Add missing rcu_cmpxchg_pointer define

[urcu.git] / arch_x86.h

diff --git a/arch_x86.h b/arch_x86.h
index 4a2573e0f52934e3a2635516ad5f66cfd7c5c563..8a5732536c9d3106af919b5467dab1f58c5f9313 100644 (file)
--- a/arch_x86.h
+++ b/arch_x86.h
@@ -94,6 +94,26 @@ static inline void cpu_relax(void)
        rep_nop();
 }
 
+/*
+ * Serialize core instruction execution. Also acts as a compiler barrier.
+ */
+#ifdef __PIC__
+/*
+ * Cannot use cpuid because it clobbers the ebx register and clashes
+ * with -fPIC :
+ * error: PIC register 'ebx' clobbered in 'asm'
+ */
+static inline void sync_core(void)
+{
+       mb();
+}
+#else
+static inline void sync_core(void)
+{
+       asm volatile("cpuid" : : : "memory", "eax", "ebx", "ecx", "edx");
+}
+#endif
+
 #define rdtscll(val)                                                     \
        do {                                                              \
             unsigned int __a, __d;                                       \