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-rw-r--r--include/asm-sparc64/backoff.h28
1 files changed, 28 insertions, 0 deletions
diff --git a/include/asm-sparc64/backoff.h b/include/asm-sparc64/backoff.h
new file mode 100644
index 00000000000..0e32f8b62fd
--- /dev/null
+++ b/include/asm-sparc64/backoff.h
@@ -0,0 +1,28 @@
+#ifndef _SPARC64_BACKOFF_H
+#define _SPARC64_BACKOFF_H
+
+#define BACKOFF_LIMIT (4 * 1024)
+
+#ifdef CONFIG_SMP
+
+#define BACKOFF_SETUP(reg) \
+ mov 1, reg
+
+#define BACKOFF_SPIN(reg, tmp, label) \
+ mov reg, tmp; \
+88: brnz,pt tmp, 88b; \
+ sub tmp, 1, tmp; \
+ cmp reg, BACKOFF_LIMIT; \
+ bg,pn %xcc, label; \
+ nop; \
+ ba,pt %xcc, label; \
+ sllx reg, 1, reg;
+
+#else
+
+#define BACKOFF_SETUP(reg)
+#define BACKOFF_SPIN(reg, tmp, label)
+
+#endif
+
+#endif /* _SPARC64_BACKOFF_H */