diff options
Diffstat (limited to 'arch/powerpc/kernel/eeh_event.c')
| -rw-r--r-- | arch/powerpc/kernel/eeh_event.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/eeh_event.c b/arch/powerpc/kernel/eeh_event.c new file mode 100644 index 000000000..c23a454af --- /dev/null +++ b/arch/powerpc/kernel/eeh_event.c @@ -0,0 +1,201 @@ +// 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); +} |