x86/barriers, kcsan: Use generic instrumentation for non-smp barriers

Prefix all barriers with __, now that asm-generic/barriers.h supports
defining the final instrumented version of these barriers. The change is
limited to barriers used by x86-64.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

arch/x86/include/asm/barrier.h

@@ -19,9 +19,9 @@
 #define wmb() asm volatile(ALTERNATIVE("lock; addl $0,-4(%%esp)", "sfence", \
 				       X86_FEATURE_XMM2) ::: "memory", "cc")
 #else
-#define mb() 	asm volatile("mfence":::"memory")
-#define rmb()	asm volatile("lfence":::"memory")
-#define wmb()	asm volatile("sfence" ::: "memory")
+#define __mb()	asm volatile("mfence":::"memory")
+#define __rmb()	asm volatile("lfence":::"memory")
+#define __wmb()	asm volatile("sfence" ::: "memory")
 #endif
 
 /**
@@ -51,8 +51,8 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
 /* Prevent speculative execution past this barrier. */
 #define barrier_nospec() alternative("", "lfence", X86_FEATURE_LFENCE_RDTSC)
 
-#define dma_rmb()	barrier()
-#define dma_wmb()	barrier()
+#define __dma_rmb()	barrier()
+#define __dma_wmb()	barrier()
 
 #define __smp_mb()	asm volatile("lock; addl $0,-4(%%" _ASM_SP ")" ::: "memory", "cc")