From 9a5f37798ca0c3e4664d83f2b2174d8e11ea14de Mon Sep 17 00:00:00 2001
From: Philippe Gerum <rpm@xenomai.org>
Date: Mon, 22 Jun 2009 18:23:32 +0200
Subject: [PATCH] --- yaml --- r: 162675 b: refs/heads/master c:
 6b8019c85e18295466095a5778a14c1e9a067554 h: refs/heads/master i:   162673:
 1fb7c813ae9368c5f399c63af9a994ff9eb0862d   162671:
 21c6c68860c2a3cb42727dbc817ca3d2129006b7 v: v3

---
 [refs]                             |  2 +-
 trunk/arch/blackfin/kernel/entry.S | 24 ++++++++++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 1256c301b267..5de66e5519ee 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bc569f1a77199926be97ba6266dbea27768264df
+refs/heads/master: 6b8019c85e18295466095a5778a14c1e9a067554
diff --git a/trunk/arch/blackfin/kernel/entry.S b/trunk/arch/blackfin/kernel/entry.S
index a9cfba9946b5..3f8769b7db54 100644
--- a/trunk/arch/blackfin/kernel/entry.S
+++ b/trunk/arch/blackfin/kernel/entry.S
@@ -43,8 +43,28 @@
 
 ENTRY(_ret_from_fork)
 #ifdef CONFIG_IPIPE
-	[--sp] = reti; 		/* IRQs on. */
-	SP += 4;
+	/*
+	 * Hw IRQs are off on entry, and we don't want the scheduling tail
+	 * code to starve high priority domains from interrupts while it
+	 * runs. Therefore we first stall the root stage to have the
+	 * virtual interrupt state reflect IMASK.
+	 */
+	p0.l = ___ipipe_root_status;
+	p0.h = ___ipipe_root_status;
+	r4 = [p0];
+	bitset(r4, 0);
+	[p0] = r4;
+	/*
+	 * Then we may enable hw IRQs, allowing preemption from high
+	 * priority domains. schedule_tail() will do local_irq_enable()
+	 * since Blackfin does not define __ARCH_WANT_UNLOCKED_CTXSW, so
+	 * there is no need to unstall the root domain by ourselves
+	 * afterwards.
+	 */
+	p0.l = _bfin_irq_flags;
+	p0.h = _bfin_irq_flags;
+	r4 = [p0];
+	sti r4;
 #endif /* CONFIG_IPIPE */
 	SP += -12;
 	call _schedule_tail;