Commit 3bd04fe7 authored by James Morse's avatar James Morse Committed by Catalin Marinas
Browse files

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: default avatarJames Morse <james.morse@arm.com>
Reviewed-by: default avatarJonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: default avatarBen Horgan <ben.horgan@arm.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Reviewed-by: default avatarFenghua Yu <fenghuay@nvidia.com>
Reviewed-by: default avatarShaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: default avatarFenghua Yu <fenghuay@nvidia.com>
Tested-by: default avatarShaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: default avatarPeter Newman <peternewman@google.com>
Tested-by: default avatarCarl Worth <carl@os.amperecomputing.com>
Tested-by: default avatarGavin Shan <gshan@redhat.com>
Tested-by: default avatarZeng Heng <zengheng4@huawei.com>
Tested-by: default avatarHanjun Guo <guohanjun@huawei.com>
Signed-off-by: default avatarBen Horgan <ben.horgan@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 475228d1

drivers/resctrl/mpam_devices.c

+54 −3
Original line number Diff line number Diff line
@@ -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);