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 MAX_SCHEDULE_TIMEOUT LONG_MAX 70 71 /* 72 * schedule_timeout: puts the current thread to sleep until timeout 73 * if its state allows it to. 74 */ 75 static inline long 76 schedule_timeout(signed long timeout) 77 { 78 unsigned long time_before, time_after; 79 long slept, ret = 0; 80 int timo; 81 82 if (timeout < 0) { 83 kprintf("schedule_timeout(): timeout cannot be negative\n"); 84 goto done; 85 } 86 87 /* 88 * Indefinite wait if timeout is MAX_SCHEDULE_TIMEOUT, but we are 89 * also translating to an integer. The first conditional will 90 * cover both but to code defensively test both. 91 */ 92 if (timeout >= INT_MAX || timeout == MAX_SCHEDULE_TIMEOUT) 93 timo = 0; 94 else 95 timo = timeout; 96 97 switch (current->state) { 98 case TASK_INTERRUPTIBLE: 99 time_before = ticks; 100 tsleep(current, PCATCH, "lstim", timo); 101 time_after = ticks; 102 slept = time_after - time_before; 103 ret = timeout - slept; 104 if (ret < 0) 105 ret = 0; 106 break; 107 case TASK_UNINTERRUPTIBLE: 108 tsleep(current, 0, "lstim", timo); 109 break; 110 default: 111 /* We are supposed to return immediately here */ 112 tsleep(current, 0, "lstim", 1); 113 break; 114 } 115 116 done: 117 if (timeout == MAX_SCHEDULE_TIMEOUT) 118 ret = MAX_SCHEDULE_TIMEOUT; 119 120 current->state = TASK_RUNNING; 121 return ret; 122 } 123 124 #define TASK_COMM_LEN MAXCOMLEN 125 126 /* 127 * local_clock: fast time source, monotonic on the same cpu 128 */ 129 static inline uint64_t 130 local_clock(void) 131 { 132 struct timespec ts; 133 134 getnanouptime(&ts); 135 return (ts.tv_sec * NSEC_PER_SEC) + ts.tv_nsec; 136 } 137 138 static inline void 139 yield(void) 140 { 141 lwkt_yield(); 142 } 143 144 #define __set_current_state(state_value) current->state = (state_value); 145 146 #define set_current_state(state_value) \ 147 do { \ 148 __set_current_state(state_value); \ 149 mb(); \ 150 } while (0) 151 152 static inline int 153 wake_up_process(struct task_struct *tsk) 154 { 155 /* Among other things, this function is supposed to act as 156 * a barrier */ 157 smp_wmb(); 158 wakeup(tsk); 159 160 return 0; 161 } 162 163 static inline int 164 signal_pending(struct task_struct *p) 165 { 166 struct thread *t = container_of(p, struct thread, td_linux_task); 167 168 return CURSIG(t->td_lwp); 169 } 170 171 static inline int 172 signal_pending_state(long state, struct task_struct *p) 173 { 174 struct thread *t = container_of(p, struct thread, td_linux_task); 175 sigset_t pending_set; 176 177 if (!(state & TASK_INTERRUPTIBLE)) 178 return 0; 179 180 pending_set = lwp_sigpend(t->td_lwp); 181 182 return SIGISMEMBER(pending_set, SIGKILL); 183 } 184 185 /* Explicit rescheduling in order to reduce latency */ 186 static inline int 187 cond_resched(void) 188 { 189 lwkt_yield(); 190 return 0; 191 } 192 193 static inline int 194 send_sig(int sig, struct proc *p, int priv) 195 { 196 ksignal(p, sig); 197 return 0; 198 } 199 200 static inline void 201 set_need_resched(void) 202 { 203 /* do nothing for now */ 204 /* used on ttm_bo_reserve failures */ 205 } 206 207 #endif /* _LINUX_SCHED_H_ */ 208