From: James Morse Date: Fri, 13 Mar 2026 14:46:11 +0000 (+0000) Subject: arm_mpam: resctrl: Call resctrl_init() on platforms that can support resctrl X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=fb481ec08699e9daf08ab839a79ab37b1bcca94d;p=thirdparty%2Fkernel%2Flinux.git 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 Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Zeng Heng Tested-by: Punit Agrawal Tested-by: Jesse Chick Reviewed-by: Zeng Heng Reviewed-by: Shaopeng Tan Reviewed-by: Jonathan Cameron Reviewed-by: Gavin Shan Co-developed-by: Ben Horgan Signed-off-by: Ben Horgan Signed-off-by: James Morse --- diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 0c97f77087221..37b31a1cf376c 100644 --- 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 85b2b99263601..68906c6ebfb01 100644 --- 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 777ecdc2d0f85..a9938006d0e6e 100644 --- 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;