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