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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 | /* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2016 Red Hat, Inc. * Author: Michael S. Tsirkin <mst@redhat.com> * * Common macros and functions for ring benchmarking. */ #ifndef MAIN_H #define MAIN_H #include <stdbool.h> extern int param; extern bool do_exit; #if defined(__x86_64__) || defined(__i386__) #include "x86intrin.h" static inline void wait_cycles(unsigned long long cycles) { unsigned long long t; t = __rdtsc(); while (__rdtsc() - t < cycles) {} } #define VMEXIT_CYCLES 500 #define VMENTRY_CYCLES 500 #elif defined(__s390x__) static inline void wait_cycles(unsigned long long cycles) { asm volatile("0: brctg %0,0b" : : "d" (cycles)); } /* tweak me */ #define VMEXIT_CYCLES 200 #define VMENTRY_CYCLES 200 #else static inline void wait_cycles(unsigned long long cycles) { _Exit(5); } #define VMEXIT_CYCLES 0 #define VMENTRY_CYCLES 0 #endif static inline void vmexit(void) { if (!do_exit) return; wait_cycles(VMEXIT_CYCLES); } static inline void vmentry(void) { if (!do_exit) return; wait_cycles(VMENTRY_CYCLES); } /* implemented by ring */ void alloc_ring(void); /* guest side */ int add_inbuf(unsigned, void *, void *); void *get_buf(unsigned *, void **); void disable_call(); bool used_empty(); bool enable_call(); void kick_available(); /* host side */ void disable_kick(); bool avail_empty(); bool enable_kick(); bool use_buf(unsigned *, void **); void call_used(); /* implemented by main */ extern bool do_sleep; void kick(void); void wait_for_kick(void); void call(void); void wait_for_call(void); extern unsigned ring_size; /* Compiler barrier - similar to what Linux uses */ #define barrier() asm volatile("" ::: "memory") /* Is there a portable way to do this? */ #if defined(__x86_64__) || defined(__i386__) #define cpu_relax() asm ("rep; nop" ::: "memory") #elif defined(__s390x__) #define cpu_relax() barrier() #else #define cpu_relax() assert(0) #endif extern bool do_relax; static inline void busy_wait(void) { if (do_relax) cpu_relax(); else /* prevent compiler from removing busy loops */ barrier(); } #if defined(__x86_64__) || defined(__i386__) #define smp_mb() asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc") #else /* * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized * with other __ATOMIC_SEQ_CST calls. */ #define smp_mb() __sync_synchronize() #endif /* * This abuses the atomic builtins for thread fences, and * adds a compiler barrier. */ #define smp_release() do { \ barrier(); \ __atomic_thread_fence(__ATOMIC_RELEASE); \ } while (0) #define smp_acquire() do { \ __atomic_thread_fence(__ATOMIC_ACQUIRE); \ barrier(); \ } while (0) #if defined(__i386__) || defined(__x86_64__) || defined(__s390x__) #define smp_wmb() barrier() #else #define smp_wmb() smp_release() #endif static __always_inline void __read_once_size(const volatile void *p, void *res, int size) { switch (size) { case 1: *(unsigned char *)res = *(volatile unsigned char *)p; break; case 2: *(unsigned short *)res = *(volatile unsigned short *)p; break; case 4: *(unsigned int *)res = *(volatile unsigned int *)p; break; case 8: *(unsigned long long *)res = *(volatile unsigned long long *)p; break; default: barrier(); __builtin_memcpy((void *)res, (const void *)p, size); barrier(); } } static __always_inline void __write_once_size(volatile void *p, void *res, int size) { switch (size) { case 1: *(volatile unsigned char *)p = *(unsigned char *)res; break; case 2: *(volatile unsigned short *)p = *(unsigned short *)res; break; case 4: *(volatile unsigned int *)p = *(unsigned int *)res; break; case 8: *(volatile unsigned long long *)p = *(unsigned long long *)res; break; default: barrier(); __builtin_memcpy((void *)p, (const void *)res, size); barrier(); } } #ifdef __alpha__ #define READ_ONCE(x) \ ({ \ union { typeof(x) __val; char __c[1]; } __u; \ __read_once_size(&(x), __u.__c, sizeof(x)); \ smp_mb(); /* Enforce dependency ordering from x */ \ __u.__val; \ }) #else #define READ_ONCE(x) \ ({ \ union { typeof(x) __val; char __c[1]; } __u; \ __read_once_size(&(x), __u.__c, sizeof(x)); \ __u.__val; \ }) #endif #define WRITE_ONCE(x, val) \ ({ \ union { typeof(x) __val; char __c[1]; } __u = \ { .__val = (typeof(x)) (val) }; \ __write_once_size(&(x), __u.__c, sizeof(x)); \ __u.__val; \ }) #endif |