[uClinux-dev] [RFC 07/11] coldfire add support for kernel preemption

[Sebastian Siewior]

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, I don't touch it. Kconfig
enables the preemption item only on coldfire.

Signed-off-by: Sebastian Siewior <[EMAIL PROTECTED]>
--- a/arch/m68knommu/Kconfig
+++ b/arch/m68knommu/Kconfig
@@ -671,7 +671,9 @@ config ROMKERNEL
 endchoice
 
 source "kernel/time/Kconfig"
-
+if COLDFIRE
+source "kernel/Kconfig.preempt"
+endif
 source "mm/Kconfig"
 
 endmenu
--- a/arch/m68knommu/kernel/asm-offsets.c
+++ b/arch/m68knommu/kernel/asm-offsets.c
@@ -91,6 +91,7 @@ int main(void)
        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;
--- a/arch/m68knommu/platform/coldfire/entry.S
+++ b/arch/m68knommu/platform/coldfire/entry.S
@@ -106,6 +106,22 @@ ret_from_exception:
        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 */

-- 

_______________________________________________
uClinux-dev mailing list
uClinux-dev@uclinux.org
http://mailman.uclinux.org/mailman/listinfo/uclinux-dev
This message was resent by uclinux-dev@uclinux.org
To unsubscribe see:
http://mailman.uclinux.org/mailman/options/uclinux-dev