[PATCH] irq code: Add coherence test for PREEMPT_ACTIVE

After porting this fixlet to UML:

http://linux.bkbits.net:8080/linux-2.5/cset@41791ab52lfMuF2i3V-eTIGRBbDYKQ

, I've also added a warning which should refuse compilation with insane values
for PREEMPT_ACTIVE...  maybe we should simply move PREEMPT_ACTIVE out of
architectures using GENERIC_IRQS.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index ebc712e..8336dba 100644 (file)
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -43,13 +43,17 @@
 #define __IRQ_MASK(x)  ((1UL << (x))-1)
 
 #define PREEMPT_MASK   (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
-#define HARDIRQ_MASK   (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
 #define SOFTIRQ_MASK   (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
+#define HARDIRQ_MASK   (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
 
 #define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
 #define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
 #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
 
+#if PREEMPT_ACTIVE < (1 << (HARDIRQ_SHIFT + HARDIRQ_BITS))
+#error PREEMPT_ACTIVE is too low!
+#endif
+
 #define hardirq_count()        (preempt_count() & HARDIRQ_MASK)
 #define softirq_count()        (preempt_count() & SOFTIRQ_MASK)
 #define irq_count()    (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK))