[PATCH V2 6/8] MIPS: Add NMI notifier

[Kevin Cernekee <cernekee@gmail.com>]

Allow the board support code to register a raw notifier callback for
NMI, similar to what is done for CU2 exceptions.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
---

V2:

Use a raw notifier instead of a function pointer for NMI events.


 arch/mips/include/asm/traps.h |   12 ++++++++++++
 arch/mips/kernel/traps.c      |    9 +++++++++
 2 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/arch/mips/include/asm/traps.h b/arch/mips/include/asm/traps.h
index 90ff2f4..4edab87 100644
--- a/arch/mips/include/asm/traps.h
+++ b/arch/mips/include/asm/traps.h
@@ -25,4 +25,16 @@ extern void (*board_nmi_handler_setup)(void);
 extern void (*board_ejtag_handler_setup)(void);
 extern void (*board_bind_eic_interrupt)(int irq, int regset);
 
+extern int register_nmi_notifier(struct notifier_block *nb);
+
+#define nmi_notifier(fn, pri)						\
+({									\
+	static struct notifier_block fn##_nb = {			\
+		.notifier_call = fn,					\
+		.priority = pri						\
+	};								\
+									\
+	register_nmi_notifier(&fn##_nb);				\
+})
+
 #endif /* _ASM_TRAPS_H */
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 5c8a49d..33945aa 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1339,9 +1339,18 @@ void ejtag_exception_handler(struct pt_regs *regs)
 
 /*
  * NMI exception handler.
+ * No lock; only written during early bootup by CPU 0.
  */
+static RAW_NOTIFIER_HEAD(nmi_chain);
+
+int register_nmi_notifier(struct notifier_block *nb)
+{
+	return raw_notifier_chain_register(&nmi_chain, nb);
+}
+
 NORET_TYPE void ATTRIB_NORET nmi_exception_handler(struct pt_regs *regs)
 {
+	raw_notifier_call_chain(&nmi_chain, 0, regs);
 	bust_spinlocks(1);
 	printk("NMI taken!!!!\n");
 	die("NMI", regs);
-- 
1.7.6.3