1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_UM_BARRIER_H_ 3 #define _ASM_UM_BARRIER_H_ 4 5 #include <asm/cpufeatures.h> 6 #include <asm/alternative.h> 7 8 /* 9 * Force strict CPU ordering. 10 * And yes, this is required on UP too when we're talking 11 * to devices. 12 */ 13 #ifdef CONFIG_X86_32 14 15 #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2) 16 #define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2) 17 #define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM) 18 19 #else /* CONFIG_X86_32 */ 20 21 #define mb() asm volatile("mfence" : : : "memory") 22 #define rmb() asm volatile("lfence" : : : "memory") 23 #define wmb() asm volatile("sfence" : : : "memory") 24 25 #endif /* CONFIG_X86_32 */ 26 27 #include <asm-generic/barrier.h> 28 29 #endif 30