Commit f92b5462 authored by James Morse's avatar James Morse Committed by Catalin Marinas
Browse files

firmware: arm_sdei: add support for CPU private events 



Private SDE events are per-cpu, and need to be registered and enabled
on each CPU.

Hide this detail from the caller by adapting our {,un}register and
{en,dis}able calls to send an IPI to each CPU if the event is private.

CPU private events are unregistered when the CPU is powered-off, and
re-registered when the CPU is brought back online. This saves bringing
secondary cores back online to call private_reset() on shutdown, kexec
and resume from hibernate.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent da351827

drivers/firmware/arm_sdei.c

+193 −13
Original line number Diff line number Diff line
@@ -5,9 +5,11 @@ 
#include <linux/acpi.h>

#include <linux/arm_sdei.h>

#include <linux/arm-smccc.h>

#include <linux/atomic.h>

#include <linux/bitops.h>

#include <linux/compiler.h>

#include <linux/cpuhotplug.h>

#include <linux/cpu.h>

#include <linux/cpu_pm.h>

#include <linux/errno.h>

#include <linux/hardirq.h>
@@ -52,7 +54,13 @@ struct sdei_event { 
	u8			priority;



	/* This pointer is handed to firmware as the event argument. */

	union {

		/* Shared events */

		struct sdei_registered_event *registered;



		/* CPU private events */

		struct sdei_registered_event __percpu *private_registered;

	};

};



/* Take the mutex for any API call or modification. Take the mutex first. */
@@ -62,6 +70,34 @@ static DEFINE_MUTEX(sdei_events_lock); 
static DEFINE_SPINLOCK(sdei_list_lock);

static LIST_HEAD(sdei_list);



/* Private events are registered/enabled via IPI passing one of these */

struct sdei_crosscall_args {

	struct sdei_event *event;

	atomic_t errors;

	int first_error;

};



#define CROSSCALL_INIT(arg, event)	(arg.event = event, \

					 arg.first_error = 0, \

					 atomic_set(&arg.errors, 0))



static inline int sdei_do_cross_call(void *fn, struct sdei_event * event)

{

	struct sdei_crosscall_args arg;



	CROSSCALL_INIT(arg, event);

	on_each_cpu(fn, &arg, true);



	return arg.first_error;

}



static inline void

sdei_cross_call_return(struct sdei_crosscall_args *arg, int err)

{

	if (err && (atomic_inc_return(&arg->errors) == 1))

		arg->first_error = err;

}



static int sdei_to_linux_errno(unsigned long sdei_err)

{

	switch (sdei_err) {
@@ -207,6 +243,26 @@ static struct sdei_event *sdei_event_create(u32 event_num, 
		reg->callback = cb;

		reg->callback_arg = cb_arg;

		event->registered = reg;

	} else {

		int cpu;

		struct sdei_registered_event __percpu *regs;



		regs = alloc_percpu(struct sdei_registered_event);

		if (!regs) {

			kfree(event);

			return ERR_PTR(-ENOMEM);

		}



		for_each_possible_cpu(cpu) {

			reg = per_cpu_ptr(regs, cpu);



			reg->event_num = event->event_num;

			reg->priority = event->priority;

			reg->callback = cb;

			reg->callback_arg = cb_arg;

		}



		event->private_registered = regs;

	}



	if (sdei_event_find(event_num)) {
@@ -232,6 +288,8 @@ static void sdei_event_destroy(struct sdei_event *event) 


	if (event->type == SDEI_EVENT_TYPE_SHARED)

		kfree(event->registered);

	else

		free_percpu(event->private_registered);



	kfree(event);

}
@@ -262,11 +320,6 @@ static void _ipi_mask_cpu(void *ignored) 
	sdei_mask_local_cpu();

}



static int sdei_cpuhp_down(unsigned int ignored)

{

	return sdei_mask_local_cpu();

}



int sdei_unmask_local_cpu(void)

{

	int err;
@@ -288,11 +341,6 @@ static void _ipi_unmask_cpu(void *ignored) 
	sdei_unmask_local_cpu();

}



static int sdei_cpuhp_up(unsigned int ignored)

{

	return sdei_unmask_local_cpu();

}



static void _ipi_private_reset(void *ignored)

{

	int err;
@@ -337,6 +385,19 @@ static int sdei_api_event_enable(u32 event_num) 
			      0, NULL);

}



/* Called directly by the hotplug callbacks */

static void _local_event_enable(void *data)

{

	int err;

	struct sdei_crosscall_args *arg = data;



	WARN_ON_ONCE(preemptible());



	err = sdei_api_event_enable(arg->event->event_num);



	sdei_cross_call_return(arg, err);

}



int sdei_event_enable(u32 event_num)

{

	int err = -EINVAL;
@@ -355,6 +416,8 @@ int sdei_event_enable(u32 event_num) 


	if (event->type == SDEI_EVENT_TYPE_SHARED)

		err = sdei_api_event_enable(event->event_num);

	else

		err = sdei_do_cross_call(_local_event_enable, event);

	mutex_unlock(&sdei_events_lock);



	return err;
@@ -367,6 +430,16 @@ static int sdei_api_event_disable(u32 event_num) 
			      0, 0, NULL);

}



static void _ipi_event_disable(void *data)

{

	int err;

	struct sdei_crosscall_args *arg = data;



	err = sdei_api_event_disable(arg->event->event_num);



	sdei_cross_call_return(arg, err);

}



int sdei_event_disable(u32 event_num)

{

	int err = -EINVAL;
@@ -385,6 +458,8 @@ int sdei_event_disable(u32 event_num) 


	if (event->type == SDEI_EVENT_TYPE_SHARED)

		err = sdei_api_event_disable(event->event_num);

	else

		err = sdei_do_cross_call(_ipi_event_disable, event);

	mutex_unlock(&sdei_events_lock);



	return err;
@@ -397,6 +472,19 @@ static int sdei_api_event_unregister(u32 event_num) 
			      0, 0, 0, NULL);

}



/* Called directly by the hotplug callbacks */

static void _local_event_unregister(void *data)

{

	int err;

	struct sdei_crosscall_args *arg = data;



	WARN_ON_ONCE(preemptible());



	err = sdei_api_event_unregister(arg->event->event_num);



	sdei_cross_call_return(arg, err);

}



static int _sdei_event_unregister(struct sdei_event *event)

{

	lockdep_assert_held(&sdei_events_lock);
@@ -409,7 +497,7 @@ static int _sdei_event_unregister(struct sdei_event *event) 
	if (event->type == SDEI_EVENT_TYPE_SHARED)

		return sdei_api_event_unregister(event->event_num);



	return -EINVAL;

	return sdei_do_cross_call(_local_event_unregister, event);

}



int sdei_event_unregister(u32 event_num)
@@ -473,17 +561,50 @@ static int sdei_api_event_register(u32 event_num, unsigned long entry_point, 
			      flags, affinity, NULL);

}



/* Called directly by the hotplug callbacks */

static void _local_event_register(void *data)

{

	int err;

	struct sdei_registered_event *reg;

	struct sdei_crosscall_args *arg = data;



	WARN_ON(preemptible());



	reg = per_cpu_ptr(arg->event->private_registered, smp_processor_id());

	err = sdei_api_event_register(arg->event->event_num, sdei_entry_point,

				      reg, 0, 0);



	sdei_cross_call_return(arg, err);

}



static int _sdei_event_register(struct sdei_event *event)

{

	int err;



	lockdep_assert_held(&sdei_events_lock);



	spin_lock(&sdei_list_lock);

	event->reregister = true;

	spin_unlock(&sdei_list_lock);



	if (event->type == SDEI_EVENT_TYPE_SHARED)

		return sdei_api_event_register(event->event_num,

					       sdei_entry_point,

					       event->registered,

					       SDEI_EVENT_REGISTER_RM_ANY, 0);



	return -EINVAL;



	err = sdei_do_cross_call(_local_event_register, event);

	if (err) {

		spin_lock(&sdei_list_lock);

		event->reregister = false;

		event->reenable = false;

		spin_unlock(&sdei_list_lock);



		sdei_do_cross_call(_local_event_unregister, event);

	}



	return err;

}



int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
@@ -538,6 +659,8 @@ static int sdei_reregister_event(struct sdei_event *event) 
	if (event->reenable) {

		if (event->type == SDEI_EVENT_TYPE_SHARED)

			err = sdei_api_event_enable(event->event_num);

		else

			err = sdei_do_cross_call(_local_event_enable, event);

	}



	if (err)
@@ -569,6 +692,62 @@ static int sdei_reregister_shared(void) 
	return err;

}



static int sdei_cpuhp_down(unsigned int cpu)

{

	struct sdei_event *event;

	struct sdei_crosscall_args arg;



	/* un-register private events */

	spin_lock(&sdei_list_lock);

	list_for_each_entry(event, &sdei_list, list) {

		if (event->type == SDEI_EVENT_TYPE_SHARED)

			continue;



		CROSSCALL_INIT(arg, event);

		/* call the cross-call function locally... */

		_local_event_unregister(&arg);

		if (arg.first_error)

			pr_err("Failed to unregister event %u: %d\n",

			       event->event_num, arg.first_error);

	}

	spin_unlock(&sdei_list_lock);



	return sdei_mask_local_cpu();

}



static int sdei_cpuhp_up(unsigned int cpu)

{

	struct sdei_event *event;

	struct sdei_crosscall_args arg;



	/* re-register/enable private events */

	spin_lock(&sdei_list_lock);

	list_for_each_entry(event, &sdei_list, list) {

		if (event->type == SDEI_EVENT_TYPE_SHARED)

			continue;



		if (event->reregister) {

			CROSSCALL_INIT(arg, event);

			/* call the cross-call function locally... */

			_local_event_register(&arg);

			if (arg.first_error)

				pr_err("Failed to re-register event %u: %d\n",

				       event->event_num, arg.first_error);

		}



		if (event->reenable) {

			CROSSCALL_INIT(arg, event);

			_local_event_enable(&arg);

			if (arg.first_error)

				pr_err("Failed to re-enable event %u: %d\n",

				       event->event_num, arg.first_error);

		}

	}

	spin_unlock(&sdei_list_lock);



	return sdei_unmask_local_cpu();

}



/* When entering idle, mask/unmask events for this cpu */

static int sdei_pm_notifier(struct notifier_block *nb, unsigned long action,

			    void *data)
@@ -622,6 +801,7 @@ static int sdei_device_freeze(struct device *dev) 
{

	int err;



	/* unregister private events */

	cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING);



	err = sdei_unregister_shared();

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