arch/um/include/sysdep-x86_64/barrier.h - LeafOS-Devices/android_kernel_realme_mt6785 - Gitiles

 #ifndef __SYSDEP_X86_64_BARRIER_H
 #define __SYSDEP_X86_64_BARRIER_H

 /* Copied from include/asm-x86_64 for use by userspace. */
 #define mb() 	asm volatile("mfence":::"memory")

 #endif
	#ifndef __SYSDEP_X86_64_BARRIER_H
	#define __SYSDEP_X86_64_BARRIER_H

	/* Copied from include/asm-x86_64 for use by userspace. */
	#define mb() asm volatile("mfence":::"memory")

	#endif