m68k: set register a2 to current if MMU enabled on ColdFire

Virtual memory m68k systems build with register a2 dedicated to being the
current proc pointer (non-MMU don't do this). Add code to the ColdFire
interrupt and exception processing to set this on entry, and at context
switch time. We use the same GET_CURRENT() macro that MMU enabled code
uses - modifying it so that the assembler is ColdFire clean.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Matt Waddel <mwaddel@yahoo.com>
Acked-by: Kurt Mahan <kmahan@xmission.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
diff --git a/arch/m68k/kernel/entry_no.S b/arch/m68k/kernel/entry_no.S
index ac86a9f..d80cba4 100644
--- a/arch/m68k/kernel/entry_no.S
+++ b/arch/m68k/kernel/entry_no.S
@@ -44,6 +44,7 @@
 
 ENTRY(buserr)
 	SAVE_ALL_INT
+	GET_CURRENT(%d0)
 	movel	%sp,%sp@- 		/* stack frame pointer argument */
 	jsr	buserr_c
 	addql	#4,%sp
@@ -51,6 +52,7 @@
 
 ENTRY(trap)
 	SAVE_ALL_INT
+	GET_CURRENT(%d0)
 	movel	%sp,%sp@- 		/* stack frame pointer argument */
 	jsr	trap_c
 	addql	#4,%sp
@@ -61,6 +63,7 @@
 .globl dbginterrupt
 ENTRY(dbginterrupt)
 	SAVE_ALL_INT
+	GET_CURRENT(%d0)
 	movel	%sp,%sp@- 		/* stack frame pointer argument */
 	jsr	dbginterrupt_c
 	addql	#4,%sp