Commit a9336ddf authored by Deb McLemore's avatar Deb McLemore Committed by Michael Ellerman
Browse files

powerpc/powernv: Add queue mechanism for early messages 



When issuing a BMC soft poweroff during IPL, the poweroff can be lost
so the machine would not poweroff.

This is because opal messages can be received before the opal-power
code registered its notifiers.

Fix it by buffering messages. If we receive a message and do not yet
have a handler for that type, store the message and replay when a
handler for that type is registered.

Signed-off-by: default avatarDeb McLemore <debmc@linux.vnet.ibm.com>
[mpe: Single unlock path in opal_message_notifier_register(), tweak
      comments/formatting and change log.]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1526868278-4204-1-git-send-email-debmc@linux.vnet.ibm.com
parent 29674a1c

arch/powerpc/platforms/powernv/opal.c

+84 −2
Original line number Diff line number Diff line
@@ -35,6 +35,16 @@ 


#include "powernv.h"



#define OPAL_MSG_QUEUE_MAX 16



struct opal_msg_node {

	struct list_head	list;

	struct opal_msg		msg;

};



static DEFINE_SPINLOCK(msg_list_lock);

static LIST_HEAD(msg_list);



/* /sys/firmware/opal */

struct kobject *opal_kobj;
@@ -50,6 +60,8 @@ struct mcheck_recoverable_range { 
	u64 recover_addr;

};



static int msg_list_size;



static struct mcheck_recoverable_range *mc_recoverable_range;

static int mc_recoverable_range_len;
@@ -237,6 +249,43 @@ static int __init opal_register_exception_handlers(void) 
}

machine_early_initcall(powernv, opal_register_exception_handlers);



static void queue_replay_msg(void *msg)

{

	struct opal_msg_node *msg_node;



	if (msg_list_size < OPAL_MSG_QUEUE_MAX) {

		msg_node = kzalloc(sizeof(*msg_node), GFP_ATOMIC);

		if (msg_node) {

			INIT_LIST_HEAD(&msg_node->list);

			memcpy(&msg_node->msg, msg, sizeof(struct opal_msg));

			list_add_tail(&msg_node->list, &msg_list);

			msg_list_size++;

		} else

			pr_warn_once("message queue no memory\n");



		if (msg_list_size >= OPAL_MSG_QUEUE_MAX)

			pr_warn_once("message queue full\n");

	}

}



static void dequeue_replay_msg(enum opal_msg_type msg_type)

{

	struct opal_msg_node *msg_node, *tmp;



	list_for_each_entry_safe(msg_node, tmp, &msg_list, list) {

		if (be32_to_cpu(msg_node->msg.msg_type) != msg_type)

			continue;



		atomic_notifier_call_chain(&opal_msg_notifier_head[msg_type],

					msg_type,

					&msg_node->msg);



		list_del(&msg_node->list);

		kfree(msg_node);

		msg_list_size--;

	}

}



/*

 * Opal message notifier based on message type. Allow subscribers to get

 * notified for specific messgae type.
@@ -244,14 +293,30 @@ machine_early_initcall(powernv, opal_register_exception_handlers); 
int opal_message_notifier_register(enum opal_msg_type msg_type,

					struct notifier_block *nb)

{

	int ret;

	unsigned long flags;



	if (!nb || msg_type >= OPAL_MSG_TYPE_MAX) {

		pr_warn("%s: Invalid arguments, msg_type:%d\n",

			__func__, msg_type);

		return -EINVAL;

	}



	return atomic_notifier_chain_register(

	spin_lock_irqsave(&msg_list_lock, flags);

	ret = atomic_notifier_chain_register(

		&opal_msg_notifier_head[msg_type], nb);



	/*

	 * If the registration succeeded, replay any queued messages that came

	 * in prior to the notifier chain registration. msg_list_lock held here

	 * to ensure they're delivered prior to any subsequent messages.

	 */

	if (ret == 0)

		dequeue_replay_msg(msg_type);



	spin_unlock_irqrestore(&msg_list_lock, flags);



	return ret;

}

EXPORT_SYMBOL_GPL(opal_message_notifier_register);
@@ -265,6 +330,23 @@ EXPORT_SYMBOL_GPL(opal_message_notifier_unregister); 


static void opal_message_do_notify(uint32_t msg_type, void *msg)

{

	unsigned long flags;

	bool queued = false;



	spin_lock_irqsave(&msg_list_lock, flags);

	if (opal_msg_notifier_head[msg_type].head == NULL) {

		/*

		 * Queue up the msg since no notifiers have registered

		 * yet for this msg_type.

		 */

		queue_replay_msg(msg);

		queued = true;

	}

	spin_unlock_irqrestore(&msg_list_lock, flags);



	if (queued)

		return;



	/* notify subscribers */

	atomic_notifier_call_chain(&opal_msg_notifier_head[msg_type],

					msg_type, msg);

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