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-rw-r--r--arch/x86/include/asm/nmi.h18
-rw-r--r--arch/x86/kernel/nmi.c153
2 files changed, 171 insertions, 0 deletions
diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h
index 4886a68f267e..480b69b75756 100644
--- a/arch/x86/include/asm/nmi.h
+++ b/arch/x86/include/asm/nmi.h
@@ -42,6 +42,24 @@ void arch_trigger_all_cpu_backtrace(void);
#define NMI_LOCAL_NORMAL_PRIOR (NMI_LOCAL_BIT | NMI_NORMAL_PRIOR)
#define NMI_LOCAL_LOW_PRIOR (NMI_LOCAL_BIT | NMI_LOW_PRIOR)
+#define NMI_FLAG_FIRST 1
+
+enum {
+ NMI_LOCAL=0,
+ NMI_UNKNOWN,
+ NMI_MAX
+};
+
+#define NMI_DONE 0
+#define NMI_HANDLED 1
+
+typedef int (*nmi_handler_t)(unsigned int, struct pt_regs *);
+
+int register_nmi_handler(unsigned int, nmi_handler_t, unsigned long,
+ const char *);
+
+void unregister_nmi_handler(unsigned int, const char *);
+
void stop_nmi(void);
void restart_nmi(void);
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 68d758aca8cd..327748d4f6b0 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -13,6 +13,9 @@
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <linux/nmi.h>
+#include <linux/delay.h>
+#include <linux/hardirq.h>
+#include <linux/slab.h>
#if defined(CONFIG_EDAC)
#include <linux/edac.h>
@@ -21,6 +24,33 @@
#include <linux/atomic.h>
#include <asm/traps.h>
#include <asm/mach_traps.h>
+#include <asm/nmi.h>
+
+#define NMI_MAX_NAMELEN 16
+struct nmiaction {
+ struct list_head list;
+ nmi_handler_t handler;
+ unsigned int flags;
+ char *name;
+};
+
+struct nmi_desc {
+ spinlock_t lock;
+ struct list_head head;
+};
+
+static struct nmi_desc nmi_desc[NMI_MAX] =
+{
+ {
+ .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[0].lock),
+ .head = LIST_HEAD_INIT(nmi_desc[0].head),
+ },
+ {
+ .lock = __SPIN_LOCK_UNLOCKED(&nmi_desc[1].lock),
+ .head = LIST_HEAD_INIT(nmi_desc[1].head),
+ },
+
+};
static int ignore_nmis;
@@ -38,6 +68,129 @@ static int __init setup_unknown_nmi_panic(char *str)
}
__setup("unknown_nmi_panic", setup_unknown_nmi_panic);
+#define nmi_to_desc(type) (&nmi_desc[type])
+
+static int notrace __kprobes nmi_handle(unsigned int type, struct pt_regs *regs)
+{
+ struct nmi_desc *desc = nmi_to_desc(type);
+ struct nmiaction *a;
+ int handled=0;
+
+ rcu_read_lock();
+
+ /*
+ * NMIs are edge-triggered, which means if you have enough
+ * of them concurrently, you can lose some because only one
+ * can be latched at any given time. Walk the whole list
+ * to handle those situations.
+ */
+ list_for_each_entry_rcu(a, &desc->head, list) {
+
+ handled += a->handler(type, regs);
+
+ }
+
+ rcu_read_unlock();
+
+ /* return total number of NMI events handled */
+ return handled;
+}
+
+static int __setup_nmi(unsigned int type, struct nmiaction *action)
+{
+ struct nmi_desc *desc = nmi_to_desc(type);
+ unsigned long flags;
+
+ spin_lock_irqsave(&desc->lock, flags);
+
+ /*
+ * some handlers need to be executed first otherwise a fake
+ * event confuses some handlers (kdump uses this flag)
+ */
+ if (action->flags & NMI_FLAG_FIRST)
+ list_add_rcu(&action->list, &desc->head);
+ else
+ list_add_tail_rcu(&action->list, &desc->head);
+
+ spin_unlock_irqrestore(&desc->lock, flags);
+ return 0;
+}
+
+static struct nmiaction *__free_nmi(unsigned int type, const char *name)
+{
+ struct nmi_desc *desc = nmi_to_desc(type);
+ struct nmiaction *n;
+ unsigned long flags;
+
+ spin_lock_irqsave(&desc->lock, flags);
+
+ list_for_each_entry_rcu(n, &desc->head, list) {
+ /*
+ * the name passed in to describe the nmi handler
+ * is used as the lookup key
+ */
+ if (!strcmp(n->name, name)) {
+ WARN(in_nmi(),
+ "Trying to free NMI (%s) from NMI context!\n", n->name);
+ list_del_rcu(&n->list);
+ break;
+ }
+ }
+
+ spin_unlock_irqrestore(&desc->lock, flags);
+ synchronize_rcu();
+ return (n);
+}
+
+int register_nmi_handler(unsigned int type, nmi_handler_t handler,
+ unsigned long nmiflags, const char *devname)
+{
+ struct nmiaction *action;
+ int retval = -ENOMEM;
+
+ if (!handler)
+ return -EINVAL;
+
+ action = kzalloc(sizeof(struct nmiaction), GFP_KERNEL);
+ if (!action)
+ goto fail_action;
+
+ action->handler = handler;
+ action->flags = nmiflags;
+ action->name = kstrndup(devname, NMI_MAX_NAMELEN, GFP_KERNEL);
+ if (!action->name)
+ goto fail_action_name;
+
+ retval = __setup_nmi(type, action);
+
+ if (retval)
+ goto fail_setup_nmi;
+
+ return retval;
+
+fail_setup_nmi:
+ kfree(action->name);
+fail_action_name:
+ kfree(action);
+fail_action:
+
+ return retval;
+}
+EXPORT_SYMBOL_GPL(register_nmi_handler);
+
+void unregister_nmi_handler(unsigned int type, const char *name)
+{
+ struct nmiaction *a;
+
+ a = __free_nmi(type, name);
+ if (a) {
+ kfree(a->name);
+ kfree(a);
+ }
+}
+
+EXPORT_SYMBOL_GPL(unregister_nmi_handler);
+
static notrace __kprobes void
pci_serr_error(unsigned char reason, struct pt_regs *regs)
{