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>

3 files changed, 17 insertions, 2 deletions

diff --git a/arch/m68k/include/asm/entry.h b/arch/m68k/include/asm/entry.h
index c3c5a8643e15..622138dc7288 100644
--- a/arch/m68k/include/asm/entry.h
+++ b/arch/m68k/include/asm/entry.h
@@ -222,16 +222,24 @@
  * Non-MMU systems do not reserve %a2 in this way, and this definition is
  * not used for them.
  */
+#ifdef CONFIG_MMU
+
 #define curptr a2
 
 #define GET_CURRENT(tmp) get_current tmp
 .macro get_current reg=%d0
         movel   %sp,\reg
-        andw    #-THREAD_SIZE,\reg
+        andl    #-THREAD_SIZE,\reg
         movel   \reg,%curptr
         movel   %curptr@,%curptr
 .endm
 
+#else
+
+#define GET_CURRENT(tmp)
+
+#endif /* CONFIG_MMU */
+
 #else /* C source */
 
 #define STR(X) STR1(X)
diff --git a/arch/m68k/kernel/entry_no.S b/arch/m68k/kernel/entry_no.S
index ac86a9ffc1d7..d80cba45589f 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(buserr)
 
 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 @@ ENTRY(trap)
 .globl dbginterrupt
 ENTRY(dbginterrupt)
         SAVE_ALL_INT
+        GET_CURRENT(%d0)
         movel   %sp,%sp@-               /* stack frame pointer argument */
         jsr     dbginterrupt_c
         addql   #4,%sp
diff --git a/arch/m68k/platform/coldfire/entry.S b/arch/m68k/platform/coldfire/entry.S
index f567a163bc40..863889fc31c9 100644
--- a/arch/m68k/platform/coldfire/entry.S
+++ b/arch/m68k/platform/coldfire/entry.S
@@ -62,6 +62,7 @@ enosys:
 ENTRY(system_call)
         SAVE_ALL_SYS
         move    #0x2000,%sr             /* enable intrs again */
+        GET_CURRENT(%d2)
 
         cmpl    #NR_syscalls,%d0
         jcc     enosys
@@ -165,6 +166,7 @@ Lsignal_return:
  */
 ENTRY(inthandler)
         SAVE_ALL_INT
+        GET_CURRENT(%d2)
 
         movew   %sp@(PT_OFF_FORMATVEC),%d0 /* put exception # in d0 */
         andl    #0x03fc,%d0             /* mask out vector only */
@@ -190,7 +192,9 @@ ENTRY(resume)
         movel   %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
         RDUSP                                    /* movel %usp,%a3 */
         movel   %a3,%a0@(TASK_THREAD+THREAD_USP) /* save thread user stack */
-
+#ifdef CONFIG_MMU
+        movel   %a1,%a2                          /* set new current */
+#endif
         movel   %a1@(TASK_THREAD+THREAD_USP),%a3 /* restore thread user stack */
         WRUSP                                    /* movel %a3,%usp */
         movel   %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new kernel stack */