[PATCH 09/36] m68k: set register a2 to current if MMU enabled on ColdFire

gerg
2011-10-25T07:21:06Z

Virtual memory m68k systems build with register a2 dedicated to being the
current proc pointer. Add code to the ColdFire interrupt and exception
processing to set this on entry, and also at context switch time.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
arch/m68k/kernel/entry_no.S | 24 ++++++++++++++++++------
arch/m68k/platform/coldfire/entry.S | 18 +++++++++++++++++-
2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/arch/m68k/kernel/entry_no.S b/arch/m68k/kernel/entry_no.S
index 1b42890..050d7ea 100644
--- a/arch/m68k/kernel/entry_no.S
+++ b/arch/m68k/kernel/entry_no.S
@@ -44,8 +44,12 @@

ENTRY(buserr)
SAVE_ALL_INT
- moveq #-1,%d0
- movel %d0,%sp@(PT_OFF_ORIG_D0)
+#ifdef CONFIG_MMU
+ movel %sp,%d0 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d0 /* at start of kernel stack */
+ movel %d0,%a2
+ movel %a2@,%a2 /* current pointer into a2 */
+#endif
movel %sp,%sp@- /* stack frame pointer argument */
jsr buserr_c
addql #4,%sp
@@ -53,8 +57,12 @@ ENTRY(buserr)

ENTRY(trap)
SAVE_ALL_INT
- moveq #-1,%d0
- movel %d0,%sp@(PT_OFF_ORIG_D0)
+#ifdef CONFIG_MMU
+ movel %sp,%d0 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d0 /* at start of kernel stack */
+ movel %d0,%a2
+ movel %a2@,%a2 /* current pointer into a2 */
+#endif
movel %sp,%sp@- /* stack frame pointer argument */
jsr trap_c
addql #4,%sp
@@ -65,8 +73,12 @@ ENTRY(trap)
.globl dbginterrupt
ENTRY(dbginterrupt)
SAVE_ALL_INT
- moveq #-1,%d0
- movel %d0,%sp@(PT_OFF_ORIG_D0)
+#ifdef CONFIG_MMU
+ movel %sp,%d0 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d0 /* at start of kernel stack */
+ movel %d0,%a2
+ movel %a2@,%a2 /* current pointer into a2 */
+#endif
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 f567a16..5fc1f40 100644
--- a/arch/m68k/platform/coldfire/entry.S
+++ b/arch/m68k/platform/coldfire/entry.S
@@ -63,6 +63,13 @@ ENTRY(system_call)
SAVE_ALL_SYS
move #0x2000,%sr /* enable intrs again */

+#ifdef CONFIG_MMU
+ movel %sp,%d2 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d2 /* at start of kernel stack */
+ movel %d2,%a2
+ movel %a2@,%a2 /* current pointer into a2 */
+#endif
+
cmpl #NR_syscalls,%d0
jcc enosys
lea sys_call_table,%a0
@@ -166,6 +173,13 @@ Lsignal_return:
ENTRY(inthandler)
SAVE_ALL_INT

+#ifdef CONFIG_MMU
+ movel %sp,%d2 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d2 /* at start of kernel stack */
+ movel %d2,%a2
+ movel %a2@,%a2 /* current pointer into a2 */
+#endif
+
movew %sp@(PT_OFF_FORMATVEC),%d0 /* put exception # in d0 */
andl #0x03fc,%d0 /* mask out vector only */

@@ -190,7 +204,9 @@ 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 */
--
1.7.0.4