1 /* SPDX-License-Identifier: BSD-3-Clause 2 * Copyright (c) 2020 Dmitry Kozlyuk 3 */ 4 5 #include <stdatomic.h> 6 #include <stdbool.h> 7 #include <sys/queue.h> 8 9 #include <rte_alarm.h> 10 #include <rte_spinlock.h> 11 12 #include "eal_private.h" 13 #include <eal_trace_internal.h> 14 #include "eal_windows.h" 15 16 enum alarm_state { 17 ALARM_ARMED, 18 ALARM_TRIGGERED, 19 ALARM_CANCELLED 20 }; 21 22 struct alarm_entry { 23 LIST_ENTRY(alarm_entry) next; 24 rte_eal_alarm_callback cb_fn; 25 void *cb_arg; 26 HANDLE timer; 27 atomic_uint state; 28 }; 29 30 static LIST_HEAD(alarm_list, alarm_entry) alarm_list = LIST_HEAD_INITIALIZER(); 31 32 static rte_spinlock_t alarm_lock = RTE_SPINLOCK_INITIALIZER; 33 34 static int intr_thread_exec_sync(void (*func)(void *arg), void *arg); 35 36 static void 37 alarm_remove_unsafe(struct alarm_entry *ap) 38 { 39 LIST_REMOVE(ap, next); 40 CloseHandle(ap->timer); 41 free(ap); 42 } 43 44 static void 45 alarm_callback(void *arg, DWORD low __rte_unused, DWORD high __rte_unused) 46 { 47 struct alarm_entry *ap = arg; 48 unsigned int state = ALARM_ARMED; 49 50 if (!atomic_compare_exchange_strong( 51 &ap->state, &state, ALARM_TRIGGERED)) 52 return; 53 54 ap->cb_fn(ap->cb_arg); 55 56 rte_spinlock_lock(&alarm_lock); 57 alarm_remove_unsafe(ap); 58 rte_spinlock_unlock(&alarm_lock); 59 } 60 61 static int 62 alarm_set(struct alarm_entry *entry, LARGE_INTEGER deadline) 63 { 64 BOOL ret = SetWaitableTimer( 65 entry->timer, &deadline, 0, alarm_callback, entry, FALSE); 66 if (!ret) { 67 RTE_LOG_WIN32_ERR("SetWaitableTimer"); 68 return -1; 69 } 70 return 0; 71 } 72 73 struct alarm_task { 74 struct alarm_entry *entry; 75 LARGE_INTEGER deadline; 76 int ret; 77 }; 78 79 static void 80 alarm_task_exec(void *arg) 81 { 82 struct alarm_task *task = arg; 83 task->ret = alarm_set(task->entry, task->deadline); 84 } 85 86 int 87 rte_eal_alarm_set(uint64_t us, rte_eal_alarm_callback cb_fn, void *cb_arg) 88 { 89 struct alarm_entry *ap; 90 HANDLE timer; 91 FILETIME ft; 92 LARGE_INTEGER deadline; 93 int ret; 94 95 if (cb_fn == NULL) { 96 EAL_LOG(ERR, "NULL callback"); 97 ret = -EINVAL; 98 goto exit; 99 } 100 101 /* Calculate deadline ASAP, unit of measure = 100ns. */ 102 GetSystemTimePreciseAsFileTime(&ft); 103 deadline.LowPart = ft.dwLowDateTime; 104 deadline.HighPart = ft.dwHighDateTime; 105 deadline.QuadPart += 10 * us; 106 107 ap = calloc(1, sizeof(*ap)); 108 if (ap == NULL) { 109 EAL_LOG(ERR, "Cannot allocate alarm entry"); 110 ret = -ENOMEM; 111 goto exit; 112 } 113 114 timer = CreateWaitableTimer(NULL, FALSE, NULL); 115 if (timer == NULL) { 116 RTE_LOG_WIN32_ERR("CreateWaitableTimer()"); 117 ret = -EINVAL; 118 goto fail; 119 } 120 121 ap->timer = timer; 122 ap->cb_fn = cb_fn; 123 ap->cb_arg = cb_arg; 124 125 /* Waitable timer must be set in the same thread that will 126 * do an alertable wait for the alarm to trigger, that is, 127 * in the interrupt thread. 128 */ 129 if (rte_thread_is_intr()) { 130 /* Directly schedule callback execution. */ 131 ret = alarm_set(ap, deadline); 132 if (ret < 0) { 133 EAL_LOG(ERR, "Cannot setup alarm"); 134 goto fail; 135 } 136 } else { 137 /* Dispatch a task to set alarm into the interrupt thread. 138 * Execute it synchronously, because it can fail. 139 */ 140 struct alarm_task task = { 141 .entry = ap, 142 .deadline = deadline, 143 }; 144 145 ret = intr_thread_exec_sync(alarm_task_exec, &task); 146 if (ret < 0) { 147 EAL_LOG(ERR, "Cannot setup alarm in interrupt thread"); 148 goto fail; 149 } 150 151 ret = task.ret; 152 if (ret < 0) 153 goto fail; 154 } 155 156 rte_spinlock_lock(&alarm_lock); 157 LIST_INSERT_HEAD(&alarm_list, ap, next); 158 rte_spinlock_unlock(&alarm_lock); 159 160 goto exit; 161 162 fail: 163 if (timer != NULL) 164 CloseHandle(timer); 165 free(ap); 166 167 exit: 168 rte_eal_trace_alarm_set(us, cb_fn, cb_arg, ret); 169 return ret; 170 } 171 172 static bool 173 alarm_matches(const struct alarm_entry *ap, 174 rte_eal_alarm_callback cb_fn, void *cb_arg) 175 { 176 bool any_arg = cb_arg == (void *)(-1); 177 return (ap->cb_fn == cb_fn) && (any_arg || ap->cb_arg == cb_arg); 178 } 179 180 int 181 rte_eal_alarm_cancel(rte_eal_alarm_callback cb_fn, void *cb_arg) 182 { 183 struct alarm_entry *ap; 184 unsigned int state; 185 int removed; 186 bool executing; 187 188 removed = 0; 189 190 if (cb_fn == NULL) { 191 EAL_LOG(ERR, "NULL callback"); 192 return -EINVAL; 193 } 194 195 do { 196 executing = false; 197 198 rte_spinlock_lock(&alarm_lock); 199 200 LIST_FOREACH(ap, &alarm_list, next) { 201 if (!alarm_matches(ap, cb_fn, cb_arg)) 202 continue; 203 204 state = ALARM_ARMED; 205 if (atomic_compare_exchange_strong( 206 &ap->state, &state, ALARM_CANCELLED)) { 207 alarm_remove_unsafe(ap); 208 removed++; 209 } else if (state == ALARM_TRIGGERED) 210 executing = true; 211 } 212 213 rte_spinlock_unlock(&alarm_lock); 214 } while (executing); 215 216 rte_eal_trace_alarm_cancel(cb_fn, cb_arg, removed); 217 return removed; 218 } 219 220 struct intr_task { 221 void (*func)(void *arg); 222 void *arg; 223 rte_spinlock_t lock; /* unlocked at task completion */ 224 }; 225 226 static void 227 intr_thread_entry(void *arg) 228 __rte_no_thread_safety_analysis 229 { 230 struct intr_task *task = arg; 231 task->func(task->arg); 232 rte_spinlock_unlock(&task->lock); 233 } 234 235 static int 236 intr_thread_exec_sync(void (*func)(void *arg), void *arg) 237 __rte_no_thread_safety_analysis 238 { 239 struct intr_task task; 240 int ret; 241 242 task.func = func; 243 task.arg = arg; 244 rte_spinlock_init(&task.lock); 245 246 /* Make timers more precise by synchronizing in userspace. */ 247 rte_spinlock_lock(&task.lock); 248 ret = eal_intr_thread_schedule(intr_thread_entry, &task); 249 if (ret < 0) { 250 EAL_LOG(ERR, "Cannot schedule task to interrupt thread"); 251 return -EINVAL; 252 } 253 254 /* Wait for the task to complete. */ 255 rte_spinlock_lock(&task.lock); 256 return 0; 257 } 258