Richard Weinberger | a3a85a7 | 2012-03-29 18:47:46 +0200 | [diff] [blame] | 1 | #ifndef _ASM_UM_BARRIER_H_ |
| 2 | #define _ASM_UM_BARRIER_H_ |
| 3 | |
| 4 | #include <asm/asm.h> |
| 5 | #include <asm/segment.h> |
| 6 | #include <asm/cpufeature.h> |
| 7 | #include <asm/cmpxchg.h> |
| 8 | #include <asm/nops.h> |
| 9 | |
| 10 | #include <linux/kernel.h> |
| 11 | #include <linux/irqflags.h> |
| 12 | |
| 13 | /* |
| 14 | * Force strict CPU ordering. |
| 15 | * And yes, this is required on UP too when we're talking |
| 16 | * to devices. |
| 17 | */ |
| 18 | #ifdef CONFIG_X86_32 |
| 19 | |
| 20 | #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2) |
| 21 | #define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2) |
| 22 | #define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM) |
| 23 | |
| 24 | #else /* CONFIG_X86_32 */ |
| 25 | |
| 26 | #define mb() asm volatile("mfence" : : : "memory") |
| 27 | #define rmb() asm volatile("lfence" : : : "memory") |
| 28 | #define wmb() asm volatile("sfence" : : : "memory") |
| 29 | |
| 30 | #endif /* CONFIG_X86_32 */ |
| 31 | |
| 32 | #define read_barrier_depends() do { } while (0) |
| 33 | |
| 34 | #ifdef CONFIG_SMP |
| 35 | |
| 36 | #define smp_mb() mb() |
| 37 | #ifdef CONFIG_X86_PPRO_FENCE |
| 38 | #define smp_rmb() rmb() |
| 39 | #else /* CONFIG_X86_PPRO_FENCE */ |
| 40 | #define smp_rmb() barrier() |
| 41 | #endif /* CONFIG_X86_PPRO_FENCE */ |
| 42 | |
| 43 | #ifdef CONFIG_X86_OOSTORE |
| 44 | #define smp_wmb() wmb() |
| 45 | #else /* CONFIG_X86_OOSTORE */ |
| 46 | #define smp_wmb() barrier() |
| 47 | #endif /* CONFIG_X86_OOSTORE */ |
| 48 | |
| 49 | #define smp_read_barrier_depends() read_barrier_depends() |
| 50 | #define set_mb(var, value) do { (void)xchg(&var, value); } while (0) |
| 51 | |
| 52 | #else /* CONFIG_SMP */ |
| 53 | |
| 54 | #define smp_mb() barrier() |
| 55 | #define smp_rmb() barrier() |
| 56 | #define smp_wmb() barrier() |
| 57 | #define smp_read_barrier_depends() do { } while (0) |
| 58 | #define set_mb(var, value) do { var = value; barrier(); } while (0) |
| 59 | |
| 60 | #endif /* CONFIG_SMP */ |
| 61 | |
| 62 | /* |
| 63 | * Stop RDTSC speculation. This is needed when you need to use RDTSC |
| 64 | * (or get_cycles or vread that possibly accesses the TSC) in a defined |
| 65 | * code region. |
| 66 | * |
| 67 | * (Could use an alternative three way for this if there was one.) |
| 68 | */ |
| 69 | static inline void rdtsc_barrier(void) |
| 70 | { |
| 71 | alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC); |
| 72 | alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC); |
| 73 | } |
| 74 | |
| 75 | #endif |