1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_UM_BARRIER_H_ 3 #define _ASM_UM_BARRIER_H_ 4 5 #include <asm/asm.h> 6 #include <asm/segment.h> 7 #include <asm/cpufeatures.h> 8 #include <asm/cmpxchg.h> 9 #include <asm/nops.h> 10 11 #include <linux/kernel.h> 12 #include <linux/irqflags.h> 13 14 /* 15 * Force strict CPU ordering. 16 * And yes, this is required on UP too when we're talking 17 * to devices. 18 */ 19 #ifdef CONFIG_X86_32 20 21 #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2) 22 #define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2) 23 #define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM) 24 25 #else /* CONFIG_X86_32 */ 26 27 #define mb() asm volatile("mfence" : : : "memory") 28 #define rmb() asm volatile("lfence" : : : "memory") 29 #define wmb() asm volatile("sfence" : : : "memory") 30 31 #endif /* CONFIG_X86_32 */ 32 33 #define dma_rmb() barrier() 34 #define dma_wmb() barrier() 35 36 #include <asm-generic/barrier.h> 37 38 #endif 39