add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/arch/powerpc/kernel/eeh_event.c
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@@ -1,17 +1,5 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /*
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License as published by
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- * the Free Software Foundation; either version 2 of the License, or
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- * (at your option) any later version.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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- *
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- * You should have received a copy of the GNU General Public License
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- * along with this program; if not, write to the Free Software
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- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
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  *
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  * Copyright (c) 2005 Linas Vepstas <linas@linas.org>
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  */
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@@ -35,7 +23,7 @@
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  */
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 static DEFINE_SPINLOCK(eeh_eventlist_lock);
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-static struct semaphore eeh_eventlist_sem;
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+static DECLARE_COMPLETION(eeh_eventlist_event);
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 static LIST_HEAD(eeh_eventlist);
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 /**
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@@ -52,10 +40,9 @@
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 {
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 	unsigned long flags;
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 	struct eeh_event *event;
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-	struct eeh_pe *pe;
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 	while (!kthread_should_stop()) {
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-		if (down_interruptible(&eeh_eventlist_sem))
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+		if (wait_for_completion_interruptible(&eeh_eventlist_event))
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 			break;
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 		/* Fetch EEH event from the queue */
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@@ -71,19 +58,10 @@
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 			continue;
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 		/* We might have event without binding PE */
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-		pe = event->pe;
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-		if (pe) {
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-			if (pe->type & EEH_PE_PHB)
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-				pr_info("EEH: Detected error on PHB#%x\n",
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-					 pe->phb->global_number);
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-			else
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-				pr_info("EEH: Detected PCI bus error on "
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-					"PHB#%x-PE#%x\n",
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-					pe->phb->global_number, pe->addr);
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-			eeh_handle_normal_event(pe);
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-		} else {
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+		if (event->pe)
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+			eeh_handle_normal_event(event->pe);
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+		else
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 			eeh_handle_special_event();
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-		}
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 		kfree(event);
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 	}
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@@ -101,9 +79,6 @@
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 {
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 	struct task_struct *t;
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 	int ret = 0;
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-
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-	/* Initialize semaphore */
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-	sema_init(&eeh_eventlist_sem, 0);
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 	t = kthread_run(eeh_event_handler, NULL, "eehd");
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 	if (IS_ERR(t)) {
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@@ -124,7 +99,7 @@
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  * the actual event will be delivered in a normal context
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  * (from a workqueue).
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  */
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-int eeh_send_failure_event(struct eeh_pe *pe)
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+int __eeh_send_failure_event(struct eeh_pe *pe)
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 {
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 	unsigned long flags;
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 	struct eeh_event *event;
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@@ -136,17 +111,49 @@
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 	}
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 	event->pe = pe;
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+	/*
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+	 * Mark the PE as recovering before inserting it in the queue.
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+	 * This prevents the PE from being free()ed by a hotplug driver
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+	 * while the PE is sitting in the event queue.
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+	 */
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+	if (pe) {
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+#ifdef CONFIG_STACKTRACE
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+		/*
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+		 * Save the current stack trace so we can dump it from the
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+		 * event handler thread.
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+		 */
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+		pe->trace_entries = stack_trace_save(pe->stack_trace,
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+					 ARRAY_SIZE(pe->stack_trace), 0);
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+#endif /* CONFIG_STACKTRACE */
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+
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+		eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
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+	}
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+
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 	/* We may or may not be called in an interrupt context */
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 	spin_lock_irqsave(&eeh_eventlist_lock, flags);
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 	list_add(&event->list, &eeh_eventlist);
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 	spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
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 	/* For EEH deamon to knick in */
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-	up(&eeh_eventlist_sem);
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+	complete(&eeh_eventlist_event);
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 	return 0;
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 }
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+int eeh_send_failure_event(struct eeh_pe *pe)
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+{
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+	/*
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+	 * If we've manually supressed recovery events via debugfs
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+	 * then just drop it on the floor.
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+	 */
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+	if (eeh_debugfs_no_recover) {
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+		pr_err("EEH: Event dropped due to no_recover setting\n");
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+		return 0;
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+	}
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+
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+	return __eeh_send_failure_event(pe);
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+}
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+
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 /**
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  * eeh_remove_event - Remove EEH event from the queue
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  * @pe: Event binding to the PE