1 files changed, 57 insertions, 38 deletions

diff --git a/arch/powerpc/kernel/eeh_event.c b/arch/powerpc/kernel/eeh_event.c
index d27c5afc90ae..c23a454af08a 100644
--- a/arch/powerpc/kernel/eeh_event.c
+++ b/arch/powerpc/kernel/eeh_event.c
@@ -1,17 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  *
  * Copyright (c) 2005 Linas Vepstas <linas@linas.org>
  */
@@ -35,8 +23,8 @@
  */
 
 static DEFINE_SPINLOCK(eeh_eventlist_lock);
-static struct semaphore eeh_eventlist_sem;
-LIST_HEAD(eeh_eventlist);
+static DECLARE_COMPLETION(eeh_eventlist_event);
+static LIST_HEAD(eeh_eventlist);
 
 /**
  * eeh_event_handler - Dispatch EEH events.
@@ -52,10 +40,9 @@ static int eeh_event_handler(void * dummy)
 {
 	unsigned long flags;
 	struct eeh_event *event;
-	struct eeh_pe *pe;
 
 	while (!kthread_should_stop()) {
-		if (down_interruptible(&eeh_eventlist_sem))
+		if (wait_for_completion_interruptible(&eeh_eventlist_event))
 			break;
 
 		/* Fetch EEH event from the queue */
@@ -71,16 +58,10 @@ static int eeh_event_handler(void * dummy)
 			continue;
 
 		/* We might have event without binding PE */
-		pe = event->pe;
-		if (pe) {
-			eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
-			pr_info("EEH: Detected PCI bus error on PHB#%d-PE#%x\n",
-				 pe->phb->global_number, pe->addr);
-			eeh_handle_event(pe);
-			eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
-		} else {
-			eeh_handle_event(NULL);
-		}
+		if (event->pe)
+			eeh_handle_normal_event(event->pe);
+		else
+			eeh_handle_special_event();
 
 		kfree(event);
 	}
@@ -99,9 +80,6 @@ int eeh_event_init(void)
 	struct task_struct *t;
 	int ret = 0;
 
-	/* Initialize semaphore */
-	sema_init(&eeh_eventlist_sem, 0);
-
 	t = kthread_run(eeh_event_handler, NULL, "eehd");
 	if (IS_ERR(t)) {
 		ret = PTR_ERR(t);
@@ -121,7 +99,7 @@ int eeh_event_init(void)
  * the actual event will be delivered in a normal context
  * (from a workqueue).
  */
-int eeh_send_failure_event(struct eeh_pe *pe)
+int __eeh_send_failure_event(struct eeh_pe *pe)
 {
 	unsigned long flags;
 	struct eeh_event *event;
@@ -133,38 +111,79 @@ int eeh_send_failure_event(struct eeh_pe *pe)
 	}
 	event->pe = pe;
 
+	/*
+	 * Mark the PE as recovering before inserting it in the queue.
+	 * This prevents the PE from being free()ed by a hotplug driver
+	 * while the PE is sitting in the event queue.
+	 */
+	if (pe) {
+#ifdef CONFIG_STACKTRACE
+		/*
+		 * Save the current stack trace so we can dump it from the
+		 * event handler thread.
+		 */
+		pe->trace_entries = stack_trace_save(pe->stack_trace,
+					 ARRAY_SIZE(pe->stack_trace), 0);
+#endif /* CONFIG_STACKTRACE */
+
+		eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
+	}
+
 	/* We may or may not be called in an interrupt context */
 	spin_lock_irqsave(&eeh_eventlist_lock, flags);
 	list_add(&event->list, &eeh_eventlist);
 	spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
 
 	/* For EEH deamon to knick in */
-	up(&eeh_eventlist_sem);
+	complete(&eeh_eventlist_event);
 
 	return 0;
 }
 
+int eeh_send_failure_event(struct eeh_pe *pe)
+{
+	/*
+	 * If we've manually suppressed recovery events via debugfs
+	 * then just drop it on the floor.
+	 */
+	if (eeh_debugfs_no_recover) {
+		pr_err("EEH: Event dropped due to no_recover setting\n");
+		return 0;
+	}
+
+	return __eeh_send_failure_event(pe);
+}
+
 /**
  * eeh_remove_event - Remove EEH event from the queue
  * @pe: Event binding to the PE
+ * @force: Event will be removed unconditionally
  *
  * On PowerNV platform, we might have subsequent coming events
  * is part of the former one. For that case, those subsequent
  * coming events are totally duplicated and unnecessary, thus
  * they should be removed.
  */
-void eeh_remove_event(struct eeh_pe *pe)
+void eeh_remove_event(struct eeh_pe *pe, bool force)
 {
 	unsigned long flags;
 	struct eeh_event *event, *tmp;
 
+	/*
+	 * If we have NULL PE passed in, we have dead IOC
+	 * or we're sure we can report all existing errors
+	 * by the caller.
+	 *
+	 * With "force", the event with associated PE that
+	 * have been isolated, the event won't be removed
+	 * to avoid event lost.
+	 */
 	spin_lock_irqsave(&eeh_eventlist_lock, flags);
 	list_for_each_entry_safe(event, tmp, &eeh_eventlist, list) {
-		/*
-		 * If we don't have valid PE passed in, that means
-		 * we already have event corresponding to dead IOC
-		 * and all events should be purged.
-		 */
+		if (!force && event->pe &&
+		    (event->pe->state & EEH_PE_ISOLATED))
+			continue;
+
 		if (!pe) {
 			list_del(&event->list);
 			kfree(event);