[POWERPC] Fix irq enable/disable in smp_generic_take_timebase

Eran Ben-Avi <eranpublic@yahoo.com> pointed out that the arch/ppc version
of smp_generic_take_timebase disables interrupts on entry but exits without
restoring them.  However, both it and the arch/powerpc version have another
problem, which is that they use local_irq_disable/enable rather than
local_irq_save/restore, and they are called with interrupts disabled.

This fixes both problems; it changes a return to a break in the arch/ppc
version, and changes both versions to use local_irq_save/restore.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/arch/ppc/kernel/smp-tbsync.c b/arch/ppc/kernel/smp-tbsync.c
index 1576758debaf..d0cf3f86931d 100644
--- a/arch/ppc/kernel/smp-tbsync.c
+++ b/arch/ppc/kernel/smp-tbsync.c
@@ -47,8 +47,9 @@ void __devinit
 smp_generic_take_timebase( void )
 {
         int cmd, tbl, tbu;
+        unsigned long flags;
 
-        local_irq_disable();
+        local_irq_save(flags);
         while( !running )
                 ;
         rmb();
@@ -64,7 +65,7 @@ smp_generic_take_timebase( void )
                 tbu = tbsync->tbu;
                 tbsync->ack = 0;
                 if( cmd == kExit )
-                        return;
+                        break;
 
                 if( cmd == kSetAndTest ) {
                         while( tbsync->handshake )
@@ -77,7 +78,7 @@ smp_generic_take_timebase( void )
                 }
                 enter_contest( tbsync->mark, -1 );
         }
-        local_irq_enable();
+        local_irq_restore(flags);
 }
 
 static int __devinit