Commit 2505a51a authored by Marco Elver's avatar Marco Elver Committed by Paul E. McKenney
Browse files

locking/barriers, kcsan: Support generic instrumentation 



Thus far only smp_*() barriers had been defined by asm-generic/barrier.h
based on __smp_*() barriers, because the !SMP case is usually generic.

With the introduction of instrumentation, it also makes sense to have
asm-generic/barrier.h assist in the definition of instrumented versions
of mb(), rmb(), wmb(), dma_rmb(), and dma_wmb().

Because there is no requirement to distinguish the !SMP case, the
definition can be simpler: we can avoid also providing fallbacks for the
__ prefixed cases, and only check if `defined(__<barrier>)`, to finally
define the KCSAN-instrumented versions.

This also allows for the compiler to complain if an architecture
accidentally defines both the normal and __ prefixed variant.

Signed-off-by: default avatarMarco Elver <elver@google.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent f948666d

include/asm-generic/barrier.h

+25 −0
Original line number Diff line number Diff line
@@ -21,6 +21,31 @@ 
#define nop()	asm volatile ("nop")

#endif



/*

 * Architectures that want generic instrumentation can define __ prefixed

 * variants of all barriers.

 */



#ifdef __mb

#define mb()	do { kcsan_mb(); __mb(); } while (0)

#endif



#ifdef __rmb

#define rmb()	do { kcsan_rmb(); __rmb(); } while (0)

#endif



#ifdef __wmb

#define wmb()	do { kcsan_wmb(); __wmb(); } while (0)

#endif



#ifdef __dma_rmb

#define dma_rmb()	do { kcsan_rmb(); __dma_rmb(); } while (0)

#endif



#ifdef __dma_wmb

#define dma_wmb()	do { kcsan_wmb(); __dma_wmb(); } while (0)

#endif



/*

 * Force strict CPU ordering. And yes, this is required on UP too when we're

 * talking to devices.