Blackfin arch: add an exception request/free api

add an exception request/free api similar to the interrupt request/fre
api so people can utilize the free software based exceptions for their
own purposes

Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

diff --git a/include/asm-blackfin/irq_handler.h b/include/asm-blackfin/irq_handler.h
index f13cd73..19534c1 100644
--- a/include/asm-blackfin/irq_handler.h
+++ b/include/asm-blackfin/irq_handler.h
@@ -20,5 +20,13 @@
 asmlinkage void evt_soft_int1(void);
 asmlinkage void evt_system_call(void);
 asmlinkage void init_exception_buff(void);
+asmlinkage void trap_c(struct pt_regs *fp);
+asmlinkage void ex_replaceable(void);
+
+extern void *ex_table[];
+extern void return_from_exception(void);
+
+extern int bfin_request_exception(unsigned int exception, void (*handler)(void));
+extern int bfin_free_exception(unsigned int exception, void (*handler)(void));
 
 #endif