---

yaml --- r: 80152 b: refs/heads/master c: fde1b3f h: refs/heads/master v: v3
git-mirror · Jan 30, 2008 · 2aedbbc · 2aedbbc
1 parent c14d98f
commit 2aedbbc
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Showing 2 changed files with 14 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2a10e7c41254941cac87be1eccdcb6379ce097f5
+refs/heads/master: fde1b3fa947c2512e3715962ebb1d3a6a9b9bb7d
diff --git a/trunk/include/asm-x86/system.h b/trunk/include/asm-x86/system.h
@@ -5,6 +5,7 @@
 #include <asm/segment.h>
 #include <asm/cpufeature.h>
 #include <asm/cmpxchg.h>
+#include <asm/nops.h>
 
 #include <linux/kernel.h>
 #include <linux/irqflags.h>
@@ -395,5 +396,17 @@ void default_idle(void);
 #define set_mb(var, value) do { var = value; barrier(); } while (0)
 #endif
 
+/*
+ * Stop RDTSC speculation. This is needed when you need to use RDTSC
+ * (or get_cycles or vread that possibly accesses the TSC) in a defined
+ * code region.
+ *
+ * (Could use an alternative three way for this if there was one.)
+ */
+static inline void rdtsc_barrier(void)
+{
+	alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
+	alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
+}
 
 #endif