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 struct task_struct { 77 struct thread *dfly_td; 78 volatile long state; 79 struct mm_struct *mm; /* mirror copy in p->p_linux_mm */ 80 int prio; 81 }; 82 83 /* 84 * schedule_timeout: puts the current thread to sleep until timeout 85 * if its state allows it to. 86 */ 87 static inline long 88 schedule_timeout(signed long timeout) 89 { 90 unsigned long time_before, time_after; 91 long slept, ret = 0; 92 int timo; 93 94 if (timeout < 0) { 95 kprintf("schedule_timeout(): timeout cannot be negative\n"); 96 goto done; 97 } 98 99 /* 100 * Indefinite wait if timeout is MAX_SCHEDULE_TIMEOUT, but we are 101 * also translating to an integer. The first conditional will 102 * cover both but to code defensively test both. 103 */ 104 if (timeout >= INT_MAX || timeout == MAX_SCHEDULE_TIMEOUT) 105 timo = 0; 106 else 107 timo = timeout; 108 109 switch (current->state) { 110 case TASK_INTERRUPTIBLE: 111 time_before = ticks; 112 tsleep(current, PCATCH, "lstim", timo); 113 time_after = ticks; 114 slept = time_after - time_before; 115 ret = timeout - slept; 116 if (ret < 0) 117 ret = 0; 118 break; 119 case TASK_UNINTERRUPTIBLE: 120 tsleep(current, 0, "lstim", timo); 121 break; 122 default: 123 /* We are supposed to return immediately here */ 124 tsleep(current, 0, "lstim", 1); 125 break; 126 } 127 128 done: 129 if (timeout == MAX_SCHEDULE_TIMEOUT) 130 ret = MAX_SCHEDULE_TIMEOUT; 131 132 current->state = TASK_RUNNING; 133 return ret; 134 } 135 136 static inline long 137 io_schedule_timeout(signed long timeout) 138 { 139 return schedule_timeout(timeout); 140 } 141 142 #define TASK_COMM_LEN MAXCOMLEN 143 144 /* 145 * local_clock: fast time source, monotonic on the same cpu 146 */ 147 static inline uint64_t 148 local_clock(void) 149 { 150 struct timespec ts; 151 152 getnanouptime(&ts); 153 return (ts.tv_sec * NSEC_PER_SEC) + ts.tv_nsec; 154 } 155 156 static inline void 157 yield(void) 158 { 159 lwkt_yield(); 160 } 161 162 #define __set_current_state(state_value) current->state = (state_value); 163 164 #define set_current_state(state_value) \ 165 do { \ 166 __set_current_state(state_value); \ 167 mb(); \ 168 } while (0) 169 170 static inline int 171 wake_up_process(struct task_struct *tsk) 172 { 173 /* Among other things, this function is supposed to act as 174 * a barrier */ 175 smp_wmb(); 176 wakeup(tsk); 177 178 return 1; /* Always indicate the process was woken up */ 179 } 180 181 static inline int 182 signal_pending(struct task_struct *p) 183 { 184 struct thread *t = p->dfly_td; 185 186 /* Some kernel threads do not have lwp, t->td_lwp can be NULL */ 187 if (t->td_lwp == NULL) 188 return 0; 189 190 return CURSIG(t->td_lwp); 191 } 192 193 static inline int 194 fatal_signal_pending(struct task_struct *p) 195 { 196 struct thread *t = p->dfly_td; 197 sigset_t pending_set; 198 199 /* Some kernel threads do not have lwp, t->td_lwp can be NULL */ 200 if (t->td_lwp == NULL) 201 return 0; 202 203 pending_set = lwp_sigpend(t->td_lwp); 204 return SIGISMEMBER(pending_set, SIGKILL); 205 } 206 207 static inline int 208 signal_pending_state(long state, struct task_struct *p) 209 { 210 if (state & TASK_INTERRUPTIBLE) 211 return (signal_pending(p)); 212 else 213 return (fatal_signal_pending(p)); 214 } 215 216 /* Explicit rescheduling in order to reduce latency */ 217 static inline int 218 cond_resched(void) 219 { 220 lwkt_yield(); 221 return 0; 222 } 223 224 static inline int 225 send_sig(int sig, struct proc *p, int priv) 226 { 227 ksignal(p, sig); 228 return 0; 229 } 230 231 static inline void 232 set_need_resched(void) 233 { 234 /* do nothing for now */ 235 /* used on ttm_bo_reserve failures */ 236 } 237 238 #endif /* _LINUX_SCHED_H_ */ 239