diff options
Diffstat (limited to 'include/qemu/atomic.h')
| -rw-r--r-- | include/qemu/atomic.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h index 0cce246ea9..c4f6950fcb 100644 --- a/include/qemu/atomic.h +++ b/include/qemu/atomic.h @@ -82,7 +82,7 @@ */ #if defined(__SANITIZE_THREAD__) #define smp_read_barrier_depends() ({ barrier(); __atomic_thread_fence(__ATOMIC_CONSUME); }) -#elsif defined(__alpha__) +#elif defined(__alpha__) #define smp_read_barrier_depends() asm volatile("mb":::"memory") #else #define smp_read_barrier_depends() barrier() @@ -92,6 +92,12 @@ /* Weak atomic operations prevent the compiler moving other * loads/stores past the atomic operation load/store. However there is * no explicit memory barrier for the processor. + * + * The C11 memory model says that variables that are accessed from + * different threads should at least be done with __ATOMIC_RELAXED + * primitives or the result is undefined. Generally this has little to + * no effect on the generated code but not using the atomic primitives + * will get flagged by sanitizers as a violation. */ #define atomic_read(ptr) \ ({ \ |