arm_mpam: resctrl: Call resctrl_init() on platforms that can support resctrl

Now that MPAM links against resctrl, call resctrl_init() to register the
filesystem and setup resctrl's structures.

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>

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 0c97f770872216c722199feac91d7f0c081fe1f0..37b31a1cf376ce9d50925b7bca96f363e4f85064 100644 (file)
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -73,6 +73,14 @@ static DECLARE_WORK(mpam_broken_work, &mpam_disable);
 /* When mpam is disabled, the printed reason to aid debugging */
 static char *mpam_disable_reason;
 
+/*
+ * Whether resctrl has been setup. Used by cpuhp in preference to
+ * mpam_is_enabled(). The disable call after an error interrupt makes
+ * mpam_is_enabled() false before the cpuhp callbacks are made.
+ * Reads/writes should hold mpam_cpuhp_state_lock, (or be cpuhp callbacks).
+ */
+static bool mpam_resctrl_enabled;
+
 /*
  * An MSC is a physical container for controls and monitors, each identified by
  * their RIS index. These share a base-address, interrupts and some MMIO
@@ -1619,7 +1627,7 @@ static int mpam_cpu_online(unsigned int cpu)
                        mpam_reprogram_msc(msc);
        }
 
-       if (mpam_is_enabled())
+       if (mpam_resctrl_enabled)
                return mpam_resctrl_online_cpu(cpu);
 
        return 0;
@@ -1665,7 +1673,7 @@ static int mpam_cpu_offline(unsigned int cpu)
 {
        struct mpam_msc *msc;
 
-       if (mpam_is_enabled())
+       if (mpam_resctrl_enabled)
                mpam_resctrl_offline_cpu(cpu);
 
        guard(srcu)(&mpam_srcu);
@@ -2526,6 +2534,7 @@ static void mpam_enable_once(void)
        }
 
        static_branch_enable(&mpam_enabled);
+       mpam_resctrl_enabled = true;
        mpam_register_cpuhp_callbacks(mpam_cpu_online, mpam_cpu_offline,
                                      "mpam:online");
 
@@ -2585,24 +2594,39 @@ static void mpam_reset_class(struct mpam_class *class)
 void mpam_disable(struct work_struct *ignored)
 {
        int idx;
+       bool do_resctrl_exit;
        struct mpam_class *class;
        struct mpam_msc *msc, *tmp;
 
+       if (mpam_is_enabled())
+               static_branch_disable(&mpam_enabled);
+
        mutex_lock(&mpam_cpuhp_state_lock);
        if (mpam_cpuhp_state) {
                cpuhp_remove_state(mpam_cpuhp_state);
                mpam_cpuhp_state = 0;
        }
+
+       /*
+        * Removing the cpuhp state called mpam_cpu_offline() and told resctrl
+        * all the CPUs are offline.
+        */
+       do_resctrl_exit = mpam_resctrl_enabled;
+       mpam_resctrl_enabled = false;
        mutex_unlock(&mpam_cpuhp_state_lock);
 
-       static_branch_disable(&mpam_enabled);
+       if (do_resctrl_exit)
+               mpam_resctrl_exit();
 
        mpam_unregister_irqs();
 
        idx = srcu_read_lock(&mpam_srcu);
        list_for_each_entry_srcu(class, &mpam_classes, classes_list,
-                                srcu_read_lock_held(&mpam_srcu))
+                                srcu_read_lock_held(&mpam_srcu)) {
                mpam_reset_class(class);
+               if (do_resctrl_exit)
+                       mpam_resctrl_teardown_class(class);
+       }
        srcu_read_unlock(&mpam_srcu, idx);
 
        mutex_lock(&mpam_list_lock);

diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index 85b2b99263601dbf86f520e800f20c6dfc8ecf42..68906c6ebfb01053192bc7d92f39f13499644e36 100644 (file)
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h
@@ -431,12 +431,16 @@ int mpam_get_cpumask_from_cache_id(unsigned long cache_id, u32 cache_level,
 
 #ifdef CONFIG_RESCTRL_FS
 int mpam_resctrl_setup(void);
+void mpam_resctrl_exit(void);
 int mpam_resctrl_online_cpu(unsigned int cpu);
 void mpam_resctrl_offline_cpu(unsigned int cpu);
+void mpam_resctrl_teardown_class(struct mpam_class *class);
 #else
 static inline int mpam_resctrl_setup(void) { return 0; }
+static inline void mpam_resctrl_exit(void) { }
 static inline int mpam_resctrl_online_cpu(unsigned int cpu) { return 0; }
 static inline void mpam_resctrl_offline_cpu(unsigned int cpu) { }
+static inline void mpam_resctrl_teardown_class(struct mpam_class *class) { }
 #endif /* CONFIG_RESCTRL_FS */
 
 /*

diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
index 777ecdc2d0f85acc696619eb506c20ad4ba13d42..a9938006d0e6ec5532adb185d9bb15437cce076b 100644 (file)
--- a/drivers/resctrl/mpam_resctrl.c
+++ b/drivers/resctrl/mpam_resctrl.c
@@ -69,6 +69,12 @@ static bool cdp_enabled;
 static bool cacheinfo_ready;
 static DECLARE_WAIT_QUEUE_HEAD(wait_cacheinfo_ready);
 
+/*
+ * If resctrl_init() succeeded, resctrl_exit() can be used to remove support
+ * for the filesystem in the event of an error.
+ */
+static bool resctrl_enabled;
+
 bool resctrl_arch_alloc_capable(void)
 {
        struct mpam_resctrl_res *res;
@@ -360,6 +366,9 @@ static int resctrl_arch_mon_ctx_alloc_no_wait(enum resctrl_event_id evtid)
 {
        struct mpam_resctrl_mon *mon = &mpam_resctrl_counters[evtid];
 
+       if (!mpam_is_enabled())
+               return -EINVAL;
+
        if (!mon->class)
                return -EINVAL;
 
@@ -402,6 +411,9 @@ static void resctrl_arch_mon_ctx_free_no_wait(enum resctrl_event_id evtid,
 {
        struct mpam_resctrl_mon *mon = &mpam_resctrl_counters[evtid];
 
+       if (!mpam_is_enabled())
+               return;
+
        if (!mon->class)
                return;
 
@@ -488,6 +500,9 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain_hdr *hdr,
 
        resctrl_arch_rmid_read_context_check();
 
+       if (!mpam_is_enabled())
+               return -EINVAL;
+
        if (eventid >= QOS_NUM_EVENTS || !mon->class)
                return -EINVAL;
 
@@ -1162,6 +1177,9 @@ int resctrl_arch_update_one(struct rdt_resource *r, struct rdt_ctrl_domain *d,
        lockdep_assert_cpus_held();
        lockdep_assert_irqs_enabled();
 
+       if (!mpam_is_enabled())
+               return -EINVAL;
+
        /*
         * No need to check the CPU as mpam_apply_config() doesn't care, and
         * resctrl_arch_update_domains() relies on this.
@@ -1227,6 +1245,9 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid)
        lockdep_assert_cpus_held();
        lockdep_assert_irqs_enabled();
 
+       if (!mpam_is_enabled())
+               return -EINVAL;
+
        list_for_each_entry_rcu(d, &r->ctrl_domains, hdr.list) {
                for (enum resctrl_conf_type t = 0; t < CDP_NUM_TYPES; t++) {
                        struct resctrl_staged_config *cfg = &d->staged_config[t];
@@ -1619,7 +1640,11 @@ int mpam_resctrl_setup(void)
                return -EOPNOTSUPP;
        }
 
-       /* TODO: call resctrl_init() */
+       err = resctrl_init();
+       if (err)
+               return err;
+
+       WRITE_ONCE(resctrl_enabled, true);
 
        return 0;
 
@@ -1629,6 +1654,42 @@ internal_error:
        return err;
 }
 
+void mpam_resctrl_exit(void)
+{
+       if (!READ_ONCE(resctrl_enabled))
+               return;
+
+       WRITE_ONCE(resctrl_enabled, false);
+       resctrl_exit();
+}
+
+/*
+ * The driver is detaching an MSC from this class, if resctrl was using it,
+ * pull on resctrl_exit().
+ */
+void mpam_resctrl_teardown_class(struct mpam_class *class)
+{
+       struct mpam_resctrl_res *res;
+       enum resctrl_res_level rid;
+       struct mpam_resctrl_mon *mon;
+       enum resctrl_event_id eventid;
+
+       might_sleep();
+
+       for_each_mpam_resctrl_control(res, rid) {
+               if (res->class == class) {
+                       res->class = NULL;
+                       break;
+               }
+       }
+       for_each_mpam_resctrl_mon(mon, eventid) {
+               if (mon->class == class) {
+                       mon->class = NULL;
+                       break;
+               }
+       }
+}
+
 static int __init __cacheinfo_ready(void)
 {
        cacheinfo_ready = true;