diff options
| -rw-r--r-- | drivers/resctrl/mpam_devices.c | 176 | ||||
| -rw-r--r-- | drivers/resctrl/mpam_internal.h | 5 |
2 files changed, 180 insertions, 1 deletions
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index f1dcf9bb14f2..51284f55ae9b 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -4,8 +4,10 @@ #define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__ #include <linux/acpi.h> +#include <linux/atomic.h> #include <linux/arm_mpam.h> #include <linux/cacheinfo.h> +#include <linux/cpu.h> #include <linux/cpumask.h> #include <linux/device.h> #include <linux/errno.h> @@ -17,6 +19,7 @@ #include <linux/printk.h> #include <linux/srcu.h> #include <linux/types.h> +#include <linux/workqueue.h> #include "mpam_internal.h" @@ -36,6 +39,25 @@ struct srcu_struct mpam_srcu; */ static atomic_t mpam_num_msc; +static int mpam_cpuhp_state; +static DEFINE_MUTEX(mpam_cpuhp_state_lock); + +/* + * mpam is enabled once all devices have been probed from CPU online callbacks, + * scheduled via this work_struct. If access to an MSC depends on a CPU that + * was not brought online at boot, this can happen surprisingly late. + */ +static DECLARE_WORK(mpam_enable_work, &mpam_enable); + +/* + * All mpam error interrupts indicate a software bug. On receipt, disable the + * driver. + */ +static DECLARE_WORK(mpam_broken_work, &mpam_disable); + +/* When mpam is disabled, the printed reason to aid debugging */ +static char *mpam_disable_reason; + /* * 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 @@ -106,6 +128,21 @@ static void mpam_free_garbage(void) } } +static u32 __mpam_read_reg(struct mpam_msc *msc, u16 reg) +{ + WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); + + return readl_relaxed(msc->mapped_hwpage + reg); +} + +static inline u32 _mpam_read_partsel_reg(struct mpam_msc *msc, u16 reg) +{ + lockdep_assert_held_once(&msc->part_sel_lock); + return __mpam_read_reg(msc, reg); +} + +#define mpam_read_partsel_reg(msc, reg) _mpam_read_partsel_reg(msc, MPAMF_##reg) + static struct mpam_class * mpam_class_alloc(u8 level_idx, enum mpam_class_types type) { @@ -413,6 +450,86 @@ int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx, return err; } +static int mpam_msc_hw_probe(struct mpam_msc *msc) +{ + u64 idr; + struct device *dev = &msc->pdev->dev; + + lockdep_assert_held(&msc->probe_lock); + + idr = __mpam_read_reg(msc, MPAMF_AIDR); + if ((idr & MPAMF_AIDR_ARCH_MAJOR_REV) != MPAM_ARCHITECTURE_V1) { + dev_err_once(dev, "MSC does not match MPAM architecture v1.x\n"); + return -EIO; + } + + msc->probed = true; + + return 0; +} + +static int mpam_cpu_online(unsigned int cpu) +{ + return 0; +} + +/* Before mpam is enabled, try to probe new MSC */ +static int mpam_discovery_cpu_online(unsigned int cpu) +{ + int err = 0; + struct mpam_msc *msc; + bool new_device_probed = false; + + guard(srcu)(&mpam_srcu); + list_for_each_entry_srcu(msc, &mpam_all_msc, all_msc_list, + srcu_read_lock_held(&mpam_srcu)) { + if (!cpumask_test_cpu(cpu, &msc->accessibility)) + continue; + + mutex_lock(&msc->probe_lock); + if (!msc->probed) + err = mpam_msc_hw_probe(msc); + mutex_unlock(&msc->probe_lock); + + if (err) + break; + new_device_probed = true; + } + + if (new_device_probed && !err) + schedule_work(&mpam_enable_work); + if (err) { + mpam_disable_reason = "error during probing"; + schedule_work(&mpam_broken_work); + } + + return err; +} + +static int mpam_cpu_offline(unsigned int cpu) +{ + return 0; +} + +static void mpam_register_cpuhp_callbacks(int (*online)(unsigned int online), + int (*offline)(unsigned int offline), + char *name) +{ + mutex_lock(&mpam_cpuhp_state_lock); + if (mpam_cpuhp_state) { + cpuhp_remove_state(mpam_cpuhp_state); + mpam_cpuhp_state = 0; + } + + mpam_cpuhp_state = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, name, online, + offline); + if (mpam_cpuhp_state <= 0) { + pr_err("Failed to register cpuhp callbacks"); + mpam_cpuhp_state = 0; + } + mutex_unlock(&mpam_cpuhp_state_lock); +} + /* * An MSC can control traffic from a set of CPUs, but may only be accessible * from a (hopefully wider) set of CPUs. The common reason for this is power @@ -549,7 +666,8 @@ static int mpam_msc_drv_probe(struct platform_device *pdev) } if (atomic_add_return(1, &mpam_num_msc) == fw_num_msc) - pr_info("Discovered all MSCs\n"); + mpam_register_cpuhp_callbacks(mpam_discovery_cpu_online, NULL, + "mpam:drv_probe"); return 0; } @@ -562,6 +680,62 @@ static struct platform_driver mpam_msc_driver = { .remove = mpam_msc_drv_remove, }; +static void mpam_enable_once(void) +{ + mpam_register_cpuhp_callbacks(mpam_cpu_online, mpam_cpu_offline, + "mpam:online"); + + pr_info("MPAM enabled\n"); +} + +void mpam_disable(struct work_struct *ignored) +{ + struct mpam_msc *msc, *tmp; + + mutex_lock(&mpam_cpuhp_state_lock); + if (mpam_cpuhp_state) { + cpuhp_remove_state(mpam_cpuhp_state); + mpam_cpuhp_state = 0; + } + mutex_unlock(&mpam_cpuhp_state_lock); + + mutex_lock(&mpam_list_lock); + list_for_each_entry_safe(msc, tmp, &mpam_all_msc, all_msc_list) + mpam_msc_destroy(msc); + mutex_unlock(&mpam_list_lock); + mpam_free_garbage(); + + pr_err_once("MPAM disabled due to %s\n", mpam_disable_reason); +} + +/* + * Enable mpam once all devices have been probed. + * Scheduled by mpam_discovery_cpu_online() once all devices have been created. + * Also scheduled when new devices are probed when new CPUs come online. + */ +void mpam_enable(struct work_struct *work) +{ + static atomic_t once; + struct mpam_msc *msc; + bool all_devices_probed = true; + + /* Have we probed all the hw devices? */ + guard(srcu)(&mpam_srcu); + list_for_each_entry_srcu(msc, &mpam_all_msc, all_msc_list, + srcu_read_lock_held(&mpam_srcu)) { + mutex_lock(&msc->probe_lock); + if (!msc->probed) + all_devices_probed = false; + mutex_unlock(&msc->probe_lock); + + if (!all_devices_probed) + break; + } + + if (all_devices_probed && !atomic_fetch_inc(&once)) + mpam_enable_once(); +} + static int __init mpam_msc_driver_init(void) { if (!system_supports_mpam()) diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h index 51f791cc207b..4e1538d29783 100644 --- a/drivers/resctrl/mpam_internal.h +++ b/drivers/resctrl/mpam_internal.h @@ -48,6 +48,7 @@ struct mpam_msc { * properties become read-only and the lists are protected by SRCU. */ struct mutex probe_lock; + bool probed; unsigned long ris_idxs; u32 ris_max; @@ -137,6 +138,10 @@ struct mpam_msc_ris { extern struct srcu_struct mpam_srcu; extern struct list_head mpam_classes; +/* Scheduled work callback to enable mpam once all MSC have been probed */ +void mpam_enable(struct work_struct *work); +void mpam_disable(struct work_struct *work); + int mpam_get_cpumask_from_cache_id(unsigned long cache_id, u32 cache_level, cpumask_t *affinity); |