[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>
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index db92f04..9f1f71e 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -13,6 +13,7 @@
#include <linux/irqflags.h>
#include <linux/interrupt.h>
#include <asm/div64.h>
+#include <asm/timer.h>
void __delay(unsigned long loops)
{
@@ -28,36 +29,33 @@
static void __udelay_disabled(unsigned long long usecs)
{
- unsigned long mask, cr0, cr0_saved;
- u64 clock_saved;
- u64 end;
+ unsigned long cr0, cr6, new;
+ u64 clock_saved, end;
- mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_WAIT |
- PSW_MASK_EXT | PSW_MASK_MCHECK;
end = get_clock() + (usecs << 12);
clock_saved = local_tick_disable();
- __ctl_store(cr0_saved, 0, 0);
- cr0 = (cr0_saved & 0xffff00e0) | 0x00000800;
- __ctl_load(cr0 , 0, 0);
+ __ctl_store(cr0, 0, 0);
+ __ctl_store(cr6, 6, 6);
+ new = (cr0 & 0xffff00e0) | 0x00000800;
+ __ctl_load(new , 0, 0);
+ new = 0;
+ __ctl_load(new, 6, 6);
lockdep_off();
do {
set_clock_comparator(end);
- trace_hardirqs_on();
- __load_psw_mask(mask);
+ vtime_stop_cpu();
local_irq_disable();
} while (get_clock() < end);
lockdep_on();
- __ctl_load(cr0_saved, 0, 0);
+ __ctl_load(cr0, 0, 0);
+ __ctl_load(cr6, 6, 6);
local_tick_enable(clock_saved);
}
static void __udelay_enabled(unsigned long long usecs)
{
- unsigned long mask;
- u64 clock_saved;
- u64 end;
+ u64 clock_saved, end;
- mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT | PSW_MASK_IO;
end = get_clock() + (usecs << 12);
do {
clock_saved = 0;
@@ -65,8 +63,7 @@
clock_saved = local_tick_disable();
set_clock_comparator(end);
}
- trace_hardirqs_on();
- __load_psw_mask(mask);
+ vtime_stop_cpu();
local_irq_disable();
if (clock_saved)
local_tick_enable(clock_saved);