commit e9fcffa49376b37518baf71a47adc15e74b2434c
author Greg Ungerer <gerg@uclinux.org> Wed Oct 19 13:58:55 2011 +1000
committer Greg Ungerer <gerg@uclinux.org> Fri Dec 30 10:20:45 2011 +1000
tree 8040672d03de61517a33e1936e1fba0188cccb1a
parent ed865e31a8273be200db9ddcdb6b844e48777abd

m68k: adjustments to stack frame for ColdFire with MMU enabled

The exception return stack adjustment required by ColdFire when running
with the MMU enabled is not completely identical to 680x0 processors.
Specifically the format type 4 stack frame doesn't need any stack
adjustment on exception return. And the ColdFire always must return with
a frame type of 4, not 0.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Matt Waddel <mwaddel@yahoo.com>
Acked-by: Kurt Mahan <kmahan@xmission.com>

arch/m68k/kernel/signal_mm.c

diff --git a/arch/m68k/kernel/signal_mm.c b/arch/m68k/kernel/signal_mm.c
index a0afc23..5f6b3d0 100644
--- a/arch/m68k/kernel/signal_mm.c
+++ b/arch/m68k/kernel/signal_mm.c
@@ -56,7 +56,11 @@
   [1]	= -1, /* sizeof(((struct frame *)0)->un.fmt1), */
   [2]	= sizeof(((struct frame *)0)->un.fmt2),
   [3]	= sizeof(((struct frame *)0)->un.fmt3),
+#ifdef CONFIG_COLDFIRE
+  [4]	= 0,
+#else
   [4]	= sizeof(((struct frame *)0)->un.fmt4),
+#endif
   [5]	= -1, /* sizeof(((struct frame *)0)->un.fmt5), */
   [6]	= -1, /* sizeof(((struct frame *)0)->un.fmt6), */
   [7]	= sizeof(((struct frame *)0)->un.fmt7),
@@ -84,7 +88,11 @@
 	regs->stkadj = frame_extra_sizes[regs->format];
 	tregs =	(struct pt_regs *)((long)regs + regs->stkadj);
 	tregs->vector = regs->vector;
+#ifdef CONFIG_COLDFIRE
+	tregs->format = 4;
+#else
 	tregs->format = 0;
+#endif
 	tregs->pc = fixup->fixup;
 	tregs->sr = regs->sr;
 
@@ -336,8 +344,12 @@
 		regs->format = formatvec >> 12;
 		regs->vector = formatvec & 0xfff;
 #define frame_offset (sizeof(struct pt_regs)+sizeof(struct switch_stack))
-		__asm__ __volatile__
-			("   movel %0,%/a0\n\t"
+		__asm__ __volatile__ (
+#ifdef CONFIG_COLDFIRE
+			 "   movel %0,%/sp\n\t"
+			 "   bra ret_from_signal\n"
+#else
+			 "   movel %0,%/a0\n\t"
 			 "   subl %1,%/a0\n\t"     /* make room on stack */
 			 "   movel %/a0,%/sp\n\t"  /* set stack pointer */
 			 /* move switch_stack and pt_regs */
@@ -350,6 +362,7 @@
 			 "2: movel %4@+,%/a0@+\n\t"
 			 "   dbra %1,2b\n\t"
 			 "   bral ret_from_signal\n"
+#endif
 			 : /* no outputs, it doesn't ever return */
 			 : "a" (sw), "d" (fsize), "d" (frame_offset/4-1),
 			   "n" (frame_offset), "a" (buf + fsize/4)