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/smp.h> 45 #include <linux/compiler.h> 46 #include <linux/completion.h> 47 #include <linux/pid.h> 48 #include <linux/rcupdate.h> 49 #include <linux/rculist.h> 50 51 #include <linux/time.h> 52 #include <linux/timer.h> 53 #include <linux/hrtimer.h> 54 #include <linux/gfp.h> 55 56 #include <asm/processor.h> 57 58 #include <linux/spinlock.h> 59 60 #include <sys/param.h> 61 #include <sys/systm.h> 62 #include <sys/proc.h> 63 #include <sys/sched.h> 64 #include <sys/signal2.h> 65 66 struct seq_file; 67 68 #define TASK_RUNNING 0 69 #define TASK_INTERRUPTIBLE 1 70 #define TASK_UNINTERRUPTIBLE 2 71 72 #define TASK_NORMAL (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE) 73 74 #define MAX_SCHEDULE_TIMEOUT LONG_MAX 75 76 /* 77 * schedule_timeout: puts the current thread to sleep until timeout 78 * if its state allows it to. 79 */ 80 static inline long 81 schedule_timeout(signed long timeout) 82 { 83 unsigned long time_before, time_after; 84 long slept, ret = 0; 85 int timo; 86 87 if (timeout < 0) { 88 kprintf("schedule_timeout(): timeout cannot be negative\n"); 89 goto done; 90 } 91 92 /* 93 * Indefinite wait if timeout is MAX_SCHEDULE_TIMEOUT, but we are 94 * also translating to an integer. The first conditional will 95 * cover both but to code defensively test both. 96 */ 97 if (timeout >= INT_MAX || timeout == MAX_SCHEDULE_TIMEOUT) 98 timo = 0; 99 else 100 timo = timeout; 101 102 switch (current->state) { 103 case TASK_INTERRUPTIBLE: 104 time_before = ticks; 105 tsleep(current, PCATCH, "lstim", timo); 106 time_after = ticks; 107 slept = time_after - time_before; 108 ret = timeout - slept; 109 if (ret < 0) 110 ret = 0; 111 break; 112 case TASK_UNINTERRUPTIBLE: 113 tsleep(current, 0, "lstim", timo); 114 break; 115 default: 116 /* We are supposed to return immediately here */ 117 tsleep(current, 0, "lstim", 1); 118 break; 119 } 120 121 done: 122 if (timeout == MAX_SCHEDULE_TIMEOUT) 123 ret = MAX_SCHEDULE_TIMEOUT; 124 125 current->state = TASK_RUNNING; 126 return ret; 127 } 128 129 static inline long 130 io_schedule_timeout(signed long timeout) 131 { 132 return schedule_timeout(timeout); 133 } 134 135 #define TASK_COMM_LEN MAXCOMLEN 136 137 /* 138 * local_clock: fast time source, monotonic on the same cpu 139 */ 140 static inline uint64_t 141 local_clock(void) 142 { 143 struct timespec ts; 144 145 getnanouptime(&ts); 146 return (ts.tv_sec * NSEC_PER_SEC) + ts.tv_nsec; 147 } 148 149 static inline void 150 yield(void) 151 { 152 lwkt_yield(); 153 } 154 155 #define __set_current_state(state_value) current->state = (state_value); 156 157 #define set_current_state(state_value) \ 158 do { \ 159 __set_current_state(state_value); \ 160 mb(); \ 161 } while (0) 162 163 static inline int 164 wake_up_process(struct task_struct *tsk) 165 { 166 /* Among other things, this function is supposed to act as 167 * a barrier */ 168 smp_wmb(); 169 wakeup(tsk); 170 171 return 1; /* Always indicate the process was woken up */ 172 } 173 174 static inline int 175 signal_pending(struct task_struct *p) 176 { 177 struct thread *t = p->dfly_td; 178 179 /* Some kernel threads do not have lwp, t->td_lwp can be NULL */ 180 if (t->td_lwp == NULL) 181 return 0; 182 183 return CURSIG(t->td_lwp); 184 } 185 186 static inline int 187 fatal_signal_pending(struct task_struct *p) 188 { 189 struct thread *t = p->dfly_td; 190 sigset_t pending_set; 191 192 /* Some kernel threads do not have lwp, t->td_lwp can be NULL */ 193 if (t->td_lwp == NULL) 194 return 0; 195 196 pending_set = lwp_sigpend(t->td_lwp); 197 return SIGISMEMBER(pending_set, SIGKILL); 198 } 199 200 static inline int 201 signal_pending_state(long state, struct task_struct *p) 202 { 203 if (state & TASK_INTERRUPTIBLE) 204 return (signal_pending(p)); 205 else 206 return (fatal_signal_pending(p)); 207 } 208 209 /* Explicit rescheduling in order to reduce latency */ 210 static inline int 211 cond_resched(void) 212 { 213 lwkt_yield(); 214 return 0; 215 } 216 217 static inline int 218 send_sig(int sig, struct proc *p, int priv) 219 { 220 ksignal(p, sig); 221 return 0; 222 } 223 224 static inline void 225 set_need_resched(void) 226 { 227 /* do nothing for now */ 228 /* used on ttm_bo_reserve failures */ 229 } 230 231 #endif /* _LINUX_SCHED_H_ */ 232