From 3bd04fe7d807bbdcfe75b29ca82fae4e2d7dc524 Mon Sep 17 00:00:00 2001 From: James Morse Date: Wed, 19 Nov 2025 12:22:50 +0000 Subject: [PATCH] arm_mpam: Extend reset logic to allow devices to be reset any time cpuhp callbacks aren't the only time the MSC configuration may need to be reset. Resctrl has an API call to reset a class. If an MPAM error interrupt arrives it indicates the driver has misprogrammed an MSC. The safest thing to do is reset all the MSCs and disable MPAM. Add a helper to reset RIS via their class. Call this from mpam_disable(), which can be scheduled from the error interrupt handler. Signed-off-by: James Morse Reviewed-by: Jonathan Cameron Reviewed-by: Ben Horgan Reviewed-by: Gavin Shan Reviewed-by: Fenghua Yu Reviewed-by: Shaopeng Tan Tested-by: Fenghua Yu Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Carl Worth Tested-by: Gavin Shan Tested-by: Zeng Heng Tested-by: Hanjun Guo Signed-off-by: Ben Horgan Signed-off-by: Catalin Marinas --- drivers/resctrl/mpam_devices.c | 57 ++++++++++++++++++++++++++++++++-- 1 file changed, 54 insertions(+), 3 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 7941b093396ef..7943d174b3f46 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -808,15 +808,13 @@ static void mpam_reset_ris_partid(struct mpam_msc_ris *ris, u16 partid) /* * Called via smp_call_on_cpu() to prevent migration, while still being - * pre-emptible. + * pre-emptible. Caller must hold mpam_srcu. */ static int mpam_reset_ris(void *arg) { u16 partid, partid_max; struct mpam_msc_ris *ris = arg; - WARN_ON_ONCE(!srcu_read_lock_held((&mpam_srcu))); - if (ris->in_reset_state) return 0; @@ -1337,8 +1335,55 @@ static void mpam_enable_once(void) mpam_partid_max + 1, mpam_pmg_max + 1); } +static void mpam_reset_component_locked(struct mpam_component *comp) +{ + struct mpam_vmsc *vmsc; + + lockdep_assert_cpus_held(); + + guard(srcu)(&mpam_srcu); + list_for_each_entry_srcu(vmsc, &comp->vmsc, comp_list, + srcu_read_lock_held(&mpam_srcu)) { + struct mpam_msc *msc = vmsc->msc; + struct mpam_msc_ris *ris; + + list_for_each_entry_srcu(ris, &vmsc->ris, vmsc_list, + srcu_read_lock_held(&mpam_srcu)) { + if (!ris->in_reset_state) + mpam_touch_msc(msc, mpam_reset_ris, ris); + ris->in_reset_state = true; + } + } +} + +static void mpam_reset_class_locked(struct mpam_class *class) +{ + struct mpam_component *comp; + + lockdep_assert_cpus_held(); + + guard(srcu)(&mpam_srcu); + list_for_each_entry_srcu(comp, &class->components, class_list, + srcu_read_lock_held(&mpam_srcu)) + mpam_reset_component_locked(comp); +} + +static void mpam_reset_class(struct mpam_class *class) +{ + cpus_read_lock(); + mpam_reset_class_locked(class); + cpus_read_unlock(); +} + +/* + * Called in response to an error IRQ. + * All of MPAMs errors indicate a software bug, restore any modified + * controls to their reset values. + */ void mpam_disable(struct work_struct *ignored) { + int idx; + struct mpam_class *class; struct mpam_msc *msc, *tmp; mutex_lock(&mpam_cpuhp_state_lock); @@ -1348,6 +1393,12 @@ void mpam_disable(struct work_struct *ignored) } mutex_unlock(&mpam_cpuhp_state_lock); + idx = srcu_read_lock(&mpam_srcu); + list_for_each_entry_srcu(class, &mpam_classes, classes_list, + srcu_read_lock_held(&mpam_srcu)) + mpam_reset_class(class); + srcu_read_unlock(&mpam_srcu, idx); + mutex_lock(&mpam_list_lock); list_for_each_entry_safe(msc, tmp, &mpam_all_msc, all_msc_list) mpam_msc_destroy(msc); -- 2.47.3