m68knommu: ColdFire add support for kernel preemption
As the subject says this patch adds the support for kernel preemption
on m68knommu Coldfire. I thing the same changes could be applied to
68360 & 68328 but since I don't have the HW for testing, I don't touch it.
Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/m68knommu/kernel/asm-offsets.c b/arch/m68knommu/kernel/asm-offsets.c
index fd0c685..c785d07 100644
--- a/arch/m68knommu/kernel/asm-offsets.c
+++ b/arch/m68knommu/kernel/asm-offsets.c
@@ -87,6 +87,7 @@
DEFINE(TI_TASK, offsetof(struct thread_info, task));
DEFINE(TI_EXECDOMAIN, offsetof(struct thread_info, exec_domain));
DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
+ DEFINE(TI_PREEMPTCOUNT, offsetof(struct thread_info, preempt_count));
DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
return 0;
diff --git a/arch/m68knommu/platform/coldfire/entry.S b/arch/m68knommu/platform/coldfire/entry.S
index 111b66d..1af7c1d 100644
--- a/arch/m68knommu/platform/coldfire/entry.S
+++ b/arch/m68knommu/platform/coldfire/entry.S
@@ -106,6 +106,22 @@
btst #5,%sp@(PT_SR) /* check if returning to kernel */
jeq Luser_return /* if so, skip resched, signals */
+#ifdef CONFIG_PREEMPT
+ movel %sp,%d1 /* get thread_info pointer */
+ andl #-THREAD_SIZE,%d1 /* at base of kernel stack */
+ movel %d1,%a0
+ movel %a0@(TI_FLAGS),%d1 /* get thread_info->flags */
+ andl #_TIF_NEED_RESCHED,%d1
+ jeq Lkernel_return
+
+ movel %a0@(TI_PREEMPTCOUNT),%d1
+ cmpl #0,%d1
+ jne Lkernel_return
+
+ pea Lkernel_return
+ jmp preempt_schedule_irq /* preempt the kernel */
+#endif
+
Lkernel_return:
moveml %sp@,%d1-%d5/%a0-%a2
lea %sp@(32),%sp /* space for 8 regs */
