diff options
| -rw-r--r-- | drivers/resctrl/mpam_devices.c | 148 | ||||
| -rw-r--r-- | drivers/resctrl/mpam_internal.h | 6 | ||||
| -rw-r--r-- | include/linux/arm_mpam.h | 14 |
3 files changed, 167 insertions, 1 deletions
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 51284f55ae9b..3d9b87a9727a 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -6,6 +6,7 @@ #include <linux/acpi.h> #include <linux/atomic.h> #include <linux/arm_mpam.h> +#include <linux/bitfield.h> #include <linux/cacheinfo.h> #include <linux/cpu.h> #include <linux/cpumask.h> @@ -43,6 +44,15 @@ static int mpam_cpuhp_state; static DEFINE_MUTEX(mpam_cpuhp_state_lock); /* + * The smallest common values for any CPU or MSC in the system. + * Generating traffic outside this range will result in screaming interrupts. + */ +u16 mpam_partid_max; +u8 mpam_pmg_max; +static bool partid_max_init, partid_max_published; +static DEFINE_SPINLOCK(partid_max_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. @@ -143,6 +153,70 @@ static inline u32 _mpam_read_partsel_reg(struct mpam_msc *msc, u16 reg) #define mpam_read_partsel_reg(msc, reg) _mpam_read_partsel_reg(msc, MPAMF_##reg) +static void __mpam_write_reg(struct mpam_msc *msc, u16 reg, u32 val) +{ + WARN_ON_ONCE(reg + sizeof(u32) > msc->mapped_hwpage_sz); + WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); + + writel_relaxed(val, msc->mapped_hwpage + reg); +} + +static inline void _mpam_write_partsel_reg(struct mpam_msc *msc, u16 reg, u32 val) +{ + lockdep_assert_held_once(&msc->part_sel_lock); + __mpam_write_reg(msc, reg, val); +} + +#define mpam_write_partsel_reg(msc, reg, val) _mpam_write_partsel_reg(msc, MPAMCFG_##reg, val) + +static u64 mpam_msc_read_idr(struct mpam_msc *msc) +{ + u64 idr_high = 0, idr_low; + + lockdep_assert_held(&msc->part_sel_lock); + + idr_low = mpam_read_partsel_reg(msc, IDR); + if (FIELD_GET(MPAMF_IDR_EXT, idr_low)) + idr_high = mpam_read_partsel_reg(msc, IDR + 4); + + return (idr_high << 32) | idr_low; +} + +static void __mpam_part_sel_raw(u32 partsel, struct mpam_msc *msc) +{ + lockdep_assert_held(&msc->part_sel_lock); + + mpam_write_partsel_reg(msc, PART_SEL, partsel); +} + +static void __mpam_part_sel(u8 ris_idx, u16 partid, struct mpam_msc *msc) +{ + u32 partsel = FIELD_PREP(MPAMCFG_PART_SEL_RIS, ris_idx) | + FIELD_PREP(MPAMCFG_PART_SEL_PARTID_SEL, partid); + + __mpam_part_sel_raw(partsel, msc); +} + +int mpam_register_requestor(u16 partid_max, u8 pmg_max) +{ + guard(spinlock)(&partid_max_lock); + if (!partid_max_init) { + mpam_partid_max = partid_max; + mpam_pmg_max = pmg_max; + partid_max_init = true; + } else if (!partid_max_published) { + mpam_partid_max = min(mpam_partid_max, partid_max); + mpam_pmg_max = min(mpam_pmg_max, pmg_max); + } else { + /* New requestors can't lower the values */ + if (partid_max < mpam_partid_max || pmg_max < mpam_pmg_max) + return -EBUSY; + } + + return 0; +} +EXPORT_SYMBOL(mpam_register_requestor); + static struct mpam_class * mpam_class_alloc(u8 level_idx, enum mpam_class_types type) { @@ -450,9 +524,35 @@ int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx, return err; } +static struct mpam_msc_ris *mpam_get_or_create_ris(struct mpam_msc *msc, + u8 ris_idx) +{ + int err; + struct mpam_msc_ris *ris; + + lockdep_assert_held(&mpam_list_lock); + + if (!test_bit(ris_idx, &msc->ris_idxs)) { + err = mpam_ris_create_locked(msc, ris_idx, MPAM_CLASS_UNKNOWN, + 0, 0); + if (err) + return ERR_PTR(err); + } + + list_for_each_entry(ris, &msc->ris, msc_list) { + if (ris->ris_idx == ris_idx) + return ris; + } + + return ERR_PTR(-ENOENT); +} + static int mpam_msc_hw_probe(struct mpam_msc *msc) { u64 idr; + u16 partid_max; + u8 ris_idx, pmg_max; + struct mpam_msc_ris *ris; struct device *dev = &msc->pdev->dev; lockdep_assert_held(&msc->probe_lock); @@ -463,6 +563,40 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc) return -EIO; } + /* Grab an IDR value to find out how many RIS there are */ + mutex_lock(&msc->part_sel_lock); + idr = mpam_msc_read_idr(msc); + mutex_unlock(&msc->part_sel_lock); + + msc->ris_max = FIELD_GET(MPAMF_IDR_RIS_MAX, idr); + + /* Use these values so partid/pmg always starts with a valid value */ + msc->partid_max = FIELD_GET(MPAMF_IDR_PARTID_MAX, idr); + msc->pmg_max = FIELD_GET(MPAMF_IDR_PMG_MAX, idr); + + for (ris_idx = 0; ris_idx <= msc->ris_max; ris_idx++) { + mutex_lock(&msc->part_sel_lock); + __mpam_part_sel(ris_idx, 0, msc); + idr = mpam_msc_read_idr(msc); + mutex_unlock(&msc->part_sel_lock); + + partid_max = FIELD_GET(MPAMF_IDR_PARTID_MAX, idr); + pmg_max = FIELD_GET(MPAMF_IDR_PMG_MAX, idr); + msc->partid_max = min(msc->partid_max, partid_max); + msc->pmg_max = min(msc->pmg_max, pmg_max); + + mutex_lock(&mpam_list_lock); + ris = mpam_get_or_create_ris(msc, ris_idx); + mutex_unlock(&mpam_list_lock); + if (IS_ERR(ris)) + return PTR_ERR(ris); + } + + spin_lock(&partid_max_lock); + mpam_partid_max = min(mpam_partid_max, msc->partid_max); + mpam_pmg_max = min(mpam_pmg_max, msc->pmg_max); + spin_unlock(&partid_max_lock); + msc->probed = true; return 0; @@ -682,10 +816,20 @@ static struct platform_driver mpam_msc_driver = { static void mpam_enable_once(void) { + /* + * Once the cpuhp callbacks have been changed, mpam_partid_max can no + * longer change. + */ + spin_lock(&partid_max_lock); + partid_max_published = true; + spin_unlock(&partid_max_lock); + mpam_register_cpuhp_callbacks(mpam_cpu_online, mpam_cpu_offline, "mpam:online"); - pr_info("MPAM enabled\n"); + /* Use printk() to avoid the pr_fmt adding the function name. */ + printk(KERN_INFO "MPAM enabled with %u PARTIDs and %u PMGs\n", + mpam_partid_max + 1, mpam_pmg_max + 1); } void mpam_disable(struct work_struct *ignored) @@ -751,4 +895,6 @@ static int __init mpam_msc_driver_init(void) return platform_driver_register(&mpam_msc_driver); } + +/* Must occur after arm64_mpam_register_cpus() from arch_initcall() */ subsys_initcall(mpam_msc_driver_init); diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h index 4e1538d29783..768a58a3ab27 100644 --- a/drivers/resctrl/mpam_internal.h +++ b/drivers/resctrl/mpam_internal.h @@ -49,6 +49,8 @@ struct mpam_msc { */ struct mutex probe_lock; bool probed; + u16 partid_max; + u8 pmg_max; unsigned long ris_idxs; u32 ris_max; @@ -138,6 +140,10 @@ struct mpam_msc_ris { extern struct srcu_struct mpam_srcu; extern struct list_head mpam_classes; +/* System wide partid/pmg values */ +extern u16 mpam_partid_max; +extern u8 mpam_pmg_max; + /* 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); diff --git a/include/linux/arm_mpam.h b/include/linux/arm_mpam.h index 13a8ac5c2cbd..7f00c5285a32 100644 --- a/include/linux/arm_mpam.h +++ b/include/linux/arm_mpam.h @@ -49,4 +49,18 @@ static inline int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx, } #endif +/** + * mpam_register_requestor() - Register a requestor with the MPAM driver + * @partid_max: The maximum PARTID value the requestor can generate. + * @pmg_max: The maximum PMG value the requestor can generate. + * + * Registers a requestor with the MPAM driver to ensure the chosen system-wide + * minimum PARTID and PMG values will allow the requestors features to be used. + * + * Returns an error if the registration is too late, and a larger PARTID/PMG + * value has been advertised to user-space. In this case the requestor should + * not use its MPAM features. Returns 0 on success. + */ +int mpam_register_requestor(u16 partid_max, u8 pmg_max); + #endif /* __LINUX_ARM_MPAM_H */ |