x86/nmi: Use raw lock

register_nmi_handler() can be called from PREEMPT_RT atomic context
(e.g. wakeup_cpu_via_init_nmi() or native_stop_other_cpus()), and thus
ordinary spinlocks cannot be used.

Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/20170724213242.27598-1-swood@redhat.com

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 446c8aa..35aafc9 100644 (file)
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -39,26 +39,26 @@
 #include <trace/events/nmi.h>
 
 struct nmi_desc {
-       spinlock_t lock;
+       raw_spinlock_t lock;
        struct list_head head;
 };
 
 static struct nmi_desc nmi_desc[NMI_MAX] = 
 {
        {
-               .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[0].lock),
+               .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[0].lock),
                .head = LIST_HEAD_INIT(nmi_desc[0].head),
        },
        {
-               .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock),
+               .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock),
                .head = LIST_HEAD_INIT(nmi_desc[1].head),
        },
        {
-               .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[2].lock),
+               .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[2].lock),
                .head = LIST_HEAD_INIT(nmi_desc[2].head),
        },
        {
-               .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[3].lock),
+               .lock = __RAW_SPIN_LOCK_UNLOCKED(&nmi_desc[3].lock),
                .head = LIST_HEAD_INIT(nmi_desc[3].head),
        },
 
@@ -163,7 +163,7 @@ int __register_nmi_handler(unsigned int type, struct nmiaction *action)
 
        init_irq_work(&action->irq_work, nmi_max_handler);
 
-       spin_lock_irqsave(&desc->lock, flags);
+       raw_spin_lock_irqsave(&desc->lock, flags);
 
        /*
         * Indicate if there are multiple registrations on the
@@ -181,7 +181,7 @@ int __register_nmi_handler(unsigned int type, struct nmiaction *action)
        else
                list_add_tail_rcu(&action->list, &desc->head);
        
-       spin_unlock_irqrestore(&desc->lock, flags);
+       raw_spin_unlock_irqrestore(&desc->lock, flags);
        return 0;
 }
 EXPORT_SYMBOL(__register_nmi_handler);
@@ -192,7 +192,7 @@ void unregister_nmi_handler(unsigned int type, const char *name)
        struct nmiaction *n;
        unsigned long flags;
 
-       spin_lock_irqsave(&desc->lock, flags);
+       raw_spin_lock_irqsave(&desc->lock, flags);
 
        list_for_each_entry_rcu(n, &desc->head, list) {
                /*
@@ -207,7 +207,7 @@ void unregister_nmi_handler(unsigned int type, const char *name)
                }
        }
 
-       spin_unlock_irqrestore(&desc->lock, flags);
+       raw_spin_unlock_irqrestore(&desc->lock, flags);
        synchronize_rcu();
 }
 EXPORT_SYMBOL_GPL(unregister_nmi_handler);