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-rw-r--r--arch/s390/include/asm/barrier.h35
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diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h
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+++ b/arch/s390/include/asm/barrier.h
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+/*
+ * Copyright IBM Corp. 1999, 2009
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#ifndef __ASM_BARRIER_H
+#define __ASM_BARRIER_H
+
+/*
+ * Force strict CPU ordering.
+ * And yes, this is required on UP too when we're talking
+ * to devices.
+ *
+ * This is very similar to the ppc eieio/sync instruction in that is
+ * does a checkpoint syncronisation & makes sure that
+ * all memory ops have completed wrt other CPU's ( see 7-15 POP DJB ).
+ */
+
+#define eieio() asm volatile("bcr 15,0" : : : "memory")
+#define SYNC_OTHER_CORES(x) eieio()
+#define mb() eieio()
+#define rmb() eieio()
+#define wmb() eieio()
+#define read_barrier_depends() do { } while(0)
+#define smp_mb() mb()
+#define smp_rmb() rmb()
+#define smp_wmb() wmb()
+#define smp_read_barrier_depends() read_barrier_depends()
+#define smp_mb__before_clear_bit() smp_mb()
+#define smp_mb__after_clear_bit() smp_mb()
+
+#define set_mb(var, value) do { var = value; mb(); } while (0)
+
+#endif /* __ASM_BARRIER_H */