2 files changed, 14 insertions, 3 deletions

diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index bc08c98d008d..4845d51e88a6 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -952,8 +952,17 @@ ENDPROC(_evt_up_evt14)
 #ifdef CONFIG_IPIPE
 
 _resume_kernel_from_int:
+        r1 = LO(~0x8000) (Z);
+        r1 = r0 & r1;
+        r0 = 1;
+        r0 = r1 - r0;
+        r2 = r1 & r0;
+        cc = r2 == 0;
+        /* Sync the root stage only from the outer interrupt level. */
+        if !cc jump .Lnosync;
         r0.l = ___ipipe_sync_root;
         r0.h = ___ipipe_sync_root;
+        [--sp] = reti;
         [--sp] = rets;
         [--sp] = ( r7:4, p5:3 );
         SP += -12;
@@ -961,6 +970,8 @@ _resume_kernel_from_int:
         SP += 12;
         ( r7:4, p5:3 ) = [sp++];
         rets = [sp++];
+        reti = [sp++];
+.Lnosync:
         rts
 #elif defined(CONFIG_PREEMPT)
 
diff --git a/arch/blackfin/mach-common/interrupt.S b/arch/blackfin/mach-common/interrupt.S
index 2df37db3b49b..469ce7282dc8 100644
--- a/arch/blackfin/mach-common/interrupt.S
+++ b/arch/blackfin/mach-common/interrupt.S
@@ -274,16 +274,16 @@ ENDPROC(_evt_system_call)
  * level to EVT14 to prepare the caller for a normal interrupt
  * return through RTI.
  *
- * We currently use this facility in two occasions:
+ * We currently use this feature in two occasions:
  *
- * - to branch to __ipipe_irq_tail_hook as requested by a high
+ * - before branching to __ipipe_irq_tail_hook as requested by a high
  *   priority domain after the pipeline delivered an interrupt,
  *   e.g. such as Xenomai, in order to start its rescheduling
  *   procedure, since we may not switch tasks when IRQ levels are
  *   nested on the Blackfin, so we have to fake an interrupt return
  *   so that we may reschedule immediately.
  *
- * - to branch to sync_root_irqs, in order to play any interrupt
+ * - before branching to __ipipe_sync_root(), in order to play any interrupt
  *   pending for the root domain (i.e. the Linux kernel). This lowers
  *   the core priority level enough so that Linux IRQ handlers may
  *   never delay interrupts handled by high priority domains; we defer