Merge branch 'for-next/kcsan' into for-next/core

* for-next/kcsan:
arm64: kcsan: Support detecting more missing memory barriers
asm-generic: Add memory barrier dma_mb()

Documentation/memory-barriers.txt

···
 
  (*) dma_wmb();
  (*) dma_rmb();
+ (*) dma_mb();
 
      These are for use with consistent memory to guarantee the ordering
      of writes or reads of shared memory accessible to both the CPU and a
···
      The dma_rmb() allows us guarantee the device has released ownership
      before we read the data from the descriptor, and the dma_wmb() allows
      us to guarantee the data is written to the descriptor before the device
-     can see it now has ownership.  Note that, when using writel(), a prior
-     wmb() is not needed to guarantee that the cache coherent memory writes
-     have completed before writing to the MMIO region.  The cheaper
-     writel_relaxed() does not provide this guarantee and must not be used
-     here.
+     can see it now has ownership.  The dma_mb() implies both a dma_rmb() and
+     a dma_wmb().  Note that, when using writel(), a prior wmb() is not needed
+     to guarantee that the cache coherent memory writes have completed before
+     writing to the MMIO region.  The cheaper writel_relaxed() does not provide
+     this guarantee and must not be used here.
 
      See the subsection "Kernel I/O barrier effects" for more information on
      relaxed I/O accessors and the Documentation/core-api/dma-api.rst file for

arch/arm64/include/asm/barrier.h

···
 #define pmr_sync()	do {} while (0)
 #endif
 
-#define mb()		dsb(sy)
-#define rmb()		dsb(ld)
-#define wmb()		dsb(st)
+#define __mb()		dsb(sy)
+#define __rmb()		dsb(ld)
+#define __wmb()		dsb(st)
 
-#define dma_mb()	dmb(osh)
-#define dma_rmb()	dmb(oshld)
-#define dma_wmb()	dmb(oshst)
+#define __dma_mb()	dmb(osh)
+#define __dma_rmb()	dmb(oshld)
+#define __dma_wmb()	dmb(oshst)
 
 #define io_stop_wc()	dgh()
 

include/asm-generic/barrier.h

···
 #define wmb()	do { kcsan_wmb(); __wmb(); } while (0)
 #endif
 
+#ifdef __dma_mb
+#define dma_mb()	do { kcsan_mb(); __dma_mb(); } while (0)
+#endif
+
 #ifdef __dma_rmb
 #define dma_rmb()	do { kcsan_rmb(); __dma_rmb(); } while (0)
 #endif
···
 
 #ifndef wmb
 #define wmb()	mb()
+#endif
+
+#ifndef dma_mb
+#define dma_mb()	mb()
 #endif
 
 #ifndef dma_rmb