>
Tested-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
Tested-by: Jesse Chick <jessechick@os.amperecomputing.com>
Reviewed-by: Zeng Heng <zengheng4@huawei.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Co-developed-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>

Author: James Morse

drivers/resctrl/Makefile

@@ -1,4 +1,5 @@
 obj-$(CONFIG_ARM64_MPAM_DRIVER)			+= mpam.o
 mpam-y						+= mpam_devices.o
+mpam-$(CONFIG_ARM_CPU_RESCTRL)			+= mpam_resctrl.o
 
 ccflags-$(CONFIG_ARM64_MPAM_DRIVER_DEBUG)	+= -DDEBUG

drivers/resctrl/mpam_devices.c

@@ -1612,6 +1612,9 @@ static int mpam_cpu_online(unsigned int cpu)
 			mpam_reprogram_msc(msc);
 	}
 
+	if (mpam_is_enabled())
+		return mpam_resctrl_online_cpu(cpu);
+
 	return 0;
 }
 
@@ -1655,6 +1658,9 @@ static int mpam_cpu_offline(unsigned int cpu)
 {
 	struct mpam_msc *msc;
 
+	if (mpam_is_enabled())
+		mpam_resctrl_offline_cpu(cpu);
+
 	guard(srcu)(&mpam_srcu);
 	list_for_each_entry_srcu(msc, &mpam_all_msc, all_msc_list,
 				 srcu_read_lock_held(&mpam_srcu)) {
@@ -2500,6 +2506,12 @@ static void mpam_enable_once(void)
 	mutex_unlock(&mpam_list_lock);
 	cpus_read_unlock();
 
+	if (!err) {
+		err = mpam_resctrl_setup();
+		if (err)
+			pr_err("Failed to initialise resctrl: %d\n", err);
+	}
+
 	if (err) {
 		mpam_disable_reason = "Failed to enable.";
 		schedule_work(&mpam_broken_work);

drivers/resctrl/mpam_internal.h

@@ -12,6 +12,7 @@
 #include <linux/jump_label.h>
 #include <linux/llist.h>
 #include <linux/mutex.h>
+#include <linux/resctrl.h>
 #include <linux/spinlock.h>
 #include <linux/srcu.h>
 #include <linux/types.h>
@@ -333,6 +334,16 @@ struct mpam_msc_ris {
 	struct mpam_garbage	garbage;
 };
 
+struct mpam_resctrl_dom {
+	struct mpam_component		*ctrl_comp;
+	struct rdt_ctrl_domain		resctrl_ctrl_dom;
+};
+
+struct mpam_resctrl_res {
+	struct mpam_class	*class;
+	struct rdt_resource	resctrl_res;
+};
+
 static inline int mpam_alloc_csu_mon(struct mpam_class *class)
 {
 	struct mpam_props *cprops = &class->props;
@@ -387,6 +398,16 @@ void mpam_msmon_reset_mbwu(struct mpam_component *comp, struct mon_cfg *ctx);
 int mpam_get_cpumask_from_cache_id(unsigned long cache_id, u32 cache_level,
 				   cpumask_t *affinity);
 
+#ifdef CONFIG_RESCTRL_FS
+int mpam_resctrl_setup(void);
+int mpam_resctrl_online_cpu(unsigned int cpu);
+void mpam_resctrl_offline_cpu(unsigned int cpu);
+#else
+static inline int mpam_resctrl_setup(void) { return 0; }
+static inline int mpam_resctrl_online_cpu(unsigned int cpu) { return 0; }
+static inline void mpam_resctrl_offline_cpu(unsigned int cpu) { }
+#endif /* CONFIG_RESCTRL_FS */
+
 /*
  * MPAM MSCs have the following register layout. See:
  * Arm Memory System Resource Partitioning and Monitoring (MPAM) System