1 /* 2 * Copyright (c) 2015-2019 François Tigeot <ftigeot@wolfpond.org> 3 * Copyright (c) 2019 Matthew Dillon <dillon@backplane.com> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice unmodified, this list of conditions, and the following 11 * disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #ifndef _LINUX_SCHED_H_ 29 #define _LINUX_SCHED_H_ 30 31 #include <linux/capability.h> 32 #include <linux/threads.h> 33 #include <linux/kernel.h> 34 #include <linux/types.h> 35 #include <linux/jiffies.h> 36 #include <linux/rbtree.h> 37 #include <linux/cpumask.h> 38 #include <linux/errno.h> 39 #include <linux/mm_types.h> 40 #include <linux/preempt.h> 41 42 #include <asm/page.h> 43 44 #include <linux/compiler.h> 45 #include <linux/completion.h> 46 #include <linux/pid.h> 47 #include <linux/rcupdate.h> 48 #include <linux/rculist.h> 49 50 #include <linux/time.h> 51 #include <linux/timer.h> 52 #include <linux/hrtimer.h> 53 #include <linux/gfp.h> 54 55 #include <asm/processor.h> 56 57 #include <linux/spinlock.h> 58 59 #include <sys/param.h> 60 #include <sys/systm.h> 61 #include <sys/proc.h> 62 #include <sys/sched.h> 63 #include <sys/signal2.h> 64 65 #define TASK_RUNNING 0 66 #define TASK_INTERRUPTIBLE 1 67 #define TASK_UNINTERRUPTIBLE 2 68 69 #define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) 70 71 #define MAX_SCHEDULE_TIMEOUT LONG_MAX 72 73 /* 74 * schedule_timeout: puts the current thread to sleep until timeout 75 * if its state allows it to. 76 */ 77 static inline long 78 schedule_timeout(signed long timeout) 79 { 80 unsigned long time_before, time_after; 81 long slept, ret = 0; 82 int timo; 83 84 if (timeout < 0) { 85 kprintf("schedule_timeout(): timeout cannot be negative\n"); 86 goto done; 87 } 88 89 /* 90 * Indefinite wait if timeout is MAX_SCHEDULE_TIMEOUT, but we are 91 * also translating to an integer. The first conditional will 92 * cover both but to code defensively test both. 93 */ 94 if (timeout >= INT_MAX || timeout == MAX_SCHEDULE_TIMEOUT) 95 timo = 0; 96 else 97 timo = timeout; 98 99 switch (current->state) { 100 case TASK_INTERRUPTIBLE: 101 time_before = ticks; 102 tsleep(current, PCATCH, "lstim", timo); 103 time_after = ticks; 104 slept = time_after - time_before; 105 ret = timeout - slept; 106 if (ret < 0) 107 ret = 0; 108 break; 109 case TASK_UNINTERRUPTIBLE: 110 tsleep(current, 0, "lstim", timo); 111 break; 112 default: 113 /* We are supposed to return immediately here */ 114 tsleep(current, 0, "lstim", 1); 115 break; 116 } 117 118 done: 119 if (timeout == MAX_SCHEDULE_TIMEOUT) 120 ret = MAX_SCHEDULE_TIMEOUT; 121 122 current->state = TASK_RUNNING; 123 return ret; 124 } 125 126 static inline long 127 io_schedule_timeout(signed long timeout) 128 { 129 return schedule_timeout(timeout); 130 } 131 132 #define TASK_COMM_LEN MAXCOMLEN 133 134 /* 135 * local_clock: fast time source, monotonic on the same cpu 136 */ 137 static inline uint64_t 138 local_clock(void) 139 { 140 struct timespec ts; 141 142 getnanouptime(&ts); 143 return (ts.tv_sec * NSEC_PER_SEC) + ts.tv_nsec; 144 } 145 146 static inline void 147 yield(void) 148 { 149 lwkt_yield(); 150 } 151 152 #define __set_current_state(state_value) current->state = (state_value); 153 154 #define set_current_state(state_value) \ 155 do { \ 156 __set_current_state(state_value); \ 157 mb(); \ 158 } while (0) 159 160 static inline int 161 wake_up_process(struct task_struct *tsk) 162 { 163 /* Among other things, this function is supposed to act as 164 * a barrier */ 165 smp_wmb(); 166 wakeup(tsk); 167 168 return 1; /* Always indicate the process was woken up */ 169 } 170 171 static inline int 172 signal_pending(struct task_struct *p) 173 { 174 struct thread *t = container_of(p, struct thread, td_linux_task); 175 176 return CURSIG(t->td_lwp); 177 } 178 179 static inline int 180 signal_pending_state(long state, struct task_struct *p) 181 { 182 struct thread *t = container_of(p, struct thread, td_linux_task); 183 sigset_t pending_set; 184 185 if (!(state & TASK_INTERRUPTIBLE)) 186 return 0; 187 188 pending_set = lwp_sigpend(t->td_lwp); 189 190 return SIGISMEMBER(pending_set, SIGKILL); 191 } 192 193 /* Explicit rescheduling in order to reduce latency */ 194 static inline int 195 cond_resched(void) 196 { 197 lwkt_yield(); 198 return 0; 199 } 200 201 static inline int 202 send_sig(int sig, struct proc *p, int priv) 203 { 204 ksignal(p, sig); 205 return 0; 206 } 207 208 static inline void 209 set_need_resched(void) 210 { 211 /* do nothing for now */ 212 /* used on ttm_bo_reserve failures */ 213 } 214 215 #endif /* _LINUX_SCHED_H_ */ 216