Kprobes: The ON/OFF knob thru debugfs

[linux-2.6.git] / arch / s390 / lib / delay.c

diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 027c4742a0017a2cdef12b51a4dd282709dc59b9..70f2a862b670649e296d1c6e5277f01241161a11 100644 (file)
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -1,5 +1,5 @@
 /*
- *  arch/s390/kernel/delay.c
+ *  arch/s390/lib/delay.c
  *    Precise Delay Loops for S390
  *
  *  S390 version
@@ -13,10 +13,9 @@
 
 #include <linux/sched.h>
 #include <linux/delay.h>
-
-#ifdef CONFIG_SMP
-#include <asm/smp.h>
-#endif
+#include <linux/timex.h>
+#include <linux/irqflags.h>
+#include <linux/interrupt.h>
 
 void __delay(unsigned long loops)
 {
@@ -31,17 +30,45 @@ void __delay(unsigned long loops)
 }
 
 /*
- * Waits for 'usecs' microseconds using the tod clock, giving up the time slice
- * of the virtual PU inbetween to avoid congestion.
+ * Waits for 'usecs' microseconds using the TOD clock comparator.
  */
 void __udelay(unsigned long usecs)
 {
-       uint64_t start_cc;
+       u64 end, time, jiffy_timer = 0;
+       unsigned long flags, cr0, mask, dummy;
+       int irq_context;
+
+       irq_context = in_interrupt();
+       if (!irq_context)
+               local_bh_disable();
+       local_irq_save(flags);
+       if (raw_irqs_disabled_flags(flags)) {
+               jiffy_timer = S390_lowcore.jiffy_timer;
+               S390_lowcore.jiffy_timer = -1ULL - (4096 << 12);
+               __ctl_store(cr0, 0, 0);
+               dummy = (cr0 & 0xffff00e0) | 0x00000800;
+               __ctl_load(dummy , 0, 0);
+               mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
+       } else
+               mask = psw_kernel_bits | PSW_MASK_WAIT |
+                       PSW_MASK_EXT | PSW_MASK_IO;
+
+       end = get_clock() + ((u64) usecs << 12);
+       do {
+               time = end < S390_lowcore.jiffy_timer ?
+                       end : S390_lowcore.jiffy_timer;
+               set_clock_comparator(time);
+               trace_hardirqs_on();
+               __load_psw_mask(mask);
+               local_irq_disable();
+       } while (get_clock() < end);
 
-        if (usecs == 0)
-                return;
-       start_cc = get_clock();
-        do {
-               cpu_relax();
-       } while (((get_clock() - start_cc)/4096) < usecs);
+       if (raw_irqs_disabled_flags(flags)) {
+               __ctl_load(cr0, 0, 0);
+               S390_lowcore.jiffy_timer = jiffy_timer;
+       }
+       if (!irq_context)
+               _local_bh_enable();
+       set_clock_comparator(S390_lowcore.jiffy_timer);
+       local_irq_restore(flags);
 }