Hi Jonathan,

On 7/30/20 8:54 PM, Jonathan Cameron wrote:

On Thu, 30 Jul 2020 11:45:29 +1000
Gavin Shan [off-list ref] wrote:

quoted

This splits struct sdei_event into two structs: sdei_event and
sdei_internal_event. The former one can be dereferenced from external
module like arm64/kvm when SDEI virtualization is supported. The later
one is used by the client driver only.

This also renames local variables from @event to @event_el if their
type is "struct sdei_internal_event" to make the variable name a bit
meaningful. Note that it's not applied to sdei_do_{local,cross}_call()
because CROSSCALL_INIT stops us doing this unless much more changes
are needed. I'm avoiding to do that.

Besides, @event is added as "struct sdei_event" to cache @event_el->event
if it's accessed for multiple times in the particular function to reduce
the code change size.

This shouldn't cause functional changes.

Signed-off-by: Gavin Shan <redacted>
---
v4: Rename variable @event to @event_el if it's internal event

Looks like a few cases were missed.

quoted

     Use @event to cache @event_el->event if it's used for multiple times

I'm not totally sure this splitting of the structure was worth the pain :(
(even though I suggested it :)
It perhaps makes things easier in the long run though.  Until we get the
user in place, it does look a bit over architected!

Yeah, more changes are introduced because of this. However, I do think
it's a good idea to hide these fields and prevent them being exposed
in long run. So I think the effort is still worthy.

I'm fine with it, but others may well not be!

Reviewed-by: Jonathan Cameron <redacted>

Thank you for your comments and time on this. I think you've finished
the review on all the patches :)

quoted

---
  drivers/firmware/arm_sdei.c | 160 ++++++++++++++++++++----------------
  include/linux/arm_sdei.h    |   6 ++
  2 files changed, 94 insertions(+), 72 deletions(-)

diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index 2678475940e6..f9827c096275 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c

@@ -44,16 +44,14 @@ static asmlinkage void (*sdei_firmware_call)(unsigned long function_id,
  /* entry point from firmware to arch asm code */
  static unsigned long sdei_entry_point;
  
-struct sdei_event {
+struct sdei_internal_event {
+	struct sdei_event	event;
+
  	/* These three are protected by the sdei_list_lock */
  	struct list_head	list;
  	bool			reregister;
  	bool			reenable;
  
-	u32			event_num;
-	u8			type;
-	u8			priority;
-
  	/* This pointer is handed to firmware as the event argument. */
  	union {
  		/* Shared events */

@@ -73,7 +71,7 @@ static LIST_HEAD(sdei_list);
  
  /* Private events are registered/enabled via IPI passing one of these */
  struct sdei_crosscall_args {
-	struct sdei_event *event;
+	struct sdei_internal_event *event;

Even though it is a bit painful should probably aim for consistent naming so
this and the other cases related to crosscall should be event_el;

Agree, I will put this into my TODO list and post a patch to address it
later. I don't want introduce more changes into this patch, considering
the change size.

quoted

  	atomic_t errors;
  	int first_error;
  };

@@ -86,7 +84,7 @@ struct sdei_crosscall_args {
  	} while (0)
  
  static inline int sdei_do_local_call(smp_call_func_t fn,
-				     struct sdei_event *event)
+				     struct sdei_internal_event *event)
  {
  	struct sdei_crosscall_args arg;
  

@@ -97,7 +95,7 @@ static inline int sdei_do_local_call(smp_call_func_t fn,
  }
  
  static inline int sdei_do_cross_call(smp_call_func_t fn,
-				     struct sdei_event *event)
+				     struct sdei_internal_event *event)
  {
  	struct sdei_crosscall_args arg;
  

@@ -162,16 +160,16 @@ static int invoke_sdei_fn(unsigned long function_id, unsigned long arg0,
  }
  NOKPROBE_SYMBOL(invoke_sdei_fn);
  
-static struct sdei_event *sdei_event_find(u32 event_num)
+static struct sdei_internal_event *sdei_event_find(u32 event_num)
  {
-	struct sdei_event *e, *found = NULL;
+	struct sdei_internal_event *event_el, *found = NULL;
  
  	lockdep_assert_held(&sdei_events_lock);
  
  	spin_lock(&sdei_list_lock);
-	list_for_each_entry(e, &sdei_list, list) {
-		if (e->event_num == event_num) {
-			found = e;
+	list_for_each_entry(event_el, &sdei_list, list) {
+		if (event_el->event.event_num == event_num) {
+			found = event_el;
  			break;
  		}
  	}

@@ -193,24 +191,26 @@ static int sdei_api_event_get_info(u32 event, u32 info, u64 *result)
  			      0, 0, result);
  }
  
-static struct sdei_event *sdei_event_create(u32 event_num,
-					    sdei_event_callback *cb,
-					    void *cb_arg)
+static struct sdei_internal_event *sdei_event_create(u32 event_num,
+						     sdei_event_callback *cb,
+						     void *cb_arg)
  {
  	int err;
  	u64 result;
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;
  	struct sdei_registered_event *reg;
  
  	lockdep_assert_held(&sdei_events_lock);
  
-	event = kzalloc(sizeof(*event), GFP_KERNEL);
-	if (!event) {
+	event_el = kzalloc(sizeof(*event_el), GFP_KERNEL);
+	if (!event_el) {
  		err = -ENOMEM;
  		goto fail;
  	}
  
-	INIT_LIST_HEAD(&event->list);
+	event = &event_el->event;
+	INIT_LIST_HEAD(&event_el->list);
  	event->event_num = event_num;
  
  	err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY,

@@ -237,7 +237,7 @@ static struct sdei_event *sdei_event_create(u32 event_num,
  
  		reg->callback = cb;
  		reg->callback_arg = cb_arg;
-		event->registered = reg;
+		event_el->registered = reg;
  	} else {
  		int cpu;
  		struct sdei_registered_event __percpu *regs;

@@ -257,39 +257,39 @@ static struct sdei_event *sdei_event_create(u32 event_num,
  			reg->callback_arg = cb_arg;
  		}
  
-		event->private_registered = regs;
+		event_el->private_registered = regs;
  	}
  
  	spin_lock(&sdei_list_lock);
-	list_add(&event->list, &sdei_list);
+	list_add(&event_el->list, &sdei_list);
  	spin_unlock(&sdei_list_lock);
  
-	return event;
+	return event_el;
  
  fail:
-	kfree(event);
+	kfree(event_el);
  	return ERR_PTR(err);
  }
  
-static void sdei_event_destroy_llocked(struct sdei_event *event)
+static void sdei_event_destroy_llocked(struct sdei_internal_event *event_el)
  {
  	lockdep_assert_held(&sdei_events_lock);
  	lockdep_assert_held(&sdei_list_lock);
  
-	list_del(&event->list);
+	list_del(&event_el->list);
  
-	if (event->type == SDEI_EVENT_TYPE_SHARED)
-		kfree(event->registered);
+	if (event_el->event.type == SDEI_EVENT_TYPE_SHARED)
+		kfree(event_el->registered);
  	else
-		free_percpu(event->private_registered);
+		free_percpu(event_el->private_registered);
  
-	kfree(event);
+	kfree(event_el);
  }
  
-static void sdei_event_destroy(struct sdei_event *event)
+static void sdei_event_destroy(struct sdei_internal_event *event_el)
  {
  	spin_lock(&sdei_list_lock);
-	sdei_event_destroy_llocked(event);
+	sdei_event_destroy_llocked(event_el);
  	spin_unlock(&sdei_list_lock);
  }
  

@@ -392,7 +392,7 @@ static void _local_event_enable(void *data)
  
  	WARN_ON_ONCE(preemptible());
  
-	err = sdei_api_event_enable(arg->event->event_num);
+	err = sdei_api_event_enable(arg->event->event.event_num);
  
  	sdei_cross_call_return(arg, err);
  }

@@ -400,25 +400,27 @@ static void _local_event_enable(void *data)
  int sdei_event_enable(u32 event_num)
  {
  	int err = -EINVAL;
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;
  
  	mutex_lock(&sdei_events_lock);
-	event = sdei_event_find(event_num);
-	if (!event) {
+	event_el = sdei_event_find(event_num);
+	if (!event_el) {
  		mutex_unlock(&sdei_events_lock);
  		return -ENOENT;
  	}
  
  
  	cpus_read_lock();
+	event = &event_el->event;
  	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);
+		err = sdei_do_cross_call(_local_event_enable, event_el);
  
  	if (!err) {
  		spin_lock(&sdei_list_lock);
-		event->reenable = true;
+		event_el->reenable = true;
  		spin_unlock(&sdei_list_lock);
  	}
  	cpus_read_unlock();

@@ -438,7 +440,7 @@ static void _ipi_event_disable(void *data)
  	int err;
  	struct sdei_crosscall_args *arg = data;
  
-	err = sdei_api_event_disable(arg->event->event_num);
+	err = sdei_api_event_disable(arg->event->event.event_num);
  
  	sdei_cross_call_return(arg, err);
  }

@@ -446,23 +448,25 @@ static void _ipi_event_disable(void *data)
  int sdei_event_disable(u32 event_num)
  {
  	int err = -EINVAL;
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;
  
  	mutex_lock(&sdei_events_lock);
-	event = sdei_event_find(event_num);
-	if (!event) {
+	event_el = sdei_event_find(event_num);
+	if (!event_el) {
  		mutex_unlock(&sdei_events_lock);
  		return -ENOENT;
  	}
  
  	spin_lock(&sdei_list_lock);
-	event->reenable = false;
+	event_el->reenable = false;
  	spin_unlock(&sdei_list_lock);
  
+	event = &event_el->event;
  	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);
+		err = sdei_do_cross_call(_ipi_event_disable, event_el);
  	mutex_unlock(&sdei_events_lock);
  
  	return err;

@@ -482,7 +486,7 @@ static void _local_event_unregister(void *data)
  
  	WARN_ON_ONCE(preemptible());
  
-	err = sdei_api_event_unregister(arg->event->event_num);
+	err = sdei_api_event_unregister(arg->event->event.event_num);
  
  	sdei_cross_call_return(arg, err);
  }

@@ -490,32 +494,34 @@ static void _local_event_unregister(void *data)
  int sdei_event_unregister(u32 event_num)
  {
  	int err;
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;
  
  	WARN_ON(in_nmi());
  
  	mutex_lock(&sdei_events_lock);
-	event = sdei_event_find(event_num);
-	if (!event) {
+	event_el = sdei_event_find(event_num);
+	if (!event_el) {
  		pr_warn("Event %u not registered\n", event_num);
  		err = -ENOENT;
  		goto unlock;
  	}
  
  	spin_lock(&sdei_list_lock);
-	event->reregister = false;
-	event->reenable = false;
+	event_el->reregister = false;
+	event_el->reenable = false;
  	spin_unlock(&sdei_list_lock);
  
+	event = &event_el->event;
  	if (event->type == SDEI_EVENT_TYPE_SHARED)
  		err = sdei_api_event_unregister(event->event_num);
  	else
-		err = sdei_do_cross_call(_local_event_unregister, event);
+		err = sdei_do_cross_call(_local_event_unregister, event_el);
  
  	if (err)
  		goto unlock;
  
-	sdei_event_destroy(event);
+	sdei_event_destroy(event_el);
  unlock:
  	mutex_unlock(&sdei_events_lock);
  

@@ -529,11 +535,13 @@ int sdei_event_unregister(u32 event_num)
  static int sdei_unregister_shared(void)
  {
  	int err = 0;
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;
  
  	mutex_lock(&sdei_events_lock);
  	spin_lock(&sdei_list_lock);
-	list_for_each_entry(event, &sdei_list, list) {
+	list_for_each_entry(event_el, &sdei_list, list) {
+		event = &event_el->event;
  		if (event->type != SDEI_EVENT_TYPE_SHARED)
  			continue;
  

@@ -565,8 +573,8 @@ static void _local_event_register(void *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);
+	err = sdei_api_event_register(arg->event->event.event_num,
+				      sdei_entry_point, reg, 0, 0);
  
  	sdei_cross_call_return(arg, err);
  }

@@ -574,6 +582,7 @@ static void _local_event_register(void *data)
  int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
  {
  	int err;
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;
  
  	WARN_ON(in_nmi());

@@ -585,33 +594,34 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
  		goto unlock;
  	}
  
-	event = sdei_event_create(event_num, cb, arg);
-	if (IS_ERR(event)) {
-		err = PTR_ERR(event);
+	event_el = sdei_event_create(event_num, cb, arg);
+	if (IS_ERR(event_el)) {
+		err = PTR_ERR(event_el);
  		pr_warn("Failed to create event %u: %d\n", event_num, err);
  		goto unlock;
  	}
  
  	cpus_read_lock();
+	event = &event_el->event;
  	if (event->type == SDEI_EVENT_TYPE_SHARED) {
  		err = sdei_api_event_register(event->event_num,
  					      sdei_entry_point,
-					      event->registered,
+					      event_el->registered,
  					      SDEI_EVENT_REGISTER_RM_ANY, 0);
  	} else {
-		err = sdei_do_cross_call(_local_event_register, event);
+		err = sdei_do_cross_call(_local_event_register, event_el);
  		if (err)
-			sdei_do_cross_call(_local_event_unregister, event);
+			sdei_do_cross_call(_local_event_unregister, event_el);
  	}
  
  	if (err) {
-		sdei_event_destroy(event);
+		sdei_event_destroy(event_el);
  		pr_warn("Failed to register event %u: %d\n", event_num, err);
  		goto cpu_unlock;
  	}
  
  	spin_lock(&sdei_list_lock);
-	event->reregister = true;
+	event_el->reregister = true;
  	spin_unlock(&sdei_list_lock);
  cpu_unlock:
  	cpus_read_unlock();

@@ -623,27 +633,29 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
  static int sdei_reregister_shared(void)
  {
  	int err = 0;
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;

Could reduce the scope by moving this in the loop.  Not that important though.

Yeah, but it's fine not to move it.

quoted

  
  	mutex_lock(&sdei_events_lock);
  	spin_lock(&sdei_list_lock);
-	list_for_each_entry(event, &sdei_list, list) {
+	list_for_each_entry(event_el, &sdei_list, list) {
+		event = &event_el->event;
  		if (event->type != SDEI_EVENT_TYPE_SHARED)
  			continue;
  
-		if (event->reregister) {
+		if (event_el->reregister) {
  			err = sdei_api_event_register(event->event_num,
-					sdei_entry_point, event->registered,
+					sdei_entry_point, event_el->registered,
  					SDEI_EVENT_REGISTER_RM_ANY, 0);
  			if (err) {
-				sdei_event_destroy_llocked(event);
+				sdei_event_destroy_llocked(event_el);
  				pr_err("Failed to re-register event %u\n",
  				       event->event_num);
  				break;
  			}
  		}
  
-		if (event->reenable) {
+		if (event_el->reenable) {
  			err = sdei_api_event_enable(event->event_num);
  			if (err) {
  				pr_err("Failed to re-enable event %u\n",

@@ -660,16 +672,18 @@ static int sdei_reregister_shared(void)
  
  static int sdei_cpuhp_down(unsigned int cpu)
  {
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;
  	int err;
  
  	/* un-register private events */
  	spin_lock(&sdei_list_lock);
-	list_for_each_entry(event, &sdei_list, list) {
+	list_for_each_entry(event_el, &sdei_list, list) {
+		event = &event_el->event;
  		if (event->type == SDEI_EVENT_TYPE_SHARED)
  			continue;
  
-		err = sdei_do_local_call(_local_event_unregister, event);
+		err = sdei_do_local_call(_local_event_unregister, event_el);
  		if (err) {
  			pr_err("Failed to unregister event %u: %d\n",
  			       event->event_num, err);

@@ -682,25 +696,27 @@ static int sdei_cpuhp_down(unsigned int cpu)
  
  static int sdei_cpuhp_up(unsigned int cpu)
  {
+	struct sdei_internal_event *event_el;
  	struct sdei_event *event;
  	int err;
  
  	/* re-register/enable private events */
  	spin_lock(&sdei_list_lock);
-	list_for_each_entry(event, &sdei_list, list) {
+	list_for_each_entry(event_el, &sdei_list, list) {
+		event = &event_el->event;
  		if (event->type == SDEI_EVENT_TYPE_SHARED)
  			continue;
  
-		if (event->reregister) {
-			err = sdei_do_local_call(_local_event_register, event);
+		if (event_el->reregister) {
+			err = sdei_do_local_call(_local_event_register, event_el);
  			if (err) {
  				pr_err("Failed to re-register event %u: %d\n",
  				       event->event_num, err);
  			}
  		}
  
-		if (event->reenable) {
-			err = sdei_do_local_call(_local_event_enable, event);
+		if (event_el->reenable) {
+			err = sdei_do_local_call(_local_event_enable, event_el);
  			if (err) {
  				pr_err("Failed to re-enable event %u: %d\n",
  				       event->event_num, err);

diff --git a/include/linux/arm_sdei.h b/include/linux/arm_sdei.h
index 0a241c5c911d..d2464a18b6ff 100644
--- a/include/linux/arm_sdei.h
+++ b/include/linux/arm_sdei.h

@@ -22,6 +22,12 @@
   */
  typedef int (sdei_event_callback)(u32 event, struct pt_regs *regs, void *arg);
  
+struct sdei_event {
+	u32			event_num;
+	u8			type;
+	u8			priority;
+};
+
  /*
   * Register your callback to claim an event. The event must be described
   * by firmware.

Thanks,
Gavin
  


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