[PATCH] Fix PREEMPT_ACTIVE definition

When the generic IRQ stuff went in, it seems that HARDIRQ_BITS got bumped
from 9 (for ppc64) up to 12.  Consequently, the PREEMPT_ACTIVE bit is now
within HARDIRQ_MASK, and I get in_interrupt() falsely returning true when
PREEMPT_ACTIVE is set, and thus a BUG_ON tripping in arch/ppc64/mm/tlb.c.

The patch below fixes this by changing PREEMPT_ACTIVE to 0x10000000.  I
have changed the PREEMPT_ACTIVE definitions for each of the architectures
that define CONFIG_GENERIC_HARDIRQS (i386, ppc, ppc64, x86_64) and fixed
the comment in include/linux/hardirq.h.  We could perhaps move the
PREEMPT_ACTIVE definition to include/linux/hardirq.h - I don't know why it
is still per-arch.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/asm-i386/thread_info.h

@@ -51,7 +51,7 @@ struct thread_info {
 
 #endif
 
-#define PREEMPT_ACTIVE		0x4000000
+#define PREEMPT_ACTIVE		0x10000000
 #ifdef CONFIG_4KSTACKS
 #define THREAD_SIZE            (4096)
 #else

include/asm-ppc/thread_info.h

@@ -65,7 +65,7 @@ static inline struct thread_info *current_thread_info(void)
  */
 #define THREAD_SIZE		8192	/* 2 pages */
 
-#define PREEMPT_ACTIVE		0x4000000
+#define PREEMPT_ACTIVE		0x10000000
 
 /*
  * thread information flag bit numbers

include/asm-ppc64/thread_info.h

@@ -82,7 +82,7 @@ static inline struct thread_info *current_thread_info(void)
 
 #endif /* __ASSEMBLY__ */
 
-#define PREEMPT_ACTIVE		0x4000000
+#define PREEMPT_ACTIVE		0x10000000
 
 /*
  * thread information flag bit numbers

include/asm-x86_64/thread_info.h

@@ -125,7 +125,7 @@ static inline struct thread_info *stack_thread_info(void)
 /* work to do on any return to user space */
 #define _TIF_ALLWORK_MASK 0x0000FFFF	
 
-#define PREEMPT_ACTIVE     0x4000000
+#define PREEMPT_ACTIVE     0x10000000
 
 /*
  * Thread-synchronous status.

include/linux/hardirq.h

@@ -14,7 +14,7 @@
  * - bits 8-15 are the softirq count (max # of softirqs: 256)
  * - bits 16-27 are the hardirq count (max # of hardirqs: 4096)
  *
- * - ( bit 26 is the PREEMPT_ACTIVE flag. )
+ * - ( bit 28 is the PREEMPT_ACTIVE flag. )
  *
  * PREEMPT_MASK: 0x000000ff
  * SOFTIRQ_MASK: 0x0000ff00