MIPS: Loongson: Add NMI handler support

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J . Hill <Steven.Hill@cavium.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16587/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/loongson64/common/init.c

@@ -10,13 +10,25 @@
 
 #include <linux/bootmem.h>
 #include <asm/bootinfo.h>
+#include <asm/traps.h>
 #include <asm/smp-ops.h>
+#include <asm/cacheflush.h>
 
 #include <loongson.h>
 
 /* Loongson CPU address windows config space base address */
 unsigned long __maybe_unused _loongson_addrwincfg_base;
 
+static void __init mips_nmi_setup(void)
+{
+	void *base;
+	extern char except_vec_nmi;
+
+	base = (void *)(CAC_BASE + 0x380);
+	memcpy(base, &except_vec_nmi, 0x80);
+	flush_icache_range((unsigned long)base, (unsigned long)base + 0x80);
+}
+
 void __init prom_init(void)
 {
 #ifdef CONFIG_CPU_SUPPORTS_ADDRWINCFG
@@ -40,6 +52,7 @@ void __init prom_init(void)
 	/*init the uart base address */
 	prom_init_uart_base();
 	register_smp_ops(&loongson3_smp_ops);
+	board_nmi_handler_setup = mips_nmi_setup;
 }
 
 void __init prom_free_prom_memory(void)