diff options
| -rw-r--r-- | drivers/resctrl/mpam_devices.c | 2 | ||||
| -rw-r--r-- | drivers/resctrl/mpam_internal.h | 41 |
2 files changed, 43 insertions, 0 deletions
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 3d9b87a9727a..dcbc9cf5581d 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -19,6 +19,7 @@ #include <linux/platform_device.h> #include <linux/printk.h> #include <linux/srcu.h> +#include <linux/spinlock.h> #include <linux/types.h> #include <linux/workqueue.h> @@ -740,6 +741,7 @@ static struct mpam_msc *do_mpam_msc_drv_probe(struct platform_device *pdev) if (err) return ERR_PTR(err); + mpam_mon_sel_lock_init(msc); msc->id = pdev->id; msc->pdev = pdev; INIT_LIST_HEAD_RCU(&msc->all_msc_list); diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h index 768a58a3ab27..97f02cf92d7a 100644 --- a/drivers/resctrl/mpam_internal.h +++ b/drivers/resctrl/mpam_internal.h @@ -10,6 +10,7 @@ #include <linux/llist.h> #include <linux/mutex.h> #include <linux/srcu.h> +#include <linux/spinlock.h> #include <linux/types.h> #define MPAM_MSC_MAX_NUM_RIS 16 @@ -65,12 +66,52 @@ struct mpam_msc { */ struct mutex part_sel_lock; + /* + * mon_sel_lock protects access to the MSC hardware registers that are + * affected by MPAMCFG_MON_SEL, and the mbwu_state. + * Access to mon_sel is needed from both process and interrupt contexts, + * but is complicated by firmware-backed platforms that can't make any + * access unless they can sleep. + * Always use the mpam_mon_sel_lock() helpers. + * Accesses to mon_sel need to be able to fail if they occur in the wrong + * context. + * If needed, take msc->probe_lock first. + */ + raw_spinlock_t _mon_sel_lock; + unsigned long _mon_sel_flags; + void __iomem *mapped_hwpage; size_t mapped_hwpage_sz; struct mpam_garbage garbage; }; +/* Returning false here means accesses to mon_sel must fail and report an error. */ +static inline bool __must_check mpam_mon_sel_lock(struct mpam_msc *msc) +{ + /* Locking will require updating to support a firmware backed interface */ + if (WARN_ON_ONCE(msc->iface != MPAM_IFACE_MMIO)) + return false; + + raw_spin_lock_irqsave(&msc->_mon_sel_lock, msc->_mon_sel_flags); + return true; +} + +static inline void mpam_mon_sel_unlock(struct mpam_msc *msc) +{ + raw_spin_unlock_irqrestore(&msc->_mon_sel_lock, msc->_mon_sel_flags); +} + +static inline void mpam_mon_sel_lock_held(struct mpam_msc *msc) +{ + lockdep_assert_held_once(&msc->_mon_sel_lock); +} + +static inline void mpam_mon_sel_lock_init(struct mpam_msc *msc) +{ + raw_spin_lock_init(&msc->_mon_sel_lock); +} + struct mpam_class { /* mpam_components in this class */ struct list_head components; |