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-rw-r--r--arch/powerpc/kernel/eeh_event.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/eeh_event.c b/arch/powerpc/kernel/eeh_event.c
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index 0000000000..c23a454af0
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+++ b/arch/powerpc/kernel/eeh_event.c
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Copyright (c) 2005 Linas Vepstas <linas@linas.org>
+ */
+
+#include <linux/delay.h>
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/semaphore.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/kthread.h>
+#include <asm/eeh_event.h>
+#include <asm/ppc-pci.h>
+
+/** Overview:
+ * EEH error states may be detected within exception handlers;
+ * however, the recovery processing needs to occur asynchronously
+ * in a normal kernel context and not an interrupt context.
+ * This pair of routines creates an event and queues it onto a
+ * work-queue, where a worker thread can drive recovery.
+ */
+
+static DEFINE_SPINLOCK(eeh_eventlist_lock);
+static DECLARE_COMPLETION(eeh_eventlist_event);
+static LIST_HEAD(eeh_eventlist);
+
+/**
+ * eeh_event_handler - Dispatch EEH events.
+ * @dummy - unused
+ *
+ * The detection of a frozen slot can occur inside an interrupt,
+ * where it can be hard to do anything about it. The goal of this
+ * routine is to pull these detection events out of the context
+ * of the interrupt handler, and re-dispatch them for processing
+ * at a later time in a normal context.
+ */
+static int eeh_event_handler(void * dummy)
+{
+ unsigned long flags;
+ struct eeh_event *event;
+
+ while (!kthread_should_stop()) {
+ if (wait_for_completion_interruptible(&eeh_eventlist_event))
+ break;
+
+ /* Fetch EEH event from the queue */
+ spin_lock_irqsave(&eeh_eventlist_lock, flags);
+ event = NULL;
+ if (!list_empty(&eeh_eventlist)) {
+ event = list_entry(eeh_eventlist.next,
+ struct eeh_event, list);
+ list_del(&event->list);
+ }
+ spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
+ if (!event)
+ continue;
+
+ /* We might have event without binding PE */
+ if (event->pe)
+ eeh_handle_normal_event(event->pe);
+ else
+ eeh_handle_special_event();
+
+ kfree(event);
+ }
+
+ return 0;
+}
+
+/**
+ * eeh_event_init - Start kernel thread to handle EEH events
+ *
+ * This routine is called to start the kernel thread for processing
+ * EEH event.
+ */
+int eeh_event_init(void)
+{
+ struct task_struct *t;
+ int ret = 0;
+
+ t = kthread_run(eeh_event_handler, NULL, "eehd");
+ if (IS_ERR(t)) {
+ ret = PTR_ERR(t);
+ pr_err("%s: Failed to start EEH daemon (%d)\n",
+ __func__, ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * eeh_send_failure_event - Generate a PCI error event
+ * @pe: EEH PE
+ *
+ * This routine can be called within an interrupt context;
+ * the actual event will be delivered in a normal context
+ * (from a workqueue).
+ */
+int __eeh_send_failure_event(struct eeh_pe *pe)
+{
+ unsigned long flags;
+ struct eeh_event *event;
+
+ event = kzalloc(sizeof(*event), GFP_ATOMIC);
+ if (!event) {
+ pr_err("EEH: out of memory, event not handled\n");
+ return -ENOMEM;
+ }
+ 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 */
+ 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, 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 (!force && event->pe &&
+ (event->pe->state & EEH_PE_ISOLATED))
+ continue;
+
+ if (!pe) {
+ list_del(&event->list);
+ kfree(event);
+ } else if (pe->type & EEH_PE_PHB) {
+ if (event->pe && event->pe->phb == pe->phb) {
+ list_del(&event->list);
+ kfree(event);
+ }
+ } else if (event->pe == pe) {
+ list_del(&event->list);
+ kfree(event);
+ }
+ }
+ spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
+}