[S390] rework idle code

Whenever the cpu loads an enabled wait PSW it will appear as idle to the
underlying host system. The code in default_idle calls vtime_stop_cpu
which does the necessary voodoo to get the cpu time accounting right.
The udelay code just loads an enabled wait PSW. To correct this rework
the vtime_stop_cpu/vtime_start_cpu logic and move the difficult parts
to entry[64].S, vtime_stop_cpu can now be called from anywhere and
vtime_start_cpu is gone. The correction of the cpu time during wakeup
from an enabled wait PSW is done with a critical section in entry[64].S.
As vtime_start_cpu is gone, s390_idle_check can be removed as well.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 1 insertions, 8 deletions

diff --git a/arch/s390/include/asm/cputime.h b/arch/s390/include/asm/cputime.h
index c23c3900c304..24ef186a1c4f 100644
--- a/arch/s390/include/asm/cputime.h
+++ b/arch/s390/include/asm/cputime.h
@@ -170,24 +170,17 @@ struct s390_idle_data {
 	unsigned int sequence;
 	unsigned long long idle_count;
 	unsigned long long idle_enter;
+	unsigned long long idle_exit;
 	unsigned long long idle_time;
 	int nohz_delay;
 };
 
 DECLARE_PER_CPU(struct s390_idle_data, s390_idle);
 
-void vtime_start_cpu(__u64 int_clock, __u64 enter_timer);
 cputime64_t s390_get_idle_time(int cpu);
 
 #define arch_idle_time(cpu) s390_get_idle_time(cpu)
 
-static inline void s390_idle_check(struct pt_regs *regs, __u64 int_clock,
-				   __u64 enter_timer)
-{
-	if (regs->psw.mask & PSW_MASK_WAIT)
-		vtime_start_cpu(int_clock, enter_timer);
-}
-
 static inline int s390_nohz_delay(int cpu)
 {
 	return __get_cpu_var(s390_idle).nohz_delay != 0;