Commit b7c47fd7 authored by Will Deacon's avatar Will Deacon
Browse files

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()
parents 570365d3 4d09caec

Documentation/memory-barriers.txt

+6 −5
Original line number Diff line number Diff line
@@ -1894,6 +1894,7 @@ There are some more advanced barrier functions: 


 (*) 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
@@ -1925,11 +1926,11 @@ There are some more advanced barrier functions: 
     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

+6 −6
Original line number Diff line number Diff line
@@ -50,13 +50,13 @@ 
#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

+8 −0
Original line number Diff line number Diff line
@@ -38,6 +38,10 @@ 
#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
@@ -65,6 +69,10 @@ 
#define wmb()	mb()

#endif



#ifndef dma_mb

#define dma_mb()	mb()

#endif



#ifndef dma_rmb

#define dma_rmb()	rmb()

#endif